UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 10-K
ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the Fiscal Year Ended December 31, 20152018
Commission File Number Registrants, State of Incorporation, Address, and Telephone Number I.R.S. Employer Identification No.
1-11607 
DTE Energy Company
(a Michigan corporation)
One Energy Plaza
Detroit, Michigan 48226-1279
313-235-4000
 38-3217752
     
1-2198 
DTE Electric Company
(a Michigan corporation)
One Energy Plaza
Detroit, Michigan 48226-1279
313-235-4000
 38-0478650
Securities registered pursuant to Section 12(b) of the Act:
Registrant Title of Each Class Name of Exchange on which Registered
DTE Energy Company (DTE Energy) Common stock, without par value New York Stock Exchange
     
DTE Energy 20112012 Series I 6.5%C 5.25% Junior Subordinated Debentures due 20612062 New York Stock Exchange
     
DTE Energy 20122016 Series CB 5.375% Junior Subordinated Debentures due 2076New York Stock Exchange
DTE Energy2016 Series F 6.00% Junior Subordinated Debentures due 2076New York Stock Exchange
DTE Energy2017 Series E 5.25% Junior Subordinated Debentures due 20622077New York Stock Exchange
DTE Energy6.50% Corporate Units New York Stock Exchange
     
DTE Electric Company (DTE Electric) None None
Securities registered pursuant to Section 12(g) of the Act:
DTE Energy                NoneDTE Electric                 None
DTE EnergyNoneDTE ElectricNone
Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.
DTE Energy
DTE Energy                Yes o No xDTE Electric                 Yes x No o
DTE Electric
Yes x No o
Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.
DTE Energy
DTE Energy                Yes o No xDTE Electric                   Yes o No x
DTE Electric
Yes o No x
Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.
DTE Energy
DTE Energy                Yes x No oDTE Electric                 Yes x No o
DTE Electric
Yes x No o
Indicate by check mark whether the registrant has submitted electronically and posted on its corporate web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).
DTE Energy
DTE Energy                Yes x No oDTE Electric                 Yes x No o
DTE Electric
Yes x No o
Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of the registrant's knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.
DTE Energy                xDTE Electric                 x
DTE EnergyxDTE Electricx




Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company, or an emerging growth company. See the definitions of “large"large accelerated filer,” “accelerated filer”" "accelerated filer," "smaller reporting company," and “smaller reporting company”"emerging growth company" in Rule 12b-2 of the Exchange Act.
DTE Energy
Large accelerated filer x
Accelerated filer o
Non-accelerated filer o
Smaller reporting company o
Emerging growth company o
  (Do not check if a smaller reporting company)
DTE Electric
Large accelerated filer o
Accelerated filer o
Non-accelerated filer x
Smaller reporting company o
(Do not check if a smaller reporting company)
Emerging growth company o

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o



Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).
DTE Energy
DTE Energy                Yes o No xDTE Electric                Yes o No x
DTE Electric
Yes o No x
On June 30, 2015,29, 2018, the aggregate market value of DTE Energy's voting and non voting common equity held by non-affiliates was approximately $12.9 billion(based$18.5 billion (based on the New York Stock Exchange closing price on such date).
Number of shares of Common Stock outstanding at January 29, 2016:25, 2019:
Registrant Description Shares
DTE Energy Common Stock, without par value 179,476,008181,923,685
     
DTE Electric Common Stock, $10 par value, directly-owned by DTE Energy 138,632,324
DOCUMENTS INCORPORATED BY REFERENCE
Certain information in DTE Energy's definitive Proxy Statement for its 20162019 Annual Meeting of Common Shareholders to be held May 5, 2016,9, 2019, which will be filed with the Securities and Exchange Commission pursuant to Regulation 14A, not later than 120 days after the end of the registrant’s fiscal year covered by this report on Form 10-K, is incorporated herein by reference to Part III (Items 10, 11, 12, 13, and 14) of this Form 10-K.
This combined Form 10-K is filed separately by two registrants: DTE Energy and DTE Electric. Information contained herein relating to any individual registrant is filed by such registrant solely on its own behalf. DTE Electric makes no representation as to information relating exclusively to DTE Energy.
DTE Electric, a wholly-owned subsidiary of DTE Energy, meets the conditions set forth in General Instructions I(1)(a) and (b) of Form 10-K and is therefore filing this form with the reduced disclosure format specified in General Instruction I(2) of Form 10-K.
 




TABLE OF CONTENTS

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DEFINITIONS

AFUDCAllowance for Funds Used During Construction
  
AGSAppalachia Gathering System is a midstream natural gas asset located in Pennsylvania and West Virginia. DTE Energy purchased 100% of AGS in October 2016, and this asset is part of DTE Energy's Gas Storage and Pipelines segment.
AMVApplicable Market Value
ANPRAdvanced Notice of Proposed Rulemaking
AROAsset Retirement Obligation
  
ASUAccounting Standards Update issued by the FASB
  
CCRCoal Combustion Residuals
CFTCU.S. Commodity Futures Trading Commission
  
COACONU.S. CourtCertificate of Appeals for the District of ColumbiaNecessity
  
DOEU.S. Department of Energy
  
DTE ElectricDTE Electric Company (a direct wholly-owned subsidiary of DTE Energy) and subsidiary companies
  
DTE EnergyDTE Energy Company, directly or indirectly the parent of DTE Electric, DTE Gas, and numerous non-utility subsidiaries
  
DTE GasDTE Gas Company (an indirect wholly-owned subsidiary of DTE Energy) and subsidiary companies
  
EGUElectric Generating Unit
ELGEffluent Limitations Guidelines
EPAU.S. Environmental Protection Agency
  
Equity unitsDTE Energy's 2016 equity units issued in October 2016, which were used to finance the October 1, 2016 Gas Storage and Pipelines acquisition.
FASBFinancial Accounting Standards Board
  
FERCFederal Energy Regulatory Commission
  
FOVFinding of Violation
  
FTRsFinancial Transmission Rights are financial instruments that entitle the holder to receive payments related to costs incurred for congestion on the transmission grid.
  
GCRA Gas Cost Recovery mechanism authorized by the MPSC that allows DTE Gas to recover through rates its natural gas costs.
  
GHGsGreenhouse gases
  
Green BondsA financing option to fund projects that have a positive environmental impact based upon a specified set of criteria. The proceeds are required to be used for eligible green expenditures.
IRMInfrastructure Recovery Mechanism
  
IRSInternal Revenue Service
  
MBTISOMichigan Business TaxIndependent System Operator
  
MCITLIBORMichigan Corporate Income TaxLondon Inter-Bank Offered Rates
  
MCOALLCMichigan CourtDTE Energy Corporate Services, LLC, a subsidiary of AppealsDTE Energy
  
MDEQMichigan Department of Environmental Quality
  
MGPManufactured Gas Plant
  
MISOMidcontinent Independent System Operator, Inc.
  


DEFINITIONS

MPSCMichigan Public Service Commission
  
MTMMark-to-market
  
NAVNet Asset Value
  
NEILNuclear Electric Insurance Limited
  
NEXUSNEXUS Gas Transmission, LLC, a joint venture in which DTE Energy owns a 50% partnership interest.
  
Non-utilityAn entity that is not a public utility. Its conditions of service, prices of goods and services, and other operating related matters are not directly regulated by the MPSC.
  
NOVNotice of Violation
  
NOX
Nitrogen Oxides
NRCU.S. Nuclear Regulatory Commission
  
PG&EPacific Gas and Electric Corporation
PLDCity of Detroit's Public Lighting Department
  

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DEFINITIONS

Production tax creditsTax credits as authorized under Sections 45K and 45 of the Internal Revenue Code that are designed to stimulate investment in and development of alternate fuel sources. The amount of a production tax credit can vary each year as determined by the IRS.
  
PSCRA Power Supply Cost Recovery mechanism authorized by the MPSC that allows DTE Electric to recover through rates its fuel, fuel-related, and purchased power costs.
  
RDMA Revenue Decoupling Mechanism authorized by the MPSC that is designed to minimize the impact on revenues of changes in average customer usage.
  
RECRenewable Energy Credit
REFReduced Emissions Fuel
  
RegistrantsDTE Energy and DTE Electric
  
Retail accessMichigan legislation provided customers the option of access to alternative suppliers for electricity and natural gas.
  
RNGRenewable Natural Gas
RSNRemarketable Senior Notes
RTORegional Transmission Organization
SECSecurities and Exchange Commission
  
SecuritizationSGGStonewall Gas Gathering is a midstream natural gas asset located in West Virginia. DTE Electric financed specific stranded costs at lower interest rates through the saleEnergy purchased 55% of rate reduction bonds by a wholly-owned special purpose entity, The Detroit Edison Securitization Funding LLC.SGG in October 2016, and this asset is part of DTE Energy's Gas Storage and Pipelines segment.
  
ShenangoShenango Incorporated is a coke battery plant located in Pittsburgh, PA, that was closed in January 2016 and is included in the Power and Industrial Projects segment.
  
SO2
Sulfur Dioxide
TCJATax Cuts and Jobs Act of 2017
TCJA rate reduction liabilityBeginning January 1, 2018, as a result of the change in the corporate tax rate, DTE Electric and DTE Gas have reduced revenue and recorded an offsetting regulatory liability.
Topic 606FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, as amended
TRIATerrorism Risk Insurance Program Reauthorization Act of 2015
  


DEFINITIONS

TRMA Transitional Reconciliation Mechanism authorized by the MPSC that allows DTE Electric to recover through rates the deferred net incremental revenue requirement associated with the transition of PLD customers to DTE Electric's distribution system.
  
VEBAVoluntary Employees Beneficiary Association
  
VIEVariable Interest Entity
Units of Measurement
  
BcfBillion cubic feet of natural gas
  
BTUHeatBritish thermal unit, heat value (energy content) of fuel
  
kWhKilowatthour of electricity
  
McfMDth/dThousand cubic feet of gasMillion dekatherms per day
  
MMBtuOne million BTU
MMcf/dMillion cubic feet of gas per day
  
MWMegawatt of electricity
  
MWhMegawatthour of electricity


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FILING FORMAT
This combined Form 10-K is separately filed by DTE Energy and DTE Electric. Information in this combined Form 10-K relating to each individual Registrant is filed by such Registrant on its own behalf. DTE Electric makes no representation regarding information relating to any other companies affiliated with DTE Energy other than its own subsidiaries. Neither DTE Energy, nor any of DTE Energy’s other subsidiaries (other than DTE Electric), has any obligation in respect of DTE Electric's debt securities, and holders of such debt securities should not consider the financial resources or results of operations of DTE Energy nor any of DTE Energy’s other subsidiaries (other than DTE Electric and its own subsidiaries (in relevant circumstances)) in making a decision with respect to DTE Electric's debt securities. Similarly, none of DTE Electric nor any other subsidiary of DTE Energy has any obligation in respect of debt securities of DTE Energy. This combined Form 10-K should be read in its entirety. No one section of this combined Form 10-K deals with all aspects of the subject matter of this combined Form 10-K.

FORWARD-LOOKING STATEMENTS
Certain information presented herein includes “forward-looking statements”"forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 with respect to the financial condition, results of operations, and businesses of the Registrants. Words such as “anticipate,” “believe,” “expect,” “projected,” “aspiration,”"anticipate," "believe," "expect," "may," "could," "projected," "aspiration," "plans," and “goals”"goals" signify forward-looking statements. Forward-looking statements are not guarantees of future results and conditions, but rather are subject to numerous assumptions, risks, and uncertainties that may cause actual future results to be materially different from those contemplated, projected, estimated, or budgeted. Many factors may impact forward-looking statements of the Registrants including, but not limited to, the following:
impact of regulation by the EPA, the FERC, the MPSC, the NRC, and for DTE Energy, the CFTC, as well as other applicable governmental proceedings and regulations, including any associated impact on rate structures;
the amount and timing of cost recovery allowed as a result of regulatory proceedings, related appeals, or new legislation, including legislative amendments and retail access programs;
economic conditions and population changes in the Registrants' geographic area resulting in changes in demand, customer conservation, and thefts of electricity and, for DTE Energy, natural gas;
environmental issues, laws, regulations, and the increasing costsoperational failure of remediation and compliance, including actual and potential new federal and state requirements;
health, safety, financial, environmental, and regulatory risks associated with ownership and operation of nuclear facilities;
changes in the cost and availability of coal and other raw materials, purchased power, and natural gas;
volatility in the short-term naturalelectric or gas storage markets impacting third-party storage revenues related to DTE Energy;distribution systems or infrastructure;
impact of volatility of prices in the oil and gas markets on DTE Energy's gas storage and pipelines operations;
impact of volatility in prices in the international steel markets on DTE Energy's power and industrial projects operations;
the risk of a major safety incident;
environmental issues, laws, regulations, and the increasing costs of remediation and compliance, including actual and potential new federal and state requirements;
the cost of protecting assets against, or damage due to, cyber incidents and terrorism;
health, safety, financial, environmental, and regulatory risks associated with ownership and operation of nuclear facilities;
volatility in the short-term natural gas storage markets impacting third-party storage revenues related to DTE Energy;
volatility in commodity markets, deviations in weather, and related risks impacting the results of DTE Energy's energy trading operations;
changes in the cost and availability of coal and other raw materials, purchased power, and natural gas;
advances in technology that produce power or reduce power consumption;
changes in the financial condition of DTE Energy's significant customers and strategic partners;


the potential for losses on investments, including nuclear decommissioning and benefit plan assets and the related increases in future expense and contributions;
access to capital markets and the results of other financing efforts which can be affected by credit agency ratings;
instability in capital markets which could impact availability of short and long-term financing;

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the timing and extent of changes in interest rates;
the level of borrowings;
the potential for increased costs or delays in completion of significant constructioncapital projects;
changes in, and application of, federal, state, and local tax laws and their interpretations, including the Internal Revenue Code, regulations, rulings, court proceedings, and audits;
the effects of weather and other natural phenomena on operations and sales to customers, and purchases from suppliers;
unplanned outages;
the cost of protecting assets against, or damage due to, terrorism or cyber attacks;
employee relations and the impact of collective bargaining agreements;
the risk of a major safety incident at an electric distribution or generation facility and, for DTE Energy, a gas storage, transmission, or distribution facility;
the availability, cost, coverage, and terms of insurance and stability of insurance providers;
cost reduction efforts and the maximization of plant and distribution system performance;
the effects of competition;
changes in and application of accounting standards and financial reporting regulations;
changes in federal or state laws and their interpretation with respect to regulation, energy policy, and other business issues;
contract disputes, binding arbitration, litigation, and related appeals; and
the risks discussed in the Registrants' public filings with the Securities and Exchange Commission.
New factors emerge from time to time. The Registrants cannot predict what factors may arise or how such factors may cause results to differ materially from those contained in any forward-looking statement. Any forward-looking statements speak only as of the date on which such statements are made. The Registrants undertake no obligation to update any forward-looking statement to reflect events or circumstances after the date on which such statement is made or to reflect the occurrence of unanticipated events.

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Part I
Items 1. and 2. Business and Properties
General
In 1995, DTE Energy incorporated in the State of Michigan. DTE Energy's utility operations consist primarily of DTE Electric and DTE Gas. DTE Energy also has three other segments that are engaged in a variety of energy-related businesses.
DTE Electric is a Michigan corporation organized in 1903 and is a wholly-owned subsidiary of DTE Energy. DTE Electric is a public utility engaged in the generation, purchase, distribution, and sale of electricity to approximately 2.2 million customers in southeastern Michigan.
DTE Gas is a Michigan corporation organized in 1898 and is a wholly-owned subsidiary of DTE Energy. DTE Gas is a public utility engaged in the purchase, storage, transportation, distribution, and sale of natural gas to approximately 1.21.3 million customers throughout Michigan and the sale of storage and transportation capacity.
DTE Energy's other businesses are involved in 1) natural gas pipelines, gathering, and storage; 2) power and industrial projects; and 3) energy marketing and trading operations.
DTE Electric and DTE Gas are regulated by the MPSC. Certain activities of DTE Electric and DTE Gas, as well as various other aspects of businesses under DTE Energy are regulated by the FERC. In addition, the Registrants are regulated by other federal and state regulatory agencies including the NRC, the EPA, the MDEQ, and for DTE Energy, the CFTC.
The Registrants' annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, proxy statements, and all amendments to such reports are available free of charge through the Investors -Investor Relations Reports and Filings page of DTE Energy's website: www.dteenergy.com, as soon as reasonably practicable after they are filed with or furnished to the SEC. The Registrants' previously filed reports and statements are also available at the SEC’s website: www.sec.gov.
The DTE Energy Code of Ethics and Standards of Behavior, Board of Directors’ Mission and Guidelines, Board Committee Charters, and Categorical Standards for Director Independence are also posted on the DTE Energy website. The information on DTE Energy’s website is not part of this report or any other report that DTE Energy files with, or furnishes to, the SEC.
Additionally, the public may read and copy any materials the Registrants file with the SEC at the SEC’s Public Reference Room at 100 F Street, NE, Room 1580, Washington, D.C. 20549. The public may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. The SEC also maintains an Internet site that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC at www.sec.gov.
Corporate Structure
Based on the following structure, DTE Energy sets strategic goals, allocates resources, and evaluates performance.performance based on the following structure. For financial information by segment for the last three years, see Note 2022 to the Consolidated Financial Statements in Item 8 of this Report, "Segment and Related Information".Information."
Electric
The Electric segment consists principally of DTE Electric, which is engaged in the generation, purchase, distribution, and sale of electricity to approximately 2.2 million residential, commercial, and industrial customers in southeastern Michigan.
Gas
The Gas segment consists principally of DTE Gas, which is engaged in the purchase, storage, transportation, distribution, and sale of natural gas to approximately 1.21.3 million residential, commercial, and industrial customers throughout Michigan and the sale of gas storage and transportation capacity.

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Non-utility Operations
Gas Storage and Pipelines consists of natural gas pipelines,pipeline, gathering, transportation, and storage businesses.
Power and Industrial Projects is comprised primarily of projects that deliver energy and utility-type products and services to industrial, commercial, and institutional customers, produce reduced emissions fuel, and sell electricity from renewable energy projects.
Energy Trading consists of energy marketing and trading operations.
Corporate and Other
Corporate and otherOther includes various holding company activities, and holds certain non-utility debt, and holds energy-related investments.
orgchart2a03.jpg
Refer to Management’s Discussion and Analysis in Item 7 of this Report for an in-depth analysis of each segment’s financial results. A description of each business unit follows.
ELECTRIC
Description
DTE Energy's Electric segment consists principally of DTE Electric, an electric utility engaged in the generation, purchase, distribution, and sale of electricity to approximately 2.2 million customers in southeastern Michigan. DTE Electric is regulated by numerous federal and state governmental agencies, including, but not limited to, the MPSC, the FERC, the NRC, the EPA, and the MDEQ. Electricity is generated from fossil-fuel plants, a hydroelectric pumped storage plant, a nuclear plant, wind and other renewable assets and is supplemented with purchased power. The electricity is sold, or distributed through the retail access program, to three major classes of customers: residential, commercial, and industrial, throughout southeastern Michigan.
Operating Revenues by Service
 2015 2014 2013
 (In millions)
Residential$2,186
 $2,168
 $2,351
Commercial1,701
 1,761
 1,883
Industrial645
 767
 799
Other (a)281
 494
 45
Subtotal4,813
 5,190
 5,078
Interconnection sales (b)88
 93
 121
Electric segment Operating Revenues$4,901
 $5,283
 $5,199

(a)Includes revenue associated with the under or over recoveries of tracking mechanisms and deferred gain amortization of the previously reversed RDM liability.
(b)Represents power that is not distributed by DTE Electric.

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Weather, economic factors, competition, energy efficiencywaste reduction initiatives, and electricity prices affect sales levels to customers. DTE Electric's peak load and highest total system sales generally occur during the third quarter of the year, driven by air conditioning and other cooling-related demands. DTE Electric's operations are not dependent upon a limited number of customers, and the loss of any one or a few customers would not have a material adverse effect on the results of DTE Electric.
See Note 4 to the Consolidated Financial Statements in Item 8 of the Report, "Revenue."


Fuel Supply and Purchased Power
DTE Electric's power is generated from a variety of fuels and is supplemented with purchased power. DTE Electric expects to have an adequate supply of fuel and purchased power to meet its obligation to serve customers. DTE Electric's generating capability is heavily dependent upon the availability of coal. Coal is purchased from various sources in different geographic areas under agreements that vary in both pricing and terms. DTE Electric expects to obtain the majority of its coal requirements through long-term contracts, with the balance to be obtained through short-term agreements and spot purchases. DTE Electric has long-term and short-term contracts for the purchase of approximately 37.924 million tons of low-sulfur western coal and approximately 3.0 million850 thousand tons of Appalachian coal to be delivered from 20162019 to 2021.2022. All of these contracts have pricing schedules. DTE Electric has approximately 98%86% of the expected coal requirements for 20162019 under contract. Given the geographic diversity of supply, DTE Electric believes it can meet its expected generation requirements. DTE Electric leases a fleet of rail cars and has the expected western and eastern coal rail requirements under contract through 2018. All of the expected eastern coal rail requirements are under contract through 2016.2021. Contracts covering expected vessel transportation requirements for delivery of purchased coal to electric generating facilities are under contract through 2019.
DTE Electric participates in the energy market through MISO. DTE Electric offers its generation in the market on a day-ahead and real-time basis and bids for power in the market to serve its load. DTE Electric is a net purchaser of power that supplements its generation capability to meet customer demand during peak cycles or during major plant outages.


Properties
DTE Electric owns generating facilities that are located in the State of Michigan. Substantially all of DTE Electric's property is subject to the lien of a mortgage.

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Generating facilities owned and in service as of December 31, 20152018 are shown in the following table:
 
Location by
Michigan
 Net Generation Capacity (a) 
Location by
Michigan
County
 
Net Generation Capacity(a)
Facility County Year in Service (MW) Year in Service (MW)
Fossil-fueled Steam-Electric    
Belle River (b) St. Clair 1984 and 1985 1,034
 St. Clair 1984 and 1985 1,034
Greenwood St. Clair 1979 785
 St. Clair 1979 785
Monroe (c) Monroe 1971, 1973, and 1974 3,066
 Monroe 1971, 1973, and 1974 3,066
River Rouge Wayne 1957 and 1958 523
 Wayne 1958 272
St. Clair St. Clair 1953, 1954, 1959, 1961, and 1969 1,367
 St. Clair 1953, 1954, 1961, and 1969 1,216
Trenton Channel Wayne 1949 and 1968 630
 Wayne 1968 495
 7,405
 6,868
Natural gas and Oil-fueled Peaking Units Various 1966-1971, 1981, 1999, 2002, and 2003 2,009
 Various 1966-1971, 1981, 1999, 2002, and 2003 2,033
Nuclear-fueled Steam-Electric Fermi 2 Monroe 1988 1,124
 Monroe 1988 1,141
Hydroelectric Pumped Storage Ludington (d) Mason 1973 958
 Mason 1973 1,054
Renewables (e)    
Wind(f)    
Brookfield Wind Park Huron 2014 75
 Huron 2014 75
Echo Wind Park Huron 2014 112
 Huron 2014 112
Gratiot Wind Park Gratiot 2011 and 2012 102
 Gratiot 2011 and 2012 102
Pinnebog Wind Park Huron 2016 51
Thumb Wind Project Huron and Sanilac 2012 110
 Huron and Sanilac 2012 110
 399
 450
Solar Various 2010-2015 12
  
Utility-Owned SolarCurrents Various 2010-2016 14
Utility Scale Solar Various 2017 50
 11,907
 64
 11,610

(a)Represents summer net rating for all units with the exception of renewable facilities. The summer net rating is based on operating experience, the physical condition of units, environmental control limitations, and customer requirements for steam, which would otherwise be used for electric generation. Wind and solar facilities reflect name plate capacity.capacity measured in alternating current.
(b)TheRepresents DTE Electric's 81% interest in Belle River with a total capability represents DTE Electric’s entitlement to 81% of the capacity and energy of the plant.1,270 MW. See Note 67 to the Consolidated Financial Statements in Item 8 of this Report, "Jointly-Owned Utility Plant".Plant."
(c)The Monroe generating plant provided 40%43% of DTE Electric’s total 20152018 power plant generation.
(d)Represents DTE Electric’s 49% interest in Ludington with a total capability of 1,9552,151 MW. See Note 67 to the Consolidated Financial Statements in Item 8 of this Report, "Jointly-Owned Utility Plant".Plant."
(e)In addition to the owned renewable facilities described above, DTE Electric has long-term contracts for 487481 MW of renewable power generated from wind, solar, and biomass facilities.
(f)In December 2018, DTE Electric acquired the majority of the Pine River Wind Park with a Net Generation Capacity of 161 MW located in Gratiot County, which is expected to be placed into service in the first quarter of 2019.
DTE Electric expects to retire Trenton Channel Unit 7 (110 MW)See "Capital Investments" in April 2016. Over the next fifteen years, DTE Electric expects to retire additional coal-fired generationManagement's Discussion and to increase the proportion of its generation mix attributable to natural gas-fired generation and renewables. DTE Electric acquired two simple-cycle natural gas facilities in 2015. In January 2015, DTE Electric acquired a 732 MW simple-cycle natural gas facility in Carson City, Michigan (Montcalm County) that was placed in service in 2002 and 2003. In October 2015, DTE Electric acquired a 350 MW simple-cycle natural gas facility in East China Township, Michigan (St. Clair County) that was placed in service in 2002. These acquisitions are included in Natural gas and Oil-fueled Peaking Units in the table above. See Note 4 to the Consolidated Financial StatementsAnalysis in Item 87 of this Report "Acquisitionsfor information regarding plant retirements and Exit Activities".future capital expenditures.


DTE Electric owns and operates 676696 distribution substations with a capacity of approximately 33,729,00036,661,000 kilovolt-amperes (kVA) and approximately 432,500442,700 line transformers with a capacity of approximately 23,472,00032,059,000 kVA.

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Circuit miles of electric distribution lines owned and in service as of December 31, 20152018 are shown in the following table:
 Circuit Miles Circuit Miles
Operating Voltage-Kilovolts (kV) Overhead Underground Overhead Underground
4.8 kV to 13.2 kV 27,686
 14,731
 28,498
 15,252
24 kV 182
 692
 182
 686
40 kV 2,290
 383
 2,306
 376
120 kV 60
 8
 61
 8
 30,218
 15,814
 31,047
 16,322
There are numerous interconnections that allow the interchange of electricity between DTE Electric and electricity providers external to the DTE Electric service area. These interconnections are generally owned and operated by ITC Transmission, an unrelated company, and connect to neighboring energy companies.
Regulation
DTE Electric is subject to the regulatory jurisdiction of various agencies, including, but not limited to, the MPSC, the FERC, and the NRC. The MPSC issues orders pertaining to rates, recovery of certain costs, including the costs of generating facilities and regulatory assets, conditions of service, accounting, and operating-related matters. DTE Electric's MPSC-approved rates charged to customers have historically been designed to allow for the recovery of costs, plus an authorized rate of return on investments. The FERC regulates DTE Electric with respect to financing authorization and wholesale electric activities. The NRC has regulatory jurisdiction over all phases of the operation, construction, licensing, and decommissioning of DTE Electric's nuclear plant operations. DTE Electric is subject to the requirements of other regulatory agencies with respect to safety, the environment, and health.
See Notes 7, 8, 11,9, 12, and 1718 to the Consolidated Financial Statements in Item 8 of this Report, "Asset Retirement Obligations",Obligations," "Regulatory Matters",Matters," "Fair Value",Value," and "Commitments and Contingencies".Contingencies."
Energy Assistance Programs
Energy assistance programs, funded by the federal government and the State of Michigan, remain critical to DTE Electric’s ability to control its uncollectible accounts receivable and collections expenses. DTE Electric’s uncollectible accounts receivable expense is directly affected by the level of government-funded assistance that qualifying customers receive. DTE Electric works continuously with the State of Michigan and others to determine whether the share of funding allocated to customers is representative of the number of low-income individuals in the service territory. DTE Electric also partners with federal, state, and local officials to attempt to increase the share of low-income funding allocated to customers.
Strategy and Competition
DTE Electric's electrical generation operations seek to provide the energy needs of customers in a cost effective manner. With potential capacity constraints in the MISO region, there will be increased dependency on DTE Electric's generation to provide reliable service and price stability for customers. This generation will require a large investment due tocontinuing investments in DTE Electric's agingprimary coal fleet along with increased environmental regulations.generating units, a natural gas fueled combined cycle generation facility, and renewables.
DTE Electric's distribution operations focus is on distributing energy in a safe, cost effective, and reliable manner to customers. DTE Electric seeks to increase operational efficiencies to increase customer satisfaction at an affordable rate.


The electric retail access program in Michigan gives electric customers the option of retail access to alternative electric suppliers, subject to limits. Customers with retail access to alternative electric suppliers represented approximately 10% of retail sales in 2015, 2014,2018, 2017, and 20132016 and consisted primarily of industrial and commercial customers. MPSC rate orders and 2008 energy legislation enacted by the State of Michigan have placed a 10% cap on the total retail access related migration, mitigating some of the unfavorable effects of electric retail access on DTE Electric's financial performance and full service customer rates. Energy legislation passed in 2016 retained the 10% retail access cap with some revisions. DTE Electric expects that customers with retail access to alternative electric suppliers will represent approximately 10% of retail sales in 2016.2019.

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Competition in the regulated electric distribution business is primarily from the on-site generation of industrial customers and from distributed generation applications by industrial and commercial customers. DTE Electric does not expect significant competition for distribution to any group of customers in the near term.
Revenues from year to year will vary due to weather conditions, economic factors, regulatory events, and other risk factors as discussed in the “Risk Factors”"Risk Factors" in Item 1A. of this Report.
GAS
Description
DTE Energy's Gas segment consists principally of DTE Gas, a natural gas utility engaged in the purchase, storage, transportation, distribution, and sale of natural gas to approximately 1.21.3 million residential, commercial, and industrial customers throughout Michigan, and the sale of storage and transportation capacity.
Operating Revenues by Service
 2015 2014 2013
 (In millions)
Gas sales$1,019
 $1,233
 $1,093
End-user transportation191
 218
 212
Intermediate transportation59
 68
 59
Storage and other107
 117
 110
Gas segment Operating Revenues$1,376
 $1,636
 $1,474
Gas sales — Includes the sale and delivery of natural gas primarily to residential and small-volume commercial and industrial customers.
End-user transportation — Gas delivery service provided primarily to large-volume commercial and industrial customers. Additionally, the service is provided to residential customers and small-volume commercial and industrial customers who have elected to participate in the gas retail access program. End-user transportation customers purchase natural gas directly from marketers, producers, or brokers and utilize DTE Gas' pipeline network to transport the gas to their facilities or homes.
Intermediate transportation — Gas delivery service is provided to producers, brokers, and other gas companies that own the natural gas, but are not the ultimate consumers. Intermediate transportation customers use DTE Gas' high-pressure transportation system to transport the natural gas to storage fields, pipeline interconnections, or other locations.
Storage and other — Includes revenues from natural gas storage, appliance maintenance, facility development, and other energy-related services.
DTE Gas' gas sales, end-user transportation, and intermediate transportation volumes, revenues, and Net Income, are impacted by weather. Given the seasonal nature of the business, revenues and Net Income are concentrated in the first and fourth quarters of the calendar year. By the end of the first quarter, the heating season is largely over, and DTE Gas typically realizes substantially reduced revenues and earnings in the second quarter, and losses in the third quarter. The impacts of changes in annual average customer usage are minimized by the RDM.
DTE Gas operations are not dependent upon a limited number of customers, and the loss of any one or a few customers would not have a material adverse effect on the results of DTE Gas.
See Note 4 to the Consolidated Financial Statements in Item 8 of the Report, "Revenue."
Natural Gas Supply
DTE Gas' gas distribution system has a planned maximum daily send-out capacity of 2.4 Bcf, with approximately 66% of the volume coming from underground storage for 2015.2018. Peak-use requirements are met through utilization of storage facilities, pipeline transportation capacity, and purchased gas supplies. Because of the geographic diversity of supply and its pipeline transportation and storage capacity, DTE Gas is able to reliably meet supply requirements. DTE Gas believes natural gas supply and pipeline capacity will be sufficiently available to meet market demands in the foreseeable future.

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DTE Gas purchases natural gas supplies in the open market by contracting with producers and marketers, and maintains a diversified portfolio of natural gas supply contracts. Supplier, producing region, quantity, and available transportation diversify DTE Gas' natural gas supply base. Natural gas supply is obtained from various sources in different geographic areas (Gulf(Appalachian, Gulf Coast, Mid-Continent, Canada, and Michigan) under agreements that vary in both pricing and terms. Gas supply pricing is generally tied to the New York Mercantile Exchange and published price indices to approximate current market prices combined with MPSC-approved fixed price supplies with varying terms and volumes through 2018.2021.


DTE Gas is directly connected to interstate pipelines, providing access to most of the major natural gas supply producing regions in the Appalachian, Gulf Coast, Mid-Continent, and Canadian regions. The primary long-term transportation supply contracts at December 31, 20152018 are as follows:listed below.
Availability
(MMcf/d)
 
Contract
Expiration
Availability
(MDth/d)
 
Contract
Expiration
Great Lakes Gas Transmission L.P.30 201730 2022
Viking Gas Transmission Company21 201721 2022
Vector Pipeline L.P.50 2017
Trunkline Gas Company51 2017
Vector Pipeline L.P. (an affiliate)20 2022
ANR Pipeline Company154 2028129 2028
Panhandle Eastern Pipeline Company95 2029125 2029
NEXUS Pipeline (an affiliate)75 2033
Properties
DTE Gas owns distribution, storage, and transportation properties that are located in the State of Michigan. The distribution system includes approximately 19,00019,800 miles of distribution mains, approximately 1,165,0001,305,000 service pipelines, and approximately 1,314,0001,273,000 active meters, and DTE Gas owns approximately 2,000 miles of transmission pipelines that deliver natural gas to the distribution districts and interconnect DTE Gas storage fields with the sources of supply and the market areas.
DTE Gas owns storage properties relating to four underground natural gas storage fields with an aggregate working gas storage capacity of approximately 141139 Bcf. These facilities are important in providing reliable and cost-effective service to DTE Gas customers. In addition, DTE Gas sells storage services to third parties.
Most of DTE Gas' distribution and transportation property is located on property owned by others and used by DTE Gas through easements, permits, or licenses. Substantially all of DTE Gas' property is subject to the lien of a mortgage.
DTE Gas leases a portion of its pipeline system to the Vector Pipeline Partnership (an affiliate) through a capital lease arrangement. See Note 1617 to the Consolidated Financial Statements in Item 8 of the Report, "Capital and Operating Leases".Leases."
Regulation
DTE Gas is subject to the regulatory jurisdiction of the MPSC, which issues orders pertaining to rates, recovery of certain costs, including the costs of regulatory assets, conditions of service, accounting, and operating-related matters. DTE Gas' MPSC-approved rates charged to customers have historically been designed to allow for the recovery of costs, plus an authorized rate of return on investments. DTE Gas operates natural gas storage and transportation facilities in Michigan as intrastate facilities regulated by the MPSC and provides intrastate storage and transportation services pursuant to ana MPSC-approved tariff.
DTE Gas also provides interstate storage and transportation services in accordance with an Operating Statement on file with the FERC. The FERC's jurisdiction is limited and extends to the rates, non-discriminatory requirements, and the terms and conditions applicable to storage and transportation provided by DTE Gas in interstate markets. FERC granted DTE Gas authority to provide storage and related services in interstate commerce at market-based rates. DTE Gas provides transportation services in interstate commerce at cost-based rates approved by the MPSC and filed with the FERC.
DTE Gas is subject to the requirements of other regulatory agencies with respect to safety, the environment, and health.
See Notes 89 and 1718 to the Consolidated Financial Statements in Item 8 of this Report, "Regulatory Matters" and "Commitments and Contingencies".Contingencies."

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Energy Assistance Program
Energy assistance programs, funded by the federal government and the State of Michigan, remain critical to DTE Gas' ability to control its uncollectible accounts receivable and collections expenses. DTE Gas' uncollectible accounts receivable expense is directly affected by the level of government-funded assistance its qualifying customers receive. DTE Gas works continuously with the State of Michigan and others to determine whether the share of funding allocated to customers is representative of the number of low-income individuals in the gas service territory. DTE Gas also partners with federal, state, and local officials to attempt to increase the share of low-income funding allocated to DTE Gas customers.


Strategy and Competition
DTE Gas' strategy is to ensure the safe, reliable, and cost effective delivery of natural gas service within its franchised markets in Michigan. In addition, DTE Gas is promoting the extension of its distribution system to under servedunderserved markets and the increased use of natural gas furnaces, water heaters, and appliances within its current customer base. DTE Gas continues to focus on the reduction of operating costs and the delivery of energy efficiencywaste reduction products and services to its customers, making natural gas service the preferred fuel and even more affordable for its customers.
Competition in the gas business primarily involves other natural gas transportation providers, as well as providers of alternative fuels and energy sources. The primary focus of competition for end-user transportation is cost and reliability. Some large commercial and industrial customers have the ability to switch to alternative fuel sources such as coal, electricity, oil, and steam. If these customers were to choose an alternative fuel source, they would not have a need for DTE Gas' end-user transportation service. DTE Gas competes against alternative fuel sources by providing competitive pricing and reliable service, supported by its storage capacity.
Having an extensive transportation pipeline system has enabled marketing of DTE Gas' storage and transportation services to gas producers, marketers, distribution companies, end-user customers, and other pipeline companies. The business operates in a central geographic location with connections to major Midwestern interstate pipelines that extend throughout the Midwest, eastern United States, and eastern Canada.
DTE Gas' storage capacity is used to store natural gas for delivery to its customers, and is also sold to third parties under a variety of arrangements. Prices for storage arrangements for shorter periods are generally higher, but more volatile, than for longer periods. Prices are influenced primarily by market conditions, weather, and natural gas pricing.
GAS STORAGE AND PIPELINES
Description
Gas Storage and Pipelines controlsowns natural gas storage fields, intrastate lateral and intrastate gathering pipeline systems, compression and surface facilities, and has ownership interests in interstate pipelines serving the Midwest, Ontario, and Northeast markets. The pipeline and storage assets are primarily supported by long-term, fixed-price revenue contracts.
Properties
Gas Storage and Pipelines holds the following properties:
Property Classification % Owned Description Location
Pipelines      
Appalachia Gathering System100%116-mile pipeline delivering Marcellus Shale gas to Texas Eastern Pipeline and Stonewall Gas Gathering systemPA and WV
Birdsboro Pipeline100%14-mile pipeline delivering gas supply to the Birdsboro Power PlantPA
Bluestone Pipeline 100% 53.3-miles of installed64-mile pipeline delivering Marcellus Shale gas to Millennium Pipeline and Tennessee Pipeline PA and NY
Michigan gathering systems 100% Gathers production gas590-mile pipeline system in northern Michigan MI
Millennium Pipeline26%269-mile pipeline serving markets in the NortheastNY
NEXUS Pipeline50%256-mile pipeline to transport Utica and Marcellus shale gas to Ohio, Michigan, and Ontario market centersOH and MI
Stonewall Gas Gathering55%68-mile pipeline connecting Appalachia Gathering System to Columbia PipelineWV
Susquehanna gathering system 100% Gathering system203-mile pipeline delivering Southwestern Energy's Marcellus Shale gas production to Bluestone PipelinePA
Tioga Gas Gathering100%3-mile pipeline delivering production gas to Dominion Transmission interconnect PA
Vector Pipeline 40% 348-mile pipeline connecting Chicago, Michigan, and Ontario market centers IL, IN, MI, and Ontario
Millennium Pipeline26%182-mile pipeline serving markets in the NortheastNY
Storage      
Washington 10 100% 75 Bcf of storage capacity MI
Washington 28 50% 16 Bcf of storage capacity MI

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The assets of these businesses are well integrated with other DTE Energy operations. Pursuant to an operating agreement, DTE Gas provides physical operations, maintenance, and technical support for the Washington 10 and 28 storage facilities and for the Michigan gathering systems.
In addition, DTE Energy owns a 50% interest in the NEXUS Pipeline, a proposed 255-mile pipeline to transport Utica and Marcellus shale gas to Ohio, Michigan and Ontario market centers. A FERC application was filed in the fourth quarter of 2015 with an estimated in service date in the fourth quarter of 2017.
Regulation
Gas Storage and Pipelines operates natural gas storage facilities in Michigan as intrastate facilities regulated by the MPSC, and provides intrastate storage and related services pursuant to an MPSC-approved tariff. Gas Storage and Pipelines also provides interstate services in accordance with an Operating Statement on file with the FERC. Vector, Millennium, Birdsboro, and MillenniumNEXUS Pipelines provide interstate transportation services in accordance with their FERC-approved tariffs. In addition, NEXUS and Vector isare subject to applicable laws, rules, and regulations in Canada. NEXUS Pipeline, when operational, will also provide interstate transportation services in accordance with their FERC-approved tariffs. In Pennsylvania, Gas Storage and Pipelines' gathering and pipeline assets are subject to the rules and regulations of the Pennsylvania Public Utility Commission. Bluestone Pipeline is regulated in thevarious state of New York by the New York Public Service Commission.utility commissions.
Strategy and Competition
Gas Storage and Pipelines expects to continue its steady growth plan by expanding existing assets, acquiring and/or developing new assets that are typically supported with long-term customer commitments. Gas Storage and Pipelines has competition from other pipelines and storage providers. The focus will be on opportunities in the Midwest to Northeast region to supply natural gas to meet growing demand.demand and displace less attractive supply from certain regions in North America. Much of the growth in demand for natural gas is expected to occur in the Easterneastern Canada and the Northeastnortheast U.S. regions. Gas Storage and Pipelines believes that the Vector, Millennium, and MillenniumNEXUS Pipelines are well positioned to provide access routes and low-cost expansion options to these markets. In addition, Gas Storage and Pipelines believes that Millennium Pipeline is well positioned formarkets due to growth in production from the Marcellus Shale, especially with respect to Marcellus productionMarcellus/Utica Shales in Northern Pennsylvania.Pennsylvania and West Virginia. Gas Storage and Pipelines has an agreementagreements with Southwestern Energy Production Company tokey producers that support its Bluestone Pipeline, and Susquehanna gathering, system. DTE Energy expects to continue steady growth in theTioga gathering, AGS, and SGG businesses. Gas Storage and Pipelines business and is evaluating new pipeline and storage investment opportunities that could include additional Millenniumpipeline and Vectorgathering expansions, and laterals, Bluestone compression, and laterals, Susquehanna gathering expansions, and other Marcellus/Utica shale midstream development or partnering opportunities, such as the NEXUS Pipeline. opportunities.
Gas Storage and Pipelines' operationsPipelines has competition from other pipelines and storage providers. Operations are dependent upon a limited number of customers, and the loss of any one or a few customers could have a material adverse effect on the results of Gas Storage and Pipelines.
POWER AND INDUSTRIAL PROJECTS
Description
Power and Industrial Projects is comprised primarily of projects that deliver energy and utility-type products and services to industrial, commercial, and institutional customers, produce reduced emissions fuel, and sell electricity and gas from renewable energy projects. This business segment provides services using project assets usually located on or near the customers' premises in the steel, automotive, pulp and paper, airport, chemical, and other industries as follows:
Industrial Energy Services
Steel and Petroleum Coke —Power and Industrial Projects produces metallurgical coke from onea coke battery with a capacity of 1.0 million tons per year and has an investment in a second coke battery with a capacity of 1.2 million tons per year. Power and Industrial Projects also provides pulverized coal and petroleum coke to the steel, pulp and paper, and other industries.
On-Site Energy —Power and Industrial Projects provides power generation, steam production, chilled water production, wastewater treatment, and compressed air supply to industrial customers. Power and Industrial Projects also provides utility-type services using project assets usually located on or near the customers' premises in the automotive, airport, chemical, and other industries.

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Renewable Energy
Wholesale Power and Renewables —Power and Industrial Projects holds ownership interests in, and operates, fourfive renewable generating plants with a capacity of 191217 MWs. The electric output is sold under long-term power purchase agreements.
Renewable Gas Recovery — Power and Industrial Projects also develops landfillhas ownership interests in, and operates, twenty-three gas recovery systems that capturesites in nine different states. The sites recover methane from landfills and agricultural businesses and convert the gas to generate electricity, replace fossil fuels in industrial and provide local utilities, industries, and consumers with an opportunitymanufacturing operations, or refine to use a competitive, renewable source of energy, in addition to providing environmental benefits by reducing GHG emissions.pipeline-quality gas, which can then be used as vehicle fuel.
Reduced Emissions Fuel
Reduced Emissions Fuel — Power and Industrial Projects has constructed and placed in service REF facilities at nineten sites including facilities located at sixseven third-party owned coal-fired power plants. DTE Energy has sold membership interests in fourfive of the facilities and entered into lease arrangements at twoin three of the facilities. DTE Energy will continue to optimize these facilities by seeking investors or entering into lease arrangements for facilities operating at DTE Electric and other utility sites. DTE Energy is in the process of relocating an underutilized facility at an existing site to a new third-party owned coal-fired power plant. In addition, DTE Energy has entered into an agreement to operate an REF facility owned by an outside party located at a third-party owned coal-fired power plant. The facilities blend a proprietary additive with coal used in coal-fired power plants, resulting in reduced emissions of nitrogen oxide and mercury. Qualifying facilities are eligible to generate tax credits for ten years upon achieving certain criteria. The value of a tax credit is adjusted annually by an inflation factor published by the IRS. The value of the tax credit is reduced if the reference price of coal exceeds certain thresholds. The economic benefit of the REF facilities is dependent upon the generation of production tax credits.
Properties and Other
The following are significant properties operated by Power and Industrial Projects:
FacilityBusiness Areas Location Service Type
Industrial Energy Services
Steel and Petroleum Coke    
Pulverized Coal Operations MI Pulverized Coal
Coke Production MI Metallurgical Coke Supply
Other Investment in Coke Production and Petroleum Coke IN and MS Metallurgical Coke Supply and Pulverized Petroleum Coke
On-Site Energy    
Automotive Various sites inIN, MI, IN,NY, and OH and NY Electric Distribution, Chilled Water, Waste Water, Steam, Cooling Tower Water, Reverse Osmosis Water, Compressed Air, Mist, and Dust Collectors
Airports MI and PA Electricity and Hot and Chilled Water
Chemical Manufacturing IL, KY and OH Electricity, Steam, Natural Gas, Compressed Air, and Wastewater
Consumer Manufacturing OH Electricity, Steam, Wastewater, and Sewer
Business Park PA Electricity
Hospital and University CA and IL Electricity, Steam, and Chilled Water
Wholesale Power and RenewablesRenewable Energy    
Pulp and Paper AL Electric Generation and Steam
Renewables CA and MN Electric Generation
LandfillRenewable Gas Recovery Various U.S. sitesAZ, CA, MI, NC, NY, OH, TX, UT, and WI Electric Generation and LandfillRenewable Natural Gas
REFReduced Emissions Fuel MI, OH, OK, IL, PA, TX, and WI REF Supply


2015 2014 20132018 2017 2016
(In millions)(In millions)
Production Tax Credits Generated (Allocated to DTE Energy)          
REF$77
 $84
 $44
$178
 $144
 $103
Power Generation11
 11
 8
Landfill Gas Recovery3
 2
 1
Renewables7
 6
 8
Renewable Gas Recovery3
 3
 3
$91
 $97
 $53
$188
 $153
 $114

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Regulation
Certain electric generating facilities within Power and Industrial Projects have market-based rate authority from the FERC to sell power. The facilities are subject to FERC reporting requirements and market behavior rules. Certain projects of Power and Industrial Projects are also subject to the applicable laws, rules, and regulations related to the EPA, U.S. Department of Homeland Security, DOE, and various state utility commissions.
Strategy and Competition
Power and Industrial Projects will continue leveraging its energy-related operating experience and project management capability to develop and grow its steel, on-site energy, and renewable power,energy businesses, and optimize the REF businesses. Power and Industrial Projects will also continue to pursue opportunities to provide asset management and operations services to third parties. There are limited competitors for Power and Industrial Projects' existing disparate businesses who provide similar products and services. Power and Industrial Projects' operations are dependent upon a limited number of customers, and the loss of any one or a few customers could have a material adverse effect on the results of Power and Industrial Projects.
Power and Industrial Projects anticipates building around its core strengths in the markets where it operates. In determining the markets in which to compete, Power and Industrial Projects examines closely the regulatory and competitive environment, new and pending legislation, the number of competitors, and its ability to achieve sustainable margins. Power and Industrial Projects plans to maximize the effectiveness of its related businesses as it expands. As Power and Industrial Projects pursues growth opportunities, the first priority will be to achieve value-added returns.
Power and Industrial Projects intends to focus on the following areas for growth:
Obtaining investors in the REF projects;
Relocating underutilized REF facilitiesProviding operating services to alternative coal-firedowners of on-site industrial power plants which may provide increased production and emission reduction opportunities in 2016 and future years;plants;
Acquiring and developing landfillrenewable gas recovery facilities, renewable energy projects, and other energy projects which may qualify for tax credits; and
Providing operating services to owners of on-site industrial and power plants.projects.
ENERGY TRADING
Description
Energy Trading focuses on physical and financial power and gas marketing and trading, structured transactions, enhancement of returns from its asset portfolio and optimization of contracted natural gas pipeline transportation, and storage positions. Energy Trading also provides natural gas, power, and related services which may include the management of associated storage and transportation contracts on the customers’ behalf and the supply or purchase of renewable energy credits to various customers. Energy Trading's customer base is predominantly utilities, local distribution companies, pipelines, producers and generators, and other marketing and trading companies. Energy Trading enters into derivative financial instruments as part of theirits marketing and hedging activities. These financial instruments are generally accounted for under the MTM method, which results in the recognition in earnings of unrealized gains and losses from changes in the fair value of the derivatives. Energy Trading utilizes forwards, futures, swaps, and option contracts to mitigate risk associated with marketing and trading activity, as well as for proprietary trading within defined risk guidelines. Energy Trading also provides commodity risk management services to the other businesses within DTE Energy.
Significant portions of the Energy Trading portfolio are economically hedged. Most financial instruments and physical power and natural gas contracts are deemed derivatives; whereas, natural gas inventory, contracts for pipeline transportation, renewable energy credits, and storage assets are not derivatives. As a result, this segment will experience earnings volatility as derivatives are marked-to-market without revaluing the underlying non-derivative contracts and assets. The business’ strategy is to economically manage the price risk of these underlying non-derivative contracts and assets with futures, forwards, swaps, and options. This results in gains and losses that are recognized in different interim and annual accounting periods.

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Regulation
Energy Trading has market-based rate authority from the FERC to sell power and blanket authority from the FERC to sell natural gas at market prices. Energy Trading is subject to FERC reporting requirements and market behavior rules. Energy Trading is also subject to the applicable laws, rules, and regulations related to the CFTC, U.S. Department of Homeland Security, and DOE. In addition, Energy Trading is subject to applicable laws, rules, and regulations in Canada.
Strategy and Competition
DTE Energy's strategy for the Energy Trading business is to deliver value-added services to DTE Energy customers. DTE Energy seeks to manage this business in a manner complementary to the growth of DTE Energy's other business segments. Energy Trading focuses on physical marketing and the optimization of its portfolio of energy assets. The segment competes with electric and gas marketers, financial institutions, traders, utilities, and other energy providers. The Energy Trading business is dependent upon the availability of capital and an investment grade credit rating. DTE Energy believes it has ample available capital capacity to support Energy Trading activities. DTE Energy monitors its use of capital closely to ensure that its commitments do not exceed capacity. A material credit restriction would negatively impact Energy Trading's financial performance. Competitors with greater access to capital, or at a lower cost, may have a competitive advantage. DTE Energy has risk management and credit processes to monitor and mitigate risk.
CORPORATE AND OTHER
Description
Corporate and Other includes various holding company activities, holds certain non-utility debt, and holds energy-related investments.
ENVIRONMENTAL MATTERS
The Registrants are subject to extensive environmental regulation and expect to continue recovering environmental costs related to utility operations through rates charged to customers. The following table summarizes DTE Energy's, including DTE Electric's, estimated significant future environmental expenditures based upon current regulations. Pending or future reconsiderations of current regulations may impact the estimated expenditures summarized in the table below. The amounts reported in the table do not include any expenditures related to the EPA Clean Power Plan that has been stayed as discussed below. Actual costs to comply could vary substantially. Additional costs may result as the effects of various substances on the environment are studied and governmental regulations are developed and implemented.
 DTE Electric DTE Gas Non-utility Total
 (In millions)
Water$60
 $
 $
 $60
Contaminated and other sites10
 25
 
 35
Coal combustion residuals and effluent limitations guidelines515
 
 
 515
Estimated total future expenditures through 2025$585
 $25
 $
 $610
Estimated 2019 expenditures$30
 $15
 $
 $45
Estimated 2020 expenditures$60
 $5
 $
 $65
Water — The EPA finalized regulations on cooling water intake in August 2014. DTE Electric is conducting studies to determine the best technology for reducing the environmental impacts of the cooling water intake structures at each of its facilities. DTE Electric may be required to install technologies to reduce the impacts of the cooling water intakes.
Contaminated and Other Sites — Prior to the construction of major interstate natural gas pipelines, gas for heating and other uses was manufactured locally from processes involving coal, coke, or oil. The facilities, which produced gas, have been designated as MGP sites. DTE Gas owns, or previously owned, 14 such former MGP sites. DTE Electric owns, or previously owned, three former MGP sites. DTE Energy anticipates the cost amortization methodology approved by the MPSC for DTE Gas, which allows DTE Gas to amortize the MGP costs over a ten-year period beginning with the year subsequent to the year the MGP costs were incurred, will prevent environmental costs from having a material adverse effect on DTE Energy's operations. DTE Electric believes the likelihood of a material change to the accrued amount is remote based on current knowledge of the conditions at each site.


The Registrants are also in the process of cleaning up other sites where contamination is present as a result of historical and ongoing utility operations. These other sites include an engineered ash storage facility, electric distribution substations, gas pipelines, electric generating power plants, and underground and aboveground storage tank locations. Cleanup activities associated with these sites will be conducted over the next several years. Any significant change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for these sites and affect the Registrants' financial position and cash flows and the rates charged to their customers.
Coal Combustion Residuals and Effluent Limitations Guidelines — In April 2015, the EPA published a final rule for the disposal of coal combustion residuals, commonly known as coal ash. The rule became effective in October 2015. The rule is based on the continued listing of coal ash as a non-hazardous waste and relies on various self-implementation design and performance standards. DTE Electric owns and operates three permitted engineered coal ash storage facilities to dispose of coal ash from coal-fired power plants and operates a number of smaller impoundments at its power plants. At certain facilities, the rule requires the installation of monitoring wells, compliance with groundwater standards, and the closure of basins at the end of the useful life of the associated power plant. At other facilities, the rule requires ash laden waters be moved from earthen basins to steel and concrete tanks. In 2018, DTE Electric updated its estimated expenditures to remediate accordingly. On October 12, 2018, a D.C. District Court decision became effective that may affect the timing of closure of coal ash impoundments that are not lined with an engineered liner system. In 2019, the EPA is expected to affirmatively undertake rulemaking to implement the D.C. District Court's decision that will determine any changes to DTE Electric's plans in the operations and closure of coal ash impoundments.
In November 2015, the EPA finalized effluent limitations guidelines for the steam electric power generating industry which requires additional controls to be installed between 2018 and 2023. The initial costs to comply with this rule are under development and estimates are included in the Coal Combustion Residual and Effluent Limitations Guidelines amount in the above table.
On April 12, 2017, the EPA granted a petition for reconsideration of the ELG Rule. The EPA also signed an administrative stay of the ELG Rule’s compliance deadlines for fly ash transport water, bottom ash transport water, and flue gas desulfurization (FGD) wastewater, among others. On June 6, 2017, the EPA published in the Federal Register a proposed rule to postpone certain applicable deadlines within the ELG rule. The final rule was published on September 18, 2017. The final rule nullified the administrative stay but also extended the earliest compliance deadlines for the FGD wastewater and bottom ash transport water until November 1, 2020 in order for the EPA to propose and finalize a new ruling. The ELG compliance requirements and final deadlines for bottom ash transport water and FGD wastewater, and total ELG related compliance costs will not be known until the EPA completes its reconsideration of the ELG Rule.
Air — DTE Electric is subject to the EPA ozone and fine particulate transport, and acid rain regulations that limit power plant emissions of SO2 and NOX. The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to emission controls on fossil-fueled power plants to reduce SO2, NOX, mercury, and other emissions. These rulemakings could require additional controls for SO2, NOX, and other hazardous air pollutants over the next few years. DTE Electric does not anticipate additional capital expenditures to comply with air pollution requirements through 2025, pending the results of future rulemakings.
The EPA has implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, the EPA has finalized performance standards for emissions of carbon dioxide from new and existing fossil-fuel EGUs. In February 2016, the U.S. Supreme Court granted petitioners' requests for a stay of the carbon rules for existing EGUs (also known as the EPA Clean Power Plan) pending final review by the courts. The Clean Power Plan has no legal effect while the stay is in place. In October 2017, the EPA issued a proposal to repeal the Clean Power Plan, and in August 2018 the EPA issued its proposed Affordable Clean Energy rule to replace the Clean Power Plan. In addition, in December 2018, the EPA issued proposed revisions to the carbon dioxide standards for new, modified or reconstructed fossil-fuel fired EGUs. The carbon dioxide standard for new sources are not expected to have a material impact on DTE Electric, since DTE Electric has no plans to build new coal-fired generation and any potential new gas generation will be able to comply with the standards. These proposed rules do not impact DTE Energy's goal to reduce carbon emissions 30% by the early 2020s, 45% by 2030, 75% by 2040, and more than 80% by 2050.


Pending or future legislation or other regulatory actions could have a material impact on DTE Electric's operations and financial position and the rates charged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. DTE Electric would seek to recover these incremental costs through increased rates charged to its utility customers, as authorized by the MPSC.
See Management’s Discussion and Analysis in Item 7 of this Report and Notes 8, 9, and 18 to the Consolidated Financial Statements in Item 8 of this Report, "Asset Retirement Obligations," "Regulatory Matters," and "Commitments and Contingencies."
EMPLOYEES
DTE Energy and its subsidiaries had approximately 10,600 employees as of December 31, 2018, of which approximately 5,200 were represented by unions. DTE Electric had approximately 4,900 employees as of December 31, 2018, of which approximately 2,800 were represented by unions. There are several bargaining units for DTE Energy subsidiaries' represented employees. The majority of represented employees for both DTE Energy and DTE Electric are under contracts that expire in 2020 and 2021.

Item 1A. Risk Factors
There are various risks associated with the operations of the Registrants' utility businesses and DTE Energy's non-utility businesses. To provide a framework to understand the operating environment of the Registrants, below is a brief explanation of the more significant risks associated with their businesses. Although the Registrants have tried to identify and discuss key risk factors, others could emerge in the future. Each of the following risks could affect performance.
The Registrants are subject to rate regulation. Electric and gas rates for the utilities are set by the MPSC and the FERC and cannot be changed without regulatory authorization. The Registrants may be negatively impacted by new regulations or interpretations by the MPSC, the FERC, or other regulatory bodies. The Registrants' ability to recover costs may be impacted by the time lag between the incurrence of costs and the recovery of the costs in customers' rates. Regulators also may decide to disallow recovery of certain costs in customers' rates if they determine that those costs do not meet the standards for recovery under current governing laws and regulations. Regulators may also disagree with the Registrants' rate calculations under the various mechanisms that are intended to mitigate the risk to their utilities related to certain aspects of the business. If the Registrants cannot agree with regulators on an appropriate reconciliation of those mechanisms, it may impact the Registrants' ability to recover certain costs through customer rates. Regulators may also decide to eliminate these mechanisms in future rate cases, which may make it more difficult for the Registrants to recover their costs in the rates charged to customers. The Registrants cannot predict what rates the MPSC will authorize in future rate cases. New legislation, regulations, or interpretations could change how the business operates, impact the Registrants' ability to recover costs through rates or the timing of such recovery, or require the Registrants to incur additional expenses.
Changes to Michigan's electric retail access program could negatively impact the Registrants' financial performance. The State of Michigan currently experiences a hybrid market, where the MPSC continues to regulate electric rates for DTE Electric customers, while alternative electric suppliers charge market-based rates. MPSC rate orders, and energy legislation enacted by the State of Michigan, have placed a 10% cap on the total potential retail access migration. However, even with the legislated 10% cap on participation, there continues to be legislative and financial risk associated with the electric retail access program. Electric retail access migration is sensitive to market price and full service electric price changes. The Registrants are required under current regulation to provide full service to retail access customers that choose to return, potentially resulting in the need for additional generating capacity.


The Registrants' electric distribution system and DTE Energy's gas distribution system are subject to risks from their operation, which could reduce revenues, increase expenses, and have a material adverse effect on their business, financial position, and results of operations. The Registrants' electric distribution and DTE Energy’s gas distribution systems are subject to many operational risks. These operational systems and infrastructure have been in service for many years. Equipment, even when maintained in accordance with good utility practices, is subject to operational failure, including events that are beyond the Registrants' control, and could require significant operation and maintenance expense or capital expenditures to operate efficiently. Because the Registrants’ distribution systems are interconnected with those of third parties, the operation of the Registrants’ systems could be adversely affected by unexpected or uncontrollable events occurring on the systems of such third parties.
DTE Energy's non-utility businesses may not perform to its expectations. DTE Energy relies on non-utility operations for an increasing portion of earnings. If DTE Energy's current and contemplated non-utility investments do not perform at expected levels, DTE Energy could experience diminished earnings and a corresponding decline in shareholder value.
DTE Energy relies on cash flows from subsidiaries. DTE Energy is a holding company. Cash flows from the utility and non-utility subsidiaries are required to pay interest expenses and dividends on DTE Energy debt and securities. Should a major subsidiary not be able to pay dividends or transfer cash flows to DTE Energy, its ability to pay interest and dividends would be restricted.
The Registrants' businesses have safety risks. The Registrants' electric distribution system, power plants, renewable energy equipment, and other facilities, and DTE Energy's gas distribution system, gas infrastructure, and other facilities, could be involved in incidents that result in injury, death, or property loss to employees, customers, third parties, or the public. Although the Registrants have insurance coverage for many potential incidents, depending upon the nature and severity of any incident, they could experience financial loss, damage to their reputation, and negative consequences from regulatory agencies or other public authorities.
Environmental laws and liability may be costly. The Registrants are subject to, and affected by, numerous environmental regulations. These regulations govern air emissions, water quality, wastewater discharge, and disposal of solid and hazardous waste. Compliance with these regulations can significantly increase capital spending, operating expenses, and plant down times, and can negatively affect the affordability of the rates charged to customers.
Uncertainty around future environmental regulations creates difficulty planning long-term capital projects in the Registrants' generation fleet and, for DTE Energy's gas distribution businesses. These laws and regulations require the Registrants to seek a variety of environmental licenses, permits, inspections, and other regulatory approvals. The Registrants could be required to install expensive pollution control measures or limit or cease activities, including the retirement of certain generating plants, based on these regulations. Additionally, the Registrants may become a responsible party for environmental cleanup at sites identified by a regulatory body. The Registrants cannot predict with certainty the amount and timing of future expenditures related to environmental matters because of the difficulty of estimating cleanup costs. There is also uncertainty in quantifying liabilities under environmental laws that impose joint and several liability on potentially responsible parties.
The Registrants may also incur liabilities as a result of potential future requirements to address climate change issues. Proposals for voluntary initiatives and mandatory controls are being discussed both in the United States and worldwide to reduce GHGs such as carbon dioxide, a by-product of burning fossil fuels. If increased regulations of GHG emissions are implemented, the operations of DTE Electric's fossil-fueled generation assets may be significantly impacted. Since there can be no assurances that environmental costs may be recovered through the regulatory process, the Registrants' financial performance may be negatively impacted as a result of environmental matters.
For DTE Energy, future environmental regulation of natural gas extraction techniques, including hydraulic fracturing, being discussed both at the United States federal level and by some states may affect the profitability of natural gas extraction businesses which could affect demand for, and profitability of, DTE Energy's gas transportation businesses.
Threats of cyber incidents, physical security, and terrorism could affect the Registrants' business. Issues may threaten the Registrants such as cyber incidents, physical security, or terrorism that may disrupt the Registrants' operations, and could harm the Registrants' operating results.


Information security risks have increased in recent years as a result of the proliferation of new technologies and the increased sophistication and frequency of cyberattacks, and data security breaches. The Registrants' industry requires the continued operation of sophisticated information and control technology systems and network infrastructure. Despite implementation of security measures, all of the Registrants' technology systems are vulnerable to disability or failures due to cyber incidents, physical security threats, acts of war or terrorism, and other causes, as well as loss of operational control of the Registrants' electric generation and distribution assets and, DTE Energy's gas distribution assets. If the Registrants' information technology systems were to fail and they were unable to recover in a timely way, the Registrants may be unable to fulfill critical business functions, which could have a material adverse effect on the Registrants' business, operating results, and financial condition.
Suppliers, vendors, contractors, and information technology providers have access to systems that support the Registrants’ operations and maintain customer and employee data.  A breach of these third-party systems could adversely affect the business as if it was a breach of our own system.  Also, because the Registrants’ generation and distribution systems are part of an interconnected system, a disruption caused by a cyber incident at another utility, electric generator, system operator, or commodity supplier could also adversely affect the Registrants’ businesses, operating results, and financial condition.
In addition, the Registrants' generation plants and electrical distribution facilities, and DTE Energy's gas pipeline and storage facilities, in particular, may be targets of physical security threats or terrorist activities that could disrupt the Registrants' ability to produce or distribute some portion of their products. The Registrants have increased security as a result of past events and may be required by regulators or by the future threat environment to make investments in security that the Registrants cannot currently predict.
Failure to maintain the security of personally identifiable information could adversely affect the Registrants. In connection with the Registrants' businesses, they collect and retain personally identifiable information of their customers, shareholders, and employees. Customers, shareholders, and employees expect that the Registrants will adequately protect their personal information. The regulatory environment surrounding information security and privacy is increasingly demanding. A significant theft, loss, or fraudulent use of customer, shareholder, employee, or Registrant data by cybercrime or otherwise, could adversely impact the Registrants' reputation, and could result in significant costs, fines, and litigation.
Construction and capital improvements to the Registrants' power facilities, DTE Energy's distribution systems and its Gas Storage and Pipelines business subject them to risk. The Registrants are managing ongoing, and planning future, significant construction and capital improvement projects at the Registrants' multiple power generation and distribution facilities, at DTE Energy's gas distribution system, and at DTE Energy's Gas Storage and Pipelines business. Many factors that could cause delays or increased prices for these complex projects are beyond the Registrants' control, including the cost of materials and labor, subcontractor performance, timing and issuance of necessary permits or approvals (including required certificates from regulatory agencies), construction disputes, impediments to acquiring rights-of-way or land rights on a timely basis and on acceptable terms, cost overruns, and weather conditions. Failure to complete these projects on schedule and on budget for any reason could adversely affect the Registrants' financial performance, operations, or expected investment returns at the affected facilities, businesses and development projects.
Operation of a nuclear facility subjects the Registrants to risk. Ownership of an operating nuclear generating plant subjects the Registrants to significant additional risks. These risks include, among others, plant security, environmental regulation and remediation, changes in federal nuclear regulation, increased capital expenditures to meet industry requirements, and operational factors that can significantly impact the performance and cost of operating a nuclear facility compared to other generation options. Insurance maintained by the Registrants for various nuclear-related risks may not be sufficient to cover the Registrants' costs in the event of an accident or business interruption at the nuclear generating plant, which may affect the Registrants' financial performance. In addition, the Registrants' nuclear decommissioning trust fund, to finance the decommissioning of the nuclear generating plant, may not be sufficient to fund the cost of decommissioning. A decline in market value of assets held in decommissioning trust funds due to poor investment performance or other factors may increase the funding requirements for these obligations. Any increase in funding requirements may have a material impact on the Registrants’ liquidity, financial position, or results of operations.


The supply and/or price of energy commodities and/or related services may impact the Registrants' financial results. The Registrants are dependent on coal for much of their electrical generating capacity as well as uranium for their nuclear operations. DTE Energy's access to natural gas supplies is critical to ensure reliability of service for utility gas customers. DTE Energy's non-utility businesses are also dependent upon supplies and prices of energy commodities and services. Price fluctuations, fuel supply disruptions, and changes in transportation costs, could have a negative impact on the amounts DTE Electric charges utility customers for electricity and DTE Gas charges utility customers for gas, and on the profitability of DTE Energy's non-utility businesses. The Registrants' hedging strategies and regulatory recovery mechanisms may be insufficient to mitigate the negative fluctuations in commodity supply prices in their utility and, for DTE Energy, non-utility businesses, and the Registrants' financial performance may therefore be negatively impacted by price fluctuations. The price of energy also impacts the market for DTE Energy's non-utility businesses that compete with utilities and alternative electric suppliers.
The supply and/or price of other industrial raw and finished inputs and/or related services may impact the Registrants' financial results. The Registrants are dependent on supplies of certain commodities, such as copper and limestone, among others, and industrial materials, and services in order to maintain day-to-day operations and maintenance of their facilities. Price fluctuations, or supply interruptions for these commodities and other items, could have a negative impact on the amounts charged to customers for the Registrants' utility products and, for DTE Energy, on the profitability of the non-utility businesses.
Emerging technologies may have a material adverse effect on the Registrants. Advances in technology that produce power or reduce power consumption include cost-effective renewable energy technologies, distributed generation, energy waste reduction technologies, and energy storage devices. Such developments may impact the price of energy, may affect energy deliveries as customer-owned generation becomes more cost-effective, may require further improvements to our distribution systems to address changing load demands, and could make portions of our electric system power supply and/or distribution facilities obsolete prior to the end of their useful lives. Such technologies could also result in further declines in commodity prices or demand for delivered energy. Each of these factors could materially affect the Registrants’ results of operations, cash flows, or financial position.
Adverse changes in the Registrants' credit ratings may negatively affect them. Regional and national economic conditions, increased scrutiny of the energy industry and regulatory changes, as well as changes in the Registrants' economic performance, could result in credit agencies reexamining their credit ratings. While credit ratings reflect the opinions of the credit agencies issuing such ratings and may not necessarily reflect actual performance, a downgrade in the Registrants' credit ratings below investment grade could restrict or discontinue their ability to access capital markets and could result in an increase in their borrowing costs, a reduced level of capital expenditures, and could impact future earnings and cash flows. In addition, a reduction in the Registrants' credit ratings may require them to post collateral related to various physical or financially settled contracts for the purchase of energy-related commodities, products, and services, which could impact their liquidity.
Poor investment performance of pension and other postretirement benefit plan assets and other factors impacting benefit plan costs could unfavorably impact the Registrants' liquidity and results of operations. The Registrants' costs of providing non-contributory defined benefit pension plans and other postretirement benefit plans are dependent upon a number of factors, such as the rates of return on plan assets, the level of interest rates used to measure the required minimum funding levels of the plans, future government regulation, and the Registrants' required or voluntary contributions made to the plans. The performance of the debt and equity markets affects the value of assets that are held in trust to satisfy future obligations under the Registrants' plans. The Registrants have significant benefit obligations and hold significant assets in trust to satisfy these obligations. These assets are subject to market fluctuations and will yield uncertain returns, which may fall below the Registrants' projected return rates. A decline in the market value of the pension and other postretirement benefit plan assets will increase the funding requirements under the pension and other postretirement benefit plans if the actual asset returns do not recover these declines in the foreseeable future. Additionally, the pension and other postretirement benefit plan liabilities are sensitive to changes in interest rates. If interest rates decrease, the liabilities increase, resulting in increasing benefit expense and funding requirements. Also, if future increases in pension and other postretirement benefit costs as a result of reduced plan assets are not recoverable from the Registrants' utility customers, the results of operations and financial position of the Registrants could be negatively affected. Without sustained growth in the plan investments over time to increase the value of plan assets, the Registrants could be required to fund these plans with significant amounts of cash. Such cash funding obligations could have a material impact on the Registrants' cash flows, financial position, or results of operations.


The Registrants' ability to access capital markets is important. The Registrants' ability to access capital markets is important to operate their businesses and to fund capital investments. Turmoil in credit markets may constrain the Registrants' ability, as well as the ability of their subsidiaries, to issue new debt, including commercial paper, and refinance existing debt at reasonable interest rates. In addition, the level of borrowing by other energy companies, and the market as a whole, could limit the Registrants' access to capital markets. The Registrants' long-term revolving credit facilities do not expire until 2022, but the Registrants regularly access capital markets to refinance existing debt or fund new projects at the Registrants' utilities and DTE Energy's non-utility businesses, and the Registrants cannot predict the pricing or demand for those future transactions.
DTE Energy's participation in energy trading markets subjects it to risk. Events in the energy trading industry have increased the level of scrutiny on the energy trading business and the energy industry as a whole. In certain situations, DTE Energy may be required to post collateral to support trading operations, which could be substantial. If access to liquidity to support trading activities is curtailed, DTE Energy could experience decreased earnings potential and cash flows. Energy trading activities take place in volatile markets and expose DTE Energy to risks related to commodity price movements, deviations in weather, and other related risks. DTE Energy's trading business routinely has speculative trading positions in the market, within strict policy guidelines DTE Energy sets, resulting from the management of DTE Energy's business portfolio. To the extent speculative trading positions exist, fluctuating commodity prices can improve or diminish DTE Energy's financial results and financial position. DTE Energy manages its exposure by establishing and enforcing strict risk limits and risk management procedures. During periods of extreme volatility, these risk limits and risk management procedures may not work as planned and cannot eliminate all risks associated with these activities.
Weather significantly affects operations. At both utilities, deviations from normal hot and cold weather conditions affect the Registrants' earnings and cash flows. Mild temperatures can result in decreased utilization of the Registrants' assets, lowering income and cash flows. At DTE Electric, ice storms, tornadoes, or high winds can damage the electric distribution system infrastructure and power generation facilities and require it to perform emergency repairs and incur material unplanned expenses. The expenses of storm restoration efforts may not be fully recoverable through the regulatory process. DTE Gas can experience higher than anticipated expenses from emergency repairs on its gas distribution infrastructure required as a result of weather related issues.
Unplanned power plant outages may be costly. Unforeseen maintenance may be required to safely produce electricity or comply with environmental regulations. As a result of unforeseen maintenance, the Registrants may be required to make spot market purchases of electricity that exceed the costs of generation. The Registrants' financial performance may be negatively affected if unable to recover such increased costs.
Regional, national, and international economic conditions can have an unfavorable impact on the Registrants. The Registrants' utility and DTE Energy's non-utility businesses follow the economic cycles of the customers they serve and credit risk of counterparties they do business with. Should the financial conditions of some of DTE Energy's significant customers deteriorate as a result of regional, national or international economic conditions, reduced volumes of electricity and gas, and demand for energy services DTE Energy supplies, collections of accounts receivable, reductions in federal and state energy assistance funding, and potentially higher levels of lost gas or stolen gas and electricity could result in decreased earnings and cash flows.
Renewable portfolio standards and energy waste reduction programs may affect the Registrants' business. The Registrants are subject to existing Michigan, and potential future, federal legislation and regulation requiring them to secure sources of renewable energy. The Registrants have complied with the existing federal and state legislation, but do not know what requirements may be added by federal or state legislation in the future. In addition, the Registrants expect to comply with new Michigan legislation increasing the percentage of power required to be provided by renewable energy sources. The Registrants cannot predict the financial impact or costs associated with complying with potential future legislation and regulations. Compliance with these requirements can significantly increase capital expenditures and operating expenses and can negatively affect the affordability of the rates charged to customers.
The Registrants are also required by Michigan legislation to implement energy waste reduction measures and provide energy waste reduction customer awareness and education programs. These requirements necessitate expenditures, and implementation of these programs creates the risk of reducing the Registrants' revenues as customers decrease their energy usage. The Registrants cannot predict how these programs will impact their business and future operating results.


Failure to attract and retain key executive officers and other skilled professional and technical employees could have an adverse effect on the Registrants operations. The Registrants' businesses are dependent on their ability to attract and retain skilled employees. Competition for skilled employees in some areas is high, and the inability to attract and retain these employees could adversely affect the Registrants' business and future operating results. In addition, the Registrants have an aging utility workforce, and the failure of a successful transfer of knowledge and expertise could negatively impact their operations.
A work interruption may adversely affect the Registrants. There are several bargaining units for DTE Energy's approximately 5,200 and DTE Electric's approximately 2,800 represented employees. The majority of represented employees are under contracts that expire in 2020 and 2021. A union choosing to strike would have an impact on the Registrants' businesses. The Registrants are unable to predict the effect a work stoppage would have on their costs of operations and financial performance.
DTE Energy's ability to utilize production tax credits may be limited. To reduce U.S. dependence on imported oil, the Internal Revenue Code provides production tax credits as an incentive for taxpayers to produce fuels and electricity from alternative sources. DTE Energy generated production tax credits from coke production, renewable gas recovery, reduced emission fuel, and gas production operations, and for the Registrants, renewable energy generation. If the Registrants' production tax credits were disallowed in whole or in part as a result of an IRS audit or changes in tax law, there could be additional tax liabilities owed for previously recognized tax credits that could significantly impact the Registrants' earnings and cash flows.
If DTE Energy's goodwill becomes impaired, it may be required to record a charge to earnings. DTE Energy annually reviews the carrying value of goodwill associated with acquisitions it has made for impairment. Factors that may be considered for purposes of this analysis include any change in circumstances indicating that the carrying value of DTE Energy goodwill may not be recoverable, such as a decline in stock price and market capitalization, future cash flows, and slower growth rates in the industry. DTE Energy cannot predict the timing, strength, or duration of any economic slowdown or subsequent recovery, worldwide or in the economy or markets in which it operates; however, when events or changes in circumstances indicate that the carrying value of these assets may not be recoverable, DTE Energy may take a non-cash impairment charge, which could potentially materially impact DTE Energy's results of operations and financial position.
The Registrants may not be fully covered by insurance. The Registrants have a comprehensive insurance program in place to provide coverage for various types of risks, including catastrophic damage as a result of severe weather or other natural disasters, war, terrorism, or a combination of other significant unforeseen events that could impact the Registrants' operations. Economic losses might not be covered in full by insurance, or the Registrants' insurers may be unable to meet contractual obligations.

Item 1B. Unresolved Staff Comments
None.



Item 3. Legal Proceedings
In March 2018, the Trenton Channel Power Plant experienced exceedances of its mercury emission limits. The exceedances were reported to the EPA and the MDEQ. On September 12, 2018, the EPA issued a NOV. DTE Electric is currently working with the EPA to address the NOV.  At this time, DTE Electric cannot predict the impact of the NOV.
For more information on legal proceedings and matters related to the Registrants, see Notes 9 and 18 to the Consolidated Financial Statements in Item 8 of this Report, "Regulatory Matters" and "Commitments and Contingencies," respectively.

Item 4. Mine Safety Disclosures
Not applicable.


Part II
Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters, and Issuer Purchases of Equity Securities
DTE Energy common stock is listed under the ticker symbol "DTE" on the New York Stock Exchange, which is the principal market for such stock.
At December 31, 2018, there were 181,925,281 shares of DTE Energy common stock outstanding. These shares were held by a total of 51,338 shareholders of record.
All of the 138,632,234 issued and outstanding shares of DTE Electric common stock, par value $10 per share, are owned by DTE Energy, and constitute 100% of the voting securities of DTE Electric. Therefore, no market exists for DTE Electric's common stock.
For information on DTE Energy dividend restrictions, see Note 16 to the Consolidated Financial Statements in Item 8 of this Report, "Short-Term Credit Arrangements and Borrowings."
All of DTE Energy's equity compensation plans that provide for the annual awarding of stock-based compensation have been approved by shareholders. For additional detail, see Note 21 to the Consolidated Financial Statements in Item 8 of this Report, "Stock-Based Compensation."
See the following table for information as of December 31, 2018:
 Number of Securities to be Issued Upon Exercise of Outstanding Options Weighted-Average Exercise Price of Outstanding Options Number of Securities Remaining Available for Future Issuance Under Equity Compensation Plans
Plans approved by shareholders52,100
 $43.30
 2,897,674
UNREGISTERED SALES OF DTE ENERGY EQUITY SECURITIES AND USE OF PROCEEDS
Purchases of DTE Energy Equity Securities by the Issuer and Affiliated Purchasers
The following table provides information about DTE Energy's purchases of equity securities that are registered by DTE Energy pursuant to Section 12 of the Exchange Act of 1934 for the quarter ended December 31, 2018:
 
Number of Shares Purchased(a)
 
Average Price
Paid per Share
(a)
 Number of Shares Purchased as Part of Publicly Announced
Plans or Programs
 Average Price Paid per Share Maximum Dollar
Value that May
Yet Be Purchased Under the Plans or Programs
10/01/2018 — 10/31/2018143
 $110.14
 
 
 
11/01/2018 — 11/30/2018
 $
 
 
 
12/01/2018 — 12/31/2018
 $
 
 
 
Total143
  
 
  
  

(a)Represents shares of DTE Energy common stock withheld to satisfy income tax obligations upon the vesting of restricted stock based on the price in effect at the grant date.


COMPARISON OF CUMULATIVE FIVE YEAR TOTAL RETURN
Total Return to DTE Energy Shareholders
(Includes reinvestment of dividends)
  Annual Return Percentage
Year Ended December 31,
Company/Index 2014 2015 2016 2017 2018
DTE Energy Company 34.61
 (3.77) 26.93
 14.59
 4.19
S&P 500 Index 13.69
 1.38
 11.95
 21.82
 (4.39)
S&P 500 Multi-Utilities Index 28.94
 (1.73) 18.56
 12.09
 1.77
  Indexed Returns
Year Ended December 31,
  Base Period          
Company/Index 2013 2014 2015 2016 2017 2018
DTE Energy Company 100.00
 134.61
 129.54
 164.41
 188.40
 196.30
S&P 500 Index 100.00
 113.69
 115.26
 129.04
 157.19
 150.29
S&P 500 Multi-Utilities Index 100.00
 128.94
 126.71
 150.22
 168.38
 171.35
dteenergy20_chart-06124a04.jpg



Item 6. Selected Financial Data
The following selected financial data of DTE Energy should be read in conjunction with the accompanying Management’s Discussion and Analysis in Item 7 of this Report and Combined Notes to Consolidated Financial Statements in Item 8 of this Report. This information has been omitted for DTE Electric per General Instruction I (2) (a) of Form 10-K for wholly-owned subsidiaries (reduced disclosure format).
 2018 2017 2016 2015 2014
 (In millions, except per share amounts)
Operating Revenues$14,212
 $12,607
 $10,630
 $10,337
 $12,301
Net Income Attributable to DTE Energy Company(a)
$1,120
 $1,134
 $868
 $727
 $905
Diluted Earnings Per Common Share$6.17
 $6.32
 $4.83
 $4.05
 $5.10
Financial Information         
Dividends declared per share of common stock$3.60
 $3.36
 $3.06
 $2.84
 $2.69
Total Assets$36,288
 $33,767
 $32,041
 $28,662
 $27,827
Long-Term Debt(b)
$12,134
 $12,185
 $11,269
 $8,760
 $8,271
Shareholders’ equity$10,237
 $9,512
 $9,011
 $8,772
 $8,327

(a)The 2017 results include a $105 million net income tax benefit related to the enactment of the TCJA.
(b)Long-Term Debt includes Capital lease obligations and excludes debt due within one year.

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations
The following combined discussion is separately filed by DTE Energy and DTE Electric. However, DTE Electric does not make any representations as to information related solely to DTE Energy or the subsidiaries of DTE Energy other than itself.
EXECUTIVE OVERVIEW
DTE Energy is a diversified energy company with 2018 Operating Revenues of approximately $14.2 billion and Total Assets of approximately $36.3 billion. DTE Energy is the parent company of DTE Electric and DTE Gas, regulated electric and natural gas utilities engaged primarily in the business of providing electricity and natural gas sales, distribution, and storage services throughout Michigan. DTE Energy operates three energy-related non-utility segments with operations throughout the United States.
The following table summarizes DTE Energy's financial results:
 Years Ended December 31,
 2018 2017 2016
 (In millions, except per share amounts)
Net Income Attributable to DTE Energy Company$1,120
 $1,134
 $868
Diluted Earnings per Common Share$6.17
 $6.32
 $4.83
The decrease in 2018 Net Income Attributable to DTE Energy Company was primarily due to lower earnings in the Gas Storage and Pipelines, Energy Trading, and Corporate and Other segments, partially offset by higher earnings in the Electric, Gas, and Power and Industrial Projects segments. The 2018 decrease was partially attributable to true-up adjustments for the remeasurement of deferred taxes of $21 million as the adjustments increased Income Tax Expense, of which $17 million was attributable to the regulated utilities and increased Regulatory liabilities. The increase in 2017 Net Income Attributable to DTE Energy Company was primarily due to higher earnings in the Gas Storage and Pipelines, Energy Trading, and Power and Industrial Projects segments, partially offset by lower earnings in the Corporate and Other segment. The 2017 increase was also due to $105 million of net income tax benefit related to the enactment of the TCJA.
Please see detailed explanations of segment performance in the following "Results of Operations" section.
DTE Energy's strategy is to achieve long-term earnings growth, a strong balance sheet, and an attractive dividend yield.


DTE Energy's utilities are investing capital to improve customer reliability through investments in base infrastructure and new generation, and to comply with environmental requirements. DTE Energy expects that planned significant capital investments will result in earnings growth. DTE Energy is focused on executing plans to achieve operational excellence and customer satisfaction with a focus on customer affordability. DTE Energy operates in a constructive regulatory environment and has solid relationships with its regulators.
In May 2017, DTE Energy announced its plan to reduce carbon emissions. This goal will be attained by cutting carbon emissions 30% by the early 2020s, 45% by 2030, 75% by 2040, and more than 80% by 2050. To achieve this reduction, DTE Energy will transition away from coal-powered sources and incorporate more renewable energy, energy waste reduction projects, demand response, and natural gas fueled generation. DTE Energy has already begun the transition in the way it produces power through the continued retirement of its aging coal-fired plants. In May 2018, DTE Energy announced its plans to accelerate its clean energy initiatives by targeting at least a 50% clean energy goal by 2030 to be achieved through a combination of investments in renewable energy and energy waste reduction projects. Refer to the "Capital Investments" section below for further discussion.
DTE Energy has significant investments in non-utility businesses. DTE Energy employs disciplined investment criteria when assessing growth opportunities that leverage its assets, skills, and expertise, and provides diversity in earnings and geography. Specifically, DTE Energy invests in targeted energy markets with attractive competitive dynamics where meaningful scale is in alignment with its risk profile. DTE Energy expects growth opportunities in the Gas Storage and Pipelines and Power and Industrial Projects segments.
A key priority for DTE Energy is to maintain a strong balance sheet which facilitates access to capital markets and reasonably priced short-term and long-term financing. Near-term growth will be funded through internally generated cash flows and the issuance of debt and equity. DTE Energy has an enterprise risk management program that, among other things, is designed to monitor and manage exposure to earnings and cash flow volatility related to commodity price changes, interest rates, and counterparty credit risk.
CAPITAL INVESTMENTS
DTE Energy's utility businesses require significant capital investments to maintain and improve the electric generation and electric and natural gas distribution infrastructure and to comply with environmental regulations and renewable energy requirements.
DTE Electric's capital investments over the 2019-2023 period are estimated at $11.3 billion comprised of $4.0 billion for capital replacements and other projects, $4.6 billion for distribution infrastructure, and $2.7 billion for new generation. DTE Electric has retired four coal-fired generation units at the Trenton Channel, River Rouge, and St Clair facilities and has announced plans to retire its remaining thirteen coal-fired generating units. Seven of these coal-fired generating units will be retired through 2023 at the Trenton Channel, River Rouge, and St. Clair facilities. The remaining coal-fired generating units at the Belle River and Monroe facilities are expected to be retired by 2040. The retired facilities will be replaced with renewables, energy waste reduction, demand response, and natural gas fueled generation. In April 2018, DTE Electric received approval from the MPSC to build a natural gas fueled combined cycle generation facility to provide approximately 1,100 megawatts of energy beginning in 2022. In August 2018, DTE Electric began construction on its natural gas fueled combined cycle generation facility. In March 2018, DTE Electric filed its 2018 Renewable Energy Plan with the MPSC proposing approximately 1,000 additional megawatts of energy from new wind and solar projects to be completed by 2022. The MPSC had previously approved 300 of the 1,000 additional megawatts for wind projects in an MPSC order received in September 2016. In January 2018, DTE Electric filed with the MPSC its five-year distribution operations investment and maintenance plan to improve system reliability. DTE Electric plans to seek regulatory approval for capital expenditures consistent with prior ratemaking treatment. For further discussion of regulatory matters, see Note 9 to the Consolidated Financial Statements, "Regulatory Matters."
DTE Gas' capital investments over the 2019-2023 period are estimated at $2.5 billion comprised of $1.2 billion for base infrastructure, and $1.3 billion for gas main renewal, meter move out, and pipeline integrity programs. DTE Gas plans to seek regulatory approval for capital expenditures consistent with ratemaking treatment.
DTE Energy's non-utility businesses' capital investments are primarily for expansion, growth, and ongoing maintenance. Gas Storage and Pipelines' capital investments over the 2019-2023 period are estimated at $4.0 billion to $5.0 billion for gathering and pipeline investments and expansions. Power and Industrial Projects' capital investments over the 2019-2023 period are estimated at $1.0 billion to $1.4 billion for industrial energy services and RNG projects.


ENVIRONMENTAL MATTERS
The Registrants are subject to extensive environmental regulation. Additional costs may result as the effects of various substances on the environment are studied and governmental regulations are developed and implemented. Actual costs to comply could vary substantially. The Registrants expect to continue recovering environmental costs related to utility operations through rates charged to customers, as authorized by the MPSC.
Air — DTE Electric is subject to the EPA ozone and fine particulate transport and acid rain regulations that limit power plant emissions of SO2 and NOX. The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to controls on fossil-fueled power plants to reduce SO2, NOX, mercury, and other emissions. Additional rulemakings may occur over the next few years which could require additional controls for SO2, NOX, and other hazardous air pollutants. To comply with existing requirements, DTE Electric spent approximately $2.4 billion through 2018. DTE Electric does not anticipate additional capital expenditures through 2025.
The EPA has implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, in 2015 the EPA finalized performance standards for emissions of carbon dioxide from new and existing EGUs. In February 2016, the U.S. Supreme Court granted petitioners' requests for a stay of the carbon rules for existing EGUs (also known as the EPA Clean Power Plan) pending final review by the courts. The Clean Power Plan has no legal effect while the stay is in place. On March 28, 2017, a presidential executive order was issued on "Promoting Energy Independence and Economic Growth." The order instructs the EPA to review, and if appropriate, suspend, revise or rescind the Clean Power Plan rule. Following the issuance of this order, the federal government requested the U.S. Court of Appeals for the D.C. Circuit to hold all legal challenges in abeyance until the review of these regulations is completed. On October 10, 2017, the EPA proposed to rescind the Clean Power Plan and announced its intent to issue an ANPR seeking input as to whether it should replace the rule and, if so, what form it should take. In August 2018, the EPA proposed revised emission guidelines for GHGs from existing electric utility generating units. The proposed rule, named the Affordable Clean Energy (ACE) rule, is intended to replace the Clean Power Plan rule. Comments on the proposed ACE rule were due on October 31, 2018. It is not possible to determine the potential impact of the EPA's proposed ACE rule on existing sources at this time.
Pending or future legislation or other regulatory actions could have a material impact on DTE Electric's operations and financial position and the rates charged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. DTE Electric would seek to recover these incremental costs through increased rates charged to its utility customers, as authorized by the MPSC.
Increased costs for energy produced from traditional coal-based sources due to recent, pending, and future regulatory initiatives, could also increase the economic viability of energy produced from renewable, natural gas fueled generation, and/or nuclear sources, energy waste reduction initiatives, and the potential development of market-based trading of carbon instruments which could provide new business opportunities for DTE Energy's utility and non-utility segments. At the present time, it is not possible to quantify the financial impacts of these climate related regulatory initiatives on the Registrants or their customers.
See Items 1. and 2. Business and Properties and Note 18 to the Consolidated Financial Statements in Item 8 of this Report, "Commitments and Contingencies," for further discussion of Environmental Matters.


OUTLOOK
The next few years will be a period of rapid change for DTE Energy and for the energy industry. DTE Energy's strong utility base, combined with its integrated non-utility operations, position it well for long-term growth.
Looking forward, DTE Energy will focus on several areas that are expected to improve future performance:
electric and gas customer satisfaction;
electric distribution system reliability;
new electric generation;
gas distribution system renewal;
rate competitiveness and affordability;
regulatory stability and investment recovery for the electric and gas utilities;
employee safety and engagement;
cost structure optimization across all business segments;
cash, capital, and liquidity to maintain or improve financial strength; and
investments that integrate assets and leverage skills and expertise.
DTE Energy will continue to pursue opportunities to grow its businesses in a disciplined manner if it can secure opportunities that meet its strategic, financial, and risk criteria.

RESULTS OF OPERATIONS
Management’s Discussion and Analysis of Financial Condition and Results of Operations includes financial information prepared in accordance with GAAP, as well as the non-GAAP financial measures, Utility Margin and Non-utility Margin, discussed below, which DTE Energy uses as measures of its operational performance. Generally, a non-GAAP financial measure is a numerical measure of financial performance, financial position or cash flows that excludes (or includes) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP.
DTE Energy uses Utility Margin and Non-utility Margin, non-GAAP financial measures, to assess its performance by reportable segment.
Utility Margin includes electric and gas Operating Revenues net of Fuel, purchased power, and gas expenses. The utilities’ fuel, purchased power, and natural gas supply are passed through to customers, and therefore, result in changes to the utilities’ revenues that are comparable to changes in such expenses. As such, DTE Energy believes Utility Margin provides a meaningful basis for evaluating the utilities’ operations across periods, as it excludes the revenue effect of fluctuations in these expenses.
The Non-utility Margin relates to the Power and Industrial Projects and Energy Trading segments. For the Power and Industrial Projects segment, Non-utility Margin primarily includes Operating Revenues net of Fuel, purchased power, and gas expenses. Operating Revenues include sales of refined coal to third parties and the affiliated Electric utility, metallurgical coke and related by-products, petroleum coke, renewable natural gas, and electricity, as well as rental income and revenues from utility-type consulting, management, and operational services. For the Energy Trading segment, Non-utility Margin includes revenue and realized and unrealized gains and losses from physical and financial power and gas marketing, optimization, and trading activities, net of Purchased power and gas related to these activities. DTE Energy evaluates its operating performance of these non-utility businesses using the measure of Operating Revenues net of Fuel, purchased power, and gas expenses.


Utility Margin and Non-utility Margin are not measures calculated in accordance with GAAP and should be viewed as a supplement to and not a substitute for the results of operations presented in accordance with GAAP. Utility Margin and Non-utility Margin do not intend to represent operating income, the most comparable GAAP measure, as an indicator of operating performance and are not necessarily comparable to similarly titled measures reported by other companies.
The following sections provide a detailed discussion of the operating performance and future outlook of DTE Energy's segments. Segment information, described below, includes intercompany revenues and expenses, and other income and deductions that are eliminated in the Consolidated Financial Statements.
 2018 2017 2016
 (In millions)
Net Income (Loss) Attributable to DTE Energy by Segment     
Electric$664
 $606
 $622
Gas150
 146
 138
Gas Storage and Pipelines235
 275
 119
Power and Industrial Projects161
 138
 95
Energy Trading39
 72
 (45)
Corporate and Other(129) (103) (61)
Net Income Attributable to DTE Energy Company$1,120
 $1,134
 $868
ELECTRIC
The Results of Operations discussion for DTE Electric is presented in a reduced disclosure format in accordance with General Instruction I (2) (a) of Form 10-K for wholly-owned subsidiaries.
The Electric segment consists principally of DTE Electric. Electric results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Utility operations$5,298
 $5,102
 $5,225
Fuel and purchased power — utility1,552
 1,454
 1,532
Utility Margin3,746
 3,648
 3,693
Operation and maintenance1,437
 1,382
 1,408
Depreciation and amortization836
 753
 750
Taxes other than income307
 302
 284
Asset (gains) losses and impairments, net(1) 
 
Operating Income1,167
 1,211
 1,251
Other (Income) and Deductions310
 284
 276
Income Tax Expense193
 321
 353
Net Income Attributable to DTE Energy Company$664
 $606
 $622
See DTE Electric's Consolidated Statements of Operations in Item 8 of this Report for a complete view of its results. For an explanation of differences between the Electric segment and DTE Electric's Consolidated Statements of Operations, refer to Note 20 to the Consolidated Financial Statements, "Retirement Benefits and Trusteed Assets."
Utility Margin increased $98 million in 2018 and decreased $45 million in 2017. Revenues associated with certain mechanisms and surcharges are offset by related expenses elsewhere in the Registrants' Consolidated Statements of Operations.


The following table details changes in various Utility Margin components relative to the comparable prior period:
 2018 2017
 (In millions)
Weather$152
 $(109)
Implementation of new rates51
 124
Regulatory mechanism — TRM40
 (26)
PSCR disallowance in 201713
 (13)
Base sales(3) (26)
TCJA rate reduction(156) 
Other regulatory mechanisms and other1
 5
Increase (decrease) in Utility Margin$98
 $(45)
 2018 2017 2016
 (In thousands of MWh)
DTE Electric Sales     
Residential15,959
 14,885
 15,875
Commercial17,282
 17,283
 17,521
Industrial10,324
 9,897
 10,004
Other221
 258
 264
 43,786
 42,323
 43,664
Interconnection sales(a)
2,796
 2,623
 2,334
Total DTE Electric Sales46,582
 44,946
 45,998
      
DTE Electric Deliveries     
Retail and wholesale43,786
 42,323
 43,664
Electric retail access, including self-generators(b)
4,737
 4,820
 4,936
Total DTE Electric Sales and Deliveries48,523
 47,143
 48,600

(a)Represents power that is not distributed by DTE Electric.
(b)Represents deliveries for self-generators that have purchased power from alternative energy suppliers to supplement their power requirements.
DTE Electric sales increased for residential, commercial, and industrial primarily due to favorable weather in 2018.
Operation and maintenance expense increased $55 million in 2018 and decreased $26 million in 2017. The increase in 2018 was primarily due to increased uncollectible expense of $34 million due to customer billing initiatives following implementation of the new billing system, increased power plant generation expense of $24 million, an increase in energy waste reduction expense of $10 million to meet higher energy savings targets, partially offset by decreased distribution operations expense of $13 million. The decrease in 2017 was primarily due to decreased power plant generation expenses of $66 million, partially offset by increased storm restoration expenses of $27 million, and increased line clearance expenses of $10 million. The decrease in power plant generation includes an increase of $6 million of costs related to the 2016 fire at a generation facility, offset by $21 million of insurance proceeds received in 2017.
Depreciation and amortization expense increased $83 million in 2018 and increased $3 million in 2017. In 2018, the increase was primarily due to an increase to depreciable base of $46 million and an increase of $42 million associated with the TRM, partially offset by a decrease in regulatory asset amortization of $5 million. In 2017, the increase was due to $45 million of increased expense from an increased depreciable base, partially offset by a decrease of $29 million associated with the TRM, and a decrease of $13 million in amortization of regulatory assets.


Other (Income) and Deductions increased $26 million in 2018 and increased $8 million in 2017. The increase in 2018 was primarily due to higher interest expense of $9 million and change in investment earnings (loss of $11 million in 2018 compared to a gain of $26 million in 2017), partially offset by decreased non-operating retirement benefits expense of $13 million and a contribution to the DTE Energy Foundation of $7 million in 2017. The increase in 2017 was primarily due to higher interest expense of $10 million, lower interest income of $8 million related to a sales and use tax settlement received in 2016, and a $7 million contribution to the DTE Energy Foundation, partially offset by $12 million of higher investment earnings and a $3 million decrease in Low Income Self-Sufficiency Plan (LSP) contributions to not-for-profit organizations in 2016.
Outlook DTE Electric will continue to move forward in its efforts to achieve operational excellence, sustain strong cash flows, and earn its authorized return on equity. DTE Electric expects that planned significant capital investments will result in earnings growth. DTE Electric will maintain a strong focus on customers by increasing reliability and satisfaction while keeping customer rate increases affordable. Looking forward, additional factors may impact earnings such as weather, the outcome of regulatory proceedings, benefit plan design changes, investment returns and changes in discount rate assumptions in benefit plans and health care costs, uncertainty of legislative or regulatory actions regarding climate change, and effects of energy waste reduction programs.
DTE Electric filed a rate case with the MPSC on July 6, 2018 requesting an increase in base rates of $328 million based on a projected twelve-month period ending April 30, 2020. The requested increase in base rates is primarily due to an increase in net plant resulting from infrastructure investments, depreciation expense, as requested in the 2016 DTE Electric Depreciation Case Filing, and reliability improvement projects. The rate filing also requests an increase in return on equity from 10.0% to 10.5% and includes projected changes in sales, operation and maintenance expenses, and working capital. In addition, the rate filing requests an Infrastructure Recovery Mechanism to recover the incremental revenue requirement associated with certain distribution, fossil generation, and nuclear generation capital expenditures through 2022. DTE Electric also included Calculation C in this filing to address all remaining issues relative to the enactment of the TCJA, which is primarily the remeasurement of deferred taxes and how the amounts deferred as Regulatory liabilities will flow to ratepayers. A final MPSC order in this case is expected by May 2019. Refer to Note 9 to the Consolidated Financial Statements, “Regulatory Matters” for additional information.
GAS
The Gas segment consists principally of DTE Gas. Gas results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Utility operations$1,436
 $1,388
 $1,324
Cost of gas — utility446
 443
 454
Utility Margin990
 945
 870
Operation and maintenance502
 449
 440
Depreciation and amortization133
 123
 106
Taxes other than income73
 65
 64
Asset (gains) losses and impairments, net
 
 4
Operating Income282
 308
 256
Other (Income) and Deductions65
 84
 41
Income Tax Expense67
 78
 77
Net Income Attributable to DTE Energy Company$150
 $146
 $138
Utility Margin increased $45 million in 2018 and increased $75 million in 2017. Revenues associated with certain surcharges are offset by related expenses elsewhere in DTE Energy's Consolidated Statements of Operations.


The following table details changes in various Utility Margin components relative to the comparable prior period:
 2018 2017
 (In millions)
Weather$46
 $(6)
Implementation of new rates15
 80
Midstream storage and transportation revenues15
 (5)
Regulatory mechanism — RDM(3) 4
TCJA rate reduction(40) 
Other regulatory mechanisms and other12
 2
Increase in Utility Margin$45
 $75
 2018 2017 2016
 (In Bcf)
Gas Markets     
Gas sales135
 119
 116
End-user transportation187
 165
 182
 322
 284
 298
Intermediate transportation329
 260
 214
Total Gas sales651
 544
 512
Operation and maintenance expense increased $53 million in 2018 and increased $9 million in 2017. The increase in 2018 was primarily due to increased uncollectible expense of $28 million due to customer billing initiatives following implementation of a new customer billing system and higher gas operations expenses of $22 million, which included increased investment spending and higher pipeline integrity expenses. The increase in 2017 was primarily due to increased corporate expenses of $3 million and increased gas operations expenses of $3 million.
Depreciation and amortization expense increased $10 million in 2018 and increased $17 million in 2017. The increase in 2018 was primarily due to an increased depreciable base. The increase in 2017 was primarily due to an increased depreciable base and higher depreciation rates.
Other (Income) and Deductions decreased $19 million in 2018 and increased $43 million in 2017. The decrease in 2018 was primarily due to lower contributions to the DTE Energy Foundation and other not-for-profit organizations of $27 million, partially offset by higher net interest expense of $6 million. The increase in 2017 was primarily due to increased non-operating retirement benefits expenses of $31 million, increased contributions to the DTE Energy Foundation and other not-for-profit organizations of $7 million and higher interest expense of $5 million.
Outlook — DTE Gas will continue to move forward in its efforts to achieve operational excellence, sustain strong cash flows, and earn its authorized return on equity. DTE Gas expects that planned significant infrastructure capital investments will result in earnings growth. Looking forward, additional factors may impact earnings such as weather, the outcome of regulatory proceedings, benefit plan design changes, and investment returns and changes in discount rate assumptions in benefit plans and health care costs. DTE Gas expects to continue its efforts to improve productivity and decrease costs while improving customer satisfaction with consideration of customer rate affordability.
DTE filed its Calculation C case with the MPSC on November 16, 2018 to reduce the revenue requirement by $12 million related to the amortization of deferred tax remeasurement. Calculation C addresses all remaining issues relative to the enactment of the TCJA, which is primarily the remeasurement of deferred taxes and how the amounts deferred as Regulatory liabilities will flow to ratepayers. Refer to Note 9 to the Consolidated Financial Statements, “Regulatory Matters” for additional information.


GAS STORAGE AND PIPELINES
The Gas Storage and Pipelines segment consists of the non-utility gas pipelines and storage businesses. Gas Storage and Pipelines results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Non-utility operations$485
 $453
 $302
Cost of gas — Non-utility22
 30
 6
Operation and maintenance103
 83
 81
Depreciation and amortization82
 76
 45
Taxes other than income8
 8
 4
Asset (gains) losses and impairments, net
 2
 
Operating Income270
 254
 166
Other (Income) and Deductions(61) (18) (31)
Income Tax Expense (Benefit)68
 (30) 71
Net Income263
 302
 126
Less: Net Income Attributable to Noncontrolling Interests28
 27
 7
Net Income Attributable to DTE Energy Company$235
 $275
 $119
Operating Revenues — Non-utility operations increased $32 million in 2018 and increased $151 million in 2017. The increase in both periods was primarily due to increased pipeline and gathering volumes. The 2017 increase was also due to the acquisition of AGS and SGG in October 2016.
Cost of gas — Non-utility decreased $8 million in 2018 and increased $24 million in 2017. The 2018 decrease was driven by lower physical purchases of gas from AGS customers for resale to optimize available transportation capacity. The 2017 increase was driven by higher physical purchases of gas from AGS customers for resale to optimize available transportation capacity.
Operation and maintenance expense increased $20 million in 2018 and increased $2 million in 2017. The 2018 increase was primarily due to increased labor related expenses and additional compression activity on the Bluestone Pipeline and Susquehanna gathering systems.
Depreciation and amortization expense increased $6 million in 2018 and increased $31 million in 2017. The 2017 increase was primarily due to the acquisition of AGS and SGG in October 2016.
Other (Income) and Deductions increased $43 million in 2018 and decreased $13 million in 2017. The 2018 increase was primarily due to increased earnings from pipeline investments and a $16 million net loss on extinguishment of debt within the storage business in 2017, partially offset by higher interest expense. The 2017 decrease was primarily due to a $16 million net loss on extinguishment of debt within the storage business and contributions to the DTE Energy Foundation and other not-for-profit organizations, partially offset by increased earnings from pipeline investments.
Income Tax Expense (Benefit) increased $98 million in 2018 and decreased $101 million in 2017. The changes were primarily driven by the $115 million remeasurement of deferred tax assets and liabilities to reflect the reduction in the corporate tax rate from the enactment of the TCJA in December 2017. The 2017 change was partially offset by increased tax expense on higher earnings in 2017.
Net Income Attributable to Noncontrolling Interests increased $1 million in 2018 and increased $20 million in 2017. The 2017 increase was primarily due to the acquisition of SGG in October 2016.
Outlook — DTE Energy believes its long-term agreements with producers and the quality of the natural gas reserves in the Marcellus/Utica region soundly position the gathering systems for future revenues.
NEXUS Pipeline was placed in service in in October 2018. The NEXUS Pipeline provides a transportation path for Appalachian Basin shale gas, including Utica and Marcellus shale gas, directly to consuming markets in northern Ohio, southeastern Michigan, and Dawn Ontario. DTE Energy owns a 50% partnership interest in the NEXUS Pipeline with an investment balance of $1.26 billion at December 31, 2018.


On January 11, 2019, NEXUS signed an agreement to purchase Generation Pipeline, LLC, a public utility regulated by the Public Utilities Commission of Ohio. This 23-mile pipeline system supplies gas to industrial customers in the Toledo, OH area, has existing interconnects with ANR Pipeline Company and Panhandle Eastern Pipeline Company, and is located 4 miles away from Nexus. The transaction is expected to close in the first half of 2019 upon regulatory approvals.
AGS and SGG provide a platform for midstream growth and access to further investment opportunities in the Appalachian basin, an additional connection to the NEXUS Pipeline which should drive incremental volumes on the NEXUS Pipeline, and producer relationships that may lead to more partnering opportunities.
Gas Storage and Pipelines expects to maintain its steady growth by developing an asset portfolio with multiple growth platforms through investment in new projects and expansions. Gas Storage and Pipelines will continue to look for additional investment opportunities and other storage and pipeline projects at favorable prices.
POWER AND INDUSTRIAL PROJECTS
The Power and Industrial Projects segment is comprised primarily of projects that deliver energy and utility-type products and services to industrial, commercial, and institutional customers, produce reduced emissions fuel, and sell electricity and pipeline-quality gas from renewable energy projects. Power and Industrial Projects results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Non-utility operations$2,204
 $2,089
 $1,906
Fuel, purchased power, and gas — non-utility1,888
 1,813
 1,640
Non-utility Margin316
 276
 266
Operation and maintenance363
 342
 317
Depreciation and amortization67
 72
 72
Taxes other than income12
 11
 13
Asset (gains) losses and impairments, net27
 20
 (1)
Operating Loss(153) (169) (135)
Other (Income) and Deductions(89) (63) (49)
Income Taxes     
Benefit(7) (42) (26)
Production Tax Credits(188) (153) (114)
 (195) (195) (140)
Net Income131
 89
 54
Less: Net Loss Attributable to Noncontrolling Interests(30) (49) (41)
Net Income Attributable to DTE Energy Company$161
 $138
 $95


Operating Revenues — Non-utility operations increased $115 million in 2018 and increased $183 million in 2017. The changes are due to the following:
 2018
 (In millions)
Higher demand due to improved conditions in the steel business$59
Higher production in the renewables business25
Higher production, offset by lower coal prices in the REF business18
Higher sales primarily associated with new contracts in the on-site business13
 $115
  
 2017
 (In millions)
Higher demand due to improved conditions in the steel business$107
Higher production driven by new projects, offset by lower coal prices in the REF business102
Lower production and one-time recovery in 2016, offset by an acquisition in the renewables business(9)
Lower sales primarily associated with expired contracts in the on-site business(17)
 $183
Non-utility Margin increased $40 million in 2018 and increased $10 million in 2017. The changes are due to the following:
 2018
 (In millions)
Higher production in the renewables business$20
Higher sales primarily associated with new contracts in the on-site business12
Higher demand due to improved conditions in the steel business8
 $40
  
 2017
 (In millions)
Higher demand due to improved conditions in the steel business$42
Lower production and one-time recovery in 2016 in the renewables business(11)
Lower sales primarily associated with expired contracts in the on-site business(15)
Other(6)
 $10
Operation and maintenance expense increased $21 million in 2018 and increased $25 million in 2017. The 2018 increase was primarily due to higher production in the REF business of $11 million and new contracts in the on-site business of $8 million. The 2017 increase was primarily due to an increase in maintenance spending driven by improved conditions in the steel business of $16 million, higher maintenance and a new acquisition in the renewables business of $7 million, and an increase associated with new projects in the REF business of $5 million, offset by lower spending as a result of Shenango plant closure activities in the first half of 2016 of $6 million.
Asset (gains) losses and impairments, net increased $7 million in 2018 from the net loss of $20 million in 2017 and decreased $21 million in 2017 from the net gain of $1 million in 2016. The 2018 increase was primarily due to $15 million of a liability adjustment related to contingent consideration and an $8 million asset write-off associated with the renewable business in anticipation of a contract ending in 2020. The 2017 decrease was primarily due to an impairment in the REF business of $14 million and an impairment of a petroleum coke project of $6 million.


Other (Income) and Deductions increased $26 million in 2018 and increased $14 million in 2017. The 2018 increase was primarily due to higher production in the REF business of $20 million and decreased contributions to the DTE Energy Foundation of $4 million. The 2017 increase was primarily due to increased equity earnings in the renewable business of $9 million and insurance settlements in the renewable and REF businesses of $6 million, offset by increased contributions to the DTE Energy Foundation of $6 million.
Income Taxes — Benefit decreased by $35 million in 2018 and increased by $16 million in 2017. The 2018 decrease was primarily due to the 2017 remeasurement of deferred tax assets and liabilities to reflect the reduction in the corporate tax rate from the enactment of the TCJA in December 2017. The increase in 2017 was primarily due to the remeasurement of deferred tax assets and liabilities to reflect the reduction in the corporate tax rate from the enactment of the TCJA in December 2017 of $21 million, an increase due to higher pretax loss of $7 million, and a decrease due to a worthless stock deduction associated with the Shenango closure in 2016 of $10 million.
Income Taxes — Production Tax Credits increased by $35 million in 2018 and increased $39 million in 2017. The increase in both periods was primarily due to higher production in the REF business.
Net Loss Attributable to Noncontrolling Interests decreased by $19 million in 2018 and increased by $8 million in 2017. The 2018 decrease was primarily due to termination of a project in the REF business. The 2017 increase was primarily due to a change in the ownership percentage in one of the REF projects of $8 million.
Outlook — Power and Industrial Projects has constructed and placed in service REF facilities at ten sites including facilities located at seven third-party owned coal-fired power plants. DTE Energy has sold membership interests in five of the facilities and entered into lease arrangements in three of the facilities. Three REF facilities will phase out in 2019 with the remaining seven to be phased out at the end of 2021.
Power and Industrial Projects will continue to leverage its extensive energy-related operating experience and project management capability to develop additional energy projects to serve energy intensive industrial customers.
ENERGY TRADING
Energy Trading focuses on physical and financial power and natural gas marketing and trading, structured transactions, enhancement of returns from its asset portfolio, and optimization of contracted natural gas pipeline transportation and storage positions. Energy Trading also provides natural gas, power, and related services, which may include the management of associated storage and transportation contracts on the customers' behalf, and the supply or purchase of renewable energy credits to various customers. Energy Trading results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Non-utility operations$5,557
 $4,277
 $2,575
Purchased power and gas — non-utility5,417
 4,077
 2,552
Non-utility Margin140
 200
 23
Operation and maintenance75
 68
 63
Depreciation and amortization5
 5
 3
Taxes other than income5
 4
 2
Operating Income (Loss)55
 123
 (45)
Other (Income) and Deductions3
 2
 29
Income Tax Expense (Benefit)13
 49
 (29)
Net Income (Loss) Attributable to DTE Energy Company$39
 $72
 $(45)
Operating Revenues — Non-utility operations and Purchased power and gas — non-utility were impacted primarily by an increase in volumes as well as an increase in gas prices for the years ended December 31, 2018 and December 31, 2017, primarily in the gas structured strategy.


Non-utility Margin decreased $60 million in 2018 and increased $177 million in 2017. The change in both periods was primarily due to timing from the unrealized and realized margins presented in the following tables:
 2018
 (In millions)
Unrealized Margins(a)
 
Favorable results, primarily in the power trading strategy$20
Unfavorable results, primarily in gas structured, and power full requirements strategies(b)
(100)
 (80)
Realized Margins(a)
 
Favorable results, primarily in the gas structured strategy54
Unfavorable results, primarily in the power full requirements strategy(c)
(34)
 20
Decrease in Non-utility Margin$(60)

(a)Natural gas structured transactions typically involve a physical purchase or sale of natural gas in the future and/or natural gas basis financial instruments which are derivatives and a related non-derivative pipeline transportation contract. These gas structured transactions can result in significant earnings volatility as the derivative components are marked-to-market without revaluing the related non-derivative contracts.
(b)Amount includes $74 million of timing related losses related to gas strategies which will reverse in future periods as the underlying contracts settle.
(c)Amount includes $11 million of timing related gains related to gas strategies recognized in previous periods that reversed as the underlying contracts settled.
 2017
 (In millions)
Unrealized Margins(a)
 
Favorable results, primarily in gas structured and gas full requirements strategies(b)
$113
Unfavorable results, primarily in power and gas trading and power full requirements strategies(26)
 87
Realized Margins(a)
 
Favorable results, primarily in gas structured, environmental trading and gas storage strategies(c)
103
Unfavorable results, primarily in the power full requirements strategy(13)
 90
Increase in Non-utility Margin$177

(a)Natural gas structured transactions typically involve a physical purchase or sale of natural gas in the future and/or natural gas basis financial instruments which are derivatives and a related non-derivative pipeline transportation contract. These gas structured transactions can result in significant earnings volatility as the derivative components are marked-to-market without revaluing the related non-derivative contracts.
(b)Amount includes $113 million of timing related gains related to gas strategies which will reverse in future periods as the underlying contracts settle.
(c)Amount includes $95 million of timing related losses related to gas strategies recognized in previous periods that reversed as the underlying contracts settled.
Other (Income) and Deductions increased$1 million in 2018 and decreased $27 million in 2017 due to contributions to the DTE Energy Foundation in 2016.
Outlook — In the near-term, Energy Trading expects market conditions to remain challenging, and the profitability of this segment may be impacted by the volatility in commodity prices and the uncertainty of impacts associated with regulatory changes, and changes in operating rules of RTOs. Significant portions of the Energy Trading portfolio are economically hedged. Most financial instruments and physical power and natural gas contracts are deemed derivatives, whereas natural gas inventory, pipeline transportation, renewable energy credits, and storage assets are not derivatives. As a result, Energy Trading will experience earnings volatility as derivatives are marked-to-market without revaluing the underlying non-derivative contracts and assets. Energy Trading's strategy is to economically manage the price risk of these underlying non-derivative contracts and assets with futures, forwards, swaps, and options. This results in gains and losses that are recognized in different interim and annual accounting periods.
See also the "Fair Value" section herein and Notes 12 and 13 to the Consolidated Financial Statements in Item 8 of this Report, "Fair Value" and "Financial and Other Derivative Instruments," respectively.


CORPORATEEMPLOYEES
DTE Energy and its subsidiaries had approximately 10,600 employees as of December 31, 2018, of which approximately 5,200 were represented by unions. DTE Electric had approximately 4,900 employees as of December 31, 2018, of which approximately 2,800 were represented by unions. There are several bargaining units for DTE Energy subsidiaries' represented employees. The majority of represented employees for both DTE Energy and DTE Electric are under contracts that expire in 2020 and 2021.

Item 1A. Risk Factors
There are various risks associated with the operations of the Registrants' utility businesses and DTE Energy's non-utility businesses. To provide a framework to understand the operating environment of the Registrants, below is a brief explanation of the more significant risks associated with their businesses. Although the Registrants have tried to identify and discuss key risk factors, others could emerge in the future. Each of the following risks could affect performance.
The Registrants are subject to rate regulation. Electric and gas rates for the utilities are set by the MPSC and the FERC and cannot be changed without regulatory authorization. The Registrants may be negatively impacted by new regulations or interpretations by the MPSC, the FERC, or other regulatory bodies. The Registrants' ability to recover costs may be impacted by the time lag between the incurrence of costs and the recovery of the costs in customers' rates. Regulators also may decide to disallow recovery of certain costs in customers' rates if they determine that those costs do not meet the standards for recovery under current governing laws and regulations. Regulators may also disagree with the Registrants' rate calculations under the various mechanisms that are intended to mitigate the risk to their utilities related to certain aspects of the business. If the Registrants cannot agree with regulators on an appropriate reconciliation of those mechanisms, it may impact the Registrants' ability to recover certain costs through customer rates. Regulators may also decide to eliminate these mechanisms in future rate cases, which may make it more difficult for the Registrants to recover their costs in the rates charged to customers. The Registrants cannot predict what rates the MPSC will authorize in future rate cases. New legislation, regulations, or interpretations could change how the business operates, impact the Registrants' ability to recover costs through rates or the timing of such recovery, or require the Registrants to incur additional expenses.
Changes to Michigan's electric retail access program could negatively impact the Registrants' financial performance. The State of Michigan currently experiences a hybrid market, where the MPSC continues to regulate electric rates for DTE Electric customers, while alternative electric suppliers charge market-based rates. MPSC rate orders, and energy legislation enacted by the State of Michigan, have placed a 10% cap on the total potential retail access migration. However, even with the legislated 10% cap on participation, there continues to be legislative and financial risk associated with the electric retail access program. Electric retail access migration is sensitive to market price and full service electric price changes. The Registrants are required under current regulation to provide full service to retail access customers that choose to return, potentially resulting in the need for additional generating capacity.


The Registrants' electric distribution system and DTE Energy's gas distribution system are subject to risks from their operation, which could reduce revenues, increase expenses, and have a material adverse effect on their business, financial position, and results of operations. The Registrants' electric distribution and DTE Energy’s gas distribution systems are subject to many operational risks. These operational systems and infrastructure have been in service for many years. Equipment, even when maintained in accordance with good utility practices, is subject to operational failure, including events that are beyond the Registrants' control, and could require significant operation and maintenance expense or capital expenditures to operate efficiently. Because the Registrants’ distribution systems are interconnected with those of third parties, the operation of the Registrants’ systems could be adversely affected by unexpected or uncontrollable events occurring on the systems of such third parties.
DTE Energy's non-utility businesses may not perform to its expectations. DTE Energy relies on non-utility operations for an increasing portion of earnings. If DTE Energy's current and contemplated non-utility investments do not perform at expected levels, DTE Energy could experience diminished earnings and a corresponding decline in shareholder value.
DTE Energy relies on cash flows from subsidiaries. DTE Energy is a holding company. Cash flows from the utility and non-utility subsidiaries are required to pay interest expenses and dividends on DTE Energy debt and securities. Should a major subsidiary not be able to pay dividends or transfer cash flows to DTE Energy, its ability to pay interest and dividends would be restricted.
The Registrants' businesses have safety risks. The Registrants' electric distribution system, power plants, renewable energy equipment, and other facilities, and DTE Energy's gas distribution system, gas infrastructure, and other facilities, could be involved in incidents that result in injury, death, or property loss to employees, customers, third parties, or the public. Although the Registrants have insurance coverage for many potential incidents, depending upon the nature and severity of any incident, they could experience financial loss, damage to their reputation, and negative consequences from regulatory agencies or other public authorities.
Environmental laws and liability may be costly. The Registrants are subject to, and affected by, numerous environmental regulations. These regulations govern air emissions, water quality, wastewater discharge, and disposal of solid and hazardous waste. Compliance with these regulations can significantly increase capital spending, operating expenses, and plant down times, and can negatively affect the affordability of the rates charged to customers.
Uncertainty around future environmental regulations creates difficulty planning long-term capital projects in the Registrants' generation fleet and, for DTE Energy's gas distribution businesses. These laws and regulations require the Registrants to seek a variety of environmental licenses, permits, inspections, and other regulatory approvals. The Registrants could be required to install expensive pollution control measures or limit or cease activities, including the retirement of certain generating plants, based on these regulations. Additionally, the Registrants may become a responsible party for environmental cleanup at sites identified by a regulatory body. The Registrants cannot predict with certainty the amount and timing of future expenditures related to environmental matters because of the difficulty of estimating cleanup costs. There is also uncertainty in quantifying liabilities under environmental laws that impose joint and several liability on potentially responsible parties.
The Registrants may also incur liabilities as a result of potential future requirements to address climate change issues. Proposals for voluntary initiatives and mandatory controls are being discussed both in the United States and worldwide to reduce GHGs such as carbon dioxide, a by-product of burning fossil fuels. If increased regulations of GHG emissions are implemented, the operations of DTE Electric's fossil-fueled generation assets may be significantly impacted. Since there can be no assurances that environmental costs may be recovered through the regulatory process, the Registrants' financial performance may be negatively impacted as a result of environmental matters.
For DTE Energy, future environmental regulation of natural gas extraction techniques, including hydraulic fracturing, being discussed both at the United States federal level and by some states may affect the profitability of natural gas extraction businesses which could affect demand for, and profitability of, DTE Energy's gas transportation businesses.
Threats of cyber incidents, physical security, and terrorism could affect the Registrants' business. Issues may threaten the Registrants such as cyber incidents, physical security, or terrorism that may disrupt the Registrants' operations, and could harm the Registrants' operating results.


Information security risks have increased in recent years as a result of the proliferation of new technologies and the increased sophistication and frequency of cyberattacks, and data security breaches. The Registrants' industry requires the continued operation of sophisticated information and control technology systems and network infrastructure. Despite implementation of security measures, all of the Registrants' technology systems are vulnerable to disability or failures due to cyber incidents, physical security threats, acts of war or terrorism, and other causes, as well as loss of operational control of the Registrants' electric generation and distribution assets and, DTE Energy's gas distribution assets. If the Registrants' information technology systems were to fail and they were unable to recover in a timely way, the Registrants may be unable to fulfill critical business functions, which could have a material adverse effect on the Registrants' business, operating results, and financial condition.
Suppliers, vendors, contractors, and information technology providers have access to systems that support the Registrants’ operations and maintain customer and employee data.  A breach of these third-party systems could adversely affect the business as if it was a breach of our own system.  Also, because the Registrants’ generation and distribution systems are part of an interconnected system, a disruption caused by a cyber incident at another utility, electric generator, system operator, or commodity supplier could also adversely affect the Registrants’ businesses, operating results, and financial condition.
In addition, the Registrants' generation plants and electrical distribution facilities, and DTE Energy's gas pipeline and storage facilities, in particular, may be targets of physical security threats or terrorist activities that could disrupt the Registrants' ability to produce or distribute some portion of their products. The Registrants have increased security as a result of past events and may be required by regulators or by the future threat environment to make investments in security that the Registrants cannot currently predict.
Failure to maintain the security of personally identifiable information could adversely affect the Registrants. In connection with the Registrants' businesses, they collect and retain personally identifiable information of their customers, shareholders, and employees. Customers, shareholders, and employees expect that the Registrants will adequately protect their personal information. The regulatory environment surrounding information security and privacy is increasingly demanding. A significant theft, loss, or fraudulent use of customer, shareholder, employee, or Registrant data by cybercrime or otherwise, could adversely impact the Registrants' reputation, and could result in significant costs, fines, and litigation.
Construction and capital improvements to the Registrants' power facilities, DTE Energy's distribution systems and its Gas Storage and Pipelines business subject them to risk. The Registrants are managing ongoing, and planning future, significant construction and capital improvement projects at the Registrants' multiple power generation and distribution facilities, at DTE Energy's gas distribution system, and at DTE Energy's Gas Storage and Pipelines business. Many factors that could cause delays or increased prices for these complex projects are beyond the Registrants' control, including the cost of materials and labor, subcontractor performance, timing and issuance of necessary permits or approvals (including required certificates from regulatory agencies), construction disputes, impediments to acquiring rights-of-way or land rights on a timely basis and on acceptable terms, cost overruns, and weather conditions. Failure to complete these projects on schedule and on budget for any reason could adversely affect the Registrants' financial performance, operations, or expected investment returns at the affected facilities, businesses and development projects.
Operation of a nuclear facility subjects the Registrants to risk. Ownership of an operating nuclear generating plant subjects the Registrants to significant additional risks. These risks include, among others, plant security, environmental regulation and remediation, changes in federal nuclear regulation, increased capital expenditures to meet industry requirements, and operational factors that can significantly impact the performance and cost of operating a nuclear facility compared to other generation options. Insurance maintained by the Registrants for various nuclear-related risks may not be sufficient to cover the Registrants' costs in the event of an accident or business interruption at the nuclear generating plant, which may affect the Registrants' financial performance. In addition, the Registrants' nuclear decommissioning trust fund, to finance the decommissioning of the nuclear generating plant, may not be sufficient to fund the cost of decommissioning. A decline in market value of assets held in decommissioning trust funds due to poor investment performance or other factors may increase the funding requirements for these obligations. Any increase in funding requirements may have a material impact on the Registrants’ liquidity, financial position, or results of operations.


The supply and/or price of energy commodities and/or related services may impact the Registrants' financial results. The Registrants are dependent on coal for much of their electrical generating capacity as well as uranium for their nuclear operations. DTE Energy's access to natural gas supplies is critical to ensure reliability of service for utility gas customers. DTE Energy's non-utility businesses are also dependent upon supplies and prices of energy commodities and services. Price fluctuations, fuel supply disruptions, and changes in transportation costs, could have a negative impact on the amounts DTE Electric charges utility customers for electricity and DTE Gas charges utility customers for gas, and on the profitability of DTE Energy's non-utility businesses. The Registrants' hedging strategies and regulatory recovery mechanisms may be insufficient to mitigate the negative fluctuations in commodity supply prices in their utility and, for DTE Energy, non-utility businesses, and the Registrants' financial performance may therefore be negatively impacted by price fluctuations. The price of energy also impacts the market for DTE Energy's non-utility businesses that compete with utilities and alternative electric suppliers.
The supply and/or price of other industrial raw and finished inputs and/or related services may impact the Registrants' financial results. The Registrants are dependent on supplies of certain commodities, such as copper and limestone, among others, and industrial materials, and services in order to maintain day-to-day operations and maintenance of their facilities. Price fluctuations, or supply interruptions for these commodities and other items, could have a negative impact on the amounts charged to customers for the Registrants' utility products and, for DTE Energy, on the profitability of the non-utility businesses.
Emerging technologies may have a material adverse effect on the Registrants. Advances in technology that produce power or reduce power consumption include cost-effective renewable energy technologies, distributed generation, energy waste reduction technologies, and energy storage devices. Such developments may impact the price of energy, may affect energy deliveries as customer-owned generation becomes more cost-effective, may require further improvements to our distribution systems to address changing load demands, and could make portions of our electric system power supply and/or distribution facilities obsolete prior to the end of their useful lives. Such technologies could also result in further declines in commodity prices or demand for delivered energy. Each of these factors could materially affect the Registrants’ results of operations, cash flows, or financial position.
Adverse changes in the Registrants' credit ratings may negatively affect them. Regional and national economic conditions, increased scrutiny of the energy industry and regulatory changes, as well as changes in the Registrants' economic performance, could result in credit agencies reexamining their credit ratings. While credit ratings reflect the opinions of the credit agencies issuing such ratings and may not necessarily reflect actual performance, a downgrade in the Registrants' credit ratings below investment grade could restrict or discontinue their ability to access capital markets and could result in an increase in their borrowing costs, a reduced level of capital expenditures, and could impact future earnings and cash flows. In addition, a reduction in the Registrants' credit ratings may require them to post collateral related to various physical or financially settled contracts for the purchase of energy-related commodities, products, and services, which could impact their liquidity.
Poor investment performance of pension and other postretirement benefit plan assets and other factors impacting benefit plan costs could unfavorably impact the Registrants' liquidity and results of operations. The Registrants' costs of providing non-contributory defined benefit pension plans and other postretirement benefit plans are dependent upon a number of factors, such as the rates of return on plan assets, the level of interest rates used to measure the required minimum funding levels of the plans, future government regulation, and the Registrants' required or voluntary contributions made to the plans. The performance of the debt and equity markets affects the value of assets that are held in trust to satisfy future obligations under the Registrants' plans. The Registrants have significant benefit obligations and hold significant assets in trust to satisfy these obligations. These assets are subject to market fluctuations and will yield uncertain returns, which may fall below the Registrants' projected return rates. A decline in the market value of the pension and other postretirement benefit plan assets will increase the funding requirements under the pension and other postretirement benefit plans if the actual asset returns do not recover these declines in the foreseeable future. Additionally, the pension and other postretirement benefit plan liabilities are sensitive to changes in interest rates. If interest rates decrease, the liabilities increase, resulting in increasing benefit expense and funding requirements. Also, if future increases in pension and other postretirement benefit costs as a result of reduced plan assets are not recoverable from the Registrants' utility customers, the results of operations and financial position of the Registrants could be negatively affected. Without sustained growth in the plan investments over time to increase the value of plan assets, the Registrants could be required to fund these plans with significant amounts of cash. Such cash funding obligations could have a material impact on the Registrants' cash flows, financial position, or results of operations.


The Registrants' ability to access capital markets is important. The Registrants' ability to access capital markets is important to operate their businesses and to fund capital investments. Turmoil in credit markets may constrain the Registrants' ability, as well as the ability of their subsidiaries, to issue new debt, including commercial paper, and refinance existing debt at reasonable interest rates. In addition, the level of borrowing by other energy companies, and the market as a whole, could limit the Registrants' access to capital markets. The Registrants' long-term revolving credit facilities do not expire until 2022, but the Registrants regularly access capital markets to refinance existing debt or fund new projects at the Registrants' utilities and DTE Energy's non-utility businesses, and the Registrants cannot predict the pricing or demand for those future transactions.
DTE Energy's participation in energy trading markets subjects it to risk. Events in the energy trading industry have increased the level of scrutiny on the energy trading business and the energy industry as a whole. In certain situations, DTE Energy may be required to post collateral to support trading operations, which could be substantial. If access to liquidity to support trading activities is curtailed, DTE Energy could experience decreased earnings potential and cash flows. Energy trading activities take place in volatile markets and expose DTE Energy to risks related to commodity price movements, deviations in weather, and other related risks. DTE Energy's trading business routinely has speculative trading positions in the market, within strict policy guidelines DTE Energy sets, resulting from the management of DTE Energy's business portfolio. To the extent speculative trading positions exist, fluctuating commodity prices can improve or diminish DTE Energy's financial results and financial position. DTE Energy manages its exposure by establishing and enforcing strict risk limits and risk management procedures. During periods of extreme volatility, these risk limits and risk management procedures may not work as planned and cannot eliminate all risks associated with these activities.
Weather significantly affects operations. At both utilities, deviations from normal hot and cold weather conditions affect the Registrants' earnings and cash flows. Mild temperatures can result in decreased utilization of the Registrants' assets, lowering income and cash flows. At DTE Electric, ice storms, tornadoes, or high winds can damage the electric distribution system infrastructure and power generation facilities and require it to perform emergency repairs and incur material unplanned expenses. The expenses of storm restoration efforts may not be fully recoverable through the regulatory process. DTE Gas can experience higher than anticipated expenses from emergency repairs on its gas distribution infrastructure required as a result of weather related issues.
Unplanned power plant outages may be costly. Unforeseen maintenance may be required to safely produce electricity or comply with environmental regulations. As a result of unforeseen maintenance, the Registrants may be required to make spot market purchases of electricity that exceed the costs of generation. The Registrants' financial performance may be negatively affected if unable to recover such increased costs.
Regional, national, and international economic conditions can have an unfavorable impact on the Registrants. The Registrants' utility and DTE Energy's non-utility businesses follow the economic cycles of the customers they serve and credit risk of counterparties they do business with. Should the financial conditions of some of DTE Energy's significant customers deteriorate as a result of regional, national or international economic conditions, reduced volumes of electricity and gas, and demand for energy services DTE Energy supplies, collections of accounts receivable, reductions in federal and state energy assistance funding, and potentially higher levels of lost gas or stolen gas and electricity could result in decreased earnings and cash flows.
Renewable portfolio standards and energy waste reduction programs may affect the Registrants' business. The Registrants are subject to existing Michigan, and potential future, federal legislation and regulation requiring them to secure sources of renewable energy. The Registrants have complied with the existing federal and state legislation, but do not know what requirements may be added by federal or state legislation in the future. In addition, the Registrants expect to comply with new Michigan legislation increasing the percentage of power required to be provided by renewable energy sources. The Registrants cannot predict the financial impact or costs associated with complying with potential future legislation and regulations. Compliance with these requirements can significantly increase capital expenditures and operating expenses and can negatively affect the affordability of the rates charged to customers.
The Registrants are also required by Michigan legislation to implement energy waste reduction measures and provide energy waste reduction customer awareness and education programs. These requirements necessitate expenditures, and implementation of these programs creates the risk of reducing the Registrants' revenues as customers decrease their energy usage. The Registrants cannot predict how these programs will impact their business and future operating results.


Failure to attract and retain key executive officers and other skilled professional and technical employees could have an adverse effect on the Registrants operations. The Registrants' businesses are dependent on their ability to attract and retain skilled employees. Competition for skilled employees in some areas is high, and the inability to attract and retain these employees could adversely affect the Registrants' business and future operating results. In addition, the Registrants have an aging utility workforce, and the failure of a successful transfer of knowledge and expertise could negatively impact their operations.
A work interruption may adversely affect the Registrants. There are several bargaining units for DTE Energy's approximately 5,200 and DTE Electric's approximately 2,800 represented employees. The majority of represented employees are under contracts that expire in 2020 and 2021. A union choosing to strike would have an impact on the Registrants' businesses. The Registrants are unable to predict the effect a work stoppage would have on their costs of operations and financial performance.
DTE Energy's ability to utilize production tax credits may be limited. To reduce U.S. dependence on imported oil, the Internal Revenue Code provides production tax credits as an incentive for taxpayers to produce fuels and electricity from alternative sources. DTE Energy generated production tax credits from coke production, renewable gas recovery, reduced emission fuel, and gas production operations, and for the Registrants, renewable energy generation. If the Registrants' production tax credits were disallowed in whole or in part as a result of an IRS audit or changes in tax law, there could be additional tax liabilities owed for previously recognized tax credits that could significantly impact the Registrants' earnings and cash flows.
If DTE Energy's goodwill becomes impaired, it may be required to record a charge to earnings. DTE Energy annually reviews the carrying value of goodwill associated with acquisitions it has made for impairment. Factors that may be considered for purposes of this analysis include any change in circumstances indicating that the carrying value of DTE Energy goodwill may not be recoverable, such as a decline in stock price and market capitalization, future cash flows, and slower growth rates in the industry. DTE Energy cannot predict the timing, strength, or duration of any economic slowdown or subsequent recovery, worldwide or in the economy or markets in which it operates; however, when events or changes in circumstances indicate that the carrying value of these assets may not be recoverable, DTE Energy may take a non-cash impairment charge, which could potentially materially impact DTE Energy's results of operations and financial position.
The Registrants may not be fully covered by insurance. The Registrants have a comprehensive insurance program in place to provide coverage for various types of risks, including catastrophic damage as a result of severe weather or other natural disasters, war, terrorism, or a combination of other significant unforeseen events that could impact the Registrants' operations. Economic losses might not be covered in full by insurance, or the Registrants' insurers may be unable to meet contractual obligations.

Item 1B. Unresolved Staff Comments
None.



Item 3. Legal Proceedings
In March 2018, the Trenton Channel Power Plant experienced exceedances of its mercury emission limits. The exceedances were reported to the EPA and the MDEQ. On September 12, 2018, the EPA issued a NOV. DTE Electric is currently working with the EPA to address the NOV.  At this time, DTE Electric cannot predict the impact of the NOV.
For more information on legal proceedings and matters related to the Registrants, see Notes 9 and 18 to the Consolidated Financial Statements in Item 8 of this Report, "Regulatory Matters" and "Commitments and Contingencies," respectively.

Item 4. Mine Safety Disclosures
Not applicable.


Part II
Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters, and Issuer Purchases of Equity Securities
DTE Energy common stock is listed under the ticker symbol "DTE" on the New York Stock Exchange, which is the principal market for such stock.
At December 31, 2018, there were 181,925,281 shares of DTE Energy common stock outstanding. These shares were held by a total of 51,338 shareholders of record.
All of the 138,632,234 issued and outstanding shares of DTE Electric common stock, par value $10 per share, are owned by DTE Energy, and constitute 100% of the voting securities of DTE Electric. Therefore, no market exists for DTE Electric's common stock.
For information on DTE Energy dividend restrictions, see Note 16 to the Consolidated Financial Statements in Item 8 of this Report, "Short-Term Credit Arrangements and Borrowings."
All of DTE Energy's equity compensation plans that provide for the annual awarding of stock-based compensation have been approved by shareholders. For additional detail, see Note 21 to the Consolidated Financial Statements in Item 8 of this Report, "Stock-Based Compensation."
See the following table for information as of December 31, 2018:
 Number of Securities to be Issued Upon Exercise of Outstanding Options Weighted-Average Exercise Price of Outstanding Options Number of Securities Remaining Available for Future Issuance Under Equity Compensation Plans
Plans approved by shareholders52,100
 $43.30
 2,897,674
UNREGISTERED SALES OF DTE ENERGY EQUITY SECURITIES AND OTHERUSE OF PROCEEDS
DescriptionPurchases of DTE Energy Equity Securities by the Issuer and Affiliated Purchasers
The following table provides information about DTE Energy's purchases of equity securities that are registered by DTE Energy pursuant to Section 12 of the Exchange Act of 1934 for the quarter ended December 31, 2018:
 
Number of Shares Purchased(a)
 
Average Price
Paid per Share
(a)
 Number of Shares Purchased as Part of Publicly Announced
Plans or Programs
 Average Price Paid per Share Maximum Dollar
Value that May
Yet Be Purchased Under the Plans or Programs
10/01/2018 — 10/31/2018143
 $110.14
 
 
 
11/01/2018 — 11/30/2018
 $
 
 
 
12/01/2018 — 12/31/2018
 $
 
 
 
Total143
  
 
  
  

(a)Represents shares of DTE Energy common stock withheld to satisfy income tax obligations upon the vesting of restricted stock based on the price in effect at the grant date.


COMPARISON OF CUMULATIVE FIVE YEAR TOTAL RETURN
Total Return to DTE Energy Shareholders
(Includes reinvestment of dividends)
  Annual Return Percentage
Year Ended December 31,
Company/Index 2014 2015 2016 2017 2018
DTE Energy Company 34.61
 (3.77) 26.93
 14.59
 4.19
S&P 500 Index 13.69
 1.38
 11.95
 21.82
 (4.39)
S&P 500 Multi-Utilities Index 28.94
 (1.73) 18.56
 12.09
 1.77
  Indexed Returns
Year Ended December 31,
  Base Period          
Company/Index 2013 2014 2015 2016 2017 2018
DTE Energy Company 100.00
 134.61
 129.54
 164.41
 188.40
 196.30
S&P 500 Index 100.00
 113.69
 115.26
 129.04
 157.19
 150.29
S&P 500 Multi-Utilities Index 100.00
 128.94
 126.71
 150.22
 168.38
 171.35
dteenergy20_chart-06124a04.jpg



Item 6. Selected Financial Data
The following selected financial data of DTE Energy should be read in conjunction with the accompanying Management’s Discussion and Analysis in Item 7 of this Report and Combined Notes to Consolidated Financial Statements in Item 8 of this Report. This information has been omitted for DTE Electric per General Instruction I (2) (a) of Form 10-K for wholly-owned subsidiaries (reduced disclosure format).
 2018 2017 2016 2015 2014
 (In millions, except per share amounts)
Operating Revenues$14,212
 $12,607
 $10,630
 $10,337
 $12,301
Net Income Attributable to DTE Energy Company(a)
$1,120
 $1,134
 $868
 $727
 $905
Diluted Earnings Per Common Share$6.17
 $6.32
 $4.83
 $4.05
 $5.10
Financial Information         
Dividends declared per share of common stock$3.60
 $3.36
 $3.06
 $2.84
 $2.69
Total Assets$36,288
 $33,767
 $32,041
 $28,662
 $27,827
Long-Term Debt(b)
$12,134
 $12,185
 $11,269
 $8,760
 $8,271
Shareholders’ equity$10,237
 $9,512
 $9,011
 $8,772
 $8,327

(a)The 2017 results include a $105 million net income tax benefit related to the enactment of the TCJA.
(b)Long-Term Debt includes Capital lease obligations and excludes debt due within one year.

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations
The following combined discussion is separately filed by DTE Energy and DTE Electric. However, DTE Electric does not make any representations as to information related solely to DTE Energy or the subsidiaries of DTE Energy other than itself.
EXECUTIVE OVERVIEW
DTE Energy is a diversified energy company with 2018 Operating Revenues of approximately $14.2 billion and Total Assets of approximately $36.3 billion. DTE Energy is the parent company of DTE Electric and DTE Gas, regulated electric and natural gas utilities engaged primarily in the business of providing electricity and natural gas sales, distribution, and storage services throughout Michigan. DTE Energy operates three energy-related non-utility segments with operations throughout the United States.
The following table summarizes DTE Energy's financial results:
 Years Ended December 31,
 2018 2017 2016
 (In millions, except per share amounts)
Net Income Attributable to DTE Energy Company$1,120
 $1,134
 $868
Diluted Earnings per Common Share$6.17
 $6.32
 $4.83
The decrease in 2018 Net Income Attributable to DTE Energy Company was primarily due to lower earnings in the Gas Storage and Pipelines, Energy Trading, and Corporate and Other includes various holding company activities, holds certainsegments, partially offset by higher earnings in the Electric, Gas, and Power and Industrial Projects segments. The 2018 decrease was partially attributable to true-up adjustments for the remeasurement of deferred taxes of $21 million as the adjustments increased Income Tax Expense, of which $17 million was attributable to the regulated utilities and increased Regulatory liabilities. The increase in 2017 Net Income Attributable to DTE Energy Company was primarily due to higher earnings in the Gas Storage and Pipelines, Energy Trading, and Power and Industrial Projects segments, partially offset by lower earnings in the Corporate and Other segment. The 2017 increase was also due to $105 million of net income tax benefit related to the enactment of the TCJA.
Please see detailed explanations of segment performance in the following "Results of Operations" section.
DTE Energy's strategy is to achieve long-term earnings growth, a strong balance sheet, and an attractive dividend yield.


DTE Energy's utilities are investing capital to improve customer reliability through investments in base infrastructure and new generation, and to comply with environmental requirements. DTE Energy expects that planned significant capital investments will result in earnings growth. DTE Energy is focused on executing plans to achieve operational excellence and customer satisfaction with a focus on customer affordability. DTE Energy operates in a constructive regulatory environment and has solid relationships with its regulators.
In May 2017, DTE Energy announced its plan to reduce carbon emissions. This goal will be attained by cutting carbon emissions 30% by the early 2020s, 45% by 2030, 75% by 2040, and more than 80% by 2050. To achieve this reduction, DTE Energy will transition away from coal-powered sources and incorporate more renewable energy, energy waste reduction projects, demand response, and natural gas fueled generation. DTE Energy has already begun the transition in the way it produces power through the continued retirement of its aging coal-fired plants. In May 2018, DTE Energy announced its plans to accelerate its clean energy initiatives by targeting at least a 50% clean energy goal by 2030 to be achieved through a combination of investments in renewable energy and energy waste reduction projects. Refer to the "Capital Investments" section below for further discussion.
DTE Energy has significant investments in non-utility businesses. DTE Energy employs disciplined investment criteria when assessing growth opportunities that leverage its assets, skills, and expertise, and provides diversity in earnings and geography. Specifically, DTE Energy invests in targeted energy markets with attractive competitive dynamics where meaningful scale is in alignment with its risk profile. DTE Energy expects growth opportunities in the Gas Storage and Pipelines and Power and Industrial Projects segments.
A key priority for DTE Energy is to maintain a strong balance sheet which facilitates access to capital markets and reasonably priced short-term and long-term financing. Near-term growth will be funded through internally generated cash flows and the issuance of debt and energy-related investments.equity. DTE Energy has an enterprise risk management program that, among other things, is designed to monitor and manage exposure to earnings and cash flow volatility related to commodity price changes, interest rates, and counterparty credit risk.
CAPITAL INVESTMENTS
DTE Energy's utility businesses require significant capital investments to maintain and improve the electric generation and electric and natural gas distribution infrastructure and to comply with environmental regulations and renewable energy requirements.
DTE Electric's capital investments over the 2019-2023 period are estimated at $11.3 billion comprised of $4.0 billion for capital replacements and other projects, $4.6 billion for distribution infrastructure, and $2.7 billion for new generation. DTE Electric has retired four coal-fired generation units at the Trenton Channel, River Rouge, and St Clair facilities and has announced plans to retire its remaining thirteen coal-fired generating units. Seven of these coal-fired generating units will be retired through 2023 at the Trenton Channel, River Rouge, and St. Clair facilities. The remaining coal-fired generating units at the Belle River and Monroe facilities are expected to be retired by 2040. The retired facilities will be replaced with renewables, energy waste reduction, demand response, and natural gas fueled generation. In April 2018, DTE Electric received approval from the MPSC to build a natural gas fueled combined cycle generation facility to provide approximately 1,100 megawatts of energy beginning in 2022. In August 2018, DTE Electric began construction on its natural gas fueled combined cycle generation facility. In March 2018, DTE Electric filed its 2018 Renewable Energy Plan with the MPSC proposing approximately 1,000 additional megawatts of energy from new wind and solar projects to be completed by 2022. The MPSC had previously approved 300 of the 1,000 additional megawatts for wind projects in an MPSC order received in September 2016. In January 2018, DTE Electric filed with the MPSC its five-year distribution operations investment and maintenance plan to improve system reliability. DTE Electric plans to seek regulatory approval for capital expenditures consistent with prior ratemaking treatment. For further discussion of regulatory matters, see Note 9 to the Consolidated Financial Statements, "Regulatory Matters."
DTE Gas' capital investments over the 2019-2023 period are estimated at $2.5 billion comprised of $1.2 billion for base infrastructure, and $1.3 billion for gas main renewal, meter move out, and pipeline integrity programs. DTE Gas plans to seek regulatory approval for capital expenditures consistent with ratemaking treatment.
DTE Energy's non-utility businesses' capital investments are primarily for expansion, growth, and ongoing maintenance. Gas Storage and Pipelines' capital investments over the 2019-2023 period are estimated at $4.0 billion to $5.0 billion for gathering and pipeline investments and expansions. Power and Industrial Projects' capital investments over the 2019-2023 period are estimated at $1.0 billion to $1.4 billion for industrial energy services and RNG projects.


ENVIRONMENTAL MATTERS
The Registrants are subject to extensive environmental regulation and expect to continue recovering environmental costs related to utility operations through rates charged to customers. The following table summarizes DTE Energy's, including DTE Electric's, estimated significant future environmental expenditures based upon current regulations. The amounts reported in the following table do not include any expenditures related to the EPA Clean Power Plan as discussed below. Actual costs to comply could vary substantially.regulation. Additional costs may result as the effects of various substances on the environment are studied and governmental regulations are developed and implemented.
 DTE Electric DTE Gas Non-utility Total
 (In millions)
Air$40
 $
 $
 $40
Water90
 
 
 90
Contaminated and other sites10
 20
 
 30
Coal Combustion Residuals and Effluent Limitations Guidelines290
 
 
 290
Estimated total future expenditures through 2022$430
 $20
 $
 $450
Estimated 2016 expenditures$70
 $7
 $
 $77
Estimated 2017 expenditures$40
 $4
 $
 $44
Actual costs to comply could vary substantially. The Registrants expect to continue recovering environmental costs related to utility operations through rates charged to customers, as authorized by the MPSC.
Air — DTE Electric is subject to the EPA ozone and fine particulate transport and acid rain regulations that limit power plant emissions of sulfur dioxideSO2 and nitrogen oxides.NOX. The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to additional emission controls on fossil-fueled power plants to reduce nitrogen oxide and sulfur dioxide, with further emission controls planned for reductions ofSO2, NOX, mercury, and other emissions. TheseAdditional rulemakings may occur over the next few years which could require additional controls for sulfur dioxide, nitrogen oxides,SO2, NOX, and other hazardous air pollutants over the next few years.pollutants. To comply with existing requirements, DTE Electric spent approximately $2.4 billion through 2018. DTE Electric does not anticipate additional capital expenditures through 2025.

16



The EPA is implementinghas implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, in 2015 the EPA has finalized performance standards for emissions of carbon dioxide from new and existing electric generating units (EGUs).EGUs. In February 2016, the U.S. Supreme Court granted petitioners' requests for a stay of the carbon rules for existing EGUs (also known as the EPA Clean Power Plan) pending final review by the courts. The carbon standards for new sources are not expected to have a material impact on DTE Electric, since DTE ElectricClean Power Plan has no planslegal effect while the stay is in place. On March 28, 2017, a presidential executive order was issued on "Promoting Energy Independence and Economic Growth." The order instructs the EPA to build new coal-fired generationreview, and any potential new gas generation will be ableif appropriate, suspend, revise or rescind the Clean Power Plan rule. Following the issuance of this order, the federal government requested the U.S. Court of Appeals for the D.C. Circuit to comply withhold all legal challenges in abeyance until the standards.review of these regulations is completed. On October 10, 2017, the EPA proposed to rescind the Clean Power Plan and announced its intent to issue an ANPR seeking input as to whether it should replace the rule and, if so, what form it should take. In August 2018, the EPA proposed revised emission guidelines for GHGs from existing electric utility generating units. The proposed rule, named the Affordable Clean Energy (ACE) rule, is intended to replace the Clean Power Plan rule. Comments on the proposed ACE rule were due on October 31, 2018. It is not possible to determine the potential impact of the final carbon standards (also known as the EPA Clean Power Plan)EPA's proposed ACE rule on existing sources at this time.
Pending or future legislation or other regulatory actions could have a material impact on DTE Electric's operations and financial position and the rates charged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. DTE Electric would seek to recover these incremental costs through increased rates charged to its utility customers, as authorized by the MPSC.
Water — The EPA finalized regulations on cooling water intake in August 2014.Increased costs for energy produced from traditional coal-based sources due to recent, pending, and future regulatory initiatives, could also increase the economic viability of energy produced from renewable, natural gas fueled generation, and/or nuclear sources, energy waste reduction initiatives, and the potential development of market-based trading of carbon instruments which could provide new business opportunities for DTE ElectricEnergy's utility and non-utility segments. At the present time, it is conducting studiesnot possible to determinequantify the best technology for reducing the environmentalfinancial impacts of these climate related regulatory initiatives on the cooling water intake structures at each of its facilities. DTE Electric may be required to install technologies to reduce the impacts of the cooling water intakes.
Contaminated and Other Sites — Prior to the construction of major interstate natural gas pipelines, gas for heating and other uses was manufactured locally from processes involving coal, coke,Registrants or oil. The facilities, which produced gas, have been designated as MGP sites. DTE Gas owns, or previously owned, fourteen such former MGP sites. DTE Electric owns, or previously owned, three former MGP sites. DTE Energy anticipates the cost amortization methodology approved by the MPSC for DTE Gas, which allows DTE Gas to amortize the MGP costs over a ten-year period beginning with the year subsequent to the year the MGP costs were incurred, will prevent environmental costs from having a material adverse effect on DTE Energy's operations. DTE Electric believes the likelihood of a material change to the accrued amount is remote based on current knowledge of the conditions at each of its sites.
The Registrants are also in the process of cleaning up other sites where contamination is present as a result of historical and ongoing utility operations. These other sites include an engineered ash storage facility, electric distribution substations, gas pipelines, electric generating power plants, and underground and aboveground storage tank locations. Cleanup activities associated with these sites will be conducted over the next several years. Any significant change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for these sites and affect the Registrants' financial position and cash flows and the rates charged to their customers.
Coal Combustion ResidualsSee Items 1. and Effluent Limitations Guidelines— In April 2015, the EPA published a final rule for the disposal of coal combustion residuals, commonly known as coal ash. The rule became effective in October 2015. The rule is based on the continued listing of coal ash as a non-hazardous waste2. Business and relies on various self-implementation designProperties and performance standards. DTE Electric owns and operates 3 permitted engineered coal ash storage facilities to dispose of coal ash from coal-fired power plants and operates a number of smaller impoundments at its power plants. At certain facilities, the rule requires the installation of monitoring wells, compliance with groundwater standards, and the closure of basins at the end of the useful life of the associated power plant. At other facilities, the rule requires ash laden waters be moved from earthen basins to steel and concrete tanks.
In November 2015, the EPA finalized effluent limitations guidelines for the steam electric power generating industry which may require additional controls to be installed between 2018 and 2023. The initial costs to comply with this rule have been developed and included in the Coal Combustion Residual and Effluent Limitations Guidelines amount in the above table.

See Management’s Discussion and Analysis in Item 7 of this Report and Notes 7, 8, and 17Note 18 to the Consolidated Financial Statements in Item 8 of this Report, "Regulatory Matters", "Asset Retirement Obligations", and "Commitments and Contingencies".Contingencies," for further discussion of Environmental Matters.


OUTLOOK
The next few years will be a period of rapid change for DTE Energy and for the energy industry. DTE Energy's strong utility base, combined with its integrated non-utility operations, position it well for long-term growth.
Looking forward, DTE Energy will focus on several areas that are expected to improve future performance:
electric and gas customer satisfaction;
electric distribution system reliability;
new electric generation;
gas distribution system renewal;
rate competitiveness and affordability;
regulatory stability and investment recovery for the electric and gas utilities;
employee safety and engagement;
cost structure optimization across all business segments;
cash, capital, and liquidity to maintain or improve financial strength; and
investments that integrate assets and leverage skills and expertise.
DTE Energy will continue to pursue opportunities to grow its businesses in a disciplined manner if it can secure opportunities that meet its strategic, financial, and risk criteria.

RESULTS OF OPERATIONS
Management’s Discussion and Analysis of Financial Condition and Results of Operations includes financial information prepared in accordance with GAAP, as well as the non-GAAP financial measures, Utility Margin and Non-utility Margin, discussed below, which DTE Energy uses as measures of its operational performance. Generally, a non-GAAP financial measure is a numerical measure of financial performance, financial position or cash flows that excludes (or includes) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP.
DTE Energy uses Utility Margin and Non-utility Margin, non-GAAP financial measures, to assess its performance by reportable segment.
Utility Margin includes electric and gas Operating Revenues net of Fuel, purchased power, and gas expenses. The utilities’ fuel, purchased power, and natural gas supply are passed through to customers, and therefore, result in changes to the utilities’ revenues that are comparable to changes in such expenses. As such, DTE Energy believes Utility Margin provides a meaningful basis for evaluating the utilities’ operations across periods, as it excludes the revenue effect of fluctuations in these expenses.
The Non-utility Margin relates to the Power and Industrial Projects and Energy Trading segments. For the Power and Industrial Projects segment, Non-utility Margin primarily includes Operating Revenues net of Fuel, purchased power, and gas expenses. Operating Revenues include sales of refined coal to third parties and the affiliated Electric utility, metallurgical coke and related by-products, petroleum coke, renewable natural gas, and electricity, as well as rental income and revenues from utility-type consulting, management, and operational services. For the Energy Trading segment, Non-utility Margin includes revenue and realized and unrealized gains and losses from physical and financial power and gas marketing, optimization, and trading activities, net of Purchased power and gas related to these activities. DTE Energy evaluates its operating performance of these non-utility businesses using the measure of Operating Revenues net of Fuel, purchased power, and gas expenses.


Utility Margin and Non-utility Margin are not measures calculated in accordance with GAAP and should be viewed as a supplement to and not a substitute for the results of operations presented in accordance with GAAP. Utility Margin and Non-utility Margin do not intend to represent operating income, the most comparable GAAP measure, as an indicator of operating performance and are not necessarily comparable to similarly titled measures reported by other companies.
The following sections provide a detailed discussion of the operating performance and future outlook of DTE Energy's segments. Segment information, described below, includes intercompany revenues and expenses, and other income and deductions that are eliminated in the Consolidated Financial Statements.
 2018 2017 2016
 (In millions)
Net Income (Loss) Attributable to DTE Energy by Segment     
Electric$664
 $606
 $622
Gas150
 146
 138
Gas Storage and Pipelines235
 275
 119
Power and Industrial Projects161
 138
 95
Energy Trading39
 72
 (45)
Corporate and Other(129) (103) (61)
Net Income Attributable to DTE Energy Company$1,120
 $1,134
 $868
ELECTRIC
The Results of Operations discussion for DTE Electric is presented in a reduced disclosure format in accordance with General Instruction I (2) (a) of Form 10-K for wholly-owned subsidiaries.
The Electric segment consists principally of DTE Electric. Electric results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Utility operations$5,298
 $5,102
 $5,225
Fuel and purchased power — utility1,552
 1,454
 1,532
Utility Margin3,746
 3,648
 3,693
Operation and maintenance1,437
 1,382
 1,408
Depreciation and amortization836
 753
 750
Taxes other than income307
 302
 284
Asset (gains) losses and impairments, net(1) 
 
Operating Income1,167
 1,211
 1,251
Other (Income) and Deductions310
 284
 276
Income Tax Expense193
 321
 353
Net Income Attributable to DTE Energy Company$664
 $606
 $622
See DTE Electric's Consolidated Statements of Operations in Item 8 of this Report for a complete view of its results. For an explanation of differences between the Electric segment and DTE Electric's Consolidated Statements of Operations, refer to Note 20 to the Consolidated Financial Statements, "Retirement Benefits and Trusteed Assets."
Utility Margin increased $98 million in 2018 and decreased $45 million in 2017. Revenues associated with certain mechanisms and surcharges are offset by related expenses elsewhere in the Registrants' Consolidated Statements of Operations.


The following table details changes in various Utility Margin components relative to the comparable prior period:
 2018 2017
 (In millions)
Weather$152
 $(109)
Implementation of new rates51
 124
Regulatory mechanism — TRM40
 (26)
PSCR disallowance in 201713
 (13)
Base sales(3) (26)
TCJA rate reduction(156) 
Other regulatory mechanisms and other1
 5
Increase (decrease) in Utility Margin$98
 $(45)
 2018 2017 2016
 (In thousands of MWh)
DTE Electric Sales     
Residential15,959
 14,885
 15,875
Commercial17,282
 17,283
 17,521
Industrial10,324
 9,897
 10,004
Other221
 258
 264
 43,786
 42,323
 43,664
Interconnection sales(a)
2,796
 2,623
 2,334
Total DTE Electric Sales46,582
 44,946
 45,998
      
DTE Electric Deliveries     
Retail and wholesale43,786
 42,323
 43,664
Electric retail access, including self-generators(b)
4,737
 4,820
 4,936
Total DTE Electric Sales and Deliveries48,523
 47,143
 48,600

(a)Represents power that is not distributed by DTE Electric.
(b)Represents deliveries for self-generators that have purchased power from alternative energy suppliers to supplement their power requirements.
DTE Electric sales increased for residential, commercial, and industrial primarily due to favorable weather in 2018.
Operation and maintenance expense increased $55 million in 2018 and decreased $26 million in 2017. The increase in 2018 was primarily due to increased uncollectible expense of $34 million due to customer billing initiatives following implementation of the new billing system, increased power plant generation expense of $24 million, an increase in energy waste reduction expense of $10 million to meet higher energy savings targets, partially offset by decreased distribution operations expense of $13 million. The decrease in 2017 was primarily due to decreased power plant generation expenses of $66 million, partially offset by increased storm restoration expenses of $27 million, and increased line clearance expenses of $10 million. The decrease in power plant generation includes an increase of $6 million of costs related to the 2016 fire at a generation facility, offset by $21 million of insurance proceeds received in 2017.
Depreciation and amortization expense increased $83 million in 2018 and increased $3 million in 2017. In 2018, the increase was primarily due to an increase to depreciable base of $46 million and an increase of $42 million associated with the TRM, partially offset by a decrease in regulatory asset amortization of $5 million. In 2017, the increase was due to $45 million of increased expense from an increased depreciable base, partially offset by a decrease of $29 million associated with the TRM, and a decrease of $13 million in amortization of regulatory assets.


Other (Income) and Deductions increased $26 million in 2018 and increased $8 million in 2017. The increase in 2018 was primarily due to higher interest expense of $9 million and change in investment earnings (loss of $11 million in 2018 compared to a gain of $26 million in 2017), partially offset by decreased non-operating retirement benefits expense of $13 million and a contribution to the DTE Energy Foundation of $7 million in 2017. The increase in 2017 was primarily due to higher interest expense of $10 million, lower interest income of $8 million related to a sales and use tax settlement received in 2016, and a $7 million contribution to the DTE Energy Foundation, partially offset by $12 million of higher investment earnings and a $3 million decrease in Low Income Self-Sufficiency Plan (LSP) contributions to not-for-profit organizations in 2016.
Outlook DTE Electric will continue to move forward in its efforts to achieve operational excellence, sustain strong cash flows, and earn its authorized return on equity. DTE Electric expects that planned significant capital investments will result in earnings growth. DTE Electric will maintain a strong focus on customers by increasing reliability and satisfaction while keeping customer rate increases affordable. Looking forward, additional factors may impact earnings such as weather, the outcome of regulatory proceedings, benefit plan design changes, investment returns and changes in discount rate assumptions in benefit plans and health care costs, uncertainty of legislative or regulatory actions regarding climate change, and effects of energy waste reduction programs.
DTE Electric filed a rate case with the MPSC on July 6, 2018 requesting an increase in base rates of $328 million based on a projected twelve-month period ending April 30, 2020. The requested increase in base rates is primarily due to an increase in net plant resulting from infrastructure investments, depreciation expense, as requested in the 2016 DTE Electric Depreciation Case Filing, and reliability improvement projects. The rate filing also requests an increase in return on equity from 10.0% to 10.5% and includes projected changes in sales, operation and maintenance expenses, and working capital. In addition, the rate filing requests an Infrastructure Recovery Mechanism to recover the incremental revenue requirement associated with certain distribution, fossil generation, and nuclear generation capital expenditures through 2022. DTE Electric also included Calculation C in this filing to address all remaining issues relative to the enactment of the TCJA, which is primarily the remeasurement of deferred taxes and how the amounts deferred as Regulatory liabilities will flow to ratepayers. A final MPSC order in this case is expected by May 2019. Refer to Note 9 to the Consolidated Financial Statements, “Regulatory Matters” for additional information.
GAS
The Gas segment consists principally of DTE Gas. Gas results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Utility operations$1,436
 $1,388
 $1,324
Cost of gas — utility446
 443
 454
Utility Margin990
 945
 870
Operation and maintenance502
 449
 440
Depreciation and amortization133
 123
 106
Taxes other than income73
 65
 64
Asset (gains) losses and impairments, net
 
 4
Operating Income282
 308
 256
Other (Income) and Deductions65
 84
 41
Income Tax Expense67
 78
 77
Net Income Attributable to DTE Energy Company$150
 $146
 $138
Utility Margin increased $45 million in 2018 and increased $75 million in 2017. Revenues associated with certain surcharges are offset by related expenses elsewhere in DTE Energy's Consolidated Statements of Operations.


The following table details changes in various Utility Margin components relative to the comparable prior period:
 2018 2017
 (In millions)
Weather$46
 $(6)
Implementation of new rates15
 80
Midstream storage and transportation revenues15
 (5)
Regulatory mechanism — RDM(3) 4
TCJA rate reduction(40) 
Other regulatory mechanisms and other12
 2
Increase in Utility Margin$45
 $75
 2018 2017 2016
 (In Bcf)
Gas Markets     
Gas sales135
 119
 116
End-user transportation187
 165
 182
 322
 284
 298
Intermediate transportation329
 260
 214
Total Gas sales651
 544
 512
Operation and maintenance expense increased $53 million in 2018 and increased $9 million in 2017. The increase in 2018 was primarily due to increased uncollectible expense of $28 million due to customer billing initiatives following implementation of a new customer billing system and higher gas operations expenses of $22 million, which included increased investment spending and higher pipeline integrity expenses. The increase in 2017 was primarily due to increased corporate expenses of $3 million and increased gas operations expenses of $3 million.
Depreciation and amortization expense increased $10 million in 2018 and increased $17 million in 2017. The increase in 2018 was primarily due to an increased depreciable base. The increase in 2017 was primarily due to an increased depreciable base and higher depreciation rates.
Other (Income) and Deductions decreased $19 million in 2018 and increased $43 million in 2017. The decrease in 2018 was primarily due to lower contributions to the DTE Energy Foundation and other not-for-profit organizations of $27 million, partially offset by higher net interest expense of $6 million. The increase in 2017 was primarily due to increased non-operating retirement benefits expenses of $31 million, increased contributions to the DTE Energy Foundation and other not-for-profit organizations of $7 million and higher interest expense of $5 million.
Outlook — DTE Gas will continue to move forward in its efforts to achieve operational excellence, sustain strong cash flows, and earn its authorized return on equity. DTE Gas expects that planned significant infrastructure capital investments will result in earnings growth. Looking forward, additional factors may impact earnings such as weather, the outcome of regulatory proceedings, benefit plan design changes, and investment returns and changes in discount rate assumptions in benefit plans and health care costs. DTE Gas expects to continue its efforts to improve productivity and decrease costs while improving customer satisfaction with consideration of customer rate affordability.
DTE filed its Calculation C case with the MPSC on November 16, 2018 to reduce the revenue requirement by $12 million related to the amortization of deferred tax remeasurement. Calculation C addresses all remaining issues relative to the enactment of the TCJA, which is primarily the remeasurement of deferred taxes and how the amounts deferred as Regulatory liabilities will flow to ratepayers. Refer to Note 9 to the Consolidated Financial Statements, “Regulatory Matters” for additional information.


GAS STORAGE AND PIPELINES
The Gas Storage and Pipelines segment consists of the non-utility gas pipelines and storage businesses. Gas Storage and Pipelines results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Non-utility operations$485
 $453
 $302
Cost of gas — Non-utility22
 30
 6
Operation and maintenance103
 83
 81
Depreciation and amortization82
 76
 45
Taxes other than income8
 8
 4
Asset (gains) losses and impairments, net
 2
 
Operating Income270
 254
 166
Other (Income) and Deductions(61) (18) (31)
Income Tax Expense (Benefit)68
 (30) 71
Net Income263
 302
 126
Less: Net Income Attributable to Noncontrolling Interests28
 27
 7
Net Income Attributable to DTE Energy Company$235
 $275
 $119
Operating Revenues — Non-utility operations increased $32 million in 2018 and increased $151 million in 2017. The increase in both periods was primarily due to increased pipeline and gathering volumes. The 2017 increase was also due to the acquisition of AGS and SGG in October 2016.
Cost of gas — Non-utility decreased $8 million in 2018 and increased $24 million in 2017. The 2018 decrease was driven by lower physical purchases of gas from AGS customers for resale to optimize available transportation capacity. The 2017 increase was driven by higher physical purchases of gas from AGS customers for resale to optimize available transportation capacity.
Operation and maintenance expense increased $20 million in 2018 and increased $2 million in 2017. The 2018 increase was primarily due to increased labor related expenses and additional compression activity on the Bluestone Pipeline and Susquehanna gathering systems.
Depreciation and amortization expense increased $6 million in 2018 and increased $31 million in 2017. The 2017 increase was primarily due to the acquisition of AGS and SGG in October 2016.
Other (Income) and Deductions increased $43 million in 2018 and decreased $13 million in 2017. The 2018 increase was primarily due to increased earnings from pipeline investments and a $16 million net loss on extinguishment of debt within the storage business in 2017, partially offset by higher interest expense. The 2017 decrease was primarily due to a $16 million net loss on extinguishment of debt within the storage business and contributions to the DTE Energy Foundation and other not-for-profit organizations, partially offset by increased earnings from pipeline investments.
Income Tax Expense (Benefit) increased $98 million in 2018 and decreased $101 million in 2017. The changes were primarily driven by the $115 million remeasurement of deferred tax assets and liabilities to reflect the reduction in the corporate tax rate from the enactment of the TCJA in December 2017. The 2017 change was partially offset by increased tax expense on higher earnings in 2017.
Net Income Attributable to Noncontrolling Interests increased $1 million in 2018 and increased $20 million in 2017. The 2017 increase was primarily due to the acquisition of SGG in October 2016.
Outlook — DTE Energy believes its long-term agreements with producers and the quality of the natural gas reserves in the Marcellus/Utica region soundly position the gathering systems for future revenues.
NEXUS Pipeline was placed in service in in October 2018. The NEXUS Pipeline provides a transportation path for Appalachian Basin shale gas, including Utica and Marcellus shale gas, directly to consuming markets in northern Ohio, southeastern Michigan, and Dawn Ontario. DTE Energy owns a 50% partnership interest in the NEXUS Pipeline with an investment balance of $1.26 billion at December 31, 2018.


On January 11, 2019, NEXUS signed an agreement to purchase Generation Pipeline, LLC, a public utility regulated by the Public Utilities Commission of Ohio. This 23-mile pipeline system supplies gas to industrial customers in the Toledo, OH area, has existing interconnects with ANR Pipeline Company and Panhandle Eastern Pipeline Company, and is located 4 miles away from Nexus. The transaction is expected to close in the first half of 2019 upon regulatory approvals.
AGS and SGG provide a platform for midstream growth and access to further investment opportunities in the Appalachian basin, an additional connection to the NEXUS Pipeline which should drive incremental volumes on the NEXUS Pipeline, and producer relationships that may lead to more partnering opportunities.
Gas Storage and Pipelines expects to maintain its steady growth by developing an asset portfolio with multiple growth platforms through investment in new projects and expansions. Gas Storage and Pipelines will continue to look for additional investment opportunities and other storage and pipeline projects at favorable prices.
POWER AND INDUSTRIAL PROJECTS
The Power and Industrial Projects segment is comprised primarily of projects that deliver energy and utility-type products and services to industrial, commercial, and institutional customers, produce reduced emissions fuel, and sell electricity and pipeline-quality gas from renewable energy projects. Power and Industrial Projects results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Non-utility operations$2,204
 $2,089
 $1,906
Fuel, purchased power, and gas — non-utility1,888
 1,813
 1,640
Non-utility Margin316
 276
 266
Operation and maintenance363
 342
 317
Depreciation and amortization67
 72
 72
Taxes other than income12
 11
 13
Asset (gains) losses and impairments, net27
 20
 (1)
Operating Loss(153) (169) (135)
Other (Income) and Deductions(89) (63) (49)
Income Taxes     
Benefit(7) (42) (26)
Production Tax Credits(188) (153) (114)
 (195) (195) (140)
Net Income131
 89
 54
Less: Net Loss Attributable to Noncontrolling Interests(30) (49) (41)
Net Income Attributable to DTE Energy Company$161
 $138
 $95


Operating Revenues — Non-utility operations increased $115 million in 2018 and increased $183 million in 2017. The changes are due to the following:
 2018
 (In millions)
Higher demand due to improved conditions in the steel business$59
Higher production in the renewables business25
Higher production, offset by lower coal prices in the REF business18
Higher sales primarily associated with new contracts in the on-site business13
 $115
  
 2017
 (In millions)
Higher demand due to improved conditions in the steel business$107
Higher production driven by new projects, offset by lower coal prices in the REF business102
Lower production and one-time recovery in 2016, offset by an acquisition in the renewables business(9)
Lower sales primarily associated with expired contracts in the on-site business(17)
 $183
Non-utility Margin increased $40 million in 2018 and increased $10 million in 2017. The changes are due to the following:
 2018
 (In millions)
Higher production in the renewables business$20
Higher sales primarily associated with new contracts in the on-site business12
Higher demand due to improved conditions in the steel business8
 $40
  
 2017
 (In millions)
Higher demand due to improved conditions in the steel business$42
Lower production and one-time recovery in 2016 in the renewables business(11)
Lower sales primarily associated with expired contracts in the on-site business(15)
Other(6)
 $10
Operation and maintenance expense increased $21 million in 2018 and increased $25 million in 2017. The 2018 increase was primarily due to higher production in the REF business of $11 million and new contracts in the on-site business of $8 million. The 2017 increase was primarily due to an increase in maintenance spending driven by improved conditions in the steel business of $16 million, higher maintenance and a new acquisition in the renewables business of $7 million, and an increase associated with new projects in the REF business of $5 million, offset by lower spending as a result of Shenango plant closure activities in the first half of 2016 of $6 million.
Asset (gains) losses and impairments, net increased $7 million in 2018 from the net loss of $20 million in 2017 and decreased $21 million in 2017 from the net gain of $1 million in 2016. The 2018 increase was primarily due to $15 million of a liability adjustment related to contingent consideration and an $8 million asset write-off associated with the renewable business in anticipation of a contract ending in 2020. The 2017 decrease was primarily due to an impairment in the REF business of $14 million and an impairment of a petroleum coke project of $6 million.


Other (Income) and Deductions increased $26 million in 2018 and increased $14 million in 2017. The 2018 increase was primarily due to higher production in the REF business of $20 million and decreased contributions to the DTE Energy Foundation of $4 million. The 2017 increase was primarily due to increased equity earnings in the renewable business of $9 million and insurance settlements in the renewable and REF businesses of $6 million, offset by increased contributions to the DTE Energy Foundation of $6 million.
Income Taxes — Benefit decreased by $35 million in 2018 and increased by $16 million in 2017. The 2018 decrease was primarily due to the 2017 remeasurement of deferred tax assets and liabilities to reflect the reduction in the corporate tax rate from the enactment of the TCJA in December 2017. The increase in 2017 was primarily due to the remeasurement of deferred tax assets and liabilities to reflect the reduction in the corporate tax rate from the enactment of the TCJA in December 2017 of $21 million, an increase due to higher pretax loss of $7 million, and a decrease due to a worthless stock deduction associated with the Shenango closure in 2016 of $10 million.
Income Taxes — Production Tax Credits increased by $35 million in 2018 and increased $39 million in 2017. The increase in both periods was primarily due to higher production in the REF business.
Net Loss Attributable to Noncontrolling Interests decreased by $19 million in 2018 and increased by $8 million in 2017. The 2018 decrease was primarily due to termination of a project in the REF business. The 2017 increase was primarily due to a change in the ownership percentage in one of the REF projects of $8 million.
Outlook — Power and Industrial Projects has constructed and placed in service REF facilities at ten sites including facilities located at seven third-party owned coal-fired power plants. DTE Energy has sold membership interests in five of the facilities and entered into lease arrangements in three of the facilities. Three REF facilities will phase out in 2019 with the remaining seven to be phased out at the end of 2021.
Power and Industrial Projects will continue to leverage its extensive energy-related operating experience and project management capability to develop additional energy projects to serve energy intensive industrial customers.
ENERGY TRADING
Energy Trading focuses on physical and financial power and natural gas marketing and trading, structured transactions, enhancement of returns from its asset portfolio, and optimization of contracted natural gas pipeline transportation and storage positions. Energy Trading also provides natural gas, power, and related services, which may include the management of associated storage and transportation contracts on the customers' behalf, and the supply or purchase of renewable energy credits to various customers. Energy Trading results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Non-utility operations$5,557
 $4,277
 $2,575
Purchased power and gas — non-utility5,417
 4,077
 2,552
Non-utility Margin140
 200
 23
Operation and maintenance75
 68
 63
Depreciation and amortization5
 5
 3
Taxes other than income5
 4
 2
Operating Income (Loss)55
 123
 (45)
Other (Income) and Deductions3
 2
 29
Income Tax Expense (Benefit)13
 49
 (29)
Net Income (Loss) Attributable to DTE Energy Company$39
 $72
 $(45)
Operating Revenues — Non-utility operations and Purchased power and gas — non-utility were impacted primarily by an increase in volumes as well as an increase in gas prices for the years ended December 31, 2018 and December 31, 2017, primarily in the gas structured strategy.


Non-utility Margin decreased $60 million in 2018 and increased $177 million in 2017. The change in both periods was primarily due to timing from the unrealized and realized margins presented in the following tables:
 2018
 (In millions)
Unrealized Margins(a)
 
Favorable results, primarily in the power trading strategy$20
Unfavorable results, primarily in gas structured, and power full requirements strategies(b)
(100)
 (80)
Realized Margins(a)
 
Favorable results, primarily in the gas structured strategy54
Unfavorable results, primarily in the power full requirements strategy(c)
(34)
 20
Decrease in Non-utility Margin$(60)

(a)Natural gas structured transactions typically involve a physical purchase or sale of natural gas in the future and/or natural gas basis financial instruments which are derivatives and a related non-derivative pipeline transportation contract. These gas structured transactions can result in significant earnings volatility as the derivative components are marked-to-market without revaluing the related non-derivative contracts.
(b)Amount includes $74 million of timing related losses related to gas strategies which will reverse in future periods as the underlying contracts settle.
(c)Amount includes $11 million of timing related gains related to gas strategies recognized in previous periods that reversed as the underlying contracts settled.
 2017
 (In millions)
Unrealized Margins(a)
 
Favorable results, primarily in gas structured and gas full requirements strategies(b)
$113
Unfavorable results, primarily in power and gas trading and power full requirements strategies(26)
 87
Realized Margins(a)
 
Favorable results, primarily in gas structured, environmental trading and gas storage strategies(c)
103
Unfavorable results, primarily in the power full requirements strategy(13)
 90
Increase in Non-utility Margin$177

(a)Natural gas structured transactions typically involve a physical purchase or sale of natural gas in the future and/or natural gas basis financial instruments which are derivatives and a related non-derivative pipeline transportation contract. These gas structured transactions can result in significant earnings volatility as the derivative components are marked-to-market without revaluing the related non-derivative contracts.
(b)Amount includes $113 million of timing related gains related to gas strategies which will reverse in future periods as the underlying contracts settle.
(c)Amount includes $95 million of timing related losses related to gas strategies recognized in previous periods that reversed as the underlying contracts settled.
Other (Income) and Deductions increased$1 million in 2018 and decreased $27 million in 2017 due to contributions to the DTE Energy Foundation in 2016.
Outlook — In the near-term, Energy Trading expects market conditions to remain challenging, and the profitability of this segment may be impacted by the volatility in commodity prices and the uncertainty of impacts associated with regulatory changes, and changes in operating rules of RTOs. Significant portions of the Energy Trading portfolio are economically hedged. Most financial instruments and physical power and natural gas contracts are deemed derivatives, whereas natural gas inventory, pipeline transportation, renewable energy credits, and storage assets are not derivatives. As a result, Energy Trading will experience earnings volatility as derivatives are marked-to-market without revaluing the underlying non-derivative contracts and assets. Energy Trading's strategy is to economically manage the price risk of these underlying non-derivative contracts and assets with futures, forwards, swaps, and options. This results in gains and losses that are recognized in different interim and annual accounting periods.
See also the "Fair Value" section herein and Notes 12 and 13 to the Consolidated Financial Statements in Item 8 of this Report, "Fair Value" and "Financial and Other Derivative Instruments," respectively.


EMPLOYEES
DTE Energy and its subsidiaries had approximately 10,00010,600 employees as of December 31, 2015,2018, of which approximately 4,9005,200 were represented by unions. DTE Electric had approximately 4,5004,900 employees as of December 31, 2015,2018, of which approximately 2,6002,800 were represented by unions. There are several bargaining units for DTE Energy’sEnergy subsidiaries' represented employees. The majority of represented employees for both DTE Energy and DTE Electric are under contracts that expire in 20162020 and 2017.2021.


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Item 1A.Risk Factors
There are various risks associated with the operations of the Registrants' utility businesses and DTE Energy's non-utility businesses. To provide a framework to understand the operating environment of the Registrants, below is a brief explanation of the more significant risks associated with their businesses. Although the Registrants have tried to identify and discuss key risk factors, others could emerge in the future. Each of the following risks could affect performance.
The Registrants are subject to rate regulation.Electric and gas rates for the utilities are set by the MPSC and the FERC and cannot be changed without regulatory authorization. The Registrants may be negatively impacted by new regulations or interpretations by the MPSC, the FERC, or other regulatory bodies. The Registrants' ability to recover costs may be impacted by the time lag between the incurrence of costs and the recovery of the costs in customers' rates. Regulators also may decide to disallow recovery of certain costs in customers' rates if they determine that those costs do not meet the standards for recovery under current governing laws and regulations. The Registrants' utilities typically self-implement base rate changes six months after rate case filings, in accordance with Michigan law. However, if the final rates authorized by regulators in the final rate order are lower than the amounts the Registrants collected during the self-implementation period, the Registrants must refund the difference with interest. Regulators may also disagree with the Registrants' rate calculations under the various mechanisms that are intended to mitigate the risk to their utilities related to certain aspects of the business. If the Registrants cannot agree with regulators on an appropriate reconciliation of those mechanisms, it may impact the Registrants' ability to recover certain costs through customer rates. Regulators may also decide to eliminate these mechanisms in future rate cases, which may make it more difficult for the Registrants to recover their costs in the rates charged to customers. The Registrants cannot predict what rates the MPSC will authorize in future rate cases. New legislation, regulations, or interpretations could change how the business operates, impact the Registrants' ability to recover costs through rates or the timing of such recovery, or require the Registrants to incur additional expenses. The outcome of the current Michigan energy policy reform legislative process could impact the Registrants' recovery of costs through rates.
Changes to Michigan's electric retail access program could negatively impact the Registrants' financial performance. The State of Michigan currently experiences a hybrid market, where the MPSC continues to regulate electric rates for DTE Electric customers, while alternative electric suppliers charge market-based rates. MPSC rate orders, and energy legislation enacted by the State of Michigan, in 2008, have placed a 10% cap on the total potential retail access migration. However, even with the legislated 10% cap on participation, there continues to be legislative and financial risk associated with the electric retail access program. Electric retail access migration is sensitive to market price and full service electric price changes. The Registrants are required under current regulation to provide full service to retail access customers that choose to return, potentially resulting in the need for additional generating capacity.


The outcomeRegistrants' electric distribution system and DTE Energy's gas distribution system are subject to risks from their operation, which could reduce revenues, increase expenses, and have a material adverse effect on their business, financial position, and results of operations. The Registrants' electric distribution and DTE Energy’s gas distribution systems are subject to many operational risks. These operational systems and infrastructure have been in service for many years. Equipment, even when maintained in accordance with good utility practices, is subject to operational failure, including events that are beyond the Registrants' control, and could require significant operation and maintenance expense or capital expenditures to operate efficiently. Because the Registrants’ distribution systems are interconnected with those of third parties, the operation of the current Michigan energy policy reform legislative processRegistrants’ systems could impactbe adversely affected by unexpected or uncontrollable events occurring on the Registrants' recoverysystems of costs through rates.such third parties.
The MISO regional energy market, including the StateDTE Energy's non-utility businesses may not perform to its expectations. DTE Energy relies on non-utility operations for an increasing portion of Michigan, is expected to face capacity constraints beginning in 2016, due primarily to the retirement of coal-fired generation caused by increasingly stringent environmental requirements. Significant investment in new natural gas-fired generationearnings. If DTE Energy's current and renewables will be required. Under the current regulatory structure, retail access customerscontemplated non-utility investments do not fund capacity costs, potentially impactingperform at expected levels, DTE Energy could experience diminished earnings and a corresponding decline in shareholder value.
DTE Energy relies on cash flows from subsidiaries. DTE Energy is a holding company. Cash flows from the utility and non-utility subsidiaries are required to pay interest expenses and dividends on DTE Energy debt and securities. Should a major subsidiary not be able to pay dividends or transfer cash flows to DTE Energy, its ability to pay interest and dividends would be restricted.
The Registrants' businesses have safety risks. The Registrants' electric supply reliabilitydistribution system, power plants, renewable energy equipment, and utility customer affordability.other facilities, and DTE Energy's gas distribution system, gas infrastructure, and other facilities, could be involved in incidents that result in injury, death, or property loss to employees, customers, third parties, or the public. Although the Registrants have insurance coverage for many potential incidents, depending upon the nature and severity of any incident, they could experience financial loss, damage to their reputation, and negative consequences from regulatory agencies or other public authorities.
Environmental laws and liability may be costly. The Registrants are subject to, and affected by, numerous environmental regulations. These regulations govern air emissions, water quality, wastewater discharge, and disposal of solid and hazardous waste. Compliance with these regulations can significantly increase capital spending, operating expenses, and plant down times, and can negatively affect the affordability of the rates charged to customers.
Uncertainty around future environmental regulations creates difficulty planning long-term capital projects in the Registrants' generation fleet and, for DTE Energy,Energy's gas distribution businesses. These laws and regulations require the Registrants to seek a variety of environmental licenses, permits, inspections, and other regulatory approvals. The Registrants could be required to install expensive pollution control measures or limit or cease activities, including the retirement of certain generating plants, based on these regulations. Additionally, the Registrants may become a responsible party for environmental cleanup at sites identified by a regulatory body. The Registrants cannot predict with certainty the amount and timing of future expenditures related to environmental matters because of the difficulty of estimating cleanup costs. There is also uncertainty in quantifying liabilities under environmental laws that impose joint and several liability on potentially responsible parties.

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The Registrants may also incur liabilities as a result of potential future requirements to address climate change issues. Proposals for voluntary initiatives and mandatory controls are being discussed both in the United States and worldwide to reduce GHGs such as carbon dioxide, a by-product of burning fossil fuels. If increased regulations of GHG emissions are implemented, the operations of DTE Electric's fossil-fueled generation assets may be significantly impacted. Since there can be no assurances that environmental costs may be recovered through the regulatory process, the Registrants' financial performance may be negatively impacted as a result of environmental matters.
For DTE Energy, future environmental regulation of natural gas extraction techniques, including hydraulic fracturing, being discussed both at the United States federal level and by some states may affect the profitability of natural gas extraction businesses which could affect demand for, and profitability of, DTE Energy's gas transportation businesses.
Threats of cyber incidents, physical security, and terrorism could affect the Registrants' business. Issues may threaten the Registrants such as cyber incidents, physical security, or terrorism that may disrupt the Registrants' operations, and could harm the Registrants' operating results.


Information security risks have increased in recent years as a result of the proliferation of new technologies and the increased sophistication and frequency of cyberattacks, and data security breaches. The Registrants' industry requires the continued operation of sophisticated information and control technology systems and network infrastructure. Despite implementation of security measures, all of the Registrants' technology systems are vulnerable to disability or failures due to cyber incidents, physical security threats, acts of war or terrorism, and other causes, as well as loss of operational control of the Registrants' electric generation and distribution assets and, DTE Energy's gas distribution assets. If the Registrants' information technology systems were to fail and they were unable to recover in a timely way, the Registrants may be unable to fulfill critical business functions, which could have a material adverse effect on the Registrants' business, operating results, and financial condition.
Suppliers, vendors, contractors, and information technology providers have access to systems that support the Registrants’ operations and maintain customer and employee data.  A breach of these third-party systems could adversely affect the business as if it was a breach of our own system.  Also, because the Registrants’ generation and distribution systems are part of an interconnected system, a disruption caused by a cyber incident at another utility, electric generator, system operator, or commodity supplier could also adversely affect the Registrants’ businesses, operating results, and financial condition.
In addition, the Registrants' generation plants and electrical distribution facilities, and DTE Energy's gas pipeline and storage facilities, in particular, may be targets of physical security threats or terrorist activities that could disrupt the Registrants' ability to produce or distribute some portion of their products. The Registrants have increased security as a result of past events and may be required by regulators or by the future threat environment to make investments in security that the Registrants cannot currently predict.
Failure to maintain the security of personally identifiable information could adversely affect the Registrants. In connection with the Registrants' businesses, they collect and retain personally identifiable information of their customers, shareholders, and employees. Customers, shareholders, and employees expect that the Registrants will adequately protect their personal information. The regulatory environment surrounding information security and privacy is increasingly demanding. A significant theft, loss, or fraudulent use of customer, shareholder, employee, or Registrant data by cybercrime or otherwise, could adversely impact the Registrants' reputation, and could result in significant costs, fines, and litigation.
Construction and capital improvements to the Registrants' power facilities, DTE Energy's distribution systems and its Gas Storage and Pipelines business subject them to risk. The Registrants are managing ongoing, and planning future, significant construction and capital improvement projects at the Registrants' multiple power generation and distribution facilities, at DTE Energy's gas distribution system, and at DTE Energy's Gas Storage and Pipelines business. Many factors that could cause delays or increased prices for these complex projects are beyond the Registrants' control, including the cost of materials and labor, subcontractor performance, timing and issuance of necessary permits or approvals (including required certificates from regulatory agencies), construction disputes, impediments to acquiring rights-of-way or land rights on a timely basis and on acceptable terms, cost overruns, and weather conditions. Failure to complete these projects on schedule and on budget for any reason could adversely affect the Registrants' financial performance, operations, or expected investment returns at the affected facilities, businesses and development projects.
Operation of a nuclear facility subjects the Registrants to risk. Ownership of an operating nuclear generating plant subjects the Registrants to significant additional risks. These risks include, among others, plant security, environmental regulation and remediation, changes in federal nuclear regulation, increased capital expenditures to meet industry requirements, and operational factors that can significantly impact the performance and cost of operating a nuclear facility. Whilefacility compared to other generation options. Insurance maintained by the Registrants maintain insurance for various nuclear-related risks there can be no assurances that such insurance willmay not be sufficient to cover the Registrants' costs in the event of an accident or business interruption at the nuclear generating plant, which may affect the Registrants' financial performance. In addition, while the Registrants have aRegistrants' nuclear decommissioning trust fund, to finance the decommissioning of the nuclear generating plant, there can be no assurances that such fund willmay not be sufficient to fund the cost of decommissioning. A decline in market value of assets held in decommissioning trust funds due to poor investment performance or other factors may increase the funding requirements for these obligations. Any increase in funding requirements may have a material impact on the Registrants’ liquidity, financial position, or results of operations.


The supply and/or price of energy commodities and/or related services may impact the Registrants' financial results.The Registrants are dependent on coal for much of their electrical generating capacity.capacity as well as uranium for their nuclear operations. DTE Energy's access to natural gas supplies is critical to ensure reliability of service for utility gas customers. DTE Energy's non-utility businesses are also dependent upon supplies and prices of energy commodities and services. Price fluctuations, fuel supply disruptions, and changes in transportation costs, could have a negative impact on the amounts DTE Electric charges utility customers for electricity and DTE Gas charges utility customers for gas, and on the profitability of DTE Energy's non-utility businesses. The Registrants haveRegistrants' hedging strategies and regulatory recovery mechanisms in placemay be insufficient to mitigate some of the negative fluctuations in commodity supply prices in their utility and, for DTE Energy, non-utility businesses, but there can be no assurances thatand the Registrants' financial performance will notmay therefore be negatively impacted by price fluctuations. The price of energy also impacts the market for DTE Energy's non-utility businesses that compete with utilities and alternative electric suppliers.
The supply and/or price of other industrial raw and finished inputs and/or related services may impact the Registrants' financial results. The Registrants are dependent on supplies of certain commodities, such as copper and limestone, among others, and industrial materials, and services in order to maintain day-to-day operations and maintenance of their facilities. Price fluctuations, or supply interruptions for these commodities and other items, could have a negative impact on the amounts charged to customers for the Registrants' utility products and, for DTE Energy, on the profitability of the non-utility businesses.
Emerging technologies may have a material adverse effect on the Registrants. Advances in technology that produce power or reduce power consumption include cost-effective renewable energy technologies, distributed generation, energy waste reduction technologies, and energy storage devices. Such developments may impact the price of energy, may affect energy deliveries as customer-owned generation becomes more cost-effective, may require further improvements to our distribution systems to address changing load demands, and could make portions of our electric system power supply and/or distribution facilities obsolete prior to the end of their useful lives. Such technologies could also result in further declines in commodity prices or demand for delivered energy. Each of these factors could materially affect the Registrants’ results of operations, cash flows, or financial position.
Adverse changes in the Registrants' credit ratings may negatively affect them. Regional and national economic conditions, increased scrutiny of the energy industry and regulatory changes, as well as changes in the Registrants' economic performance, could result in credit agencies reexamining their credit ratings. While credit ratings reflect the opinions of the credit agencies issuing such ratings and may not necessarily reflect actual performance, a downgrade in the Registrants' credit ratings below investment grade could restrict or discontinue their ability to access capital markets and could result in an increase in their borrowing costs, a reduced level of capital expenditures, and could impact future earnings and cash flows. In addition, a reduction in the Registrants' credit ratings may require them to post collateral related to various physical or financially settled contracts for the purchase of energy-related commodities, products, and services, which could impact their liquidity.

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Poor investment performance of pension and other postretirement benefit plan assets and other factors impacting benefit plan costs could unfavorably impact the Registrants' liquidity and results of operations.The Registrants' costs of providing non-contributory defined benefit pension plans and other postretirement benefit plans are dependent upon a number of factors, such as the rates of return on plan assets, the level of interest rates used to measure the required minimum funding levels of the plans, future government regulation, and the Registrants' required or voluntary contributions made to the plans. The performance of the debt and equity markets affects the value of assets that are held in trust to satisfy future obligations under the Registrants' plans. The Registrants have significant benefit obligations and hold significant assets in trust to satisfy these obligations. These assets are subject to market fluctuations and will yield uncertain returns, which may fall below the Registrants' projected return rates. A decline in the market value of the pension and other postretirement benefit plan assets will increase the funding requirements under the pension and other postretirement benefit plans if the actual asset returns do not recover these declines in the foreseeable future. Additionally, the pension and other postretirement benefit plan liabilities are sensitive to changes in interest rates. AsIf interest rates decrease, the liabilities increase, resulting in increasing benefit expense and funding requirements. Also, if future increases in pension and other postretirement benefit costs as a result of reduced plan assets are not recoverable from the Registrants' utility customers, the results of operations and financial position of the Registrants could be negatively affected. Without sustained growth in the plan investments over time to increase the value of plan assets, the Registrants could be required to fund these plans with significant amounts of cash. Such cash funding obligations could have a material impact on the Registrants' cash flows, financial position, or results of operations.


The Registrants' ability to access capital markets is important.The Registrants' ability to access capital markets is important to operate their businesses and to fund capital investments. Turmoil in credit markets may constrain the Registrants' ability, as well as the ability of their subsidiaries, to issue new debt, including commercial paper, and refinance existing debt at reasonable interest rates. In addition, the level of borrowing by other energy companies, and the market as a whole, could limit the Registrants' access to capital markets. The Registrants' long-term revolving credit facilities do not expire until 2020,2022, but the Registrants regularly access capital markets to refinance existing debt or fund new projects at the Registrants' utilities and DTE Energy's non-utility businesses, and the Registrants cannot predict the pricing or demand for those future transactions.
Construction and capital improvements to the Registrants' power facilities and DTE Energy's distribution systems subject them to risk. The Registrants are managing ongoing, and planning future, significant construction and capital improvement projects at multiple power generation and distribution facilities and DTE Energy's gas distribution system. Many factors that could cause delays or increased prices for these complex projects are beyond the Registrants' control, including the cost of materials and labor, subcontractor performance, timing and issuance of necessary permits, construction disputes, and weather conditions. Failure to complete these projects on schedule and on budget for any reason could adversely affect the Registrants' financial performance and operations at the affected facilities and businesses.
DTE Energy's non-utility businesses may not perform to its expectations. DTE Energy relies on non-utility operations for an increasing portion of earnings. If DTE Energy's current and contemplated non-utility investments do not perform at expected levels, DTE Energy could experience diminished earnings and a corresponding decline in shareholder value.
DTE Energy's participation in energy trading markets subjects it to risk.Events in the energy trading industry have increased the level of scrutiny on the energy trading business and the energy industry as a whole. In certain situations, DTE Energy may be required to post collateral to support trading operations, which could be substantial. If access to liquidity to support trading activities is curtailed, DTE Energy could experience decreased earnings potential and cash flows. Energy trading activities take place in volatile markets and expose DTE Energy to risks related to commodity price movements, deviations in weather, and other related risks. DTE Energy's trading business routinely has speculative trading positions in the market, within strict policy guidelines DTE Energy sets, resulting from the management of DTE Energy's business portfolio. To the extent speculative trading positions exist, fluctuating commodity prices can improve or diminish DTE Energy's financial results and financial position. DTE Energy manages its exposure by establishing and enforcing strict risk limits and risk management procedures. During periods of extreme volatility, these risk limits and risk management procedures may not work as planned and cannot eliminate all risks associated with these activities.
DTE Energy's ability to utilize production tax credits may be limited.  To reduce U.S. dependence on imported oil, the Internal Revenue Code provides production tax credits as an incentive for taxpayers to produce fuels and electricity from alternative sources. DTE Energy generated production tax credits from coke production, landfill gas recovery, reduced emission fuel, renewable energy generation, and gas production operations. All production tax credits taken after 2013 are subject to audit by the IRS. If DTE Energy's production tax credits were disallowed in whole or in part as a result of an IRS audit, there could be additional tax liabilities owed for previously recognized tax credits that could significantly impact DTE Energy's earnings and cash flows.

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Weather significantly affects operations.At both utilities, deviations from normal hot and cold weather conditions affect the Registrants' earnings and cash flows. Mild temperatures can result in decreased utilization of the Registrants' assets, lowering income and cash flows. At DTE Electric, ice storms, tornadoes, or high winds can damage the electric distribution system infrastructure and power generation facilities and require it to perform emergency repairs and incur material unplanned expenses. The expenses of storm restoration efforts may not be fully recoverable through the regulatory process. DTE Gas can experience higher than anticipated expenses from emergency repairs on its gas distribution infrastructure required as a result of weather related issues.
Unplanned power plant outages may be costly. Unforeseen maintenance may be required to safely produce electricity or comply with environmental regulations. As a result of unforeseen maintenance, the Registrants may be required to make spot market purchases of electricity that exceed the costs of generation. The Registrants' financial performance may be negatively affected if unable to recover such increased costs.
DTE Energy relies on cash flows from subsidiaries.  DTE Energy is a holding company. Cash flows from the utility and non-utility subsidiaries are required to pay interest expenses and dividends on DTE Energy debt and securities. Should a major subsidiary not be able to pay dividends or transfer cash flows to DTE Energy, its ability to pay interest and dividends would be restricted.
Renewable portfolio standards and energy efficiency programs may affect the Registrants' business.  The Registrants are subject to existing Michigan, and potential future, federal legislation and regulation requiring them to secure sources of renewable energy. The Registrants have complied with the existing state legislation, but do not know what requirements may be added by federal legislation. In addition, there could be additional state requirements increasing the percentage of power required to be provided by renewable energy sources. The Registrants cannot predict the financial impact or costs associated with complying with potential future legislation and regulations. Compliance with these requirements can significantly increase capital expenditures and operating expenses and can negatively affect the affordability of the rates charged to customers.
The Registrants are also required by Michigan legislation to implement energy efficiency measures and provide energy efficiency customer awareness and education programs. These requirements necessitate expenditures, and implementation of these programs creates the risk of reducing the Registrants' revenues as customers decrease their energy usage. The Registrants cannot predict how these programs will impact their business and future operating results.
Regional, national, and international economic conditions can have an unfavorable impact on the Registrants. The Registrants' utility and DTE Energy's non-utility businesses follow the economic cycles of the customers they serve and credit risk of counterparties they do business with. Should the financial conditions of some of DTE Energy's significant customers deteriorate as a result of regional, national or international economic conditions, reduced volumes of electricity and gas, and demand for energy services DTE Energy supplies, collections of accounts receivable, reductions in federal and state energy assistance funding, and potentially higher levels of lost gas or stolen gas and electricity could result in decreased earnings and cash flows.
Threats of terrorism or cyber-attacks couldRenewable portfolio standards and energy waste reduction programs may affect the Registrants' business.The Registrants are subject to existing Michigan, and potential future, federal legislation and regulation requiring them to secure sources of renewable energy. The Registrants have complied with the existing federal and state legislation, but do not know what requirements may be threatenedadded by problems such as computer virusesfederal or terrorism that may disruptstate legislation in the Registrants' operations and could harm the Registrants' operating results. The Registrants' industry requires the continued operation of sophisticated information technology systems and network infrastructure. Despite implementation of security measures, all of the Registrants' technology systems are vulnerable to disability or failures due to hacking, viruses, acts of war or terrorism, and other causes. If the Registrants' information technology systems were to fail and they were unable to recover in a timely way, the Registrants might be unable to fulfill critical business functions, which could have a material adverse effect on the Registrants' business, operating results, and financial condition.
future. In addition, the Registrants' generation plantsRegistrants expect to comply with new Michigan legislation increasing the percentage of power required to be provided by renewable energy sources. The Registrants cannot predict the financial impact or costs associated with complying with potential future legislation and electrical distribution facilitiesregulations. Compliance with these requirements can significantly increase capital expenditures and for DTE Energy, gas pipelineoperating expenses and storage facilities, in particular may be targetscan negatively affect the affordability of terrorist activities that could disruptthe rates charged to customers.
The Registrants are also required by Michigan legislation to implement energy waste reduction measures and provide energy waste reduction customer awareness and education programs. These requirements necessitate expenditures, and implementation of these programs creates the risk of reducing the Registrants' ability to produce or distribute some portion ofrevenues as customers decrease their products.energy usage. The Registrants have increased security as a result of past eventscannot predict how these programs will impact their business and may be required by regulators or by the future terrorist threat environment to make investments in security that the Registrants cannot currently predict.operating results.

21



Failure to maintain the security of personally identifiable information could adversely affect the Registrants.  In connection with the Registrant's businesses, they collect and retain personally identifiable information of their customers, shareholders, and employees. Customers, shareholders, and employees expect that the Registrants will adequately protect their personal information, and the regulatory environment surrounding information security and privacy is increasingly demanding. A significant theft, loss, or fraudulent use of customer, shareholder, employee, or Registrant data by cybercrime or otherwise could adversely impact the Registrants' reputation and could result in significant costs, fines, and litigation.
Failure to attract and retain key executive officers and other skilled professional and technical employees could have an adverse effect on the Registrants' operations.Registrants operations. The Registrants' businesses are dependent on their ability to attract and retain skilled employees. Competition for skilled employees in some areas is high, and the inability to attract and retain these employees could adversely affect the Registrants' business and future operating results. In addition, the Registrants have an aging utility workforce, and the failure of a successful transfer of knowledge and expertise could negatively impact their operations.
A work interruption may adversely affect the Registrants. There are several bargaining units for DTE Energy's approximately 4,9005,200 and DTE Electric's approximately 2,6002,800 represented employees. The majority of represented employees are under contracts that expire in 20162020 and 2017.2021. A union choosing to strike would have an impact on the Registrants' businesses. The Registrants are unable to predict the effect a work stoppage would have on their costs of operations and financial performance.
DTE Energy's ability to utilize production tax credits may be limited. To reduce U.S. dependence on imported oil, the Internal Revenue Code provides production tax credits as an incentive for taxpayers to produce fuels and electricity from alternative sources. DTE Energy generated production tax credits from coke production, renewable gas recovery, reduced emission fuel, and gas production operations, and for the Registrants, renewable energy generation. If the Registrants' production tax credits were disallowed in whole or in part as a result of an IRS audit or changes in tax law, there could be additional tax liabilities owed for previously recognized tax credits that could significantly impact the Registrants' earnings and cash flows.
If DTE Energy's goodwill becomes impaired, it may be required to record a charge to earnings. DTE Energy annually reviews the carrying value of goodwill associated with acquisitions it has made for impairment. Factors that may be considered for purposes of this analysis include any change in circumstances indicating that the carrying value of DTE Energy goodwill may not be recoverable, such as a decline in stock price and market capitalization, future cash flows, and slower growth rates in the industry. DTE Energy cannot predict the timing, strength, or duration of any economic slowdown or subsequent recovery, worldwide or in the economy or markets in which it operates; however, when events or changes in circumstances indicate that the carrying value of these assets may not be recoverable, DTE Energy may take a non-cash impairment charge, which could potentially materially impact DTE Energy's results of operations and financial position.
The Registrants' businesses have safety risks. The Registrants' electric distribution system, power plants, wind energy equipment, and other facilities, and DTE Energy's gas distribution system, gas infrastructure, and other facilities, could be involved in incidents that result in injury, death or property loss to employees, customers, or the public. Although the Registrants have insurance coverage for many potential incidents, depending upon the nature and severity of any incident, they could experience financial loss, damage to their reputation, and negative consequences from regulatory agencies or other public authorities.
The Registrants may not be fully covered by insurance. The Registrants have a comprehensive insurance program in place to provide coverage for various types of risks, including catastrophic damage as a result of acts of God,severe weather or other natural disasters, war, terrorism, or a combination of other significant unforeseen events that could impact the Registrants' operations. Economic losses might not be covered in full by insurance, or the Registrants' insurers may be unable to meet contractual obligations.obligations.

Item 1B. Unresolved Staff Comments
None.



Item 3. Legal Proceedings
In March 2018, the Trenton Channel Power Plant experienced exceedances of its mercury emission limits. The exceedances were reported to the EPA and the MDEQ. On September 12, 2018, the EPA issued a NOV. DTE Electric is currently working with the EPA to address the NOV.  At this time, DTE Electric cannot predict the impact of the NOV.
For more information on material legal proceedings and matters related to the Registrants, see Notes 89 and 1718 to the Consolidated Financial Statements in Item 8 of this Report, "Regulatory Matters" and "Commitments and Contingencies".Contingencies," respectively.

Item 4. Mine Safety Disclosures
Not applicable.

22




Part II
Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters, and Issuer Purchases of Equity Securities
DTE Energy common stock is listed under the ticker symbol "DTE" on the New York Stock Exchange, which is the principal market for such stock. The following table indicates the reported high and low sales prices of DTE Energy common stock on the Composite Tape of the New York Stock Exchange and dividends paid per share for each quarterly period during the past two years:
        Dividends
Paid per Share
Year Quarter High Low 
2015    
  
  
  First $92.27
 $76.84
 $0.6900
  Second $84.27
 $73.23
 $0.6900
  Third $85.12
 $74.53
 $0.7300
  Fourth $85.36
 $77.35
 $0.7300
2014    
  
  
  First $74.61
 $64.84
 $0.6550
  Second $79.45
 $72.76
 $0.6550
  Third $78.89
 $71.60
 $0.6900
  Fourth $90.77
 $75.76
 $0.6900
At December 31, 2015,2018, there were 179,470,213181,925,281 shares of DTE Energy common stock outstanding. These shares were held by a total of 58,99951,338 shareholders of record.
DTE Energy paid cash dividends on common stock of $501 million in 2015, $470 million in 2014, and $445 million in 2013. The amount of future dividends will depend on DTE Energy's earnings, cash flows, financial condition, and other factors that are periodically reviewed by the DTE Energy Board of Directors. Although there can be no assurances, DTE Energy anticipates paying dividends for the foreseeable future.
All of the 138,632,324138,632,234 issued and outstanding shares of DTE Electric common stock, par value $10 per share, are owned by DTE Energy, and constitute 100% of the voting securities of DTE Electric. Therefore, no market exists for DTE Electric's common stock.
DTE Electric paid cash dividends on common stock of $395 million in 2015, $370 million in 2014, and $342 million in 2013.
For information on DTE Energy dividend restrictions, see Note 1516 to the Consolidated Financial Statements in Item 8 of this Report, "Short-Term Credit Arrangements and Borrowings".Borrowings."
All of DTE Energy's equity compensation plans that provide for the annual awarding of stock-based compensation have been approved by shareholders. For additional detail, see Note 1921 to the Consolidated Financial Statements in Item 8 of this Report, "Stock-Based Compensation".Compensation."
See the following table for information as of December 31, 2015:2018:
 Number of Securities to be Issued Upon Exercise of Outstanding Options Weighted-Average Exercise Price of Outstanding Options Number of Securities Remaining Available for Future Issuance Under Equity Compensation Plans
Plans approved by shareholders262,282
 $42.52
 2,892,454
 Number of Securities to be Issued Upon Exercise of Outstanding Options Weighted-Average Exercise Price of Outstanding Options Number of Securities Remaining Available for Future Issuance Under Equity Compensation Plans
Plans approved by shareholders52,100
 $43.30
 2,897,674

23



UNREGISTERED SALES OF DTE ENERGY EQUITY SECURITIES AND USE OF PROCEEDS
Purchases of DTE Energy Equity Securities by the Issuer and Affiliated Purchasers
The following table provides information about DTE Energy's purchases of equity securities that are registered by DTE Energy pursuant to Section 12 of the Exchange Act of 1934 for the quarter ended December 31, 2015:2018:
 Number of Shares Purchased (a) Average Price
Paid per Share (a)
 Number of Shares Purchased as Part of Publicly Announced
Plans or Programs
 Average Price Paid per Share Maximum Dollar
Value that May
Yet Be Purchased Under the Plans or Programs
10/01/2015 — 10/31/20151,576
 $79.43
 
 
 
11/01/2015 — 11/30/20152,436
 $78.53
 
 
 
12/01/2015 — 12/31/20151,900
 $78.42
 
 
 
Total5,912
  
 
  
  
 
Number of Shares Purchased(a)
 
Average Price
Paid per Share
(a)
 Number of Shares Purchased as Part of Publicly Announced
Plans or Programs
 Average Price Paid per Share Maximum Dollar
Value that May
Yet Be Purchased Under the Plans or Programs
10/01/2018 — 10/31/2018143
 $110.14
 
 
 
11/01/2018 — 11/30/2018
 $
 
 
 
12/01/2018 — 12/31/2018
 $
 
 
 
Total143
  
 
  
  

(a)Represents shares of DTE Energy common stock withheld to satisfy income tax obligations upon the vesting of restricted stock based on the price in effect at the grant date.


COMPARISON OF CUMULATIVE FIVE YEAR TOTAL RETURN
Total Return to DTE Energy Shareholders
(Includes reinvestment of dividends)
 Annual Return Percentage
Year Ended December 31,
 Annual Return Percentage
Year Ended December 31,
Company/Index 2011 2012 2013 2014 2015 2014 2015 2016 2017 2018
DTE Energy Company 25.76
 14.90
 14.89
 34.61
 (3.77) 34.61
 (3.77) 26.93
 14.59
 4.19
S&P 500 Index 2.11
 16.00
 32.39
 13.69
 1.38
 13.69
 1.38
 11.95
 21.82
 (4.39)
S&P 500 Multi-Utilities Index 18.41
 4.24
 17.88
 28.94
 (1.73) 28.94
 (1.73) 18.56
 12.09
 1.77
 Indexed Returns
Year Ended December 31,
 Indexed Returns
Year Ended December 31,
 Base Period           Base Period          
Company/Index 2010 2011 2012 2013 2014 2015 2013 2014 2015 2016 2017 2018
DTE Energy Company 100
 125.76
 144.51
 166.03
 223.49
 215.07
 100.00
 134.61
 129.54
 164.41
 188.40
 196.30
S&P 500 Index 100
 102.11
 118.45
 156.82
 178.29
 180.75
 100.00
 113.69
 115.26
 129.04
 157.19
 150.29
S&P 500 Multi-Utilities Index 100
 118.41
 123.42
 145.50
 187.59
 184.35
 100.00
 128.94
 126.71
 150.22
 168.38
 171.35

24



dteenergy20_chart-06124a04.jpg


25




Item 6. Selected Financial Data
The following selected financial data of DTE Energy should be read in conjunction with the accompanying Management’s Discussion and Analysis in Item 7 of this Report and Combined Notes to Consolidated Financial Statements in Item 8 of this Report. This information has been omitted for DTE Electric per General Instruction I (2) (a) of Form 10-K for wholly-owned subsidiaries (reduced disclosure format).
2015 2014 2013 2012 20112018 2017 2016 2015 2014
(In millions, except per share amounts)(In millions, except per share amounts)
Operating Revenues$10,337
 $12,301
 $9,661
 $8,791
 $8,858
$14,212
 $12,607
 $10,630
 $10,337
 $12,301
Net Income Attributable to DTE Energy Company(a)         $1,120
 $1,134
 $868
 $727
 $905
Income from continuing operations attributable to DTE Energy Company (a)$727
 $905
 $661
 $666
 $714
Discontinued operations (b)
 
 
 (56) (3)
Net Income Attributable to DTE Energy Company$727
 $905
 $661
 $610
 $711
Diluted Earnings Per Common Share         
Income from continuing operations$4.05
 $5.10
 $3.76
 $3.88
 $4.20
Discontinued operations
 
 
 (0.33) (0.02)
Diluted Earnings Per Common Share$4.05
 $5.10
 $3.76
 $3.55
 $4.18
$6.17
 $6.32
 $4.83
 $4.05
 $5.10
Financial Information                  
Dividends declared per share of common stock$2.84
 $2.69
 $2.59
 $2.42
 $2.32
$3.60
 $3.36
 $3.06
 $2.84
 $2.69
Total assets$28,737
 $27,899
 $25,935
 $26,318
 $25,958
Long-term debt, including capital leases$8,835
 $8,343
 $7,214
 $7,014
 $7,187
Total Assets$36,288
 $33,767
 $32,041
 $28,662
 $27,827
Long-Term Debt(b)
$12,134
 $12,185
 $11,269
 $8,760
 $8,271
Shareholders’ equity$8,772
 $8,327
 $7,921
 $7,373
 $7,009
$10,237
 $9,512
 $9,011
 $8,772
 $8,327

(a)2011The 2017 results include an $87a $105 million net income tax benefit related to the enactment of the MCIT.TCJA.
(b)Discontinued operations represents DTE Energy's Unconventional Gas Production business that was sold in 2012 resulting in a $55 million after-tax loss on sale.Long-Term Debt includes Capital lease obligations and excludes debt due within one year.

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations
The following combined discussion is separately filed by DTE Energy and DTE Electric. However, DTE Electric does not make any representations as to information related solely to DTE Energy or the subsidiaries of DTE Energy other than itself.
EXECUTIVE OVERVIEW
DTE Energy is a diversified energy company with 2015 operating revenues2018 Operating Revenues of approximately $10.3$14.2 billion and assetsTotal Assets of approximately $28.7$36.3 billion. DTE Energy is the parent company of DTE Electric and DTE Gas, regulated electric and natural gas utilities engaged primarily in the business of providing electricity and natural gas sales, distribution, and storage services throughout Michigan. DTE Energy operates three energy-related non-utility segments with operations throughout the United States.
The following table summarizes DTE Energy's financial results:
Years Ended December 31,Years Ended December 31,
2015 2014 20132018 2017 2016
(In millions, except per share amounts)(In millions, except per share amounts)
Net Income Attributable to DTE Energy Company$727
 $905
 $661
$1,120
 $1,134
 $868
Diluted Earnings per Common Share$4.05
 $5.10
 $3.76
$6.17
 $6.32
 $4.83
The decrease in 20152018 Net Income Attributable to DTE Energy Company iswas primarily due to lower earnings in the Gas Storage and Pipelines, Energy Trading, and Corporate and Other segments, partially offset by higher earnings in the Electric, Gas, and Power and Industrial Projects segments. The 2018 decrease was partially attributable to true-up adjustments for the remeasurement of deferred taxes of $21 million as the adjustments increased Income Tax Expense, of which $17 million was attributable to the regulated utilities and increased Regulatory liabilities. The increase in 2017 Net Income Attributable to DTE Energy Company was primarily due to higher earnings in the Gas Storage and Pipelines, Energy Trading, and Power and Industrial Projects segments. The increase in 2014 Net Income Attributable to DTE Energy Company is primarily due to highersegments, partially offset by lower earnings in the Energy Trading, Electric, PowerCorporate and Industrial Projects, and Gas Storage and Pipelines segments.Other segment. The 2017 increase was also due to $105 million of net income tax benefit related to the enactment of the TCJA.

26



Please see detailed explanations of segment performance in the following Results"Results of OperationsOperations" section.
DTE Energy's strategy is to achieve long-term earnings growth, a strong balance sheet, and an attractive dividend yield.


DTE Energy's utilities are investing capital to improve customer reliability through investments in base infrastructure and new generation, and to comply with environmental requirements. DTE Energy expects that planned significant capital investments will result in earnings growth. DTE Energy is focused on executing plans to achieve operational excellence and customer satisfaction with a focus on customer affordability. DTE Energy operates in a constructive regulatory environment and has solid relationships with its regulators.
In May 2017, DTE Energy announced its plan to reduce carbon emissions. This goal will be attained by cutting carbon emissions 30% by the early 2020s, 45% by 2030, 75% by 2040, and more than 80% by 2050. To achieve this reduction, DTE Energy will transition away from coal-powered sources and incorporate more renewable energy, energy waste reduction projects, demand response, and natural gas fueled generation. DTE Energy has already begun the transition in the way it produces power through the continued retirement of its aging coal-fired plants. In May 2018, DTE Energy announced its plans to accelerate its clean energy initiatives by targeting at least a 50% clean energy goal by 2030 to be achieved through a combination of investments in renewable energy and energy waste reduction projects. Refer to the "Capital Investments" section below for further discussion.
DTE Energy has significant investments in non-utility businesses. DTE Energy employs disciplined investment criteria when assessing growth opportunities that leverage its assets, skills, and expertise, and provides diversity in earnings and geography. Specifically, DTE Energy invests in targeted energy markets with attractive competitive dynamics where meaningful scale is in alignment with its risk profile. DTE Energy expects growth opportunities in the Gas Storage and Pipelines and Power and Industrial Projects segments.
A key priority for DTE Energy is to maintain a strong balance sheet which facilitates access to capital markets and reasonably priced short-term and long-term financing. Near-term growth will be funded through internally generated cash flows and the issuance of debt and equity. DTE Energy has an enterprise risk management program that, among other things, is designed to monitor and manage exposure to earnings and cash flow volatility related to commodity price changes, interest rates, and counterparty credit risk.
CAPITAL INVESTMENTS
DTE Energy's utility businesses require significant capital investments to maintain and improve the electric generation and electric and natural gas distribution infrastructure and to comply with environmental regulations and renewable energy requirements.
DTE Electric's capital investments over the 2016-20202019-2023 period are estimated at $8.2$11.3 billion comprised of $3.8$4.0 billion for maintenancecapital replacements and other projects, $3.2$4.6 billion for distribution infrastructure, and $1.2$2.7 billion for new generation. OverDTE Electric has retired four coal-fired generation units at the next fifteen years, DTE ElectricTrenton Channel, River Rouge, and St Clair facilities and has announced plans to retire a portionits remaining thirteen coal-fired generating units. Seven of itsthese coal-fired generationgenerating units will be retired through 2023 at the Trenton Channel, River Rouge, and St. Clair facilities. The remaining coal-fired generating units at the Belle River and Monroe facilities are expected to increase the proportion of its generation mix attributable tobe retired by 2040. The retired facilities will be replaced with renewables, energy waste reduction, demand response, and natural gas-fired generation and renewables.gas fueled generation. In April 2018, DTE Electric acquired tworeceived approval from the MPSC to build a natural gas facilitiesfueled combined cycle generation facility to provide approximately 1,100 megawatts of energy beginning in 2015, as described2022. In August 2018, DTE Electric began construction on its natural gas fueled combined cycle generation facility. In March 2018, DTE Electric filed its 2018 Renewable Energy Plan with the MPSC proposing approximately 1,000 additional megawatts of energy from new wind and solar projects to be completed by 2022. The MPSC had previously approved 300 of the 1,000 additional megawatts for wind projects in Note 4an MPSC order received in September 2016. In January 2018, DTE Electric filed with the MPSC its five-year distribution operations investment and maintenance plan to the Consolidated Financial Statements in Item 8 of this Report, "Acquisitions and Exit Activities".improve system reliability. DTE Electric plans to seek regulatory approval in general rate case filings and renewable energy plan filings for capital expenditures consistent with prior ratemaking treatment. For further discussion of regulatory matters, see Note 9 to the Consolidated Financial Statements, "Regulatory Matters."
DTE Gas' capital investments over the 2016-20202019-2023 period are estimated at $1.6$2.5 billion comprised of $750 million$1.2 billion for base infrastructure, $650 millionand $1.3 billion for gas main renewal, meter move out, and pipeline integrity programs, and $200 million for expenditures related to the NEXUS Pipeline.programs. DTE Gas plans to seek regulatory approval in general rate case filings for base infrastructure capital expenditures consistent with prior ratemaking treatment. See Note 8 to the Consolidated Financial Statements in Item 8 of this Report, "Regulatory Matters" for a description of DTE Gas' IRM.
DTE Energy's non-utility businesses' capital investments are primarily for expansion, growth, and ongoing maintenance. Gas Storage and Pipelines' capital investments over the 2016-20202019-2023 period are estimated at $2.0$4.0 billion to $2.6$5.0 billion for gathering and pipeline investments and expansions, including the NEXUS Pipeline.expansions. Power and Industrial Projects' capital investments over the 2016-20202019-2023 period are estimated at $600 million$1.0 billion to $950 million$1.4 billion for investments in cogenerationindustrial energy services and on-site energyRNG projects.


ENVIRONMENTAL MATTERS
The Registrants are subject to extensive environmental regulation. Additional costs may result as the effects of various substances on the environment are studied and governmental regulations are developed and implemented. Actual costs to comply could vary substantially. The Registrants expect to continue recovering environmental costs related to utility operations through rates charged to customers.customers, as authorized by the MPSC.

27



AirDTE Electric is subject to the EPA ozone and fine particulate transport and acid rain regulations that limit power plant emissions of sulfur dioxideSO2 and nitrogen oxides.NOX. The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to additional emission controls on fossil-fueled power plants to reduce nitrogen oxide and sulfur dioxide, with further emission controls planned for reductions ofSO2, NOX, mercury, and other emissions. TheseAdditional rulemakings may occur over the next few years which could require additional controls for sulfur dioxide, nitrogen oxides,SO2, NOX, and other hazardous air pollutants over the next few years.pollutants. To comply with theseexisting requirements, DTE Electric spent approximately $2.3$2.4 billion through 2015. It is estimated that2018. DTE Electric will makedoes not anticipate additional capital expenditures of approximately $40 million in 2016.through 2025.
As directed by a June 2013 Presidential Memorandum, theThe EPA is implementinghas implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, in August 2015 the EPA finalized performance standards for emissions of carbon dioxide from new and existing electric generating units (EGUs).EGUs. In February 2016, the U.S. Supreme Court granted petitioners' requests for a stay of the carbon rules for existing EGUs (also known as the EPA Clean Power Plan) pending final review by the courts. The carbon performance standards, known asClean Power Plan has no legal effect while the stay is in place. On March 28, 2017, a presidential executive order was issued on "Promoting Energy Independence and Economic Growth." The order instructs the EPA to review, and if appropriate, suspend, revise or rescind the Clean Power Plan (CPP), require statesrule. Following the issuance of this order, the federal government requested the U.S. Court of Appeals for the D.C. Circuit to meethold all legal challenges in abeyance until the review of these regulations is completed. On October 10, 2017, the EPA proposed to rescind the Clean Power Plan and announced its intent to issue an ANPR seeking input as to whether it should replace the rule and, if so, what form it should take. In August 2018, the EPA proposed revised emission reduction targetsguidelines for GHGs from existing fossil-fueled EGUs beginning in 2022.electric utility generating units. The EPA has finalized interim standards applicable from 2022proposed rule, named the Affordable Clean Energy (ACE) rule, is intended to 2029 leading to emission standards to be achieved in 2030. States must submit initial compliance plans in September 2016, but may request an extension to submit a final compliance plan by September 2018. States that fail to submit a plan or do not meet EPA criteria for a complete plan will be subject to a federal plan that was proposed byreplace the EPA with the final CPP.
The Registrants are working with the State of Michigan and other stakeholders to shape the CPP compliance plan for Michigan. The final carbon standards for new sources are not expected to have a material impactClean Power Plan rule. Comments on the Registrants, since the Registrants have no plans to build new coal-fired generation and any potential new gas generation will be able to comply with the standards. At the present time, itproposed ACE rule were due on October 31, 2018. It is not possible to determine the potential impact of the final performance standards forEPA's proposed ACE rule on existing power plants due to the multitude of options available to states for compliance that require careful analysis and input from numerous stakeholders. sources at this time.
Pending or future legislation or other regulatory actions could have a material impact on the Registrants'DTE Electric's operations and financial position and the rates the Registrants chargecharged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. The RegistrantsDTE Electric would seek to recover these incremental costs through increased rates charged to theirits utility customers, as authorized by the MPSC.
Increased costs for energy produced from traditional coal-based sources due to recent, pending, and future regulatory initiatives, could also increase the economic viability of energy produced from renewable, natural gas-firedgas fueled generation, and/or nuclear sources, energy efficiencywaste reduction initiatives, and the potential development of market-based trading of carbon instruments which could provide new business opportunities for DTE Energy's utility and non-utility segments. At the present time, it is not possible to quantify the financial impacts of these climate related regulatory initiatives on the Registrants or their customers.
See Items 1. and 2. Business and Properties and Note 1718 to the Consolidated Financial Statements in Item 8 of this Report, "Commitments and Contingencies",Contingencies," for further discussion of Environmental Matters.
EXIT ACTIVITIES
During the fourth quarter of 2015, DTE Energy announced the closure of the Shenango Incorporated coke battery plant in response to a sharp downturn in the North American steel industry. The plant, which is part of the Power and Industrial Projects segment, is located in Pittsburgh, PA. As a result of the closure, DTE Energy recorded a one-time pre-tax non-cash impairment charge of $111 million. The charge included $96 million to fully impair the long-lived assets, employee severance expenses related to the workforce reduction of approximately 170 employees for $3 million, and other expenses, including write downs of inventory, of $12 million. The closure optimizes DTE Energy's coke production at its larger, more efficient facility. Production of coke from the Shenango battery ceased in January 2016. The plant closure will not significantly impact DTE Energy's earnings in future periods. As of December 31, 2015, no amounts have been paid to date under these exit activities. For amounts accrued at December 31, 2015 related to these exit activities, DTE Energy expects future cash payments of approximately $7 million to be made in 2016. DTE Energy anticipates incurring additional costs, including environmental remediation costs, in connection with the closure. An estimate of the amount of the additional costs and timing of the activities cannot be determined at December 31, 2015 as alternatives are currently being evaluated, however, the likelihood of these costs being material to DTE Energy's Consolidated Financial Statements is remote.
OUTLOOKGAS STORAGE AND PIPELINES
Description
Gas Storage and Pipelines owns natural gas storage fields, lateral and gathering pipeline systems, compression and surface facilities, and has ownership interests in interstate pipelines serving the Midwest, Ontario, and Northeast markets. The pipeline and storage assets are primarily supported by long-term, fixed-price revenue contracts.
Properties
Gas Storage and Pipelines holds the following properties:
Property Classification% OwnedDescriptionLocation
Pipelines
Appalachia Gathering System100%116-mile pipeline delivering Marcellus Shale gas to Texas Eastern Pipeline and Stonewall Gas Gathering systemPA and WV
Birdsboro Pipeline100%14-mile pipeline delivering gas supply to the Birdsboro Power PlantPA
Bluestone Pipeline100%64-mile pipeline delivering Marcellus Shale gas to Millennium Pipeline and Tennessee PipelinePA and NY
Michigan gathering systems100%590-mile pipeline system in northern MichiganMI
Millennium Pipeline26%269-mile pipeline serving markets in the NortheastNY
NEXUS Pipeline50%256-mile pipeline to transport Utica and Marcellus shale gas to Ohio, Michigan, and Ontario market centersOH and MI
Stonewall Gas Gathering55%68-mile pipeline connecting Appalachia Gathering System to Columbia PipelineWV
Susquehanna gathering system100%203-mile pipeline delivering Southwestern Energy's Marcellus Shale gas production to Bluestone PipelinePA
Tioga Gas Gathering100%3-mile pipeline delivering production gas to Dominion Transmission interconnectPA
Vector Pipeline40%348-mile pipeline connecting Chicago, Michigan, and Ontario market centersIL, IN, MI, and Ontario
Storage
Washington 10100%75 Bcf of storage capacityMI
Washington 2850%16 Bcf of storage capacityMI


The next few years will be a periodassets of rapid changethese businesses are well integrated with other DTE Energy operations. Pursuant to an operating agreement, DTE Gas provides physical operations, maintenance, and technical support for DTE Energythe Washington 10 and 28 storage facilities and for the Michigan gathering systems.
Regulation
Gas Storage and Pipelines operates natural gas storage facilities in Michigan as intrastate facilities regulated by the MPSC, and provides intrastate storage and related services pursuant to an MPSC-approved tariff. Gas Storage and Pipelines also provides interstate services in accordance with an Operating Statement on file with the FERC. Vector, Millennium, Birdsboro, and NEXUS Pipelines provide interstate transportation services in accordance with their FERC-approved tariffs. In addition, NEXUS and Vector are subject to applicable laws, rules, and regulations in Canada. Gas Storage and Pipelines' gathering and pipeline assets are subject to the rules and regulations of various state utility commissions.
Strategy and Competition
Gas Storage and Pipelines expects to continue its steady growth plan by expanding existing assets, acquiring and/or developing new assets that are typically supported with long-term customer commitments. The focus will be on opportunities in the Midwest to Northeast region to supply natural gas to meet growing demand and displace less attractive supply from certain regions in North America. Much of the growth in demand for natural gas is expected to occur in the eastern Canada and the northeast U.S. regions. Gas Storage and Pipelines believes that the Vector, Millennium, and NEXUS Pipelines are well positioned to provide access routes and low-cost expansion options to these markets due to growth in production from the Marcellus/Utica Shales in Pennsylvania and West Virginia. Gas Storage and Pipelines has agreements with key producers that support its Bluestone Pipeline, Susquehanna gathering, Tioga gathering, AGS, and SGG businesses. Gas Storage and Pipelines is evaluating new pipeline and storage investment opportunities that could include additional pipeline and gathering expansions, laterals, compression, and other Marcellus/Utica shale midstream development or partnering opportunities.
Gas Storage and Pipelines has competition from other pipelines and storage providers. Operations are dependent upon a limited number of customers, and the loss of any one or a few customers could have a material adverse effect on the results of Gas Storage and Pipelines.
POWER AND INDUSTRIAL PROJECTS
Description
Power and Industrial Projects is comprised primarily of projects that deliver energy industry. DTE Energy's strong utility base, combinedand utility-type products and services to industrial, commercial, and institutional customers, produce reduced emissions fuel, and sell electricity and gas from renewable energy projects. This business segment provides services using project assets usually located on or near the customers' premises in the steel, automotive, pulp and paper, airport, chemical, and other industries as follows:
Industrial Energy Services
Steel and Petroleum Coke — Power and Industrial Projects produces metallurgical coke from a coke battery with its integrated non-utility operations, position it well for long-term growth.a capacity of 1.0 million tons per year and has an investment in a second coke battery with a capacity of 1.2 million tons per year. Power and Industrial Projects also provides pulverized coal and petroleum coke to the steel, pulp and paper, and other industries.

28On-Site Energy — Power and Industrial Projects provides power generation, steam production, chilled water production, wastewater treatment, and compressed air supply to industrial customers. Power and Industrial Projects also provides utility-type services using project assets usually located on or near the customers' premises in the automotive, airport, chemical, and other industries.




Looking forward,Renewable Energy
Wholesale Power and Renewables — Power and Industrial Projects holds ownership interests in, and operates, five renewable generating plants with a capacity of 217 MWs. The electric output is sold under long-term power purchase agreements.
Renewable Gas Recovery — Power and Industrial Projects has ownership interests in, and operates, twenty-three gas recovery sites in nine different states. The sites recover methane from landfills and agricultural businesses and convert the gas to generate electricity, replace fossil fuels in industrial and manufacturing operations, or refine to pipeline-quality gas, which can then be used as vehicle fuel.
Reduced Emissions Fuel
Reduced Emissions Fuel — Power and Industrial Projects has constructed and placed in service REF facilities at ten sites including facilities located at seven third-party owned coal-fired power plants. DTE Energy will focus on several areas that are expected to improve future performance:
electrichas sold membership interests in five of the facilities and gas customer satisfaction;
electric reliability;
rate competitiveness and affordability;
regulatory stability and investment recovery forentered into lease arrangements in three of the electric and gas utilities;
growth of utility asset base;
employee engagement;
cost structure optimization across all business segments;
cash, capital, and liquidity to maintain or improve financial strength; and
investments that integrate assets and leverage skills and expertise.
facilities. In addition, DTE Energy has an agreement to operate an REF facility owned by an outside party located at a third-party owned coal-fired power plant. The facilities blend a proprietary additive with coal used in coal-fired power plants, resulting in reduced emissions of nitrogen oxide and mercury. Qualifying facilities are eligible to generate tax credits for ten years upon achieving certain criteria. The value of a tax credit is adjusted annually by an inflation factor published by the IRS. The value of the tax credit is reduced if the reference price of coal exceeds certain thresholds. The economic benefit of the REF facilities is dependent upon the generation of production tax credits.
Properties and Other
The following are significant properties operated by Power and Industrial Projects:
Business AreasLocationService Type
Industrial Energy Services
Steel and Petroleum Coke
Pulverized Coal OperationsMIPulverized Coal
Coke ProductionMIMetallurgical Coke Supply
Other Investment in Coke Production and Petroleum CokeIN and MSMetallurgical Coke Supply and Pulverized Petroleum Coke
On-Site Energy
AutomotiveIN, MI, NY, and OHElectric Distribution, Chilled Water, Waste Water, Steam, Cooling Tower Water, Reverse Osmosis Water, Compressed Air, Mist, and Dust Collectors
AirportsMI and PAElectricity and Hot and Chilled Water
Chemical ManufacturingKY and OHElectricity, Steam, Natural Gas, Compressed Air, and Wastewater
Consumer ManufacturingOHElectricity, Steam, Wastewater, and Sewer
Business ParkPAElectricity
Hospital and UniversityCA and ILElectricity, Steam, and Chilled Water
Renewable Energy
Pulp and PaperALElectric Generation and Steam
RenewablesCA and MNElectric Generation
Renewable Gas RecoveryAZ, CA, MI, NC, NY, OH, TX, UT, and WIElectric Generation and Renewable Natural Gas
Reduced Emissions FuelMI, OH, IL, PA, TX, and WIREF Supply


 2018 2017 2016
 (In millions)
Production Tax Credits Generated (Allocated to DTE Energy)     
REF$178
 $144
 $103
Renewables7
 6
 8
Renewable Gas Recovery3
 3
 3
 $188
 $153
 $114
Regulation
Certain electric generating facilities within Power and Industrial Projects have market-based rate authority from the FERC to sell power. The facilities are subject to FERC reporting requirements and market behavior rules. Certain projects of Power and Industrial Projects are also subject to the applicable laws, rules, and regulations related to the EPA, U.S. Department of Homeland Security, DOE, and various state utility commissions.
Strategy and Competition
Power and Industrial Projects will continue leveraging its energy-related operating experience and project management capability to develop and grow its steel, on-site energy, and renewable energy businesses, and optimize the REF businesses. Power and Industrial Projects will also continue to pursue opportunities to growprovide asset management and operations services to third parties. There are limited competitors for Power and Industrial Projects' existing disparate businesses who provide similar products and services. Power and Industrial Projects' operations are dependent upon a limited number of customers, and the loss of any one or a few customers could have a material adverse effect on the results of Power and Industrial Projects.
Power and Industrial Projects anticipates building around its core strengths in the markets where it operates. In determining the markets in which to compete, Power and Industrial Projects examines closely the regulatory and competitive environment, new and pending legislation, the number of competitors, and its ability to achieve sustainable margins. Power and Industrial Projects plans to maximize the effectiveness of its related businesses as it expands.
Power and Industrial Projects intends to focus on the following areas for growth:
Providing operating services to owners of on-site industrial power plants;
Acquiring and developing renewable gas recovery facilities, renewable energy projects, and other energy projects.
ENERGY TRADING
Description
Energy Trading focuses on physical and financial power and gas marketing and trading, structured transactions, enhancement of returns from its asset portfolio and optimization of contracted natural gas pipeline transportation, and storage positions. Energy Trading also provides natural gas, power, and related services which may include the management of associated storage and transportation contracts on the customers’ behalf and the supply or purchase of renewable energy credits to various customers. Energy Trading's customer base is predominantly utilities, local distribution companies, pipelines, producers and generators, and other marketing and trading companies. Energy Trading enters into derivative financial instruments as part of its marketing and hedging activities. These financial instruments are generally accounted for under the MTM method, which results in the recognition in earnings of unrealized gains and losses from changes in the fair value of the derivatives. Energy Trading utilizes forwards, futures, swaps, and option contracts to mitigate risk associated with marketing and trading activity, as well as for proprietary trading within defined risk guidelines. Energy Trading also provides commodity risk management services to the other businesses within DTE Energy.
Significant portions of the Energy Trading portfolio are economically hedged. Most financial instruments and physical power and natural gas contracts are deemed derivatives; whereas, natural gas inventory, contracts for pipeline transportation, renewable energy credits, and storage assets are not derivatives. As a result, this segment will experience earnings volatility as derivatives are marked-to-market without revaluing the underlying non-derivative contracts and assets. The business’ strategy is to economically manage the price risk of these underlying non-derivative contracts and assets with futures, forwards, swaps, and options. This results in gains and losses that are recognized in different interim and annual accounting periods.


Regulation
Energy Trading has market-based rate authority from the FERC to sell power and blanket authority from the FERC to sell natural gas at market prices. Energy Trading is subject to FERC reporting requirements and market behavior rules. Energy Trading is also subject to the applicable laws, rules, and regulations related to the CFTC, U.S. Department of Homeland Security, and DOE. In addition, Energy Trading is subject to applicable laws, rules, and regulations in Canada.
Strategy and Competition
DTE Energy's strategy for the Energy Trading business is to deliver value-added services to DTE Energy customers. DTE Energy seeks to manage this business in a disciplined manner complementary to the growth of DTE Energy's other business segments. Energy Trading focuses on physical marketing and the optimization of its portfolio of energy assets. The segment competes with electric and gas marketers, financial institutions, traders, utilities, and other energy providers. The Energy Trading business is dependent upon the availability of capital and an investment grade credit rating. DTE Energy believes it has ample available capital capacity to support Energy Trading activities. DTE Energy monitors its use of capital closely to ensure that its commitments do not exceed capacity. A material credit restriction would negatively impact Energy Trading's financial performance. Competitors with greater access to capital, or at a lower cost, may have a competitive advantage. DTE Energy has risk management and credit processes to monitor and mitigate risk.
CORPORATE AND OTHER
Description
Corporate and Other includes various holding company activities, holds certain non-utility debt, and holds energy-related investments.
ENVIRONMENTAL MATTERS
The Registrants are subject to extensive environmental regulation and expect to continue recovering environmental costs related to utility operations through rates charged to customers. The following table summarizes DTE Energy's, including DTE Electric's, estimated significant future environmental expenditures based upon current regulations. Pending or future reconsiderations of current regulations may impact the estimated expenditures summarized in the table below. The amounts reported in the table do not include any expenditures related to the EPA Clean Power Plan that has been stayed as discussed below. Actual costs to comply could vary substantially. Additional costs may result as the effects of various substances on the environment are studied and governmental regulations are developed and implemented.
 DTE Electric DTE Gas Non-utility Total
 (In millions)
Water$60
 $
 $
 $60
Contaminated and other sites10
 25
 
 35
Coal combustion residuals and effluent limitations guidelines515
 
 
 515
Estimated total future expenditures through 2025$585
 $25
 $
 $610
Estimated 2019 expenditures$30
 $15
 $
 $45
Estimated 2020 expenditures$60
 $5
 $
 $65
Water — The EPA finalized regulations on cooling water intake in August 2014. DTE Electric is conducting studies to determine the best technology for reducing the environmental impacts of the cooling water intake structures at each of its facilities. DTE Electric may be required to install technologies to reduce the impacts of the cooling water intakes.
Contaminated and Other Sites — Prior to the construction of major interstate natural gas pipelines, gas for heating and other uses was manufactured locally from processes involving coal, coke, or oil. The facilities, which produced gas, have been designated as MGP sites. DTE Gas owns, or previously owned, 14 such former MGP sites. DTE Electric owns, or previously owned, three former MGP sites. DTE Energy anticipates the cost amortization methodology approved by the MPSC for DTE Gas, which allows DTE Gas to amortize the MGP costs over a ten-year period beginning with the year subsequent to the year the MGP costs were incurred, will prevent environmental costs from having a material adverse effect on DTE Energy's operations. DTE Electric believes the likelihood of a material change to the accrued amount is remote based on current knowledge of the conditions at each site.


The Registrants are also in the process of cleaning up other sites where contamination is present as a result of historical and ongoing utility operations. These other sites include an engineered ash storage facility, electric distribution substations, gas pipelines, electric generating power plants, and underground and aboveground storage tank locations. Cleanup activities associated with these sites will be conducted over the next several years. Any significant change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for these sites and affect the Registrants' financial position and cash flows and the rates charged to their customers.
Coal Combustion Residuals and Effluent Limitations Guidelines — In April 2015, the EPA published a final rule for the disposal of coal combustion residuals, commonly known as coal ash. The rule became effective in October 2015. The rule is based on the continued listing of coal ash as a non-hazardous waste and relies on various self-implementation design and performance standards. DTE Electric owns and operates three permitted engineered coal ash storage facilities to dispose of coal ash from coal-fired power plants and operates a number of smaller impoundments at its power plants. At certain facilities, the rule requires the installation of monitoring wells, compliance with groundwater standards, and the closure of basins at the end of the useful life of the associated power plant. At other facilities, the rule requires ash laden waters be moved from earthen basins to steel and concrete tanks. In 2018, DTE Electric updated its estimated expenditures to remediate accordingly. On October 12, 2018, a D.C. District Court decision became effective that may affect the timing of closure of coal ash impoundments that are not lined with an engineered liner system. In 2019, the EPA is expected to affirmatively undertake rulemaking to implement the D.C. District Court's decision that will determine any changes to DTE Electric's plans in the operations and closure of coal ash impoundments.
In November 2015, the EPA finalized effluent limitations guidelines for the steam electric power generating industry which requires additional controls to be installed between 2018 and 2023. The initial costs to comply with this rule are under development and estimates are included in the Coal Combustion Residual and Effluent Limitations Guidelines amount in the above table.
On April 12, 2017, the EPA granted a petition for reconsideration of the ELG Rule. The EPA also signed an administrative stay of the ELG Rule’s compliance deadlines for fly ash transport water, bottom ash transport water, and flue gas desulfurization (FGD) wastewater, among others. On June 6, 2017, the EPA published in the Federal Register a proposed rule to postpone certain applicable deadlines within the ELG rule. The final rule was published on September 18, 2017. The final rule nullified the administrative stay but also extended the earliest compliance deadlines for the FGD wastewater and bottom ash transport water until November 1, 2020 in order for the EPA to propose and finalize a new ruling. The ELG compliance requirements and final deadlines for bottom ash transport water and FGD wastewater, and total ELG related compliance costs will not be known until the EPA completes its reconsideration of the ELG Rule.
Air — DTE Electric is subject to the EPA ozone and fine particulate transport, and acid rain regulations that limit power plant emissions of SO2 and NOX. The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to emission controls on fossil-fueled power plants to reduce SO2, NOX, mercury, and other emissions. These rulemakings could require additional controls for SO2, NOX, and other hazardous air pollutants over the next few years. DTE Electric does not anticipate additional capital expenditures to comply with air pollution requirements through 2025, pending the results of future rulemakings.
The EPA has implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, the EPA has finalized performance standards for emissions of carbon dioxide from new and existing fossil-fuel EGUs. In February 2016, the U.S. Supreme Court granted petitioners' requests for a stay of the carbon rules for existing EGUs (also known as the EPA Clean Power Plan) pending final review by the courts. The Clean Power Plan has no legal effect while the stay is in place. In October 2017, the EPA issued a proposal to repeal the Clean Power Plan, and in August 2018 the EPA issued its proposed Affordable Clean Energy rule to replace the Clean Power Plan. In addition, in December 2018, the EPA issued proposed revisions to the carbon dioxide standards for new, modified or reconstructed fossil-fuel fired EGUs. The carbon dioxide standard for new sources are not expected to have a material impact on DTE Electric, since DTE Electric has no plans to build new coal-fired generation and any potential new gas generation will be able to comply with the standards. These proposed rules do not impact DTE Energy's goal to reduce carbon emissions 30% by the early 2020s, 45% by 2030, 75% by 2040, and more than 80% by 2050.


Pending or future legislation or other regulatory actions could have a material impact on DTE Electric's operations and financial position and the rates charged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. DTE Electric would seek to recover these incremental costs through increased rates charged to its utility customers, as authorized by the MPSC.
See Management’s Discussion and Analysis in Item 7 of this Report and Notes 8, 9, and 18 to the Consolidated Financial Statements in Item 8 of this Report, "Asset Retirement Obligations," "Regulatory Matters," and "Commitments and Contingencies."
EMPLOYEES
DTE Energy and its subsidiaries had approximately 10,600 employees as of December 31, 2018, of which approximately 5,200 were represented by unions. DTE Electric had approximately 4,900 employees as of December 31, 2018, of which approximately 2,800 were represented by unions. There are several bargaining units for DTE Energy subsidiaries' represented employees. The majority of represented employees for both DTE Energy and DTE Electric are under contracts that expire in 2020 and 2021.

Item 1A. Risk Factors
There are various risks associated with the operations of the Registrants' utility businesses and DTE Energy's non-utility businesses. To provide a framework to understand the operating environment of the Registrants, below is a brief explanation of the more significant risks associated with their businesses. Although the Registrants have tried to identify and discuss key risk factors, others could emerge in the future. Each of the following risks could affect performance.
The Registrants are subject to rate regulation. Electric and gas rates for the utilities are set by the MPSC and the FERC and cannot be changed without regulatory authorization. The Registrants may be negatively impacted by new regulations or interpretations by the MPSC, the FERC, or other regulatory bodies. The Registrants' ability to recover costs may be impacted by the time lag between the incurrence of costs and the recovery of the costs in customers' rates. Regulators also may decide to disallow recovery of certain costs in customers' rates if they determine that those costs do not meet the standards for recovery under current governing laws and regulations. Regulators may also disagree with the Registrants' rate calculations under the various mechanisms that are intended to mitigate the risk to their utilities related to certain aspects of the business. If the Registrants cannot agree with regulators on an appropriate reconciliation of those mechanisms, it may impact the Registrants' ability to recover certain costs through customer rates. Regulators may also decide to eliminate these mechanisms in future rate cases, which may make it more difficult for the Registrants to recover their costs in the rates charged to customers. The Registrants cannot predict what rates the MPSC will authorize in future rate cases. New legislation, regulations, or interpretations could change how the business operates, impact the Registrants' ability to recover costs through rates or the timing of such recovery, or require the Registrants to incur additional expenses.
Changes to Michigan's electric retail access program could negatively impact the Registrants' financial performance. The State of Michigan currently experiences a hybrid market, where the MPSC continues to regulate electric rates for DTE Electric customers, while alternative electric suppliers charge market-based rates. MPSC rate orders, and energy legislation enacted by the State of Michigan, have placed a 10% cap on the total potential retail access migration. However, even with the legislated 10% cap on participation, there continues to be legislative and financial risk associated with the electric retail access program. Electric retail access migration is sensitive to market price and full service electric price changes. The Registrants are required under current regulation to provide full service to retail access customers that choose to return, potentially resulting in the need for additional generating capacity.


The Registrants' electric distribution system and DTE Energy's gas distribution system are subject to risks from their operation, which could reduce revenues, increase expenses, and have a material adverse effect on their business, financial position, and results of operations. The Registrants' electric distribution and DTE Energy’s gas distribution systems are subject to many operational risks. These operational systems and infrastructure have been in service for many years. Equipment, even when maintained in accordance with good utility practices, is subject to operational failure, including events that are beyond the Registrants' control, and could require significant operation and maintenance expense or capital expenditures to operate efficiently. Because the Registrants’ distribution systems are interconnected with those of third parties, the operation of the Registrants’ systems could be adversely affected by unexpected or uncontrollable events occurring on the systems of such third parties.
DTE Energy's non-utility businesses may not perform to its expectations. DTE Energy relies on non-utility operations for an increasing portion of earnings. If DTE Energy's current and contemplated non-utility investments do not perform at expected levels, DTE Energy could experience diminished earnings and a corresponding decline in shareholder value.
DTE Energy relies on cash flows from subsidiaries. DTE Energy is a holding company. Cash flows from the utility and non-utility subsidiaries are required to pay interest expenses and dividends on DTE Energy debt and securities. Should a major subsidiary not be able to pay dividends or transfer cash flows to DTE Energy, its ability to pay interest and dividends would be restricted.
The Registrants' businesses have safety risks. The Registrants' electric distribution system, power plants, renewable energy equipment, and other facilities, and DTE Energy's gas distribution system, gas infrastructure, and other facilities, could be involved in incidents that result in injury, death, or property loss to employees, customers, third parties, or the public. Although the Registrants have insurance coverage for many potential incidents, depending upon the nature and severity of any incident, they could experience financial loss, damage to their reputation, and negative consequences from regulatory agencies or other public authorities.
Environmental laws and liability may be costly. The Registrants are subject to, and affected by, numerous environmental regulations. These regulations govern air emissions, water quality, wastewater discharge, and disposal of solid and hazardous waste. Compliance with these regulations can significantly increase capital spending, operating expenses, and plant down times, and can negatively affect the affordability of the rates charged to customers.
Uncertainty around future environmental regulations creates difficulty planning long-term capital projects in the Registrants' generation fleet and, for DTE Energy's gas distribution businesses. These laws and regulations require the Registrants to seek a variety of environmental licenses, permits, inspections, and other regulatory approvals. The Registrants could be required to install expensive pollution control measures or limit or cease activities, including the retirement of certain generating plants, based on these regulations. Additionally, the Registrants may become a responsible party for environmental cleanup at sites identified by a regulatory body. The Registrants cannot predict with certainty the amount and timing of future expenditures related to environmental matters because of the difficulty of estimating cleanup costs. There is also uncertainty in quantifying liabilities under environmental laws that impose joint and several liability on potentially responsible parties.
The Registrants may also incur liabilities as a result of potential future requirements to address climate change issues. Proposals for voluntary initiatives and mandatory controls are being discussed both in the United States and worldwide to reduce GHGs such as carbon dioxide, a by-product of burning fossil fuels. If increased regulations of GHG emissions are implemented, the operations of DTE Electric's fossil-fueled generation assets may be significantly impacted. Since there can be no assurances that environmental costs may be recovered through the regulatory process, the Registrants' financial performance may be negatively impacted as a result of environmental matters.
For DTE Energy, future environmental regulation of natural gas extraction techniques, including hydraulic fracturing, being discussed both at the United States federal level and by some states may affect the profitability of natural gas extraction businesses which could affect demand for, and profitability of, DTE Energy's gas transportation businesses.
Threats of cyber incidents, physical security, and terrorism could affect the Registrants' business. Issues may threaten the Registrants such as cyber incidents, physical security, or terrorism that may disrupt the Registrants' operations, and could harm the Registrants' operating results.


Information security risks have increased in recent years as a result of the proliferation of new technologies and the increased sophistication and frequency of cyberattacks, and data security breaches. The Registrants' industry requires the continued operation of sophisticated information and control technology systems and network infrastructure. Despite implementation of security measures, all of the Registrants' technology systems are vulnerable to disability or failures due to cyber incidents, physical security threats, acts of war or terrorism, and other causes, as well as loss of operational control of the Registrants' electric generation and distribution assets and, DTE Energy's gas distribution assets. If the Registrants' information technology systems were to fail and they were unable to recover in a timely way, the Registrants may be unable to fulfill critical business functions, which could have a material adverse effect on the Registrants' business, operating results, and financial condition.
Suppliers, vendors, contractors, and information technology providers have access to systems that support the Registrants’ operations and maintain customer and employee data.  A breach of these third-party systems could adversely affect the business as if it was a breach of our own system.  Also, because the Registrants’ generation and distribution systems are part of an interconnected system, a disruption caused by a cyber incident at another utility, electric generator, system operator, or commodity supplier could also adversely affect the Registrants’ businesses, operating results, and financial condition.
In addition, the Registrants' generation plants and electrical distribution facilities, and DTE Energy's gas pipeline and storage facilities, in particular, may be targets of physical security threats or terrorist activities that could disrupt the Registrants' ability to produce or distribute some portion of their products. The Registrants have increased security as a result of past events and may be required by regulators or by the future threat environment to make investments in security that the Registrants cannot currently predict.
Failure to maintain the security of personally identifiable information could adversely affect the Registrants. In connection with the Registrants' businesses, they collect and retain personally identifiable information of their customers, shareholders, and employees. Customers, shareholders, and employees expect that the Registrants will adequately protect their personal information. The regulatory environment surrounding information security and privacy is increasingly demanding. A significant theft, loss, or fraudulent use of customer, shareholder, employee, or Registrant data by cybercrime or otherwise, could adversely impact the Registrants' reputation, and could result in significant costs, fines, and litigation.
Construction and capital improvements to the Registrants' power facilities, DTE Energy's distribution systems and its Gas Storage and Pipelines business subject them to risk. The Registrants are managing ongoing, and planning future, significant construction and capital improvement projects at the Registrants' multiple power generation and distribution facilities, at DTE Energy's gas distribution system, and at DTE Energy's Gas Storage and Pipelines business. Many factors that could cause delays or increased prices for these complex projects are beyond the Registrants' control, including the cost of materials and labor, subcontractor performance, timing and issuance of necessary permits or approvals (including required certificates from regulatory agencies), construction disputes, impediments to acquiring rights-of-way or land rights on a timely basis and on acceptable terms, cost overruns, and weather conditions. Failure to complete these projects on schedule and on budget for any reason could adversely affect the Registrants' financial performance, operations, or expected investment returns at the affected facilities, businesses and development projects.
Operation of a nuclear facility subjects the Registrants to risk. Ownership of an operating nuclear generating plant subjects the Registrants to significant additional risks. These risks include, among others, plant security, environmental regulation and remediation, changes in federal nuclear regulation, increased capital expenditures to meet industry requirements, and operational factors that can secure opportunitiessignificantly impact the performance and cost of operating a nuclear facility compared to other generation options. Insurance maintained by the Registrants for various nuclear-related risks may not be sufficient to cover the Registrants' costs in the event of an accident or business interruption at the nuclear generating plant, which may affect the Registrants' financial performance. In addition, the Registrants' nuclear decommissioning trust fund, to finance the decommissioning of the nuclear generating plant, may not be sufficient to fund the cost of decommissioning. A decline in market value of assets held in decommissioning trust funds due to poor investment performance or other factors may increase the funding requirements for these obligations. Any increase in funding requirements may have a material impact on the Registrants’ liquidity, financial position, or results of operations.


The supply and/or price of energy commodities and/or related services may impact the Registrants' financial results. The Registrants are dependent on coal for much of their electrical generating capacity as well as uranium for their nuclear operations. DTE Energy's access to natural gas supplies is critical to ensure reliability of service for utility gas customers. DTE Energy's non-utility businesses are also dependent upon supplies and prices of energy commodities and services. Price fluctuations, fuel supply disruptions, and changes in transportation costs, could have a negative impact on the amounts DTE Electric charges utility customers for electricity and DTE Gas charges utility customers for gas, and on the profitability of DTE Energy's non-utility businesses. The Registrants' hedging strategies and regulatory recovery mechanisms may be insufficient to mitigate the negative fluctuations in commodity supply prices in their utility and, for DTE Energy, non-utility businesses, and the Registrants' financial performance may therefore be negatively impacted by price fluctuations. The price of energy also impacts the market for DTE Energy's non-utility businesses that meetcompete with utilities and alternative electric suppliers.
The supply and/or price of other industrial raw and finished inputs and/or related services may impact the Registrants' financial results. The Registrants are dependent on supplies of certain commodities, such as copper and limestone, among others, and industrial materials, and services in order to maintain day-to-day operations and maintenance of their facilities. Price fluctuations, or supply interruptions for these commodities and other items, could have a negative impact on the amounts charged to customers for the Registrants' utility products and, for DTE Energy, on the profitability of the non-utility businesses.
Emerging technologies may have a material adverse effect on the Registrants. Advances in technology that produce power or reduce power consumption include cost-effective renewable energy technologies, distributed generation, energy waste reduction technologies, and energy storage devices. Such developments may impact the price of energy, may affect energy deliveries as customer-owned generation becomes more cost-effective, may require further improvements to our distribution systems to address changing load demands, and could make portions of our electric system power supply and/or distribution facilities obsolete prior to the end of their useful lives. Such technologies could also result in further declines in commodity prices or demand for delivered energy. Each of these factors could materially affect the Registrants’ results of operations, cash flows, or financial position.
Adverse changes in the Registrants' credit ratings may negatively affect them. Regional and national economic conditions, increased scrutiny of the energy industry and regulatory changes, as well as changes in the Registrants' economic performance, could result in credit agencies reexamining their credit ratings. While credit ratings reflect the opinions of the credit agencies issuing such ratings and may not necessarily reflect actual performance, a downgrade in the Registrants' credit ratings below investment grade could restrict or discontinue their ability to access capital markets and could result in an increase in their borrowing costs, a reduced level of capital expenditures, and could impact future earnings and cash flows. In addition, a reduction in the Registrants' credit ratings may require them to post collateral related to various physical or financially settled contracts for the purchase of energy-related commodities, products, and services, which could impact their liquidity.
Poor investment performance of pension and other postretirement benefit plan assets and other factors impacting benefit plan costs could unfavorably impact the Registrants' liquidity and results of operations. The Registrants' costs of providing non-contributory defined benefit pension plans and other postretirement benefit plans are dependent upon a number of factors, such as the rates of return on plan assets, the level of interest rates used to measure the required minimum funding levels of the plans, future government regulation, and the Registrants' required or voluntary contributions made to the plans. The performance of the debt and equity markets affects the value of assets that are held in trust to satisfy future obligations under the Registrants' plans. The Registrants have significant benefit obligations and hold significant assets in trust to satisfy these obligations. These assets are subject to market fluctuations and will yield uncertain returns, which may fall below the Registrants' projected return rates. A decline in the market value of the pension and other postretirement benefit plan assets will increase the funding requirements under the pension and other postretirement benefit plans if the actual asset returns do not recover these declines in the foreseeable future. Additionally, the pension and other postretirement benefit plan liabilities are sensitive to changes in interest rates. If interest rates decrease, the liabilities increase, resulting in increasing benefit expense and funding requirements. Also, if future increases in pension and other postretirement benefit costs as a result of reduced plan assets are not recoverable from the Registrants' utility customers, the results of operations and financial position of the Registrants could be negatively affected. Without sustained growth in the plan investments over time to increase the value of plan assets, the Registrants could be required to fund these plans with significant amounts of cash. Such cash funding obligations could have a material impact on the Registrants' cash flows, financial position, or results of operations.


The Registrants' ability to access capital markets is important. The Registrants' ability to access capital markets is important to operate their businesses and to fund capital investments. Turmoil in credit markets may constrain the Registrants' ability, as well as the ability of their subsidiaries, to issue new debt, including commercial paper, and refinance existing debt at reasonable interest rates. In addition, the level of borrowing by other energy companies, and the market as a whole, could limit the Registrants' access to capital markets. The Registrants' long-term revolving credit facilities do not expire until 2022, but the Registrants regularly access capital markets to refinance existing debt or fund new projects at the Registrants' utilities and DTE Energy's non-utility businesses, and the Registrants cannot predict the pricing or demand for those future transactions.
DTE Energy's participation in energy trading markets subjects it to risk. Events in the energy trading industry have increased the level of scrutiny on the energy trading business and the energy industry as a whole. In certain situations, DTE Energy may be required to post collateral to support trading operations, which could be substantial. If access to liquidity to support trading activities is curtailed, DTE Energy could experience decreased earnings potential and cash flows. Energy trading activities take place in volatile markets and expose DTE Energy to risks related to commodity price movements, deviations in weather, and other related risks. DTE Energy's trading business routinely has speculative trading positions in the market, within strict policy guidelines DTE Energy sets, resulting from the management of DTE Energy's business portfolio. To the extent speculative trading positions exist, fluctuating commodity prices can improve or diminish DTE Energy's financial results and financial position. DTE Energy manages its strategic, financial,exposure by establishing and enforcing strict risk limits and risk criteria.management procedures. During periods of extreme volatility, these risk limits and risk management procedures may not work as planned and cannot eliminate all risks associated with these activities.
Weather significantly affects operations. At both utilities, deviations from normal hot and cold weather conditions affect the Registrants' earnings and cash flows. Mild temperatures can result in decreased utilization of the Registrants' assets, lowering income and cash flows. At DTE Electric, ice storms, tornadoes, or high winds can damage the electric distribution system infrastructure and power generation facilities and require it to perform emergency repairs and incur material unplanned expenses. The expenses of storm restoration efforts may not be fully recoverable through the regulatory process. DTE Gas can experience higher than anticipated expenses from emergency repairs on its gas distribution infrastructure required as a result of weather related issues.
Unplanned power plant outages may be costly. Unforeseen maintenance may be required to safely produce electricity or comply with environmental regulations. As a result of unforeseen maintenance, the Registrants may be required to make spot market purchases of electricity that exceed the costs of generation. The Registrants' financial performance may be negatively affected if unable to recover such increased costs.
Regional, national, and international economic conditions can have an unfavorable impact on the Registrants. The Registrants' utility and DTE Energy's non-utility businesses follow the economic cycles of the customers they serve and credit risk of counterparties they do business with. Should the financial conditions of some of DTE Energy's significant customers deteriorate as a result of regional, national or international economic conditions, reduced volumes of electricity and gas, and demand for energy services DTE Energy supplies, collections of accounts receivable, reductions in federal and state energy assistance funding, and potentially higher levels of lost gas or stolen gas and electricity could result in decreased earnings and cash flows.
Renewable portfolio standards and energy waste reduction programs may affect the Registrants' business. The Registrants are subject to existing Michigan, and potential future, federal legislation and regulation requiring them to secure sources of renewable energy. The Registrants have complied with the existing federal and state legislation, but do not know what requirements may be added by federal or state legislation in the future. In addition, the Registrants expect to comply with new Michigan legislation increasing the percentage of power required to be provided by renewable energy sources. The Registrants cannot predict the financial impact or costs associated with complying with potential future legislation and regulations. Compliance with these requirements can significantly increase capital expenditures and operating expenses and can negatively affect the affordability of the rates charged to customers.
The Registrants are also required by Michigan legislation to implement energy waste reduction measures and provide energy waste reduction customer awareness and education programs. These requirements necessitate expenditures, and implementation of these programs creates the risk of reducing the Registrants' revenues as customers decrease their energy usage. The Registrants cannot predict how these programs will impact their business and future operating results.


Failure to attract and retain key executive officers and other skilled professional and technical employees could have an adverse effect on the Registrants operations. The Registrants' businesses are dependent on their ability to attract and retain skilled employees. Competition for skilled employees in some areas is high, and the inability to attract and retain these employees could adversely affect the Registrants' business and future operating results. In addition, the Registrants have an aging utility workforce, and the failure of a successful transfer of knowledge and expertise could negatively impact their operations.
A work interruption may adversely affect the Registrants. There are several bargaining units for DTE Energy's approximately 5,200 and DTE Electric's approximately 2,800 represented employees. The majority of represented employees are under contracts that expire in 2020 and 2021. A union choosing to strike would have an impact on the Registrants' businesses. The Registrants are unable to predict the effect a work stoppage would have on their costs of operations and financial performance.
DTE Energy's ability to utilize production tax credits may be limited. To reduce U.S. dependence on imported oil, the Internal Revenue Code provides production tax credits as an incentive for taxpayers to produce fuels and electricity from alternative sources. DTE Energy generated production tax credits from coke production, renewable gas recovery, reduced emission fuel, and gas production operations, and for the Registrants, renewable energy generation. If the Registrants' production tax credits were disallowed in whole or in part as a result of an IRS audit or changes in tax law, there could be additional tax liabilities owed for previously recognized tax credits that could significantly impact the Registrants' earnings and cash flows.
If DTE Energy's goodwill becomes impaired, it may be required to record a charge to earnings. DTE Energy annually reviews the carrying value of goodwill associated with acquisitions it has made for impairment. Factors that may be considered for purposes of this analysis include any change in circumstances indicating that the carrying value of DTE Energy goodwill may not be recoverable, such as a decline in stock price and market capitalization, future cash flows, and slower growth rates in the industry. DTE Energy cannot predict the timing, strength, or duration of any economic slowdown or subsequent recovery, worldwide or in the economy or markets in which it operates; however, when events or changes in circumstances indicate that the carrying value of these assets may not be recoverable, DTE Energy may take a non-cash impairment charge, which could potentially materially impact DTE Energy's results of operations and financial position.
The Registrants may not be fully covered by insurance. The Registrants have a comprehensive insurance program in place to provide coverage for various types of risks, including catastrophic damage as a result of severe weather or other natural disasters, war, terrorism, or a combination of other significant unforeseen events that could impact the Registrants' operations. Economic losses might not be covered in full by insurance, or the Registrants' insurers may be unable to meet contractual obligations.

Item 1B. Unresolved Staff Comments
None.

RESULTS

Item 3. Legal Proceedings
In March 2018, the Trenton Channel Power Plant experienced exceedances of its mercury emission limits. The exceedances were reported to the EPA and the MDEQ. On September 12, 2018, the EPA issued a NOV. DTE Electric is currently working with the EPA to address the NOV.  At this time, DTE Electric cannot predict the impact of the NOV.
For more information on legal proceedings and matters related to the Registrants, see Notes 9 and 18 to the Consolidated Financial Statements in Item 8 of this Report, "Regulatory Matters" and "Commitments and Contingencies," respectively.

Item 4. Mine Safety Disclosures
Not applicable.


Part II
Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters, and Issuer Purchases of Equity Securities
DTE Energy common stock is listed under the ticker symbol "DTE" on the New York Stock Exchange, which is the principal market for such stock.
At December 31, 2018, there were 181,925,281 shares of DTE Energy common stock outstanding. These shares were held by a total of 51,338 shareholders of record.
All of the 138,632,234 issued and outstanding shares of DTE Electric common stock, par value $10 per share, are owned by DTE Energy, and constitute 100% of the voting securities of DTE Electric. Therefore, no market exists for DTE Electric's common stock.
For information on DTE Energy dividend restrictions, see Note 16 to the Consolidated Financial Statements in Item 8 of this Report, "Short-Term Credit Arrangements and Borrowings."
All of DTE Energy's equity compensation plans that provide for the annual awarding of stock-based compensation have been approved by shareholders. For additional detail, see Note 21 to the Consolidated Financial Statements in Item 8 of this Report, "Stock-Based Compensation."
See the following table for information as of December 31, 2018:
 Number of Securities to be Issued Upon Exercise of Outstanding Options Weighted-Average Exercise Price of Outstanding Options Number of Securities Remaining Available for Future Issuance Under Equity Compensation Plans
Plans approved by shareholders52,100
 $43.30
 2,897,674
UNREGISTERED SALES OF OPERATIONSDTE ENERGY EQUITY SECURITIES AND USE OF PROCEEDS
Purchases of DTE Energy Equity Securities by the Issuer and Affiliated Purchasers
The following sections provide a detailed discussiontable provides information about DTE Energy's purchases of equity securities that are registered by DTE Energy pursuant to Section 12 of the operating performance and future outlookExchange Act of DTE Energy's segments. Segment information, described below, includes intercompany revenues and expenses, and other income and deductions that are eliminated in1934 for the Consolidated Financial Statements.quarter ended December 31, 2018:
 2015 2014 2013
 (In millions)
Net Income (Loss) Attributable to DTE Energy by Segment:     
Electric$542
 $528
 $484
Gas132
 140
 143
Gas Storage and Pipelines107
 82
 70
Power and Industrial Projects16
 90
 66
Energy Trading(22) 122
 (58)
Corporate and Other(48) (57) (44)
Net Income Attributable to DTE Energy Company$727
 $905
 $661
 
Number of Shares Purchased(a)
 
Average Price
Paid per Share
(a)
 Number of Shares Purchased as Part of Publicly Announced
Plans or Programs
 Average Price Paid per Share Maximum Dollar
Value that May
Yet Be Purchased Under the Plans or Programs
10/01/2018 — 10/31/2018143
 $110.14
 
 
 
11/01/2018 — 11/30/2018
 $
 
 
 
12/01/2018 — 12/31/2018
 $
 
 
 
Total143
  
 
  
  

(a)Represents shares of DTE Energy common stock withheld to satisfy income tax obligations upon the vesting of restricted stock based on the price in effect at the grant date.

ELECTRIC
COMPARISON OF CUMULATIVE FIVE YEAR TOTAL RETURN
Total Return to DTE Energy Shareholders
(Includes reinvestment of dividends)
  Annual Return Percentage
Year Ended December 31,
Company/Index 2014 2015 2016 2017 2018
DTE Energy Company 34.61
 (3.77) 26.93
 14.59
 4.19
S&P 500 Index 13.69
 1.38
 11.95
 21.82
 (4.39)
S&P 500 Multi-Utilities Index 28.94
 (1.73) 18.56
 12.09
 1.77
  Indexed Returns
Year Ended December 31,
  Base Period          
Company/Index 2013 2014 2015 2016 2017 2018
DTE Energy Company 100.00
 134.61
 129.54
 164.41
 188.40
 196.30
S&P 500 Index 100.00
 113.69
 115.26
 129.04
 157.19
 150.29
S&P 500 Multi-Utilities Index 100.00
 128.94
 126.71
 150.22
 168.38
 171.35
dteenergy20_chart-06124a04.jpg



Item 6. Selected Financial Data
The following selected financial data of DTE Energy should be read in conjunction with the accompanying Management’s NarrativeDiscussion and Analysis in Item 7 of Resultsthis Report and Combined Notes to Consolidated Financial Statements in Item 8 of Operations discussionthis Report. This information has been omitted for DTE Electric is presented in a reduced disclosure format in accordance withper General Instruction I (2) (a) of Form 10-K for wholly-owned subsidiaries.

29



The Electric segment consists principally of DTE Electric. Results for Electric segment with a reconciliation to DTE Electric are discussed below:subsidiaries (reduced disclosure format).
 2015 2014 2013
 (In millions)
Operating Revenues — Utility operations$4,901
 $5,283
 $5,199
Fuel and purchased power — utility1,573
 1,705
 1,668
Gross Margin3,328
 3,578
 3,531
Operation and maintenance1,344
 1,332
 1,377
Depreciation and amortization637
 933
 902
Taxes other than income277
 268
 261
Asset (gains) losses and impairments, net
 (1) (3)
Operating Income1,070
 1,046
 994
Other (Income) and Deductions238
 222
 258
Income Tax Expense290
 296
 252
Segment Net Income Attributable to DTE Energy Company$542
 $528
 $484
Reconciliation of Segment Net Income Attributable to DTE Energy Company to DTE Electric Net Income2
 4
 3
DTE Electric Net Income Attributable to DTE Energy Company$544
 $532
 $487
See DTE Electric's Consolidated Statements of Operations in Item 8 of this report for a complete view of its results.
Gross Margin decreased $250 million in 2015 and increased $47 million in 2014. Revenues associated with certain mechanisms and surcharges are offset by related expenses elsewhere in the Registrants' Consolidated Statements of Operations.
The following table details changes in various gross margin components relative to the comparable prior period:
 2015 2014
 (In millions)
Implementation of new rates$117
 $
Base sales, inclusive of weather effect24
 (48)
Renewable energy program3
 20
PSCR disallowance(19) 
Securitization bond and tax surcharge(376) (10)
Amortization of refundable revenue decoupling/deferred gain
 63
Low-income energy assistance surcharge
 17
Regulatory mechanisms and other1
 5
Increase (decrease) in Electric segment Gross Margin$(250) $47
Reconciliation of Electric segment Gross Margin to DTE Electric Gross Margin(1) 
Increase (decrease) in DTE Electric Gross Margin$(251) $47

30



 2015 2014 2013
 (In thousands of MWh)
DTE Electric Sales     
Residential15,001
 14,940
 15,273
Commercial17,192
 16,792
 16,661
Industrial9,690
 10,199
 10,303
Other291
 517
 942
 42,174
 42,448
 43,179
Interconnection sales (a)4,108
 3,630
 3,883
Total DTE Electric Sales46,282
 46,078
 47,062
      
DTE Electric Deliveries 
  
  
Retail and Wholesale42,174
 42,448
 43,179
Electric retail access, including self generators (b)4,899
 5,033
 5,200
Total DTE Electric Sales and Deliveries47,073
 47,481
 48,379
 2018 2017 2016 2015 2014
 (In millions, except per share amounts)
Operating Revenues$14,212
 $12,607
 $10,630
 $10,337
 $12,301
Net Income Attributable to DTE Energy Company(a)
$1,120
 $1,134
 $868
 $727
 $905
Diluted Earnings Per Common Share$6.17
 $6.32
 $4.83
 $4.05
 $5.10
Financial Information         
Dividends declared per share of common stock$3.60
 $3.36
 $3.06
 $2.84
 $2.69
Total Assets$36,288
 $33,767
 $32,041
 $28,662
 $27,827
Long-Term Debt(b)
$12,134
 $12,185
 $11,269
 $8,760
 $8,271
Shareholders’ equity$10,237
 $9,512
 $9,011
 $8,772
 $8,327

(a)Represents power that is not distributed by DTE Electric.The 2017 results include a $105 million net income tax benefit related to the enactment of the TCJA.
(b)Represents deliveries for self generators that have purchased power from alternative energy suppliers to supplement their power requirements.Long-Term Debt includes Capital lease obligations and excludes debt due within one year.

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations
The following combined discussion is separately filed by DTE Energy and DTE Electric. However, DTE Electric residential and commercial sales increased due primarilydoes not make any representations as to favorable weather, while industrial sales decreased due primarily to lower steel customer load.
Operation and maintenance expense increased $12 million in 2015 and decreased $45 million in 2014. The increase in 2015 is primarily due to increased power plant generation expenses of $28 million, increased line clearance expenses of $25 million, increased distribution operations expenses of $13 million, and $18 million of expensesinformation related to the transition of PLD customerssolely to DTE Electric'sEnergy or the subsidiaries of DTE Energy other than itself.
EXECUTIVE OVERVIEW
DTE Energy is a diversified energy company with 2018 Operating Revenues of approximately $14.2 billion and Total Assets of approximately $36.3 billion. DTE Energy is the parent company of DTE Electric and DTE Gas, regulated electric and natural gas utilities engaged primarily in the business of providing electricity and natural gas sales, distribution, system effective July 1, 2014, partially offset by decreased storm restoration expenses of $63 million and decreased employee benefits of $7 million. storage services throughout Michigan. DTE Energy operates three energy-related non-utility segments with operations throughout the United States.
The following table summarizes DTE Energy's financial results:
 Years Ended December 31,
 2018 2017 2016
 (In millions, except per share amounts)
Net Income Attributable to DTE Energy Company$1,120
 $1,134
 $868
Diluted Earnings per Common Share$6.17
 $6.32
 $4.83
The decrease in 2014 is primarily due to decreased employee benefit expenses of $68 million, decreased distribution operations expenses of $36 million, and decreased power plant generation expenses of $7 million, partially offset by higher storm restoration expenses of $19 million, increased low-income energy assistance of $17 million, $17 million of expenses related to the transition of PLD customers2018 Net Income Attributable to DTE Electric's distribution system, and increased energy optimization and renewable energy expenses of $13 million. The MPSC approved a TRM that provides for recovery of the deferred net incremental revenue requirement associated with the transition of former PLD customers that is reflected in the Depreciation and amortization line in DTE Electric's Consolidated Statements of Operations.
Depreciation and amortizationexpense decreased $296 million in 2015 and increased $31 million in 2014. The 2015 decrease was due to $342 million of decreased amortization of regulatory assets related to Securitization and $15 million associated with the TRM, partially offset by $61 million of increased expenses due to an increased depreciable base. The 2014 increase was due to $42 million of increased expense due to an increased depreciable base and increased amortization of regulatory assets of $3 million, primarily related to Securitization, partially offset by $14 million associated with the TRM.
Other (Income) and Deductions increased $16 million in 2015 and decreased $36 million in 2014. The increase in 2015Energy Company was primarily due to lower investment earnings in the Gas Storage and Pipelines, Energy Trading, and Corporate and Other segments, partially offset by higher earnings in the Electric, Gas, and Power and Industrial Projects segments. The 2018 decrease was partially attributable to true-up adjustments for the remeasurement of $11deferred taxes of $21 million as the adjustments increased Income Tax Expense, of which $17 million was attributable to the regulated utilities and higher interest expense of $8 million.increased Regulatory liabilities. The decreaseincrease in 20142017 Net Income Attributable to DTE Energy Company was primarily due to decreased interest expenseshigher earnings in the Gas Storage and Pipelines, Energy Trading, and Power and Industrial Projects segments, partially offset by lower earnings in the Corporate and Other segment. The 2017 increase was also due to $105 million of $18 million and the 2013 contributionnet income tax benefit related to the enactment of the TCJA.
Please see detailed explanations of segment performance in the following "Results of Operations" section.
DTE Energy Foundation of $18 million.
Outlook DTE Electric will continue to move forward in its effortsEnergy's strategy is to achieve operational excellence, sustainedlong-term earnings growth, a strong cash flows,balance sheet, and earn its authorized return on equity. an attractive dividend yield.


DTE ElectricEnergy's utilities are investing capital to improve customer reliability through investments in base infrastructure and new generation, and to comply with environmental requirements. DTE Energy expects that planned significant capital investments will result in earnings growth. Looking forward, additional factors may impact earnings such as weather, the outcome of regulatory proceedings, benefit plan design changes, investment returns and changes in discount rate assumptions in benefit plans and health care costs, uncertainty of legislative or regulatory actions regarding climate change and electric retail access, and effects of energy efficiency programs. DTE Electric residential and commercial sales have increased due primarily to improved economic activity and have been substantially offset by energy efficiency measures taken by customers. DTE Electric expects to continue its efforts to improve productivity and decrease costs while improving customer satisfaction with consideration of customer rate affordability.

31



DTE Electric filed a rate case with the MPSC on February 1, 2016 requesting an increase in base rates of $344 million based on a projected twelve-month period ending July 31, 2017. The requested increase in base rates is due primarily to an increase in net plant resulting from infrastructure investments, environmental compliance, and reliability improvement projects. The rate filing also includes projected changes in sales, operation and maintenance expenses, and working capital. The rate filing also requests an increase in return on equity from 10.3% to 10.5% on a capital structure of 50% equity and 50% debt. DTE Electric anticipates self-implementing a rate increase in August 2016 with an MPSC order expected by February 2017.
GAS
The Gas segment consists principally of DTE Gas. Gas results are discussed below:
 2015 2014 2013
 (In millions)
Operating Revenues — Utility operations$1,376
 $1,636
 $1,474
Cost of gas — utility526
 725
 624
Gross Margin850
 911
 850
Operation and maintenance430
 456
 429
Depreciation and amortization104
 99
 95
Taxes other than income62
 61
 56
Operating Income254
 295
 270
Other (Income) and Deductions50
 77
 50
Income Tax Expense72
 78
 77
Net Income Attributable to DTE Energy Company$132
 $140
 $143
Gross Margin decreased $61 million in 2015 and increased $61 million in 2014. Revenues associated with certain mechanisms and surcharges are offset by related expenses elsewhere in DTE Energy's Consolidated Statements of Operations.
The following table details changes in various gross margin components relative to the comparable prior period:
 2015 2014
 (In millions)
Weather$(64) $31
Infrastructure recovery mechanism12
 7
Home protection program4
 7
Revenue decoupling mechanism7
 (3)
Midstream storage and transportation revenues(10) 6
Other(10) 13
Increase (decrease) in Gross Margin$(61) $61
 2015 2014 2013
Gas Markets (in Bcf)     
Gas sales122
 138
 128
End-user transportation169
 167
 157
 291
 305
 285
Intermediate transportation289
 305
 300
Total Gas sales580
 610
 585
Operation and maintenanceexpense decreased $26 million in 2015 and increased $27 million in 2014. The decrease in 2015 is primarily due to decreased gas operations expenses of $12 million, decreased employee benefits expenses of $10 million, decreased transmission expenses of $3 million, and decreased uncollectible expenses of $3 million. The increase in 2014 is primarily due to increased gas operations expenses of $32 million, increased uncollectible expenses of $4 million, and increased corporate administrative expenses of $3 million, partially offset by decreased employee benefit expenses of $10 million and reduced energy optimization expenses of $2 million.

32



Other (Income) and Deductions decreased $27 million in 2015 and increased $27 million in 2014. The decrease in 2015 is primarily due to the 2014 contribution to the DTE Energy Foundation and other charitable organizations. The increase in 2014 is primarily due to contributions to the DTE Energy Foundation and other charitable organizations in 2014.
Outlook — DTE Gas will continue to move forward in its effortsfocused on executing plans to achieve operational excellence sustainedand customer satisfaction with a focus on customer affordability. DTE Energy operates in a constructive regulatory environment and has solid relationships with its regulators.
In May 2017, DTE Energy announced its plan to reduce carbon emissions. This goal will be attained by cutting carbon emissions 30% by the early 2020s, 45% by 2030, 75% by 2040, and more than 80% by 2050. To achieve this reduction, DTE Energy will transition away from coal-powered sources and incorporate more renewable energy, energy waste reduction projects, demand response, and natural gas fueled generation. DTE Energy has already begun the transition in the way it produces power through the continued retirement of its aging coal-fired plants. In May 2018, DTE Energy announced its plans to accelerate its clean energy initiatives by targeting at least a 50% clean energy goal by 2030 to be achieved through a combination of investments in renewable energy and energy waste reduction projects. Refer to the "Capital Investments" section below for further discussion.
DTE Energy has significant investments in non-utility businesses. DTE Energy employs disciplined investment criteria when assessing growth opportunities that leverage its assets, skills, and expertise, and provides diversity in earnings and geography. Specifically, DTE Energy invests in targeted energy markets with attractive competitive dynamics where meaningful scale is in alignment with its risk profile. DTE Energy expects growth opportunities in the Gas Storage and Pipelines and Power and Industrial Projects segments.
A key priority for DTE Energy is to maintain a strong balance sheet which facilitates access to capital markets and reasonably priced short-term and long-term financing. Near-term growth will be funded through internally generated cash flows and earn its authorized return onthe issuance of debt and equity. DTE Gas expectsEnergy has an enterprise risk management program that, plannedamong other things, is designed to monitor and manage exposure to earnings and cash flow volatility related to commodity price changes, interest rates, and counterparty credit risk.
CAPITAL INVESTMENTS
DTE Energy's utility businesses require significant infrastructure capital investments will result in earnings growth. Looking forward, additional factors may impact earnings such as weather,to maintain and improve the outcome of regulatory proceedings, benefit plan design changes,electric generation and investment returnselectric and changes in discount rate assumptions in benefit plansnatural gas distribution infrastructure and health care costs. DTE Gas expects to continue its efforts to improve productivitycomply with environmental regulations and decrease costs while improving customer satisfaction with consideration of customer rate affordability.renewable energy requirements.
DTE GasElectric's capital investments over the 2019-2023 period are estimated at $11.3 billion comprised of $4.0 billion for capital replacements and other projects, $4.6 billion for distribution infrastructure, and $2.7 billion for new generation. DTE Electric has retired four coal-fired generation units at the Trenton Channel, River Rouge, and St Clair facilities and has announced plans to retire its remaining thirteen coal-fired generating units. Seven of these coal-fired generating units will be retired through 2023 at the Trenton Channel, River Rouge, and St. Clair facilities. The remaining coal-fired generating units at the Belle River and Monroe facilities are expected to be retired by 2040. The retired facilities will be replaced with renewables, energy waste reduction, demand response, and natural gas fueled generation. In April 2018, DTE Electric received approval from the MPSC to build a natural gas fueled combined cycle generation facility to provide approximately 1,100 megawatts of energy beginning in 2022. In August 2018, DTE Electric began construction on its natural gas fueled combined cycle generation facility. In March 2018, DTE Electric filed a rate caseits 2018 Renewable Energy Plan with the MPSC on December 18, 2015 requesting an increaseproposing approximately 1,000 additional megawatts of energy from new wind and solar projects to be completed by 2022. The MPSC had previously approved 300 of the 1,000 additional megawatts for wind projects in base rates of $183 million based on a projected twelve-month period ending October 31, 2017. The requested increase in base rates is due primarily to an increase in net plant of $800 million, inclusive of IRM capital investments being recovered through approved IRM surcharge filings. The rate filing also includes projected changes in sales, operation and maintenance expenses, and working capital. The rate filing also requests an increase in return on equity from 10.5% to 10.75% on a capital structure of 52% equity and 48% debt. DTE Gas anticipates self-implementing a rate increase in November 2016 with an MPSC order expected by Decemberreceived in September 2016. ConcurrentIn January 2018, DTE Electric filed with the MPSC order in this rate case,its five-year distribution operations investment and maintenance plan to improve system reliability. DTE Electric plans to seek regulatory approval for capital expenditures consistent with prior ratemaking treatment. For further discussion of regulatory matters, see Note 9 to the existing IRM surcharge will be terminated. However, in this rate case filing,Consolidated Financial Statements, "Regulatory Matters."
DTE Gas' capital investments over the 2019-2023 period are estimated at $2.5 billion comprised of $1.2 billion for base infrastructure, and $1.3 billion for gas main renewal, meter move out, and pipeline integrity programs. DTE Gas plans to seek regulatory approval for capital expenditures consistent with ratemaking treatment.
DTE Energy's non-utility businesses' capital investments are primarily for expansion, growth, and ongoing maintenance. Gas Storage and Pipelines' capital investments over the 2019-2023 period are estimated at $4.0 billion to $5.0 billion for gathering and pipeline investments and expansions. Power and Industrial Projects' capital investments over the 2019-2023 period are estimated at $1.0 billion to $1.4 billion for industrial energy services and RNG projects.


ENVIRONMENTAL MATTERS
The Registrants are subject to extensive environmental regulation. Additional costs may result as the effects of various substances on the environment are studied and governmental regulations are developed and implemented. Actual costs to comply could vary substantially. The Registrants expect to continue recovering environmental costs related to utility operations through rates charged to customers, as authorized by the MPSC.
Air — DTE Electric is subject to the EPA ozone and fine particulate transport and acid rain regulations that limit power plant emissions of SO2 and NOX. The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to controls on fossil-fueled power plants to reduce SO2, NOX, mercury, and other emissions. Additional rulemakings may occur over the next few years which could require additional controls for SO2, NOX, and other hazardous air pollutants. To comply with existing requirements, DTE Electric spent approximately $2.4 billion through 2018. DTE Electric does not anticipate additional capital expenditures through 2025.
The EPA has implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, in 2015 the EPA finalized performance standards for emissions of carbon dioxide from new and existing EGUs. In February 2016, the U.S. Supreme Court granted petitioners' requests for a stay of the carbon rules for existing EGUs (also known as the EPA Clean Power Plan) pending final review by the courts. The Clean Power Plan has no legal effect while the stay is in place. On March 28, 2017, a presidential executive order was issued on "Promoting Energy Independence and Economic Growth." The order instructs the EPA to review, and if appropriate, suspend, revise or rescind the Clean Power Plan rule. Following the issuance of this order, the federal government requested the U.S. Court of Appeals for the D.C. Circuit to implementhold all legal challenges in abeyance until the review of these regulations is completed. On October 10, 2017, the EPA proposed to rescind the Clean Power Plan and announced its intent to issue an ANPR seeking input as to whether it should replace the rule and, if so, what form it should take. In August 2018, the EPA proposed revised emission guidelines for GHGs from existing electric utility generating units. The proposed rule, named the Affordable Clean Energy (ACE) rule, is intended to replace the Clean Power Plan rule. Comments on the proposed ACE rule were due on October 31, 2018. It is not possible to determine the potential impact of the EPA's proposed ACE rule on existing sources at this time.
Pending or future legislation or other regulatory actions could have a material impact on DTE Electric's operations and financial position and the rates charged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. DTE Electric would seek to recover these incremental costs through increased rates charged to its utility customers, as authorized by the MPSC.
Increased costs for energy produced from traditional coal-based sources due to recent, pending, and future regulatory initiatives, could also increase the economic viability of energy produced from renewable, natural gas fueled generation, and/or nuclear sources, energy waste reduction initiatives, and the potential development of market-based trading of carbon instruments which could provide new IRM surchargebusiness opportunities for DTE Energy's utility and non-utility segments. At the present time, it is not possible to become effectivequantify the financial impacts of these climate related regulatory initiatives on the Registrants or their customers.
See Items 1. and 2. Business and Properties and Note 18 to the Consolidated Financial Statements in January 2017.Item 8 of this Report, "Commitments and Contingencies," for further discussion of Environmental Matters.


GAS STORAGE AND PIPELINES
The Description
Gas Storage and Pipelines segment consists ofowns natural gas storage fields, lateral and gathering pipeline systems, compression and surface facilities, and has ownership interests in interstate pipelines serving the non-utility gas pipelinesMidwest, Ontario, and Northeast markets. The pipeline and storage businesses. assets are primarily supported by long-term, fixed-price revenue contracts.
Properties
Gas Storage and Pipelines results are discussed below:holds the following properties:
 2015 2014 2013
 (In millions)
Operating Revenues — Non-utility operations$243
 $203
 $132
Operation and maintenance58
 46
 25
Depreciation and amortization30
 34
 23
Taxes other than income5
 4
 3
Asset (gains) losses and impairments, net
 1
 
Operating Income150
 118
 81
Other (Income) and Deductions(29) (19) (36)
Income Tax Expense70
 53
 45
Net Income109
 84
 72
Net Income Attributable to Noncontrolling Interests2
 2
 2
Net Income Attributable to DTE Energy Company$107
 $82
 $70
Property Classification% OwnedDescriptionLocation
Pipelines
Appalachia Gathering System100%116-mile pipeline delivering Marcellus Shale gas to Texas Eastern Pipeline and Stonewall Gas Gathering systemPA and WV
Birdsboro Pipeline100%14-mile pipeline delivering gas supply to the Birdsboro Power PlantPA
Bluestone Pipeline100%64-mile pipeline delivering Marcellus Shale gas to Millennium Pipeline and Tennessee PipelinePA and NY
Michigan gathering systems100%590-mile pipeline system in northern MichiganMI
Millennium Pipeline26%269-mile pipeline serving markets in the NortheastNY
NEXUS Pipeline50%256-mile pipeline to transport Utica and Marcellus shale gas to Ohio, Michigan, and Ontario market centersOH and MI
Stonewall Gas Gathering55%68-mile pipeline connecting Appalachia Gathering System to Columbia PipelineWV
Susquehanna gathering system100%203-mile pipeline delivering Southwestern Energy's Marcellus Shale gas production to Bluestone PipelinePA
Tioga Gas Gathering100%3-mile pipeline delivering production gas to Dominion Transmission interconnectPA
Vector Pipeline40%348-mile pipeline connecting Chicago, Michigan, and Ontario market centersIL, IN, MI, and Ontario
Storage
Washington 10100%75 Bcf of storage capacityMI
Washington 2850%16 Bcf of storage capacityMI
Operating Revenues — Non-utility

The assets of these businesses are well integrated with other DTE Energy operations. Pursuant to an operating agreement, DTE Gas provides physical operations, increased $40 million in 2015 maintenance, and increased $71 million in 2014. The 2015 increase is due primarily to increased volumes ontechnical support for the Bluestone PipelineWashington 10 and Susquehanna28 storage facilities and for the Michigan gathering systems, partially offset by decreasedsystems.
Regulation
Gas Storage and Pipelines operates natural gas storage revenues duefacilities in Michigan as intrastate facilities regulated by the MPSC, and provides intrastate storage and related services pursuant to expiring contracts being replacedan MPSC-approved tariff. Gas Storage and Pipelines also provides interstate services in accordance with contracts at lower rates. The 2014 increase is due primarilyan Operating Statement on file with the FERC. Vector, Millennium, Birdsboro, and NEXUS Pipelines provide interstate transportation services in accordance with their FERC-approved tariffs. In addition, NEXUS and Vector are subject to increased volumes on the Bluestone Pipelineapplicable laws, rules, and additional segments placedregulations in service in the SusquehannaCanada. Gas Storage and Pipelines' gathering system. Storage revenue also increased due to weather favorability in early 2014, partially offset by lower market rates.
Operation and maintenance expense increased $12 million in 2015 and increased $21 million in 2014. The 2015 increase is due primarily to increased activity on the Bluestone and Susquehanna projects and increased gas storage operations expense. The 2014 increase is due primarily to increased activity on the Bluestone and Susquehanna projects and increased corporate overheads due to growth of this segment.
Depreciation and amortizationexpense decreased $4 million in 2015 and increased $11 million in 2014. The 2015 decrease is due primarily to a change in the estimated useful life of Susquehanna gatheringpipeline assets related to a contract extension in the fourth quarter of 2014, partially offset by additional Bluestone and Susquehanna projects placed in service. The 2014 increase is due primarilyare subject to the growthrules and regulations of the Bluestonevarious state utility commissions.
Strategy and Susquehanna projects.

33



Other (Income) and Deductions increased $10 million in 2015 and decreased $17 million in 2014. The 2015 increase is due primarily to increased earnings from pipeline investments. The 2014 decrease is due primarily to decreased earnings from a pipeline investment and increased intercompany interest expense. The earnings from the pipeline investment were negatively impacted in 2014 by a revenue deferral for depreciation collected in FERC-approved tariff rates in excess of depreciation expense.Competition
Outlook —Gas Storage and Pipelines expects to maintaincontinue its steady growth plan by expanding existing assets, acquiring and/or developing an asset portfolionew assets that are typically supported with multiplelong-term customer commitments. The focus will be on opportunities in the Midwest to Northeast region to supply natural gas to meet growing demand and displace less attractive supply from certain regions in North America. Much of the growth platforms through investment in new projectsdemand for natural gas is expected to occur in the eastern Canada and expansions.the northeast U.S. regions. Gas Storage and Pipelines will continuebelieves that the Vector, Millennium, and NEXUS Pipelines are well positioned to look for additionalprovide access routes and low-cost expansion options to these markets due to growth in production from the Marcellus/Utica Shales in Pennsylvania and West Virginia. Gas Storage and Pipelines has agreements with key producers that support its Bluestone Pipeline, Susquehanna gathering, Tioga gathering, AGS, and SGG businesses. Gas Storage and Pipelines is evaluating new pipeline and storage investment opportunities that could include additional pipeline and gathering expansions, laterals, compression, and other Marcellus/Utica shale midstream development or partnering opportunities.
Gas Storage and Pipelines has competition from other pipelines and storage and pipeline projects at favorable prices. The 2015 capacity expansionproviders. Operations are dependent upon a limited number of Bluestone Pipeline in Susquehanna County, Pennsylvania and Broome County, New York, is complete and included a second compressor facility and approximately six miles of additional pipeline loop to accommodate increased shipper demand. Planning and design activities are underway for Bluestone Pipeline's 2016 expansion. Additionally, the Susquehanna gathering system is being expanded to accommodate increased production. Despite recent pressure on producers from low commodity prices, DTE Energy believes its long-term agreement with Southwestern Energy Production Companycustomers, and the qualityloss of the natural gas reserves in the Marcellus region soundly positions Bluestone Pipeline and Susquehanna gathering system for future growth.
Progress continues on development activitiesany one or a few customers could have a material adverse effect on the NEXUS Pipeline, a transportation path to transport Appalachian Basin shale gas, including Uticaresults of Gas Storage and Marcellus shale gas, directly to consuming markets in northern Ohio, southeastern Michigan, and Dawn Ontario. DTE Energy owns a 50% partnership interest in the NEXUS Pipeline. A FERC application was filed in the fourth quarter of 2015 with an estimated in service date in the fourth quarter of 2017.Pipelines.
POWER AND INDUSTRIAL PROJECTS
The Description
Power and Industrial Projects segment is comprised primarily of projects that deliver energy and utility-type products and services to industrial, commercial, and institutional customers, produce reduced emissions fuel, and sell electricity and gas from renewable energy projects. This business segment provides services using project assets usually located on or near the customers' premises in the steel, automotive, pulp and paper, airport, chemical, and other industries as follows:
Industrial Energy Services
Steel and Petroleum Coke — Power and Industrial Projects results are discussed below:
 2015 2014 2013
 (In millions)
Operating Revenues — Non-utility operations$2,224
 $2,289
 $1,950
Fuel, purchased power, and gas — non-utility1,837
 1,913
 1,571
Gross Margin387
 376
 379
Operation and maintenance379
 368
 343
Depreciation and amortization78
 77
 72
Taxes other than income15
 15
 15
 Asset (gains) losses and impairments, net106
 (12) (4)
Operating Loss(191) (72) (47)
Other (Income) and Deductions(58) (66) (73)
Income Taxes     
Expense (Benefits)(49) (3) 8
Production Tax Credits(91) (97) (53)
 (140) (100) (45)
Net Income7
 94
 71
Net Income (Loss) Attributable to Noncontrolling Interests(9) 4
 5
Net Income Attributable to DTE Energy Company$16
 $90
 $66
Gross Margin increased $11 million in 2015 and decreased $3 million in 2014. The 2015 increase is primarily due to an $8 million increase in production atproduces metallurgical coke from a renewable power project, a $6 million increase in pricing at two landfill gas projects, a $6 million increase associatedcoke battery with a newly constructedcapacity of 1.0 million tons per year and has an investment in a second coke battery with a capacity of 1.2 million tons per year. Power and Industrial Projects also provides pulverized coal and petroleum coke to the steel, pulp and paper, and other industries.
On-Site Energy — Power and Industrial Projects provides power generation, steam production, chilled water production, wastewater treatment, and compressed air supply to industrial customers. Power and Industrial Projects also provides utility-type services using project assets usually located on or near the customers' premises in the on-site business,automotive, airport, chemical, and a $5 million increase in production in the REF business, partially offset by a $13 million decrease in product sales at the steel projects. The 2014 decrease is primarily due to a $13 million decrease in sales associated with project terminations in the on-site energy business, $12 million of higher start-up costs associated with new projects in the REF business, a $3 million decrease in lower pricing in the steel business, partially offset by a $19 million increase associated with new renewable powerother industries.


Renewable Energy
Wholesale Power and landfill gas projects,Renewables — Power and a $6 million increase due to the closing of the coal transportation business.

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Operation and maintenanceexpense increased $11 million in 2015 and increased $25 million in 2014. The 2015 increase is primarily due to costs associated with closure of the Shenango coke battery. The 2014 increase is primarily due to $16 million of higher maintenance and general administrative expenses in the steel business and $9 million of higher spending associated with the start-up of a renewable power project.
Depreciation and amortization expense increased by $1 million in 2015 and increased by $5 million in 2014. The 2014 increase is primarily due to $4 million associated with the start-up of a renewable power project.
Asset (gains) losses and impairments, net decreased by $118 million in 2015 and increased by $8 million in 2014. The 2015 decrease is due primarily to the closure of the Shenango coke battery and a renewable power project. The 2014 increase is due primarily to a gain associated with a sale of an on-site project in 2014 and an asset impairment recorded in 2013.
Other (Income) and Deductions decreased by $8 million in 2015 and decreased $7 million in 2014. The 2015 decrease is due primarily to charitable contributions, and the 2014 decrease is due primarily to lower equity earnings at various projects.
Income Taxes - Expense (Benefits) decreased by $46 million in 2015. The decrease is primarily due to the impact of the closure of the Shenango coke battery and a renewable power project.
Income Taxes - Production Tax Credits decreased by $6 million in 2015 and increased $44 million in 2014. The 2015 decrease is primarily due to the reduction ofIndustrial Projects holds ownership interests in, and operates, five renewable generating plants with a capacity of 217 MWs. The electric output is sold under long-term power purchase agreements.
Renewable Gas Recovery — Power and Industrial Projects has ownership interests in, and operates, twenty-three gas recovery sites in nine different states. The sites recover methane from landfills and agricultural businesses and convert the REF projects. The 2014 increase is due primarilygas to higher production volumes of refined coal that resultedgenerate electricity, replace fossil fuels in higher tax credits at REF projects.industrial and manufacturing operations, or refine to pipeline-quality gas, which can then be used as vehicle fuel.
Reduced Emissions Fuel
Net Income (Loss) Attributable to Noncontrolling Interests decreased by $13 million in 2015 and decreased by $1 million in 2014. The 2015 loss allocated to noncontrolling interests is primarily due to lease arrangements with investors at various REF facilities.
OutlookReduced Emissions Fuel Power and Industrial Projects has constructed and placed in service REF facilities at nineten sites including facilities located at sixseven third-party owned coal-fired power plants. DTE Energy has sold membership interests in fourfive of the facilities and entered into lease arrangements in twothree of the facilities. DTE Energy will continue to optimize these facilities by seeking investors or entering into lease arrangements for facilities operating at DTE Electric and other utility sites. DTE Energy is in the process of relocating underutilized facility equipment at an existing site to a new third-party owned coal-fired power plant. In addition, DTE Energy has entered into an agreement to operate an REF facility owned by an outside party located at a third-party owned coal-fired power plant. The facilities blend a proprietary additive with coal used in coal-fired power plants, resulting in reduced emissions of nitrogen oxide and mercury. Qualifying facilities are eligible to generate tax credits for ten years upon achieving certain criteria. The value of a tax credit is adjusted annually by an inflation factor published by the IRS. The value of the tax credit is reduced if the reference price of coal exceeds certain thresholds. The economic benefit of the REF facilities is dependent upon the generation of production tax credits.
DTE Energy expects decreased production levelsProperties and Other
The following are significant properties operated by Power and Industrial Projects:
Business AreasLocationService Type
Industrial Energy Services
Steel and Petroleum Coke
Pulverized Coal OperationsMIPulverized Coal
Coke ProductionMIMetallurgical Coke Supply
Other Investment in Coke Production and Petroleum CokeIN and MSMetallurgical Coke Supply and Pulverized Petroleum Coke
On-Site Energy
AutomotiveIN, MI, NY, and OHElectric Distribution, Chilled Water, Waste Water, Steam, Cooling Tower Water, Reverse Osmosis Water, Compressed Air, Mist, and Dust Collectors
AirportsMI and PAElectricity and Hot and Chilled Water
Chemical ManufacturingKY and OHElectricity, Steam, Natural Gas, Compressed Air, and Wastewater
Consumer ManufacturingOHElectricity, Steam, Wastewater, and Sewer
Business ParkPAElectricity
Hospital and UniversityCA and ILElectricity, Steam, and Chilled Water
Renewable Energy
Pulp and PaperALElectric Generation and Steam
RenewablesCA and MNElectric Generation
Renewable Gas RecoveryAZ, CA, MI, NC, NY, OH, TX, UT, and WIElectric Generation and Renewable Natural Gas
Reduced Emissions FuelMI, OH, IL, PA, TX, and WIREF Supply


 2018 2017 2016
 (In millions)
Production Tax Credits Generated (Allocated to DTE Energy)     
REF$178
 $144
 $103
Renewables7
 6
 8
Renewable Gas Recovery3
 3
 3
 $188
 $153
 $114
Regulation
Certain electric generating facilities within Power and Industrial Projects have market-based rate authority from the FERC to sell power. The facilities are subject to FERC reporting requirements and market behavior rules. Certain projects of metallurgical cokePower and pulverized coal suppliedIndustrial Projects are also subject to steel industry customers for 2016. A recent downturn in the steel industry in the United States will likely negatively impact the volumeapplicable laws, rules, and pricing of metallurgical coke sales for the upcoming year. See discussion of potential impairment riskregulations related to long-lived steel related assets in the Critical Accounting Estimates section. The segment has four renewable power generation facilities in operation. On-site energy services will continue to be delivered in accordance with the termsEPA, U.S. Department of long-term contracts. DTE Energy will continue to look for additional investment opportunitiesHomeland Security, DOE, and other energy projects at favorable prices.various state utility commissions.
Strategy and Competition
Power and Industrial Projects will continue to leverageleveraging its extensive energy-related operating experience and project management capability to develop additionaland grow its steel, on-site energy, and renewable energy businesses, and optimize the REF businesses. Power and Industrial Projects will also continue to pursue opportunities to provide asset management and operations services to third parties. There are limited competitors for Power and Industrial Projects' existing disparate businesses who provide similar products and services. Power and Industrial Projects' operations are dependent upon a limited number of customers, and the loss of any one or a few customers could have a material adverse effect on the results of Power and Industrial Projects.
Power and Industrial Projects anticipates building around its core strengths in the markets where it operates. In determining the markets in which to compete, Power and Industrial Projects examines closely the regulatory and competitive environment, new and pending legislation, the number of competitors, and its ability to achieve sustainable margins. Power and Industrial Projects plans to maximize the effectiveness of its related businesses as it expands.
Power and Industrial Projects intends to focus on the following areas for growth:
Providing operating services to owners of on-site industrial power plants;
Acquiring and developing renewable gas recovery facilities, renewable energy projects, to serveand other energy intensive industrial customers.projects.

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ENERGY TRADING
Description
Energy Trading focuses on physical and financial power and gas marketing and trading, structured transactions, enhancement of returns from its asset portfolio and optimization of contracted natural gas pipeline transportation, and storage positions. Energy Trading also provides natural gas, power, and related services which may include the management of associated storage and transportation contracts on the customers’ behalf and the supply or purchase of renewable energy credits to various customers. Energy Trading's customer base is predominantly utilities, local distribution companies, pipelines, producers and generators, and other marketing and trading companies. Energy Trading enters into derivative financial instruments as part of its marketing and hedging activities. These financial instruments are generally accounted for under the MTM method, which results in the recognition in earnings of unrealized gains and losses from changes in the fair value of the derivatives. Energy Trading utilizes forwards, futures, swaps, and option contracts to mitigate risk associated with marketing and trading activity, as well as for proprietary trading within defined risk guidelines. Energy Trading also provides commodity risk management services to the other businesses within DTE Energy.
Significant portions of the Energy Trading portfolio are economically hedged. Most financial instruments and physical power and natural gas contracts are deemed derivatives; whereas, natural gas inventory, contracts for pipeline transportation, renewable energy credits, and storage assets are not derivatives. As a result, this segment will experience earnings volatility as derivatives are marked-to-market without revaluing the underlying non-derivative contracts and assets. The business’ strategy is to economically manage the price risk of these underlying non-derivative contracts and assets with futures, forwards, swaps, and options. This results in gains and losses that are recognized in different interim and annual accounting periods.


Regulation
Energy Trading has market-based rate authority from the FERC to sell power and blanket authority from the FERC to sell natural gas at market prices. Energy Trading is subject to FERC reporting requirements and market behavior rules. Energy Trading is also subject to the applicable laws, rules, and regulations related to the CFTC, U.S. Department of Homeland Security, and DOE. In addition, Energy Trading is subject to applicable laws, rules, and regulations in Canada.
Strategy and Competition
DTE Energy's strategy for the Energy Trading business is to deliver value-added services to DTE Energy customers. DTE Energy seeks to manage this business in a manner complementary to the growth of DTE Energy's other business segments. Energy Trading focuses on physical marketing and the optimization of its portfolio of energy assets. The segment competes with electric and gas marketers, financial institutions, traders, utilities, and other energy providers. The Energy Trading business is dependent upon the availability of capital and an investment grade credit rating. DTE Energy believes it has ample available capital capacity to support Energy Trading activities. DTE Energy monitors its use of capital closely to ensure that its commitments do not exceed capacity. A material credit restriction would negatively impact Energy Trading's financial performance. Competitors with greater access to capital, or at a lower cost, may have a competitive advantage. DTE Energy has risk management and credit processes to monitor and mitigate risk.
CORPORATE AND OTHER
Description
Corporate and Other includes various holding company activities, holds certain non-utility debt, and holds energy-related investments.
ENVIRONMENTAL MATTERS
The Registrants are subject to extensive environmental regulation and expect to continue recovering environmental costs related to utility operations through rates charged to customers. The following table summarizes DTE Energy's, including DTE Electric's, estimated significant future environmental expenditures based upon current regulations. Pending or future reconsiderations of current regulations may impact the estimated expenditures summarized in the table below. The amounts reported in the table do not include any expenditures related to the EPA Clean Power Plan that has been stayed as discussed below. Actual costs to comply could vary substantially. Additional costs may result as the effects of various substances on the environment are studied and governmental regulations are developed and implemented.
 DTE Electric DTE Gas Non-utility Total
 (In millions)
Water$60
 $
 $
 $60
Contaminated and other sites10
 25
 
 35
Coal combustion residuals and effluent limitations guidelines515
 
 
 515
Estimated total future expenditures through 2025$585
 $25
 $
 $610
Estimated 2019 expenditures$30
 $15
 $
 $45
Estimated 2020 expenditures$60
 $5
 $
 $65
Water — The EPA finalized regulations on cooling water intake in August 2014. DTE Electric is conducting studies to determine the best technology for reducing the environmental impacts of the cooling water intake structures at each of its facilities. DTE Electric may be required to install technologies to reduce the impacts of the cooling water intakes.
Contaminated and Other Sites — Prior to the construction of major interstate natural gas pipelines, gas for heating and other uses was manufactured locally from processes involving coal, coke, or oil. The facilities, which produced gas, have been designated as MGP sites. DTE Gas owns, or previously owned, 14 such former MGP sites. DTE Electric owns, or previously owned, three former MGP sites. DTE Energy anticipates the cost amortization methodology approved by the MPSC for DTE Gas, which allows DTE Gas to amortize the MGP costs over a ten-year period beginning with the year subsequent to the year the MGP costs were incurred, will prevent environmental costs from having a material adverse effect on DTE Energy's operations. DTE Electric believes the likelihood of a material change to the accrued amount is remote based on current knowledge of the conditions at each site.


The Registrants are also in the process of cleaning up other sites where contamination is present as a result of historical and ongoing utility operations. These other sites include an engineered ash storage facility, electric distribution substations, gas pipelines, electric generating power plants, and underground and aboveground storage tank locations. Cleanup activities associated with these sites will be conducted over the next several years. Any significant change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for these sites and affect the Registrants' financial position and cash flows and the rates charged to their customers.
Coal Combustion Residuals and Effluent Limitations Guidelines — In April 2015, the EPA published a final rule for the disposal of coal combustion residuals, commonly known as coal ash. The rule became effective in October 2015. The rule is based on the continued listing of coal ash as a non-hazardous waste and relies on various self-implementation design and performance standards. DTE Electric owns and operates three permitted engineered coal ash storage facilities to dispose of coal ash from coal-fired power plants and operates a number of smaller impoundments at its power plants. At certain facilities, the rule requires the installation of monitoring wells, compliance with groundwater standards, and the closure of basins at the end of the useful life of the associated power plant. At other facilities, the rule requires ash laden waters be moved from earthen basins to steel and concrete tanks. In 2018, DTE Electric updated its estimated expenditures to remediate accordingly. On October 12, 2018, a D.C. District Court decision became effective that may affect the timing of closure of coal ash impoundments that are not lined with an engineered liner system. In 2019, the EPA is expected to affirmatively undertake rulemaking to implement the D.C. District Court's decision that will determine any changes to DTE Electric's plans in the operations and closure of coal ash impoundments.
In November 2015, the EPA finalized effluent limitations guidelines for the steam electric power generating industry which requires additional controls to be installed between 2018 and 2023. The initial costs to comply with this rule are under development and estimates are included in the Coal Combustion Residual and Effluent Limitations Guidelines amount in the above table.
On April 12, 2017, the EPA granted a petition for reconsideration of the ELG Rule. The EPA also signed an administrative stay of the ELG Rule’s compliance deadlines for fly ash transport water, bottom ash transport water, and flue gas desulfurization (FGD) wastewater, among others. On June 6, 2017, the EPA published in the Federal Register a proposed rule to postpone certain applicable deadlines within the ELG rule. The final rule was published on September 18, 2017. The final rule nullified the administrative stay but also extended the earliest compliance deadlines for the FGD wastewater and bottom ash transport water until November 1, 2020 in order for the EPA to propose and finalize a new ruling. The ELG compliance requirements and final deadlines for bottom ash transport water and FGD wastewater, and total ELG related compliance costs will not be known until the EPA completes its reconsideration of the ELG Rule.
Air — DTE Electric is subject to the EPA ozone and fine particulate transport, and acid rain regulations that limit power plant emissions of SO2 and NOX. The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to emission controls on fossil-fueled power plants to reduce SO2, NOX, mercury, and other emissions. These rulemakings could require additional controls for SO2, NOX, and other hazardous air pollutants over the next few years. DTE Electric does not anticipate additional capital expenditures to comply with air pollution requirements through 2025, pending the results of future rulemakings.
The EPA has implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, the EPA has finalized performance standards for emissions of carbon dioxide from new and existing fossil-fuel EGUs. In February 2016, the U.S. Supreme Court granted petitioners' requests for a stay of the carbon rules for existing EGUs (also known as the EPA Clean Power Plan) pending final review by the courts. The Clean Power Plan has no legal effect while the stay is in place. In October 2017, the EPA issued a proposal to repeal the Clean Power Plan, and in August 2018 the EPA issued its proposed Affordable Clean Energy rule to replace the Clean Power Plan. In addition, in December 2018, the EPA issued proposed revisions to the carbon dioxide standards for new, modified or reconstructed fossil-fuel fired EGUs. The carbon dioxide standard for new sources are not expected to have a material impact on DTE Electric, since DTE Electric has no plans to build new coal-fired generation and any potential new gas generation will be able to comply with the standards. These proposed rules do not impact DTE Energy's goal to reduce carbon emissions 30% by the early 2020s, 45% by 2030, 75% by 2040, and more than 80% by 2050.


Pending or future legislation or other regulatory actions could have a material impact on DTE Electric's operations and financial position and the rates charged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. DTE Electric would seek to recover these incremental costs through increased rates charged to its utility customers, as authorized by the MPSC.
See Management’s Discussion and Analysis in Item 7 of this Report and Notes 8, 9, and 18 to the Consolidated Financial Statements in Item 8 of this Report, "Asset Retirement Obligations," "Regulatory Matters," and "Commitments and Contingencies."
EMPLOYEES
DTE Energy and its subsidiaries had approximately 10,600 employees as of December 31, 2018, of which approximately 5,200 were represented by unions. DTE Electric had approximately 4,900 employees as of December 31, 2018, of which approximately 2,800 were represented by unions. There are several bargaining units for DTE Energy subsidiaries' represented employees. The majority of represented employees for both DTE Energy and DTE Electric are under contracts that expire in 2020 and 2021.

Item 1A. Risk Factors
There are various risks associated with the operations of the Registrants' utility businesses and DTE Energy's non-utility businesses. To provide a framework to understand the operating environment of the Registrants, below is a brief explanation of the more significant risks associated with their businesses. Although the Registrants have tried to identify and discuss key risk factors, others could emerge in the future. Each of the following risks could affect performance.
The Registrants are subject to rate regulation. Electric and gas rates for the utilities are set by the MPSC and the FERC and cannot be changed without regulatory authorization. The Registrants may be negatively impacted by new regulations or interpretations by the MPSC, the FERC, or other regulatory bodies. The Registrants' ability to recover costs may be impacted by the time lag between the incurrence of costs and the recovery of the costs in customers' rates. Regulators also may decide to disallow recovery of certain costs in customers' rates if they determine that those costs do not meet the standards for recovery under current governing laws and regulations. Regulators may also disagree with the Registrants' rate calculations under the various mechanisms that are intended to mitigate the risk to their utilities related to certain aspects of the business. If the Registrants cannot agree with regulators on an appropriate reconciliation of those mechanisms, it may impact the Registrants' ability to recover certain costs through customer rates. Regulators may also decide to eliminate these mechanisms in future rate cases, which may make it more difficult for the Registrants to recover their costs in the rates charged to customers. The Registrants cannot predict what rates the MPSC will authorize in future rate cases. New legislation, regulations, or interpretations could change how the business operates, impact the Registrants' ability to recover costs through rates or the timing of such recovery, or require the Registrants to incur additional expenses.
Changes to Michigan's electric retail access program could negatively impact the Registrants' financial performance. The State of Michigan currently experiences a hybrid market, where the MPSC continues to regulate electric rates for DTE Electric customers, while alternative electric suppliers charge market-based rates. MPSC rate orders, and energy legislation enacted by the State of Michigan, have placed a 10% cap on the total potential retail access migration. However, even with the legislated 10% cap on participation, there continues to be legislative and financial risk associated with the electric retail access program. Electric retail access migration is sensitive to market price and full service electric price changes. The Registrants are required under current regulation to provide full service to retail access customers that choose to return, potentially resulting in the need for additional generating capacity.


The Registrants' electric distribution system and DTE Energy's gas distribution system are subject to risks from their operation, which could reduce revenues, increase expenses, and have a material adverse effect on their business, financial position, and results of operations. The Registrants' electric distribution and DTE Energy’s gas distribution systems are subject to many operational risks. These operational systems and infrastructure have been in service for many years. Equipment, even when maintained in accordance with good utility practices, is subject to operational failure, including events that are beyond the Registrants' control, and could require significant operation and maintenance expense or capital expenditures to operate efficiently. Because the Registrants’ distribution systems are interconnected with those of third parties, the operation of the Registrants’ systems could be adversely affected by unexpected or uncontrollable events occurring on the systems of such third parties.
DTE Energy's non-utility businesses may not perform to its expectations. DTE Energy relies on non-utility operations for an increasing portion of earnings. If DTE Energy's current and contemplated non-utility investments do not perform at expected levels, DTE Energy could experience diminished earnings and a corresponding decline in shareholder value.
DTE Energy relies on cash flows from subsidiaries. DTE Energy is a holding company. Cash flows from the utility and non-utility subsidiaries are required to pay interest expenses and dividends on DTE Energy debt and securities. Should a major subsidiary not be able to pay dividends or transfer cash flows to DTE Energy, its ability to pay interest and dividends would be restricted.
The Registrants' businesses have safety risks. The Registrants' electric distribution system, power plants, renewable energy equipment, and other facilities, and DTE Energy's gas distribution system, gas infrastructure, and other facilities, could be involved in incidents that result in injury, death, or property loss to employees, customers, third parties, or the public. Although the Registrants have insurance coverage for many potential incidents, depending upon the nature and severity of any incident, they could experience financial loss, damage to their reputation, and negative consequences from regulatory agencies or other public authorities.
Environmental laws and liability may be costly. The Registrants are subject to, and affected by, numerous environmental regulations. These regulations govern air emissions, water quality, wastewater discharge, and disposal of solid and hazardous waste. Compliance with these regulations can significantly increase capital spending, operating expenses, and plant down times, and can negatively affect the affordability of the rates charged to customers.
Uncertainty around future environmental regulations creates difficulty planning long-term capital projects in the Registrants' generation fleet and, for DTE Energy's gas distribution businesses. These laws and regulations require the Registrants to seek a variety of environmental licenses, permits, inspections, and other regulatory approvals. The Registrants could be required to install expensive pollution control measures or limit or cease activities, including the retirement of certain generating plants, based on these regulations. Additionally, the Registrants may become a responsible party for environmental cleanup at sites identified by a regulatory body. The Registrants cannot predict with certainty the amount and timing of future expenditures related to environmental matters because of the difficulty of estimating cleanup costs. There is also uncertainty in quantifying liabilities under environmental laws that impose joint and several liability on potentially responsible parties.
The Registrants may also incur liabilities as a result of potential future requirements to address climate change issues. Proposals for voluntary initiatives and mandatory controls are being discussed both in the United States and worldwide to reduce GHGs such as carbon dioxide, a by-product of burning fossil fuels. If increased regulations of GHG emissions are implemented, the operations of DTE Electric's fossil-fueled generation assets may be significantly impacted. Since there can be no assurances that environmental costs may be recovered through the regulatory process, the Registrants' financial performance may be negatively impacted as a result of environmental matters.
For DTE Energy, future environmental regulation of natural gas extraction techniques, including hydraulic fracturing, being discussed both at the United States federal level and by some states may affect the profitability of natural gas extraction businesses which could affect demand for, and profitability of, DTE Energy's gas transportation businesses.
Threats of cyber incidents, physical security, and terrorism could affect the Registrants' business. Issues may threaten the Registrants such as cyber incidents, physical security, or terrorism that may disrupt the Registrants' operations, and could harm the Registrants' operating results.


Information security risks have increased in recent years as a result of the proliferation of new technologies and the increased sophistication and frequency of cyberattacks, and data security breaches. The Registrants' industry requires the continued operation of sophisticated information and control technology systems and network infrastructure. Despite implementation of security measures, all of the Registrants' technology systems are vulnerable to disability or failures due to cyber incidents, physical security threats, acts of war or terrorism, and other causes, as well as loss of operational control of the Registrants' electric generation and distribution assets and, DTE Energy's gas distribution assets. If the Registrants' information technology systems were to fail and they were unable to recover in a timely way, the Registrants may be unable to fulfill critical business functions, which could have a material adverse effect on the Registrants' business, operating results, and financial condition.
Suppliers, vendors, contractors, and information technology providers have access to systems that support the Registrants’ operations and maintain customer and employee data.  A breach of these third-party systems could adversely affect the business as if it was a breach of our own system.  Also, because the Registrants’ generation and distribution systems are part of an interconnected system, a disruption caused by a cyber incident at another utility, electric generator, system operator, or commodity supplier could also adversely affect the Registrants’ businesses, operating results, and financial condition.
In addition, the Registrants' generation plants and electrical distribution facilities, and DTE Energy's gas pipeline and storage facilities, in particular, may be targets of physical security threats or terrorist activities that could disrupt the Registrants' ability to produce or distribute some portion of their products. The Registrants have increased security as a result of past events and may be required by regulators or by the future threat environment to make investments in security that the Registrants cannot currently predict.
Failure to maintain the security of personally identifiable information could adversely affect the Registrants. In connection with the Registrants' businesses, they collect and retain personally identifiable information of their customers, shareholders, and employees. Customers, shareholders, and employees expect that the Registrants will adequately protect their personal information. The regulatory environment surrounding information security and privacy is increasingly demanding. A significant theft, loss, or fraudulent use of customer, shareholder, employee, or Registrant data by cybercrime or otherwise, could adversely impact the Registrants' reputation, and could result in significant costs, fines, and litigation.
Construction and capital improvements to the Registrants' power facilities, DTE Energy's distribution systems and its Gas Storage and Pipelines business subject them to risk. The Registrants are managing ongoing, and planning future, significant construction and capital improvement projects at the Registrants' multiple power generation and distribution facilities, at DTE Energy's gas distribution system, and at DTE Energy's Gas Storage and Pipelines business. Many factors that could cause delays or increased prices for these complex projects are beyond the Registrants' control, including the cost of materials and labor, subcontractor performance, timing and issuance of necessary permits or approvals (including required certificates from regulatory agencies), construction disputes, impediments to acquiring rights-of-way or land rights on a timely basis and on acceptable terms, cost overruns, and weather conditions. Failure to complete these projects on schedule and on budget for any reason could adversely affect the Registrants' financial performance, operations, or expected investment returns at the affected facilities, businesses and development projects.
Operation of a nuclear facility subjects the Registrants to risk. Ownership of an operating nuclear generating plant subjects the Registrants to significant additional risks. These risks include, among others, plant security, environmental regulation and remediation, changes in federal nuclear regulation, increased capital expenditures to meet industry requirements, and operational factors that can significantly impact the performance and cost of operating a nuclear facility compared to other generation options. Insurance maintained by the Registrants for various nuclear-related risks may not be sufficient to cover the Registrants' costs in the event of an accident or business interruption at the nuclear generating plant, which may affect the Registrants' financial performance. In addition, the Registrants' nuclear decommissioning trust fund, to finance the decommissioning of the nuclear generating plant, may not be sufficient to fund the cost of decommissioning. A decline in market value of assets held in decommissioning trust funds due to poor investment performance or other factors may increase the funding requirements for these obligations. Any increase in funding requirements may have a material impact on the Registrants’ liquidity, financial position, or results of operations.


The supply and/or price of energy commodities and/or related services may impact the Registrants' financial results. The Registrants are dependent on coal for much of their electrical generating capacity as well as uranium for their nuclear operations. DTE Energy's access to natural gas supplies is critical to ensure reliability of service for utility gas customers. DTE Energy's non-utility businesses are also dependent upon supplies and prices of energy commodities and services. Price fluctuations, fuel supply disruptions, and changes in transportation costs, could have a negative impact on the amounts DTE Electric charges utility customers for electricity and DTE Gas charges utility customers for gas, and on the profitability of DTE Energy's non-utility businesses. The Registrants' hedging strategies and regulatory recovery mechanisms may be insufficient to mitigate the negative fluctuations in commodity supply prices in their utility and, for DTE Energy, non-utility businesses, and the Registrants' financial performance may therefore be negatively impacted by price fluctuations. The price of energy also impacts the market for DTE Energy's non-utility businesses that compete with utilities and alternative electric suppliers.
The supply and/or price of other industrial raw and finished inputs and/or related services may impact the Registrants' financial results. The Registrants are dependent on supplies of certain commodities, such as copper and limestone, among others, and industrial materials, and services in order to maintain day-to-day operations and maintenance of their facilities. Price fluctuations, or supply interruptions for these commodities and other items, could have a negative impact on the amounts charged to customers for the Registrants' utility products and, for DTE Energy, on the profitability of the non-utility businesses.
Emerging technologies may have a material adverse effect on the Registrants. Advances in technology that produce power or reduce power consumption include cost-effective renewable energy technologies, distributed generation, energy waste reduction technologies, and energy storage devices. Such developments may impact the price of energy, may affect energy deliveries as customer-owned generation becomes more cost-effective, may require further improvements to our distribution systems to address changing load demands, and could make portions of our electric system power supply and/or distribution facilities obsolete prior to the end of their useful lives. Such technologies could also result in further declines in commodity prices or demand for delivered energy. Each of these factors could materially affect the Registrants’ results of operations, cash flows, or financial position.
Adverse changes in the Registrants' credit ratings may negatively affect them. Regional and national economic conditions, increased scrutiny of the energy industry and regulatory changes, as well as changes in the Registrants' economic performance, could result in credit agencies reexamining their credit ratings. While credit ratings reflect the opinions of the credit agencies issuing such ratings and may not necessarily reflect actual performance, a downgrade in the Registrants' credit ratings below investment grade could restrict or discontinue their ability to access capital markets and could result in an increase in their borrowing costs, a reduced level of capital expenditures, and could impact future earnings and cash flows. In addition, a reduction in the Registrants' credit ratings may require them to post collateral related to various physical or financially settled contracts for the purchase of energy-related commodities, products, and services, which could impact their liquidity.
Poor investment performance of pension and other postretirement benefit plan assets and other factors impacting benefit plan costs could unfavorably impact the Registrants' liquidity and results of operations. The Registrants' costs of providing non-contributory defined benefit pension plans and other postretirement benefit plans are dependent upon a number of factors, such as the rates of return on plan assets, the level of interest rates used to measure the required minimum funding levels of the plans, future government regulation, and the Registrants' required or voluntary contributions made to the plans. The performance of the debt and equity markets affects the value of assets that are held in trust to satisfy future obligations under the Registrants' plans. The Registrants have significant benefit obligations and hold significant assets in trust to satisfy these obligations. These assets are subject to market fluctuations and will yield uncertain returns, which may fall below the Registrants' projected return rates. A decline in the market value of the pension and other postretirement benefit plan assets will increase the funding requirements under the pension and other postretirement benefit plans if the actual asset returns do not recover these declines in the foreseeable future. Additionally, the pension and other postretirement benefit plan liabilities are sensitive to changes in interest rates. If interest rates decrease, the liabilities increase, resulting in increasing benefit expense and funding requirements. Also, if future increases in pension and other postretirement benefit costs as a result of reduced plan assets are not recoverable from the Registrants' utility customers, the results of operations and financial position of the Registrants could be negatively affected. Without sustained growth in the plan investments over time to increase the value of plan assets, the Registrants could be required to fund these plans with significant amounts of cash. Such cash funding obligations could have a material impact on the Registrants' cash flows, financial position, or results of operations.


The Registrants' ability to access capital markets is important. The Registrants' ability to access capital markets is important to operate their businesses and to fund capital investments. Turmoil in credit markets may constrain the Registrants' ability, as well as the ability of their subsidiaries, to issue new debt, including commercial paper, and refinance existing debt at reasonable interest rates. In addition, the level of borrowing by other energy companies, and the market as a whole, could limit the Registrants' access to capital markets. The Registrants' long-term revolving credit facilities do not expire until 2022, but the Registrants regularly access capital markets to refinance existing debt or fund new projects at the Registrants' utilities and DTE Energy's non-utility businesses, and the Registrants cannot predict the pricing or demand for those future transactions.
DTE Energy's participation in energy trading markets subjects it to risk. Events in the energy trading industry have increased the level of scrutiny on the energy trading business and the energy industry as a whole. In certain situations, DTE Energy may be required to post collateral to support trading operations, which could be substantial. If access to liquidity to support trading activities is curtailed, DTE Energy could experience decreased earnings potential and cash flows. Energy trading activities take place in volatile markets and expose DTE Energy to risks related to commodity price movements, deviations in weather, and other related risks. DTE Energy's trading business routinely has speculative trading positions in the market, within strict policy guidelines DTE Energy sets, resulting from the management of DTE Energy's business portfolio. To the extent speculative trading positions exist, fluctuating commodity prices can improve or diminish DTE Energy's financial results and financial position. DTE Energy manages its exposure by establishing and enforcing strict risk limits and risk management procedures. During periods of extreme volatility, these risk limits and risk management procedures may not work as planned and cannot eliminate all risks associated with these activities.
Weather significantly affects operations. At both utilities, deviations from normal hot and cold weather conditions affect the Registrants' earnings and cash flows. Mild temperatures can result in decreased utilization of the Registrants' assets, lowering income and cash flows. At DTE Electric, ice storms, tornadoes, or high winds can damage the electric distribution system infrastructure and power generation facilities and require it to perform emergency repairs and incur material unplanned expenses. The expenses of storm restoration efforts may not be fully recoverable through the regulatory process. DTE Gas can experience higher than anticipated expenses from emergency repairs on its gas distribution infrastructure required as a result of weather related issues.
Unplanned power plant outages may be costly. Unforeseen maintenance may be required to safely produce electricity or comply with environmental regulations. As a result of unforeseen maintenance, the Registrants may be required to make spot market purchases of electricity that exceed the costs of generation. The Registrants' financial performance may be negatively affected if unable to recover such increased costs.
Regional, national, and international economic conditions can have an unfavorable impact on the Registrants. The Registrants' utility and DTE Energy's non-utility businesses follow the economic cycles of the customers they serve and credit risk of counterparties they do business with. Should the financial conditions of some of DTE Energy's significant customers deteriorate as a result of regional, national or international economic conditions, reduced volumes of electricity and gas, and demand for energy services DTE Energy supplies, collections of accounts receivable, reductions in federal and state energy assistance funding, and potentially higher levels of lost gas or stolen gas and electricity could result in decreased earnings and cash flows.
Renewable portfolio standards and energy waste reduction programs may affect the Registrants' business. The Registrants are subject to existing Michigan, and potential future, federal legislation and regulation requiring them to secure sources of renewable energy. The Registrants have complied with the existing federal and state legislation, but do not know what requirements may be added by federal or state legislation in the future. In addition, the Registrants expect to comply with new Michigan legislation increasing the percentage of power required to be provided by renewable energy sources. The Registrants cannot predict the financial impact or costs associated with complying with potential future legislation and regulations. Compliance with these requirements can significantly increase capital expenditures and operating expenses and can negatively affect the affordability of the rates charged to customers.
The Registrants are also required by Michigan legislation to implement energy waste reduction measures and provide energy waste reduction customer awareness and education programs. These requirements necessitate expenditures, and implementation of these programs creates the risk of reducing the Registrants' revenues as customers decrease their energy usage. The Registrants cannot predict how these programs will impact their business and future operating results.


Failure to attract and retain key executive officers and other skilled professional and technical employees could have an adverse effect on the Registrants operations. The Registrants' businesses are dependent on their ability to attract and retain skilled employees. Competition for skilled employees in some areas is high, and the inability to attract and retain these employees could adversely affect the Registrants' business and future operating results. In addition, the Registrants have an aging utility workforce, and the failure of a successful transfer of knowledge and expertise could negatively impact their operations.
A work interruption may adversely affect the Registrants. There are several bargaining units for DTE Energy's approximately 5,200 and DTE Electric's approximately 2,800 represented employees. The majority of represented employees are under contracts that expire in 2020 and 2021. A union choosing to strike would have an impact on the Registrants' businesses. The Registrants are unable to predict the effect a work stoppage would have on their costs of operations and financial performance.
DTE Energy's ability to utilize production tax credits may be limited. To reduce U.S. dependence on imported oil, the Internal Revenue Code provides production tax credits as an incentive for taxpayers to produce fuels and electricity from alternative sources. DTE Energy generated production tax credits from coke production, renewable gas recovery, reduced emission fuel, and gas production operations, and for the Registrants, renewable energy generation. If the Registrants' production tax credits were disallowed in whole or in part as a result of an IRS audit or changes in tax law, there could be additional tax liabilities owed for previously recognized tax credits that could significantly impact the Registrants' earnings and cash flows.
If DTE Energy's goodwill becomes impaired, it may be required to record a charge to earnings. DTE Energy annually reviews the carrying value of goodwill associated with acquisitions it has made for impairment. Factors that may be considered for purposes of this analysis include any change in circumstances indicating that the carrying value of DTE Energy goodwill may not be recoverable, such as a decline in stock price and market capitalization, future cash flows, and slower growth rates in the industry. DTE Energy cannot predict the timing, strength, or duration of any economic slowdown or subsequent recovery, worldwide or in the economy or markets in which it operates; however, when events or changes in circumstances indicate that the carrying value of these assets may not be recoverable, DTE Energy may take a non-cash impairment charge, which could potentially materially impact DTE Energy's results of operations and financial position.
The Registrants may not be fully covered by insurance. The Registrants have a comprehensive insurance program in place to provide coverage for various types of risks, including catastrophic damage as a result of severe weather or other natural disasters, war, terrorism, or a combination of other significant unforeseen events that could impact the Registrants' operations. Economic losses might not be covered in full by insurance, or the Registrants' insurers may be unable to meet contractual obligations.

Item 1B. Unresolved Staff Comments
None.



Item 3. Legal Proceedings
In March 2018, the Trenton Channel Power Plant experienced exceedances of its mercury emission limits. The exceedances were reported to the EPA and the MDEQ. On September 12, 2018, the EPA issued a NOV. DTE Electric is currently working with the EPA to address the NOV.  At this time, DTE Electric cannot predict the impact of the NOV.
For more information on legal proceedings and matters related to the Registrants, see Notes 9 and 18 to the Consolidated Financial Statements in Item 8 of this Report, "Regulatory Matters" and "Commitments and Contingencies," respectively.

Item 4. Mine Safety Disclosures
Not applicable.


Part II
Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters, and Issuer Purchases of Equity Securities
DTE Energy common stock is listed under the ticker symbol "DTE" on the New York Stock Exchange, which is the principal market for such stock.
At December 31, 2018, there were 181,925,281 shares of DTE Energy common stock outstanding. These shares were held by a total of 51,338 shareholders of record.
All of the 138,632,234 issued and outstanding shares of DTE Electric common stock, par value $10 per share, are owned by DTE Energy, and constitute 100% of the voting securities of DTE Electric. Therefore, no market exists for DTE Electric's common stock.
For information on DTE Energy dividend restrictions, see Note 16 to the Consolidated Financial Statements in Item 8 of this Report, "Short-Term Credit Arrangements and Borrowings."
All of DTE Energy's equity compensation plans that provide for the annual awarding of stock-based compensation have been approved by shareholders. For additional detail, see Note 21 to the Consolidated Financial Statements in Item 8 of this Report, "Stock-Based Compensation."
See the following table for information as of December 31, 2018:
 Number of Securities to be Issued Upon Exercise of Outstanding Options Weighted-Average Exercise Price of Outstanding Options Number of Securities Remaining Available for Future Issuance Under Equity Compensation Plans
Plans approved by shareholders52,100
 $43.30
 2,897,674
UNREGISTERED SALES OF DTE ENERGY EQUITY SECURITIES AND USE OF PROCEEDS
Purchases of DTE Energy Equity Securities by the Issuer and Affiliated Purchasers
The following table provides information about DTE Energy's purchases of equity securities that are registered by DTE Energy pursuant to Section 12 of the Exchange Act of 1934 for the quarter ended December 31, 2018:
 
Number of Shares Purchased(a)
 
Average Price
Paid per Share
(a)
 Number of Shares Purchased as Part of Publicly Announced
Plans or Programs
 Average Price Paid per Share Maximum Dollar
Value that May
Yet Be Purchased Under the Plans or Programs
10/01/2018 — 10/31/2018143
 $110.14
 
 
 
11/01/2018 — 11/30/2018
 $
 
 
 
12/01/2018 — 12/31/2018
 $
 
 
 
Total143
  
 
  
  

(a)Represents shares of DTE Energy common stock withheld to satisfy income tax obligations upon the vesting of restricted stock based on the price in effect at the grant date.


COMPARISON OF CUMULATIVE FIVE YEAR TOTAL RETURN
Total Return to DTE Energy Shareholders
(Includes reinvestment of dividends)
  Annual Return Percentage
Year Ended December 31,
Company/Index 2014 2015 2016 2017 2018
DTE Energy Company 34.61
 (3.77) 26.93
 14.59
 4.19
S&P 500 Index 13.69
 1.38
 11.95
 21.82
 (4.39)
S&P 500 Multi-Utilities Index 28.94
 (1.73) 18.56
 12.09
 1.77
  Indexed Returns
Year Ended December 31,
  Base Period          
Company/Index 2013 2014 2015 2016 2017 2018
DTE Energy Company 100.00
 134.61
 129.54
 164.41
 188.40
 196.30
S&P 500 Index 100.00
 113.69
 115.26
 129.04
 157.19
 150.29
S&P 500 Multi-Utilities Index 100.00
 128.94
 126.71
 150.22
 168.38
 171.35
dteenergy20_chart-06124a04.jpg



Item 6. Selected Financial Data
The following selected financial data of DTE Energy should be read in conjunction with the accompanying Management’s Discussion and Analysis in Item 7 of this Report and Combined Notes to Consolidated Financial Statements in Item 8 of this Report. This information has been omitted for DTE Electric per General Instruction I (2) (a) of Form 10-K for wholly-owned subsidiaries (reduced disclosure format).
 2018 2017 2016 2015 2014
 (In millions, except per share amounts)
Operating Revenues$14,212
 $12,607
 $10,630
 $10,337
 $12,301
Net Income Attributable to DTE Energy Company(a)
$1,120
 $1,134
 $868
 $727
 $905
Diluted Earnings Per Common Share$6.17
 $6.32
 $4.83
 $4.05
 $5.10
Financial Information         
Dividends declared per share of common stock$3.60
 $3.36
 $3.06
 $2.84
 $2.69
Total Assets$36,288
 $33,767
 $32,041
 $28,662
 $27,827
Long-Term Debt(b)
$12,134
 $12,185
 $11,269
 $8,760
 $8,271
Shareholders’ equity$10,237
 $9,512
 $9,011
 $8,772
 $8,327

(a)The 2017 results include a $105 million net income tax benefit related to the enactment of the TCJA.
(b)Long-Term Debt includes Capital lease obligations and excludes debt due within one year.

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations
The following combined discussion is separately filed by DTE Energy and DTE Electric. However, DTE Electric does not make any representations as to information related solely to DTE Energy or the subsidiaries of DTE Energy other than itself.
EXECUTIVE OVERVIEW
DTE Energy is a diversified energy company with 2018 Operating Revenues of approximately $14.2 billion and Total Assets of approximately $36.3 billion. DTE Energy is the parent company of DTE Electric and DTE Gas, regulated electric and natural gas utilities engaged primarily in the business of providing electricity and natural gas sales, distribution, and storage services throughout Michigan. DTE Energy operates three energy-related non-utility segments with operations throughout the United States.
The following table summarizes DTE Energy's financial results:
 Years Ended December 31,
 2018 2017 2016
 (In millions, except per share amounts)
Net Income Attributable to DTE Energy Company$1,120
 $1,134
 $868
Diluted Earnings per Common Share$6.17
 $6.32
 $4.83
The decrease in 2018 Net Income Attributable to DTE Energy Company was primarily due to lower earnings in the Gas Storage and Pipelines, Energy Trading, and Corporate and Other segments, partially offset by higher earnings in the Electric, Gas, and Power and Industrial Projects segments. The 2018 decrease was partially attributable to true-up adjustments for the remeasurement of deferred taxes of $21 million as the adjustments increased Income Tax Expense, of which $17 million was attributable to the regulated utilities and increased Regulatory liabilities. The increase in 2017 Net Income Attributable to DTE Energy Company was primarily due to higher earnings in the Gas Storage and Pipelines, Energy Trading, and Power and Industrial Projects segments, partially offset by lower earnings in the Corporate and Other segment. The 2017 increase was also due to $105 million of net income tax benefit related to the enactment of the TCJA.
Please see detailed explanations of segment performance in the following "Results of Operations" section.
DTE Energy's strategy is to achieve long-term earnings growth, a strong balance sheet, and an attractive dividend yield.


DTE Energy's utilities are investing capital to improve customer reliability through investments in base infrastructure and new generation, and to comply with environmental requirements. DTE Energy expects that planned significant capital investments will result in earnings growth. DTE Energy is focused on executing plans to achieve operational excellence and customer satisfaction with a focus on customer affordability. DTE Energy operates in a constructive regulatory environment and has solid relationships with its regulators.
In May 2017, DTE Energy announced its plan to reduce carbon emissions. This goal will be attained by cutting carbon emissions 30% by the early 2020s, 45% by 2030, 75% by 2040, and more than 80% by 2050. To achieve this reduction, DTE Energy will transition away from coal-powered sources and incorporate more renewable energy, energy waste reduction projects, demand response, and natural gas fueled generation. DTE Energy has already begun the transition in the way it produces power through the continued retirement of its aging coal-fired plants. In May 2018, DTE Energy announced its plans to accelerate its clean energy initiatives by targeting at least a 50% clean energy goal by 2030 to be achieved through a combination of investments in renewable energy and energy waste reduction projects. Refer to the "Capital Investments" section below for further discussion.
DTE Energy has significant investments in non-utility businesses. DTE Energy employs disciplined investment criteria when assessing growth opportunities that leverage its assets, skills, and expertise, and provides diversity in earnings and geography. Specifically, DTE Energy invests in targeted energy markets with attractive competitive dynamics where meaningful scale is in alignment with its risk profile. DTE Energy expects growth opportunities in the Gas Storage and Pipelines and Power and Industrial Projects segments.
A key priority for DTE Energy is to maintain a strong balance sheet which facilitates access to capital markets and reasonably priced short-term and long-term financing. Near-term growth will be funded through internally generated cash flows and the issuance of debt and equity. DTE Energy has an enterprise risk management program that, among other things, is designed to monitor and manage exposure to earnings and cash flow volatility related to commodity price changes, interest rates, and counterparty credit risk.
CAPITAL INVESTMENTS
DTE Energy's utility businesses require significant capital investments to maintain and improve the electric generation and electric and natural gas distribution infrastructure and to comply with environmental regulations and renewable energy requirements.
DTE Electric's capital investments over the 2019-2023 period are estimated at $11.3 billion comprised of $4.0 billion for capital replacements and other projects, $4.6 billion for distribution infrastructure, and $2.7 billion for new generation. DTE Electric has retired four coal-fired generation units at the Trenton Channel, River Rouge, and St Clair facilities and has announced plans to retire its remaining thirteen coal-fired generating units. Seven of these coal-fired generating units will be retired through 2023 at the Trenton Channel, River Rouge, and St. Clair facilities. The remaining coal-fired generating units at the Belle River and Monroe facilities are expected to be retired by 2040. The retired facilities will be replaced with renewables, energy waste reduction, demand response, and natural gas fueled generation. In April 2018, DTE Electric received approval from the MPSC to build a natural gas fueled combined cycle generation facility to provide approximately 1,100 megawatts of energy beginning in 2022. In August 2018, DTE Electric began construction on its natural gas fueled combined cycle generation facility. In March 2018, DTE Electric filed its 2018 Renewable Energy Plan with the MPSC proposing approximately 1,000 additional megawatts of energy from new wind and solar projects to be completed by 2022. The MPSC had previously approved 300 of the 1,000 additional megawatts for wind projects in an MPSC order received in September 2016. In January 2018, DTE Electric filed with the MPSC its five-year distribution operations investment and maintenance plan to improve system reliability. DTE Electric plans to seek regulatory approval for capital expenditures consistent with prior ratemaking treatment. For further discussion of regulatory matters, see Note 9 to the Consolidated Financial Statements, "Regulatory Matters."
DTE Gas' capital investments over the 2019-2023 period are estimated at $2.5 billion comprised of $1.2 billion for base infrastructure, and $1.3 billion for gas main renewal, meter move out, and pipeline integrity programs. DTE Gas plans to seek regulatory approval for capital expenditures consistent with ratemaking treatment.
DTE Energy's non-utility businesses' capital investments are primarily for expansion, growth, and ongoing maintenance. Gas Storage and Pipelines' capital investments over the 2019-2023 period are estimated at $4.0 billion to $5.0 billion for gathering and pipeline investments and expansions. Power and Industrial Projects' capital investments over the 2019-2023 period are estimated at $1.0 billion to $1.4 billion for industrial energy services and RNG projects.


ENVIRONMENTAL MATTERS
The Registrants are subject to extensive environmental regulation. Additional costs may result as the effects of various substances on the environment are studied and governmental regulations are developed and implemented. Actual costs to comply could vary substantially. The Registrants expect to continue recovering environmental costs related to utility operations through rates charged to customers, as authorized by the MPSC.
Air — DTE Electric is subject to the EPA ozone and fine particulate transport and acid rain regulations that limit power plant emissions of SO2 and NOX. The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to controls on fossil-fueled power plants to reduce SO2, NOX, mercury, and other emissions. Additional rulemakings may occur over the next few years which could require additional controls for SO2, NOX, and other hazardous air pollutants. To comply with existing requirements, DTE Electric spent approximately $2.4 billion through 2018. DTE Electric does not anticipate additional capital expenditures through 2025.
The EPA has implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, in 2015 the EPA finalized performance standards for emissions of carbon dioxide from new and existing EGUs. In February 2016, the U.S. Supreme Court granted petitioners' requests for a stay of the carbon rules for existing EGUs (also known as the EPA Clean Power Plan) pending final review by the courts. The Clean Power Plan has no legal effect while the stay is in place. On March 28, 2017, a presidential executive order was issued on "Promoting Energy Independence and Economic Growth." The order instructs the EPA to review, and if appropriate, suspend, revise or rescind the Clean Power Plan rule. Following the issuance of this order, the federal government requested the U.S. Court of Appeals for the D.C. Circuit to hold all legal challenges in abeyance until the review of these regulations is completed. On October 10, 2017, the EPA proposed to rescind the Clean Power Plan and announced its intent to issue an ANPR seeking input as to whether it should replace the rule and, if so, what form it should take. In August 2018, the EPA proposed revised emission guidelines for GHGs from existing electric utility generating units. The proposed rule, named the Affordable Clean Energy (ACE) rule, is intended to replace the Clean Power Plan rule. Comments on the proposed ACE rule were due on October 31, 2018. It is not possible to determine the potential impact of the EPA's proposed ACE rule on existing sources at this time.
Pending or future legislation or other regulatory actions could have a material impact on DTE Electric's operations and financial position and the rates charged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. DTE Electric would seek to recover these incremental costs through increased rates charged to its utility customers, as authorized by the MPSC.
Increased costs for energy produced from traditional coal-based sources due to recent, pending, and future regulatory initiatives, could also increase the economic viability of energy produced from renewable, natural gas fueled generation, and/or nuclear sources, energy waste reduction initiatives, and the potential development of market-based trading of carbon instruments which could provide new business opportunities for DTE Energy's utility and non-utility segments. At the present time, it is not possible to quantify the financial impacts of these climate related regulatory initiatives on the Registrants or their customers.
See Items 1. and 2. Business and Properties and Note 18 to the Consolidated Financial Statements in Item 8 of this Report, "Commitments and Contingencies," for further discussion of Environmental Matters.


OUTLOOK
The next few years will be a period of rapid change for DTE Energy and for the energy industry. DTE Energy's strong utility base, combined with its integrated non-utility operations, position it well for long-term growth.
Looking forward, DTE Energy will focus on several areas that are expected to improve future performance:
electric and gas customer satisfaction;
electric distribution system reliability;
new electric generation;
gas distribution system renewal;
rate competitiveness and affordability;
regulatory stability and investment recovery for the electric and gas utilities;
employee safety and engagement;
cost structure optimization across all business segments;
cash, capital, and liquidity to maintain or improve financial strength; and
investments that integrate assets and leverage skills and expertise.
DTE Energy will continue to pursue opportunities to grow its businesses in a disciplined manner if it can secure opportunities that meet its strategic, financial, and risk criteria.

RESULTS OF OPERATIONS
Management’s Discussion and Analysis of Financial Condition and Results of Operations includes financial information prepared in accordance with GAAP, as well as the non-GAAP financial measures, Utility Margin and Non-utility Margin, discussed below, which DTE Energy uses as measures of its operational performance. Generally, a non-GAAP financial measure is a numerical measure of financial performance, financial position or cash flows that excludes (or includes) amounts that are included in (or excluded from) the most directly comparable measure calculated and presented in accordance with GAAP.
DTE Energy uses Utility Margin and Non-utility Margin, non-GAAP financial measures, to assess its performance by reportable segment.
Utility Margin includes electric and gas Operating Revenues net of Fuel, purchased power, and gas expenses. The utilities’ fuel, purchased power, and natural gas supply are passed through to customers, and therefore, result in changes to the utilities’ revenues that are comparable to changes in such expenses. As such, DTE Energy believes Utility Margin provides a meaningful basis for evaluating the utilities’ operations across periods, as it excludes the revenue effect of fluctuations in these expenses.
The Non-utility Margin relates to the Power and Industrial Projects and Energy Trading segments. For the Power and Industrial Projects segment, Non-utility Margin primarily includes Operating Revenues net of Fuel, purchased power, and gas expenses. Operating Revenues include sales of refined coal to third parties and the affiliated Electric utility, metallurgical coke and related by-products, petroleum coke, renewable natural gas, and electricity, as well as rental income and revenues from utility-type consulting, management, and operational services. For the Energy Trading segment, Non-utility Margin includes revenue and realized and unrealized gains and losses from physical and financial power and gas marketing, optimization, and trading activities, net of Purchased power and gas related to these activities. DTE Energy evaluates its operating performance of these non-utility businesses using the measure of Operating Revenues net of Fuel, purchased power, and gas expenses.


Utility Margin and Non-utility Margin are not measures calculated in accordance with GAAP and should be viewed as a supplement to and not a substitute for the results of operations presented in accordance with GAAP. Utility Margin and Non-utility Margin do not intend to represent operating income, the most comparable GAAP measure, as an indicator of operating performance and are not necessarily comparable to similarly titled measures reported by other companies.
The following sections provide a detailed discussion of the operating performance and future outlook of DTE Energy's segments. Segment information, described below, includes intercompany revenues and expenses, and other income and deductions that are eliminated in the Consolidated Financial Statements.
 2018 2017 2016
 (In millions)
Net Income (Loss) Attributable to DTE Energy by Segment     
Electric$664
 $606
 $622
Gas150
 146
 138
Gas Storage and Pipelines235
 275
 119
Power and Industrial Projects161
 138
 95
Energy Trading39
 72
 (45)
Corporate and Other(129) (103) (61)
Net Income Attributable to DTE Energy Company$1,120
 $1,134
 $868
ELECTRIC
The Results of Operations discussion for DTE Electric is presented in a reduced disclosure format in accordance with General Instruction I (2) (a) of Form 10-K for wholly-owned subsidiaries.
The Electric segment consists principally of DTE Electric. Electric results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Utility operations$5,298
 $5,102
 $5,225
Fuel and purchased power — utility1,552
 1,454
 1,532
Utility Margin3,746
 3,648
 3,693
Operation and maintenance1,437
 1,382
 1,408
Depreciation and amortization836
 753
 750
Taxes other than income307
 302
 284
Asset (gains) losses and impairments, net(1) 
 
Operating Income1,167
 1,211
 1,251
Other (Income) and Deductions310
 284
 276
Income Tax Expense193
 321
 353
Net Income Attributable to DTE Energy Company$664
 $606
 $622
See DTE Electric's Consolidated Statements of Operations in Item 8 of this Report for a complete view of its results. For an explanation of differences between the Electric segment and DTE Electric's Consolidated Statements of Operations, refer to Note 20 to the Consolidated Financial Statements, "Retirement Benefits and Trusteed Assets."
Utility Margin increased $98 million in 2018 and decreased $45 million in 2017. Revenues associated with certain mechanisms and surcharges are offset by related expenses elsewhere in the Registrants' Consolidated Statements of Operations.


The following table details changes in various Utility Margin components relative to the comparable prior period:
 2018 2017
 (In millions)
Weather$152
 $(109)
Implementation of new rates51
 124
Regulatory mechanism — TRM40
 (26)
PSCR disallowance in 201713
 (13)
Base sales(3) (26)
TCJA rate reduction(156) 
Other regulatory mechanisms and other1
 5
Increase (decrease) in Utility Margin$98
 $(45)
 2018 2017 2016
 (In thousands of MWh)
DTE Electric Sales     
Residential15,959
 14,885
 15,875
Commercial17,282
 17,283
 17,521
Industrial10,324
 9,897
 10,004
Other221
 258
 264
 43,786
 42,323
 43,664
Interconnection sales(a)
2,796
 2,623
 2,334
Total DTE Electric Sales46,582
 44,946
 45,998
      
DTE Electric Deliveries     
Retail and wholesale43,786
 42,323
 43,664
Electric retail access, including self-generators(b)
4,737
 4,820
 4,936
Total DTE Electric Sales and Deliveries48,523
 47,143
 48,600

(a)Represents power that is not distributed by DTE Electric.
(b)Represents deliveries for self-generators that have purchased power from alternative energy suppliers to supplement their power requirements.
DTE Electric sales increased for residential, commercial, and industrial primarily due to favorable weather in 2018.
Operation and maintenance expense increased $55 million in 2018 and decreased $26 million in 2017. The increase in 2018 was primarily due to increased uncollectible expense of $34 million due to customer billing initiatives following implementation of the new billing system, increased power plant generation expense of $24 million, an increase in energy waste reduction expense of $10 million to meet higher energy savings targets, partially offset by decreased distribution operations expense of $13 million. The decrease in 2017 was primarily due to decreased power plant generation expenses of $66 million, partially offset by increased storm restoration expenses of $27 million, and increased line clearance expenses of $10 million. The decrease in power plant generation includes an increase of $6 million of costs related to the 2016 fire at a generation facility, offset by $21 million of insurance proceeds received in 2017.
Depreciation and amortization expense increased $83 million in 2018 and increased $3 million in 2017. In 2018, the increase was primarily due to an increase to depreciable base of $46 million and an increase of $42 million associated with the TRM, partially offset by a decrease in regulatory asset amortization of $5 million. In 2017, the increase was due to $45 million of increased expense from an increased depreciable base, partially offset by a decrease of $29 million associated with the TRM, and a decrease of $13 million in amortization of regulatory assets.


Other (Income) and Deductions increased $26 million in 2018 and increased $8 million in 2017. The increase in 2018 was primarily due to higher interest expense of $9 million and change in investment earnings (loss of $11 million in 2018 compared to a gain of $26 million in 2017), partially offset by decreased non-operating retirement benefits expense of $13 million and a contribution to the DTE Energy Foundation of $7 million in 2017. The increase in 2017 was primarily due to higher interest expense of $10 million, lower interest income of $8 million related to a sales and use tax settlement received in 2016, and a $7 million contribution to the DTE Energy Foundation, partially offset by $12 million of higher investment earnings and a $3 million decrease in Low Income Self-Sufficiency Plan (LSP) contributions to not-for-profit organizations in 2016.
Outlook DTE Electric will continue to move forward in its efforts to achieve operational excellence, sustain strong cash flows, and earn its authorized return on equity. DTE Electric expects that planned significant capital investments will result in earnings growth. DTE Electric will maintain a strong focus on customers by increasing reliability and satisfaction while keeping customer rate increases affordable. Looking forward, additional factors may impact earnings such as weather, the outcome of regulatory proceedings, benefit plan design changes, investment returns and changes in discount rate assumptions in benefit plans and health care costs, uncertainty of legislative or regulatory actions regarding climate change, and effects of energy waste reduction programs.
DTE Electric filed a rate case with the MPSC on July 6, 2018 requesting an increase in base rates of $328 million based on a projected twelve-month period ending April 30, 2020. The requested increase in base rates is primarily due to an increase in net plant resulting from infrastructure investments, depreciation expense, as requested in the 2016 DTE Electric Depreciation Case Filing, and reliability improvement projects. The rate filing also requests an increase in return on equity from 10.0% to 10.5% and includes projected changes in sales, operation and maintenance expenses, and working capital. In addition, the rate filing requests an Infrastructure Recovery Mechanism to recover the incremental revenue requirement associated with certain distribution, fossil generation, and nuclear generation capital expenditures through 2022. DTE Electric also included Calculation C in this filing to address all remaining issues relative to the enactment of the TCJA, which is primarily the remeasurement of deferred taxes and how the amounts deferred as Regulatory liabilities will flow to ratepayers. A final MPSC order in this case is expected by May 2019. Refer to Note 9 to the Consolidated Financial Statements, “Regulatory Matters” for additional information.
GAS
The Gas segment consists principally of DTE Gas. Gas results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Utility operations$1,436
 $1,388
 $1,324
Cost of gas — utility446
 443
 454
Utility Margin990
 945
 870
Operation and maintenance502
 449
 440
Depreciation and amortization133
 123
 106
Taxes other than income73
 65
 64
Asset (gains) losses and impairments, net
 
 4
Operating Income282
 308
 256
Other (Income) and Deductions65
 84
 41
Income Tax Expense67
 78
 77
Net Income Attributable to DTE Energy Company$150
 $146
 $138
Utility Margin increased $45 million in 2018 and increased $75 million in 2017. Revenues associated with certain surcharges are offset by related expenses elsewhere in DTE Energy's Consolidated Statements of Operations.


The following table details changes in various Utility Margin components relative to the comparable prior period:
 2018 2017
 (In millions)
Weather$46
 $(6)
Implementation of new rates15
 80
Midstream storage and transportation revenues15
 (5)
Regulatory mechanism — RDM(3) 4
TCJA rate reduction(40) 
Other regulatory mechanisms and other12
 2
Increase in Utility Margin$45
 $75
 2018 2017 2016
 (In Bcf)
Gas Markets     
Gas sales135
 119
 116
End-user transportation187
 165
 182
 322
 284
 298
Intermediate transportation329
 260
 214
Total Gas sales651
 544
 512
Operation and maintenance expense increased $53 million in 2018 and increased $9 million in 2017. The increase in 2018 was primarily due to increased uncollectible expense of $28 million due to customer billing initiatives following implementation of a new customer billing system and higher gas operations expenses of $22 million, which included increased investment spending and higher pipeline integrity expenses. The increase in 2017 was primarily due to increased corporate expenses of $3 million and increased gas operations expenses of $3 million.
Depreciation and amortization expense increased $10 million in 2018 and increased $17 million in 2017. The increase in 2018 was primarily due to an increased depreciable base. The increase in 2017 was primarily due to an increased depreciable base and higher depreciation rates.
Other (Income) and Deductions decreased $19 million in 2018 and increased $43 million in 2017. The decrease in 2018 was primarily due to lower contributions to the DTE Energy Foundation and other not-for-profit organizations of $27 million, partially offset by higher net interest expense of $6 million. The increase in 2017 was primarily due to increased non-operating retirement benefits expenses of $31 million, increased contributions to the DTE Energy Foundation and other not-for-profit organizations of $7 million and higher interest expense of $5 million.
Outlook — DTE Gas will continue to move forward in its efforts to achieve operational excellence, sustain strong cash flows, and earn its authorized return on equity. DTE Gas expects that planned significant infrastructure capital investments will result in earnings growth. Looking forward, additional factors may impact earnings such as weather, the outcome of regulatory proceedings, benefit plan design changes, and investment returns and changes in discount rate assumptions in benefit plans and health care costs. DTE Gas expects to continue its efforts to improve productivity and decrease costs while improving customer satisfaction with consideration of customer rate affordability.
DTE filed its Calculation C case with the MPSC on November 16, 2018 to reduce the revenue requirement by $12 million related to the amortization of deferred tax remeasurement. Calculation C addresses all remaining issues relative to the enactment of the TCJA, which is primarily the remeasurement of deferred taxes and how the amounts deferred as Regulatory liabilities will flow to ratepayers. Refer to Note 9 to the Consolidated Financial Statements, “Regulatory Matters” for additional information.


GAS STORAGE AND PIPELINES
The Gas Storage and Pipelines segment consists of the non-utility gas pipelines and storage businesses. Gas Storage and Pipelines results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Non-utility operations$485
 $453
 $302
Cost of gas — Non-utility22
 30
 6
Operation and maintenance103
 83
 81
Depreciation and amortization82
 76
 45
Taxes other than income8
 8
 4
Asset (gains) losses and impairments, net
 2
 
Operating Income270
 254
 166
Other (Income) and Deductions(61) (18) (31)
Income Tax Expense (Benefit)68
 (30) 71
Net Income263
 302
 126
Less: Net Income Attributable to Noncontrolling Interests28
 27
 7
Net Income Attributable to DTE Energy Company$235
 $275
 $119
Operating Revenues — Non-utility operations increased $32 million in 2018 and increased $151 million in 2017. The increase in both periods was primarily due to increased pipeline and gathering volumes. The 2017 increase was also due to the acquisition of AGS and SGG in October 2016.
Cost of gas — Non-utility decreased $8 million in 2018 and increased $24 million in 2017. The 2018 decrease was driven by lower physical purchases of gas from AGS customers for resale to optimize available transportation capacity. The 2017 increase was driven by higher physical purchases of gas from AGS customers for resale to optimize available transportation capacity.
Operation and maintenance expense increased $20 million in 2018 and increased $2 million in 2017. The 2018 increase was primarily due to increased labor related expenses and additional compression activity on the Bluestone Pipeline and Susquehanna gathering systems.
Depreciation and amortization expense increased $6 million in 2018 and increased $31 million in 2017. The 2017 increase was primarily due to the acquisition of AGS and SGG in October 2016.
Other (Income) and Deductions increased $43 million in 2018 and decreased $13 million in 2017. The 2018 increase was primarily due to increased earnings from pipeline investments and a $16 million net loss on extinguishment of debt within the storage business in 2017, partially offset by higher interest expense. The 2017 decrease was primarily due to a $16 million net loss on extinguishment of debt within the storage business and contributions to the DTE Energy Foundation and other not-for-profit organizations, partially offset by increased earnings from pipeline investments.
Income Tax Expense (Benefit) increased $98 million in 2018 and decreased $101 million in 2017. The changes were primarily driven by the $115 million remeasurement of deferred tax assets and liabilities to reflect the reduction in the corporate tax rate from the enactment of the TCJA in December 2017. The 2017 change was partially offset by increased tax expense on higher earnings in 2017.
Net Income Attributable to Noncontrolling Interests increased $1 million in 2018 and increased $20 million in 2017. The 2017 increase was primarily due to the acquisition of SGG in October 2016.
Outlook — DTE Energy believes its long-term agreements with producers and the quality of the natural gas reserves in the Marcellus/Utica region soundly position the gathering systems for future revenues.
NEXUS Pipeline was placed in service in in October 2018. The NEXUS Pipeline provides a transportation path for Appalachian Basin shale gas, including Utica and Marcellus shale gas, directly to consuming markets in northern Ohio, southeastern Michigan, and Dawn Ontario. DTE Energy owns a 50% partnership interest in the NEXUS Pipeline with an investment balance of $1.26 billion at December 31, 2018.


On January 11, 2019, NEXUS signed an agreement to purchase Generation Pipeline, LLC, a public utility regulated by the Public Utilities Commission of Ohio. This 23-mile pipeline system supplies gas to industrial customers in the Toledo, OH area, has existing interconnects with ANR Pipeline Company and Panhandle Eastern Pipeline Company, and is located 4 miles away from Nexus. The transaction is expected to close in the first half of 2019 upon regulatory approvals.
AGS and SGG provide a platform for midstream growth and access to further investment opportunities in the Appalachian basin, an additional connection to the NEXUS Pipeline which should drive incremental volumes on the NEXUS Pipeline, and producer relationships that may lead to more partnering opportunities.
Gas Storage and Pipelines expects to maintain its steady growth by developing an asset portfolio with multiple growth platforms through investment in new projects and expansions. Gas Storage and Pipelines will continue to look for additional investment opportunities and other storage and pipeline projects at favorable prices.
POWER AND INDUSTRIAL PROJECTS
The Power and Industrial Projects segment is comprised primarily of projects that deliver energy and utility-type products and services to industrial, commercial, and institutional customers, produce reduced emissions fuel, and sell electricity and pipeline-quality gas from renewable energy projects. Power and Industrial Projects results are discussed below:
 2018 2017 2016
 (In millions)
Operating Revenues — Non-utility operations$2,204
 $2,089
 $1,906
Fuel, purchased power, and gas — non-utility1,888
 1,813
 1,640
Non-utility Margin316
 276
 266
Operation and maintenance363
 342
 317
Depreciation and amortization67
 72
 72
Taxes other than income12
 11
 13
Asset (gains) losses and impairments, net27
 20
 (1)
Operating Loss(153) (169) (135)
Other (Income) and Deductions(89) (63) (49)
Income Taxes     
Benefit(7) (42) (26)
Production Tax Credits(188) (153) (114)
 (195) (195) (140)
Net Income131
 89
 54
Less: Net Loss Attributable to Noncontrolling Interests(30) (49) (41)
Net Income Attributable to DTE Energy Company$161
 $138
 $95


Operating Revenues — Non-utility operations increased $115 million in 2018 and increased $183 million in 2017. The changes are due to the following:
 2018
 (In millions)
Higher demand due to improved conditions in the steel business$59
Higher production in the renewables business25
Higher production, offset by lower coal prices in the REF business18
Higher sales primarily associated with new contracts in the on-site business13
 $115
  
 2017
 (In millions)
Higher demand due to improved conditions in the steel business$107
Higher production driven by new projects, offset by lower coal prices in the REF business102
Lower production and one-time recovery in 2016, offset by an acquisition in the renewables business(9)
Lower sales primarily associated with expired contracts in the on-site business(17)
 $183
Non-utility Margin increased $40 million in 2018 and increased $10 million in 2017. The changes are due to the following:
 2018
 (In millions)
Higher production in the renewables business$20
Higher sales primarily associated with new contracts in the on-site business12
Higher demand due to improved conditions in the steel business8
 $40
  
 2017
 (In millions)
Higher demand due to improved conditions in the steel business$42
Lower production and one-time recovery in 2016 in the renewables business(11)
Lower sales primarily associated with expired contracts in the on-site business(15)
Other(6)
 $10
Operation and maintenance expense increased $21 million in 2018 and increased $25 million in 2017. The 2018 increase was primarily due to higher production in the REF business of $11 million and new contracts in the on-site business of $8 million. The 2017 increase was primarily due to an increase in maintenance spending driven by improved conditions in the steel business of $16 million, higher maintenance and a new acquisition in the renewables business of $7 million, and an increase associated with new projects in the REF business of $5 million, offset by lower spending as a result of Shenango plant closure activities in the first half of 2016 of $6 million.
Asset (gains) losses and impairments, net increased $7 million in 2018 from the net loss of $20 million in 2017 and decreased $21 million in 2017 from the net gain of $1 million in 2016. The 2018 increase was primarily due to $15 million of a liability adjustment related to contingent consideration and an $8 million asset write-off associated with the renewable business in anticipation of a contract ending in 2020. The 2017 decrease was primarily due to an impairment in the REF business of $14 million and an impairment of a petroleum coke project of $6 million.


Other (Income) and Deductions increased $26 million in 2018 and increased $14 million in 2017. The 2018 increase was primarily due to higher production in the REF business of $20 million and decreased contributions to the DTE Energy Foundation of $4 million. The 2017 increase was primarily due to increased equity earnings in the renewable business of $9 million and insurance settlements in the renewable and REF businesses of $6 million, offset by increased contributions to the DTE Energy Foundation of $6 million.
Income Taxes — Benefit decreased by $35 million in 2018 and increased by $16 million in 2017. The 2018 decrease was primarily due to the 2017 remeasurement of deferred tax assets and liabilities to reflect the reduction in the corporate tax rate from the enactment of the TCJA in December 2017. The increase in 2017 was primarily due to the remeasurement of deferred tax assets and liabilities to reflect the reduction in the corporate tax rate from the enactment of the TCJA in December 2017 of $21 million, an increase due to higher pretax loss of $7 million, and a decrease due to a worthless stock deduction associated with the Shenango closure in 2016 of $10 million.
Income Taxes — Production Tax Credits increased by $35 million in 2018 and increased $39 million in 2017. The increase in both periods was primarily due to higher production in the REF business.
Net Loss Attributable to Noncontrolling Interests decreased by $19 million in 2018 and increased by $8 million in 2017. The 2018 decrease was primarily due to termination of a project in the REF business. The 2017 increase was primarily due to a change in the ownership percentage in one of the REF projects of $8 million.
Outlook — Power and Industrial Projects has constructed and placed in service REF facilities at ten sites including facilities located at seven third-party owned coal-fired power plants. DTE Energy has sold membership interests in five of the facilities and entered into lease arrangements in three of the facilities. Three REF facilities will phase out in 2019 with the remaining seven to be phased out at the end of 2021.
Power and Industrial Projects will continue to leverage its extensive energy-related operating experience and project management capability to develop additional energy projects to serve energy intensive industrial customers.
ENERGY TRADING
Energy Trading focuses on physical and financial power and natural gas marketing and trading, structured transactions, enhancement of returns from its asset portfolio, and optimization of contracted natural gas pipeline transportation and storage positions. Energy Trading also provides natural gas, power, and related services, which may include the management of associated storage and transportation contracts on the customers' behalf, and the supply or purchase of renewable energy credits to various customers. Energy Trading results are discussed below:
2015 2014 20132018 2017 2016
(In millions)(In millions)
Operating Revenues — Non-utility operations$2,459
 $3,762
 $1,771
$5,557
 $4,277
 $2,575
Purchased power and gas — non-utility2,417
 3,478
 1,782
5,417
 4,077
 2,552
Gross Margin42
 284
 (11)
Non-utility Margin140
 200
 23
Operation and maintenance67
 70
 72
75
 68
 63
Depreciation and amortization2
 1
 1
5
 5
 3
Taxes other than income4
 4
 4
5
 4
 2
Operating Income (Loss)(31) 209
 (88)55
 123
 (45)
Other (Income) and Deductions6
 10
 8
3
 2
 29
Income Tax Expense (Benefit)(15) 77
 (38)13
 49
 (29)
Net Income (Loss) Attributable to DTE Energy Company$(22) $122
 $(58)$39
 $72
 $(45)
Operating Revenues — Non-utility operations and Purchased power and gas — non-utility were impacted by a decrease in gas prices, partially offsetprimarily by an increase in volumes primarily in the gas structured strategy for the year ended December 31, 2015. For 2014, these line items were impacted byas well as an increase in gas volumesprices for the years ended December 31, 2018 and prices,December 31, 2017, primarily in the gas structured strategy.


GrossNon-utility Margin decreased $242$60 million in 20152018 and increased $295$177 million in 2014.2017. The decreasechange in 2015 and the increase in 2014 areboth periods was primarily due to timing from MTM adjustments on certain transactionsthe unrealized and realized margins presented in the gas structured strategy.following tables:
The decrease
 2018
 (In millions)
Unrealized Margins(a)
 
Favorable results, primarily in the power trading strategy$20
Unfavorable results, primarily in gas structured, and power full requirements strategies(b)
(100)
 (80)
Realized Margins(a)
 
Favorable results, primarily in the gas structured strategy54
Unfavorable results, primarily in the power full requirements strategy(c)
(34)
 20
Decrease in Non-utility Margin$(60)

(a)Natural gas structured transactions typically involve a physical purchase or sale of natural gas in the future and/or natural gas basis financial instruments which are derivatives and a related non-derivative pipeline transportation contract. These gas structured transactions can result in significant earnings volatility as the derivative components are marked-to-market without revaluing the related non-derivative contracts.
(b)Amount includes $74 million of timing related losses related to gas strategies which will reverse in future periods as the underlying contracts settle.
(c)Amount includes $11 million of timing related gains related to gas strategies recognized in previous periods that reversed as the underlying contracts settled.
 2017
 (In millions)
Unrealized Margins(a)
 
Favorable results, primarily in gas structured and gas full requirements strategies(b)
$113
Unfavorable results, primarily in power and gas trading and power full requirements strategies(26)
 87
Realized Margins(a)
 
Favorable results, primarily in gas structured, environmental trading and gas storage strategies(c)
103
Unfavorable results, primarily in the power full requirements strategy(13)
 90
Increase in Non-utility Margin$177

(a)Natural gas structured transactions typically involve a physical purchase or sale of natural gas in the future and/or natural gas basis financial instruments which are derivatives and a related non-derivative pipeline transportation contract. These gas structured transactions can result in significant earnings volatility as the derivative components are marked-to-market without revaluing the related non-derivative contracts.
(b)Amount includes $113 million of timing related gains related to gas strategies which will reverse in future periods as the underlying contracts settle.
(c)Amount includes $95 million of timing related losses related to gas strategies recognized in previous periods that reversed as the underlying contracts settled.
Other (Income) and Deductions increased$1 million in Gross Margin2018 and decreased $27 million in 2015 represents a $155 million decrease in realized margins and an $87 million decrease in unrealized margins. The $155 million decrease in realized margins is2017 due to $201 million of unfavorable results, primarilycontributions to the DTE Energy Foundation in gas structured, and power trading strategies, offset by $46 million of favorable results, primarily in power full requirements and gas transportation strategies. The $87 million decrease in unrealized margins is due to $120 million of unfavorable results, primarily in the gas structured strategy, offset by $33 million of favorable results, primarily in power full requirements and gas transportation strategies.
The increase in Gross Margin in 2014 represents a $92 million increase in realized margins and a $203 million increase in unrealized margins. The $92 million increase in realized margins is due to $149 million of favorable results, primarily in gas structured and gas transportation strategies, offset by $57 million of unfavorable results, primarily in power full requirements, gas full requirements, and gas trading strategies. The $203 million increase in unrealized margins is due to $211 million of favorable results, primarily in gas structured and gas full requirements strategies, offset by $8 million of unfavorable results, primarily in the power full requirements strategy.
During the first quarter of 2015, Energy Trading experienced slightly colder than normal weather conditions, on average, in the gas and power markets served, unlike the extreme weather conditions in the midwest and northeast that Energy Trading experienced in the first quarter of 2014. Consequently, this led to less favorable results in gas asset optimization strategies due to lower gas prices as compared to 2014, partially offset by lower realized losses from Energy Trading's power full requirements strategy as compared to 2014.

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Natural gas structured transactions typically involve a physical purchase or sale of natural gas in the future and/or natural gas basis financial instruments which are derivatives and a related non-derivative pipeline transportation contract. These gas structured transactions can result in significant earnings volatility as the derivative components are marked-to-market without revaluing the related non-derivative contracts. Included in the $201 million of unfavorable realized results for the year ended December 31, 2015 related to gas strategies is $113 million of timing related gains and losses recognized in previous years that reversed as the underlying contracts settled. The $113 million of timing related items is comprised of a reversal of timing related losses of $65 million in 2014 and a reversal of timing gains of $48 million in 2015. Included in the $120 million of unfavorable unrealized results for the year ended December 31, 2015, related to gas strategies is $126 million of timing related gains and losses. The $126 million of timing related items is the variance of timing gains of $102 million in 2014 and timing losses of $24 million in 2015, which will reverse in future periods as the underlying contracts settle.
Included in the $149 million of favorable realized results for the year ended December 31, 2014 in Energy Trading's gas strategies, is $65 million of timing related losses recognized in 2013 that reversed as the underlying contracts were settled. Included in the $211 million of favorable unrealized results for the year ended December 31, 2014 in Energy Trading's gas strategies, is $102 million of timing related gains which will reverse in future periods, and the absence of $89 million of timing related losses in 2013.2016.
Outlook — In the near-term, Energy Trading expects market conditions to remain challenging, and the profitability of this segment may be impacted by the volatility in commodity prices and the uncertainty of impacts associated with financial reform, regulatory changes, and changes in operating rules of regional transmission organizations.RTOs. Significant portions of the Energy Trading portfolio are economically hedged. Most financial instruments and physical power and natural gas contracts are deemed derivatives, whereas natural gas inventory, pipeline transportation, renewable energy credits, and storage assets are not derivatives. As a result, DTE Energy Trading will experience earnings volatility as derivatives are marked-to-market without revaluing the underlying non-derivative contracts and assets. Energy Trading's strategy is to economically manage the price risk of these underlying non-derivative contracts and assets with futures, forwards, swaps, and options. This results in gains and losses that are recognized in different interim and annual accounting periods.
See also the "Fair Value" in the "Capital Resources and Liquidity" section that followsherein and Notes 1112 and 1213 to the Consolidated Financial Statements in Item 8 of this Report, “Fair Value”"Fair Value" and "Financial and Other Derivative Instruments",Instruments," respectively.


CORPORATE AND OTHER
Corporate and Other includes various holding company activities, and holds certain non-utility debt, and holds energy-related investments. The 20152018 net loss of $48 million represents an improvement of $9 million from the 2014 net loss of $57 million due primarily to 2014 investment impairments and lower deferred tax expense related to the impact of New York state income tax reform enacted in March 2014, partially offset by higher interest expense. The 2014 net loss of $57$129 million represents an increase of $13$26 million from the 20132017 net loss of $44$103 million primarily due primarily to increased impairments of investmentsa reduction in the corporate tax rate from the TCJA in December 2017, higher interest expense and increased contributions to other not-for-profit organizations, partially offset by the remeasurement of deferred tax expense relatedassets and liabilities to New York statereflect the reduction in the corporate tax rate from the enactment of the TCJA in 2017. The 2017 net loss of $103 million represents an increase of $42 million from the 2016 net loss of $61 million primarily due to the remeasurement of deferred tax assets and liabilities to reflect the reduction in the corporate tax rate from the enactment of the TCJA in December 2017 resulting in income tax reform enacted in March 2014.expense of $34 million, and the contribution of land and improvements to the DTE Energy Beacon Park Foundation.
See Note 910 to the Consolidated Financial Statements in Item 8 of this Report, "Income Taxes".Taxes."

CAPITAL RESOURCES AND LIQUIDITY
Cash Requirements
DTE Energy uses cash to maintain and invest in the electric and natural gas utilities, to grow the non-utility businesses, to retire and pay interest on long-term debt, and to pay dividends. DTE Energy believes it will have sufficient internal and external capital resources to fund anticipated capital and operating requirements. DTE Energy expects that cash from operations in 20162019 will be approximately $1.8 billion, or approximately $100 million lower than 2015, due primarily to higher working capital requirements.$2.4 billion. DTE Energy anticipates base level utility capital investments;investments, including environmental, renewable, and energy optimizationwaste reduction expenditures; expenditures for non-utility businesses; and contributions to equity method investees in 20162019 of approximately $2.7$3.9 billion. DTE Energy plans to seek regulatory approval to include utility capital expenditures in regulatory rate base consistent with prior treatment. Capital spending for growth of existing or new non-utility businesses will depend on the existence of opportunities that meet strict risk-return and value creation criteria.

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2015 2014 20132018 2017 2016
Cash and Cash Equivalents(In millions)(In millions)
Cash Flows From (Used For)     
Operating Activities:     
Cash Flow From (Used For)     
Operating Activities     
Net Income$720
 $911
 $668
$1,118
 $1,112
 $834
Adjustments to reconcile Net Income to Net cash from operating activities:          
Depreciation and amortization852
 1,145
 1,094
1,124
 1,030
 976
Nuclear fuel amortization46
 48
 38
45
 53
 58
Allowance for equity funds used during construction(21) (21) (15)(28) (23) (21)
Deferred income taxes237
 356
 164
114
 196
 265
Asset (gains) losses and impairments, net107
 (4) (8)29
 38
 8
Working capital and other(30) (596) 213
278
 (289) (36)
Net cash from operating activities1,911
 1,839
 2,154
2,680
 2,117
 2,084
Investing Activities:     
Investing Activities     
Plant and equipment expenditures — utility(1,817) (1,784) (1,534)(2,439) (2,037) (1,898)
Plant and equipment expenditures — non-utility(203) (265) (342)(274) (213) (147)
Acquisition(241) 
 
Proceeds from sale of assets16
 45
 36
Restricted cash for debt redemption, principally Securitization, net97
 3
 (1)
Acquisition, net of cash acquired
 
 (1,147)
Contributions to equity method investees(637) (299) (239)
Other(56) (59) (65)3
 (13) 41
Net cash used for investing activities(2,204) (2,060) (1,906)(3,347) (2,562) (3,390)
Financing Activities:     
Financing Activities     
Issuance of long-term debt, net of issuance costs956
 1,736
 1,234
1,432
 1,398
 2,035
Redemption of long-term debt(286) (1,237) (961)(105) (385) (807)
Repurchase of long-term debt
 
 (59)
Issuance of equity units, net of issuance costs
 
 654
Short-term borrowings, net101
 267
 (109)(12) 122
 
Issuance of common stock9
 
 39
Repurchase of common stock
 (52) 

 (51) (33)
Dividends on common stock(501) (470) (445)
Dividends on common stock and other(620) (592) (531)
Contributions from noncontrolling interests, principally REF entities53
 50
 114
Distributions to noncontrolling interests(48) (40) (5)
Other3
 (27) (19)(46) (81) (9)
Net cash from (used for) financing activities282
 217
 (261)
Net Decrease in Cash and Cash Equivalents$(11) $(4) $(13)
Net cash from financing activities654
 421
 1,359
Net Increase (Decrease) in Cash, Cash Equivalents, and Restricted Cash$(13) $(24) $53
Cash from Operating Activities
A majority of DTE Energy's operating cash flows are provided by the electric and natural gas utilities, which are significantly influenced by factors such as weather, electric retail access, regulatory deferrals, regulatory outcomes, economic conditions, changes in working capital, and operating costs.
Cash from operations increased $72$563 million in 2015.2018. The increase in operating cash flows reflects a decrease in cash expenditures for working capital items, partially offset by lower Net Income after adjusting for non-cash and non-operating items. The decreases in depreciation and amortization and deferred income taxes are partially offset by the increase in asset (gains) losses and impairments, which is primarily due to DTE Energy's closure of the Shenango coke battery plant in 2015. See Note 4 to the Consolidated Financial Statements in Item 8 of this Report, "Acquisitions and Exit Activities".
Cash from operations decreased $315 million in 2014. The reduction in operating cash flows reflects an increase in cash expenditures for working capital items, partially offset by higher Net Income after adjustingadjustments for non-cash and non-operating items, (primarily depreciationprimarily Depreciation and amortization and deferredworking capital adjustments, partially offset by a decrease to Deferred income taxes).taxes.
Cash from operations increased $33 million in 2017. The increase in operating cash flows reflects an increase in Net Income and adjustments for non-cash and non-operating items, primarily Depreciation and amortization, and Asset (gains) losses and impairments, partially offset by a decrease to Deferred income taxes and working capital adjustments.
The change in working capital items in 20152018 primarily related to increases in regulatorycash from Accounts receivable, Accrued pension liability, Derivative assets and liabilities, derivativeand Other current and noncurrent assets and liabilities, accounts receivable, net, and inventories, partially offset by decreases in accrued pension liability, accruedincreases of cash used for Equity earnings of equity method investees, Prepaid postretirement benefit costs, Accrued postretirement liability, and accounts payable.Regulatory assets and liabilities. The change in working capital items in 20142017 primarily related to fuel inventories, derivativeincreases of cash used for Accounts Receivable, Inventories, Accrued pension liability, Derivative assets and liabilities, Equity earnings of equity method investees, and regulatoryOther current and noncurrent assets and liabilities, partially offset by increases in cash from the change in accounts receivable, net, accounts payable,Accrued postretirement liability, and pensionRegulatory assets and other postretirement liabilities.

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Cash used for Investing Activities
Cash inflows associated with investing activities are primarily generated from the sale of assets, while cash outflows are the result of plant and equipment expenditures and acquisitions.expenditures. In any given year, DTE Energy looks to realize cash from under-performing or non-strategic assets or matured, fully valued assets.
Capital spending within the utility businesses is primarily to maintain and improve the electric generation and the electric and natural gas distribution infrastructure, and to comply with environmental regulations and renewable energy requirements.
Capital spending within the non-utility businesses is primarily for ongoing maintenance, expansion, and growth. DTE Energy looks to make growth investments that meet strict criteria in terms of strategy, management skills, risks, and returns. All new investments are analyzed for their rates of return and cash payback on a risk adjusted basis. DTE Energy has been disciplined in how it deploys capital and will not make investments unless they meet the criteria. For new business lines, DTE Energy initially invests based on research and analysis. DTE Energy starts with a limited investment, evaluates the results, and either expands or exits the business based on those results. In any given year, the amount of growth capital will be determined by the underlying cash flows of DTE Energy, with a clear understanding of any potential impact on its credit ratings.
Net cash used for investing activities increased $144$785 million in 20152018 due primarily to DTE Energy's $241 million acquisition in January. This is partially offset by thean increase in restricted cash for debt redemption as this activity primarily relatesPlant and equipment expenditures and Contributions to Securitization bonds that were fully redeemed in March 2015.equity method investees, principally to NEXUS.
Net cash used for investing activities increased $154decreased $828 million in 20142017 due primarily to increased capital expenditures by the utility businesses,DTE Energy's 2016 acquisition of midstream natural gas assets, partially offset by decreased capitalincreased Plant and equipment expenditures, by the non-utility businessContributions to equity method investees, principally to NEXUS, and increased proceeds from saletwo acquisitions of assets.renewable gas recovery sites, which are presented in Investing Activities — Other.
Cash from (used for) Financing Activities
DTE Energy relies on both short-term borrowing and long-term financing as a source of funding for capital requirements not satisfied by its operations.
DTE Energy's strategy is to have a targeted debt portfolio blend of fixed and variable interest rates and maturity. DTE Energy continually evaluates its leverage target, which is currently 50% to 53%,targets balance sheet financial metrics to ensure it is consistent with the objective of a strong investment grade debt rating.
Net cash from financing activities increased $65$233 million in 2015.2018. The increase iswas primarily attributabledue to decreased redemptionsthe reduction of Redemption of long-term debt which is offset by decreasesand Repurchases of common stock and an increase in issuancesIssuance of long-term debt, short-termpartially offset by an increase in cash used for repayments of Short-term borrowings and repurchase ofan increase in Dividends on common stock.
Net cash from financing activities increased $478decreased $938 million in 2014.2017. The increase isdecrease was primarily attributabledue to increasesa decrease in short-term borrowings and issuancesIssuances of long-term debt and equity units, Contributions from noncontrolling interests, an increase in Dividends on common stock, and Distributions to noncontrolling interests, partially offset by increased redemptionsan increase to Short-term borrowings, and a decrease to Redemptions and Repurchases of long-term debt, repurchases of common stock, and increased dividends on common stock.debt.
Outlook
DTE Energy expects cash flows from operations to increase over the long-term, primarily as a result of growth from the utility and non-utility businesses. Growth in the utilities is expected to be driven primarily by capital spending to maintain and improve the electric generation and electric and natural gas distribution infrastructure and to comply with new and existing state and federal regulations that will result in additional environmental and renewable energy investments which will increase the base from which rates are determined. Non-utility growth is expected from additional investments, primarily in the Gas Storage and Pipelines and Power and Industrial Projects segments.
DTE Energy may be impacted by the timing of collection or refund of various recovery and tracking mechanisms, as a result of timing of MPSC orders. Energy prices are likely to be a source of volatility with regard to working capital requirements for the foreseeable future. DTE Energy continues its efforts to identify opportunities to improve cash flows through working capital initiatives and maintaining flexibility in the timing and extent of long-term capital projects.
DTE Energy has approximately $500 million$1.5 billion in long-term debt, including capital leases, maturing in the next twelve months. The repayment of the debt is expected to be paid through internally generated funds or the issuance of long-term debt.


DTE Energy has approximately $1.5$1.4 billion of available liquidity at December 31, 2015,2018, consisting of cash and amounts available under unsecured revolving credit agreements.

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DTE Energy expects to issue approximately $100equity up to $250 million of common stock in 20162019 through itsthe pension and other employee benefit plans.plans, which is exclusive from any amounts related to the Equity Units described in Note 14 to the Consolidated Financial Statements, "Long-Term Debt."
At the discretion of management, and depending upon financial market conditions, DTE Energy anticipates making 2016up to $150 million in contributions, including $100 million of DTE Electric contributions, to the qualified pension plans of up to $180 million and up to $20 millionin 2019. DTE Energy does not anticipate making any contributions to the other postretirement benefit plans. The planned contributions will be madeplans in cash or a combination of cash and DTE Energy common stock.2019.
Various subsidiaries and equity investees of DTE Energy have entered into contracts which contain ratings triggers and are guaranteed by DTE Energy. These contracts contain provisions which allow the counterparties to require that DTE Energy post cash or letters of credit as collateral in the event that DTE Energy's credit rating is downgraded below investment grade. Certain of these provisions (known as “hard triggers”"hard triggers") state specific circumstances under which DTE Energy can be required to post collateral upon the occurrence of a credit downgrade, while other provisions (known as “soft triggers”"soft triggers") are not as specific. For contracts with soft triggers, it is difficult to estimate the amount of collateral which may be requested by counterparties and/or which DTE Energy may ultimately be required to post. The amount of such collateral which could be requested fluctuates based on commodity prices (primarily natural gas, power, and coal) and the provisions and maturities of the underlying transactions. As of December 31, 2015,2018, DTE Energy's contractual obligation to post collateral in the form of cash or letterletters of credit in the event of a downgrade to below investment grade, under both hard trigger and soft trigger provisions, was approximately $412$638 million.
DTE Energy believes it will have sufficient operating flexibility, cash resources, and funding sources to maintain adequate amounts of liquidity and to meet future operating cash and capital expenditure needs. However, virtually all of DTE Energy's businesses are capital intensive, or require access to capital, and the inability to access adequate capital could adversely impact earnings and cash flows.
See Notes 8, 9, 13, 15,10, 14, 16, 18, and 1820 to the Consolidated Financial Statements in Item 8 of this Report, "Regulatory Matters",Matters," "Income Taxes",Taxes," "Long-Term Debt",Debt," "Short-Term Credit Arrangements and Borrowings",Borrowings," "Commitments and Contingencies," and "Retirement Benefits and Trusteed Assets".Assets," respectively.


Contractual Obligations
The following table details DTE Energy's, including DTE Electric's, contractual obligations for debt redemptions, leases, purchase obligations, and other long-term obligations as of December 31, 2015:2018:
Total 2016 2017-2018 2019-2020 2021 and BeyondTotal 2019 2020-2021 2022-2023 2024 and Thereafter
(In millions)(In millions)
Long-term debt:                  
Mortgage bonds, notes, and other (a)$8,820
 $465
 $416
 $1,115
 $6,824
$12,566
 $1,495
 $1,144
 $1,793
 $8,134
Junior subordinated debentures(b)480
 
 
 
 480
1,180
 
 
 
 1,180
Capital lease obligations24
 9
 12
 3
 
11
 4
 7
 
 
Interest7,022
 475
 756
 754
 5,037
10,340
 556
 1,016
 929
 7,839
Stock purchase contract33
 33
 
 
 
Operating leases197
 37
 55
 34
 71
154
 42
 48
 19
 45
Electric, gas, fuel, transportation, and storage purchase obligations (b)6,097
 1,918
 1,542
 575
 2,062
Long-term DTE Electric renewable energy power purchase agreements (c)(d)1,379
 82
 165
 165
 967
Other long-term obligations (e)(f)(g)126
 38
 64
 10
 14
Electric, gas, fuel, transportation, and storage purchase obligations(c)
5,509
 2,216
 1,465
 591
 1,237
Long-term DTE Electric renewable energy power purchase agreements(d)(e)
1,133
 100
 162
 162
 709
Other long-term obligations(f)(g)(h)
715
 375
 326
 7
 7
Total obligations$24,145
 $3,024
 $3,010
 $2,656
 $15,455
$31,641
 $4,821
 $4,168
 $3,501
 $19,151

(a)Excludes $15$16 million of unamortized debt discount on debt.and $73 million of unamortized debt issuance costs.
(b)
Excludes $35 million of unamortized debt issuance costs.
(c)Excludes amounts associated with full requirements contracts where no stated minimum purchase volume is required.
(c)(d)The agreements represent the minimum settlementsobligations with suppliers for renewable energy and renewable energy credits under existing contract terms which expire from 2030 through 2035. DTE Electric's share of plant output ranges from 44%29% to 100%.
(d)(e)Excludes a power purchase agreement with a non-utility affiliate of DTE Energy.
(e)(f)Includes liabilities for unrecognized tax benefits of $3$10 million.
(f)(g)Excludes other long-term liabilities of $138$172 million not directly derived from contracts or other agreements.
(g)(h)At December 31, 2015,2018, DTE Energy met the minimum pension funding levels required under the Employee Retirement Income Security Act of 1974 (ERISA) and the Pension Protection Act of 2006 for the defined benefit pension plans. DTE Energy may contribute more than the minimum funding requirements for the pension plans and may also make contributions to the other postretirement benefit plans; however, these amounts are not included in the table above as such amounts are discretionary. Planned funding levels are disclosed in the Capital"Capital Resources and LiquidityLiquidity" and Critical"Critical Accounting EstimatesEstimates" sections herein and in Note 1820 to the Consolidated Financial Statements in Item 8 of this Report, "Retirement Benefits and Trusteed Assets".Assets."

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Credit Ratings
Credit ratings are intended to provide banks and capital market participants with a framework for comparing the credit quality of securities and are not a recommendation to buy, sell, or hold securities. DTE Energy, DTE Electric, and DTE Gas' credit ratings affect their costs of capital and other terms of financing, as well as their ability to access the credit and commercial paper markets. DTE Energy, DTE Electric, and DTE Gas' management believes that the current credit ratings provide sufficient access to capital markets. However, disruptions in the banking and capital markets not specifically related to DTE Energy, DTE Electric, and DTE Gas may affect their ability to access these funding sources or cause an increase in the return required by investors.
As part of the normal course of business, DTE Electric, DTE Gas, and various non-utility subsidiaries of DTE Energy routinely enter into physical or financially settled contracts for the purchase and sale of electricity, natural gas, coal, capacity, storage, and other energy-related products and services. Certain of these contracts contain provisions which allow the counterparties to request that DTE Energy posts cash or letters of credit in the event that the senior unsecured debt rating of DTE Energy is downgraded below investment grade. The amount of such collateral which could be requested fluctuates based upon commodity prices and the provisions and maturities of the underlying transactions and could be substantial. Also, upon a downgrade below investment grade, DTE Energy, DTE Electric, and DTE Gas could have restricted access to the commercial paper market, and if DTE Energy is downgraded below investment grade, the non-utility businesses, especially the Energy Trading and Power and Industrial Projects segments, could be required to restrict operations due to a lack of available liquidity. A downgrade below investment grade could potentially increase the borrowing costs of DTE Energy, DTE Electric, and DTE Gas and their subsidiaries and may limit access to the capital markets. The impact of a downgrade will not affect DTE Energy, DTE Electric, and DTE Gas' ability to comply with existing debt covenants. While DTE Energy, DTE Electric, and DTE Gas currently do not anticipate such a downgrade, they cannot predict the outcome of current or future credit rating agency reviews.
In February 2016, based on DTE Energy's strong and predictable earnings and cash flow, Fitch upgraded DTE Energy's unsecured debt rating from 'BBB' to 'BBB+' and upgraded DTE Electric's secured debt rating from 'A' to 'A+'.

CRITICAL ACCOUNTING ESTIMATES
The preparation of the Registrants' Consolidated Financial Statements in conformity with generally accepted accounting principles requires that management apply accounting policies and make estimates and assumptions that affect results of operations and the amounts of assets and liabilities reported in the Consolidated Financial Statements. The Registrants' management believes that the areas described below require significant judgment in the application of accounting policy or in making estimates and assumptions in matters that are inherently uncertain and that may change in subsequent periods. Additional discussion of these accounting policies can be found in the Combined Notes to Consolidated Financial Statements in Item 8 of this Report.
Regulation
A significant portion of the Registrants' businesses are subject to regulation. This results in differences in the application of generally accepted accounting principles between regulated and non-regulated businesses. DTE Electric and DTE Gas are required to record regulatory assets and liabilities for certain transactions that would have been treated as revenue or expense in non-regulated businesses. Future regulatory changes or changes in the competitive environment could result in the discontinuance of this accounting treatment for regulatory assets and liabilities for some or all of the Registrants' businesses. The Registrants' management believes that currently available facts support the continued use of regulatory assets and liabilities and that all regulatory assets and liabilities are recoverable or refundable in the current rate environment.
See Note 89 to the Consolidated Financial Statements in Item 8 of this Report, "Regulatory Matters".Matters."
Derivatives
Derivatives are generally recorded at fair value and shown as Derivative assets or liabilities. Changes in the fair value of the derivative instruments are recognized in earnings in the period of change. The normal purchases and normal sales exception requires, among other things, physical delivery in quantities expected to be used or sold over a reasonable period in the normal course of business. Contracts that are designated as normal purchases and normal sales are not recorded at fair value. Substantially all of the commodity contracts entered into by DTE Electric and DTE Gas meet the criteria specified for this exception.

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Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in a principal or most advantageous market. Fair value is a market-based measurement that is determined based on inputs, which refer broadly to assumptions that market participants use in pricing assets andor liabilities. These inputs can be readily observable, market corroborated, or generally unobservable inputs. The Registrants' management makesRegistrants make certain assumptions it believesthey believe that market participants would use in pricing assets andor liabilities, including assumptions about risk, and the risks inherent in the inputs to valuation techniques. Credit risk of the Registrants and their counterparties is incorporated in the valuation of the assets and liabilities through the use of credit reserves, the impact of which was immaterial at December 31, 20152018 and 2014.2017. The Registrants' management believes it usesRegistrants believe they use valuation techniques that maximize the use of observable market-based inputs and minimize the use of unobservable inputs.
The fair values the Registrants calculate for their derivatives may change significantly as inputs and assumptions are updated for new information. Actual cash returns realized on derivatives may be different from the results the Registrants estimate using models. As fair value calculations are estimates based largely on commodity prices, the Registrants perform sensitivity analyses on the fair values of forward contracts. See the sensitivity analysis in Item 7A. of this report, "Quantitative and Qualitative Disclosures About Market Risk".Risk." See also the Fair Value"Fair Value" section herein.
See Notes 1112 and 1213 to the Consolidated Financial Statements in Item 8 of this Report, "Fair Value" and "Financial and Other Derivative Instruments",Instruments," respectively.
Allowance for Doubtful Accounts
The Registrants each establish an allowance for doubtful accounts based on historical losses and their respective management's assessment of existing economic conditions, customer trends, and other factors. The allowance for doubtful accounts for DTE Electric and DTE Gas is calculated using the aging approach that utilizes rates developed in reserve studies and applies these factors to past due receivable balances. The Registrants believe the allowance for doubtful accounts is based on reasonable estimates.
Asset Impairments
Goodwill
Certain of DTE Energy's reporting units have goodwill or allocated goodwill resulting from business combinations. DTE Energy performs an impairment test for each of the reporting units with goodwill annually or whenever events or circumstances indicate that the value of goodwill may be impaired.


In performing Step 1 of the impairment test, DTE Energy compares the fair value of the reporting unit to its carrying value including goodwill. If the carrying value including goodwill were to exceed the fair value of a reporting unit, Step 2 of the test would be performed. Step 2 of the impairment test requires the carrying value of goodwill to be reduced to its fair value, if lower, as of the test date.
For Step 1 of the test, DTE Energy estimates the reporting unit's fair value using standard valuation techniques, including techniques which use estimates of projected future results and cash flows to be generated by the reporting unit. Such techniques generally include a terminal value that utilizes an earnings multiple or assumed long-term growth rate approach, which incorporates the current market values of comparable entities.entities or management's assumptions regarding sustainable long-term growth of the reporting units, respectively. These cash flow valuations involve a number of estimates that require broad assumptions and significant judgment by management regarding future performance. DTE Energy also employs market-based valuation techniques to test the reasonableness of the indications of value for the reporting units determined under the cash flow technique.
DTE Energy performs an annual impairment test each October. In between annual tests, DTE Energy monitors its estimates and assumptions regarding estimated future cash flows, including the impact of movements in market indicators in future quarters, and will update the impairment analyses if a triggering event occurs. While DTE Energy believes the assumptions are reasonable, actual results may differ from projections. To the extent projected results or cash flows are revised downward, the reporting unit may be required to write down all or a portion of its goodwill, which would adversely impact DTE Energy's earnings.

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DTE Energy performed its annual impairment test as of October 1, 20152018 and determined that the estimated fair value of each reporting unit exceeded its carrying value, and no impairment existed. As part of the annual impairment test, DTE Energy also compared the aggregate fair value of the reporting units to its overall market capitalization. The implied premium of the aggregate fair value over market capitalization is likely attributable to an acquisition control premium (the price in excess of a stock's market price that investors typically pay to gain control of an entity).
The results of the test and key estimates that were incorporated are as follows as of the October 1, 20152018 valuation date:
Reporting Unit Goodwill Fair Value Reduction % (a) Discount Rate Terminal Multiple (b) Valuation Methodology (c) Goodwill 
Fair Value Reduction %(a)
 Discount Rate 
Terminal Multiple(b)
 
Valuation Methodology(c)
 (In millions)      (In millions)     
Electric $1,208
 37% 7% 9.5x DCF, assuming stock sale $1,208
 35% 6% 10.0x DCF, assuming stock sale
Gas 743
 31% 6% 10.5x DCF, assuming stock sale 743
 30% 7% 12.0x DCF, assuming stock sale
Gas Storage and Pipelines 24
 74% 8% 11.0x DCF, assuming asset sale 299
 19% 7% 
n/a(d)
 DCF, assuming asset sale
Power and Industrial Projects (d)(e) 26
 23% 7% 10.0x DCF, assuming asset sale (e) 26
 18% 6% 9.0x 
DCF, assuming asset sale(f)
Energy Trading 17
 47% 10% n/a (f) DCF, assuming asset sale 17
 56% 12% 
n/a(g)
 DCF, assuming asset sale
 $2,018
      $2,293
     

(a)Percentage by which the fair value of equity of the reporting unit would need to decline to equal its carrying value, including goodwill.
(b)Multiple of enterprise value (sum of debt plus equity value) to earnings before interest, taxes, depreciation, and amortization (EBITDA).
(c)Discounted cash flows (DCF) incorporated 2016-20202019-2023 projected cash flows plus a calculated terminal value.
(d)Due to the nature of the projected cash flows for Gas Storage and Pipelines, DTE Energy capitalized the terminal year cash flows at the weighted average cost of capital (WACC) less an assumed long-term growth rate of 3.0% in lieu of applying a terminal EBITDA multiple.
(e)Power and Industrial Projects excludes the Biomass reporting unit, as this unit has no allocated goodwill.
(e)(f)Asset sales were assumed, except for Power and Industrial Projects' reduced emissions fuels projects, which assumed stock sales.
(f)(g)Due to lack of market comparable information for Energy Trading, DTE Energy capitalized the terminal year cash flows at the weighted average cost of capital (WACC)WACC in lieu of applying a terminal EBITDA multiple.
DTE Energy identified a goodwill impairment test trigger for its Power and Industrial Projects reporting unit during the fourth quarter of 2015. The trigger related to the closure of the Shenango coke battery plant and the testing for recoverability of the long-lived asset for another coke battery in response to a sharp downturn in the North American steel industry. Accordingly, DTE Energy performed an interim goodwill impairment test for the Power and Industrial Projects reporting unit as of November 30, 2015 using updated cash flow and discount rate assumptions. As compared to the annual test, the interim valuation was negatively impacted by the projected lower value expected to be realized from DTE Energy's steel-related projects during 2016 and a higher discount rate. The fair value reduction percentage decreased from 23% to 16%. The fair value of the reporting unit exceeded its carrying value including goodwill. Therefore, the reporting unit passed Step 1 of the impairment test. No other triggers were identified during the fourth quarter of 2015. In 2016, DTE Energy will continue to monitor the North American steel industry for other events that may indicate the fair value of goodwill is below the carrying value of the Power and Industrial Projects reporting unit.
Long-Lived Assets
The Registrants evaluate the carrying value of long-lived assets, excluding goodwill, when circumstances indicate that the carrying value of those assets may not be recoverable. Conditions that could have an adverse impact on the cash flows and fair value of the long-lived assets are deteriorating business climate, condition of the asset, or plans to dispose of the asset before the end of its useful life. The review of long-lived assets for impairment requires significant assumptions about operating strategies and estimates of future cash flows, which require assessments of current and projected market conditions. An impairment evaluation is based on an undiscounted cash flow analysis at the lowest level for which independent cash flows of long-lived assets can be identified from other groups of assets and liabilities. Impairment may occur when the carrying value of the asset exceeds the future undiscounted cash flows. When the undiscounted cash flow analysis indicates a long-lived asset is not recoverable, the amount of the impairment loss is determined by measuring the excess of the long-lived asset over its fair value. An impairment would require the Registrants to reduce both the long-lived asset and current period earnings by the amount of the impairment, which would adversely impact their earnings.
During the fourth quarter of 2015, DTE Energy announced the closure of the Shenango coke battery plant. As a result of the closure, long-lived assets with a carrying value of $96 million were fully impaired.

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In connection with the closure of the Shenango coke battery plant, DTE Energy reviewed another coke battery asset for events and circumstances that indicate the long-lived asset, of approximately $108 million, within the Power and Industrial Projects reporting unit might be impaired. However, DTE Energy’s estimate of undiscounted cash flows indicated that such carrying amounts were expected to be recovered. DTE Energy will continue to monitor the assumptions used in this analysis. Further deterioration of the steel industry could lead to a future impairment of the asset.
Pension and Other Postretirement Costs
DTE Energy sponsors defined benefit pension plans and other postretirement benefit plans for eligible employees of the Registrants. The measurement of the plan obligations and cost of providing benefits under these plans involve various factors, including numerous assumptions and accounting elections. When determining the various assumptions that are required, DTE Energy considers historical information as well as future expectations. The benefit costs are affected by, among other things, the actual rate of return on plan assets, the long-term expected return on plan assets, the discount rate applied to benefit obligations, the incidence of mortality, the expected remaining service period of plan participants, level of compensation and rate of compensation increases, employee age, length of service, the anticipated rate of increase of health care costs, benefit plan design changes, and the level of benefits provided to employees and retirees. Pension and other postretirement benefit costs attributed to the segments are included with labor costs and ultimately allocated to projects within the segments, some of which are capitalized.
DTE Energy had pension costs of $221$148 million in 2015, $1792018, $172 million in 2014,2017, and $228$167 million in 2013.2016. Other postretirement benefit credits were $99$36 million in 2015, $1232018, $31 million in 2014,2017, and $42$111 million in 2013.2016. Pension costs and other postretirement benefit credits for 2015 are2018 were calculated based upon a number ofseveral actuarial assumptions, including an expected long-term rate of return on plan assets of 7.75%7.50% for the pension plans and 8.00%7.75% for the other postretirement benefit plans. In developing the expected long-term rate of return assumptions, DTE Energy evaluated asset class risk and return expectations, as well as inflation assumptions. Projected returns are based on broad equity, bond, and other markets. DTE Energy's 20162019 expected long-term rate of return on pension plan assets is based on an asset allocation assumption utilizing active investment management of 47%35% in equity markets, 25%42% in fixed income markets, including long duration bonds, and 28%23% invested in other assets. DTE Energy's 20162019 expected long-term rate of return on other postretirement plan assets is based on an asset allocation assumption utilizing active investment management of 41%39% in equity markets, 25%28% in fixed income markets, and 34%33% invested in other assets. Because of market volatility, DTE Energy periodically reviews the asset allocation and rebalances the portfolio when considered appropriate. Given market conditions and financial market risk considerations, DTE Energy is maintaininglowering its long-term rate of return assumptionsassumption for the pension plans to 7.30% and maintaining the other postretirement plans at 7.75% and 8.00%, respectively, for 2016.2019. DTE Energy believes these rates are reasonable assumptions for the long-term raterates of return on the planplans' assets for 20162019 given its investment strategy.their respective asset allocations and DTE's capital market expectations. DTE Energy will continue to evaluate the actuarial assumptions, including its expected rate of return, at least annually.
DTE Energy calculates the expected return on pension and other postretirement benefit plan assets by multiplying the expected return on plan assets by the market-related value (MRV) of plan assets at the beginning of the year, taking into consideration anticipated contributions and benefit payments that are to be made during the year. Current accounting rules provide that the MRV of plan assets can be either fair value or a calculated value that recognizes changes in fair value in a systematic and rational manner over not more than five years. For the pension plans, DTE Energy uses a calculated value when determining the MRV of the pension plan assets and recognizes changes in fair value over a three-year period. Accordingly, the future value of assets will be impacted as previously deferred gains or losses are recognized. Financial marketsNegative asset performance in 2015 detracted from DTE Energy's investment performance resulting2018 resulted in unrecognized net losses. As of December 31, 2015,2018, DTE Energy had $175$248 million of cumulative losses related to investment performance in 2018 and 2017, that remain to bewere not yet recognized in the calculation of the MRV of pension assets related to investment performance in 2015 and 2014.assets. For the other postretirement benefit plans, DTE Energy uses fair value when determining the MRV of other postretirement benefit plan assets, therefore all investment gains and losses have been recognized in the calculation of MRV for these plans.
The discount rate that DTE Energy utilizes for determining future pension and other postretirement benefit obligations is based on a yield curve approach and a review of bonds that receive one of the two highest ratings given by a recognized rating agency. The yield curve approach matches projected pension plan and other postretirement benefit payment streams with bond portfolios reflecting actual liability duration unique to the plans. The discount rate determined on this basis was 4.50%4.40% for the pension plans and 4.50% for the other postretirement plans at December 31, 20152018 compared to 4.12%3.70% for the pension plans and 4.10% for the other postretirement plans at December 31, 2014.2017.

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The mortality assumptions that DTE Energy used to determinechanged the pension and other postretirement benefit obligationsmortality assumption as of December 31, 2015, were2018 to reflect the updated to incorporate the MP-2015 generationalMP-2018 projection scale, issued byalong with the Societyactual experience and credibility of Actuaries in 2015.each population. The mortality assumptions used at December 31, 20152018 are the RP-2014 mortality table projected back to 2006 using the Scale MP-2014, projected forward to 2015 using the Scale MP-2017 and projected beyond 2015 using the Scale MP-2018 with variationsgenerational projection. The base mortality tables vary by type of plan, and participant’semployee's union status and employment status, projected backwith additional adjustments to 2006 using Scale MP-2014reflect the actual experience and projected forward using Scale MP-2015.credibility of each population.


DTE Energy estimates that the 20162019 total pension costs will approximate $175be approximately $100 million in 2019, compared to $221$148 million in 2015,2018. The reduction in total pension costs is primarily due to higherupdated demographic assumptions and favorable discount rates, and changes to the mortality tables, partially offset by less than expected 2015lower asset returns. The 20162019 other postretirement benefit credit will approximate $110be approximately $45 million compared to $99$36 million in 2015 due to higher discount rate, changes to the mortality tables, and favorable retiree medical utilization trends, partially offset by lower than expected financial market returns.2018.
The health care trend rates for DTE Energy assume 6.25%6.75% for pre-65 participants and 6.75%7.25% for post-65 participants for 2016,2019, trending down to 4.50% for both pre-65 and post-65 participants in 2027.2031.
Future actual pension and other postretirement benefit costs (credits)or credits will depend on future investment performance, changes in future discount rates, and various other factors related to plan design.
Lowering the expected long-term rate of return on the plan assets by one percentage point would have increased the 20152018 pension costs by approximately $38$44 million. Lowering the discount rate and the salary increase assumptions by one percentage point would have increased the 20152018 pension costs by approximately $21$24 million. Lowering the expected long-term rate of return on plan assets by one percentage point would have decreased the 20152018 other postretirement credit by approximately $15$18 million. Lowering the discount rate assumption by one percentage point would have decreased the 20152018 other postretirement credit by approximately $27 million. Lowering the health care cost trend assumptions by one percentage point would have increased the other postretirement credit for 20152018 by approximately $6$4 million.
The value of the qualified pension and other postretirement benefit plan assets was $5.4$6.0 billion at December 31, 20152018 and $5.5$6.5 billion at December 31, 2014.2017. At December 31, 2015,2018, DTE Energy's qualified pension plans were underfunded by $1 billion$720 million and its other postretirement benefit plans were underfundedoverfunded by $230$44 million. The 2015 funding levels generally increased due to increased discount rates, a change inIn 2018, the mortality tables, andfunded status of the pension plans improved as plan sponsor contributions and an increase in discount rates were partially offset by lower than expected financial marketnegative asset returns. The funded status of the other postretirement benefit plans improved as an increase in discount rates and favorable healthcare experience were partially offset by negative asset returns.
Pension and other postretirement costs and pension cash funding requirements may increase in future years without typical returns in the financial markets. DTE Energy made contributions to its qualified pension plans of $177$175 million in 20152018 and $188$223 million in 2014.2017. At the discretion of management, consistent with the Pension Protection Act of 2006, and depending upon financial market conditions, DTE Energy anticipates making contributions to its qualified pension plans of up to $180$150 million in 20162019 and up to $960$700 million over the next five years. DTE Energy madedid not make other postretirement benefit plan contributions of $199 million in 2015 and $24 million in 2014.2018 or 2017. DTE Energy is required by orders issued by the MPSC to make other postretirement benefit contributions at least equal to the amounts included in the utilities' base rates. As a result, DTE Energy anticipatesdoes not anticipate making up to $20 million ofany contributions to its other postretirement plans in 2016 and2019 or over the next five years. The planned pension contributions will be made in cash and/or a combination of cash and DTE Energy common stock.
See Note 1820 to the Consolidated Financial Statements in Item 8 of this Report, "Retirement Benefits and Trusteed Assets".Assets."
Legal Reserves
The Registrants are involved in various legal proceedings, claims, and litigation arising in the ordinary course of business. The Registrants regularly assess their liabilities and contingencies in connection with asserted or potential matters, and establish reserves when appropriate. Legal reserves are based upon the Registrants' management’s assessment of pending and threatened legal proceedings and claims against the Registrants.

45



Accounting for Tax Obligations
The Registrants are required to make judgments regarding the potential tax effects of various financial transactions and results of operations in order to estimate their obligations to taxing authorities. The Registrants account for uncertain income tax positions using a benefit recognition model with a two-step approach, a more-likely-than-not recognition criterion, and a measurement attribute that measures the position as the largest amount of tax benefit that is greater than 50% likely of being realized upon ultimate settlement. If the benefit does not meet the more likely than not criteria for being sustained on its technical merits, no benefit will be recorded. Uncertain tax positions that relate only to timing of when an item is included on a tax return are considered to have met the recognition threshold. The Registrants also have non-income tax obligations related to property, sales and use, and employment-related taxes, and ongoing appeals related to these tax matters.


Accounting for tax obligations requires judgments, including assessing whether tax benefits are more likely than not to be sustained, and estimating reserves for potential adverse outcomes regarding tax positions that have been taken. The Registrants also assess their ability to utilize tax attributes, including those in the form of carry-forwards, for which the benefits have already been reflected in the Consolidated Financial Statements. The Registrants believe the resulting tax reserve balances as of December 31, 20152018 and 20142017 are appropriate. The ultimate outcome of such matters could result in favorable or unfavorable adjustments to the Registrants' Consolidated Financial Statements, and such adjustments could be material.
See Note 910 to the Consolidated Financial Statements in Item 8 of this Report, "Income Taxes".Taxes."
NEW ACCOUNTING PRONOUNCEMENTS
See Note 3 to the Consolidated Financial Statements in Item 8 of this Report, "New Accounting Pronouncements".Pronouncements."
FAIR VALUE
Derivatives are generally recorded at fair value and shown as Derivative assets or liabilities. Contracts DTE Energy typically classifies as derivative instruments include power, natural gas, oil, and certain coal forwards, futures, options and swaps, and foreign currency exchange contracts. Items DTE Energy does not generally account for as derivatives include natural gas inventory, pipeline transportation contracts, renewable energy credits, and storage assets. See Notes 1112 and 1213 to the Consolidated Financial Statements in Item 8 of this Report, "Fair Value" and "Financial and Other Derivative Instruments",Instruments," respectively.
The tables below do not include the expected earnings impact of non-derivative natural gas storage, transportation, certain power contracts, and renewable energy credits which are subject to accrual accounting. Consequently, gains and losses from these positions may not match with the related physical and financial hedging instruments in some reporting periods, resulting in volatility in the Registrants' reported period-by-period earnings; however, the financial impact of the timing differences will reverse at the time of physical delivery and/or settlement.
The Registrants manage their MTM risk on a portfolio basis based upon the delivery period of their contracts and the individual components of the risks within each contract. Accordingly, the Registrants record and manage the energy purchase and sale obligations under their contracts in separate components based on the commodity (e.g. electricity or natural gas), the product (e.g. electricity for delivery during peak or off-peak hours), the delivery location (e.g. by region), the risk profile (e.g. forward or option), and the delivery period (e.g. by month and year).
The Registrants have established a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value in three broad levels. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). For further discussion of the fair value hierarchy, see Note 1112 to the Consolidated Financial Statements in Item 8 of this Report, "Fair Value".Value."

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The following tables providetable provides details on changes in the Registrants'DTE Energy's MTM net asset (or liability) position during 2015:position:
TotalTotal
(In millions)(In millions)
MTM at December 31, 2014$87
MTM at December 31, 2017$8
Reclassified to realized upon settlement(45)74
Changes in fair value recorded to income(28)(81)
Amounts recorded to unrealized income(73)(7)
Changes in fair value recorded in regulatory liabilities12
9
Change in collateral held by (for) others16
Option premiums paid (received) and other(2)
MTM at December 31, 2015$40
Change in collateral(30)
Amounts recorded in Other comprehensive income, pretax(3)
MTM at December 31, 2018$(23)


The table below shows the maturity of the Registrants'DTE Energy's MTM positions. The positions from 20192022 and beyond principally represent longer tenor gas structured transactions:
Source of Fair Value 2016 2017 2018 2019 and Beyond Total Fair Value 2019 2020 2021 2022 and Beyond Total Fair Value
 (In millions) (In millions)
Level 1 $(13) $(14) $(2) $4
 $(25) $4
 $(1) $(1) $
 $2
Level 2 21
 7
 5
 2
 35
 20
 8
 3
 5
 36
Level 3 41
 6
 1
 (52) (4) 21
 (7) (11) (47) (44)
MTM before collateral adjustments $49
 $(1) $4
 $(46) 6
 $45
 $
 $(9) $(42) (6)
Collateral adjustments         34
         (17)
MTM at December 31, 2015         $40
MTM at December 31, 2018         $(23)

Item 7A. Quantitative and Qualitative Disclosures About Market Risk
Market Price Risk
The Electric and Gas businesses have commodity price risk, primarily related to the purchases of coal, natural gas, uranium, and electricity. However, the Registrants do not bear significant exposure to earnings risk, as such changes are included in the PSCR and GCR regulatory rate-recovery mechanisms. In addition, changes in the price of natural gas can impact the valuation of lost and stolen gas, storage sales, and transportation services revenue at the Gas segment. The Gas segment manages its market price risk related to storage sales revenue primarily through the sale of long-term storage contracts. The Registrants are exposed to short-term cash flowsflow or liquidity risk as a result of the time differential between actual cash settlements and regulatory rate recovery.
DTE Energy's Gas Storage and Pipelines business segment has exposure to natural gas price fluctuations which impact the pricing for natural gas storage, gathering, and transportation. DTE Energy manages its exposure through the use of short, medium, and long-term storage, gathering, and transportation contracts.
DTE Energy's Power and Industrial Projects business segment is subject to electricity, natural gas, and coal product price risk. DTE Energy manages its exposure to commodity price risk through the use of long-term contracts.
DTE Energy's Energy Trading business segment has exposure to electricity, natural gas, coal, crude oil, heating oil, and foreign currency exchange price fluctuations. These risks are managed by the energy marketing and trading operations through the use of forward energy, capacity, storage, options, and futures contracts, within pre-determined risk parameters.

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Credit Risk
Bankruptcies
CertainDTE Energy's Power and Industrial Projects segment holds ownership interests in, and operates, five generating plants that sell electric output from renewable sources under long-term power purchase agreements with PG&E. PG&E filed for Chapter 11 bankruptcy protection on January 29, 2019. As of December 31, 2018, uncollected pre-petition accounts receivable from PG&E were approximately $12 million. Currently, PG&E has been paying amounts owed in a timely manner and its account is current. As of December 31, 2018, DTE Energy has not recorded a reserve related to the pre-petition receivables.
As of December 31, 2018, the book value of long-lived assets used in producing electric output for sale to PG&E was approximately $106 million. As of December 31, 2018, DTE Energy performed an impairment analysis on its long-lived assets in accordance with ASC 360, Property, Plant and Equipment. Based on its undiscounted cash flow projections, DTE Energy determined that it did not have an impairment loss as of December 31, 2018. DTE Energy’s assumptions and conclusions may change, and it could have impairment losses if any of the Registrants' customersterms of the contracts are not honored by PG&E or the contracts are rejected through the bankruptcy process.


The Power and suppliersIndustrial Projects segment also has equity investments, including a note receivable, of approximately $77 million in entities that sell power to PG&E. DTE Energy has determined that it does not have filed foran other than temporary decline in its equity investments as described in ASC 323, Investments-Equity Method and Joint Ventures. DTE Energy’s assumptions and conclusions may change in the future, and it could have an impairment loss if certain facilities are not utilized as currently anticipated or the contracts are rejected through the bankruptcy protection under the U.S. Bankruptcy Code. process.
Other
The Registrants regularly review contingent matters relating to these customers and suppliers and their purchase and sale contracts and record provisions for amounts considered at risk of probable loss in the allowance for doubtful accounts. The Registrants believe their accrued amounts are adequate for probable loss.
Trading Activities
DTE Energy is exposed to credit risk through trading activities. Credit risk is the potential loss that may result if the trading counterparties fail to meet their contractual obligations. DTE Energy utilizes both external and internal credit assessments when determining the credit quality of trading counterparties.
The following table displays the credit quality of DTE Energy's trading counterparties as of December 31, 2015:2018:
Credit Exposure
Before Cash
Collateral
 Cash
Collateral
 Net Credit
Exposure
Credit Exposure
Before Cash
Collateral
 Cash
Collateral
 Net Credit
Exposure
(In millions)(In millions)
Investment Grade (a)          
A- and Greater$164
 $(2) $162
$348
 $
 $348
BBB+ and BBB230
 
 230
288
 
 288
BBB-56
 
 56
49
 
 49
Total Investment Grade450
 (2) 448
685
 
 685
Non-investment grade (b)7
 
 7
3
 
 3
Internally Rated — investment grade (c)238
 
 238
368
 (1) 367
Internally Rated — non-investment grade (d)21
 (4) 17
38
 (4) 34
Total$716
 $(6) $710
$1,094
 $(5) $1,089

(a)This category includes counterparties with minimum credit ratings of Baa3 assigned by Moody’s Investors Service (Moody’s) or BBB- assigned by Standard & Poor’s Rating Group, a division of McGraw-Hill Companies, Inc. (Standard & Poor’s). The five largest counterparty exposures, combined, for this category represented approximately 24%16% of the total gross credit exposure.
(b)This category includes counterparties with credit ratings that are below investment grade. The five largest counterparty exposures, combined, for this category represented less than 1% of the total gross credit exposure.
(c)This category includes counterparties that have not been rated by Moody’s or Standard & Poor’s, but are considered investment grade based on DTE Energy’s evaluation of the counterparty’s creditworthiness. The five largest counterparty exposures, combined, for this category represented approximately 13%14% of the total gross credit exposure.
(d)This category includes counterparties that have not been rated by Moody’s or Standard & Poor’s, and are considered non-investment grade based on DTE Energy’s evaluation of the counterparty’s creditworthiness. The five largest counterparty exposures, combined, for this category represented approximately 3%2% of the total gross credit exposure.
Other
The Registrants engage in business with customers that are non-investment grade. The Registrants closely monitor the credit ratings of these customers and, when deemed necessary and permitted under the tariffs, request collateral or guarantees from such customers to secure their obligations.
Interest Rate Risk
DTE Energy is subject to interest rate risk in connection with the issuance of debt. In order to manage interest costs, DTE Energy may use treasury locks and interest rate swap agreements. DTE Energy's exposure to interest rate risk arises primarily from changes in U.S. Treasury rates, commercial paper rates, and London Inter-Bank Offered Rates (LIBOR).LIBOR. As of December 31, 2015,2018, DTE Energy had a floating rate debt-to-total debt ratio of approximately 5.2%4.3%.

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Foreign Currency Exchange Risk
DTE Energy has foreign currency exchange risk arising from market price fluctuations associated with fixed priced contracts. These contracts are denominated in Canadian dollars and are primarily for the purchase and sale of natural gas and power, as well as for long-term transportation capacity. To limit DTE Energy's exposure to foreign currency exchange fluctuations, DTE Energy has entered into a series of foreign currency exchange forward contracts through June 2020.2023.
Summary of Sensitivity Analyses
The RegistrantsSensitivity analyses were performed sensitivity analyses on the fair values of commodity contracts for DTE Energy and long-term debt obligations and foreign currency exchange forward contracts.for the Registrants. The commodity contracts and foreign currency exchange risk listed below principally relate to energy marketing and trading activities. The sensitivity analysisanalyses involved increasing and decreasing forward prices and rates at December 31, 20152018 and 20142017 by a hypothetical 10% and calculating the resulting change in the fair values.
The results of the sensitivity analysis calculations as of December 31, 2015 and 2014:analyses:
 
Assuming a
10% Increase in Prices/Rates
 
Assuming a
10% Decrease in Prices/Rates
  
Assuming a
10% Increase in Prices/Rates
 
Assuming a
10% Decrease in Prices/Rates
 
 As of December 31, As of December 31,  As of December 31, As of December 31, 
Activity 2015 2014 2015 2014 Change in the Fair Value of 2018 2017 2018 2017 Change in the Fair Value of
 (In millions)  (In millions) 
Gas contracts $(5) $(4) $5
 $5
 Commodity contracts $8
 $
 $(8) $
 Commodity contracts
Power contracts $16
 $
 $(16) $
 Commodity contracts $10
 $5
 $(10) $(7) Commodity contracts
Oil contracts $1
 $
 $(1) $
 Commodity contracts
Interest rate risk — DTE Energy $(372) $(336) $395
 $356
 Long-term debt $(596) $(576) $625
 $581
 Long-term debt
Interest rate risk — DTE Electric $(225) $(202) $243
 $216
 Long-term debt $(277) $(246) $300
 $263
 Long-term debt
For further discussion of market risk, see Management's Discussion and Analysis in Item 7 of this Report and Note 1213 to the Consolidated Financial Statements in Item 8 of this Report, "Financial and Other Derivative Instruments".Instruments."


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Item 8. Financial Statements and Supplementary Data
The following Consolidated Financial Statements and financial statement schedules are included herein:
 Page
Financial Statement Schedule 

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DTE Energy — Controls and Procedures
(a) Evaluation of disclosure controls and procedures
Management of DTE Energy carried out an evaluation, under the supervision and with the participation of DTE Energy’sEnergy's Chief Executive Officer (CEO) and Chief Financial Officer (CFO), of the effectiveness of the design and operation of DTE Energy's disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) as of December 31, 2015,2018, which is the end of the period covered by this report. Based on this evaluation, DTE Energy’sEnergy's CEO and CFO have concluded that such disclosure controls and procedures are effective in providing reasonable assurance that information required to be disclosed by DTE Energy in reports that it files or submits under the Exchange Act (i) is recorded, processed, summarized, and reported within the time periods specified in the U.S. Securities and Exchange Commission's rules and forms and (ii) is accumulated and communicated to DTE Energy’sEnergy's management, including its CEO and CFO, as appropriate to allow timely decisions regarding required disclosure. Due to the inherent limitations in the effectiveness of any disclosure controls and procedures, management cannot provide absolute assurance that the objectives of its disclosure controls and procedures will be attained.
(b) Management’s report on internal control over financial reporting
Management of DTE Energy is responsible for establishing and maintaining adequate internal control over financial reporting as such term is defined in Exchange Act Rules 13a-15(f) and 15d-15(f). Internal control over financial reporting is a process designed by, or under the supervision of, DTE Energy's CEO and CFO, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles.
Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.
Management of DTE Energy has assessed the effectiveness of DTE Energy’s internal control over financial reporting as of December 31, 2015.2018. In making this assessment, management used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (2013 COSO) in Internal Control - Integrated Framework. Based on this assessment, management concluded that, as of December 31, 2015,2018, DTE Energy’s internal control over financial reporting was effective based on those criteria.
The effectiveness of DTE Energy’s internal control over financial reporting as of December 31, 20152018 has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm who also audited DTE Energy’s financial statements, as stated in their report which appears herein.
(c) Changes in internal control over financial reporting
There have been no changes in DTE Energy’sEnergy's internal control over financial reporting during the quarter ended December 31, 20152018 that have materially affected, or are reasonably likely to materially affect, DTE Energy’sEnergy's internal control over financial reporting.

51




REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM


To the Board of Directors and Shareholders of
DTE Energy Company

Opinions on the Financial Statements and Internal Control over Financial Reporting
In our opinion, the consolidated financial statements listed inWe have audited the accompanying index present fairly, in all material respects, theconsolidated statements of financial position of DTE Energy Company and its subsidiaries at(the “Company”) as of December 31, 20152018 and 2014, 2017 ,and the resultsrelated consolidated statements of their operations, of comprehensive income, of changes in equity and theirof cash flows for each of the three years in the period ended December 31, 20152018, including the related notes and schedule of valuation and qualifying accounts for each of the three years in the period ended December 31, 2018 listed in the accompanying index (collectively referred to as the “consolidated financial statements”).We also have audited the Company's internal control over financial reporting as of December 31, 2018, based on criteria established in Internal Control - Integrated Framework(2013)issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO).
In our opinion, the consolidatedfinancial statements referred to above present fairly, in all material respects, the financial position of the Company as of December 31, 2018and 2017, and the results of itsoperations and itscash flows for each of the three years in the period ended December 31, 2018 in conformity with accounting principles generally accepted in the United States of America. In addition, in our opinion, the financial statement schedule listed in the accompanying indexpresents fairly, in all material respects, the information set forth therein when read in conjunction with the related consolidatedfinancial statements. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2015,2018, based on criteria established in Internal Control - Integrated Framework 2013(2013)issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). COSO.
Basis for Opinions
The Company's management is responsible for these consolidated financial statements, and financial statement schedule, for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management’s reportReport on internal controlInternal Control over financial reporting.Financial Reporting. Our responsibility is to express opinions on these the Company’s consolidatedfinancial statements on the financial statement schedule, and on the Company's internal control over financial reporting based on our integrated audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) ("PCAOB") and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.
We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States).PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud, and whether effective internal control over financial reporting was maintained in all material respects.
Our audits of the consolidatedfinancial statements included performing procedures to assess the risks of material misstatement of the consolidatedfinancial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence supportingregarding the amounts and disclosures in the consolidatedfinancial statements, assessingstatements. Our audits also included evaluating the accounting principles used and significant estimates made by management, andas well as evaluating the overall presentation of the consolidatedfinancial statement presentation.statements. Our audit of internal control over financial reporting included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audits also included performing such other procedures as we considered necessary in the circumstances. We believe that our audits provide a reasonable basis for our opinions.


Definition and Limitations of Internal Control over Financial Reporting
A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (i) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.


/s/ PricewaterhouseCoopers LLP

Detroit, Michigan
February 10, 20167, 2019

52We have served as the Company’s auditor since 2008.




DTE Energy Company
Consolidated Statements of Operations
Year Ended December 31,Year Ended December 31,
2015 2014 20132018 2017 2016
(In millions, except per share amounts)(In millions, except per share amounts)
Operating Revenues          
Utility operations$6,238
 $6,884
 $6,643
$6,670
 $6,434
 $6,497
Non-utility operations4,099
 5,417
 3,018
7,542
 6,173
 4,133
10,337

12,301

9,661
14,212

12,607

10,630
          
Operating Expenses 
  
  
     
Fuel, purchased power, and gas — utility2,081
 2,407
 2,281
1,981
 1,881
 1,968
Fuel, purchased power, and gas — non-utility3,481
 4,615
 2,544
6,630
 5,283
 3,562
Operation and maintenance2,214
 2,204
 2,208
2,451
 2,270
 2,261
Depreciation and amortization852
 1,145
 1,094
1,124
 1,030
 976
Taxes other than income364
 352
 340
405
 391
 370
Asset (gains) losses and impairments, net106
 (12) (9)27
 41
 7
9,098
 10,711
 8,458
12,618
 10,896
 9,144
Operating Income1,239
 1,590
 1,203
1,594
 1,711
 1,486
          
Other (Income) and Deductions 
  
  
     
Interest expense450
 429
 436
559
 536
 472
Interest income(13) (10) (9)(12) (12) (20)
Non-operating retirement benefits, net37
 65
 41
Other income(209) (196) (201)(333) (268) (207)
Other expenses61
 92
 55
127
 103
 95
289
 315
 281
378
 424
 381
Income Before Income Taxes950
 1,275
 922
1,216
 1,287
 1,105
          
Income Tax Expense230
 364
 254
98
 175
 271
          
Net Income720
 911
 668
1,118
 1,112
 834
          
Less: Net Income (Loss) Attributable to Noncontrolling Interests(7) 6
 7
Less: Net Loss Attributable to Noncontrolling Interests(2) (22) (34)
          
Net Income Attributable to DTE Energy Company$727
 $905
 $661
$1,120
 $1,134
 $868
          
Basic Earnings per Common Share          
Net Income Attributable to DTE Energy Company$4.05
 $5.11
 $3.76
$6.18
 $6.32
 $4.84
          
Diluted Earnings per Common Share          
Net Income Attributable to DTE Energy Company$4.05
 $5.10
 $3.76
$6.17
 $6.32
 $4.83
          
Weighted Average Common Shares Outstanding 
  
  
     
Basic179
 177
 175
181
 179
 179
Diluted179
 177
 175
181
 179
 179
Dividends Declared per Common Share$2.84
 $2.69
 $2.59
See Combined Notes to Consolidated Financial Statements


53




DTE Energy Company
Consolidated Statements of Comprehensive Income
Year Ended December 31,Year Ended December 31,
2015 2014 20132018 2017 2016
(In millions)(In millions)
Net Income$720
 $911
 $668
$1,118
 $1,112
 $834
          
Other comprehensive income (loss), net of tax:          
Benefit obligations, net of taxes of $8, $(9), and $13, respectively13
 (18) 22
Benefit obligations, net of taxes of $2, $5, and $6, respectively8
 10
 11
Net unrealized gains (losses) on derivatives during the period, net of taxes of $— for all periods(1) 1
 
Net unrealized gains on investments during the period, net of taxes of $—, $1, and $1, respectively1
 1
 2

 1
 1
Foreign currency translation(4) (2) (2)(2) 1
 
Other comprehensive income (loss)10
 (19) 22
Other comprehensive income5
 13
 12
          
Comprehensive income730
 892
 690
1,123
 1,125
 846
Less comprehensive income (loss) attributable to noncontrolling interests(7) 6
 7
Comprehensive income attributable to DTE Energy Company$737
 $886
 $683
Less: Comprehensive loss attributable to noncontrolling interests(2) (22) (34)
Comprehensive Income Attributable to DTE Energy Company$1,125
 $1,147
 $880
See Combined Notes to Consolidated Financial Statements


54




DTE Energy Company
Consolidated Statements of Financial Position
December 31,December 31,
2015 20142018 2017
(In millions)(In millions)
ASSETS
Current Assets      
Cash and cash equivalents$37
 $48
$71
 $66
Restricted cash23
 120
5
 23
Accounts receivable (less allowance for doubtful accounts of $49 and $54, respectively)   
Accounts receivable (less allowance for doubtful accounts of $91 and $49, respectively)   
Customer1,276
 1,504
1,789
 1,758
Other72
 94
108
 98
Inventories      
Fuel and gas480
 512
406
 399
Materials and supplies323
 292
405
 380
Derivative assets129
 128
102
 103
Regulatory assets32
 76
153
 55
Other203
 238
221
 199
2,575
 3,012
3,260
 3,081
Investments      
Nuclear decommissioning trust funds1,236
 1,241
1,378
 1,492
Investments in equity method investees514
 434
1,771
 1,073
Other186
 194
219
 232
1,936
 1,869
3,368
 2,797
Property      
Property, plant, and equipment28,121
 26,538
31,810
 31,424
Less accumulated depreciation and amortization(10,087) (9,718)
Accumulated depreciation and amortization(10,160) (10,703)
18,034
 16,820
21,650
 20,721
Other Assets     ��
Goodwill2,018
 2,018
2,293
 2,293
Regulatory assets3,692
 3,651
4,568
 3,723
Securitized regulatory assets
 34
Intangible assets89
 102
849
 867
Notes receivable85
 90
64
 73
Derivative assets54
 44
31
 51
Prepaid postretirement costs45
 
Other254
 259
160
 161
6,192
 6,198
8,010
 7,168
Total Assets$28,737
 $27,899
$36,288
 $33,767
See Combined Notes to Consolidated Financial Statements

55




DTE Energy Company
Consolidated Statements of Financial Position — (Continued)
December 31,December 31,
2015 20142018 2017
(In millions, except shares)(In millions, except shares)
LIABILITIES AND EQUITY
Current Liabilities      
Accounts payable$809
 $973
$1,329
 $1,171
Accrued interest89
 86
127
 111
Dividends payable131
 122
172
 158
Short-term borrowings499
 398
609
 621
Current portion long-term debt, including capital leases473
 274
1,499
 109
Derivative liabilities57
 77
67
 99
Regulatory liabilities41
 153
126
 18
Other429
 494
509
 525
2,528
 2,577
4,438
 2,812
Long-Term Debt (net of current portion)      
Mortgage bonds, notes, and other8,340
 7,860
10,982
 11,039
Junior subordinated debentures480
 480
1,145
 1,145
Capital lease obligations15
 3
7
 1
8,835
 8,343
12,134
 12,185
Other Liabilities 
  
   
Deferred income taxes3,923
 3,701
1,975
 1,888
Regulatory liabilities569
 667
2,922
 2,875
Asset retirement obligations2,194
 1,962
2,469
 2,320
Unamortized investment tax credit62
 41
138
 122
Derivative liabilities86
 8
89
 47
Accrued pension liability1,133
 1,280
837
 924
Accrued postretirement liability228
 515

 61
Nuclear decommissioning177
 182
205
 220
Other207
 281
364
 323
8,579
 8,637
8,999
 8,780
   
Commitments and Contingencies (Notes 8 and 17)   
Commitments and Contingencies (Notes 9 and 18)   


 



 

Equity      
Common stock, without par value, 400,000,000 shares authorized, and 179,470,213 and 176,991,231 shares issued and outstanding, respectively4,123
 3,904
Common stock (No par value, 400,000,000 shares authorized, and 181,925,281 and 179,386,967 shares issued and outstanding at December 31, 2018 and December 31, 2017, respectively)4,245
 3,989
Retained earnings4,794
 4,578
6,112
 5,643
Accumulated other comprehensive loss(145) (155)(120) (120)
Total DTE Energy Company Equity8,772
 8,327
10,237
 9,512
Noncontrolling interests23
 15
480
 478
Total Equity8,795
 8,342
10,717
 9,990
Total Liabilities and Equity$28,737
 $27,899
$36,288
 $33,767
See Combined Notes to Consolidated Financial Statements

56




DTE Energy Company
Consolidated Statements of Cash Flows

Year Ended December 31,Year Ended December 31,
2015 2014 20132018 2017 2016
Operating Activities(In millions)(In millions)
Net Income$720
 $911
 $668
$1,118
 $1,112
 $834
Adjustments to reconcile Net Income to net cash from operating activities:     
Adjustments to reconcile Net Income to Net cash from operating activities:     
Depreciation and amortization852
 1,145
 1,094
1,124
 1,030
 976
Nuclear fuel amortization46
 48
 38
45
 53
 58
Allowance for equity funds used during construction(21) (21) (15)(28) (23) (21)
Deferred income taxes237
 356
 164
114
 196
 265
Equity earnings of equity method investees(66) (48) (59)(132) (102) (68)
Dividends from equity method investees64
 55
 61
74
 74
 68
Asset (gains) losses and impairments, net107
 (4) (8)29
 38
 8
Changes in assets and liabilities:          
Accounts receivable, net259
 48
 (154)(44) (252) (226)
Inventories1
 (177) 123
(32) (4) 37
Prepaid postretirement benefit costs(45) 
 
Accounts payable(158) 128
 14
146
 129
 145
Accrued pension liability(147) 627
 (644)(87) (228) 19
Accrued postretirement liability(287) 165
 (526)(61) 25
 (192)
Derivative assets and liabilities47
 (199) 107
31
 (94) 126
Regulatory assets and liabilities85
 (1,177) 1,269
15
 217
 (40)
Other current and noncurrent assets and liabilities172
 (18) 22
413
 (54) 95
Net cash from operating activities1,911
 1,839
 2,154
2,680
 2,117
 2,084
Investing Activities          
Plant and equipment expenditures — utility(1,817) (1,784) (1,534)(2,439) (2,037) (1,898)
Plant and equipment expenditures — non-utility(203) (265) (342)(274) (213) (147)
Acquisition(241) 
 
Proceeds from sale of assets16
 45
 36
Restricted cash for debt redemption, principally Securitization, net97
 3
 (1)
Acquisition, net of cash acquired
 
 (1,147)
Proceeds from sale of nuclear decommissioning trust fund assets885
 1,146
 1,118
1,203
 1,240
 1,457
Investment in nuclear decommissioning trust funds(898) (1,156) (1,134)(1,188) (1,226) (1,463)
Distributions from equity method investees19
 13
 8
9
 10
 11
Contributions to equity method investees(98) (42) (21)(637) (299) (239)
Other36
 (20) (36)(21) (37) 36
Net cash used for investing activities(2,204) (2,060) (1,906)(3,347) (2,562) (3,390)
Financing Activities          
Issuance of long-term debt, net of issuance costs956
 1,736
 1,234
1,432
 1,398
 2,035
Redemption of long-term debt(286) (1,237) (961)(105) (385) (807)
Repurchase of long-term debt
 
 (59)
Issuance of equity units, net of issuance costs
 
 654
Short-term borrowings, net101
 267
 (109)(12) 122
 
Issuance of common stock9
 
 39
Repurchase of common stock
 (52) 

 (51) (33)
Dividends on common stock(501) (470) (445)(620) (592) (531)
Contributions from noncontrolling interests, principally REF entities53
 50
 114
Distributions to noncontrolling interests(48) (40) (5)
Other3
 (27) (19)(46) (81) (9)
Net cash from (used for) financing activities282
 217
 (261)
Net Decrease in Cash and Cash Equivalents(11) (4) (13)
Cash and Cash Equivalents at Beginning of Period48
 52
 65
Cash and Cash Equivalents at End of Period$37
 $48
 $52
Net cash from financing activities654
 421
 1,359
Net Increase (Decrease) in Cash, Cash Equivalents, and Restricted Cash(13) (24) 53
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period89
 113
 60
Cash, Cash Equivalents, and Restricted Cash at End of Period$76
 $89
 $113
          
Supplemental disclosure of cash information          
Cash paid (received) for:          
Interest, net of interest capitalized$428
 $415
 $418
$572
 $495
 $448
Income taxes$14
 $(35) $121
$(26) $4
 $(1)
Supplemental disclosure of non-cash investing and financing activities          
Plant and equipment expenditures in accounts payable$207
 $212
 $329
$307
 $295
 $312
Premium on equity units$
 $
 $98
See Combined Notes to Consolidated Financial Statements

57




DTE Energy Company
Consolidated Statements of Changes in Equity
       Accumulated    
       Other Non-  
 Common Stock Retained Comprehensive Controlling  
 Shares Amount Earnings Income (Loss) Interest Total
 (Dollars in millions, shares in thousands)
Balance, December 31, 2012172,352
 $3,587
 $3,944
 $(158) $38
 $7,411
Net Income
 
 661
 
 7
 668
Dividends declared on common stock
 
 (454) 
 
 (454)
Issuance of common stock589
 39
 
 
 
 39
Contribution of common stock to pension plan3,026
 200
 
 
 
 200
Benefit obligations, net of tax
 
 
 22
 
 22
Net change in unrealized gains on investments, net of tax
 
 
 2
 
 2
Foreign currency translation
 
 
 (2) 
 (2)
Stock-based compensation, distributions to noncontrolling interests, and other1,120
 81
 (1) 
 (12) 68
Balance, December 31, 2013177,087
 $3,907
 $4,150
 $(136) $33
 $7,954
Net Income
 
 905
 
 6
 911
Dividends declared on common stock
 
 (476) 
 
 (476)
Repurchase of common stock(713) (52) 
 
 
 (52)
Benefit obligations, net of tax
 
 
 (18) 
 (18)
Net change in unrealized gains on investments, net of tax
 
 
 1
 
 1
Foreign currency translation      (2)   (2)
Stock-based compensation, distributions to noncontrolling interests, and other617
 49
 (1) 
 (24) 24
Balance, December 31, 2014176,991
 $3,904
 $4,578
 $(155) $15
 $8,342
Net Income (Loss)
 
 727
 
 (7) 720
Dividends declared on common stock
 
 (510) 
 
 (510)
Issuance of common stock105
 9
 
 
 
 9
Contribution of common stock to VEBA Trust1,428
 117
 
 
 
 117
Benefit obligations, net of tax
 
 
 13
 
 13
Net change in unrealized gains on investments, net of tax
 
 
 1
 
 1
Foreign currency translation
 
 
 (4) 
 (4)
Stock-based compensation, net contributions from noncontrolling interests, and other946
 93
 (1) 
 15
 107
Balance, December 31, 2015179,470
 $4,123
 $4,794
 $(145) $23
 $8,795
     Retained Earnings Accumulated Other Comprehensive Income (Loss) Noncontrolling Interests  
 Common Stock     
 Shares Amount    Total
 (Dollars in millions, shares in thousands)
Balance, December 31, 2015179,470
 $4,123
 $4,794
 $(145) $23
 $8,795
Implementation of ASU 2016-09
 
 3
 
 
 $3
Net Income (Loss)
 
 868
 
 (34) 834
Dividends declared on common stock ($3.06 per Common Share)
 
 (548) 
 
 (548)
Repurchase of common stock(394) (33) 
 
 
 (33)
Premium on equity units
 (98) 
 
 
 (98)
Issuance costs of equity units
 (18) 
 
 
 (18)
Acquisition of SGG
 
 
 
 390
 390
Other comprehensive income, net of tax
 
 
 12
 
 12
Stock-based compensation, net contributions from noncontrolling interests, and other357
 56
 (3) 
 109
 162
Balance, December 31, 2016179,433
 $4,030
 $5,114
 $(133) $488
 $9,499
Net Income (Loss)
 
 1,134
 
 (22) 1,112
Dividends declared on common stock ($3.36 per Common Share)
 
 (602) 
 
 (602)
Repurchase of common stock(524) (51) 
 
 
 (51)
Other comprehensive income, net of tax
 
 
 13
 
 13
Stock-based compensation, net contributions from noncontrolling interests, and other478
 10
 (3) 
 12
 19
Balance, December 31, 2017179,387
 $3,989
 $5,643
 $(120) $478
 $9,990
Implementation of ASU 2016-01
 
 5
 (5) 
 
Net Income (Loss)
 
 1,120
 
 (2) 1,118
Dividends declared on common stock ($3.60 per Common Share)
 
 (653) 
 
 (653)
Issuance of common stock255
 26
 
 
 
 26
Contribution of common stock to pension plan1,751
 175
 
 
 
 175
Other comprehensive income, net of tax
 
 
 5
 
 5
Stock-based compensation, net contributions from noncontrolling interests, and other532
 55
 (3) 
 4
 56
Balance, December 31, 2018181,925
 $4,245
 $6,112
 $(120) $480
 $10,717
See Combined Notes to Consolidated Financial Statements


58




DTE Electric — Controls and Procedures
(a) Evaluation of disclosure controls and procedures
Management of DTE Electric carried out an evaluation, under the supervision and with the participation of DTE Electric’s Chief Executive Officer (CEO) and Chief Financial Officer (CFO), of the effectiveness of the design and operation of DTE Electric’s disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) as of December 31, 2015,2018, which is the end of the period covered by this report. Based on this evaluation, DTE Electric’s CEO and CFO have concluded that such disclosure controls and procedures are effective in providing reasonable assurance that information required to be disclosed by DTE Electric in reports that it files or submits under the Exchange Act (i) is recorded, processed, summarized, and reported within the time periods specified in the U.S. Securities and Exchange Commission's rules and forms and (ii) is accumulated and communicated to DTE Electric’s management, including its CEO and CFO, as appropriate to allow timely decisions regarding required disclosure. Due to the inherent limitations in the effectiveness of any disclosure controls and procedures, management cannot provide absolute assurance that the objectives of its disclosure controls and procedures will be attained.
(b) Management’s report on internal control over financial reporting
Management of DTE Electric is responsible for establishing and maintaining adequate internal control over financial reporting as such term is defined in Exchange Act Rules 13a-15(f) and 15d-15(f). Internal control over financial reporting is a process designed by, or under the supervision of, DTE Electric's CEO and CFO, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles.
Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.
Management of DTE Electric has assessed the effectiveness of DTE Electric’s internal control over financial reporting as of December 31, 2015.2018. In making this assessment, management used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (2013 COSO) in Internal Control - Integrated Framework. Based on this assessment, management concluded that, as of December 31, 2015,2018, DTE Electric’s internal control over financial reporting was effective based on those criteria.
This annual report does not include an audit report of DTE Electric’s independent registered public accounting firm regarding internal control over financial reporting. Management’s report was not subject to audit by DTE Electric’s independent registered public accounting firm pursuant to rules of the Securities and Exchange Commission that permit DTE Electric to provide only management’s report in this annual report.
(c) Changes in internal control over financial reporting
There have been no changes in DTE Electric’s internal control over financial reporting during the quarter ended December 31, 20152018 that have materially affected, or are reasonably likely to materially affect, DTE Electric’s internal control over financial reporting.

59




REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM


To the Board of Directors and Shareholder of
DTE Electric Company

Opinion on the Financial Statements
In our opinion, the consolidated financial statements listed inWe have audited the accompanying index present fairly, in all material respects, theconsolidatedstatements of financial positionof DTE Electric Company and itssubsidiaries at(the “Company”) as of December 31, 20152018 and 2014,2017, and the resultsrelated consolidated statements of their operations, of comprehensive income, of changes in shareholder’s equity and theirof cash flows for each of the three years in the period ended December 31, 20152018, including the related notes and schedule of valuation and qualifying accounts for each of the three years in the period ended December 31, 2018 listed in the accompanying index (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2018 and 2017, and the results of its operations and itscash flows for each of the three years in the period ended December 31, 2018 in conformity with accounting principles generally accepted in the United States of America. In addition, in our opinion, the
Basis for Opinion
These consolidated financial statement schedule listed in the accompanying indexpresents fairly, in all material respects, the information set forth therein when read in conjunction with the related consolidatedfinancial statements. These financial statements and financial statement schedule are the responsibility of the Company’sCompany's management. Our responsibility is to express an opinion on thesethe Company’s consolidated financial statements and financial statement schedule based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.
We conducted our audits of these consolidated financial statements in accordance with the standards of the Public Company Accounting Oversight Board (United States).PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement. Anmisstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit includesof its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company's internal control over financial reporting. Accordingly, we express no such opinion.
Our audits included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence supportingregarding the amounts and disclosures in the consolidated financial statements, assessingstatements. Our audits also included evaluating the accounting principles used and significant estimates made by management, andas well as evaluating the overall presentation of the consolidated financial statement presentation.statements. We believe that our audits provide a reasonable basis for our opinion.


/s/ PricewaterhouseCoopers LLP

Detroit, Michigan
February 10, 20167, 2019

60We have served as the Company's auditor since 2008.




DTE Electric Company
Consolidated Statements of Operations
Year Ended December 31,Year Ended December 31,
2015 2014 20132018 2017 2016
(In millions)(In millions)
Operating Revenues — Utility operations$4,900
 $5,282
 $5,197
$5,298
 $5,102
 $5,225
          
Operating Expenses 
  
  
     
Fuel and purchased power — utility1,574
 1,706
 1,668
1,552
 1,454
 1,532
Operation and maintenance1,342
 1,331
 1,376
1,470
 1,428
 1,455
Depreciation and amortization633
 927
 896
836
 753
 750
Taxes other than income277
 267
 260
307
 302
 284
Asset (gains) losses and impairments, net
 (1) (3)(1) 
 
3,826
 4,230
 4,197
4,164
 3,937
 4,021
Operating Income1,074
 1,052
 1,000
1,134
 1,165
 1,204
          
Other (Income) and Deductions 
  
  
     
Interest expense258
 250
 268
283
 274
 264
Interest income
 (1) 

 
 (8)
Other income(60) (62) (54)(83) (77) (61)
Other expenses40
 35
 45
77
 40
 34
238
 222
 259
277
 237
 229
Income Before Income Taxes836
 830
 741
857
 928
 975
          
Income Tax Expense292
 298
 254
193
 327
 353
          
Net Income$544
 $532
 $487
$664
 $601
 $622
See Combined Notes to Consolidated Financial Statements

61




DTE Electric Company
Consolidated Statements of Comprehensive Income
 Year Ended December 31,
 2015 2014 2013
 (In millions)
Net Income$544
 $532
 $487
Other comprehensive income (loss), net of tax: 
  
  
Transfer of benefit obligations, net of taxes of $18 in 201527
 
 
Benefit obligations, net of taxes of $(4) and $4 for 2014 and 2013, respectively
 (10) 5
Net unrealized gains on investments during the period, net of taxes of $—, $—, and $—, respectively1
 
 1
Other comprehensive income (loss)28

(10)
6
Comprehensive income$572

$522

$493
 Year Ended December 31,
 2018 2017 2016
 (In millions)
Net Income$664
 $601
 $622
Other comprehensive income, net of tax:     
Net unrealized gains on investments during the period, net of taxes of $—, $1, and $—, respectively
 1
 
Other comprehensive income

1


Comprehensive Income$664

$602

$622
See Combined Notes to Consolidated Financial Statements

62




DTE Electric Company
Consolidated Statements of Financial Position
December 31,December 31,
2015 20142018 2017
(In millions)(In millions)
ASSETS
Current Assets 
  
   
Cash and cash equivalents$15
 $14
$18
 $15
Restricted cash, principally Securitization
 96
Accounts receivable (less allowance for doubtful accounts of $28 and $29, respectively) 
  
Accounts receivable (less allowance for doubtful accounts of $53 and $31, respectively)   
Customer657
 688
750
 791
Affiliates14
 31
11
 20
Other40
 15
54
 37
Inventories 
  
   
Fuel271
 269
171
 190
Materials and supplies251
 231
279
 275
Notes receivable   
Affiliates
 8
Other
 8
Regulatory assets17
 46
148
 50
Other66
 73
89
 68
1,331
 1,479
1,520
 1,446
Investments      
Nuclear decommissioning trust funds1,236
 1,241
1,378
 1,492
Other35
 172
34
 36
1,271
 1,413
1,412
 1,528
Property      
Property, plant, and equipment21,391
 19,805
22,747
 22,972
Less accumulated depreciation and amortization(7,646) (7,216)
Accumulated depreciation and amortization(7,310) (7,984)
13,745
 12,589
15,437
 14,988
Other Assets 
  
   
Regulatory assets2,969
 2,913
3,829
 3,005
Securitized regulatory assets
 34
Intangible assets34
 37
21
 25
Prepaid postretirement costs — affiliates24
 
189
 113
Other180
 182
121
 123
3,207
 3,166
4,160
 3,266
Total Assets$19,554
 $18,647
$22,529
 $21,228
See Combined Notes to Consolidated Financial Statements

63




DTE Electric Company
Consolidated Statements of Financial Position — (Continued)
December 31,December 31,
2015 20142018 2017
(In millions, except shares)(In millions, except shares)
LIABILITIES AND SHAREHOLDER'S EQUITY
Current Liabilities      
Accounts payable      
Affiliates$40
 $60
$71
 $52
Other329
 366
441
 416
Accrued interest62
 58
74
 72
Current portion long-term debt, including capital leases157
 118
4
 5
Regulatory liabilities19
 150
98
 17
Short-term borrowings      
Affiliates75
 84
101
 116
Other272
 50
149
 238
Other138
 151
139
 145
1,092
 1,037
1,077
 1,061
Long-Term Debt (net of current portion) 
  
   
Mortgage bonds, notes, and other5,473
 5,144
6,538
 6,017
Capital lease obligations15
 
7
 1
5,488
 5,144
6,545
 6,018
Other Liabilities 
  
   
Deferred income taxes3,498
 3,186
2,246
 2,088
Regulatory liabilities199
 245
2,171
 2,137
Asset retirement obligations2,020
 1,796
2,271
 2,125
Unamortized investment tax credit58
 36
137
 120
Nuclear decommissioning177
 182
205
 220
Accrued pension liability — affiliates976
 1,200
718
 811
Accrued postretirement liability — affiliates307
 520
278
 311
Other66
 105
88
 72
7,301
 7,270
8,114
 7,884
   
Commitments and Contingencies (Notes 8 and 17)
 
Commitments and Contingencies (Notes 9 and 18)

 

      
Shareholder's Equity      
Common stock, $10 par value, 400,000,000 shares authorized, and 138,632,324 shares issued and outstanding4,086
 3,786
Common stock ($10 par value, 400,000,000 shares authorized, and 138,632,234 shares issued and outstanding for both periods)4,631
 4,306
Retained earnings1,585
 1,436
2,162
 1,956
Accumulated other comprehensive income (loss)2
 (26)
Accumulated other comprehensive income
 3
Total Shareholder's Equity5,673
 5,196
6,793
 6,265
Total Liabilities and Shareholder's Equity$19,554
 $18,647
$22,529
 $21,228
See Combined Notes to Consolidated Financial Statements

64




DTE Electric Company
Consolidated Statements of Cash Flows
Year Ended December 31,
2015 2014 2013Year Ended December 31,
(In millions)2018 2017 2016
Operating Activities     (In millions)
Net Income$544
 $532
 $487
$664
 $601
 $622
Adjustments to reconcile Net Income to net cash from operating activities: 
  
  
Adjustments to reconcile Net Income to Net cash from operating activities:     
Depreciation and amortization633
 927
 896
836
 753
 750
Nuclear fuel amortization46
 48
 38
45
 53
 58
Allowance for equity funds used during construction(20) (21) (14)(19) (18) (18)
Deferred income taxes320
 297
 108
189
 345
 342
Asset (gains) losses and impairments, net
 (1) (3)
Changes in assets and liabilities:          
Accounts receivable, net33
 33
 (30)33
 (80) (64)
Inventories(22) (97) 36
15
 31
 26
Prepaid postretirement benefit costs — affiliates(24) 
 
(76) 1
 (90)
Accounts payable(46) 11
 (23)54
 (2) 59
Accrued pension liability — affiliates(224) 495
 (663)(93) (197) 32
Accrued postretirement liability — affiliates(213) 151
 (417)(33) 42
 (38)
Regulatory assets and liabilities65
 (926) 1,029
4
 202
 10
Other current and noncurrent assets and liabilities58
 (65) 44
101
 (147) (34)
Net cash from operating activities1,150
 1,384
 1,488
1,720
 1,584
 1,655
Investing Activities          
Plant and equipment expenditures(1,545) (1,561) (1,325)(1,989) (1,574) (1,503)
Acquisitions(310) 
 
Restricted cash for debt redemption, principally Securitization, net96
 4
 2
Notes receivable — affiliate8
 192
 (200)
Proceeds from sale of nuclear decommissioning trust fund assets885
 1,146
 1,118
1,203
 1,240
 1,457
Investment in nuclear decommissioning trust funds(898) (1,156) (1,134)(1,188) (1,226) (1,463)
Transfer of Rabbi Trust assets to affiliate137
 
 
Other6
 (14) (33)(15) 18
 36
Net cash used for investing activities(1,621) (1,389) (1,572)(1,989) (1,542) (1,473)
Financing Activities          
Issuance of long-term debt, net of issuance costs495
 942
 768
519
 435
 355
Redemption of long-term debt(135) (837) (590)
 (300) (10)
Repurchase of long-term debt
 
 (59)
Capital contribution by parent company300
 190
 400
325
 100
 120
Short-term borrowings, net — affiliate(15) (1) 41
Short-term borrowings, net — other222
 50
 (130)(89) 176
 (210)
Short-term borrowings, net — affiliate(8) 26
 (22)
Dividends on common stock(395) (370) (342)(461) (432) (420)
Other(7) (9) (3)(7) (18) (1)
Net cash from (used for) financing activities472
 (8) 81
272
 (40) (184)
Net Increase (Decrease) in Cash and Cash Equivalents1
 (13) (3)3
 2
 (2)
Cash and Cash Equivalents at Beginning of Period14
 27
 30
15
 13
 15
Cash and Cash Equivalents at End of Period$15
 $14
 $27
$18
 $15
 $13
          
Supplemental disclosure of cash information          
Cash paid (received) for:          
Interest, net of interest capitalized$244
 $240
 $256
$283
 $252
 $252
Income taxes$(53) $4
 $183
$
 $(16) $6
Supplemental disclosure of non-cash investing and financing activities          
Plant and equipment expenditures in accounts payable$150
 $162
 $231
$181
 $191
 $232
See Combined Notes to Consolidated Financial Statements

65




DTE Electric Company
Consolidated Statements of Changes in Shareholder's Equity
        Accumulated      Additional Paid-in Capital Retained Earnings Accumulated Other Comprehensive Income (Loss)  
    Additional   Other  Common Stock  
Common Stock Paid in Retained Comprehensive  Shares Amount Total
Shares Amount Capital Earnings Income (Loss) Total(Dollars in millions, shares in thousands)
(Dollars in millions, shares in thousands)
Balance, December 31, 2012138,632
 $1,386
 $1,810
 $1,129
 $(22) $4,303
Balance, December 31, 2015138,632
 $1,386
 $2,700
 $1,585
 $2
 $5,673
Net Income
 
 
 487
 
 487

 
 
 622
 
 622
Dividends declared on common stock
 
 
 (342) 
 (342)
 
 
 (420) 
 (420)
Benefit obligations, net of tax
 
 
 
 5
 5
Net change in unrealized gains on investments, net of tax
 
 
 
 1
 1
Capital contribution by parent company
 
 400
 
 
 400

 
 120
 
 
 120
Balance, December 31, 2013138,632
 $1,386
 $2,210
 $1,274
 $(16) $4,854
Balance, December 31, 2016138,632
 $1,386
 $2,820
 $1,787
 $2
 $5,995
Net Income
 
 
 532
 
 532

 
 
 601
 
 601
Dividends declared on common stock
 
 
 (370) 
 (370)
 
 
 (432) 
 (432)
Benefit obligations, net of tax
 
 
 
 (10) (10)
Other comprehensive income, net of tax
 
 
 
 1
 1
Capital contribution by parent company
 
 190
 
 
 190

 
 100
 
 
 100
Balance, December 31, 2014138,632
 $1,386
 $2,400
 $1,436
 $(26) $5,196
Balance, December 31, 2017138,632
 $1,386
 $2,920
 $1,956
 $3
 $6,265
Implementation of ASU 2016-01
 
 
 3
 (3) 
Net Income
 
 
 544
 
 544

 
 
 664
 
 664
Dividends declared on common stock
 
 
 (395) 
 (395)
 
 
 (461) 
 (461)
Transfer of benefit obligations, net of tax
 
 
 
 27
 27
Net change in unrealized gains on investments, net of tax
 
 
 
 1
 1
Capital contribution by parent company
 
 300
 
 
 300

 
 325
 
 
 325
Balance, December 31, 2015138,632
 $1,386
 $2,700
 $1,585
 $2
 $5,673
Balance, December 31, 2018138,632
 $1,386
 $3,245
 $2,162
 $
 $6,793
See Combined Notes to Consolidated Financial Statements

66


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements


Index of Combined Notes to Consolidated Financial Statements
The Combined Notes to Consolidated Financial Statements are a combined presentation for DTE Energy and DTE Electric. The following list indicates the Registrant(s) to which each note applies:
Note 1 Organization and Basis of Presentation DTE Energy and DTE Electric
Note 2 Significant Accounting Policies DTE Energy and DTE Electric
Note 3 New Accounting Pronouncements DTE Energy and DTE Electric
Note 4 Acquisitions and Exit ActivitiesRevenue DTE Energy and DTE Electric
Note 5GoodwillDTE Energy
Note 6 Property, Plant, and Equipment DTE Energy and DTE Electric
Note 67 Jointly-Owned Utility Plant DTE Energy and DTE Electric
Note 78 Asset Retirement Obligations DTE Energy and DTE Electric
Note 89 Regulatory Matters DTE Energy and DTE Electric
Note 910 Income Taxes DTE Energy and DTE Electric
Note 1011 Earnings Per Share DTE Energy
Note 1112 Fair Value DTE Energy and DTE Electric
Note 1213 Financial and Other Derivative Instruments DTE Energy and DTE Electric
Note 1314 Long-Term Debt DTE Energy and DTE Electric
Note 1415 Preferred and Preference Securities DTE Energy and DTE Electric
Note 1516 Short-Term Credit Arrangements and Borrowings DTE Energy and DTE Electric
Note 1617 Capital and Operating Leases DTE Energy and DTE Electric
Note 1718 Commitments and Contingencies DTE Energy and DTE Electric
Note 1819Nuclear OperationsDTE Energy and DTE Electric
Note 20 Retirement Benefits and Trusteed Assets DTE Energy and DTE Electric
Note 1921 Stock-Based Compensation DTE Energy and DTE Electric
Note 2022 Segment and Related Information DTE Energy
Note 2123 Related Party Transactions DTE Electric
Note 2224 Supplementary Quarterly Financial Information (Unaudited) DTE Energy and DTE Electric

NOTE 1 — ORGANIZATION AND BASIS OF PRESENTATION
Corporate Structure
DTE Energy owns the following businesses:
DTE Electric is a public utility engaged in the generation, purchase, distribution, and sale of electricity to approximately 2.2 million customers in southeastern Michigan;
DTE Gas is a public gas utility engaged in the purchase, storage, transportation, distribution, and sale of natural gas to approximately 1.21.3 million customers throughout Michigan and the sale of storage and transportation capacity; and
Other businesses involved in 1) services related to the gathering, transportation, and storage of natural gas pipelines, gathering, and storage;gas; 2) power and industrial projects; and 3) energy marketing and trading operations.
DTE Electric and DTE Gas are regulated by the MPSC. Certain activities of DTE Electric and DTE Gas, as well as various other aspects of businesses under DTE Energy are regulated by the FERC. In addition, the Registrants are regulated by other federal and state regulatory agencies including the NRC, the EPA, the MDEQ, and for DTE Energy, the CFTC.

67


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Basis of Presentation
The accompanying Consolidated Financial Statements of the Registrants are prepared using accounting principles generally accepted in the United States of America. These accounting principles require management to use estimates and assumptions that impact reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Actual results may differ from the Registrants' estimates.
The information in these combined notes relates to each of the Registrants as noted in the Index of Combined Notes to Consolidated Financial Statements. However, DTE Electric does not make any representation as to information related solely to DTE Energy or the subsidiaries of DTE Energy other than itself.
Certain prior year balances for the Registrants were reclassified to match the current year's Consolidated Financial Statements presentation. Such revisions include
Due to the implementation of ASU 2017-07, amounts previously included in Operation and maintenance were reclassified to separate Operating Revenues and Fuel, purchased power, and gas between Utility operations and Non-utility operations and from Operations and maintenance to Fuel, purchased power, and gas — non-utility related toNon-operating retirement benefits, net on the Power and Industrial Projects segment. The reclassifications did not affect DTE Energy's Net Income for the prior periods, as such, they are not deemed material to the previously issued Consolidated Financial Statements. For reclassificationsStatements of deferred tax assets and liabilities arising from ASU 2015-17 seeOperations. See Note 3 to the Consolidated Financial Statements, "New Accounting Pronouncements".Pronouncements."
Principles of Consolidation
The Registrants consolidate all majority-owned subsidiaries and investments in entities in which they have controlling influence. Non-majority owned investments are accounted for using the equity method when the Registrants are able to significantly influence the operating policies of the investee. When the Registrants do not influence the operating policies of an investee, the cost method is used. These Consolidated Financial Statements also reflect the Registrants' proportionate interests in certain jointly-owned utility plants. The Registrants eliminate all intercompany balances and transactions.
The Registrants evaluate whether an entity is a VIE whenever reconsideration events occur. The Registrants consolidate VIEs for which they are the primary beneficiary. If a Registrant is not the primary beneficiary and an ownership interest is held, the VIE is accounted for under the equity method of accounting. When assessing the determination of the primary beneficiary, a Registrant considers all relevant facts and circumstances, including: the power, through voting or similar rights, to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb the expected losses and/or the right to receive the expected returns of the VIE. The Registrants perform ongoing reassessments of all VIEs to determine if the primary beneficiary status has changed.
Legal entities within DTE Energy's Power and Industrial Projects segment enter into long-term contractual arrangements with customers to supply energy-related products or services. The entities are generally designed to pass-through the commodity risk associated with these contracts to the customers, with DTE Energy retaining operational and customer default risk. These entities generally are VIEs and consolidated when DTE Energy is the primary beneficiary. In addition, DTE Energy has interests in certain VIEs through which control of all significant activities is shared with partners, and therefore are generally accounted for under the equity method.
DTE Energy owns a 55% interest in SGG, which owns and operates midstream natural gas assets. SGG has contracts through which certain construction risk is designed to pass-through to the customers, with DTE Energy retaining operational and customer default risk. SGG is a VIE with DTE Energy as the primary beneficiary.
The Registrants have variable interests in NEXUS, which include DTE Energy's 50% ownership interest and DTE Electric's transportation services contract. NEXUS is a joint venture which owns a 256-mile pipeline to transport Utica and Marcellus shale gas to Ohio, Michigan, and Ontario market centers. NEXUS is a VIE as it has insufficient equity at risk to finance its activities. The Registrants are not the primary beneficiaries, as the power to direct significant activities is shared between the owners of the equity interests. DTE Energy accounts for its ownership interest in NEXUS under the equity method.
The Registrants hold ownership interests in certain limited partnerships. The limited partnerships include investment funds which support regional development and economic growth, as well as, an operational business providing energy-related products. These entities are generally VIEs as a result of certain characteristics of the limited partnership voting rights. The ownership interests are accounted for under the equity method as the Registrants are not the primary beneficiaries.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

DTE Energy has variable interests in VIEs through certain of its long-term purchase and sale contracts. DTE Electric has variable interests in VIEs through certain of its long-term purchase contracts. As of December 31, 2015,2018, the carrying amount of assets and liabilities in DTE Energy's Consolidated Statements of Financial Position that relate to its variable interests under long-term purchase and sale contracts are predominantly related to working capital accounts and generally represent the amounts owed by or to DTE Energy for the deliveries associated with the current billing cycle under the contracts. As of December 31, 2015,2018, the carrying amount of assets and liabilities in DTE Electric's Consolidated Statements of Financial Position that relate to its variable interests under long-term purchase contracts are predominantly related to working capital accounts and generally represent the amounts owed by DTE Electric for the deliveries associated with the current billing cycle under the contracts. The Registrants have not provided any significant form of financial support associated with these long-term contracts. There is no significant potential exposure to loss as a result of DTE Energy's variable interests through these long-term purchase and sale contracts. In addition, there is no significant potential exposure to loss as a result of DTE Electric's variable interests through these long-term purchase contracts.

68


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

In 2001, DTE Electric financed a regulatory asset related to Fermi 2 and certain other regulatory assets through the sale of rate reduction bonds by a wholly-owned special purpose entity, Securitization. DTE Electric performed servicing activities including billing and collecting surcharge revenue for Securitization. The remaining amounts due on the rate reduction bonds were paid in March 2015. The associated regulatory assets were fully amortized by March 31, 2015. Subsequent to the pay-down of the bonds, Securitization is no longer a VIE but continues to be consolidated by the Registrants as a voting interest entity.
The maximum risk exposure for consolidated VIEs is reflected on the Registrants' Consolidated Statements of Financial Position.Position and for DTE Energy, in Note 18 to the Consolidated Financial Statements, "Commitments and Contingencies," related to the REF guarantees and indemnities. For non-consolidated VIEs, the maximum risk exposure of the Registrants is generally limited to itstheir investment, notes receivable, future funding commitments, and amounts which itDTE Energy has guaranteed. See Note 18 to the Consolidated Financial Statements, "Commitments and Contingencies," for further discussion of the NEXUS guarantee arrangements.
The following table summarizes the major Consolidated Statements of Financial Position items for consolidated VIEs as of December 31, 20152018 and 2014.2017. All assets and liabilities of a consolidated VIE are presented where it has been determined that a consolidated VIE has either (1) assets that can be used only to settle obligations of the VIE or (2) liabilities for which creditors do not have recourse to the general credit of the primary beneficiary. Securitization, included in the DTE Energy table below for December 31, 2014, also relates to DTE Electric. VIEs, in which DTE Energy holds a majority voting interest and is the primary beneficiary, that meet the definition of a business and whose assets can be used for purposes other than the settlement of the VIE's obligations have been excluded from the table below.
Amounts for DTE Energy's consolidated VIEs are as follows:
December 31, 2015 December 31, 2014December 31, 2018 December 31, 2017
Total Securitization Other Total
SGG(a)
 Other Total 
SGG(a)
 Other Total
(In millions)(In millions)
ASSETS                  
Cash and cash equivalents$14
 $
 $7
 $7
$25
 $14
 $39
 $23
 $14
 $37
Restricted cash8
 96
 8
 104

 5
 5
 
 8
 8
Accounts receivable18
 26
 15
 41
9
 37
 46
 11
 42
 53
Inventories82
 
 67
 67
1
 92
 93
 3
 114
 117
Property, plant, and equipment, net66
 
 81
 81
395
 46
 441
 400
 75
 475
Securitized regulatory assets
 34
 
 34
Goodwill25
 
 25
 25
 
 25
Intangible assets557
 
 557
 572
 
 572
Other current and long-term assets4
 1
 6
 7
3
 
 3
 4
 
 4
$192
 $157
 $184
 $341
$1,015
 $194
 $1,209
 $1,038
 $253
 $1,291
                  
LIABILITIES                  
Accounts payable and accrued current liabilities$13
 $3
 $8
 $11
$3
 $31
 $34
 $26
 $47
 $73
Current portion long-term debt, including capital leases8
 105
 10
 115

 
 
 
 4
 4
Current regulatory liabilities
 32
 
 32
Mortgage bonds, notes, and other10
 
 15
 15

 
 
 
 1
 1
Capital lease obligations
 
 3
 3
Other current and long-term liabilities6
 9
 6
 15
9
 10
 19
 1
 16
 17
$37
 $149
 $42
 $191
$12
 $41
 $53
 $27
 $68
 $95

(a)Amounts shown are 100% of SGG's assets and liabilities, of which DTE Energy owns 55%.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Amounts for DTE Energy's non-consolidated VIEs as of December 31, 2015 and 2014 are as follows:
December 31, 2015 December 31, 2014December 31,
(In millions)2018 2017
Investment in equity method investees$136
 $134
(In millions)
Investments in equity method investees$1,425
 $811
Notes receivable$15
 $15
$15
 $17
Future funding commitments$55
 $598
Equity Method Investments
Investments in non-consolidated affiliates that are not controlled by the Registrants, but over which they have significant influence, are accounted for using the equity method. Certain of the equity method investees are also considered VIEs and disclosed in the non-consolidated VIEs table above. At December 31, 20152018 and 2014,2017, DTE Energy's share of the underlying equity in the net assets of the investees exceeded the carrying amounts of Investments in equity method investees by $81$59 million and $72 million, respectively. The difference is being amortized over the life of the underlying assets.

69


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Equityequity method investees are described below:
 Investments % Owned  Investments % Owned 
Segment 2015 2014 2015 2014 Description 2018 2017 2018 2017 Description
 (In millions)  (In millions) 
Significant Equity Method Investees          
Gas Storage and Pipelines          
NEXUS Pipeline $89
 $16
 50% 50% A proposed 255-mile pipeline to transport Utica and Marcellus shale gas to Ohio, Michigan, and Ontario market centers $1,260
 $640
 50% 50% 256-mile pipeline to transport Utica and Marcellus shale gas to Ohio, Michigan, and Ontario market centers
Vector Pipeline 96
 98
 40% 40% 348-mile pipeline connecting Chicago, Michigan, and Ontario market centers 123
 115
 40% 40% 348-mile pipeline connecting Chicago, Michigan, and Ontario market centers
Millennium Pipeline 111
 110
 26% 26% 182-mile pipeline serving markets in the Northeast 202
 124
 26% 26% 269-mile pipeline serving markets in the Northeast
 $296
 $224
  1,585
 879
 
Other Equity Method Investees          
Other Segments 218
 210
  186
 194
 
 $514
 $434
  $1,771
 $1,073
 
The balancebalances in Other Equity Method Investees are individually insignificant and are primarily from the Power and Industrial Projects segment. These investments are comprised of projects that deliver energy and utility-type products and services to an industrial customer, sell electricity from renewable energy projects under long-term power purchase agreements, and produce and sell metallurgical coke.
For further information by segment, see Note 2022 to the Consolidated Financial Statements, "Segment and Related Information".

NOTE 2 — SIGNIFICANT ACCOUNTING POLICIES
RevenuesInformation."
The Registrants' revenues from the salefollowing table presents summarized financial information of subsidiaries not consolidated and delivery of electricity, and50 percent or less owned by DTE Energy's revenues from the sale, delivery, and storage of natural gas are recognized as services are provided. DTE Electric and DTE Gas record revenues for electricity and gas provided but unbilled at the end of each month. Rates for DTE Electric and DTE Gas include provisions to adjust billings for fluctuations in fuel and purchased power costs, cost of natural gas, and certain other costs. Revenues are adjusted for differences between actual costs subject to reconciliation and theEnergy. The amounts billed in current rates. Under or over recovered revenues related to these cost recovery mechanisms are included in Regulatory assets or liabilities on the Registrants' Consolidated Statementstable below represents 100% of Financial Position and are recovered or returned to customers through adjustments to the billing factors.results of continuing operations of such entities accounted for under the equity method of accounting.
For further discussion of recovery mechanisms authorized by the MPSC, see Note 8 to the Consolidated Financial Statements, "Regulatory Matters".Summarized balance sheet data is as follows:
DTE Energy's non-utility businesses recognize revenues as services are provided and products are delivered. For discussion of derivative contracts, see Note 12 to the Consolidated Financial Statements, "Financial and Other Derivative Instruments".

70

 December 31,
 2018 2017
 (In millions)
Current Assets$358
 $344
Non-current assets$5,101
 $3,576
Current Liabilities$391
 $345
Non-current liabilities$762
 $858

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Summarized income statement data is as follows:
 December 31,
 2018 2017 2016
 (In millions)
Operating Revenues$883
 $756
 $767
Operating Expenses$622
 $561
 $526
Net Income$365
 $254
 $225

NOTE 2 — SIGNIFICANT ACCOUNTING POLICIES
Other Income
Other income for the Registrants is recognized for non-operating income such as equity earnings of equity method investees, allowance for equity funds used during construction, contract services, and contract services.gains (losses) from trading securities. DTE Energy's Power and Industrial Projects segment also recognizes Other income in connection with the sale of membership interests in reduced emissions fuel facilities to investors. In exchange for the cash received, the investors will receive a portion of the economic attributes of the facilities, including income tax attributes. The transactions are not treated as a sale of membership interests for financial reporting purposes. Other income related to fixed non-refundable cash payments received from investors for which the earnings process is not contingent upon production of refined coal is recognized on a straight-line basis over the non-cancelable contract term as the economic benefit from the ownership of the facility is transferred to investors. Other income related to cash payments that is contingent upon production of refined coal is considered earned and recognized when the contingency regarding the timing and amount of payment is resolved, generally as refined coal is produced and tax credits are generated. Power and Industrial Projects recognized approximately $83 million, $78 million, and $81 million
The following is a summary of DTE Energy's Other income for the years ended December 31, 2015, 2014, and 2013, respectively.income:
 2018 2017 2016
 (In millions)
Equity earnings of equity method investees$132
 $102
 $68
Income from REF entities98
 77
 75
Contract services51
 19
 21
Allowance for equity funds used during construction28
 23
 21
Gains from trading securities6
 26
 15
Other18
 21
 7
 $333
 $268
 $207
The following is a summary of DTE Electric's Other income:
 2018 2017 2016
 (In millions)
Contract services$51
 $21
 $20
Allowance for equity funds used during construction19
 18
 18
Gains from trading securities allocated from DTE Energy6
 26
 15
Other7
 12
 8
 $83
 $77
 $61
For information on equity earnings of equity method investees by segment, see Note 2022 to the Consolidated Financial Statements, "Segment and Related Information".Information."

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Accounting for ISO Transactions
DTE Electric participates in the energy market through MISO. MISO requires that DTE Electric submit hourly day-ahead, real-time, and FTR bids and offers for energy at locations across the MISO region. DTE Electric accounts for MISO transactions on a net hourly basis in each of the day-ahead, real-time, and FTR markets and net transactions across all MISO energy market locations. In any single hour DTE Electric records net purchases in Fuel, purchased power, and gas utility and net sales in Operating Revenues Utility operations on the Registrants' Consolidated Statements of Operations.
The Energy Trading segment participates in the energy markets through various independent system operatorsISOs and regional transmission organizations (ISOs and RTOs).RTOs. These markets require that Energy Trading submits hourly day-ahead, real-time bids and offers for energy at locations across each region. Energy Trading submits bids in the annual and monthly auction revenue rights and FTR auctions to the regional transmission organizations.RTOs. Energy Trading accounts for these transactions on a net hourly basis for the day-ahead, real-time, and FTR markets. These transactions are related to trading contracts which, if derivatives, are presented on a net basis in Operating Revenues Non-utility operations, and if non-derivatives, the realized gains and losses for sales are recorded in Operating Revenues Non-utility operations and purchases are recorded in Fuel, purchased power, and gas non-utility in the DTE Energy Consolidated Statements of Operations.
DTE Electric and Energy Trading record accruals for future net purchases adjustments based on historical experience, and reconcile accruals to actual costs when invoices are received from MISO and other ISOs and RTOs.
Changes in Accumulated Other Comprehensive Income (Loss)
Comprehensive income (loss) is the change in common shareholders’ equity during a period from transactions and events from non-owner sources, including Net Income. The amounts recorded to Accumulated other comprehensive income (loss) for the Registrants include unrealized gains and losses on available-for-sale securities and changes in benefit obligations, consisting of deferred actuarial losses and prior service costs. The amounts recorded to Accumulated other comprehensive income (loss) relating solely to DTE Energy also include unrealized gains and losses from derivatives accounted for as cash flow hedges, DTE Energy's interest in other comprehensive income of equity investees which comprise the net unrealized gains and losses on investments, and foreign currency translation adjustments. Refer to Note 18 to the Consolidated Financial Statements, "Retirement Benefits and Trusteed Assets", regarding the transfer of a portion of DTE Electric benefit obligations during the year.

71


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following table summarizes the changes in DTE Energy's Accumulated other comprehensive income (loss) by component(a) for the years ended December 31, 20152018 and 2014:2017:
Changes in Accumulated Other Comprehensive Income (Loss) by Component (a)Net Unrealized Gain (Loss) on Derivatives Net Unrealized Gain (Loss) on Investments 
Benefit Obligations(b)
 Foreign Currency Translation Total
Net
Unrealized
Loss
on
Derivatives
 Net
Unrealized
Gain/(Loss)
on
Investments
 Benefit
Obligations
(b)
 Foreign
Currency
Translation
 Total(In millions)
(In millions)
Balance, December 31, 2013$(4) $(6) $(126) $
 $(136)
Balance, December 31, 2016$(4) $(3) $(120) $(6) $(133)
Other comprehensive income (loss) before reclassifications
 1
 (25) (2) (26)
 1
 (3) 1
 (1)
Amounts reclassified from Accumulated other comprehensive income
 
 7
 
 7
1
 
 13
 
 14
Net current-period Other comprehensive income (loss)
 1

(18)
(2)
(19)
Balance, December 31, 2014$(4) $(5)
$(144)
$(2)
$(155)
Other comprehensive income (loss) before reclassifications
 1
 2
 (4) (1)
Net current-period Other comprehensive income1
 1

10

1

13
Balance, December 31, 2017$(3) $(2)
$(110)
$(5)
$(120)
Implementation of ASU 2016-01(7) 2
 
 
 (5)
Other comprehensive loss before reclassifications(2) 
 (1) (2) (5)
Amounts reclassified from Accumulated other comprehensive income
 
 11
 
 11
1
 
 9
 
 10
Net current-period Other comprehensive income (loss)
 1

13

(4)
10
(8) 2

8

(2)

Balance, December 31, 2015$(4) $(4)
$(131)
$(6)
$(145)
Balance, December 31, 2018$(11) $

$(102)
$(7)
$(120)

(a)All amounts are net of tax, except for Foreign currency translation.
(a)All amounts are net of tax, except for Foreign currency translation.
(b)The amounts reclassified from Accumulated other comprehensive income (loss) are included in the computation of the net periodic pension and other postretirement benefit costs (see Note 1820 to the Consolidated Financial Statements, "Retirement Benefits and Trusteed Assets").
The following table summarizes the changes in

DTE Electric's Accumulated other comprehensive income (loss) by component for the years ended December 31, 2015 and 2014:Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)
 Changes in Accumulated Other Comprehensive Income (Loss) by Component (a)
 Net Unrealized Gain on Investments Benefit Obligations (b) Total
 (In millions)
Balance, December 31, 2013$1
 $(17) $(16)
Other comprehensive loss before reclassifications
 (12) (12)
Amounts reclassified from Accumulated other comprehensive income
 2
 2
Net current-period Other comprehensive loss
 (10) (10)
Balance, December 31, 2014$1
 $(27) $(26)
Other comprehensive income before reclassifications1
 
 1
Transfer of amounts from Accumulated other comprehensive income to affiliate
 27
 27
Amounts reclassified from Accumulated other comprehensive income
 
 
Net current-period Other comprehensive income1
 27
 28
Balance, December 31, 2015$2
 $
 $2

(a)All amounts are net of tax.
(b)The amounts reclassified from Accumulated other comprehensive income (loss) are included in the computation of the net periodic pension and other postretirement benefit costs (see Note 18 to the Consolidated Financial Statements "Retirement Benefits and Trusteed Assets").
Cash, Cash Equivalents, and Restricted Cash
Cash and cash equivalents include cash on hand, cash in banks, and temporary investments purchased with remaining maturities of three months or less. Restricted cash consists of funds held to satisfy requirements of certain debt and DTE Energy partnership operating agreements. Restricted cash designated for interest and principal payments within one year is classified as a Current Asset.

The following is a table that provides a reconciliation of DTE Energy's Cash and cash equivalents as well as Restricted cash reported within the Consolidated Statements of Financial Position that sum to the total of the same such amounts shown in the Consolidated Statements of Cash Flows:
72


 2018 2017
 (In millions)
Cash and cash equivalents$71
 $66
Restricted cash5
 23
Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows$76
 $89
DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Receivables
Accounts receivable are primarily composed of trade receivables and unbilled revenue. The Registrants' Accounts receivable are stated at net realizable value.
The allowance for doubtful accounts for DTE Electric and DTE Gas is generally calculated using the aging approach that utilizes rates developed in reserve studies. DTE Electric and DTE Gas establish an allowance for uncollectible accounts based on historical losses and management’s assessment of existing economic conditions, customer trends, and other factors. Customer accounts are generally considered delinquent if the amount billed is not received by the due date, which is typically in 21 days, however, factors such as assistance programs may delay aggressive action. DTE Electric and DTE Gas assess late payment fees on trade receivables based on past-due terms with customers. Customer accounts are written off when collection efforts have been exhausted. The time period for write-off is 150 days after service has been terminated.
The customer allowance for doubtful accounts for DTE Energy's other businesses is calculated based on specific review of probable future collections based on receivable balances generally in excess of 30 days.
DTE Energy unbilled revenues of $620$1.0 billion at December 31, 2018 and 2017 include $264 million and $773 million, including $237 million and $250$290 million of DTE Electric unbilled revenues, arerespectively, included in Customer Accounts receivable at December 31, 2015 and 2014, respectively.receivable.
Notes Receivable
Notes receivable, or financing receivables, for DTE Energy are primarily comprised of capital lease receivables and loans and are included in Notes receivable and Other current assets on DTE Energy’s Consolidated Statements of Financial Position. Notes receivable, or financing receivables, for DTE Electric are primarily comprised of loans.
Notes receivable are typically considered delinquent when payment is not received for periods ranging from 60 to 120 days. The Registrants cease accruing interest (nonaccrual status), consider a note receivable impaired, and establish an allowance for credit loss when it is probable that all principal and interest amounts due will not be collected in accordance with the contractual terms of the note receivable. Cash payments received on nonaccrual status notes receivable, that do not bring the account contractually current, are first applied to contractually owed past due interest, with any remainder applied to principal. Accrual of interest is generally resumed when the note receivable becomes contractually current.
In determining the allowance for credit losses for notes receivable, the Registrants consider the historical payment experience and other factors that are expected to have a specific impact on the counterparty’s ability to pay. In addition, the Registrants monitor the credit ratings of the counterparties from which they have Notesnotes receivable.
Inventories
Inventory related to utility operations is generally valued at average cost. Inventory related to non-utility operations is valued at the lower of cost or market.net realizable value.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

DTE Gas' natural gas inventory of $65$48 million and $43$29 million as of December 31, 20152018 and 2014,2017, respectively, is determined using the last-in, first-out (LIFO) method. The replacement cost of gas remaining in storageinventory exceeded the LIFO cost by $60$113 million and $110$81 million at December 31, 20152018 and 2014,2017, respectively.
Property, Retirement and Maintenance, and Depreciation and Amortization
Property is stated at cost and includes construction-related labor, materials, overheads, and AFUDC for utility property. The cost of utility properties retired is charged to accumulated depreciation. Expenditures for maintenance and repairs are charged to expense when incurred, except for outage-related maintenance repairs for Fermi 2.
Utility property at DTE Electric and DTE Gas is depreciated over its estimated useful life using straight-line rates approved by the MPSC.
DTE Energy's non-utility property is depreciated over its estimated useful life using the straight-line method.
Depreciation and amortization expense also includes the amortization of certain regulatory assets for the Registrants.

73


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Approximately $4 million and $16$15 million of expenses related to Fermi 2 refueling outages were accrued at December 31, 20152018 and 2014,2017, respectively. Amounts are accrued on a pro-rata basis, generally over an 18-month period, that coincides with scheduled refueling outages at Fermi 2. This accrual of outage costs matches the regulatory recovery of these costs in rates set by the MPSC. See Note 89 to the Consolidated Financial Statements, "Regulatory Matters".Matters."
The cost of nuclear fuel is capitalized. The amortization of nuclear fuel is included within Fuel, purchased power, and gas utility in the DTE Energy Consolidated Statements of Operations, and Fuel and purchased power in the DTE Electric Consolidated Statements of Operations, and is recorded using the units-of-production method.
See Note 6 to the Consolidated Financial Statements, "Property, Plant, and Equipment."
Long-Lived Assets
Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If the carrying amount of the asset exceeds the expected discountedundiscounted future cash flows generated by the asset, an impairment loss is recognized resulting in the asset being written down to its estimated fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value, less costs to sell.
Intangible Assets
DTE Energy has certain Intangible assets as shown below:
 December 31,
 2015 2014
 (In millions)
Emission allowances$1
 $1
Renewable energy credits38
 45
Contract intangible assets117
 122
 156
 168
Less accumulated amortization62
 57
Intangible assets, net94
 111
Less current intangible assets5
 9
 $89
 $102
DTE Electric has certain Intangible assets as shown below:
 December 31,
 2015 2014
 (In millions)
Emission allowances$1
 $1
Renewable energy credits38
 45
 39
 46
Less current intangible assets5
 9
 $34
 $37
Emission allowances and renewable energy credits are charged to expense, using average cost, as the allowances and credits are consumed in the operation of the businesses by the Registrants. DTE Energy amortizes contract Intangible assets on a straight-line basis over the expected period of benefit, ranging from 1 to 26 years. DTE Energy's Intangible assets amortization expense was $11 million in 2015, $12 million in 2014, and $14 million in 2013.

74


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Intangible Assets
The Registrants have certain Intangible assets as shown below:
   December 31, 2018 December 31, 2017
 Useful Lives Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value
   (In millions)
Intangible assets subject to amortization            
Customer relationships
25 - 40 years(a)
 $779
 $(44) $735
 $770
 $(24) $746
Contract intangibles6 to 26 years 159
 (66) 93
 168
 (72) 96
   938
 (110) 828
 938
 (96) 842
              
DTE Electric renewable energy credits(b) 20
 
 20
 24
 
 24
DTE Electric emission allowances(b) 1
 
 1
 1
 
 1
   21
 
 21
 25
 
 25
Long-term intangible assets             
DTE Electric  $21
 $
 $21
 $25
 $
 $25
DTE Energy  $959
 $(110) $849
 $963
 $(96) $867

(a)The useful life of the customer relationship intangible assets is based on the number of years in which the assets are expected to economically contribute to the business. The expected economic benefit incorporates existing customer contracts and expected renewal rates based on the estimated volume and production lives of gas resources in the region.
(b)Emission allowances and renewable energy credits are charged to expense, using average cost, as the allowances and credits are consumed in the operation of the business.
The following table summarizes DTE Energy's estimated customer relationship and contract intangible amortization expense expected to be recognized during each year through 2020:2023:
Estimated amortization expense(In millions)
2016$10
2017$7
2018$7
2019$7
2020$5
 2019 2020 2021 2022 2023
 (In millions)
Estimated amortization expense$27
 $26
 $25
 $25
 $25
DTE Energy amortizes customer relationship and contract intangible assets on a straight-line basis over the expected period of benefit. DTE Energy's Intangible assets amortization expense was $27 million in 2018, $29 million in 2017, and $16 million in 2016.
Excise and Sales Taxes
The Registrants record the billing of excise and sales taxes as a receivable with an offsetting payable to the applicable taxing authority, with no net impact on the Registrants'Registrants’ Consolidated Statements of Operations.
Deferred Debt Costs
The costs related to the issuance of long-term debt are deferred and amortized over the life of each debt issue. The deferred amounts are included as a direct deduction from the carrying amount of each debt issue in Other long-term assetsMortgage bonds, notes, and other and Junior subordinated debentures on the Registrant'sDTE Energy's Consolidated Statements of Financial Position and in Mortgage bonds, notes, and other on DTE Electric's Consolidated Statements of Financial Position. In accordance with MPSC regulations applicable to DTE Energy’s electric and gas utilities, the unamortized discount, premium, and expense related to utility debt redeemed with a refinancing are amortized over the life of the replacement issue. Discount, premium, and expense on early redemptions of debt associated with DTE Energy's non-utility operations are charged to earnings.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Investments in Debt and Equity Securities
The Registrants generally classifyrecord investments in debt and equity securities as either trading or available-for-sale and have recorded such investments at market value with unrealized gains or losses included in earnings or in Other comprehensive income or loss, respectively.earnings. Changes in the fair value of Fermi 2 nuclear decommissioning investments are recorded as adjustments to Regulatory assets or liabilities, due to a recovery mechanism from customers. The Registrants' equity investments are reviewed for impairment each reporting period. If the assessment indicates that thean impairment is other than temporary,exists, a loss is recognized resulting in the equity investment being written down to its estimated fair value. See Note 1112 of the Consolidated Financial Statements, "Fair Value".
Government Grants
Grants are recognized when there is reasonable assurance that the grant will be received and that any conditions associated with the grant will be met. When grants are received related to Property, plant, and equipment, the Registrants reduce the cost of the assets on their Consolidated Statements of Financial Position, resulting in lower depreciation expense over the life of the associated asset. Grants received related to expenses are reflected as a reduction of the associated expense in the period in which the expense is incurred.Value."
DTE Energy Foundation
DTE Energy's charitable contributions to the DTE Energy Foundation were $12$22 million, $25$43 million, and $18$26 million for the years ended December 31, 2015, 2014,2018, 2017, and 2013,2016, respectively. The DTE Energy Foundation is a non-consolidated not-for-profit private foundation, the purpose of which is to contribute to and assist charitable organizations.

75


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Other Accounting Policies
See the following notes for other accounting policies impacting the Registrants’ Consolidated Financial Statements:
Note Title
74Revenue
8 Asset Retirement Obligations
89 Regulatory Matters
910 Income Taxes
1112 Fair Value
1213 Financial and Other Derivative Instruments
1920Retirement Benefits and Trusteed Assets
21 Stock-Based Compensation

NOTE 3 — NEW ACCOUNTING PRONOUNCEMENTS
Recently Adopted Pronouncements
In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers.Customers (Topic 606), as amended. The objectives of this ASU are to improve upon revenue recognition requirements by providing a single comprehensive model to determine the measurement of revenue and timing of recognition. The core principle is that an entity will recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. This ASU also requiresrequired expanded qualitative and quantitative disclosures regarding the nature, amount, timing, and uncertainty of revenues and cash flows arising from contracts with customers. In July 2015, the FASB deferred implementation of the revenue standard to be effective for the first interim period within annual reporting periods beginning after December 15, 2017. The standard is to be applied retrospectivelyusing either a full retrospective or modified retrospective approach. The Registrants adopted the standard effective January 1, 2018, using the modified retrospective approach. Under the modified retrospective approach, the information for periods prior to the adoption date has not been restated and earlycontinues to be reported under the accounting standards in effect for those periods. As permitted under the standard, the Registrants have elected to apply the guidance only to those contracts that were not completed at January 1, 2018, and have elected not to restate the impacts of any contract modifications made prior to the earliest period presented.
The adoption is permittedof the ASU did not have a significant impact on the Registrants' financial position or results of operations, but required additional disclosures for revenue. See Note 4 to the Consolidated Financial Statements, "Revenue."

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

In March 2017, the FASB issued ASU No. 2017-07, Compensation Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The amendments in this update required that an employer report the service cost component in the preceding year.same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and outside of income from operations. The amendments in this update also allow only the service cost component to be eligible for capitalization when applicable. The Registrants adopted the standard effective January 1, 2018. The standard has been applied retrospectively for the presentation of the service cost component and the other components of net periodic pension cost and net periodic postretirement benefit cost in the income statement and prospectively for the capitalization of the service cost component of net periodic pension cost and net periodic postretirement benefit in assets. As permitted by the standard, the Registrants have used benefit cost amounts disclosed for prior periods as the basis for retrospective application in the income statement. As a result of regulatory mechanisms, the impact to the Consolidated Financial Statements was not material for the year ended December 31, 2018.
In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, as amended. The new guidance is intended to improve the recognition and measurement of financial instruments. The guidance primarily impacts accounting for equity investments in unconsolidated entities (other than those accounted for using the equity method of accounting) and financial liabilities under the fair value option. The guidance requires equity investments to be generally measured at fair value, with subsequent changes in fair value recognized in net income. The guidance requires entities to make a cumulative-effect adjustment to the Statements of Financial Position as of the beginning of the first reporting period in which the guidance is effective. The Registrants adopted the standard effective January 1, 2018. Upon adoption, DTE Energy and DTE Electric recorded a cumulative-effect adjustment to reclassify $5 million and $3 million of unrealized gains from Accumulated other comprehensive income (loss) to Retained earnings, respectively.
In March 2018, the FASB issued ASU No. 2018-05, Income Taxes (Topic 740): Amendments to SEC paragraphs pursuant to SEC Staff Accounting Bulletin No. 118. The Amendments in this update add various SEC paragraphs pursuant to the issuance of SEC Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118). SAB 118 directs taxpayers to consider the implications of the TCJA as provisional when it does not have the necessary information available, prepared, or analyzed in reasonable detail to complete its accounting for the change in the tax law. As described in Note 10 to the Consolidated Financial Statements, "Income Taxes," within the combined DTE Energy and DTE Electric 2017 Annual Report on Form 10-K and in accordance with SAB 118, the Registrants recorded amounts that were considered provisional. During the year ended December 31, 2018, DTE Energy and DTE Electric finalized their SAB 118 analysis and recorded true-up adjustments to the remeasurement of deferred taxes of $21 million and $7 million, respectively. The impact of the true-up adjustments was an increase in Income Tax Expense, of which $17 million was attributable to the regulated utilities and increased Regulatory liabilities.The true-up adjustments were a result of further analysis for items subject to further consideration at December 31, 2017, under SAB 118 and primarily related to timing differences not recoverable from DTE Electric and DTE Gas customers.
Recently Issued Pronouncements
In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), as amended. This guidance requires a lessee to account for leases as finance or operating leases, and disclose key information about leasing arrangements. Both types of leases will result in the lessee recognizing a right-of-use asset and a corresponding lease liability on its balance sheet, with differing methodology for income statement recognition, depending on the lease classification. The Registrants will adopt the standard on January 1, 2019. The standard allows lessees and lessors to apply either, 1) a modified retrospective approach for leases existing or entered into after the beginning of the earliest comparative period in the Consolidated Financial Statements, or 2) a prospective transition approach for leases existing as of January 1, 2019 with a cumulative effect adjustment to be recorded to retained earnings. The Registrants will apply the standard on a prospective basis. The Registrants will elect the package of practical expedients allowing entities to not reassess whether an agreement is a lease, to carryforward the existing lease classification, and to not reassess initial direct costs associated with existing leases. These practical expedients apply to leases that commenced prior to January 1, 2019. The Registrants will also elect to exclude leases from the balance sheet that are for a period of one year or less, as well as, the practical expedient allowing entities to not evaluate land easements under the new guidance at adoption if they were not previously accounted for as leases.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

A third-party software tool has been implemented that will assist with the initial adoption and ongoing compliance of the standard. The Registrants are currentlyimplementing new business processes, internal controls, and accounting policies. The Registrants are in the process of drafting disclosures to satisfy the standard's requirements. In addition, the Registrants are continuing to monitor utility industry implementation guidance and interpretation. While the Registrants expect an increase in assets and liabilities, as well as additional disclosures, they are still assessing the impact of this ASU on their Consolidated Financial Statements.
In February 2015,June 2016, the FASB issued ASU No. 2015-02, 2016-13,Amendments Financial Instruments — Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The amendments in this update replace the incurred loss impairment methodology in current generally accepted accounting principles with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. Entities will apply the Consolidation Analysis,new guidance as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which changes the analysis that a reporting entity must perform to determine whether it should consolidate certain types of legal entities.guidance is adopted. The ASU affects (1) limited partnerships and similar legal entities, (2) evaluating fees paid to a decision maker or a service provider as a variable interest, (3) the effect of fee arrangements on the primary beneficiary determination, (4) the effect of related parties on the primary beneficiary determination, and (5) certain investment funds. It is effective for the Registrants for the first interim period within annual reporting periods beginning after December 15, 20152019, and earlyinterim periods therein. Early adoption is permitted. The Registrants are currently assessing the impact of this ASUstandard on their Consolidated Financial Statements.
In April 2015,February 2018, the FASB issued ASU No. 2015-03,2018-02, Simplifying the PresentationIncome Statement Reporting Comprehensive Income (Topic 220): Reclassification of Debt Issuance CostsCertain Tax Effects from Accumulated Other Comprehensive Income. This ASU requires that debt issuance costs relatedThe amendments in this update allow a reclassification from accumulated other comprehensive income to a recognized debt liability be presented in the balance sheet as a direct deductionretained earnings for stranded tax effects resulting from the carrying amount of that debt liability, consistent with debt discounts. ThisTCJA. The amendments in this update also require entities to disclose their accounting policy for releasing income tax effects from accumulated other comprehensive income. The ASU is effective for reporting periodsthe Registrants for fiscal years beginning after December 15, 20152018, and interim periods therein. It is to be applied retrospectively and earlyEarly adoption is permitted. HadThe Registrants are currently assessing the Registrants early adoptedimpact of this ASU it would have decreased assets and liabilitiesstandard on DTE Energy’s and DTE Electric’stheir Consolidated Statements of Financial Position by $74 million and $36 million, respectively, at December 31, 2015, and $73 million and $35 million, respectively, at December 31, 2014.Statements.
In July 2015,August 2018, the FASB issued ASU No. 2015-11,2018-13, Fair Value Measurements (Topic 820): Disclosure Framework Inventory (Topic 330), SimplifyingChanges to the Disclosure Requirements for Fair Value Measurement of Inventory. The ASU replacesamendments in this update modify the current lower of cost or market test with a lower of cost or net realizabledisclosure requirements on fair value test when cost is determined on a first-in, first-out or average cost basis.measurements in Topic 820. The standardASU is effective for public entitiesthe Registrants for annual reporting periodsfiscal years beginning after December 15, 2016,2019, and interim periods therein. It is to be applied prospectively and earlyEarly adoption is permitted. The ASU will not have a significantRegistrants are currently assessing the impact of this standard on the Registrants'their Consolidated Financial Statements.
In November 2015,August 2018, the FASB issued ASU No. 2015-17, 2018-14,Balance Sheet Classification of Deferred Taxes Compensation Retirement Benefits Defined Benefit Plans (Subtopic 715-20): Disclosure Framework Changes to the Disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. This ASU requiresThe amendments in this update modify the disclosure requirements for employers that all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. Thissponsor defined benefit pension or other postretirement plans. The ASU is effective for reporting periods beginningthe Registrants for fiscal years ending after December 15, 2016, including interim periods therein. It may be applied either prospectively or retrospectively, and early2020. Early adoption is permitted. The Registrants adopted this ASU at December 31, 2015. The adoptionare currently assessing the impact of this standard on their Consolidated Financial Statements.
In August 2018, the FASB issued ASU impacted DTE Energy’sNo. 2018-15, Intangibles Goodwill and DTE Electric’sOther Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract. The amendments in this update align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). The ASU is effective for the Registrants for fiscal years beginning after December 15, 2019, and interim periods therein. Early adoption is permitted. The Registrants are currently assessing the impact of this standard on their Consolidated StatementsFinancial Statements.
In October 2018, the FASB issued ASU No. 2018-17, Consolidation (Topic 810):Targeted Improvements to Related Party Guidance for Variable Interest Entities. The amendments in this update modify the requirements for determining whether a decision-making fee is a variable interest and require reporting entities to consider indirect interests held through related parties under common control on a proportional basis. The ASU is effective for the Registrants for fiscal years beginning after December 15, 2019, and interim periods therein. Early adoption is permitted. The Registrants are currently assessing the impact of this standard on their Consolidated Financial Position by decreasing assets and liabilities for 2014 by $75 million and $2 million, respectively.Statements.


76


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

NOTE 4 — ACQUISITIONS AND EXIT ACTIVITIESREVENUE
AcquisitionsSignificant Accounting Policy
On January 21, 2015,Upon the adoption of Topic 606, revenue is measured based upon the consideration specified in a contract with a customer at the time when performance obligations are satisfied. Under Topic 606, a performance obligation is a promise in a contract to transfer a distinct good or service or a series of distinct goods or services to the customer. The Registrants recognize revenue when performance obligations are satisfied by transferring control over a product or service to a customer. The Registrants have determined control to be transferred when the product is delivered or the service is provided to the customer. For the year ended December 31, 2018, recognition of revenue for the Registrants subsequent to the adoption of Topic 606 is substantially similar in amount and approach to that prior to adoption.
Rates for DTE Electric closed on an acquisitionand DTE Gas include provisions to adjust billings for fluctuations in fuel and purchased power costs, cost of a 732 MW simple-cycle natural gas, facilityand certain other costs. Revenues are adjusted for differences between actual costs subject to reconciliation and the amounts billed in Carson City, Michigan from current rates. Under or over recovered revenues related to these cost recovery mechanisms are included in Regulatory assets or liabilities on the Registrants' Consolidated Statements of Financial Position and are recovered or returned to customers through adjustments to the billing factors.
For discussion of derivative contracts, see Note 13 to the Consolidated Financial Statements, "Financial and Other Derivative Instruments."
Disaggregation of Revenue
The LS Power Group.The facility will serve to meet customer needs during periodsfollowing is a summary of peak demand. revenues disaggregated by segment for DTE Energy:
 2018
 (In millions)
Electric(a)
 
Residential$2,494
Commercial1,794
Industrial690
Other320
Total Electric operating revenues(b)
$5,298
  
Gas 
Gas sales$1,055
End User Transportation232
Intermediate Transportation58
Other91
Total Gas operating revenues(c)
$1,436
  
Other segment operating revenues 
Gas Storage and Pipelines$485
Power and Industrial Projects(d)
$2,204
Energy Trading(e)
$5,557

(a)Revenues under the Electric segment generally represent those of DTE Electric.
(b)Includes $21 million under Alternative Revenue Programs and $20 million of other revenues, which are both outside the scope of Topic 606 for the year ended December 31, 2018.
(c)Includes $2 million under Alternative Revenue Programs and $7 million of other revenues, which are both outside the scope of Topic 606 for the year ended December 31, 2018.
(d)Includes revenues outside the scope of Topic 606 primarily related to $125 million of contracts accounted for as leases for the year ended December 31, 2018.
(e)Includes revenues outside the scope of Topic 606 primarily related to $4.5 billion of derivatives for the year ended December 31, 2018.

DTE Energy Company — DTE Electric has completed its valuation analysisCompany
Combined Notes to arrive atConsolidated Financial Statements — (Continued)

Nature of Goods and Services
The following is a description of principal activities, separated by reportable segments, from which DTE Energy generates revenue. For more detailed information about reportable segments, see Note 22 to the fair value ofConsolidated Financial Statements, “Segment and Related Information.”
The Registrants have contracts with customers which may contain more than one performance obligation. When more than one performance obligation exists in a contract, the assets acquired. The cash consideration and total purchase price of approximately $241 million wasunder the contract is allocated to the performance obligations based on the underlying fair value of the assets acquired, which was primarily Property, plant, and equipment. The pro forma results of operations have not been presented forrelative standalone selling price. DTE Electric as the effects of the acquisition were not material to either Registrant's Consolidated Statements of Operations.
On October 1, 2015, DTE Electric closed on an acquisition of a 350 MW simple-cycle natural gas facility in East China Township, Michigan from a non-utility affiliate of DTE Energy. The facility will serve to meet customer needs during periods of peak demand. DTE Electric has completed its purchase accounting. The cash consideration and total purchase price of approximately $69 million wasEnergy generally determines standalone selling prices based on the net book valueprices charged to customers or the use of the assets acquired, which was primarily Property, plant, and equipment.adjusted market assessment approach. The pro forma results of operations have not been presented for DTE Electric asadjusted market assessment approach involves the effectsevaluation of the acquisition were not material to its Consolidated Statements of Operations.
Exit Activities
On December 17, 2015,market in which DTE Energy announcedsells goods or services and estimating the closureprice that a customer in that market would be willing to pay.
Under Topic 606, when a customer simultaneously receives and consumes the product or service provided, revenue is considered to be recognized over time. Alternatively, if it is determined that the criteria for recognition of revenue over time is not met, the revenue is considered to be recognized at a point in time.
Electric
Electric consists principally of DTE Electric. Electric revenues are primarily comprised of the Shenango coke battery plantsupply and delivery of electricity, and related capacity. Revenues are primarily associated with cancelable contracts, with the exception of certain long-term contracts with commercial and industrial customers. Revenues, including estimated unbilled amounts, are generally recognized over time based upon volumes delivered or through the passage of time ratably based upon providing a stand-ready service. The Registrants have determined that the above methods represent a faithful depiction of the transfer of control to the customer. Unbilled revenues are typically determined utilizing approved tariff rates and estimated meter volumes. Estimated unbilled amounts recognized in responserevenue are subject to a sharp downturnadjustment in the North American steel industry. The plant, which is includedfollowing reporting period as actual volumes by customer class are known. Revenues are typically subject to tariff rates based upon customer class and type of service, and are billed and received monthly. Tariff rates are determined by the MPSC on a per unit or monthly basis.
Gas
Gas consists principally of DTE Gas. Gas revenues are primarily comprised of the supply and delivery of natural gas, and other services including storage, transportation, and appliance maintenance. Revenues are primarily associated with cancelable contracts with the exception of certain long-term contracts with commercial and industrial customers. Revenues, including estimated unbilled amounts, are generally recognized over time based upon volumes delivered or through the passage of time ratably based upon providing a stand-ready service. DTE Energy has determined that the above methods represent a faithful depiction of the transfer of control to the customer. Unbilled revenues are typically determined using both estimated meter volumes and estimated usage based upon the number of unbilled days and historical temperatures. Estimated unbilled amounts recognized in revenue are subject to adjustment in the following reporting period as actual volumes by customer class and service type are known. Revenues are typically subject to tariff rates or other rates subject to regulatory oversight and are billed and received monthly. Tariff rates are determined by the MPSC on a per unit or monthly basis.
Gas Storage and Pipelines
Gas Storage and Pipelines revenues generally consist of services related to the gathering, transportation, and storage of natural gas. Contracts are primarily long-term in nature. Revenues, including estimated unbilled amounts, are generally recognized over time based upon services provided or through the passage of time ratably based upon providing a stand-ready service. DTE Energy has determined that the above methods represent a faithful depiction of the transfer of control to the customer. Revenues are typically billed and received monthly. Pricing for such revenues may consist of demand rates, commodity rates, transportation rates, and other associated fees. Consideration may consist of both fixed and variable components. Generally, uncertainties in the variable consideration components are resolved and revenues are known at the time of recognition.
Power and Industrial Projects
Power and Industrial Projects segment, is located in Pittsburgh, PA. As a resultrevenues include contracts accounted for as leases which are outside of the closure, scope of Topic 606. For performance obligations within the scope of Topic 606, the timing of revenue recognition is dependent upon when control over the associated product or service is transferred.

DTE Energy recorded a one-time pre-tax non-cash impairment charge of $111 million. The charge included $96 millionCompany — DTE Electric Company
Combined Notes to fully impair the long-lived assets, employee severance expenses related to the workforce reduction of approximately 170 employees for $3 million, and other expenses, including write downs of inventory, of $12 million. DTE Energy's coke production has been shifted to a larger, more efficient coke battery plant in theConsolidated Financial Statements — (Continued)

Revenues at Power and Industrial Projects, segment. Productionwithin the scope of Topic 606, generally consist of sales of refined coal, coal, blast furnace coke, coke oven gas, electricity, equipment maintenance services, and other energy related products and services. Revenues, including estimated unbilled amounts, for the sale of blast furnace coke are generally recognized at a point in time when the product is delivered, which represents the transfer of control to the customer. Other revenues are generally recognized over time based upon services provided or through the passage of time ratably based upon providing a stand-ready service. DTE Energy has determined that the above methods represent a faithful depiction of the transfer of control to the customer. Market based pricing structures exist in such contracts including adjustments for consumer price or other indices. Consideration may consist of both fixed and variable components. Generally, uncertainties in the variable consideration components are resolved and revenues are known at the time of recognition. Billing terms vary and are generally monthly with payment terms typically within 30 days following billing.
Energy Trading
Energy Trading revenues consist primarily of derivative contracts outside of the scope of Topic 606. For performance obligations within the scope of Topic 606, the timing of revenue recognition is dependent upon when control over the associated product or service is transferred.
Revenues, including estimated unbilled amounts, within the scope of Topic 606 arising from the Shenango coke battery plant ceasedsale of natural gas, electricity, power capacity, and other energy related products are generally recognized over time based upon volumes delivered or through the passage of time ratably based upon providing a stand-ready service. DTE Energy has determined that the above methods represent a faithful depiction of the transfer of control to the customer. Revenues are known at the time of recognition. Payment for the aforementioned revenues is generally due from customers in January 2016.the month following delivery.
ARevenues associated with RECs are recognized at a point in time when control of the RECs are transferred to the customer which is deemed to be when the subject RECs are entered for transfer to the customer in the applicable regulatory tracking system. Revenues associated with RECs under a wholesale full requirements power contract are deferred until control has been transferred. The deferred revenues represent a contract liability for which payment has been received and the amounts have been estimated using the adjusted market assessment approach. With the exception of RECs, generally all other performance obligations associated with wholesale full requirements power contracts are satisfied over time in conjunction with the delivery of power. At the time power is delivered, DTE Energy may not have control over the RECs as the RECs are not self-generated and may not yet have been procured resulting in deferred revenues.
Deferred Revenue
The following is a summary of the charges in the Consolidated Statements of Operations resulting from DTE Energy's exit activities is shown below:deferred revenue activity:
 2015
 (In millions)
Fuel, purchased power, and gas — non-utility$5
Operation and maintenance10
Asset (gains) losses and impairments, net96
Total Exit Activity Charges$111
 DTE Energy
 (In millions)
Beginning Balance, January 1, 2018$56
Increases due to cash received or receivable, excluding amounts recognized as revenue during the period48
Revenue recognized that was included in the deferred revenue balance at the beginning of the period(30)
Ending Balance, December 31, 2018$74
ForThe deferred revenues at DTE Energy generally represent amounts accrued at December 31, 2015paid by or receivable from customers for which the associated performance obligation has not yet been satisfied.
Deferred revenues include amounts associated with REC performance obligations under certain wholesale full requirements power contracts. Deferred revenues associated with RECs are recognized as revenue when control of the RECs has transferred.
Other performance obligations associated with deferred revenues include providing products and services related to customer prepayments. Deferred revenues associated with these exit activities, products and services are recognized when control has transferred to the customer.

DTE Energy expects future cash payments of approximately $7 millionCompany — DTE Electric Company
Combined Notes to be made in 2016. DTE Energy anticipates incurring additional costs, including environmental remediation costs, in connection with the closure. An estimate of the amount of additional costs and timing of the activities cannot be determined at December 31, 2015 as alternatives are currently being evaluated, however, the likelihood of these costs being material to DTE Energy's Consolidated Financial Statements is remote.— (Continued)


The following table represents deferred revenue amounts for DTE Energy that are expected to be recognized as revenue in future periods:
77

 DTE Energy
 (In millions)
2019$46
20201
20215
20227
20235
2024 and thereafter10
 $74
Transaction Price Allocated to the Remaining Performance Obligations
In accordance with optional exemptions available under Topic 606, the Registrants did not disclose the value of unsatisfied performance obligations for (1) contracts with an original expected length of one year or less, (2) with the exception of fixed consideration, contracts for which revenue is recognized at the amount to which the Registrants have the right to invoice for goods provided and services performed, and (3) contracts for which variable consideration relates entirely to an unsatisfied performance obligation.
Such contracts consist of varying types of performance obligations across the segments, including the supply and delivery of energy related products and services. Contracts with variable volumes and/or variable pricing, including those with pricing provisions tied to a consumer price or other index, have also been excluded as the related consideration under the contract is variable at inception of the contract. Contract lengths vary from cancelable to multi-year.
The Registrants expect to recognize revenue for the following amounts related to fixed consideration associated with remaining performance obligations in each of the future periods noted:
 DTE Energy DTE Electric
 (In millions)
2019$267
 $8
2020263
 
2021219
 
2022172
 
2023139
 
2024 and thereafter658
 
 $1,718
 $8
Other Matters
DTE Energy and DTE Electric have recognized charges of $140 million and $85 million related to expense recognized for estimated uncollectible accounts receivable for the year ended December 31, 2018, respectively.


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

NOTE 5 — GOODWILL
DTE Energy has goodwill resulting from business combinations.
The following is the summary of change in the carrying amount of goodwill for the years ended December 31:
 2018 2017
 (In millions)
Balance as of January 1$2,293
 $2,286
Goodwill attributable to Gas Storage and Pipelines 2016 acquisition of AGS and SGG
 7
Balance at December 31$2,293
 $2,293

NOTE 56 — PROPERTY, PLANT, AND EQUIPMENT
The following is a summary of Property, plant, and equipment by classification as of December 31:
2015 20142018 2017
Property, plant, and equipment(In millions)(In millions)
DTE Electric      
Generation$11,767
 $10,712
$11,027
 $12,166
Distribution7,816
 7,414
9,153
 8,637
Other1,808
 1,679
2,567
 2,169
Total DTE Electric21,391

19,805
22,747

22,972
DTE Gas      
Distribution3,124
 2,946
3,823
 3,523
Storage453
 448
548
 533
Transmission and other890
 863
1,204
 1,118
Total DTE Gas4,467
 4,257
5,575
 5,174
Non-utility and other2,263
 2,476
3,488
 3,278
Total DTE Energy28,121
 26,538
31,810
 31,424
Less accumulated depreciation and amortization   
Accumulated depreciation and amortization   
DTE Electric      
Generation(4,346) (3,863)(3,609) (4,403)
Distribution(2,707) (2,822)(2,974) (2,914)
Other(593) (531)(727) (667)
Total DTE Electric(7,646) (7,216)(7,310) (7,984)
DTE Gas      
Distribution(1,163) (1,130)(1,283) (1,238)
Storage(147) (142)(165) (159)
Transmission and other(370) (363)(404) (384)
Total DTE Gas(1,680) (1,635)(1,852) (1,781)
Non-utility and other(761) (867)(998) (938)
Total DTE Energy(10,087) (9,718)(10,160) (10,703)
Net DTE Energy Property, plant, and equipment$18,034
 $16,820
$21,650
 $20,721
Net DTE Electric Property, plant, and equipment$13,745
 $12,589
$15,437
 $14,988

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following is a summary of the Registrants' AFUDC and interest capitalized was approximately $34 million and $37 million for DTE Energy for the years ended December 31, 2015 and 2014, respectively, including AFUDC capitalized of approximately $31 million and $32 million for DTE Electric for the years ended December 31, 2015 and 2014, respectively.31:
 DTE Energy DTE Electric
 2018 2017 2018 2017
 (In millions)
Allowance for debt funds used during construction and interest capitalized$15
 $13
 $9
 $8
Allowance for equity funds used during construction28
 23
 19
 18
Total$43
 $36
 $28
 $26
The composite depreciation rate for DTE Electric was approximately 3.7%, 3.6%, and 3.5% in 20152018, 2017 and 3.4% in 2014 and 2013.2016, respectively. The composite depreciation rate for DTE Gas was 2.6%2.7%, in 20152018 and 2017, and 2.4% in 2014 and 2013.2016. The average estimated useful life for each major class of utility Property, plant, and equipment as of December 31, 20152018 follows:
  Estimated Useful Lives in Years
Utility Generation Distribution Storage
DTE Electric 40 41 N/A
DTE Gas N/A 50 53
The estimated useful lives for DTE Electric's Other utility assets range from 53 to 62 years, while the estimated useful lives for DTE Gas' Transmission and other utility assets range from 5 to 70 years. The estimated useful lives for major classes of DTE Energy's non-utility assets and facilities range from 3 to 5583 years.

78


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following is a summary of Depreciation and amortization expense for DTE Energy, including DTE Electric:Energy:
2015 2014 20132018 2017 2016
(In millions)(In millions)
Property, plant, and equipment$740
 $683
 $630
$912
 $865
 $783
Regulatory assets and liabilities150
 159
 163
212
 165
 193
Securitized regulatory assets (a)(38) 303
 301
$852
 $1,145
 $1,094
$1,124
 $1,030
 $976
The following is a summary of Depreciation and amortization expense for DTE Electric:
2015 2014 20132018 2017 2016
(In millions)(In millions)
Property, plant, and equipment$545
 $489
 $457
$657
 $620
 $582
Regulatory assets and liabilities126
 135
 138
179
 133
 168
Securitized regulatory assets (a)(38) 303
 301
$633
 $927
 $896
$836
 $753
 $750

(a)Securitization surcharges ended in December 2014 with remaining over recovery refunded to customers in 2015. Securitization bonds were paid and Securitization regulatory assets amortization was completed in 2015. The $38 million credit represents the final adjustments to close out the Securitization program.
Capitalized software costs are classified as Property, plant, and equipment and the related amortization is included in accumulated depreciation and amortization on the Registrants' Consolidated Financial Statements. The Registrants capitalize the costs associated with computer software developed or obtained for use in their businesses. The Registrants amortize capitalized software costs on a straight-line basis over the expected period of benefit, ranging from 31 to 15 years for DTE Energy and 53 to 15 years for DTE Electric. The following balances for capitalized software relate to DTE Energy, including DTE Electric:
 Year Ended December 31,
 2015 2014 2013
 (In millions)
Amortization expense of capitalized software$98
 $77
 $71
Gross carrying value of capitalized software$770
 $668
  
Accumulated amortization of capitalized software$439
 $335
  
The following balances for capitalized software relate to DTE Electric:Energy:
Year Ended December 31,Year Ended December 31,
2015 2014 20132018 2017 2016
(In millions)(In millions)
Amortization expense of capitalized software$80
 $71
 $64
$108
 $101
 $89
Gross carrying value of capitalized software$664
 $590
  $905
 $890
  
Accumulated amortization of capitalized software$369
 $293
  $534
 $500
  
Property under capital leases for the Registrants is as follows:
 DTE Energy DTE Electric
 2015 2014 2015 2014
 (In millions)
Gross property under capital leases$48
 $35
 $22
 $9
Accumulated amortization of property under capital leases$26
 $27
 $1
 $5

79


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)


The following balances for capitalized software relate to DTE Electric:
 Year Ended December 31,
 2018 2017 2016
 (In millions)
Amortization expense of capitalized software$101
 $93
 $83
Gross carrying value of capitalized software$799
 $774
  
Accumulated amortization of capitalized software$463
 $423
  
DTE Energy is the lessor under certain operating leases for energy facilities and related equipment. Property under operating leases for DTE Energy is as follows:
 DTE Energy
 2018 2017
 (In millions)
Gross property under operating leases$447
 $327
Accumulated amortization of property under operating leases$148
 $108
The Registrants are the lessee under certain capital leases related to software and information technology related equipment. Property under capital leases for the Registrants is as follows:
 DTE Energy DTE Electric
 2018 2017 2018 2017
 (In millions)
Gross property under capital leases$18
 $44
 $18
 $18
Accumulated amortization of property under capital leases$7
 $38
 $7
 $12

NOTE 67 — JOINTLY-OWNED UTILITY PLANT
DTE Electric has joint ownership interest in two power plants, Belle River and Ludington Hydroelectric Pumped Storage. DTE Electric’s share of direct expenses of the jointly-owned plants are included in Fuel, purchased power, and gas utility and Operation and maintenance expenses in the DTE Energy Consolidated Statements of Operations and Fuel and purchased power utility and Operation and maintenance expenses in the DTE Electric Consolidated Statements of Operations. Ownership
DTE Electric's ownership information of the two utility plants as of December 31, 20152018 was as follows:
Belle River 
Ludington
Hydroelectric
Pumped Storage
Belle River 
Ludington
Hydroelectric
Pumped Storage
In service date1984-1985 1973
Total plant capacity1,270 MW 1,955 MW
In-service date1984-1985 1973
Ownership interest(a) 49%81% 49%
Investment in Property, plant, and equipment (in millions)$1,779
 $443
$1,819
 $586
Accumulated depreciation (in millions)$1,053
 $154
$1,068
 $187

(a)DTE Electric's ownership interest is 63% in Unit No. 1, 81% of the facilities applicable to Belle River used jointly by the Belle River and St. Clair Power Plants and 75% in common facilities used at Unit No. 2.
Belle River
The Michigan Public Power Agency (MPPA) has an ownership interestinterests in Belle River Unit No. 1 and other related facilities. The MPPA is entitled to 19% of the total capacity and energy of the plant and is responsible for the same percentage of the plant’s operation, maintenance, and capital improvement costs.


Ludington Hydroelectric Pumped Storage
Consumers Energy Company has an ownership interest in the Ludington Hydroelectric Pumped Storage Plant. Consumers Energy is entitled to 51% of the total capacity and energy of the plant and is responsible for the same percentage of the plant’s operation, maintenance, and capital improvement costs.

NOTE 78 — ASSET RETIREMENT OBLIGATIONS
DTE Electric has a legal retirement obligation for the decommissioning costs for its Fermi 1 and Fermi 2 nuclear plants, dismantlement of facilities located on leased property, and various other operations. DTE Electric has conditional retirement obligations for asbestos and PCB removal at certain of its power plants and various distribution equipment. DTE Gas has conditional retirement obligations for gas pipelines, certain service centers, compressor and gate stations. The Registrants recognize such obligations as liabilities at fair market value when they are incurred, which generally is at the time the associated assets are placed in service. Fair value is measured using expected future cash outflows discounted at the Registrants' credit-adjusted risk-free rate. For its utility operations, the Registrants recognize in the Consolidated Statements of Operations removal costs in accordance with regulatory treatment. Any differences between costs recognized related to asset retirement and those reflected in rates are recognized as either a Regulatory asset or liability on the Consolidated Statements of Financial Position.
If a reasonable estimate of fair value cannot be made in the period in which the retirement obligation is incurred, such as for assets with indeterminate lives, the liability is recognized when a reasonable estimate of fair value can be made. Natural gas storage system and certain other distribution assets for DTE Gas and substations, manholes, and certain other distribution assets for DTE Electric have an indeterminate life. Therefore, no liability has been recorded for these assets.

80


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

A reconciliation of the asset retirement obligations for 20152018 follows:
 DTE Energy DTE Electric
 (In millions)
Asset retirement obligations at December 31, 2014$1,962
 $1,796
Accretion119
 111
Liabilities incurred33
 33
Revision in estimated cash flows80
 80
Asset retirement obligations at December 31, 2015$2,194
 $2,020
The Revision in estimated cash flows was principally attributed to the impact of the Coal Combustion Residuals on DTE Electric's coal ash storage facility AROs. Refer to Note 17 to the Consolidated Financial Statements, "Commitments and Contingencies", for discussion of the implications of the Coal Combustion Residuals.
 DTE Energy DTE Electric
 (In millions)
Asset retirement obligations at December 31, 2017$2,320
 $2,125
Accretion140
 129
Liabilities incurred27
 27
Liabilities settled(16) (8)
Revision in estimated cash flows(2) (2)
Asset retirement obligations at December 31, 2018$2,469
 $2,271
Approximately $1.8$2.0 billion of the asset retirement obligations represent nuclear decommissioning liabilities that are funded through a surcharge to electric customers over the life of the Fermi 2 nuclear plant. The NRC has jurisdiction over the decommissioning of nuclear power plants and requires minimum decommissioning funding based upon a formula. The MPSC and FERC regulate the recovery of costs of decommissioning nuclear power plants and both require the use of external trust funds to finance the decommissioning of Fermi 2. Rates approved by the MPSC provide for the recovery of decommissioning costs of Fermi 2 and the disposal of low-level radioactive waste. DTE Electric is continuing to fund FERC jurisdictional amounts for decommissioning even though explicit provisions are not included in FERC rates. DTE Electric believes the MPSC and FERC collections will be adequate to fund the estimated cost of decommissioning. The decommissioning assets, anticipated earnings thereon, and future revenues from decommissioning collections will be used to decommission Fermi 2. DTE Electric expects the liabilities to be reduced to zero at the conclusion of the decommissioning activities. If amounts remain in the trust funds for Fermi 2 following the completion of the decommissioning activities, those amounts will be disbursed based on rulings by the MPSC and FERC.
A portion of the funds recovered through the Fermi 2 decommissioning surcharge and deposited in external trust accounts is designated for the removal of non-radioactive assets and returning the site to greenfield. This removal and greenfielding is not considered a legal liability. Therefore, it is not included in the asset retirement obligation, but is reflected as the Nuclear decommissioning liability. The decommissioning of Fermi 1 is funded by DTE Electric. Contributions to the Fermi 1 trust are discretionary. For additional discussion of Nuclear decommissioning trust fund assets, see Note 1112 to the Consolidated Financial Statements, "Fair Value".Value."


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

NOTE 89 — REGULATORY MATTERS
Regulation
DTE Electric and DTE Gas are subject to the regulatory jurisdiction of the MPSC, which issues orders pertaining to rates, recovery of certain costs, including the costs of generating facilities and regulatory assets, conditions of service, accounting, and operating-related matters. DTE Electric is also regulated by the FERC with respect to financing authorization and wholesale electric activities. Regulation results in differences in the application of generally accepted accounting principles between regulated and non-regulated businesses.
The Registrants are unable to predict the outcome of the unresolved regulatory matters discussed herein. Resolution of these matters is dependent upon future MPSC orders and appeals, which may materially impact the Consolidated Financial Statements of the Registrants.

81


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Regulatory Assets and Liabilities
DTE Electric and DTE Gas are required to record Regulatory assets and liabilities for certain transactions that would have been treated as revenue or expense in non-regulated businesses. Continued applicability of regulatory accounting treatment requires that rates be designed to recover specific costs of providing regulated services and be charged to and collected from customers. Future regulatory changes or changes in the competitive environment could result in the discontinuance of this accounting treatment for Regulatory assets and liabilities for some or all of the Registrants' businesses and may require the write-off of the portion of any Regulatory asset or liability that was no longer probable of recovery through regulated rates. Management believes that currently available facts support the continued use of Regulatory assets and liabilities and that all Regulatory assets and liabilities are recoverable or refundable in the current regulatory environment.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following are balances and a brief description of the Registrants' Regulatory assets and liabilities at December 31:
DTE Energy DTE ElectricDTE Energy DTE Electric
2015 2014 2015 20142018 2017 2018 2017
Assets(In millions)(In millions)
Recoverable pension and other postretirement costs:       
Recoverable pension and other postretirement costs       
Pension$2,112
 $2,284
 $1,592
 $1,743
$1,961
 $2,000
 $1,476
 $1,502
Other postretirement costs256
 234
 198
 191
213
 278
 121
 211
Asset retirement obligation565
 448
 565
 448
778
 569
 778
 569
Recoverable undepreciated costs on retiring plants630
 
 630
 
Removal costs asset407
 299
 407
 299
Recoverable Michigan income taxes248
 267
 203
 220
201
 213
 161
 171
Removal costs asset118
 15
 118
 15
Accrued PSCR/GCR revenue116
 17
 116
 17
Deferred environmental costs69
 75
 
 
Unamortized loss on reacquired debt63
 67
 41
 44
60
 65
 43
 46
Recoverable income taxes related to AFUDC equity51
 41
 41
 35
Energy Waste Reduction incentive49
 39
 39
 30
Nuclear Performance Evaluation and Review Committee Tracker43
 22
 43
 22
Customer360 deferred costs42
 45
 42
 45
Other recoverable income taxes61
 66
 61
 66
23
 26
 23
 26
Deferred environmental costs54
 59
 
 
Transitional Reconciliation Mechanism43
 14
 43
 14
21
 46
 21
 46
Cost to achieve Performance Excellence Process33
 54
 28
 46
Accrued PSCR/GCR revenue12
 61
 
 34
Recoverable income taxes related to Securitized regulatory assets
 19
 
 19
Other159
 139
 137
 119
57
 43
 36
 36
3,724
 3,727
 2,986
 2,959
4,721
 3,778
 3,977
 3,055
Less amount included in Current Assets(32) (76) (17) (46)(153) (55) (148) (50)
$3,692
 $3,651
 $2,969
 $2,913
$4,568
 $3,723
 $3,829
 $3,005
Securitized regulatory assets$
 $34
 $
 $34
DTE Energy DTE ElectricDTE Energy DTE Electric
2015 2014 2015 20142018 2017 2018 2017
Liabilities(In millions)(In millions)
Refundable federal income taxes$2,410
 $2,384
 $1,958
 $1,946
Removal costs liability$291
 $308
 $
 $
253
 265
 
 
TCJA rate reduction liability118
 
 93
 
Negative other postretirement offset101
 80
 79
 67
Renewable energy197
 227
 197
 227
86
 112
 86
 112
Refundable self-implemented rates26
 2
 26
 2
Negative pension offset46
 67
 
 
9
 21
 
 
Accrued PSCR/GCR refund37
 
 15
 
Refundable income taxes23
 33
 
 
Energy optimization10
 24
 
 14
Fermi 2 refueling outage4
 16
 4
 16
4
 15
 4
 15
Securitization over recovery
 71
 
 71
Refundable revenue decoupling/deferred gain
 63
 
 63
Other2
 11
 2
 4
41
 14
 23
 12
$610
 $820
 $218
 $395
3,048
 2,893
 2,269
 2,154
Less amount included in Current Liabilities(41) (153) (19) (150)(126) (18) (98) (17)
$569
 $667
 $199
 $245
$2,922
 $2,875
 $2,171
 $2,137

82


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

As noted below, certain Regulatory assets for which costs have been incurred have been included (or are expected to be included, for costs incurred subsequent to the most recently approved rate case) in DTE Electric's or DTE Gas' rate base, thereby providing a return on invested costs (except as noted). Certain other regulatory assets are not included in rate base but accrue recoverable carrying charges until surcharges to collect the assets are billed. Certain Regulatory assets do not result from cash expenditures and therefore do not represent investments included in rate base or have offsetting liabilities that reduce rate base.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

ASSETS
Recoverable pension and other postretirement costs — Accounting standards for pension and other postretirement benefit costs require, among other things, the recognition in Other comprehensive income of the actuarial gains or losses and the prior service costs that arise during the period but that are not immediately recognized as components of net periodic benefit costs. DTE Electric and DTE Gas record the impact of actuarial gains or losses and prior service costs as a Regulatory asset since the traditional rate setting process allows for the recovery of pension and other postretirement costs. The asset will reverse as the deferred items are amortized and recognized as components of net periodic benefit costs.(a)
Asset retirement obligation — This obligation is for Fermi 2 decommissioning costs. The asset captures the timing differences between expense recognition and current recovery in rates and will reverse over the remaining life of the related plant.(a)
Recoverable pension and other postretirementundepreciated costs on retiring plants — Accounting rules for pension and other postretirement benefit costs require, among other things,Deferral of estimated remaining balances associated with coal power plants expected to be retired within the recognition in Other comprehensive income of the actuarial gains or losses and the prior service costs that arise during the period but that are not immediately recognized as components of net periodic benefit costs. DTE Electric and DTE Gas record the impact of actuarial gains or losses and prior service costs as a Regulatory asset since the traditional rate setting process allows for the recovery of pension and other postretirement costs. The asset will reverse as the deferred items are amortized and recognized as components of net periodic benefit costs. (a)2020 to 2023 time-frame.
Asset retirement obligation
Removal costs asset — Receivable for the recovery of asset removal expenditures in excess of amounts collected from customers.(a) — This obligation is for Fermi 2 decommissioning costs. The asset captures the timing differences between expense recognition and current recovery in rates and will reverse over the remaining life of the related plant. (a)
Recoverable Michigan income taxesIn July 2007, the MBT was enacted by theThe State of Michigan. StateMichigan enacted a corporate income tax resulting in the establishment of state deferred tax liabilities were established for DTE Energy’s utilities and offsettingEnergy's utilities.  Offsetting Regulatory assets were also recorded as the impacts of the deferred tax liabilities will be reflected in rates as the related taxable temporary differences reverse and flow through current income tax expense. In May 2011, the MBT was repealed and the MCIT was enacted. The Regulatory asset was remeasured to reflect the impact of the MCIT tax rate. (a)
Removal costs asset — Receivable for the recovery of asset removal expenditures in excess of amounts collected from customers.
Unamortized loss on reacquired debt — The unamortized discount, premium, and expense related to debt redeemed with a refinancing are deferred, amortized, and recovered over the life of the replacement issue.
Other recoverable income taxes — Income taxes receivable from DTE Electric’s customers representing the difference in property-related deferred income taxes and amounts previously reflected in DTE Electric’s rates. This asset will reverse over the remaining life of the related plant. (a)
Deferred environmental costs — The MPSC approved the deferral of investigation and remediation costs associated with DTE Gas' former MGP sites. Amortization of deferred costs is over a ten-year period beginning in the year after costs were incurred, with recovery (net of any insurance proceeds) through base rate filings. (a)
Transitional Reconciliation Mechanism (TRM) — The MPSC approved the recovery of the deferred net incremental revenue requirement associated with the transition of PLD customers to DTE Electric's distribution system, effective July 1, 2014. Annual reconciliations will be filed and surcharges will be implemented to recover approved amounts.
Cost to achieve Performance Excellence Process (PEP) — The MPSC authorized the deferral of costs to implement the PEP. These costs consist of employee severance, project management, and consultant support. These costs are amortized over a ten-year period beginning with the year subsequent to the year the costs were deferred.
Accrued PSCR/GCR revenue — Receivable for the temporary under-recovery of and carrying costs on fuel and purchased power costs incurred by DTE Electric which are recoverable through the PSCR mechanism and temporary under-recovery of and carrying costs on gas costs incurred by DTE Gas which are recoverable through the GCR mechanism.
Deferred environmental costs — The MPSC approved the deferral of investigation and remediation costs associated with DTE Gas' former MGP sites. Amortization of deferred costs is over a ten-year period beginning in the year after costs were incurred, with recovery (net of any insurance proceeds) through base rate filings.(a)
Unamortized loss on reacquired debt — The unamortized discount, premium, and expense related to debt redeemed with a refinancing are deferred, amortized, and recovered over the life of the replacement issue.
Recoverable income taxes related to Securitized regulatory assetsAFUDC equity — ReceivableAccounting standards for income taxes require recognition of a deferred tax liability for the equity component of AFUDC.  A regulatory asset is required for the future increase in taxes payable related to the equity component of AFUDC that will be recovered from customers through future rates over the remaining life of the related plant.
Energy Waste Reduction incentive — DTE Electric and DTE Gas operate MPSC approved energy waste reduction programs designed to reduce overall energy usage by their customers. The utilities are eligible to earn an incentive by exceeding statutory savings targets. The utilities have consistently exceeded the savings targets and recognize the incentive as a regulatory asset in the period earned.(a)
Nuclear Performance Evaluation and Review Committee Tracker — Deferral and amortization of certain costs associated with oversight and review of DTE Electric's nuclear power generation program, including safety and regulatory compliance, nuclear leadership, nuclear facilities, as well as operation and financial performance, pursuant to the MPSC authorization. The approved five-year amortization period began January 1, 2018, with recovery (net of income taxes to be paid oncarrying costs) through base rate filings.
Customer360 deferred costs — The MPSC approved the non-bypassable securitization bond surcharge. A non-bypassable securitization tax surcharge,deferral and amortization of certain costs associated with implementing Customer360, which ended in December 2014, was in place to recover the income taxis an integrated software application that enables improved interface among customer service, billing, meter reading, credit and collections, device management, account management, and retail access. Amortization of deferred costs over a 14-year period. (a)15-year amortization period began after the billing system was put into operation during the second quarter of 2017.

83


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Securitized regulatory assetsOther recoverable income taxes — Income taxes receivable from DTE Electric's customers representing the difference in property-related deferred income taxes and amounts previously reflected in DTE Electric's rates. This asset will reverse over the remaining life of the related plant.
Transitional Reconciliation Mechanism — The net book balanceMPSC approved the recovery of the Fermi 2 nuclear plant was written off in 1998deferred net incremental revenue requirement associated with the transition of PLD customers to DTE Electric's distribution system, effective July 1, 2014. Annual reconciliations will be filed and an equivalent regulatory asset was established. In 2001, the Fermi 2 regulatory asset and certain other regulatory assets were securitized pursuant to PA 142 and an MPSC order. A non-bypassable securitization bond surcharge, which ended in December 2014, was in placesurcharges will be implemented to recover the Securitized regulatory asset over a 14-year period.approved amounts.

(a)Regulatory assets not earning a return or accruing carrying charges.
LIABILITIES
(a)Refundable federal income taxesRegulatory assets not earning a return or accruing carrying charges. — DTE Electric and DTE Gas' remeasurement of deferred taxes due to the enactment of the TCJA, which reflects the net impact of the tax rate change on cumulative temporary differences expected to reverse after the effective date of January 1, 2018. Refer to "2017 Tax Reform" section below for additional information.
LIABILITIES
Removal costs liability — The amount collected from customers for the funding of future asset removal activities.
TCJA rate reduction liability — Due to the change in the corporate Federal income tax rate from 35% to 21%, DTE Electric and DTE Gas reduced rates charged to customers during 2018. A regulatory liability equal to the difference between revenues billed based on a 35% rate, and revenues based on a 21% rate, was accrued for the period January 1, 2018 through the date the lower rates were implemented. The refund of the liability will commence on January 1, 2019 through June 30, 2019.
Negative other postretirement offset — DTE Electric and DTE Gas' negative other postretirement costs are not included as a reduction to their authorized rates; therefore, DTE Electric and DTE Gas are accruing a Regulatory liability to eliminate the impact on earnings of the negative other postretirement expense accrual. The Regulatory liabilities will reverse to the extent DTE Electric and DTE Gas' other postretirement expense is positive in future years.
Renewable energy — Amounts collected in rates in excess of renewable energy expenditures.
Refundable self-implemented rates — Amounts refundable to customers for base rates implemented from November 1, 2017 to May 1, 2018 in excess of amounts authorized in the June 2018 DTE Electric rate order from the MPSC.
Negative pension offset — DTE Gas' negative pension costs are not included as a reduction to its authorized rates; therefore, DTE Gas is accruing a Regulatory liability to eliminate the impact on earnings of the negative pension expense accrued. This Regulatory liability will reverse to the extent DTE Gas' pension expense is positive in future years.
Accrued PSCR/GCR refund — Liability for the temporary over-recovery of and a return on power supply costs and transmission costs incurred by DTE Electric which are recoverable through the PSCR mechanism and temporary over-recovery of and a return on gas costs incurred by DTE Gas which are recoverable through the GCR mechanism.
Refundable income taxes — Income taxes refundable to DTE Gas' customers representing the difference in property-related deferred income taxes payable and amounts recognized pursuant to MPSC authorization.
Energy optimization (EO) — Amounts collected in rates in excess of energy optimization expenditures.
Fermi 2 refueling outage — Accrued liability for refueling outage at Fermi 2 pursuant to MPSC authorization.
Securitization over recovery — Over recovery of securitization bond expenses.
Refundable revenue decoupling/deferred gain — Amounts were originally accrued as refundable to DTE Electric customers for the change in revenue resulting from the difference between actual average sales per customer compared to the base level of average sales per customer established by the MPSC. In 2012, the MCOA issued a decision reversing the MPSC's decision to authorize a RDM for DTE Electric. The revenue decoupling liability was reversed and, after receiving an order from the MPSC to defer the resulting gain for future amortization, DTE Electric created a regulatory liability representing its obligation to refund the gain. The deferred gain was amortized into earnings in 2014 and 2015.
20142017 Electric Rate Case Filing
DTE Electric filed a rate case with the MPSC on DecemberApril 19, 20142017 requesting an increase in base rates of $370$231 million based on a projected twelve-month period ending June 30, 2016. The requested increase in base rates was due primarily to an increase in net plant resulting from infrastructure investments, plant acquisitions, environmental compliance, and reliability improvement projects. The rate filing also included projected changes in sales, working capital, operation and maintenance expenses, return on equity, and capital structure.October 31, 2018. On JulyNovember 1, 2015,2017, DTE Electric realized an annual revenue increase of $230 million consisting of $190 million of self-implemented a base rate increase related to the December 19, 2014 rate request and $40 million associated with the required elimination of a credit surcharge.$125 million. On December 11, 2015,April 18, 2018, the MPSC issued an order approving an annual revenue increase of $238$65.2 million for service rendered on or after December 17, 2015.May 1, 2018. The rate order also provided forMPSC authorized a reduction of the return on equity from 10.5% to 10.3% on a capital structure of 50% debt and 50% equity.10.0%. On December 22, 2015, DTE Electric petitioned the MPSC for a rehearing and clarification of several issues related to the December 11, 2015 MPSC rate order. The three main issues addressed in the rehearing request were related to the recovery of the cost of the operating license for Fermi 3, the capitalization of the cost of tree trimming, and costs related to certain land and a building located near DTE Electric's Detroit headquarters. On January 19, 2016,June 28, 2018, the MPSC issued an order authorizingon a rehearing granting in part and denying in part, petitions for rehearings of DTE Electric and other intervenors. As a result, the approved addition to begin amortizationbase rates increased from $65.2 million to $74.4 million. In August 2018, DTE Electric filed to refund its customers $26.2 million, inclusive of interest, based on their pro rata share of the cost ofrevenue collected through the Fermi 3 operating license over a 20-year period without a return on the unamortized balance. The MPSC denied the capitalization of the tree trimming costs and the cost relatedself-implementation surcharge in effect from November 1, 2017 to the land and building.May 1, 2018. DTE Electric has recorded a disallowance of $10 million related to tree trim costs in the fourth quarter of 2015 which was previously capitalizedrefund liability as of September 30, 2015. The land and building have economic value independent of recovery through rates and therefore no impairment charge was recorded for these assets. The MPSC order also stated that any changes to the revenue deficiency will be addressed in a final rehearing order in this case.December 31, 2018.

84


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

20162018 Electric Rate Case Filing
DTE Electric filed a rate case with the MPSC on February 1, 2016July 6, 2018 requesting an increase in base rates of $344$328 million based on a projected twelve-month period ending July 31, 2017.April 30, 2020. The requested increase in base rates is primarily due primarily to an increase in net plant resulting from infrastructure investments, environmental compliance,depreciation expense, as requested in the 2016 DTE Electric Depreciation Case Filing, and reliability improvement projects. The rate filing also requests an increase in return on equity from 10.0% to 10.5% and includes projected changes in sales, operation and maintenance expenses, and working capital. TheIn addition, the rate filing also requests an increaseInfrastructure Recovery Mechanism to recover the incremental revenue requirement associated with certain distribution, fossil generation, and nuclear generation capital expenditures through 2022. Finally, as noted in return on equity from 10.3% to 10.5% on a capital structure of 50% equity and 50% debt.the 2017 Tax Reform section below, DTE Electric anticipates self-implementing a rate increaseaddressed Calculation C in August 2016 with anthis filing. A final MPSC order in this case is expected by February 2017.May 2019.
PSCR ProceedingsCertificate of Necessity
The PSCR process is designed to allowOn July 31, 2017, DTE Electric filed a request for authority to recover allbuild a 1,100 megawatt natural gas fueled combined cycle generation facility at DTE Electric's Belle River Power Plant. DTE Electric requested the MPSC to issue three CONs for the following: (1) power supplied by the proposed project is needed, (2) the size, fuel type, and other design characteristics of its power supply costs if incurred underthe proposed project represent the most reasonable and prudent policiesmeans of meeting the power need, and practices.(3) the estimated capital costs of $989 million for the proposed project will be recoverable in rates from DTE Electric's power supply costs include fuel and related transportation costs, purchased and net interchange power costs, nitrogen oxide and sulfur dioxide emission allowances costs, urea costs, transmission costs, and MISO costs.customers. The MPSC reviews these costs, policies, and practices for prudence in annual plan and reconciliation filings.
2012 PSCR Year — In March 2013, DTE Electric filed its 2012 PSCR reconciliation that included purchased power costs related to the manual shutdown of the Fermi 2 nuclear power plant in June 2012 caused by the failure of one of the plant's two non-safety related feed-water pumps. The plant was restarted on July 30, 2012, which restored production to approximately 68% of full capacity. In September 2013, the repair to the plant was completed and production was returned to full capacity. DTE Electric was able to purchase sufficient power from MISO to continue to provide uninterrupted service to customers. On June 30, 2015, the MPSC issued an order that disallowed approximately $19 million of Fermi 2 related purchased power costs.April 27, 2018 approving DTE Electric's request for the three CONs with recoverable amounts through rates up to $951.8 million. In August 2018, DTE Electric recorded the impact of this disallowance in the second quarter of 2015.began construction on its natural gas fueled combined cycle generation facility.
Customer Settlement2016 DTE Electric Depreciation Case Filing
In July 2014, an industrial customer of DTE Electric filed a complaintdepreciation case with the MPSC alleging they had been overchargedon November 1, 2016 requesting an increase in depreciation rates for the periodplant in service balances as of February 2008 through March 2014, and sought payment from DTE Electric of $22 million, plus interest. In July 2015, theDecember 31, 2015. The MPSC issued an order that found the customer is entitled to a refund in the amount of $20 million, plus interest calculated at 7% per annum. In July 2015,on December 6, 2018 authorizing DTE Electric issuedto increase its depreciation rates from 3.06% to 3.72%. The new rates will be effective upon a customer refund of $25 million, inclusive of interest. Approximately $16 million of the refund obligation isfinal order in DTE Electric's 2018 rate case filing expected to be recovered through the PSCR and other regulatory mechanisms. DTE Electric does not expect this order to have a material impact to its Consolidated Statements of Operations.by May 2019.
2015 DTE2017 Gas Rate Case Filing
DTE Gas filed a rate case with the MPSC on December 18, 2015November 22, 2017 requesting an increase in base rates of $183$85.1 million based on a projected twelve-month period ending October 31, 2017.September 30, 2019. The requested increase in base rates iswas primarily due primarily to an increase in net plant of $800 million, inclusive of IRM capital investments being recovered through approved IRM surcharge filings.plant. The rate filing also includes projected changes in sales, operation and maintenance expenses, and working capital. The rate filing also requestsrequested an increase in return on equity from 10.1% to 10.5% to 10.75% on a capital structure of 52% equity and 48% debt.included projected changes in sales, operations and maintenance expenses, and working capital. On May 24, 2018, DTE Gas anticipates self-implementing a ratereduced its initial requested increase in November 2016 with an MPSC order expected by December 2016. Concurrent withbase rates to $38.1 million, primarily due to the MPSC order in this rate case,effects of the existing IRM surcharge will be terminated. However, in this rate case filing, DTE Gas requested to implement a new IRM surcharge to become effective in January 2017.
DTE Gas IRM
In November 2014, DTE Gas filed an application withTCJA on the MPSC for approval of an increased IRM surcharge to recover an additional $47 million of annual capital expenditures in 2016 and 2017 for its gas main renewal program. In November 2015,original request. On September 13, 2018, the MPSC issued an order authorizingapproving an expansionannual revenue increase of its gas main renewal program and$9 million for services rendered on or after October 1, 2018. The MPSC authorized a return on equity of 10.0%. Refer to the 2017 Tax Reform section below for further detail regarding the impact of the TCJA Credit A filing for DTE Gas.
2017 Tax Reform
On December 27, 2017, the MPSC issued an increaseorder to consider changes in the IRM surchargerates of $16 million for 2016all Michigan rate-regulated utilities to reflect the effects of the federal TCJA. On January 19, 2018, DTE Electric and $31 million for 2017. The 2017 increase is subject to a reductionDTE Gas filed information with the MPSC regarding the potential change in revenue requirements due to the 2016 level ifTCJA effective January 1, 2018, and outlined their recommended method to flow the 2016 target is not met. The IRM surcharge authorized bycurrent and deferred tax benefits of those impacts to ratepayers.
On February 22, 2018, the MPSC issued an order in this case requiring utilities, including DTE Electric and DTE Gas, to follow a 3-step approach of credits and calculations. The first step is to establish Credit A, through contested cases. Credit A is a going-forward tax credit to reflect the reduction of the corporate tax rate from 35% to 21%. DTE Gas submitted its Credit A filing will becomeon March 28, 2018, reflecting a reduction in revenues of $38.2 million. The MPSC approved the $38.2 million reduction on May 30, 2018, effective July 1, 2018. With approval of the DTE Gas Rate Order on September 13, 2018, effective October 1, 2018, this separate Credit A was terminated. DTE Electric filed its Credit A application on May 18, 2018, reflecting a reduction in revenues of $157 million. On July 2016 and will be terminated upon24, 2018, the implementationMPSC issued an order approving a settlement in DTE Electric's Credit A filing reflecting a reduction in revenues of base rates requested in the December 18, 2015 rate case filing.$157 million. Rates reflecting this reduction were effective August 1, 2018.


85


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The second step is to establish Credit B, through contested cases. Credit B is a backward-looking tax credit to reflect the reduction of the corporate rate of 35% to 21%, for the period January 1, 2018 up to the date Credit A is implemented. The Credit B filing is required within sixty days after Credit A is implemented. For Credit B, DTE Electric and DTE Gas have been deferring the impact of the reduction to the corporate tax rate since January 1, 2018. DTE Gas submitted its Credit B filing on July 30, 2018, reflecting a $25 million refund effective January 2019 through June 2019. On October 24, 2018, the MPSC issued an order approving the refund in DTE Gas' Credit B filing. DTE Electric submitted its Credit B filing on September 21, 2018, reflecting a $93 million refund effective January 2019 through June 2019. On December 20, 2018, the MPSC issued an order approving the $93 million refund, inclusive of interest, in DTE Electric's Credit B filing, which commenced on January 1, 2019 through June 30, 2019.
The third step is to perform Calculation C to address all remaining issues relative to the new tax law, which is primarily the remeasurement of deferred taxes and how the amounts deferred as Regulatory liabilities will flow to ratepayers. DTE Gas filed its Calculation C case on November 16, 2018 to reduce the revenue requirement by $12 million related to the amortization of deferred tax remeasurement. DTE Electric addressed Calculation C in its general rate case filed July 6, 2018.

NOTE 910 — INCOME TAXES
Income Tax Summary
DTE Energy files a consolidated federal income tax return. DTE Electric is a part of the consolidated federal income tax return of DTE Energy. DTE Energy and its subsidiaries file consolidated and/or separate company income tax returns in various states and localities, including a consolidated return in the State of Michigan. DTE Electric is part of the Michigan consolidated income tax return of DTE Energy. The federal, state and local income tax expense for DTE Electric is determined on an individual company basis with no allocation of tax expenses or benefits from other affiliates of DTE Energy. DTE Electric had an income tax receivable fromreceivables with DTE Energy of $6$8 million and $29$12 million at December 31, 20152018 and 2014,2017, respectively.
The Registrants' total Income Tax Expense varied from the statutory federal income tax rate for the following reasons:
2015 2014 20132018 2017 2016
DTE Energy(In millions)(In millions)
Income Before Income Taxes$950
 $1,275
 $922
$1,216
 $1,287
 $1,105
Income tax expense at 35% statutory rate$333
 $446
 $323
Income tax expense at statutory rate - 21% in 2018 - 35% in 2017 and 2016$255
 $450
 $387
Production tax credits(122) (119) (68)(223) (189) (145)
Investment tax credits(7) (6) (6)(4) (4) (5)
Depreciation(4) (4) (4)2
 (4) (4)
AFUDC - Equity(8) (7) (5)
Noncontrolling interests2
 8
 12
AFUDC equity(14) (18) (10)
Employee Stock Ownership Plan dividends(5) (4) (4)(3) (5) (5)
Domestic production activities deduction
 
 (14)
Stock based compensation(3) (14) 
Subsidiary stock loss
 
 (10)
State and local income taxes, net of federal benefit35
 51
 37
60
 51
 58
Enactment of New York Corporate Income Tax Legislation, net of federal benefit
 8
 
Enactment of the Tax Cuts and Jobs Act21
 (105) 
Other, net8
 (1) (5)5
 5
 (7)
Income Tax Expense$230
 $364
 $254
$98
 $175
 $271
Effective income tax rate24.2% 28.5% 27.5%8.1% 13.6% 24.5%
 2015 2014 2013
DTE Electric(In millions)
Income Before Income Taxes$836
 $830
 $741
Income tax expense at 35% statutory rate$293
 $291
 $260
Production tax credits(31) (22) (15)
Investment tax credits(5) (5) (5)
Depreciation3
 3
 3
AFUDC - Equity(7) (7) (5)
Employee Stock Ownership Plan dividends(3) (3) (2)
Domestic production activities deduction
 (2) (18)
State and local income taxes, net of federal benefit43
 43
 41
Other, net(1) 
 (5)
Income Tax Expense$292
 $298
 $254
Effective income tax rate34.9% 35.9% 34.3%

86


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

 2018 2017 2016
DTE Electric(In millions)
Income Before Income Taxes$857
 $928
 $975
Income tax expense at statutory rate - 21% in 2018 - 35% in 2017 and 2016$180
 $325
 $341
Production tax credits(35) (36) (30)
Investment tax credits(3) (4) (4)
Depreciation2
 3
 3
AFUDC equity(3) (5) (6)
Employee Stock Ownership Plan dividends(2) (3) (3)
State and local income taxes, net of federal benefit49
 48
 56
Enactment of the Tax Cuts and Jobs Act7
 
 
Other, net(2) (1) (4)
Income Tax Expense$193
 $327
 $353
Effective income tax rate22.5% 35.2% 36.2%
Components of the Registrants' Income Tax Expense were as follows:
2015 2014 20132018 2017 2016
DTE Energy(In millions)(In millions)
Current income tax expense (benefit)          
Federal$(3) $(16) $74
$(17) $(22) $(1)
State and other income tax(4) 24
 16
1
 1
 7
Total current income taxes(7) 8
 90
(16) (21) 6
Deferred income tax expense          
Federal178
 289
 122
38
 118
 184
State and other income tax59
 67
 42
76
 78
 81
Total deferred income taxes237
 356
 164
114
 196
 265
Total$230
 $364
 $254

$98
 $175
 $271
2015 2014 20132018 2017 2016
DTE Electric(In millions)(In millions)
Current income tax expense (benefit)          
Federal$(26) $(19) $123
$
 $(17) $
State and other income tax(2) 20
 23
4
 (1) 11
Total current income taxes(28) 1
 146
4
 (18) 11
Deferred income tax expense          
Federal252
 251
 68
131
 270
 268
State and other income tax68
 46
 40
58
 75
 74
Total deferred income taxes320
 297
 108
189
 345
 342
Total$292
 $298
 $254

$193
 $327
 $353
Deferred tax assets and liabilities are recognized for the estimated future tax effect of temporary differences between the tax basis of assets or liabilities and the reported amounts in the Registrant's Consolidated Financial Statements. Consistent with rate making treatment,the original establishment of these deferred taxes are offsettax liabilities (assets), no recognition of these non-cash transactions have been reflected in the tables below for temporary differences which have related Regulatory assets and liabilities.
The Registrants' deferred tax assets (liabilities) were comprisedConsolidated Statements of the following at December 31:Cash Flows.
 DTE Energy DTE Electric
 2015 2014 2015 2014
 (In millions)
Property, plant, and equipment$(4,211) $(3,832) $(3,468) $(3,152)
Securitized regulatory assets5
 (2) 5
 (3)
Tax credit carry-forwards465
 296
 53
 
Pension and benefits(301) (152) (193) (43)
Federal net operating loss carry-forward177
 
 142
 
State and local net operating loss carry-forwards63
 39
 16
 
Investments in equity method investees(82) (84) 
 
Other(4) 65
 (53) 12
 (3,888) (3,670) (3,498) (3,186)
Less valuation allowance(35) (31) 
 
Long-term deferred income tax liabilities$(3,923) $(3,701) $(3,498) $(3,186)
        
Deferred income tax assets$1,088
 $861
 $453
 $357
Deferred income tax liabilities(5,011) (4,562) (3,951) (3,543)
 $(3,923) $(3,701) $(3,498) $(3,186)

87


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The Registrants' deferred tax assets (liabilities) were comprised of the following at December 31:
 DTE Energy DTE Electric
 2018 2017 2018 2017
 (In millions)
Property, plant, and equipment$(3,462) $(3,276) $(2,840) $(2,698)
Regulatory assets and liabilities(54) (94) (3) (31)
Tax credit carry-forwards1,178
 947
 250
 193
Pension and benefits311
 334
 258
 302
Federal net operating loss carry-forward117
 83
 2
 47
State and local net operating loss carry-forwards59
 70
 1
 5
Investments in equity method investees(216) (82) (1) 
Other125
 170
 87
 94
 (1,942) (1,848) (2,246) (2,088)
Less valuation allowance(33) (40) 
 
Long-term deferred income tax liabilities$(1,975) $(1,888) $(2,246) $(2,088)
        
Deferred income tax assets$2,021
 $1,814
 $855
 $830
Deferred income tax liabilities(3,996) (3,702) (3,101) (2,918)
 $(1,975) $(1,888) $(2,246) $(2,088)
Tax credit carry forwardscarry-forwards for DTE Energy include $181$871 million of general business credits that expire from 2034 through 20352038 and $284$307 million of alternative minimum tax credits that maywill be carried forward indefinitely.refundable over the next four years. The alternative minimum tax credits are production tax credits earned prior to 2006 but not utilized. The majority of these alternative minimum tax credits were generated from projects that had received a private letter ruling (PLR) from the IRS. These PLRs provide assurance as to the appropriateness of using these credits to offset taxable income, however, these tax credits are subject to IRS audit and adjustment. No valuation allowance is required for the tax credits carry-forward deferred tax asset.
DTE Energy has a federal net operating loss carry-forward available for use on the tax return of $517$555 million as of December 31, 2018. The net operating loss carry-forwards generated in 2015 which includes approximately $9 million related to windfall tax benefits attributable to stock-based compensation for which a benefitand 2016 will be recorded in additional paid-in capital ifexpire from 2035 through 2036, and when realized. The federalthe net operating loss carry-forward expiresgenerated in 2035.2018 will be carried forward indefinitely. No valuation allowance is required for the federal net operating loss deferred tax asset.
The above tables exclude unamortized investment tax credits that are shown separately on the Registrants' Consolidated Statements of Financial Position. Investment tax credits are deferred and amortized to income over the average life of the related property.
DTE Energy has state and local deferred tax assets related to net operating loss carry-forwards of $63$59 million and $39$70 million at December 31, 20152018 and 2014,2017, respectively. The state and local net operating loss carry-forwards expire from 20162019 through 2035.2038. DTE Energy has recorded valuation allowances at December 31, 20152018 and 20142017 of approximately $35$33 million and $31$40 million, respectively, with respect to these deferred tax assets. In assessing the realizability of deferred tax assets, DTE Energy considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible.
Tax credit carry-forwards for DTE Electric include $250 million of general business credits that expire from 2035 through 2038. No valuation allowance is required for the tax credits carry-forward deferred tax asset.
DTE Electric has a federal net operating loss carry-forward of $11 million as of December 31, 2018, which will expire in 2035. No valuation allowance is required for the federal net operating loss deferred tax asset.
DTE Electric has state and local deferred tax assets related to net operating loss carry-forwards of $16$1 million at December 31, 2015,2018, while there was no$5 million state and local deferred tax asset related to net operating loss carry-forwards at December 31, 2014.2017. No valuation allowance is required for DTE Electric's state and local net operating loss carry-forwards.
The above tables exclude unamortized investment tax credits that are shown separately on the Registrants' Consolidated Statements of Financial Position. Investment tax credits are deferred and amortized to income over the average life of the related property.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Tax Cuts and Jobs Act
On December 22, 2017, the TCJA was enacted reducing the corporate income tax rate from 35% to 21%, effective January 1, 2018. As a result of the enactment, the deferred tax assets and liabilities were remeasured to reflect the impact of the TCJA on the cumulative temporary differences expected to reverse after the effective date. The net impact of this remeasurement was a decrease in deferred tax liabilities of $2.56 billion, of which $2.45 billion was attributable to regulated utilities and offset to regulatory assets and liabilities. This regulatory treatment is consistent with prior precedent set by the MPSC from previous tax law changes. The remaining $105 million was attributable to the non-utility entities and was recognized as a net reduction to income tax expense in 2017.
On December 22, 2017, the SEC issued guidance under Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118), directing taxpayers to consider the implications of the TCJA as provisional when it does not have the necessary information available, prepared, or analyzed in reasonable detail to complete its accounting for the change in the tax law.  Refer to Note 3 to the Consolidated Financial Statements, "New Accounting Pronouncements," for a description of true-up adjustments to the remeasurement of deferred taxes recorded in 2018.
Uncertain Tax Positions
A reconciliation of the beginning and ending amount of unrecognized tax benefits for the Registrants is as follows:
2015 2014 20132018 2017 2016
DTE Energy(In millions)(In millions)
Balance at January 1$9
 $10
 $11
$10
 $10
 $3
Lapse of statute of limitations(6) (1) (1)
Additions for tax positions of prior years
 
 7
Balance at December 31$3
 $9
 $10
$10
 $10
 $10
2015 2014 20132018 2017 2016
DTE Electric(In millions)(In millions)
Balance at January 1$4
 $4
 $4
$13
 $13
 $4
Additions for tax positions of prior years
 
 9
Balance at December 31$4
 $4
 $4
$13
 $13
 $13
DTE Energy had $2$8 million of unrecognized tax benefits at December 31, 20152018 and 2014,2017 that, if recognized, would favorably impact its effective tax rate. DTE Energy does not anticipate any material decrease in unrecognized tax benefits in the next twelve months.
DTE Electric had $3 million and $2$10 million of unrecognized tax benefits at December 31, 20152018 and 2014, respectively,2017 that, if recognized, would favorably impact its effective tax rate. DTE Electric does not anticipate any material decrease in unrecognized tax benefits in the next twelve months.
The Registrants recognize interest and penalties pertaining to income taxes in Interest expense and Other expenses, respectively, on their Consolidated Statements of Operations.
Accrued interest pertaining to income taxes for both DTE Energy totaled $4 million and DTE Electric totaled $1$3 million at December 31, 20152018 and 2014. The Registrants had no accrued penalties pertaining to income taxes. The Registrants2017, respectively. DTE Energy recognized interest expense (income) related to income taxes of $1 million in 2018, a nominal amount in 2015, 2014,2017, and 2013.

88


$2 million in 2016. DTE Energy Company —had accrued no penalties pertaining to income taxes.
Accrued interest pertaining to income taxes for DTE Electric Company
Combined Notestotaled $5 million and $4 million at December 31, 2018 and 2017, respectively. DTE Electric recognized interest expense related to Consolidated Financial Statements — (Continued)income taxes of $1 million in 2018, a nominal amount in 2017, and $3 million in 2016. DTE Electric had accrued no penalties pertaining to income taxes.

In 2015,2018, DTE Energy, including DTE Electric, settled a federal tax audit for the 20132016 tax year. DTE Energy's federal income tax returns for 20142017 and subsequent years remain subject to examination by the IRS. DTE Energy's MBTMichigan Business Tax and MCITMichigan Corporate Income Tax returns for the year 2008 and subsequent years remain subject to examination by the State of Michigan. DTE Energy also files tax returns in numerous state and local jurisdictions with varying statutes of limitation.


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

NOTE 1011 — EARNINGS PER SHARE
DTE Energy reports both basic and diluted earnings per share. The calculation of dilutedBasic earnings per share assumesis calculated by dividing the issuancenet income, adjusted for income allocated to participating securities, by the weighted average number of potentially dilutive common shares outstanding during the period fromperiod. Diluted earnings per share reflect the exercise ofdilution that would occur if any potentially dilutive instruments were exercised or converted into common shares. DTE Energy's participating securities are restricted shares under the stock options. Aincentive program that contain rights to receive non-forfeitable dividends. Equity units, performance shares, and stock options do not receive cash dividends; as such, these awards are not considered participating securities. For additional information, see Notes 14 and 21 to Consolidated Financial Statements, "Long-Term Debt" and "Stock-Based Compensation," respectively.
The following is a reconciliation of both calculations is presented inDTE Energy's basic and diluted income per share calculation for the following table as ofyears ended December 31:
 2015 2014 2013
 (In millions, expect per share amounts)
Basic Earnings per Share     
Net Income Attributable to DTE Energy Company$727
 $905
 $661
Average number of common shares outstanding179
 177
 175
Weighted average net restricted shares outstanding
 
 1
Dividends declared — common shares$508
 $475
 $453
Dividends declared — net restricted shares2
 1
 1
Total distributed earnings$510
 $476
 $454
Net Income less distributed earnings$217
 $429
 $207
Distributed (dividends per common share)$2.84
 $2.69
 $2.59
Undistributed1.21
 2.42
 1.17
Total Basic Earnings per Common Share$4.05
 $5.11
 $3.76
      
Diluted Earnings per Share     
Net Income Attributable to DTE Energy Company$727
 $905
 $661
Average number of common shares outstanding179
 177
 175
Weighted average net restricted shares outstanding
 
 1
Dividends declared — common shares$508
 $475
 $453
Dividends declared — net restricted shares2
 1
 1
Total distributed earnings$510
 $476
 $454
Net Income less distributed earnings$217
 $429
 $207
Distributed (dividends per common share)$2.84
 $2.69
 $2.59
Undistributed1.21
 2.41
 1.17
Total Diluted Earnings per Common Share$4.05
 $5.10
 $3.76
 2018 2017 2016
 (In millions, except per share amounts)
Basic Earnings per Share     
Net Income Attributable to DTE Energy Company$1,120
 $1,134
 $868
Less: Allocation of earnings to net restricted stock awards(2) (2) (2)
Net income available to common shareholders — basic$1,118
 $1,132
 $866
      
Average number of common shares outstanding — basic181
 179
 179
Basic Earnings per Common Share$6.18
 $6.32
 $4.84
      
Diluted Earnings per Share     
Net Income Attributable to DTE Energy Company$1,120
 $1,134
 $868
Less: Allocation of earnings to net restricted stock awards(2) (2) (2)
Net income available to common shareholders — diluted$1,118
 $1,132
 $866
      
Average number of common shares outstanding — diluted181
 179
 179
Diluted Earnings per Common Share(a)
$6.17
 $6.32
 $4.83

(a)The 2016 Equity Units excluded from the calculation of diluted EPS were approximately 6.3 million for the years ended December 31, 2018 and 2017 as the dilutive stock price threshold was not met. For more information, see Note 14 to the Consolidated Financial Statements, "Long-Term Debt."

NOTE 1112 — FAIR VALUE
Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in a principal or most advantageous market. Fair value is a market-based measurement that is determined based on inputs, which refer broadly to assumptions that market participants use in pricing assets or liabilities. These inputs can be readily observable, market corroborated, or generally unobservable inputs. The Registrants make certain assumptions they believe that market participants would use in pricing assets or liabilities, including assumptions about risk, and the risks inherent in the inputs to valuation techniques. Credit risk of the Registrants and their counterparties is incorporated in the valuation of assets and liabilities through the use of credit reserves, the impact of which was immaterial at December 31, 20152018 and 2014.2017. The Registrants believe they use valuation techniques that maximize the use of observable market-based inputs and minimize the use of unobservable inputs.

89


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value in three broad levels. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. All assets and liabilities are required to be classified in their entirety based on the lowest level of input that is significant to the fair value measurement in its entirety. Assessing the significance of a particular input may require judgment considering factors specific to the asset or liability, and may affect the valuation of the asset or liability and its placement within the fair value hierarchy. The Registrants classify fair value balances based on the fair value hierarchy defined as follows:
Level 1 — Consists of unadjusted quoted prices in active markets for identical assets or liabilities that the Registrants have the ability to access as of the reporting date.
Level 2 — Consists of inputs other than quoted prices included within Level 1 that are directly observable for the asset or liability or indirectly observable through corroboration with observable market data.
Level 3 — Consists of unobservable inputs for assets or liabilities whose fair value is estimated based on internally developed models or methodologies using inputs that are generally less readily observable and supported by little, if any, market activity at the measurement date. Unobservable inputs are developed based on the best available information and subject to cost-benefit constraints.

90


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following table presents assets and liabilities for DTE Energy measured and recorded at fair value on a recurring basis as of December 31, 2015 and 2014:(a):
December 31, 2015 December 31, 2014December 31, 2018 December 31, 2017
Level 1 Level 2 Level 3 Netting (a) Net Balance Level 1 Level 2 Level 3 Netting (a) Net BalanceLevel 1 Level 2 Level 3 
Other(b)
 
Netting(c)
 Net Balance Level 1 Level 2 Level 3 
Other(b)
 
Netting(c)
 Net Balance
(In millions)(In millions)
Assets:                   
Assets                       
Cash equivalents (b)(d)$13
 $3
 $
 $
 $16
 $13
 $99
 $
 $
 $112
$16
 $2
 $
 $
 $
 $18
 $16
 $3
 $
 $
 $
 $19
Nuclear decommissioning trusts759
 477
 
 
 1,236
 792
 449
 
 
 1,241
                       
Other investments (c)149
 
 
 
 149
 100
 50
 
 
 150
Equity securities851
 
 
 
 
 851
 978
 
 
 
 
 978
Fixed income securities12
 490
 
 
 
 502
 18
 477
 
 
 
 495
Private equity and other
 
 
 20
 
 20
 
 
 
 5
 
 5
Cash equivalents5
 
 
 
 
 5
 14
 
 
 
 
 14
Other investments(e)
          

           

Equity securities110
 
 
 
 
 110
 118
 
 
 
 
 118
Fixed income securities69
 
 
 
 
 69
 72
 
 
 
 
 72
Cash equivalents4
 
 
 
 
 4
 4
 
 
 
 
 4
Derivative assets: 
  
  
  
    
  
  
  
                         
Commodity Contracts: 
  
  
  
    
  
  
  
                         
Natural Gas193
 91
 103
 (285) 102
 555
 140
 92
 (681) 106
199
 87
 63
 
 (277) 72
 148
 112
 97
 
 (256) 101
Electricity
 239
 68
 (232) 75
 
 295
 47
 (280) 62

 247
 56
 
 (252) 51
 
 243
 42
 
 (241) 44
Other2
 
 3
 (2) 3
 42
 
 3
 (42) 3

 
 7
 
 (1) 6
 
 
 9
 
 
 9
Other derivative contracts (d)
 12
 
 (9) 3
 
 4
 
 (3) 1
Foreign currency exchange contracts
 4
 
 
 
 4
 
 1
 
 
 (1) 
Total derivative assets195
 342
 174
 (528) 183
 597
 439
 142
 (1,006) 172
199
 338
 126
 
 (530) 133
 148
 356
 148
 
 (498) 154
Total$1,116
 $822
 $174
 $(528) $1,584
 $1,502
 $1,037
 $142
 $(1,006) $1,675
$1,266
 $830
 $126
 $20
 $(530) $1,712
 $1,368
 $836
 $148
 $5
 $(498) $1,859
                                          
Liabilities:                   
Liabilities                       
Derivative liabilities:                                          
Commodity Contracts: 
  
  
  
    
  
  
  
                         
Natural Gas$(218) $(57) $(108) $294
 $(89) $(578) $(78) $(62) $679
 $(39)$(197) $(71) $(112) $
 $272
 $(108) $(141) $(111) $(126) $
 $263
 $(115)
Electricity
 (243) (62) 253
 (52) 
 (290) (52) 298
 (44)
 (227) (58) 
 240
 (45) 
 (245) (30) 
 246
 (29)
Other(2) 
 (8) 8
 (2) (32) (9) (4) 45
 

 (1) 
 
 1
 
 
 
 (1) 
 1
 
Other derivative contracts (d)
 (7) 
 7
 
 
 (5) 
 3
 (2)
Interest rate contracts
 (3) 
 
 
 (3) 
 
 
 
 
 
Foreign currency exchange contracts
 
 
 
 
 
 
 (3) 
 
 1
 (2)
Total derivative liabilities(220) (307) (178) 562
 (143) (610) (382) (118) 1,025
 (85)(197) (302) (170) 
 513
 (156) (141) (359) (157) 
 511
 (146)
Total$(220) $(307) $(178) $562
 $(143) $(610) $(382) $(118) $1,025
 $(85)$(197) $(302) $(170) $
 $513
 $(156) $(141) $(359) $(157) $
 $511
 $(146)
Net Assets (Liabilities) at the end of the period$896
 $515
 $(4) $34
 $1,441
 $892
 $655
 $24
 $19
 $1,590
Assets:                   
Net Assets (Liabilities) at end of period$1,069
 $528
 $(44) $20
 $(17) $1,556
 $1,227
 $477
 $(9) $5
 $13
 $1,713
Assets                       
Current$174
 $284
 $128
 $(441) $145
 $582
 $504
 $109
 $(955) $240
$212
 $273
 $96
 $
 $(461) $120
 $157
 $298
 $104
 $
 $(437) $122
Noncurrent (e)942
 538
 46
 (87) 1,439
 920
 533
 33
 (51) 1,435
Noncurrent1,054
 557
 30
 20
 (69) 1,592
 1,211
 538
 44
 5
 (61) 1,737
Total Assets$1,116
 $822
 $174
 $(528) $1,584
 $1,502
 $1,037
 $142
 $(1,006) $1,675
$1,266
 $830
 $126
 $20
 $(530) $1,712
 $1,368
 $836
 $148
 $5
 $(498) $1,859
Liabilities:                   
Liabilities                       
Current$(174) $(260) $(87) $464
 $(57) $(572) $(357) $(112) $964
 $(77)$(191) $(251) $(76) $
 $451
 $(67) $(137) $(313) $(108) $
 $459
 $(99)
Noncurrent(46) (47) (91) 98
 (86) (38) (25) (6) 61
 (8)(6) (51) (94) 
 62
 (89) (4) (46) (49) 
 52
 (47)
Total Liabilities$(220) $(307) $(178) $562
 $(143) $(610) $(382) $(118) $1,025
 $(85)$(197) $(302) $(170) $
 $513
 $(156) $(141) $(359) $(157) $
 $511
 $(146)
Net Assets (Liabilities) at the end of the period$896
 $515
 $(4) $34
 $1,441
 $892
 $655
 $24
 $19
 $1,590
Net Assets (Liabilities) at end of period$1,069
 $528
 $(44) $20
 $(17) $1,556
 $1,227
 $477
 $(9) $5
 $13
 $1,713

(a)See footnotes on following page.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

(b)Amounts represent assets valued at NAV as a practical expedient for fair value.
(c)Amounts represent the impact of master netting agreements that allow DTE Energy to net gain and loss positions and cash collateral held or placed with the same counterparties.
(b)(d)At December 31, 2015, available-for-sale securities2018, the $18 million consisted of $16$3 million, included $8$5 million, and $8$10 million of cash equivalents included in Cash and Cash equivalents, Restricted cash, and Other investments on DTE Energy's Consolidated Statements of Financial Position, respectively. At December 31, 2014, available-for-sale securities2017, the $19 million consisted of $112 million, included $105$8 million and $7$11 million of cash equivalents included in Restricted cash and Other investments on DTE Energy's Consolidated Statements of Financial Position, respectively.
(c)(e)Excludes cash surrender value of life insurance investments.
(d)Primarily includes foreign currency exchange contracts.
(e)Includes $149 million and $150 million at December 31, 2015 and 2014, respectively, of other investments that are included in DTE Energy's Consolidated Statements of Financial Position in Other investments.

91


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following table presents assets for DTE Electric measured and recorded at fair value on a recurring basis as of December 31, 2015 and 2014:basis:
December 31, 2015 December 31, 2014December 31, 2018 December 31, 2017
Level 1 Level 2 Level 3 Net Balance Level 1 Level 2 Level 3 Net BalanceLevel 1 Level 2 Level 3 
Other(a)
 Net Balance Level 1 Level 2 Level 3 OtherNet Balance
(In millions)(In millions)
Assets:               
Assets                 
Cash equivalents (a)(b)$5
 $3
 $
 $8
 $5
 $99
 $
 $104
$8
 $2
 $
 $
 $10
 $8
 $3
 $
 $
$11
Nuclear decommissioning trusts759
 477
 
 1,236
 792
 449
 
 1,241
                 
Equity securities851
 
 
 
 851
 978
 
 
 
978
Fixed income securities12
 490
 
 
 502
 18
 477
 
 
495
Private equity and other
 
 
 20
 20
 
 
 
 5
5
Cash equivalents5
 
 
 
 5
 14
 
 
 
14
Other investments8
 
 
 8
 97
 50
 
 147
                 
Equity securities10
 
 
 
 10
 11
 
 
 
11
Derivative assets — FTRs
 
 3
 3
 
 
 3
 3

 
 6
 
 6
 
 
 9
 
9
Total$772
 $480
 $3
 $1,255
 $894
 $598
 $3
 $1,495
$886
 $492
 $6
 $20
 $1,404
 $1,029
 $480
 $9
 $5
$1,523
                                
Assets:               
Assets                 
Current$5
 $3
 $3
 $11
 $5
 $99
 $3
 $107
$8
 $2
 $6
 $
 $16
 $8
 $3
 $9
 $
$20
Noncurrent767
 477
 
 1,244
 889
 499
 
 1,388
878
 490
 
 20
 1,388
 1,021
 477
 
 5
1,503
Total Assets$772
 $480
 $3
 $1,255
 $894
 $598
 $3
 $1,495
$886
 $492
 $6
 $20
 $1,404
 $1,029
 $480
 $9
 $5
$1,523

(a)Amounts represent assets valued at NAV as a practical expedient for fair value.
(b)At December 31, 2015, available-for-sale securities of $82018, the $10 million consisted of cash equivalents included in Other investments on DTE Electric's Consolidated Statements of Financial Position. At December 31, 2014, available-for-sale securities of $1042017, the $11 million included $96 million and $8 millionconsisted of cash equivalents included in Restricted cash and Other investments respectively, on DTE Electric's Consolidated Statements of Financial Position.
Cash Equivalents
Cash equivalents include investments with maturities of three months or less when purchased. The cash equivalents shown in the fair value table are comprised of short-term investments and money market funds.
Nuclear Decommissioning Trusts and Other Investments
The nuclear decommissioning trusts and other investments hold debt and equity securities directly and indirectly through institutional mutualcommingled funds. Other assets such as private equity investments are used to enhance long-term returns while improving portfolio diversification. All pricing for private equity investments in this category are classified as NAV assets. Exchange-traded debt and equity securities held directly are valued using quoted market prices in actively traded markets. The institutional mutual funds hold exchange-traded equity or debt securities and are valued based on stated NAVs. Non-exchange-tradedNon-exchange traded fixed income securities are valued based upon quotations available from brokers or pricing services. Commingled funds that hold exchange-traded equity or debt securities (exchange and non-exchange traded) and are valued based on publicly available NAVs. A primary price source is identified by asset type, class, or issue for each security. The trustee monitors prices supplied by pricing services and may use a supplemental price source or change the primary price source of a given security if the trustee determines that another price source is considered to be preferable. The Registrants have obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Additionally, the Registrants selectively corroborate the fair value of securities by comparison of market-based price sources. Investment policies and procedures are determined by DTE Energy's Trust Investments Department which reports to DTE Energy's Vice President and Treasurer.

92


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Derivative Assets and Liabilities
Derivative assets and liabilities are comprised of physical and financial derivative contracts, including futures, forwards, options, and swaps that are both exchange-traded and over-the-counter traded contracts. Various inputs are used to value derivatives depending on the type of contract and availability of market data. Exchange-traded derivative contracts are valued using quoted prices in active markets. The Registrants consider the following criteria in determining whether a market is considered active: frequency in which pricing information is updated, variability in pricing between sources or over time, and the availability of public information. Other derivative contracts are valued based upon a variety of inputs including commodity market prices, broker quotes, interest rates, credit ratings, default rates, market-based seasonality, and basis differential factors. The Registrants monitor the prices that are supplied by brokers and pricing services and may use a supplemental price source or change the primary price source of an index if prices become unavailable or another price source is determined to be more representative of fair value. The Registrants have obtained an understanding of how these prices are derived. Additionally, the Registrants selectively corroborate the fair value of their transactions by comparison of market-based price sources. Mathematical valuation models are used for derivatives for which external market data is not readily observable, such as contracts which extend beyond the actively traded reporting period. The Registrants have established a Risk Management Committee whose responsibilities include directly or indirectly ensuring all valuation methods are applied in accordance with predefined policies. The development and maintenance of the Registrants' forward price curves has been assigned to DTE Energy's Risk Management Department, which is separate and distinct from the trading functions within DTE Energy.
The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for DTE Energy for the years ended December 31, 2015 and 2014:Energy:
Year Ended December 31, 2015 Year Ended December 31, 2014Year Ended December 31, 2018 Year Ended December 31, 2017
Natural Gas Electricity Other Total Natural Gas Electricity Other TotalNatural Gas Electricity Other Total Natural Gas Electricity Other Total
(In millions)(In millions)
Net Assets (Liabilities) as of December 31$30
 $(5) $(1) $24
 $(52) $13
 $3
 $(36)
Net Assets (Liabilities) as of January 1$(29) $12
 $8
 $(9) $(96) $9
 $(1) $(88)
Transfers into Level 3 from Level 2
 
 
 
 
 
 
 

 
 
 
 
 
 
 
Transfers from Level 3 into Level 2
 
 
 
 (2) 
 
 (2)(3) 
 
 (3) 
 
 
 
Total gains (losses):               
Total gains (losses)               
Included in earnings(44) 44
 (8) (8) (40) 25
 (5) (20)(146) 29
 1
 (116) (29) 109
 2
 82
Recorded in Regulatory assets/liabilities
 
 12
 12
 
 
 8
 8
Recorded in Regulatory liabilities
 
 9
 9
 
 
 25
 25
Purchases, issuances, and settlements:                              
Purchases
 2
 
 2
 
 1
 
 1

 
 
 
 
 
 
 
Issuances
 
 
 
 
 (3) 
 (3)
 
 
 
 
 
 
 
Settlements9
 (35) (8) (34) 124
 (41) (7) 76
129
 (43) (11) 75
 96
 (106) (18) (28)
Net Assets (Liabilities) as of December 31$(5) $6
 $(5) $(4) $30
 $(5) $(1) $24
$(49) $(2) $7
 $(44) $(29) $12
 $8
 $(9)
The amount of total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2015 and 2014 and reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, and gas — non-utility in DTE Energy's Consolidated Statements of Operations$(135) $13
 $(7) $(129) $35
 $9
 $(4) $40
The amount of total gains (losses) included in Net Income attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2018 and 2017 and reflected in Operating Revenues — Non-utility operations and Fuel, purchased power, and gas — non-utility in DTE Energy's Consolidated Statements of Operations$(119) $15
 $(16) $(120) $(30) $50
 $1
 $21

93


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following table presents the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis for DTE Electric for the years ended December 31, 2015 and 2014:Electric:
Year Ended December 31,Year Ended December 31,
2015 20142018 2017
(In millions)(In millions)
Net Assets as of December 31$3
 $3
Change in fair value recorded in Regulatory assets/liabilities12
 8
Net Assets as of January 1$9
 $2
Change in fair value recorded in Regulatory liabilities9
 25
Purchases, issuances, and settlements:      
Settlements(12) (8)(12) (18)
Net Assets as of December 31$3
 $3
$6
 $9
The amount of total gains (losses) included in Regulatory assets and liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2015 and 2014 and reflected in DTE Electric's Consolidated Statements of Financial Position$3
 $3
The amount of total gains (losses) included in Regulatory liabilities attributed to the change in unrealized gains (losses) related to assets and liabilities held at December 31, 2018 and 2017 and reflected in DTE Electric's Consolidated Statements of Financial Position$6
 $9
Derivatives are transferred between levels primarily due to changes in the source data used to construct price curves as a result of changes in market liquidity. Transfers in and transfers out are reflected as if they had occurred at the beginning of the period.
There were no transfers between Levels 1 and 2 for the Registrants during the years ended December 31, 20152018 and 2014,2017, and there were no transfers from or into Level 3 for DTE Electric during the same periods.
The following tables present the unobservable inputs related to DTE Energy's Level 3 assets and liabilities as of December 31, 2015 and 2014:liabilities:
 December 31, 2015       December 31, 2018      
Commodity Contracts Derivative Assets Derivative Liabilities Valuation Techniques Unobservable Input Range Weighted Average Derivative Assets Derivative Liabilities Valuation Techniques Unobservable Input Range Weighted Average
 (In millions)       (In millions)      
Natural Gas $103
 $(108) Discounted Cash Flow Forward basis price (per MMBtu) $(1.50) — $2.77/MMBtu $(0.19)/MMBtu $63
 $(112) Discounted Cash Flow Forward basis price (per MMBtu) $(2.15) $5.59/MMBtu $(0.1)/MMBtu
Electricity $68
 $(62) Discounted Cash Flow Forward basis price (per MWh) $(11) — $14/MWh $2/MWh $56
 $(58) Discounted Cash Flow Forward basis price (per MWh) $(7) $9/MWh $1/MWh
 December 31, 2014       December 31, 2017      
Commodity Contracts Derivative Assets Derivative Liabilities Valuation Techniques Unobservable Input Range Weighted Average Derivative Assets Derivative Liabilities Valuation Techniques Unobservable Input Range Weighted Average
 (In millions)       (In millions)      
Natural Gas $92
 $(62) Discounted Cash Flow Forward basis price (per MMBtu) $(2.28) — $7.83/MMBtu $(0.22)/MMBtu $97
 $(126) Discounted Cash Flow Forward basis price (per MMBtu) $(1.10) $9.75/MMBtu $(0.03)/MMBtu
Electricity $47
 $(52) Discounted Cash Flow Forward basis price (per MWh) $(14) — $15/MWh $4/MWh $42
 $(30) Discounted Cash Flow Forward basis price (per MWh) $(5) $15/MWh $2/MWh
The unobservable inputs used in the fair value measurement of the electricity and natural gas commodity types consist of inputs that are less observable due in part to lack of available broker quotes, supported by little, if any, market activity at the measurement date or are based on internally developed models. Certain basis prices (i.e., the difference in pricing between two locations) included in the valuation of natural gas and electricity contracts were deemed unobservable.
The inputs listed above would have a direct impact on the fair values of the above security types if they were adjusted. A significant increase (decrease) in the basis price would result in a higher (lower) fair value for long positions, with offsetting impacts to short positions.

94


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Fair Value of Financial Instruments
The fair value of financial instruments included in the table below is determined by using quoted market prices when available. When quoted prices are not available, pricing services may be used to determine the fair value with reference to observable interest rate indexes. The Registrants have obtained an understanding of how the fair values are derived. The Registrants also selectively corroborate the fair value of their transactions by comparison of market-based price sources. Discounted cash flow analyses based upon estimated current borrowing rates are also used to determine fair value when quoted market prices are not available. The fair values of notes receivable, excluding capital leases, are generally estimated using discounted cash flow techniques that incorporate market interest rates as well as assumptions about the remaining life of the loans and credit risk. Depending on the information available, other valuation techniques may be used that rely on internal assumptions and models. Valuation policies and procedures for the Registrants are determined by DTE Energy's Treasury Department which reports to DTE Energy's Vice President and Treasurer.
The following table presents the carrying amount and fair value of financial instruments for DTE Energy as of December 31, 2015 and 2014:Energy:
December 31, 2015 December 31, 2014December 31, 2018 December 31, 2017
Carrying Fair Value Carrying Fair ValueCarrying Fair Value Carrying Fair Value
Amount Level 1 Level 2 Level 3 Amount Level 1 Level 2 Level 3Amount Level 1 Level 2 Level 3 Amount Level 1 Level 2 Level 3
(In millions)(In millions)
Notes receivable, excluding capital leases$32
 $
 $
 $32
 $41
 $
 $
 $41
Notes receivable(a), excluding capital leases
$40
 $
 $
 $40
 $38
 $
 $
 $38
Dividends payable$131
 $131
 $
 $
 $122
 $122
 $
 $
$172
 $172
 $
 $
 $158
 $158
 $
 $
Short-term borrowings$499
 $
 $499
 $
 $398
 $
 $398
 $
$609
 $
 $609
 $
 $621
 $
 $621
 $
Long-term debt, excluding capital leases$9,285
 $496
 $8,136
 $1,203
 $8,606
 $489
 $8,308
 $706
Notes payable — Other(b), excluding capital leases
$41
 $
 $
 $41
 $12
 $
 $
 $12
Long-term debt(c)
$13,622
 $1,796
 $10,712
 $1,317
 $12,288
 $1,939
 $10,571
 $764

(a)Current portion included in Current Assets — Other on DTE Energy's Consolidated Statements of Financial Position.
(b)Included in Current Liabilities — Other and Other Liabilities — Other on DTE Energy's Consolidated Statements of Financial Position.
(c)Includes debt due within one year, unamortized debt discounts, and issuance costs. Excludes Capital lease obligations.
The following table presents the carrying amount and fair value of financial instruments for DTE Electric as of December 31, 2015 and 2014:Electric:
December 31, 2015 December 31, 2014December 31, 2018 December 31, 2017
Carrying Fair Value Carrying Fair ValueCarrying Fair Value Carrying Fair Value
Amount Level 1 Level 2 Level 3 Amount Level 1 Level 2 Level 3Amount Level 1 Level 2 Level 3 Amount Level 1 Level 2 Level 3
(In millions)(In millions)
Notes receivable, excluding capital leases$5
 $
 $
 $5
 $12
 $
 $
 $12
$6
 $
 $
 $6
 $
 $
 $
 $
Notes receivable — affiliates$
 $
 $
 $
 $8
 $
 $
 $8
Short-term borrowings — affiliates$75
 $
 $
 $75
 $84
 $
 $
 $84
$101
 $
 
 $101
 $116
 $
 $
 $116
Short-term borrowings — other$272
 $
 $272
 $
 50
 $
 $50
 $
$149
 $
 $149
 $
 238
 $
 $238
 $
Long-term debt, excluding capital leases$5,624
 $
 $5,432
 $545
 $5,259
 $
 $5,341
 $496
Notes payable — Other(a), excluding capital leases
$21
 $
 $
 $21
 $2
 $
 $
 $2
Long-term debt(b)
$6,538
 $
 $6,552
 $161
 $6,017
 $
 $6,441
 $171

(a)Included in Current Liabilities — Other and Other Liabilities — Other on DTE Electric's Consolidated Statements of Financial Position.
(b)Includes debt due within one year, unamortized debt discounts, and issuance costs. Excludes Capital lease obligations.
For further fair value information on financial and derivative instruments, see Note 1213 to the Consolidated Financial Statements, "Financial and Other Derivative Instruments".Instruments."
Nuclear Decommissioning Trust Funds
DTE Electric has a legal obligation to decommission its nuclear power plants following the expiration of its operating licenses. This obligation is reflected as an AROAsset retirement obligation on DTE Electric's Consolidated Statements of Financial Position. Rates approved by the MPSC provide for the recovery of decommissioning costs of Fermi 2 and the disposal of low-level radioactive waste. DTE Electric is continuing to fund FERC jurisdictional amounts for decommissioning even though explicit provisions are not included in FERC rates. See Note 78 to the Consolidated Financial Statements, "Asset Retirement Obligations".Obligations."

The following table summarizes DTE Electric's fair value of the nuclear decommissioning trust fund assets:
95

 December 31,
 2018 2017
 (In millions)
Fermi 2$1,372
 $1,475
Fermi 13
 3
Low-level radioactive waste3
 14

$1,378
 $1,492

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following table summarizes DTE Electric's fair value of the nuclear decommissioning trust fund assets:
 December 31, 2015 December 31, 2014
 (In millions)
Fermi 2$1,211
 $1,221
Fermi 13
 3
Low-level radioactive waste22
 17
Total$1,236
 $1,241
The costs of securities sold are determined on the basis of specific identification. The following table sets forth DTE Electric's gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds:
Year Ended December 31,Year Ended December 31,
2015 2014 20132018 2017 2016
(In millions)(In millions)
Realized gains$39
 $54
 $83
$65
 $83
 $74
Realized losses$(33) $(33) $(41)$(42) $(29) $(63)
Proceeds from sales of securities$885
 $1,146
 $1,118
Proceeds from sale of securities$1,203
 $1,240
 $1,457
Realized gains and losses from the sale of securities forand unrealized gains and losses incurred by the Fermi 2 and the low-level radioactive waste fundstrust are recorded to the Regulatory asset and Nuclear decommissioning liability. Realized gains and losses from the sale of securities and unrealized gains and losses on the low-level radioactive waste funds are recorded to the Nuclear decommissioning liability.
The following table sets forth DTE Electric's fair value and unrealized gains and losses for the nuclear decommissioning trust funds:
 December 31, 2015 December 31, 2014
 Fair
Value
 Unrealized
Gains
 Unrealized Losses Fair
Value
 Unrealized
Gains
 Unrealized Losses
 (In millions)
Equity securities$731
 $195
 $(68) $756
 $204
 $(39)
Debt securities499
 16
 (4) 474
 21
 (2)
Cash and cash equivalents6
 
 
 11
 
 
 $1,236
 $211

$(72) $1,241
 $225

$(41)
 December 31, 2018 December 31, 2017
 Fair
Value
 Unrealized
Gains
 Unrealized Losses Fair
Value
 Unrealized
Gains
 Unrealized Losses
 (In millions)
Equity securities$851
 $235
 $(79) $978
 $320
 $(32)
Fixed income securities502
 7
 (8) 495
 13
 (3)
Private equity and other20
 
 
 5
 
 
Cash equivalents5
 
 
 14
 
 
 $1,378
 $242

$(87) $1,492
 $333

$(35)
The debtfollowing table summarizes the fair value of the fixed income securities at December 31, 2015 and 2014 had an average maturity of approximately 6 years and 7 years, respectively. Securities held in the Nuclearnuclear decommissioning trust funds are classified as available-for-sale. As DTE Electric does not have the ability to hold impaired investments for a period of time sufficient to allow for the anticipated recovery of market value, all unrealized losses are considered to be other-than-temporary impairments.by contractual maturity:
Unrealized losses incurred by the Fermi 2 trust are recognized as a Regulatory asset.
 December 31, 2018
 (In millions)
Due within one year$29
Due after one through five years89
Due after five through ten years113
Due after ten years271
 $502
Other Securities
At December 31, 20152018 and 2014,2017, the Registrants' securities, included in Other investments on the Consolidated Statements of Financial Position, were comprised primarily of money market and equity securities. There were no unrealizedNet losses on available-for-sale securities which were reclassified out of Other comprehensive income (loss) and realized into Net Income for DTE Energy or DTE Electric during the years ended December 31, 2015 and 2014. Gains related to tradingequity securities held at December 31, 2015, 2014, and 20132018 were $1 million, $14$11 million and $22net gains related to equity securities held at December 31, 2017 and 2016 were $26 million, and $15 million, respectively, for DTE Energy, including $1 million, $12 million, and $19 million, respectively, relating to DTE Electric. The trading gainsthe Registrants. Gains or losses related to the Rabbi Trust assets are allocated from DTE Energy to DTE Electric.


96


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

NOTE 1213 — FINANCIAL AND OTHER DERIVATIVE INSTRUMENTS
The Registrants recognize all derivatives at their fair value as Derivative assets or liabilities on their respective Consolidated Statements of Financial Position unless they qualify for certain scope exceptions, including the normal purchases and normal sales exception. Further, derivatives that qualify and are designated for hedge accounting are classified as either hedges of a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (cash flow hedge); or as hedges of the fair value of a recognized asset or liability or of an unrecognized firm commitment (fair value hedge). For cash flow hedges, the portion of the derivative gain or loss that is effective in offsetting the change in the value of the underlying exposure is deferred in Accumulated other comprehensive income (loss) and later reclassified into earnings when the underlying transaction occurs. Gains or losses from the ineffective portion of cash flow hedges are recognized in earnings immediately. For fair value hedges, changes in fair values for the derivative and hedged item are recognized in earnings each period. For derivatives that do not qualify or are not designated for hedge accounting, changes in fair value are recognized in earnings each period.
The Registrants' primary market risk exposure is associated with commodity prices, credit, and interest rates. The Registrants have risk management policies to monitor and manage market risks. The Registrants use derivative instruments to manage some of the exposure. DTE Energy uses derivative instruments for trading purposes in its Energy Trading segment. Contracts classified as derivative instruments include electricity, natural gas, oil, certain coal forwards, futures, options, swaps, and foreign currency exchange contracts. Items not classified as derivatives include natural gas inventory, pipeline transportation contracts, renewable energy credits, and natural gas storage assets.
DTE Electric — DTE Electric generates, purchases, distributes, and sells electricity. DTE Electric uses forward energy contracts to manage changes in the price of electricity and fuel. Substantially all of these contracts meet the normal purchases and normal sales exception and are therefore accounted for under the accrual method. Other derivative contracts are MTM and recoverable through the PSCR mechanism when settled. This results in the deferral of unrealized gains and losses as Regulatory assets or liabilities until realized.
DTE Gas — DTE Gas purchases, stores, transports, distributes and sells natural gas, and sells storage and transportation capacity. DTE Gas has fixed-priced contracts for portions of its expected natural gas supply requirements through March 2018.2021. Substantially all of these contracts meet the normal purchases and normal sales exception and are therefore accounted for under the accrual method. DTE Gas may also sell forward transportation and storage capacity contracts. Forward transportation and storage contracts are generally not derivatives and are therefore accounted for under the accrual method.
Gas Storage and Pipelines — This segment is primarily engaged in services related to the gathering, transportation, and storage of natural gas. Primarily fixed-priced contracts are used in the marketing and management of transportation and storage services. Generally, these contracts are not derivatives and are therefore accounted for under the accrual method.
Power and Industrial Projects — This segment manages and operates energy and pulverized coal projects, a coke battery, reduced emissions fuel projects, landfillrenewable gas recovery, and power generation assets. Primarily fixed-price contracts are used in the marketing and management of the segment assets. These contracts are generally not derivatives and are therefore accounted for under the accrual method.
Energy Trading — Commodity Price Risk — Energy Trading markets and trades electricity, natural gas physical products, and energy financial instruments, and provides energy and asset management services utilizing energy commodity derivative instruments. Forwards, futures, options, and swap agreements are used to manage exposure to the risk of market price and volume fluctuations in its operations. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met.
Energy Trading — Foreign Currency Exchange Risk — Energy Trading has foreign currency exchange forward contracts to economically hedge fixed Canadian dollar commitments existing under natural gas and power purchase and sale contracts and natural gas transportation contracts. DTE Energy Trading enters into these contracts to mitigate price volatility with respect to fluctuations of the Canadian dollar relative to the U.S. dollar. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met.
Corporate and Other — Interest Rate Risk — DTE Energy may use interest rate swaps, treasury locks, and other derivatives to hedge the risk associated with interest rate market volatility.

97


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Credit Risk — DTE Energy maintains credit policies that significantly minimize overall credit risk. These policies include an evaluation of potential customers’ and counterparties’ financial condition, including the viability of underlying productive assets, credit rating, collateral requirements, or other credit enhancements such as letters of credit or guarantees. DTE Energy generally uses standardized agreements that allow the netting of positive and negative transactions associated with a single counterparty. DTE Energy maintains a provision for credit losses based on factors surrounding the credit risk of its customers, historical trends, and other information. Based on DTE Energy’sEnergy's credit policies and its December 31, 20152018 provision for credit losses, DTE Energy’s exposure to counterparty nonperformance is not expected to have a material adverse effect on DTE Energy's Consolidated Financial Statements.
Derivative Activities
DTE Energy manages its MTM risk on a portfolio basis based upon the delivery period of its contracts and the individual components of the risks within each contract. Accordingly, it records and manages the energy purchase and sale obligations under its contracts in separate components based on the commodity (e.g. electricity or natural gas), the product (e.g. electricity for delivery during peak or off-peak hours), the delivery location (e.g. by region), the risk profile (e.g. forward or option), and the delivery period (e.g. by month and year). The following describes the categories of activities represented by their operating characteristics and key risks:
Asset Optimization — Represents derivative activity associated with assets owned and contracted by DTE Energy, including forward natural gas purchases and sales, natural gas transportation, and storage capacity. Changes in the value of derivatives in this category typically economically offset changes in the value of underlying non-derivative positions, which do not qualify for fair value accounting. The difference in accounting treatment of derivatives in this category and the underlying non-derivative positions can result in significant earnings volatility.
Marketing and Origination — Represents derivative activity transacted by originating substantially hedged positions with wholesale energy marketers, producers, end-users, utilities, retail aggregators, and alternative energy suppliers.
Fundamentals Based Trading — Represents derivative activity transacted with the intent of taking a view, capturing market price changes, or putting capital at risk. This activity is speculative in nature as opposed to hedging an existing exposure.
Other — Includes derivative activity at DTE Electric related to FTRs. Changes in the value of derivative contracts at DTE Electric are recorded as Derivative assets or liabilities, with an offset to Regulatory assets or liabilities as the settlement value of these contracts will be included in the PSCR mechanism when realized.
The following table presents the fair value of derivative instruments as of December 31, 2015 and 2014 for DTE Energy:
 December 31, 2015 December 31, 2014
 Derivative
Assets
 Derivative
Liabilities
 Derivative
Assets
 Derivative
Liabilities
 (In millions)
Derivatives not designated as hedging instruments:       
Foreign currency exchange contracts$12
 $(7) $4
 $(5)
Commodity Contracts:     
  
Natural Gas387
 (383) 787
 (718)
Electricity307
 (305) 342
 (342)
Other5
 (10) 45
 (45)
Total derivatives not designated as hedging instruments:$711
 $(705) $1,178
 $(1,110)
        
Current$570
 $(521) $1,083
 $(1,041)
Noncurrent141
 (184) 95
 (69)
Total derivatives$711
 $(705) $1,178
 $(1,110)

98


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following table presents the fair value of derivative instruments asfor DTE Energy:
 December 31, 2018 December 31, 2017
 Derivative
Assets
 Derivative
Liabilities
 Derivative
Assets
 Derivative
Liabilities
 (In millions)
Derivatives designated as hedging instruments       
Interest rate contracts$
 $(3) $
 $
Derivatives not designated as hedging instruments       
Commodity contracts       
Natural gas$349
 $(380) $357
 $(378)
Electricity303
 (285) 285
 (275)
Other7
 (1) 9
 (1)
Foreign currency exchange contracts4
 
 1
 (3)
Total derivatives not designated as hedging instruments$663
 $(666) $652
 $(657)
        
Current$563
 $(518) $540
 $(558)
Noncurrent100
 (151) 112
 (99)
Total derivatives$663
 $(669) $652
 $(657)
The following table presents the fair value of December 31, 2015 and 2014derivative instruments for DTE Electric:
December 31,December 31,
2015 20142018 2017
(In millions)(In millions)
FTRs — Other current assets$3
 $3
$6
 $9
Total derivatives not designated as hedging instrument$3
 $3
Total derivatives not designated as hedging instruments$6
 $9
Certain of DTE Energy's derivative positions are subject to netting arrangements which provide for offsetting of asset and liability positions as well as related cash collateral. Such netting arrangements generally do not have restrictions. Under such netting arrangements, DTE Energy offsets the fair value of derivative instruments with cash collateral received or paid for those contracts executed with the same counterparty, which reduces DTE Energy's Total Assets and Liabilities. Cash collateral is allocated between the fair value of derivative instruments and customer accounts receivable and payable with the same counterparty on a pro ratapro-rata basis to the extent there is exposure. Any cash collateral remaining, after the exposure is netted to zero, is reflected in Accounts receivable and Accounts payable as collateral paid or received, respectively.
DTE Energy also provides and receives collateral in the form of letters of credit which can be offset against net Derivative assets and liabilities as well as Accounts receivable and payable. DTE Energy had issued letters of credit of approximately $7$4 million outstanding at December 31, 20152018 and 2014,2017, which could be used to offset net Derivative liabilities. Letters of credit received from third parties which could be used to offset net Derivative assets were $2$8 million and $5$4 million at December 31, 20152018 and 2014,2017, respectively. Such balances of letters of credit are excluded from the tables below and are not netted with the recognized assets and liabilities in DTE Energy's Consolidated Statements of Financial Position.
For contracts with certain clearing agents, the fair value of derivative instruments is netted against realized positions with the net balance reflected as either 1) a Derivative asset or liability or 2) an Account receivable or payable. Other than certain clearing agents, Accounts receivable and Accounts payable that are subject to netting arrangements have not been offset against the fair value of Derivative assets and liabilities. Certain contracts that have netting arrangements have not been offset in

DTE Energy'sEnergy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements of Financial Position. The impact of netting these derivative instruments and cash collateral related to such contracts is not material. Only the gross amounts for these derivative instruments are included in the table below.— (Continued)

For DTE Energy, the total cash collateral received, net of cash collateral posted, was $13 million as of December 31, 2018. DTE Energy had $28 million total cash collateral posted, net of cash collateral received, was $37 million and $61 million as of December 31, 20152017. DTE Energy had $17 million of cash collateral related to unrealized positions to net against Derivative assets and 2014, respectively. There was $2no cash collateral related to unrealized positions to net against Derivative liabilities as of December 31, 2018. DTE Energy had $9 million of cash collateral related to unrealized positions to net against Derivative assets while Derivative liabilities are shown net of cash collateral of $36$22 million as of December 31, 2015. There was no cash collateral related to unrealized positions to net against Derivative assets while Derivative liabilities are shown net of cash collateral of $19 million as of December 31, 2014.2017. DTE Energy recorded cash collateral paid of $10 million and cash collateral received of $6 million not related to unrealized derivative positions as of December 31, 2018. DTE Energy recorded cash collateral paid of $18 million and cash collateral received of $3 million not related to unrealized derivative positions as of December 31, 2015. DTE Energy recorded cash collateral paid of $44 million and cash collateral received of $2 million not related to unrealized derivative positions as of December 31, 2014.2017. These amounts are included in Accounts receivable and Accounts payable and are recorded net by counterparty.

99


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following table presents the netting offsets of Derivative assets and liabilities for DTE Energy at December 31, 2015 and 2014:Energy:
 December 31, 2015 December 31, 2014
 Gross Amounts of Recognized Assets (Liabilities) Gross Amounts Offset in the Consolidated Statements of Financial Position Net Amounts of Assets (Liabilities) Presented in the Consolidated Statements of Financial Position Gross Amounts of Recognized Assets (Liabilities) Gross Amounts Offset in the Consolidated Statements of Financial Position Net Amounts of Assets (Liabilities) Presented in the Consolidated Statements of Financial Position
 (In millions)
Derivative assets:           
Commodity Contracts:           
Natural Gas$387
 $(285) $102
 $787
 $(681) $106
Electricity307
 (232) 75
 342
 (280) 62
Other5
 (2) 3
 45
 (42) 3
Other derivative contracts (a)12
 (9) 3
 4
 (3) 1
Total derivative assets$711
 $(528) $183
 $1,178
 $(1,006) $172
            
Derivative liabilities:           
Commodity Contracts:           
Natural Gas$(383) $294
 $(89) $(718) $679
 $(39)
Electricity(305) 253
 (52) (342) 298
 (44)
Other(10) 8
 (2) (45) 45
 
Other derivative contracts (a)(7) 7
 
 (5) 3
 (2)
Total derivative liabilities$(705) $562
 $(143) $(1,110) $1,025
 $(85)
 December 31, 2018 December 31, 2017
 Gross Amounts of Recognized Assets (Liabilities) Gross Amounts Offset in the Consolidated Statements of Financial Position Net Amounts of Assets (Liabilities) Presented in the Consolidated Statements of Financial Position Gross Amounts of Recognized Assets (Liabilities) Gross Amounts Offset in the Consolidated Statements of Financial Position Net Amounts of Assets (Liabilities) Presented in the Consolidated Statements of Financial Position
 (In millions)
Derivative assets           
Commodity contracts           
Natural gas$349
 $(277) $72
 $357
 $(256) $101
Electricity303
 (252) 51
 285
 (241) 44
Other7
 (1) 6
 9
 
 9
Foreign currency exchange contracts4
 
 4
 1
 (1) 
Total derivative assets$663
 $(530) $133
 $652
 $(498) $154
            
Derivative liabilities           
Commodity contracts           
Natural gas$(380) $272
 $(108) $(378) $263
 $(115)
Electricity(285) 240
 (45) (275) 246
 (29)
Other(1) 1
 
 (1) 1
 
Interest rate contracts(3) 
 (3) 
 
 
Foreign currency exchange contracts
 
 
 (3) 1
 (2)
Total derivative liabilities$(669) $513
 $(156) $(657) $511
 $(146)

(a)Primarily includes foreign currency exchange contracts.
The following table presents the netting offsets of Derivative assets and liabilities showing the reconciliation of derivative instruments to DTE Energy's Consolidated Statements of Financial Position at December 31, 2015 and 2014:Position:
December 31, 2015 December 31, 2014December 31, 2018 December 31, 2017
Derivative Assets Derivative Liabilities Derivative Assets Derivative LiabilitiesDerivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities
Current Noncurrent Current Noncurrent Current Noncurrent Current NoncurrentCurrent Noncurrent Current Noncurrent Current Noncurrent Current Noncurrent
(In millions)(In millions)
Total fair value of derivatives$570
 $141
 $(521) $(184) $1,083
 $95
 $(1,041) $(69)$563
 $100
 $(518) $(151) $540
 $112
 $(558) $(99)
Counterparty netting(441) (85) 441
 85
 (955) (51) 955
 51
(451) (62) 451
 62
 (437) (52) 437
 52
Collateral adjustment
 (2) 23
 13
 
 
 9
 10
(10) (7) 
 
 
 (9) 22
 
Total derivatives as reported$129
 $54
 $(57) $(86) $128
 $44
 $(77) $(8)$102
 $31
 $(67) $(89) $103
 $51
 $(99) $(47)

100


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The effect of derivatives not designated as hedging instruments on DTE Energy's Consolidated Statements of Operations for years ended December 31, 2015 and 2014 is as follows:
 Location of Gain (Loss) Recognized in Income on Derivatives Gain (Loss) Recognized in Income on Derivatives for Years Ended December 31,
 2018 2017 2016
 Location of Gain
(Loss) Recognized
in Income on Derivatives
 Gain (Loss) Recognized in
Income on Derivatives for
Years Ended December 31,
 (In millions)
Derivatives not Designated as Hedging Instruments 2015 2014      
 (In millions)
Foreign currency exchange contracts Operating Revenues — Non-utility operations $3
 $(2)
Commodity Contracts:      
Natural Gas Operating Revenues — Non-utility operations (34) (30)
Natural Gas Fuel, purchased power, and gas — non-utility (44) (5)
Commodity contracts      
Natural gas Operating Revenues — Non-utility operations $(42) $(74) $(153)
Natural gas Fuel, purchased power, and gas — non-utility (94) 97
 (2)
Electricity Operating Revenues — Non-utility operations 54
 123
 Operating Revenues — Non-utility operations 49
 105
 43
Other Operating Revenues — Non-utility operations (7) (7) Operating Revenues — Non-utility operations (1) 2
 5
Foreign currency exchange contracts Operating Revenues — Non-utility operations 7
 (2) (2)
Total $(28) $79
 $(81) $128
 $(109)
Revenues and energy costs related to trading contracts are presented on a net basis in DTE Energy's Consolidated Statements of Operations. Commodity derivatives used for trading purposes, and financial non-trading commodity derivatives, are accounted for using the MTM method with unrealized and realized gains and losses recorded in Operating Revenues — Non-utility operations. Non-trading physical commodity sale and purchase derivative contracts are generally accounted for using the MTM method with unrealized and realized gains and losses for sales recorded in Operating Revenues — Non-utility operations and purchases recorded in Fuel, purchased power, and gas — non-utility.
The following represents the cumulative gross volume of DTE Energy's derivative contracts outstanding as of December 31, 2015:2018:
Commodity Number of Units
Natural Gas (MMBtu) 1,740,824,9302,171,541,994
Electricity (MWh) 27,668,865
Oil (Gallons)21,756,00036,163,761
Foreign Currency Exchange (Canadian dollars) 72,328,008101,975,644
Various subsidiaries of DTE Energy have entered into contracts which contain ratings triggers and are guaranteed by DTE Energy. These contracts contain provisions which allow the counterparties to require that DTE Energy post cash or letters of credit as collateral in the event that DTE Energy’s credit rating is downgraded below investment grade. Certain of these provisions (known as “hard triggers”"hard triggers") state specific circumstances under which DTE Energy can be required to post collateral upon the occurrence of a credit downgrade, while other provisions (known as “soft triggers”"soft triggers") are not as specific. For contracts with soft triggers, it is difficult to estimate the amount of collateral which may be requested by counterparties and/or which DTE Energy may ultimately be required to post. The amount of such collateral which could be requested fluctuates based on commodity prices (primarily natural gas, power, and coal) and the provisions and maturities of the underlying transactions. As of December 31, 2015,2018, DTE Energy's contractual obligation to post collateral in the form of cash or letters of credit in the event of a downgrade to below investment grade, under both hard trigger and soft trigger provisions, was approximately $412$638 million.
As of December 31, 2015,2018, DTE Energy had approximately $592$541 million of derivatives in net liability positions, for which hard triggers exist. Collateral of approximately $5 millionThere is no collateral that has been posted against such liabilities, including cash and letters of credit. Associated derivative net asset positions for which contractual offset exists were approximately $500$495 million. The net remaining amount of approximately $87$46 million is derived from the $412$638 million noted above.


101


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)


NOTE 1314 — LONG-TERM DEBT
Long-Term Debt
DTE Energy's long-term debt outstanding and weighted average interest rates (a) of debt outstanding at December 31 were:
 2015 2014
 (In millions)
Mortgage bonds, notes, and other   
DTE Energy Debt, Unsecured   
4.4% due 2016 to 2033$1,947
 $1,647
DTE Electric Taxable Debt, Principally Secured   
4.4% due 2016 to 20455,314
 4,824
DTE Electric Tax-Exempt Revenue Bonds (b)   
5.2% due 2020 to 2030310
 330
DTE Gas Taxable Debt, Principally Secured   
4.9% due 2018 to 20451,124
 1,099
Other Long-Term Debt, Including Non-Recourse Debt110
 121
DTE Energy Total Long-Term Debt8,805
 8,021
Less amount due within one year for DTE Energy(465) (161)
 $8,340
 $7,860
DTE Electric Securitization Bonds   
6.6% due 2015$
 $105
Less amount due within one year
 (105)
 $
 $
DTE Energy Junior Subordinated Debentures   
6.5% due 2061$280
 $280
5.25% due 2062200
 200
 $480
 $480
DTE Electric's long-term debt outstanding and weighted average interest rates (a) of debt outstanding at December 31 were:
 2015 2014
 (In millions)
Mortgage bonds, notes, and other   
DTE Electric Taxable Debt, Principally Secured   
4.4% due 2016 to 2045$5,314
 $4,824
DTE Electric Tax-Exempt Revenue Bonds (b) 
  
5.2% due 2020 to 2030310
 330
DTE Electric Total Long-Term Debt5,624
 5,154
Less amount due within one year for DTE Electric(151) (10)
 $5,473
 $5,144
DTE Electric Securitization Bonds   
6.6% due 2015$
 $105
Less amount due within one year
 (105)
 $
 $
 
Interest Rate(a)
 Maturity Date 2018 2017
     (In millions)
Mortgage bonds, notes, and other       
DTE Energy Debt, Unsecured3.2% 2019 — 2033 $4,425
 $3,825
DTE Electric Taxable Debt, Principally Secured4.3% 2020 — 2048 6,280
 5,755
DTE Electric Tax-Exempt Revenue Bonds(b)
4.3% 2020 — 2030 310
 310
DTE Gas Taxable Debt, Principally Secured4.5% 2019 — 2048 1,550
 1,330
Other Long-Term Debt, including Non-Recourse Debt    1
 7
     12,566
 11,227
Unamortized debt discount and premium, net    (16) (15)
Unamortized debt issuance costs    (73) (69)
Long-term debt due within one year    (1,495) (104)
     $10,982
 $11,039
Junior Subordinated Debentures       
Subordinated Debentures5.5% 2062 — 2077 $1,180
 $1,180
Unamortized debt issuance costs    (35) (35)
     $1,145
 $1,145

(a)Weighted average interest ratesrate as of December 31, 2015 are shown below the description of each category of debt.2018.
(b)DTE Electric Tax-Exempt Revenue Bonds are issued by a public body that loans the proceeds to DTE Electric on terms substantially mirroring the Revenue Bonds.

DTE Electric's long-term debt outstanding and weighted average interest rates of debt outstanding at December 31 were:
102

 
Interest Rate(a)
 Maturity Date 2018 2017
     (In millions)
Mortgage bonds, notes, and other       
Taxable Debt, Principally Secured4.3% 2020 — 2048 $6,280
 $5,755
Tax-Exempt Revenue Bonds(b)
4.3% 2020 — 2030 310
 310
     6,590
 6,065
Unamortized debt discount    (11) (10)
Unamortized debt issuance costs    (41) (38)
     $6,538
 $6,017

(a)Weighted average interest rate as of December 31, 2018.
(b)Tax-Exempt Revenue Bonds are issued by a public body that loans the proceeds to DTE Electric on terms substantially mirroring the Revenue Bonds.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)


Debt Issuances
In 2015,2018, the following debt was issued:
Company Month Type Interest Rate Maturity Amount Month Type Interest Rate Maturity Date Amount
 (In millions) (In millions)
DTE Electric March Mortgage Bonds (a) 3.70% 2045 $500
 May 
Mortgage Bonds(a)
 4.05% 2048 $525
DTE Energy June Senior Notes (b) 3.30% 2022 300
 August 
Senior Notes(b)
 3.70% 2023 600
DTE Gas August Mortgage Bonds (c) 3.35% 2027 40
 August 
Mortgage Bonds(b)
 3.81% 2028 195
DTE Gas August Mortgage Bonds (c) 4.21% 2045 125
 August 
Mortgage Bonds(b)
 4.14% 2048 125
 $965
 $1,445

(a)ProceedsBonds were issued as Green Bonds and the proceeds will be used to finance expenditures for the redemption of long-term debt, repayment of short-term borrowings,solar and general corporate purposes.wind energy, payments under power purchase agreements for solar and wind energy, and energy optimization programs.
(b)Proceeds were used for general corporate purposes.
(c)Proceeds were used for the redemptionrepayment of long-term debtshort-term borrowings and general corporate purposes.
Debt Redemptions
In 2015,2018, the following debt was redeemed:
Company Month Type Interest Rate Maturity Amount Month Type Interest Rate Maturity Date Amount
   (In millions)   (In millions)
DTE Electric March Securitization Bonds 6.62% 2015 $105
DTE Electric March Mortgage Bonds 7.904% 2016 10
DTE Gas September Senior Notes 5.94% 2015 140
 April Senior Notes 6.04% 2018 $100
DTE Electric December Tax-Exempt Revenue Bonds 5.00% 2015 20
DTE Energy Various Other Long-Term Debt Various 2015 11
 Various Other Long-Term Debt Various 2018 5
 $286
 $105
The following table shows the Registrants' scheduled debt maturities, excluding any unamortized discount or premium on debt:
2016 2017 2018 2019 2020 2021 and Thereafter Total2019 2020 2021 2022 2023 2024 and Thereafter Total
(In millions)(In millions)
DTE Energy (a)$465
 $9
 $407
 $427
 $688
 $7,304
 $9,300
$1,495
 $682
 $462
 $616
 $1,177
 $9,314
 $13,746
DTE Electric$151
 $
 $300
 $
 $632
 $4,552
 $5,635
$
 $632
 $462
 $316
 $202
 $4,978
 $6,590

(a)Amounts include DTE Electric's scheduled debt maturities.
Junior Subordinated Debentures
At December 31, 2015,2018, DTE Energy had $280 million of 6.5%the following Junior Subordinated Debentures due 2061 and $200 million of 5.25% Junior Subordinated Debentures due 2062. Debentures:
 Interest Rate Maturity Date Amount
     (In millions)
2012 Series C5.25% 2062 $200
2016 Series B5.375% 2076 300
2016 Series F6.00% 2076 280
2017 Series E5.25% 2077 400
     $1,180
DTE Energy has the right to defer interest payments on the debt securities. Should DTE Energy exercise this right, it cannot declare or pay dividends on, or redeem, purchase or acquire, any of its capital stock during the deferral period. Any deferred interest payments will bear additional interest at the rate associated with the related debt issue. As of December 31, 2015,2018, no interest payments have been deferred on the debt securities.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Cross Default Provisions
Substantially all of the net utility properties of DTE Electric and DTE Gas are subject to the lien of mortgages. Should DTE Electric or DTE Gas fail to timely pay their indebtedness under these mortgages, such failure may create cross defaults in the indebtedness of DTE Energy.

Acquisition Financing

Effective October 1, 2016, DTE Energy closed on the purchase of midstream natural gas assets. DTE Energy purchased 100% of AGS, located in Pennsylvania and West Virginia, and 40% of SGG, located in West Virginia, from M3 Midstream. In addition, DTE Energy purchased 15% of SGG from Vega Energy Partners, resulting in 55% total ownership of SGG by DTE Energy. The acquisition was financed through the issuance of Equity Units and Senior Notes.
103In October 2016, DTE issued $675 million of Equity Units. Each Equity Unit has a stated amount of $50, initially in the form of a Corporate Unit, is comprised of (i) a forward purchase contract to buy DTE Energy common stock (stock purchase contract) and (ii) a 1/20 undivided beneficial ownership interest in $1,000 principal amount of DTE Energy’s 2016 Series C 1.5% RSNs due 2024. The RSN debt instruments and the stock purchase contract equity instruments are deemed to be separate instruments as the investor may trade the RSNs separately from the stock purchase contracts and may also settle the stock purchase contracts separately. The Corporate Units are listed on the New York Stock Exchange under the symbol DTV.
The stock purchase contract obligates the holder to purchase from DTE Energy on the settlement date, October 1, 2019, for a price of $50 per stock purchase contract, the following number of shares of DTE Energy’s common stock, subject to anti-dilution adjustments:

if the AMV of DTE Energy’s common stock, which is the average volume-weighted average price of DTE Energy’s common stock for the trading days during the 20 consecutive scheduled trading day period ending on the third scheduled trading day immediately preceding the stock purchase contract settlement date, is equal to or greater than $116.31, 0.4299 shares of common stock;
if the AMV is less than $116.31 but greater than $93.05, a number of shares of common stock equal to $50 divided by the AMV, rounded to the nearest 1/10,000th of a share; and
if the AMV is less than or equal to $93.05, 0.5373 shares of common stock.
The RSNs bear interest at a rate of 1.5% per year, payable quarterly, and mature on October 1, 2024. The RSNs will be remarketed in 2019. If this remarketing is successful, the interest rate on the RSNs will be reset, and thereafter interest will be payable semi-annually at the reset rate. If there is no successful remarketing, the interest rate on the RSNs will not be reset, and the holders of the RSNs will have the right to put the RSNs to DTE Energy at a price equal to 100% of the principal amount, and the proceeds of the put right will be deemed to have been applied against the holders’ obligation under the stock purchase contracts. DTE Energy may also redeem, in whole or in part, the RSNs in the event of a failed final remarketing.
On January 1, 2017, DTE Energy began paying the stock purchase contract holders quarterly contract adjustment payments at a rate of 5% per year of the stated amount of $50 per Equity Unit, or $2.50 per year. The present value of the future contract adjustment payments of $98 million was recorded as a reduction of shareholders’ equity, offset by the stock purchase contract liability. The stock purchase contract liability is included in Current Liabilities — Other and Other Liabilities — Other on DTE Energy’s Consolidated Statements of Financial Position. Interest payments on the RSNs are recorded as interest expense and stock purchase contract payments are charged against the liability. Accretion of the stock purchase contract liability is recorded as imputed interest expense. The treasury stock method is used to compute diluted EPS for the stock purchase contract. Under the treasury stock method, the stock purchase contract will only have a dilutive effect when the settlement rate is based on the market value of DTE’s common stock that is greater than $116.31 (the threshold appreciation price). At December 31, 2018, the stock purchase price contract was anti-dilutive and, therefore, not included in the computation of diluted earnings per share. If payments for the stock purchase contract are deferred, DTE Energy may not make any cash distributions related to its capital stock, including dividends, redemptions, repurchases, liquidation payments or guarantee payments. Also, during the deferral period, DTE Energy may not make any payments on or redeem or repurchase any debt securities that are equal in right of payment with, or subordinated to, the RSNs.
Until settlement of the stock purchase contracts, the shares of stock underlying each contract are not outstanding. Under the terms of the stock purchase contracts, assuming no anti-dilution or other adjustments, DTE Energy will issue between 5.8 million and 7.3 million shares of its common stock in October 2019. A total of 9 million shares of DTE Energy’s common stock have been reserved for issuance in connection with the stock purchase contracts.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Selected information about DTE Energy’s 2016 Equity Units is presented below:
Issuance Date Units Issued Total Net Proceeds Total Long-Term Debt RSN Annual Interest Rate Stock Purchase Contract Annual Rate Stock Purchase Settlement Date 
Stock Purchase Contract Liability(a)
 RSN Maturity Date
(In millions, except interest rates)
10/5/2016 13.5 $654
 $675
 1.5% 5.0% 10/1/2019 $98
 10/1/2024

(a)Payments of $33 million and $32 million were made in 2018 and 2017, respectively. The stock purchase contract liability, exclusive of interest, was $33 million and $66 million at December 31, 2018 and 2017, respectively.

NOTE 1415 — PREFERRED AND PREFERENCE SECURITIES
As of December 31, 2015,2018, the amount of authorized and unissued stock is as follows:
Company Type of Stock Par Value Shares Authorized
DTE Energy Preferred $
 5,000,000
DTE Electric Preferred $100
 6,747,484
DTE Electric Preference $1
 30,000,000
DTE Gas Preferred $1
 7,000,000
DTE Gas Preference $1
 4,000,000

NOTE 1516 — SHORT-TERM CREDIT ARRANGEMENTS AND BORROWINGS
DTE Energy, DTE Electric, and DTE Gas have unsecured revolving credit agreements that can be used for general corporate borrowings, but are intended to provide liquidity support for each of the companies’ commercial paper programs. Borrowings under the facilitiesrevolvers are available at prevailing short-term interest rates. Additionally, DTE Energy has other facilities to support letter of credit issuance.
The agreements require DTE Energy, DTE Electric, and DTE Gas to maintain a total funded debt to capitalization ratio of no more than 0.65 to 1. In the agreements, “total"total funded debt”debt" means all indebtedness of each respective company and their consolidated subsidiaries, including capital lease obligations, hedge agreements, and guarantees of third parties’ debt, but excluding contingent obligations, nonrecourse and junior subordinated debt, and certain equity-linked securities and, except for calculations at the end of the second quarter, certain DTE Gas short-term debt. “Capitalization”"Capitalization" means the sum of (a) total funded debt plus (b) “consolidated"consolidated net worth," which is equal to consolidated total equity of each respective company and their consolidated subsidiaries (excluding pension effects under certain FASB statements), as determined in accordance with accounting principles generally accepted in the United States of America. At December 31, 2015,2018, the total funded debt to total capitalization ratios for DTE Energy, DTE Electric, and DTE Gas were 0.510.55 to 1, 0.510.50 to 1, and 0.48 to 1, respectively, and arewere in compliance with this financial covenant.
The availability under the facilities in place at December 31, 2015 is shown in the following table:
 DTE Energy DTE Electric DTE Gas Total
 (In millions)
Unsecured letter of credit facility, expiring in February 2017$100
 $
 $
 $100
Unsecured letter of credit facility, expiring in September 201770
 
 
 70
Unsecured revolving credit facility, expiring April 20201,200
 400
 300
 1,900
 1,370
 400
 300
 2,070
Amounts outstanding at December 31, 2015       
Commercial paper issuances33
 272
 194
 499
Letters of credit130
 
 
 130
 163
 272
 194
 629
Net availability at December 31, 2015$1,207
 $128
 $106
 $1,441
DTE Energy has other outstanding letters of credit which are not included in the above described facilities totaling approximately $17 million which are used for various corporate purposes.
The weighted average interest rate for short-term borrowings was 0.6% and 0.4% at December 31, 2015 and 2014, respectively, for DTE Energy. The weighted average interest rate for short-term borrowings was 0.7% and 0.5% at December 31, 2015 and 2014, respectively, for DTE Electric.

104


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The availability under the facilities in place at December 31, 2018 is shown in the following table:
 DTE Energy DTE Electric DTE Gas Total
 (In millions)
Unsecured letter of credit facility, expiring in February 2019$150
 $
 $
 $150
Unsecured letter of credit facility, expiring in September 201970
 
 
 70
Unsecured revolving credit facility, expiring April 20221,200
 400
 300
 1,900
 1,420
 400
 300
 2,120
Amounts outstanding at December 31, 2018       
Commercial paper issuances271
 149
 189
 609
Letters of credit168
 
 
 168
 439
 149
 189
 777
Net availability at December 31, 2018$981
 $251
 $111
 $1,343
DTE Energy has $9 million of other outstanding letters of credit which are used for various corporate purposes and are not included in the facilities described above.
The weighted average interest rate for short-term borrowings was 2.9% and 1.9% at December 31, 2018 and 2017, respectively, for DTE Energy. The weighted average interest rate for short-term borrowings was 2.9% and 1.5% at December 31, 2018 and 2017, respectively, for DTE Electric.
In conjunction with maintaining certain exchange tradedexchange-traded risk management positions, DTE Energy may be required to post collateral with its clearing agent. DTE Energy has a demand financing agreement for up to $100 million with its clearing agent. The agreement, as amended, also allows for up to $50 million of additional margin financing provided that DTE Energy posts a letter of credit for the incremental amount and allows the right of setoff with posted collateral. At December 31, 2015, a $25 million letter of credit was in place, raising2018, the capacity under this facility towas $125 million. The $25 million letter of credit is included in the table above. The amount outstanding under this agreement was $103$93 million and $37$56 million at December 31, 20152018 and 2014,2017, respectively, and was fully offset by the posted collateral.
Dividend Restrictions
Certain of DTE Energy’s credit facilities contain a provision requiring DTE Energy to maintain a total funded debt to capitalization ratio, as defined in the agreements, of no more than 0.65 to 1, which has the effect of limiting the amount of dividends DTE Energy can pay in order to maintain compliance with this provision. At December 31, 2015,2018, the effect of this provision was to restrict the payment of approximately $920 million$2.4 billion of Retained earnings totaling $4.8$6.1 billion. There are no other effective limitations with respect to DTE Energy’s ability to pay dividends.

NOTE 1617 — CAPITAL AND OPERATING LEASES
Lessee
Lessee - Operating Lease — The Registrants lease various assets under operating leases, including coal railcars, office buildings, a warehouse, computers, vehicles, and other equipment. The lease arrangements expire at various dates through 2046.
The Registrants' future minimum lease payments under non-cancelable leases at December 31, 2015 were:
 DTE Energy DTE Electric
 Operating
Leases
 Operating
Leases
 (In millions)
2016$37
 $24
201730
 18
201825
 15
201921
 14
202013
 10
Thereafter71
 35
Total minimum lease payments$197
 $116
Rental expense2051 and 2046 for DTE Energy operating leases was $43 million in 2015, $38 million in 2014, and $34 million in 2013, including rental expense for DTE Electric, operating leases of $32 million in 2015, $26 million in 2014, and $28 million in 2013.respectively.

105


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The Registrants' future minimum lease payments under non-cancelable operating leases at December 31, 2018 were:
 DTE Energy DTE Electric
 (In millions)
2019$42
 $17
202030
 12
202118
 10
202211
 7
20238
 5
2024 and thereafter45
 29
Total minimum lease payments$154
 $80
Rental expense for DTE Energy operating leases was $44 million in 2018, $51 million in 2017, and $43 million in 2016, including rental expense for DTE Electric operating leases of $18 million in 2018 and $28 million in 2017 and 2016.
Lessor
LessorOperating Lease - — DTE Energy leases various assets under operating leases for energy facilities and related equipment. DTE Energy's minimum future rental revenues under non-cancelable operating leases as of December 31, 2018 were:
 DTE Energy
 (In millions)
2019$66
202066
202164
202220
202320
2024 and thereafter196
Total minimum future rental revenue under non-cancelable operating leases$432
The amounts listed above do not include contingent rentals associated with the leased assets. DTE Energy had contingent rental revenues of $107 million, $91 million, and $101 million in 2018, 2017, and 2016, respectively.
Capital Lease — DTE Energy leases a portion of its pipeline system to the Vector Pipeline through a capital lease contract that expires in 2020, with renewal options extending for five years. DTE Energy owns a 40% interest in the Vector Pipeline. In addition, DTE Energy has antwo energy services agreement,agreements, for which a portion of which isare accounted for as a capital lease. The agreement expiresleases. These agreements expire in 2019 with a three or five year renewal option. and 2026.
The components of DTE Energy's net investment in capital leases at December 31, 2015,2018, were as follows:
DTE EnergyDTE Energy
Capital
Leases
(In millions)
(In millions)
2016$13
201713
201813
201910
$10
20209
9
Thereafter
2021
2022
2023
2024 and thereafter1
Total minimum future lease receipts58
20
Residual value of leased pipeline40
40
Less unearned income(27)(9)
Net investment in capital lease71
51
Less current portion(6)(5)
$65
$46

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)


NOTE 1718 — COMMITMENTS AND CONTINGENCIES
Environmental
DTE Electric
Air — DTE Electric is subject to the EPA ozone and fine particulate transport and acid rain regulations that limit power plant emissions of sulfur dioxideSO2 and nitrogen oxides.NOX. The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to controls on fossil-fueled power plants to reduce nitrogen oxide, sulfur dioxide,SO2, NOX, mercury, and other emissions. Additional rulemakings are expectedmay occur over the next few years which could require additional controls for sulfur dioxide, nitrogen oxides, and hazardous air pollutants.SO
The Cross State Air Pollution Rule (CSAPR)2, required further reductions of sulfur dioxide and nitrogen oxides emissions beginning in January 2015. DTE Electric expects to meet its obligations under CSAPR. In November 2015, the EPA proposed an update to the CSAPR ozone season program by issuing the CSAPR Update Rule. The proposed rule was subsequently published in the Federal Register in December 2015. Beginning in 2017, this proposal would reduce summertime (May - September) emissions of oxides of nitrogen (NOX) from power plants in 23 states in the eastern half of the U.S.NOX, including DTE Energy facilities. The CSAPR Update Rule is intended to reduce air quality impacts of the interstate transport of air pollution on downwind areas' ability to meet the 2008 ozone standard and to respond to the July 2015 remand of certain CSAPR budgets by the U.S. Court of Appeals for the D.C. Circuit. EPA expects to promulgate the final rule in the summer of 2016. It is not possible to quantify the impact of this rulemaking at this time.

106


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The Mercury and Air Toxics Standards (MATS) rule, formerly known as the Electric Generating Unit Maximum Achievable Control Technology (EGU MACT) Rule was finalized in December 2011. The MATS rule required reductions of mercury and other hazardous air pollutants beginning in April 2015. DTE Electric requested and was granted compliance date extensions for all relevant units to April 2016. DTE Electric has tested several technologies as MATS compliance alternatives to Flue Gas Desulfurization (FGD) systems to determine technological and economic feasibility. Dry Sorbent Injection (DSI) and Activated Carbon Injection (ACI) technologies were deemed feasible and their implementation will allow units that would not have been economical for FGD installations to continue operation in compliance with MATS. In November 2014, the U.S. Supreme Court agreed to review a challenge to the MATS rule based on a narrowly focused question of how the EPA considered costs in regulating air pollutants emitted by electric utilities. In June 2015, the U.S. Supreme Court reversed the decision of the Court of Appeals for the D.C. District and remanded the MATS rule to the Court of Appeals for further consideration based on their decision that the EPA must consider costs prior to deciding to regulate under the provisions of the Clean Air Act. Subsequently, in December 2015, the Court of Appeals ordered a remand of the MATS rule back to the EPA without staying the rule. DTE Electric does not expect this decision to have a material effect on its compliance plans at this time.pollutants.
The EPA proposed revised air quality standards for ground level ozone in November 2014 and specifically requested comments on the form and level of the ozone standards. The standards were finalized in October 2015. The State of Michigan will recommend designations byrecommended to the EPA in October 2016 andwhich areas of the state are not attaining the new standard. On April 30, 2018, the EPA will finalize designationsfinalized the state of Michigan's recommended non-attainment designation for southeast Michigan. The State is required to develop and implement a plan to address the southeast Michigan ozone non-attainment area by October 2017.2021. DTE Electric cannot predict the financial impact of the revisedState's plan to address the ozone standardsnon-attainment area at this time.
In July 2009, DTE Energy received a NOV/FOV from the EPA alleging, among other things, that five DTE Electric power plants violated New Source Performance standards, Prevention of Significant Deterioration requirements, and operating permit requirements under the Clean Air Act. In June 2010, the EPA issued a NOV/FOV making similar allegations related to a project and outage at Unit 2 of the Monroe Power Plant. In March 2013, DTE Energy received a supplemental NOV from the EPA relating to the July 2009 NOV/FOV. The supplemental NOV alleged additional violations relating to the New Source Review provisions under the Clean Air Act, among other things.
In August 2010, the U.S. Department of Justice, at the request of the EPA, brought a civil suit in the U.S. District Court for the Eastern District of Michigan against DTE Energy and DTE Electric, related to the June 2010 NOV/FOV and the outage work performed at Unit 2 of the Monroe Power Plant, but not relating to the July 2009 NOV/FOV. Among other relief, the EPA requested the court to require DTE Electric to install and operate the best available control technology at Unit 2 of the Monroe Power Plant. Further, the EPA requested the court to issue a preliminary injunction to require DTE Electric to (i) begin the process of obtaining the necessary permits for the Monroe Unit 2 modification and (ii) offset the pollution from Monroe Unit 2 through emissions reductions from DTE Electric's fleet of coal-fired power plants until the new control equipment is operating. In August 2011, the U.S. District Court judge granted DTE Energy's motion for summary judgment in the civil case, dismissing the case and entering judgment in favor of DTE Energy and DTE Electric. In October 2011, the EPA caused to be filed a Notice of Appeal to the Court of Appeals for the Sixth Circuit. In March 2013, the Court of Appeals remanded the case to the U.S. District Court for review of the procedural component of the New Source Review notification requirements. In September 2013, the EPA caused to be filed a motion seeking leave to amend their complaint regarding the June 2010 NOV/FOV adding additional claims related to outage work performed at the Trenton Channel and Belle River power plantsPower Plants as well as additional claims related to work performed at the Monroe Power Plant. In addition, the Sierra Club caused to be filed a motion to add a claim regarding the River Rouge Power Plant. In March 2014, the U.S. District Court judge again granted again DTE Energy's motion for summary judgment dismissing the civil case related to Monroe Unit 2. In April 2014, the U.S. District Court judge granted motions filed by the EPA and the Sierra Club to amend their New Source Review complaint adding additional claims for Monroe Units 1, 2, and 3, Belle River Units 1 and 2, and Trenton Channel Unit 9 and denied the claims related to River Rouge Power Plant that were brought by the Sierra Club. In June 2014, the EPA filed a motion requesting certification for appeal of the March 2014 summary judgment decision.9. In October 2014, the EPA and the U.S. Department of Justice filed the anticipateda notice of appeal of the U.S. District Court judge's dismissal of the Monroe Unit 2 case. The amended New Source Review claims arewere all stayed untilpending resolution of the appeal is resolved by the Court of Appeals for the Sixth Circuit. Oral argumentsOn January 10, 2017, a divided panel of the Court reversed the decision of the U.S. District Court. On May 8, 2017, DTE Energy and DTE Electric filed a motion to stay the mandate pending filing of a petition for writ of certiorari with the appeal occurredU.S. Supreme Court. The Sixth Circuit granted the motion on May 16, 2017, staying the claims in the U.S. District Court until the U.S. Supreme Court disposes of the case. DTE Electric and DTE Energy filed a petition for writ of certiorari on July 31, 2017. On December 2015.11, 2017, the U.S. Supreme Court denied certiorari. As a result of the Supreme Court electing not to review the matter, the case was sent back to the U.S. District Court for further proceedings and on June 14, 2018 the case was stayed pending settlement negotiations. The proceedings at the District Court remain stayed while the parties discuss potential resolution of the matter.
The Registrants believe that the plants and generating units identified by the EPA and the Sierra Club have complied with all applicable federal environmental regulations. Depending upon the outcome of the litigation and further discussions with the EPA regarding the two NOVs/FOVs, DTE Electric could be required to install additional pollution control equipment at some or all of the power plants in question, implement early retirement of facilities where control equipment is not economical, engage in supplemental environmental programs, and/or pay fines. The Registrants cannot predict the financial impact or outcome of this matter, or the timing of its resolution.

107


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The EPA is implementinghas implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, in 2015 the EPA has finalized performance standards for emissions of carbon dioxide from new and existing fossil-fuel fired EGUs. In February 2016, the U.S. Supreme Court granted petitioners' requests for a stay of the carbon rules for existing EGUs (also known as the EPA Clean Power Plan) pending final review by the courts. The Clean Power Plan has no legal effect while the stay is in place. On March 28, 2017, a presidential executive order was issued on "Promoting Energy Independence and Economic Growth." The order instructs the EPA to review, and if appropriate, suspend, revise or rescind the Clean Power Plan rule. Following the issuance of this order, the federal government requested the U.S. Court of Appeals for the D.C. Circuit to hold all legal challenges in abeyance until the review of these regulations is completed. On October 10, 2017, the EPA proposed to rescind the Clean Power Plan and in August 2018, the EPA proposed revised emission guidelines for GHGs from existing electric utility generating units (EGUs).units. This proposed rule, named the Affordable Clean Energy (ACE) rule, is intended to replace the Clean Power Plan rule. In addition, in December 2018, the EPA issued proposed revisions to the carbon dioxide performance standards for new, modified, or reconstructed fossil-fuel fired EGUs. The carbon standards for new sources are not expected to have a material impact on DTE Electric, since DTE Electric has no plans to build new coal-fired generation and any potential new gas generation will be able to comply with the standards. It isThese proposed rules do not possibleimpact DTE Energy's goal to determinereduce carbon emissions 30% by the potential impact of the final carbon standards (also known as the EPA Clean Power Plan) on existing sources at this time. early 2020s, 45% by 2030, 75% by 2040, and more than 80% by 2050.
Pending or future legislation or other regulatory actions could have a material impact on DTE Electric's operations and financial position and the rates charged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. DTE Electric would seek to recover these incremental costs through increased rates charged to its utility customers, as authorized by the MPSC.
To comply with air pollution requirements, DTE Electric spent approximately $2.3$2.4 billion through 2015.2018. DTE Electric estimates makingdoes not anticipate additional capital expenditures of approximately $40 million in 2016.through 2025.
Water — In response to an EPA regulation, DTE Electric would bewas required to examine alternatives for reducing the environmental impacts of the cooling water intake structures at several of its facilities. Based on the results of completed studies and expected future studies, DTE Electric may be required to install technologies to reduce the impacts of the water intake structures. A final rule became effective in October 2015.2014. The final rule requires studies to be completed by April 2018and submitted as part of the National Pollutant Discharge Elimination System (NPDES) permit application process to determine the type of technology needed to reduce impacts to fish. DTE Electric has initiated the process of completing the required studies. Final compliance for the installation of any required technology will be determined by each state on a case by case, site specific basis. DTE Electric is currently evaluating the compliance options and working with the State of Michigan on evaluating whether any controls are needed. These evaluations/studies may require modifications to some existing intake structures. It is not possible to quantify the impact of this rulemaking at this time.
Contaminated and Other Sites — Prior to the construction of major interstate natural gas pipelines, gas for heating and other uses was manufactured locally from processes involving coal, coke, or oil. The facilities, which produced gas, have been designated as MGP sites. DTE Electric conducted remedial investigations at contaminated sites, including three former MGP sites. The investigations have revealed contamination related to the by-products of gas manufacturing at each MGP site. In addition to the MGP sites, DTE Electric is also in the process of cleaning up other contaminated sites, including the area surrounding an ash landfill, electrical distribution substations, electric generating power plants, and underground and aboveground storage tank locations. The findings of these investigations indicated that the estimated cost to remediate these sites is expected to be incurred over the next several years. At December 31, 20152018 and 2014,2017, DTE Electric had $8$7 million and $10$6 million, respectively, accrued for remediation, respectively.remediation. Any change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect DTE Electric’s financial position and cash flows. DTE Electric believes the likelihood of a material change to the accrued amount is remote based on current knowledge of the conditions at each site.
Coal Combustion Residuals and Effluent Limitations Guidelines — A final EPA rule for the disposal of coal combustion residuals, commonly known as coal ash, became effective in October 2015. The rule is based2015, and was revised in October 2016 and July 2018. Additionally, a D.C. District Court Decision on August 21, 2018 (effective October 12, 2018) may affect the continued listingtiming of closure of coal ash asimpoundments that are not lined with an engineered liner system. In 2019, the EPA is expected to affirmatively undertake rulemaking to implement the D.C. District Court's decision that will determine any changes to DTE Electric's plans in the operation and closure of coal ash impoundments.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

At the State level, legislation was signed by the Governor in December 2018. The bill provides for a non-hazardous wasteCCR program to be regulated in Michigan once approval is requested and relies on various self-implementation design and performance standards. received from the EPA.
DTE Electric owns and operates three permitted engineered coal ash storage facilities to dispose of coal ash from coal-fired power plants and operates a number of smaller impoundments at its power plants. At certain facilities, the rule requiresCCR obligations vary based on plant life, but include the installation of monitoring wells, compliance with groundwater standards, and the closure of landfills and basins at the end of the useful life of the associated power plant. At otherplant or as a basin becomes inactive. Under the current CCR rules and uncertainty regarding the D.C. District Court decision, capital costs and timing associated with the building of new CCR facilities the rule requires ash laden waters be moved from earthen basins to steel and concrete tanks.or retirement of existing CCR facilities are being evaluated.
In November 2015, the EPA finalized effluent limitations guidelinesthe ELG Rule for the steam electric power generating industry which may requirerequires additional controls to be installed between 2018 and 2023. Certain effluent limitations guidelinesCompliance schedules for individual facilities and individual waste streams are determined through issuance of new National Pollutant Discharge Elimination System (NPDES) permits by the State of Michigan. The State of Michigan has issued a NPDES permit for the Belle River Power Plant establishing a compliance deadline of December 31, 2021. No new permits that would require ELG compliance have been issued for other facilities, consequently no compliance timelines have been established.
On April 12, 2017, the EPA granted a petition for reconsideration of the ELG Rule. The EPA also signed an administrative stay of the ELG Rule’s compliance deadlines for fly ash transport water, bottom ash transport water, and flue gas desulfurization (FGD) wastewater, among others. On June 6, 2017, the EPA published in the Federal Register a proposed rule to postpone certain applicable deadlines within the ELG rule. The final rule was published on September 18, 2017. The final rule nullified the administrative stay but also extended the earliest compliance deadlines for the FGD wastewater and bottom ash transport water until November 1, 2020 in order for the EPA to propose and finalize a new ruling. The ELG compliance requirements and final deadlines for bottom ash transport water and FGD wastewater, and total ELG related compliance costs will not be requiredknown until the EPA completes its reconsideration of the ELG Rule.
Over the next six years, to be performed in conjunctioncomply with the coal combustion residuals requirements. CostsNovember 2015 ELG requirements and CCR requirements, costs associated with the building of new facilities over the next seven years to comply with coal combustion residuals requirements and effluent limitations guidelinesor installation of controls are estimated to be approximately $290$565 million. See Note 7 to the Consolidated Financial Statements, "Asset Retirement Obligations", for estimated costs of closure of old facilities.

108


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

DTE Gas
Contaminated and Other Sites— DTE Gas owns or previously owned, 14 former MGP sites. Investigations have revealed contamination related to the by-products of gas manufacturing at each site. Cleanup of fivesix of the MGP sites is complete and the sites are closed. DTE Gas has also completed partial closure of twosix additional sites. Cleanup activities associated with the remaining sites will continue over the next several years. The MPSC has established a cost deferral and rate recovery mechanism for investigation and remediation costs incurred at former MGP sites. In addition to the MGP sites, DTE Gas is also in the process of cleaning up other contaminated sites, including gate stations, gas pipeline releases, and underground storage tank locations. As of December 31, 20152018 and 2014,2017, DTE Gas had $22$25 million and $24$41 million, respectively, accrued for remediation, respectively.remediation. Any change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect DTE Gas' financial position and cash flows. DTE Gas anticipates the cost amortization methodology approved by the MPSC, which allows for amortization of the MGP costs over a ten-year period beginning with the year subsequent to the year the MGP costs were incurred, will prevent environmental costs from having a material adverse impact on DTE Gas' results of operations.
Non-utility
DTE Energy’sEnergy's non-utility businesses are subject to a number of environmental laws and regulations dealing with the protection of the environment from various pollutants.
The Michigan coke battery facility received and responded to information requests from the EPA that resulted in the issuance of a NOV in June 2007 alleging potential maximum achievable control technologies and new source review violations. The EPA is in the process of reviewing DTE Energy’s position of demonstrated compliance and has not initiated escalated enforcement. At this time, DTE Energy cannot predict the impact of this issue but expects no further action. Furthermore, the Michigan coke battery facility is the subject of an investigation by the MDEQ concerning visible emissions readings that resulted from DTE Energy self reporting to MDEQ questionable activities by an employee of a contractor hired by DTE Energy to perform the visible emissions readings. At this time, DTE Energy cannot predict the impact of this investigation.
The Shenango coke battery received two NOVs from the Pennsylvania Department of Environmental Protection (PADEP) in 2010 alleging violations of the permit for the Pennsylvania coke battery facility in connection with coal pile storm water runoff. DTE Energy settled the alleged violations by implementing best management practices to address the issues and repair/upgrade its wastewater treatment plant. DTE Energy received a construction permit to upgrade its existing waste water treatment system. Due to the December 2015 decision to close the Shenango coke battery in January 2016, DTE Energy will not proceed with the upgrade to its wastewater treatment system.
The Shenango coke battery received an NOV from the Allegheny County, PA Health Department pertaining to excessive opacity readings from fugitive sources in excess of its standards for the Pennsylvania coke battery facility. Fugitive sources at the plant are in full compliance with the applicable Federal Opacity Standards. DTE Energy agreed to a Consent Order and Agreement with Allegheny County pursuant to which DTE Energy paid a fine of $300,000 and spent $300,000 for a supplemental environmental project. In May 2014, the Group Against Smog & Pollution (GASP) filed a complaint alleging that DTE Energy's coke battery facility in Pennsylvania was in violation of visible emissions limits under the Federal Clean Air Act and/or Article XXI of the Allegheny County, PA Health Department's Rules and Regulations. DTE Energy believed that the GASP suit was without merit and filed a motion to dismiss in July 2014. In March 2015, the U.S. District Court granted DTE Energy's motion for dismissal. In April 2015, GASP filed a notice of appeal. In January 2016, the U.S. Court of Appeals for the Third Circuit affirmed the judgment of dismissal.
Other
In 2010, the EPA finalized a new 1-hour sulfur dioxideone-hour SO2 ambient air quality standard that requires states to submit plans and associated timelines for non-attainment areas that demonstrate attainment with the new SO2 standard in phases. Phase 1 addresses non-attainment areas designated based on ambient monitoring data. Phase 2 addresses non-attainment areas with large sources of SO2 and modeled concentrations exceeding the National Ambient Air Quality Standards for SO2. Phase 3 addresses smaller sources of SO2 with modeled or monitored exceedances of the new SO2 standard.

DTE Energy Company — DTE Electric Company
Combined Notes to be in compliance by 2018. Consolidated Financial Statements — (Continued)

Michigan's Phase 1 non-attainment area includes DTE Energy facilities in southwest Detroit and areas of Wayne County. Modeling runs by the MDEQ suggest that emission reductions may be required by significant sources of sulfur dioxideSO2 emissions in these areas, including DTE Electric power plants and DTE Energy's Michigan coke battery facility. As part of the state implementation plan process, DTE Energy has worked with the MDEQ to develop air permits reflecting significant SO2 emission reductions that, in combination with other non-DTE Energy sourcessources' emission reduction strategies, will help the state attain the standard and sustain its attainment. Since several non-DTE Energy sources are also part of the proposed compliance plan, DTE Energy is unable to determine the full impact of the final required emissions reductions at this time.

109


DTE Energy Company —Michigan's Phase 2 non-attainment area includes DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Nuclear Operations
Property Insurance
DTE Electric maintains property insurance policies specificallyfacilities in St. Clair County. State implementation plan (SIP) submittal and EPA approval describing the control strategy and timeline for demonstrating compliance with the Fermi new SO2 plant. These policies cover such items as replacement power and property damage. NEIL standard is the primary supplier of the insurance policies.
DTE Electric maintains a policy for extra expenses, including replacement power costs necessitated by Fermi 2’s unavailability due to an insured event. This policy has a 12-week waiting period and provides an aggregate $490 million of coverage over a three-year period.
DTE Electric has $1.5 billion in primary coverage and $1.25 billion of excess coverage for stabilization, decontamination, debris removal, repair and/or replacement of property, and decommissioning. The combined coverage limit for total property damage is $2.75 billion. The total limit for property damage for non-nuclear events is $2 billion and an aggregate of $328 million of coverage for extra expenses over a two-year period.
On January 13, 2015, the Terrorism Risk Insurance Program Reauthorization Act of 2015 was signed, extending TRIA through December 31, 2020. For multiple terrorism losses caused by acts of terrorism not covered under the TRIA occurring within one year after the first loss from terrorism, the NEIL policies would make available to all insured entities up to $3.2 billion, plus any amounts recovered from reinsurance, government indemnity, or other sources to cover losses.
Under NEIL policies, DTE Electric could be liable for maximum assessments of up to approximately $45 million per event if the loss associated with any one event at any nuclear plant should exceed the accumulated funds available to NEIL.
Public Liability Insurance
As required by federal law, DTE Electric maintains $375 million of public liability insurance for a nuclear incident. For liabilities arising from a terrorist act outside the scope of TRIA, the policy is subject to one industry aggregate limit of $300 million. Further, under the Price-Anderson Amendments Act of 2005, deferred premium charges up to $127 million could be levied against each licensed nuclear facility, but not more than $19 million per year per facility. Thus, deferred premium charges could be levied against all owners of licensed nuclear facilitiesnext step in the event of a nuclear incident at any of these facilities.
Nuclear Fuel Disposal Costs
In accordance with the Federal Nuclear Waste Policy Act of 1982, DTE Electric has a contract with the DOE for the future storage and disposal of spent nuclear fuel from Fermi 2 that required DTE Electric to pay the DOE a fee of 1 mill per kWh of Fermi 2 electricity generated and sold. The fee was a component of nuclear fuel expense. The DOE's Yucca Mountain Nuclear Waste Repository program for the acceptance and disposal of spent nuclear fuel was terminated in 2011. DTE Electric is a party in the litigation against the DOE for both past and future costs associated with the DOE's failure to accept spent nuclear fuel under the timetable set forth in the Federal Nuclear Waste Policy Act of 1982. In July 2012, DTE Electric executed a settlement agreement with the federal government for costs associated with the DOE's delay in acceptance of spent nuclear fuel from Fermi 2 for permanent storage. The settlement agreement, including extensions, provides for a claims process and payment of delay-related costs experienced by DTE Electric through 2016. DTE Electric's claims are being settled and paid on a timely basis. The settlement proceeds reduce the cost of the dry cask storage facility assets and provide reimbursement for related operating expenses. The 1 mill per kWh DOE fee was reduced to zero effective May 16, 2014.
DTE Electric currently employs a spent nuclear fuel storage strategy utilizing a fuel pool and a newly completed dry cask storage facility. The dry cask storage facility is expected to provide sufficient spent fuel storage capability forbe completed by the lifeend of 2019. DTE Energy is currently working with the MDEQ to develop the required SIP. DTE Energy is unable to determine the full impact of the plant as defined by the original operating license.SIP strategy.
The federal government continues to maintain its legal obligation to accept spent nuclear fuel from Fermi 2 for permanent storage. Issues relating to long-term waste disposal policy and to the disposition of funds contributed by DTE Electric ratepayers to the federal waste fund await future governmental action.

110


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Synthetic Fuel Guarantees
DTE Energy discontinued the operations of its synthetic fuel production facilities throughout the United States as of December 31, 2007. DTE Energy provided certain guarantees and indemnities in conjunction with the sales of interests in its synfuel facilities. The guarantees cover potential commercial, environmental, oil price, and tax-related obligations that will survive until 90 days after expiration of all applicable statutes of limitations. DTE Energy estimates that its maximum potential liability under these guarantees at December 31, 2015 is2018 was approximately $850$400 million. Payment under these guarantees isare considered remote.
REF Guarantees
DTE Energy has provided certain guarantees and indemnities in conjunction with the sales of interests in or lease of its REF facilities. The guarantees cover potential commercial, environmental, and tax-related obligations that will survive until 90 days after expiration of all applicable statutes of limitations. DTE Energy estimates that its maximum potential liability under these guarantees at December 31, 2015 is approximately $2682018 was $359 million. PaymentPayments under these guarantees are considered remote.
NEXUS Guarantees
NEXUS entered into certain 15-year capacity lease agreements for the transportation of natural gas with DTE Gas and Texas Eastern Transmission, LP, an unrelated third party. Pursuant to the terms of those agreements, in December 2016, DTE Energy executed separate guarantee agreements with DTE Gas and Texas Eastern Transmission, LP, with maximum potential payments totaling $242 million and $377 million at December 31, 2018, respectively; each representing 50% of all payment obligations due and payable by NEXUS. Each guarantee terminates at the earlier of (i) such time as all of the guaranteed obligations have been fully performed, or (ii) two months following the end of the primary term of the capacity lease agreements. In October 2018, NEXUS Pipeline was placed in service. The amount of each guarantee decreases annually as payments are made by NEXUS to each of the aforementioned counterparties.
NEXUS also entered into certain 15-year capacity lease agreements for the transportation of natural gas with Vector, an equity method investee of DTE Energy. Pursuant to the terms of those agreements, in October 2018, DTE Energy executed a guarantee agreement with Vector, with a maximum potential payment totaling $7 million at December 31, 2018, representing 50% of the first-year payment obligations due and payable by NEXUS. The guarantee terminates at the earlier of (i) such time as all of the guaranteed obligations have been fully performed or (ii) 15 years from the date DTE Energy entered into the guarantee.
Should NEXUS fail to perform under the terms of these agreements, DTE Energy is required to perform on its behalf. Payments under these guarantees are considered remote.
Other Guarantees
In certain limited circumstances, the Registrants enter into contractual guarantees. The Registrants may guarantee another entity’s obligation in the event it fails to perform and may provide guarantees in certain indemnification agreements. Finally, the Registrants may provide indirect guarantees for the indebtedness of others. DTE Energy’s guarantees are not individually material with maximum potential payments totaling $56$64 million at December 31, 2015. Payment2018. Payments under these guarantees isare considered remote.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

DTE Energy is periodically required to obtain performance surety bonds in support of obligations to various governmental entities and other companies in connection with its operations. As of December 31, 2015,2018, DTE Energy had approximately $55$76 million of performance bonds outstanding. In the event that such bonds are called for nonperformance, DTE Energy would be obligated to reimburse the issuer of the performance bond. DTE Energy is released from the performance bonds as the contractual performance is completed and does not believe that a material amount of any currently outstanding performance bonds will be called.
Labor Contracts
There are several bargaining units for DTE Energy's approximately 4,900Energy subsidiaries' approximate 5,200 represented employees, including DTE Electric's approximately 2,600approximate 2,800 represented employees. The majority of the represented employees are under contracts that expire in 20162020 and 2017.2021.
Purchase Commitments
As of December 31, 2015,2018, the Registrants were party to numerous long-term purchase commitments relating to a variety of goods and services required for their businesses. These agreements primarily consist of fuel supply commitments and renewable energy contracts for the Registrants, as well as energy trading contracts for DTE Energy. The Registrants estimate the following commitments from 20162019 through 2051 for DTE Energy, and 20162019 through 20332039 for DTE Electric, as detailed in the following table:
 DTE Energy DTE Electric
 (In millions)
2016$2,038
 $493
20171,160
 412
2018611
 240
2019397
 120
2020353
 88
2021 and thereafter3,043
 992
 $7,602
 $2,345
 DTE Energy DTE Electric
 (In millions)
2019$2,691
 $777
20201,311
 541
2021632
 171
2022409
 88
2023351
 85
2024 and thereafter1,953
 737
 $7,347
 $2,399
DTE Energy and DTE Electric expect that 2016 annualUtility capital expenditures, expenditures for non-utility businesses, and contributions to equity method investees will be approximately $2.7$3.9 billion and $1.6$2.2 billion in 2019 for DTE Energy and DTE Electric, respectively. The Registrants have made certain commitments in connection with the estimated 20162019 annual capital expenditures and contributions to equity method investees.

Bankruptcies
111DTE Energy's Power and Industrial Projects segment holds ownership interests in, and operates, five generating plants that sell electric output from renewable sources under long-term power purchase agreements with PG&E. PG&E filed for Chapter 11 bankruptcy protection on January 29, 2019. As of December 31, 2018, uncollected pre-petition accounts receivable from PG&E were approximately $12 million. Currently, PG&E has been paying amounts owed in a timely manner and its account is current. As of December 31, 2018, DTE Energy has not recorded a reserve related to the pre-petition receivables.
As of December 31, 2018, the book value of long-lived assets used in producing electric output for sale to PG&E was approximately $106 million. As of December 31, 2018, DTE Energy performed an impairment analysis on its long-lived assets in accordance with ASC 360, Property, Plant and Equipment. Based on its undiscounted cash flow projections, DTE Energy determined that it did not have an impairment loss as of December 31, 2018. DTE Energy’s assumptions and conclusions may change, and it could have impairment losses if any of the terms of the contracts are not honored by PG&E or the contracts are rejected through the bankruptcy process.

The Power and Industrial Projects segment also has equity investments, including a note receivable, of approximately $77 million in entities that sell power to PG&E. DTE Energy has determined that it does not have an other than temporary decline in its equity investments as described in ASC 323, Investments-Equity Method and Joint Ventures. DTE Energy’s assumptions and conclusions may change in the future, and it could have an impairment loss if certain facilities are not utilized as currently anticipated or the contracts are rejected through the bankruptcy process.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Bankruptcies
Certain of the Registrants' customers and suppliers have filed for bankruptcy protection under the U.S. Bankruptcy Code. The Registrants regularly review contingent matters relating to these customers and suppliers and their purchase and sale contracts, and record provisions for amounts considered at risk of probable loss in the allowance for doubtful accounts. The Registrants believe their accrued amounts are adequate for probable loss.
Michigan Sales and Use Tax Litigation
In 2010, the Michigan Department of Treasury finalized a sales and use tax audit of DTE Electric for the period from January 2003 to September 2006. It determined that DTE Electric’s electric distribution equipment was not eligible for an industrial-processing exemption and therefore was subject to the use tax.  DTE Electric paid the tax for the period under audit and filed a claim in the Michigan Court of Claims disputing the tax determination.  DTE Electric has continued to apply an appropriate industrial-processing exemption percentage, where applicable, for purchases in the years subsequent to 2006.
The Michigan Court of Claims found in favor of DTE Electric, and that determination was subsequently appealed to the Michigan Supreme Court.  In July 2015, the Michigan Supreme Court issued an opinion finding that DTE Electric was eligible for a partial industrial-processing exemption on its electric distribution equipment based on the proportion of exempt use of that equipment. The Supreme Court reversed the lower court decision in part and remanded the case to the Michigan Court of Claims.  DTE Electric reached a settlement with the Michigan Department of Treasury in February 2016 and will receive a partial refund of amounts previously paid.
Other Contingencies
The Registrants are involved in certain other legal, regulatory, administrative, and environmental proceedings before various courts, arbitration panels, and governmental agencies concerning claims arising in the ordinary course of business. These proceedings include certain contract disputes, additional environmental reviews and investigations, audits, inquiries from various regulators, and pending judicial matters. The Registrants cannot predict the final disposition of such proceedings. The Registrants regularly review legal matters and record provisions for claims that they can estimate and are considered probable of loss. The resolution of these pending proceedings is not expected to have a material effect on the Registrants' Consolidated Financial Statements in the periods they are resolved.
For a discussion of contingencies related to regulatory matters and derivatives, see Notes 89 and 1213 to the Consolidated Financial Statements, "Regulatory Matters" and "Financial and Other Derivative Instruments",Instruments," respectively.

NOTE 1819 — NUCLEAR OPERATIONS
Property Insurance
DTE Electric maintains property insurance policies specifically for the Fermi 2 plant. These policies cover such items as replacement power and property damage. NEIL is the primary supplier of the insurance policies.
DTE Electric maintains a policy for extra expenses, including replacement power costs necessitated by Fermi 2’s unavailability due to an insured event. This policy has a 12-week waiting period and provides an aggregate $490 million of coverage over a three-year period.
DTE Electric has $1.5 billion in primary coverage and $1.25 billion of excess coverage for stabilization, decontamination, debris removal, repair and/or replacement of property, and decommissioning. The combined coverage limit for total property damage is $2.75 billion. The total limit for property damage for non-nuclear events is $2.0 billion and an aggregate of $328 million of coverage for extra expenses over a two-year period.
On January 13, 2015, the Terrorism Risk Insurance Program Reauthorization Act of 2015 was signed, extending TRIA through December 31, 2020. For multiple terrorism losses caused by acts of terrorism not covered under the TRIA occurring within one year after the first loss from terrorism, the NEIL policies would make available to all insured entities up to $3.2 billion, plus any amounts recovered from reinsurance, government indemnity, or other sources to cover losses.
Under NEIL policies, DTE Electric could be liable for maximum assessments of up to $41 million per event if the loss associated with any one event at any nuclear plant should exceed the accumulated funds available to NEIL.
Public Liability Insurance
As required by federal law, DTE Electric maintains $450 million of public liability insurance for a nuclear incident. For liabilities arising from a terrorist act outside the scope of TRIA, the policy is subject to one industry aggregate limit of $300 million. Further, under the Price-Anderson Amendments Act of 2005, deferred premium charges up to $138 million could be levied against each licensed nuclear facility, but not more than $20 million per year per facility. Thus, deferred premium charges could be levied against all owners of licensed nuclear facilities in the event of a nuclear incident at any of these facilities.
Nuclear Fuel Disposal Costs
In accordance with the Federal Nuclear Waste Policy Act of 1982, DTE Electric has a contract with the DOE for the future storage and disposal of spent nuclear fuel from Fermi 2 that required DTE Electric to pay the DOE a fee of 1 mill per kWh of Fermi 2 electricity generated and sold. The fee was a component of nuclear fuel expense. The 1 mill per kWh DOE fee was reduced to zero effective May 16, 2014.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The DOE's Yucca Mountain Nuclear Waste Repository program for the acceptance and disposal of spent nuclear fuel was terminated in 2011. DTE Electric is a party in the litigation against the DOE for both past and future costs associated with the DOE's failure to accept spent nuclear fuel under the timetable set forth in the Federal Nuclear Waste Policy Act of 1982. In July 2012, DTE Electric executed a settlement agreement with the federal government for costs associated with the DOE's delay in acceptance of spent nuclear fuel from Fermi 2 for permanent storage. The settlement agreement, including extensions, provides for a claims process and payment of delay-related costs experienced by DTE Electric through 2019. DTE Electric's claims are being settled and paid on a timely basis. The settlement proceeds reduce the cost of the dry cask storage facility assets and provide reimbursement for related operating expenses.
DTE Electric currently employs a spent nuclear fuel storage strategy utilizing a fuel pool and a dry cask storage facility. The spent nuclear fuel storage strategy is expected to provide sufficient spent fuel storage capability for the life of the plant as defined by the original operating license.
The federal government continues to maintain its legal obligation to accept spent nuclear fuel from Fermi 2 for permanent storage. Issues relating to long-term waste disposal policy and to the disposition of funds contributed by DTE Electric ratepayers to the federal waste fund await future governmental action.

NOTE 20 — RETIREMENT BENEFITS AND TRUSTEED ASSETS
DTE Energy's subsidiary, DTE Energy Corporate Services, LLC (LLC), sponsors defined benefit pension plans and other postretirement plans covering certain employees of the Registrants.
The table below represents the pension and other postretirement benefit plans of each Registrant at December 31, 2018:
Registrants
DTE EnergyDTE Electric
Qualified Pension Plans
DTE Energy Company Retirement PlanXX
DTE Gas Company Retirement Plan for Employees Covered by Collective Bargaining AgreementsX
Shenango Inc. Pension PlanX
Nonqualified Pension Plans
DTE Energy Company Supplemental Retirement PlanXX
DTE Energy Company Executive Supplemental Retirement Plan(a)
XX
DTE Energy Company Supplemental Severance Benefit PlanX
Other Postretirement Benefit Plans
The DTE Energy Company Comprehensive Non-Health Welfare PlanXX
The DTE Energy Company Comprehensive Retiree Group Health Care PlanXX
DTE Supplemental Retiree Benefit PlanXX
DTE Energy Company Retiree Reimbursement Arrangement PlanXX

(a)Sponsored by the DTE Energy subsidiary, DTE Energy Holding Company.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

DTE Electric participates in various plans that provide pension and other postretirement benefits for DTE Energy and its affiliates. The plans are sponsored by the LLC. DTE Electric accounts for its participation in DTE Energy's qualified and nonqualified pension plans by applying multiemployer accounting. DTE Electric accounts for its participation in other postretirement benefit plans by applying multiple-employer accounting. Within multiemployer and multiple-employer plans, participants pool plan assets for investment purposes and to reduce the cost of plan administration. The primary difference between plan types is assets contributed in multiemployer plans can be used to provide benefits for all participating employers, while assets contributed within a multiple-employer plan are restricted for use by the contributing employer. As a result of multiemployer accounting treatment, capitalized costs associated with these plans are reflected in Property, plant, and equipment in DTE Electric's Consolidated Statements of Financial Position. The same capitalized costs are reflected as Regulatory assets and liabilities in DTE Energy's Consolidated Statements of Financial Position. In addition, the service cost and non-service cost components are presented in Operation and maintenance in DTE Electric's Consolidated Statements of Operations. The same non-service cost components are presented in Other (Income) and Deductions — Non-operating retirement benefits, net in DTE Energy's Consolidated Statements of Operations. Plan participants of all plans are solely DTE Energy and affiliate participants.
Pension Plan Benefits
DTE Energy has qualified defined benefit retirement plans for eligible represented and non-represented employees. The plans are noncontributory and provide traditional retirement benefits based on the employees’employee's years of benefit service, average final compensation, and age at retirement. In addition, certain represented and non-represented employees are covered under cash balance provisions that determine benefits on annual employer contributions and interest credits. DTE Energy also maintains supplemental nonqualified, noncontributory, retirement benefit plans for selectedcertain management employees. These plans provide for benefits that supplement those provided by DTE Energy’s other retirement plans.
DTE Electric participates in various plans that provideNet pension and other postretirement benefitscost for DTE Energy and its affiliates. The plans are sponsored by DTE Energy Corporate Services, LLC (LLC), a subsidiary of DTE Energy. DTE Electric is allocated net periodic benefit costs for its share ofincludes the amounts of the combined plans.following components:
Effective January 1, 2012 for the Registrants' non-represented employees, and in June 2011 for certain DTE Energy represented employees and March 2013 for the majority of DTE Electric represented employees, the Registrants discontinued offering a defined benefit retirement plan to newly hired employees. In its place, the Registrants will annually contribute an amount equivalent to 4% (8% for certain DTE Gas represented employees) of an employee's eligible pay to the employee's defined contribution retirement savings plan.

 2018 2017 2016
 (In millions)
Service cost$99
 $92
 $92
Interest cost202
 214
 219
Expected return on plan assets(329) (311) (309)
Amortization of:     
Net actuarial loss176
 176
 164
Prior service cost
 1
 1
Net pension cost$148
 $172
 $167
112

 2018 2017
 (In millions)
Other changes in plan assets and benefit obligations recognized in Regulatory assets and Other comprehensive income (loss)   
Net actuarial loss$125
 $27
Amortization of net actuarial loss(176) (176)
Prior service credit
 (11)
Amortization of prior service cost
 (1)
Total recognized in Regulatory assets and Other comprehensive income (loss)$(51) $(161)
Total recognized in net periodic pension cost, Regulatory assets, and Other comprehensive income (loss)$97
 $11
Estimated amounts to be amortized from Regulatory assets and Accumulated other comprehensive income (loss) into net periodic benefit cost during next fiscal year   
Net actuarial loss$131
 $178
Prior service cost$1
 $

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following table reconciles the obligations, assets, and funded status of the plans as well as the amounts recognized as prepaid pension cost or pension liability in DTE Energy's Consolidated Statements of Financial Position at December 31:
 DTE Energy
 2018 2017
 (In millions)
Accumulated benefit obligation, end of year$4,779
 $5,149
Change in projected benefit obligation   
Projected benefit obligation, beginning of year$5,576
 $5,171
Service cost99
 92
Interest cost202
 214
Plan amendments
 (11)
Actuarial (gain) loss(438) 391
Benefits paid(315) (281)
Projected benefit obligation, end of year$5,124
 $5,576
Change in plan assets   
Plan assets at fair value, beginning of year$4,636
 $4,012
Actual return on plan assets(233) 674
Company contributions185
 231
Benefits paid(315) (281)
Plan assets at fair value, end of year$4,273
 $4,636
Funded status$(851) $(940)
Amount recorded as:   
Current liabilities$(14) $(16)
Noncurrent liabilities(837) (924)
 $(851) $(940)
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax   
Net actuarial loss$152
 $163
Prior service cost5
 6
 $157
 $169
Amounts recognized in Regulatory assets(a)
   
Net actuarial loss$1,973
 $2,014
Prior service credit(12) (14)
 $1,961
 $2,000

(a)See Note 9 to the Consolidated Financial Statements, "Regulatory Matters."
The Registrants' policy is to fund pension costs by contributing amounts consistent with the provisions of the Pension Protection Act of 2006, and additional amounts when it deems appropriate. DTE Energy contributed $177 million, including $145 million of DTE ElectricThe following table provides contributions to the qualified pension plans in 2015. At the discretion of management, and depending upon financial market conditions, DTE Energy anticipates making up to $180 million in contributions, including $145 million of DTE Electric contributions, to the pension plans in 2016.
Net pension cost for DTE Energy includes the following components:
 2015 2014 2013
 (In millions)
Service cost$100
 $83
 $94
Interest cost210
 212
 192
Expected return on plan assets(296) (273) (266)
Amortization of net actuarial loss205
 157
 208
Special termination benefits2
 
 
Net pension cost$221
 $179
 $228
 2015 2014
 (In millions)
Other changes in plan assets and benefit obligations recognized in Regulatory assets and Other comprehensive income (loss)   
Net actuarial loss$19
 $805
Amortization of net actuarial loss(205) (157)
Prior service credit
 (7)
Total recognized in Regulatory assets and Other comprehensive income (loss)$(186) $641
Total recognized in net periodic pension cost, Regulatory assets, and Other comprehensive income (loss)$35
 $820
Estimated amounts to be amortized from Regulatory assets and Accumulated other comprehensive income (loss) into net periodic benefit cost during next fiscal year   
Net actuarial loss$162
 $206
Net pension cost for DTE Electric includes the following components:in:
 2015 2014 2013
 (In millions)
Service cost$77
 $64
 $73
Interest cost160
 162
 146
Expected return on plan assets(210) (194) (184)
Amortization of:     
Net actuarial loss147
 110
 148
Prior service cost1
 2
 1
Special termination benefits1
 
 
Net pension cost$176
 $144
 $184
 2018 2017 2016
 (In millions)
DTE Energy$175
 $223
 $179
DTE Electric175
 185
 145

113


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

 2015 2014
 (In millions)
Other changes in plan assets and benefit obligations recognized in Regulatory assets and Other comprehensive income (loss)   
Net actuarial (gain) loss$(13) $614
Amortization of net actuarial loss(147) (110)
Prior service credit
 (2)
Amortization of prior service cost(1) (2)
Total recognized in Regulatory assets and Other comprehensive income (loss)$(161) $500
Total recognized in net periodic pension cost, Regulatory assets, and Other comprehensive income (loss)$15
 $644
Estimated amounts to be amortized from Regulatory assets and Accumulated other comprehensive income (loss) into net periodic benefit cost during next fiscal year   
Net actuarial loss$115
 $149
Prior service cost$1
 $1
TheDuring 2018, DTE Energy contributed the following table reconcilesamounts of DTE Energy common stock to the obligations, assets, and funded status of the plans as well as the amounts recognized as prepaid pension cost or pension liability in the Registrants' Consolidated Statements of Financial Position at December 31:DTE Energy Company Affiliates Employee Benefit Plans Master Trust:
 DTE Energy DTE Electric
 2015 2014 2015 2014
 (In millions)
Accumulated benefit obligation, end of year$4,569
 $4,853
 $3,401
 $3,712
Change in projected benefit obligation       
Projected benefit obligation, beginning of year$5,269
 $4,380
 $4,018
 $3,341
Service cost100
 83
 75
 64
Interest cost210
 212
 156
 162
Plan amendments
 (7) 
 (2)
Actuarial (gain) loss(357) 836
 (273) 634
Transfer due to plan sponsorship change
 
 (99) 
Special termination benefits2
 
 
 
Benefits paid(253) (235) (192) (181)
Projected benefit obligation, end of year$4,971
 $5,269
 $3,685
 $4,018
Change in plan assets       
Plan assets at fair value, beginning of year$3,981
 $3,720
 $2,812
 $2,632
Actual return on plan assets(79) 301
 (56) 212
Company contributions183
 195
 145
 149
Benefits paid(253) (235) (192) (181)
Plan assets at fair value, end of year$3,832
 $3,981
 $2,709
 $2,812
Funded status of the plans$(1,139) $(1,288) $(976) $(1,206)
Amount recorded as:       
Current liabilities$(6) $(8) $
 $(6)
Noncurrent liabilities(1,133) (1,280) (976) (1,200)
 $(1,139) $(1,288) $(976) $(1,206)
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax       
Net actuarial loss$180
 $194
 $
 $44
Prior service credit(1) (1) 
 
 $179
 $193
 $
 $44
Amounts recognized in Regulatory assets (see Note 8 - "Regulatory Matters")       
Net actuarial loss$2,113
 $2,285
 $1,588
 $1,738
Prior service cost (credit)(1) (1) 4
 5
 $2,112
 $2,284
 $1,592
 $1,743
Date Number of Shares Price per Share Amount
      (In millions)
March 7, 2018 1,751,401 $99.92 $175

The above contribution was made on behalf of DTE Electric, for which DTE Electric paid DTE Energy cash consideration of $175 million in March 2018.
114


At the discretion of management, and depending upon financial market conditions, DTE Energy anticipates making up to $150 million in contributions, including $100 million of DTE Electric contributions, to the qualified pension plans in 2019.
DTE Energy Company —Energy's subsidiaries are responsible for their share of qualified and nonqualified pension benefit costs. DTE Electric CompanyElectric's allocated portion of pension benefit costs included in capital expenditures and operating and maintenance expense were $120 million for the year ended December 31, 2018 and $136 million for the years ended December 31, 2017 and 2016. These amounts include recognized contractual termination benefit charges, curtailment gains, and settlement charges.
Combined Notes to Consolidated Financial Statements — (Continued)

At December 31, 2015,2018, the benefits related to the Registrants'DTE Energy's qualified and nonqualified pension plans expected to be paid in each of the next five years and in the aggregate for the five fiscal years thereafter are as follows:
 DTE Energy DTE Electric
 (In millions)
2016$274
 $213
2017285
 221
2018297
 231
2019306
 238
2020314
 244
2021-20251,662
 1,279
Total$3,138
 $2,426
 (In millions)
2019$311
2020317
2021317
2022323
2023332
2024-20281,713
Total$3,313
Assumptions used in determining the projected benefit obligation and net pension costs of the RegistrantsDTE Energy are:
2015 2014 20132018 2017 2016
Projected benefit obligation  
Discount rate4.50% 4.12% 4.95%4.40% 3.70% 4.25%
Rate of compensation increase4.65% 4.65% 4.20%4.98% 4.98% 4.65%
Net pension costs  
Discount rate4.12% 4.95% 4.15%3.70% 4.25% 4.50%
Rate of compensation increase4.65% 4.20% 4.20%4.98% 4.65% 4.65%
Expected long-term rate of return on plan assets7.75% 7.75% 8.25%7.50% 7.50% 7.75%
The Registrants employDTE Energy employs a formal process in determining the long-term rate of return for various asset classes. Management reviews historic financial market risks and returns and long-term historic relationships between the asset classes of equities, fixed income, and other assets, consistent with the widely accepted capital market principle that asset classes with higher volatility generate a greater return over the long-term. Current market factors such as inflation, interest rates, asset class risks, and asset class returns are evaluated and considered before long-term capital market assumptions are determined. The long-term portfolio return is also established employing a consistent formal process, with due consideration of diversification, active investment management, and rebalancing. Peer data is reviewed to check for reasonableness. As a result of this process, the Registrants have long-term rate of return assumptions for the pension plans of 7.75%7.30% and other postretirement benefit plans of 8.00%7.75% for 2016.2019. The Registrants believe these rates are a reasonable assumption for the long-term rate of return on plan assets for 20162019 given the current investment strategy.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The Registrants employDTE Energy Company Affiliates Employee Benefit Plans Master Trust employs a total returnliability driven investment approachprogram whereby a mixthe characteristics of equities, fixed income, and other investmentsplan liabilities are used to maximize the long-term return on plan assets consistent with prudent levels of risk, with consideration given to the liquidity needs of the plan.considered when determining investment policy. Risk tolerance is established through consideration of future plan cash flows, plan funded status, and corporate financial considerations. The investment portfolio contains a diversified blend of equity, fixed income, and other investments. Furthermore, equity investments are diversified across U.S. and non-U.S. stocks growth and value stocks, and large and small market capitalizations. Fixed income securitiesinvestments generally include market durationU.S. Treasuries, other governmental debt, diversified corporate bonds, of companies from diversified industries, mortgage-backed securities, non-U.S. securities, bank loans, and U.S. Treasuries. Pension assets include long duration U.S. government and diversified corporate bonds intended to partially mitigate liability volatility caused by changes in discount rates.mortgage-backed securities. Other assets, such as private markets and hedge funds,investments are used to enhance long-term returns while improving portfolio diversification. Derivatives may be utilized in a risk controlled manner, to potentially increase the portfolio beyond the market value of invested assets and/or reduce portfolio investment risk. Investment risk is measured and monitored on an ongoing basis through annual liability measurements, periodic asset/liability studies, and quarterly investment portfolio reviews.

115


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Target allocations for the Registrants'DTE Energy's pension plan assets as of December 31, 20152018 are listed below:
U.S. Large Capitalization (Cap) Equity Securities2216%
U.S. Small Cap and Mid Cap Equity Securities54
Non-U.S. Equity Securities2015
Fixed Income Securities2542
Hedge Funds and Similar Investments2015
Private Equity and Other8
 100%

116


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following tables provide the fair value measurement amounts for the Registrants'DTE Energy's pension plan assets at December 31, 20152018 and 2014 2017(a):
December 31, 2015 December 31, 2014December 31, 2018 December 31, 2017
Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 TotalLevel 1 Level 2 
Other(b)
 Total Level 1 Level 2 
Other(b)
 Total
(In millions)(In millions)
DTE Energy asset category:                              
Short-term Investments (b)(c)$23
 $
 $
 $23
 $46
 $
 $
 $46
$
 $27
 $
 $27
 $
 $114
 $
 $114
Equity Securities 
  
  
    
  
  
 

              

U.S. Large Cap (c)(d)842
 
 
 842
 899
 
 
 899
606
 3
 
 609
 821
 5
 
 826
U.S. Small Cap and Mid Cap (d)(e)219
 
 
 219
 225
 
 
 225
123
 1
 
 124
 229
 5
 
 234
Non-U.S. (e)(f)510
 251
 
 761
 526
 219
 
 745
337
 9
 240
 586
 529
 13
 280
 822
Fixed Income Securities (f)(g)5
 1,024
 
 1,029
 7
 1,113
 
 1,120
6
 1,892
 
 1,898
 1
 1,453
 
 1,454
Hedge Funds and Similar Investments (g)(h)220
 96
 452
 768
 226
 95
 438
 759
88
 
 542
 630
 265
 
 593
 858
Private Equity and Other (h)(i)
 
 190
 190
 
 
 187
 187

 
 399
 399
 
 
 328
 328
Securities Lending (i)(j)(129) (25) 
 (154) (189) (50) 
 (239)(22) (8) 
 (30) (53) (13) 
 (66)
Securities Lending Collateral (i)(j)129
 25
 
 154
 189
 50
 
 239
22
 8
 
 30
 53
 13
 
 66
DTE Energy Total$1,819
 $1,371
 $642
 $3,832
 $1,929
 $1,427
 $625
 $3,981
$1,160
 $1,932
 $1,181
 $4,273
 $1,845
 $1,590
 $1,201
 $4,636
               
DTE Electric asset category:               
Short-term Investments (b)$16
 $
 $
 $16
 $33
 $
 $
 $33
Equity Securities 
  
  
    
  
  
  
U.S. Large Cap (c)599
 
 
 599
 638
 
 
 638
U.S. Small Cap and Mid Cap (d)157
 
 
 157
 162
 
 
 162
Non-U.S. (e)367
 178
 
 545
 378
 157
 
 535
Fixed Income Securities (f)4
 699
 
 703
 5
 758
 
 763
Hedge Funds and Similar Investments (g)158
 69
 325
 552
 163
 68
 315
 546
Private Equity and Other (h)
 
 137
 137
 
 
 135
 135
Securities Lending (i)(93) (18) 
 (111) (136) (36) 
 (172)
Securities Lending Collateral (i)93
 18
 
 111
 136
 36
 
 172
DTE Electric Total$1,301
 $946
 $462
 $2,709
 $1,379
 $983
 $450
 $2,812

(a)For a description of levels within the fair value hierarchy, see Note 1112 to the Consolidated Financial Statements, "Fair Value".Value."
(b)Amounts represent assets valued at NAV as a practical expedient for fair value.
(c)This category predominantly represents certain short-term fixed income securities and money market investments that are managed in separate accounts or commingled funds. Pricing for investments in this category are obtained from quoted prices in actively traded markets or valuations from brokers or pricing services.
(c)(d)This category comprises both actively and not actively managedrepresents portfolios that track the S&P 500 low cost equity index funds.of large capitalization domestic equities. Investments in this category are exchange-traded securities whereby unadjusted quotequoted prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
(d)(e)This category represents portfolios of small and medium capitalization domestic equities. Investments in this category are exchange-traded securities whereby unadjusted quotequoted prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
(e)(f)This category primarily consists of portfolios of non-U.S. developed and emerging market equities. Investments in this category are exchange-traded securities whereby unadjusted quotequoted prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2NAV assets.
(f)(g)This category includes corporate bonds from diversified industries, U.S. Treasuries, other governmental debt, bank loans, and mortgage-backed securities. Pricing for investments in this category is obtained from quoted prices in actively traded markets and quotations from broker or pricing services. Non-exchange traded securities and exchange-traded securities held in commingled funds are classified as Level 2 assets.
(g)(h)This category utilizes a diversified group of strategies that attempt to capture financial market inefficiencies and includes publicly traded debt and equity, publicly traded mutual funds, commingled funds and limited partnership funds, and non-exchange traded securities.funds. Pricing for Level 1 and Level 2 assetsmutual funds in this category is obtained from quoted prices in actively traded marketsmarkets. Commingled funds and quoted prices from broker or pricing services. Non-exchange traded securities held in commingledlimited partnership funds are classified as Level 2NAV assets. Valuations for some Level 3 assets in this category may be based on limited observable inputs as there may be little, if any, publicly available pricing.
(h)(i)This category includes a diversified group of funds and strategies that primarily invests in private equity partnerships. This category also includes investments in timberreal estate and private mezzanine debt. PricingAll pricing for investments in this category is based on limited observable inputsare classified as there is little, if any, publicly available pricing. Valuations for assets in this category may be based on discounted cash flow analyses, relevant publicly-traded comparables, and comparable transactions.NAV assets.
(i)(j)In 2014, the Registrants beganDTE Energy has a securities lending program with a third-party agent. The program allows the agent to lend certain securities from the Registrants'DTE Energy's pension truststrust to selected entities against receipt of collateral (in the form of cash) as provided for and determined in accordance with their securities lending agency agreements.

117


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The pension trust holds debt and equity securities directly and indirectly through commingled funds and institutional mutual funds. Exchange-traded debt and equity securities held directly are valued using quoted market prices in actively traded markets. The commingled funds and institutional mutual funds hold exchange-traded equity or debt securities and are valued based on stated NAVs. Non-exchange traded fixed income securities are valued by the trustee based upon quotations available from brokers or pricing services. A primary price source is identified by asset type, class, or issue for each security. The trustee monitors prices supplied by pricing services and may use a supplemental price source or change the primary price source of a given security if the trustee challenges an assigned price and determines that another price source is considered to be preferable. The Registrants haveDTE Energy has obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Additionally, the Registrants selectively corroborate the fair values of securities by comparison of market-based price sources.
The following table provides a reconciliation of beginning and ending balances of DTE Energy's pension plan assets measured at fair value on a recurring basis where the determination of fair value includes significant unobservable inputs (Level 3):
 Year Ended December 31, 2015 Year Ended December 31, 2014
 Hedge Funds
and Similar
Investments
 Private Equity
and Other
 Total Hedge Funds
and Similar
Investments
 Private Equity
and Other
 Total
 (In millions)
Beginning Balance at January 1$438
 $187
 $625
 $395
 $170
 $565
Total realized/unrealized gains (losses)10
 10
 20
 22
 16
 38
Purchases, sales, and settlements:           
Purchases4
 32
 36
 22
 31
 53
Sales
 (39) (39) (1) (30) (31)
Ending Balance at December 31$452
 $190
 $642
 $438
 $187
 $625
The amount of total gains for the period attributable to the change in unrealized gains or losses related to assets still held at the end of the period$10
 $(3) $7
 $21
 $11
 $32
The following table provides a reconciliation of beginning and ending balances of DTE Electric's pension plan assets measured at fair value on a recurring basis where the determination of fair value includes significant unobservable inputs (Level 3):
 Year Ended December 31, 2015 Year Ended December 31, 2014
 Hedge Funds
and Similar
Investments
 Private Equity
and Other
 Total Hedge Funds
and Similar
Investments
 Private Equity
and Other
 Total
 (In millions)
Beginning Balance at January 1$315
 $135
 $450
 $285
 $122
 407
Total realized/unrealized gains (losses)7
 7
 14
 15
 12
 27
Purchases, sales, and settlements:           
Purchases3
 23
 26
 16
 22
 38
Sales
 (28) (28) (1) (21) (22)
Ending Balance at December 31$325
 $137
 $462
 $315
 $135
 $450
The amount of total gains for the period attributable to the change in unrealized gains or losses related to assets still held at the end of the period$7
 $(2) $5
 $15
 $8
 $23
There were no transfers from or into Level 3 and there were no significant transfers between Level 2 and Level 1 in the years ended December 31, 20152018 and 20142017 for either of the Registrants.

118


DTE Energy Company — DTE Electric CompanyEnergy.
Combined Notes to Consolidated Financial Statements — (Continued)

Other Postretirement Benefits
The Registrants participate in defined benefit plans sponsored by the LLC that provide certain other postretirement health care and life insurance benefits for employees who are eligible for these benefits. The Registrants' policy is to fund certain trusts to meet its other postretirement benefit obligations. Separate qualified VEBA and other benefit trusts exist. DTE Energy contributed $199 milliondid not make any contributions to these trusts including $175 million of DTE Electricduring 2018 and does not anticipate making any contributions for the defined benefit other postretirement medical and life insurance benefit plans during 2015. At the discretion of management, DTE Energy anticipates making up to $20 million of contributions, through contributions from DTE Gas, to the trusts in 2016.2019.
Starting in 2012,

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

DTE Energy and DTE Electric offer a defined contribution VEBA for eligible represented and non-represented employees, in lieu of offering future employees defined benefit post-employment health care and life insurance benefits, thebenefits. The Registrants allocate a fixed amount per year to an account in a defined contribution VEBA for each employee. These accounts are managed either by the Registrant (for non-represented and certain represented groups) or by the Utility Workers of America (UWUA) for Local 223 employees. DTE Energy contributions to the VEBA for these accounts were $5$11 million in 2015, $42018, $8 million in 2014,2017, and $2$6 million in 2013,2016, including DTE Electric contributions of $3$5 million in 2015, $2 million in 2014,2018, 2017, and $1 million in 2013.2016.
Beginning in 2013, theThe Registrants replaced the defined benefit employer-sponsored retiree medical, prescription drug, and dental coverage withalso contribute a notional allocationfixed amount to a Retiree Reimbursement Account. This change applies to both current and future Medicare eligibleAccount, for certain non-represented and future represented retirees, spouses, and surviving spouses or same sex domestic partners when the youngest of the retiree's covered household turns age 65.becomes eligible for Medicare Part A based on age. The amount of the annual allocation to each participant is determined by the employee's retirement date, and increases each year for each eligible participant at the lower of the rate of medical inflation or 2%.
Net other postretirement credit for DTE Energy includes the following components:
2015 2014 20132018 2017 2016
(In millions)(In millions)
Service cost$34
 $34
 $47
$27
 $27
 $27
Interest cost81
 89
 88
69
 73
 80
Expected return on plan assets(131) (122) (110)(143) (130) (129)
Amortization of: 
  
  
     
Net actuarial loss43
 20
 64
11
 13
 30
Prior service credit(126) (144) (131)
 (14) (118)
Other
 
 (1)
Net other postretirement credit$(99) $(123) $(42)$(36) $(31) $(111)
2015 20142018 2017
(In millions)(In millions)
Other changes in plan assets and accumulated postretirement benefit obligation recognized in Regulatory assets and Other comprehensive income (loss)      
Net actuarial (gain) loss$(68) $192
Net actuarial gain$(8) $(21)
Amortization of net actuarial loss(43) (20)(11) (13)
Prior service credit(44) (1)
Amortization of prior service credit126
 144

 14
Total recognized in Regulatory assets and Other comprehensive income (loss)$15
 $316
$(63) $(21)
Total recognized in net periodic benefit cost, Regulatory assets, and Other comprehensive income (loss)$(84) $193
$(99) $(52)
Estimated amounts to be amortized from Regulatory assets and Accumulated other comprehensive income (loss) into net periodic benefit cost during next fiscal year      
Net actuarial loss$32
 $43
$12
 $11
Prior service credit$(118) $(126)$(9) $(1)

Net other postretirement credit for DTE Electric includes the following components:
119

 2018 2017 2016
 (In millions)
Service cost$20
 $20
 $20
Interest cost53
 56
 61
Expected return on plan assets(98) (90) (90)
Amortization of:     
Net actuarial loss8
 8
 21
Prior service credit
 (10) (89)
Net other postretirement credit$(17) $(16) $(77)

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Net other postretirement credit for DTE Electric includes the following components:
 2015 2014 2013
 (In millions)
Service cost$25
 $26
 $35
Interest cost62
 68
 67
Expected return on plan assets(90) (85) (74)
Amortization of:     
Net actuarial loss31
 14
 47
Prior service credit(95) (109) (100)
Net other postretirement credit$(67) $(86) $(25)
 2018 2017
 (In millions)
Other changes in plan assets and accumulated postretirement benefit obligation recognized in Regulatory assets   
Net actuarial (gain) loss$(46) $2
Amortization of net actuarial loss(8) (8)
Amortization of prior service (cost) credit(35) 10
Total recognized in Regulatory assets$(89) $4
Total recognized in net periodic benefit cost and Regulatory assets$(106) $(12)
Estimated amounts to be amortized from Regulatory assets into net periodic benefit cost during next fiscal year   
Net actuarial loss$5
 $8
Prior service credit$(7) $
 2015 2014
 (In millions)
Other changes in plan assets and accumulated postretirement benefit obligation recognized in Regulatory assets and Other comprehensive income (loss)   
Net actuarial (gain) loss$(57) $144
Amortization of net actuarial loss(31) (14)
Amortization of prior service credit95
 109
Total recognized in Regulatory assets and Other comprehensive income (loss)$7
 $239
Total recognized in net periodic benefit cost, Regulatory assets, and Other comprehensive income (loss)$(60) $153
Estimated amounts to be amortized from Regulatory assets and Accumulated other comprehensive income (loss) into net periodic benefit cost during next fiscal year   
Net actuarial loss$22
 $31
Prior service credit$(89) $(94)

120


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following table reconciles the obligations, assets, and funded status of the plans including amounts recorded as Accrued postretirement liability in the Registrants' Consolidated Statements of Financial Position at December 31:
 DTE Energy DTE Electric
 2018 2017 2018 2017
 (In millions)
Change in accumulated postretirement benefit obligation       
Accumulated postretirement benefit obligation, beginning of year$1,910
 $1,795
 $1,470
 $1,373
Service cost27
 27
 20
 20
Interest cost69
 73
 53
 56
Plan amendments(44) 
 (35) 
Actuarial (gain) loss(227) 101
 (196) 84
Benefits paid(90) (86) (65) (63)
Accumulated postretirement benefit obligation, end of year$1,645
 $1,910
 $1,247
 $1,470
Change in plan assets       
Plan assets at fair value, beginning of year$1,848
 $1,758
 $1,272
 $1,218
Actual return on plan assets(75) 252
 (52) 172
Benefits paid(84) (162) (62) (118)
Plan assets at fair value, end of year$1,689
 $1,848
 $1,158
 $1,272
Funded status$44
 $(62) $(89) $(198)
Amount recorded as:       
Noncurrent assets$45
 $
 $189
 $113
Current liabilities(1) (1) 
 
Noncurrent liabilities
 (61) (278) (311)
 $44
 $(62) $(89) $(198)
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax       
Net actuarial (gain) loss$1
 $(1) $
 $
 $1
 $(1) $
 $
Amounts recognized in Regulatory assets(a)
       
Net actuarial loss$257
 $279
 $156
 $211
Prior service credit(44) (1) (35) 
 $213
 $278
 $121
 $211

(a)See Note 9 to the Consolidated Financial Statements, "Regulatory Matters."

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)
 DTE Energy DTE Electric
 2015 2014 2015 2014
 (In millions)
Change in accumulated postretirement benefit obligation       
Accumulated postretirement benefit obligation, beginning of year$2,044
 $1,878
 $1,558
 $1,430
Service cost34
 34
 25
 26
Interest cost81
 89
 62
 68
Actuarial (gain) loss(224) 131
 (166) 100
Benefits paid(89) (88) (65) (66)
Accumulated postretirement benefit obligation, end of year$1,846
 $2,044
 $1,414
 $1,558
Change in plan assets       
Plan assets at fair value, beginning of year$1,528
 $1,527
 $1,038
 $1,061
Actual return on plan assets(25) 62
 (19) 41
Company contributions199
 24
 175
 
Benefits paid(85) (85) (63) (64)
Plan assets at fair value, end of year$1,617
 $1,528
 $1,131
 $1,038
Funded status, end of year$(229) $(516) $(283) $(520)
Amount recorded as:       
Noncurrent assets$
 $
 $24
 $
Current liabilities(1) (1) 
 
Noncurrent liabilities(228) (515) (307) (520)
 $(229) $(516) $(283) $(520)
Amounts recognized in Accumulated other comprehensive income (loss), pre-tax       
Net actuarial loss$24
 $34
 $
 $
Prior service credit(2) (5) 
 
 $22
 $29
 $
 $
Amounts recognized in Regulatory assets (see Note 8 - "Regulatory Matters")       
Net actuarial loss$387
 $488
 $297
 $385
Prior service credit(131) (254) (99) (194)
 $256
 $234
 $198
 $191

At December 31, 2015,2018, the benefits expected to be paid, including prescription drug benefits, in each of the next five years and in the aggregate for the five fiscal years thereafter for the Registrants are as follows:
 DTE Energy DTE Electric
 (In millions)
2016$100
 $77
2017105
 81
2018108
 84
2019113
 88
2020116
 90
2021-2025621
 476
Total$1,163
 $896
 DTE Energy DTE Electric
 (In millions)
2019$88
 $66
202092
 70
202196
 73
2022100
 75
2023102
 77
2024-2028532
 402
Total$1,010
 $763

121


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Assumptions used in determining the accumulated postretirement benefit obligation and net other postretirement benefit costs of the Registrants are:
2015 2014 20132018 2017 2016
Accumulated postretirement benefit obligation  
Discount rate4.50% 4.10% 4.95%4.40% 3.70% 4.25%
Health care trend rate pre- and post- 656.25 / 6.75% 7.50 / 6.50% 7.50 / 6.50%6.75 / 7.25% 6.75 / 7.25% 6.50 / 6.75%
Ultimate health care trend rate4.50% 4.50% 4.50%4.50% 4.50% 4.50%
Year in which ultimate reached pre- and post- 652027 2025 / 2024 2025 / 20242031 2030 2028
Other postretirement benefit costs  
Discount rate (prior to interim remeasurement)4.10% 4.95% 4.15%
Discount rate (post interim remeasurement)N/A N/A 4.30%
Discount rate3.70% 4.25% 4.50%
Expected long-term rate of return on plan assets8.00% 8.00% 8.25%7.75% 7.75% 8.00%
Health care trend rate pre- and post- 657.50 / 6.50% 7.50 / 6.50% 7.00%6.75 / 7.25% 6.50 / 6.75% 6.25 / 6.75%
Ultimate health care trend rate4.50% 4.50% 5.00%4.50% 4.50% 4.50%
Year in which ultimate reached pre- and post- 652025 / 2024 2025 / 2024 20212030 2028 2027
A one percentage point increase in health care cost trend rates would have increased the total service cost and interest cost components of benefit costs for DTE Energy by $6$4 million, including $4$3 million for DTE Electric, in 20152018 and would have increased the accumulated benefit obligation for DTE Energy by $100$72 million, including $74$51 million for DTE Electric, at December 31, 2015.2018. A one percentage point decrease in the health care cost trend rates would have decreased the total service and interest cost components of benefit costs for DTE Energy by $5$4 million, including $4$3 million for DTE Electric, in 20152018 and would have decreased the accumulated benefit obligation for DTE Energy by $86$63 million, including $64$45 million for DTE Electric, at December 31, 2015.2018.
The process used in determining the long-term rate of return foron assets and the investment approach for the other postretirement benefit plans is similar to thosethat previously described for the pension plans.
The DTE Energy Master VEBA Trust employs a total return investment approach. The investment portfolio contains a diversified blend of equity, fixed income, and other investments. Furthermore, equity investments are diversified across U.S. and non-U.S. stocks and large and small market capitalizations. Fixed income investments generally include U.S. Treasuries, other governmental debt, diversified corporate bonds, bank loans, and mortgage-backed securities. Other investments are used to enhance long-term returns while improving portfolio diversification. Derivatives may be utilized in a risk controlled manner to potentially increase the portfolio beyond the market value of invested assets and/or reduce portfolio investment risk. Investment risk is measured and monitored on an ongoing basis through annual liability measurements, periodic asset/liability studies, and quarterly investment portfolio reviews.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Target allocations for the Registrants' other postretirement benefit plan assets as of December 31, 20152018 are listed below:
U.S. Large Cap Equity Securities1716%
U.S. Small Cap and Mid Cap Equity Securities4
Non-U.S. Equity Securities2019
Fixed Income Securities2528
Hedge Funds and Similar Investments2019
Private Equity and Other14
 100%

122


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following tables provide the fair value measurement amounts for the Registrants' other postretirement benefit plan assets at December 31, 20152018 and 2014 2017(a):
December 31, 2015 December 31, 2014December 31, 2018 December 31, 2017
Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 TotalLevel 1 Level 2 
Other(b)
 Total Level 1 Level 2 
Other(b)
 Total
DTE Energy asset category:(In millions)(In millions)
Short-term Investments (b)(c)$7
 $
 $
 $7
 $6
 $
 $
 $6
$14
 $2
 $
 $16
 $13
 $2
 $
 $15
Equity Securities 
  
  
    
  
  
                 
U.S. Large Cap (c)(d)264
 
 
 264
 266
 
 
 266
225
 
 
 225
 284
 
 
 284
U.S. Small Cap and Mid Cap (d)(e)138
 
 
 138
 149
 
 
 149
75
 
 
 75
 131
 
 
 131
Non-U.S. (e)(f)262
 55
 
 317
 222
 59
 
 281
234
 
 67
 301
 288
 1
 77
 366
Fixed Income Securities (f)(g)23
 390
 
 413
 15
 360
 
 375
11
 350
 130
 491
 29
 324
 130
 483
Hedge Funds and Similar Investments (g)(h)109
 45
 171
 325
 107
 45
 168
 320
97
 
 203
 300
 116
 
 219
 335
Private Equity and Other (h)(i)
 
 153
 153
 
 
 131
 131

 
 281
 281
 
 
 234
 234
Securities Lending (i)(j)(122) (6) 
 (128) (141) (17) 
 (158)(21) (1) 
 (22) (39) (1) 
 (40)
Securities Lending Collateral (i)(j)122
 6
 
 128
 141
 17
 
 158
21
 1
 
 22
 39
 1
 
 40
DTE Energy Total$803
 $490
 $324
 $1,617
 $765
 $464
 $299
 $1,528
$656
 $352
 $681
 $1,689
 $861
 $327
 $660
 $1,848
                              
DTE Electric asset category:                              
Short-term Investments (b)(c)$5
 $
 $
 $5
 $4
 $
 $
 $4
$10
 $1
 $
 $11
 $9
 $1
 $
 $10
Equity Securities 
  
  
 

  
    
 

      

       

U.S. Large Cap (c)(d)183
 
 
 183
 179
 
 
 179
154
 
 
 154
 195
 
 
 195
U.S. Small Cap and Mid Cap (d)(e)97
 
 
 97
 102
 
 
 102
52
 
 
 52
 91
 
 
 91
Non-U.S. (e)(f)184
 37
 
 221
 151
 39
 
 190
163
 
 45
 208
 200
 1
 52
 253
Fixed Income Securities (f)(g)17
 272
 
 289
 11
 243
 
 254
7
 232
 92
 331
 20
 218
 92
 330
Hedge Funds and Similar Investments (g)(h)76
 32
 119
 227
 73
 31
 114
 218
68
 
 139
 207
 80
 
 150
 230
Private Equity and Other (h)(i)
 
 109
 109
 
 
 91
 91

 
 195
 195
 
 
 163
 163
Securities Lending (i)(j)(87) (4) 
 (91) (98) (11) 
 (109)(15) 
 
 (15) (27) (1) 
 (28)
Securities Lending Collateral (i)(j)87
 4
 
 91
 98
 11
 
 109
15
 
 
 15
 27
 1
 
 28
DTE Electric Total$562
 $341
 $228
 $1,131
 $520
 $313
 $205
 $1,038
$454
 $233
 $471
 $1,158
 $595
 $220
 $457
 $1,272

(a)For a description of levels within the fair value hierarchy see Note 1112 to the Consolidated Financial Statements, "Fair Value".Value."
(b)Amounts represent assets valued at NAV as a practical expedient for fair value.
(c)This category predominantly represents certain short-term fixed income securities and money market investments that are managed in separate accounts or commingled funds. Pricing for investments in this category are obtained from quoted prices in actively traded markets or valuations from brokers or pricing services.
(c)(d)This category comprises both actively and not actively managedrepresents portfolios that track the S&P 500 low cost equity index funds.of large capitalization domestic equities. Investments in this category are exchange-traded securities whereby unadjusted quotequoted prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
(d)(e)This category represents portfolios of small and medium capitalization domestic equities. Investments in this category are exchange-traded securities whereby unadjusted quotequoted prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2 assets.
(e)(f)This category primarily consists of portfolios of non-U.S. developed and emerging market equities. Investments in this category are exchange-traded securities whereby unadjusted quotequoted prices can be obtained. Exchange-traded securities held in a commingled fund are classified as Level 2NAV assets.
(f)(g)This category includes corporate bonds from diversified industries, U.S. Treasuries, other governmental debt, bank loans, and mortgage backed securities. Pricing for investments in this category is obtained from quoted prices in actively traded markets and quotations from broker or pricing services. Non-exchange traded securities and exchange-traded securities held in commingled funds are classified as Level 2NAV assets.
(g)(h)This category utilizes a diversified group of strategies that attempt to capture financial market inefficiencies and includes publicly traded debt and equity, publicly traded mutual funds, commingled funds and limited partnership funds, and non-exchange traded securities.funds. Pricing for Level 1 and Level 2 assetsmutual funds in this category is obtained from quoted prices in actively traded marketsmarkets. Commingled funds and quoted prices from broker or pricing services. Non-exchange traded securities held in commingledlimited partnership funds are classified as Level 2NAV assets. Valuations for some Level 3 assets in this category may be based on limited observable inputs as there may be little, if any, publicly available pricing.
(h)(i)This category includes a diversified group of funds and strategies that primarily invests in private equity partnerships. This category also includes investments in timberreal estate and private mezzanine debt. Pricing forAll investments in this category is based on limited observable inputsare classified as there is little, if any, publicly available pricing. Valuations for assets in this category may be based on discounted cash flow analyses, relevant publicly-traded comparables, and comparable transactions.NAV assets.
(i)(j)In 2014, theThe Registrants beganhave a securities lending program with a third-party agent. The program allows the agent to lend certain securities from the Registrants' VEBA trust to selected entities against receipt of collateral (in the form of cash) as provided for and determined in accordance with their securities lending agency agreements.

123


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The DTE Energy Company Master VEBA Trust holds debt and equity securities directly and indirectly through commingled funds and institutional mutual funds. Exchange-traded debt and equity securities held directly are valued using quoted market prices in actively traded markets. The commingled funds and institutional mutual funds hold exchange-traded equity or debt securities and are valued based on NAVs. Non-exchange traded fixed income securities are valued by the trustee based upon quotations available from brokers or pricing services. A primary price source is identified by asset type, class, or issue for each security. The trustee monitors prices supplied by pricing services and may use a supplemental price source or change the primary price source of a given security if the trustee challenges an assigned price and determines that another price source is considered to be preferable. The Registrants have obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Additionally, the Registrants selectively corroborate the fair values of securities by comparison of market-based price sources.
The following table provides a reconciliation of beginning and ending balances of DTE Energy's other postretirement benefit plan assets measured at fair value on a recurring basis where the determination of fair value includes significant unobservable inputs (Level 3):
 Year Ended December 31, 2015 Year Ended December 31, 2014
 Hedge Funds
and Similar
Investments
 Private
Equity and
Other
 Total Hedge Funds
and Similar
Investments
 Private
Equity and
Other
 Total
 (In millions)
Beginning Balance at January 1$168
 $131
 $299
 $159
 $101
 $260
Total realized/unrealized gains (losses)4
 9
 13
 8
 9
 17
Purchases, sales, and settlements:           
Purchases11
 34
 45
 9
 33
 42
Sales(12) (21) (33) (8) (12) (20)
Ending Balance at December 31$171
 $153
 $324
 $168
 $131
 $299
The amount of total gains for the period attributable to the change in unrealized gains or losses related to assets still held at the end of the period$
 $3
 $3
 $7
 $8
 $15
The following table provides a reconciliation of beginning and ending balances of DTE Electric's other postretirement benefit plan assets measured at fair value on a recurring basis where the determination of fair value includes significant unobservable inputs (Level 3):
 Year Ended December 31, 2015 Year Ended December 31, 2014
 Hedge Funds
and Similar
Investments
 Private
Equity and
Other
 Total Hedge Funds
and Similar
Investments
 Private
Equity and
Other
 Total
 (In millions)
Beginning Balance at January 1$114
 $91
 $205
 $111
 $71
 $182
Total realized/unrealized gains (losses)3
 6
 9
 5
 6
 11
Purchases, sales, and settlements:           
Purchases11
 26
 37
 4
 22
 26
Sales(9) (14) (23) (6) (8) (14)
Ending Balance at December 31$119
 $109
 $228
 $114
 $91
 $205
The amount of total gains for the period attributable to the change in unrealized gains or losses related to assets still held at the end of the period$
 $2
 $2
 $5
 $5
 $10
There were no transfers from or into Level 3 and there were no significant transfers between Level 2 and Level 1 in the years ended December 31, 20152018 and 20142017 for either of the Registrants.

124


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Interim Re-Measurement of Other Postretirement Benefit Obligation
In March 2013, the Registrants reached agreements on new four-year labor contracts with certain represented employees under several bargaining units. As a term of the agreements, the Registrants replaced the defined benefit employer-sponsored retiree medical, prescription drug, and dental coverage for future Medicare eligible retirees and their covered dependents with an allocation to a Retiree Reimbursement Account, when the youngest of the retiree's covered household turns age 65. The initial amount of the allocation of $3,250 per year for each eligible participant increases each year at the lower of the rate of medical inflation or 2%. The modification in retiree health coverage will reduce future other postretirement benefit costs.
Based on the impact of such benefit cost savings on the Registrants' Consolidated Financial Statements, the Registrants re-measured their retiree health plan as of March 31, 2013. In performing the re-measurement, the Registrants updated their significant actuarial assumptions, including an adjustment to the discount rate from 4.15% at December 31, 2012 to 4.30% at March 31, 2013. Plan assets were also updated to reflect fair value as of the re-measurement date. Beginning April 2013, net other postretirement benefit costs were recorded based on the updated actuarial assumptions and benefit changes resulting from the new labor contracts.
DTE Energy Common Stock
DTE Energy contributed the following amounts of DTE Energy common stock to the DTE Energy Company Master VEBA Trust for funding its other postretirement benefit plans:
Date Number of Shares Price per Share Amount
      (In millions)
February 17, 2015 1,427,835 $81.91 $117
      $117
The above contribution was made on behalf of DTE Electric, which paid DTE Energy cash consideration of $117 million in February 2015.
During 2015, DTE Energy also made cash contributions of $82 million, including DTE Electric contributions of $58 million, to the DTE Energy Company Master VEBA Trust for its other postretirement benefit plans.
Grantor Trust
DTE Gas maintains a Grantor Trust that invests in life insurance contracts and income securities to fund other postretirement benefit obligations. Employees and retirees have no right, title, or interest in the assets of the Grantor Trust, and DTE Gas can revoke the trust subject to providing the MPSC with prior notification. DTE Gas accounts for its investment at fair value, which approximated $18 million at December 31, 2015 and 2014, with unrealized gains and losses recorded to earnings. The Grantor Trust investment is included in Other investments on DTE Energy's Consolidated Statements of Financial Position.
Defined Contribution Plans
The Registrants also sponsor defined contribution retirement savings plans. Participation in one of these plans is available to substantially all represented and non-represented employees. For substantially all employees, the Registrants match employee contributions up to certain predefined limits based upon eligible compensation and the employee’s contribution rate. TheAdditionally, for eligible represented and non-represented employees who do not participate in the Pension Plans, the Registrants annually contribute an amount equivalent to 4% (8% for certain DTE Gas represented employees) of an employee's eligible pay to the employee's defined contribution retirement savings plan. For DTE Energy, the cost of these plans was $49$61 million, $48$57 million, and $41$51 million in each offor the years 2015, 2014,ended December 31, 2018, 2017, and 2013, respectively, for2016, respectively. For DTE Energy,Electric, the cost of these plans was $29 million, $27 million, and $23 million $24 million, and $21 million in each offor the years 2015, 2014,ended December 31, 2018, 2017, and 2013, respectively, for DTE Electric.
Plan Changes
In 2015, certain executive retirement benefit plans were amended to transfer the obligation for benefits as attributed to the LLC. The related plan liabilities were transferred from DTE Electric and DTE Gas to the LLC. The related Rabbi Trust assets were also transferred to DTE Energy from DTE Electric.2016.


125


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

NOTE 1921 — STOCK-BASED COMPENSATION
DTE Energy’s stock incentive program permits the grant of incentive stock options, non-qualifying stock options, stock awards, performance shares, and performance units to employees and members of its Board of Directors. As a result of a stock award, a settlement of an award of performance shares, or by exercise of a participant’s stock option, DTE Energy may deliver common stock from its authorized but unissued common stock and/or from outstanding common stock acquired by or on behalf of DTE Energy in the name of the participant. Key provisions of the stock incentive program are:
Authorized limit is 14,500,00016,500,000 shares of common stock;
Prohibits the grant of a stock option with an exercise price that is less than the fair market value of DTE Energy’s stock on the date of the grant; and
Imposes the following award limits to a single participant in a single calendar year, (1) options for more than 500,000 shares of common stock; (2) stock awards for more than 150,000 shares of common stock; (3) performance share awards for more than 300,000 shares of common stock (based on the maximum payout under the award); or (4) more than 1,000,000 performance units, which have a face amount of $1.00 each.
DTE Energy records compensation expense at fair value over the vesting period for all awards it grants.
The following table summarizes the components of stock-based compensation for DTE Energy:
2015 2014 20132018 2017 2016
(In millions)(In millions)
Stock-based compensation expense$34
 $103
 $99
$64
 $58
 $61
Tax benefit$13
 $40
 $38
$13
 $23
 $24
Stock-based compensation cost capitalized in Property, plant, and equipment$5
 $16
 $15
$11
 $9
 $10

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Stock Options
Options are exercisable according to the terms of the individual stock option award agreements and expire ten years after the date of the grant. The option exercise price equals the fair value of the stock on the date that the option was granted. Stock options vest ratably over a three-year period.
The following table summarizes DTE Energy's stock option activity for the year ended December 31, 2015:2018:
 Number of Options Weighted Average Exercise Price Aggregate Intrinsic
Value
(In millions)
Options outstanding at December 31, 2014444,278
 $43.56
  
Exercised(178,017) $45.07
  
Forfeited or expired(3,979) $44.72
  
Options outstanding and exercisable at December 31, 2015262,282
 $42.52
 $10
 Number of Options Weighted Average Exercise Price Aggregate Intrinsic
Value
(In millions)
Options outstanding and exercisable at December 31, 2017105,994
 $42.95
  
Exercised(53,894) $42.62
  
Options outstanding and exercisable at December 31, 201852,100
 $43.30
 $4
As of December 31, 2015,2018, the weighted average remaining contractual life for the exercisable shares is 2.801.11 years. As of December 31, 2015,2018, all options were vested. No options vested during 2015.2018.
There were no options granted during 2015, 2014,2018, 2017, or 2013.2016. The intrinsic value of options exercised for the years ended December 31, 2015, 2014,2018 was $4 million. The intrinsic value of options for the years ended December 31, 2017 and 20132016 was $7 million, $11 million, and $12 million, respectively.$4 million. No option expense was recognized for 2015, 2014,2018, 2017, or 2013.2016.

126


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The number, weighted average exercise price, and weighted average remaining contractual life of DTE Energy options outstanding as of December 31, 20152018 were as follows:
Range of Exercise PricesRange of Exercise Prices Number of Options Weighted Average
Exercise Price
 Weighted Average
Remaining Contractual Life (Years)
Range of Exercise Prices Number of Options Weighted Average
Exercise Price
 Weighted Average
Remaining Contractual Life (Years)
$27.00 — $38.00
 22,083
 $27.70
 3.1627.00 — $38.00
 2,100
 $27.70
 0.16
$38.01 — $42.00
 80,434
 $41.79
 2.1642.01 — $45.00
 50,000
 $43.95
 1.15
$42.01 — $45.00
 116,665
 $43.90
 3.79
$45.01 — $50.00
 43,100
 $47.75
 1.15
   262,282
 $42.52
 2.80    52,100
 $43.30
 1.11
Restricted Stock Awards
Stock awards granted under the plan are restricted for varying periods, generally for three years. Participants have all rights of a shareholder with respect to a stock award, including the right to receive dividends and vote the shares. Prior to vesting in stock awards, the participant: (i) may not sell, transfer, pledge, exchange, or otherwise dispose of shares; (ii) shall not retain custody of the share certificates; and (iii) will deliver to DTE Energy a stock power with respect to each stock award upon request.
The stock awards are recorded at cost that approximates fair value on the date of grant. The cost is amortized to compensation expense over the vesting period.
Stock award activity for DTE Energy for the years ended December 31 was:
2015 2014 20132018 2017 2016
Fair value of awards vested (in millions)$9
 $11
 $8
$11
 $10
 $9
Restricted common shares awarded144,300
 159,590
 127,785
109,393
 136,825
 145,240
Weighted average market price of shares awarded$83.43
 $70.09
 $64.72
$105.80
 $99.53
 $87.28
Compensation cost charged against income (in millions)$10
 $10
 $23
$11
 $11
 $11

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following table summarizes DTE Energy’s restricted stock awards activity for the year ended December 31, 2015:2018:
Restricted
Stock
 Weighted Average
Grant Date
Fair Value
Restricted
Stock
 Weighted Average
Grant Date
Fair Value
Balance at December 31, 2014416,318
 $62.82
Balance at December 31, 2017365,764
 $90.26
Grants144,300
 $83.43
109,393
 $105.80
Forfeitures(12,721) $74.78
(21,939) $98.59
Vested and issued(165,453) $55.73
(125,813) $85.24
Balance at December 31, 2015382,444
 $73.26
Balance at December 31, 2018327,405
 $96.79
Performance Share Awards
Performance shares awarded under the plan are for a specified number of shares of DTE Energy common stock that entitle the holder to receive a cash payment, shares of DTE Energy common stock, or a combination thereof. The final value of the award is determined by the achievement of certain performance objectives and market conditions. The awards vest at the end of a specified period, usually three years. Awards granted in 20142018, 2017, and 20152016 were primarily deemed to be equity awards. The DTE Energy stock price and number of probable shares attributable to market conditions for such equity awards are fair valued only at the grant date. Performance shares awarded prior to 2014 are liability awards and are remeasured to fair value at each reporting period. DTE Energy accounts for performance share awards by accruing compensation expense over the vesting period based on: (i) the number of shares expected to be paid which is based on the probable achievement of performance objectives; and (ii) the closing stock price market value. The settlement of the award is based on the closing price at the settlement date.

127


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

DTE Energy recorded compensation expense for performance share awards as follows:
 2015 2014 2013
 (In millions)
Compensation expense$24
 $93
 $77
Cash settlements (a)$13
 $11
 $9
Stock settlements (a)$71
 $61
 $56
 2018 2017 2016
 (In millions)
Compensation expense$53
 $47
 $50
Cash settlements(a)
$13
 $15
 $7
Stock settlements(a)
$39
 $66
 $38

(a)Sum of cash and stock settlements approximates the intrinsic value of the awards.
During the vesting period, the recipient of a performance share award has no shareholder rights. During the period beginning on the date the performance shares are awarded and ending on the certification date of the performance objectives, the number of performance shares awarded will be increased, assuming full dividend reinvestment at the fair market value on the dividend payment date. The cumulative number of performance shares will be adjusted to determine the final payment based on the performance objectives achieved. Performance share awards are nontransferable and are subject to risk of forfeiture.
The following table summarizes DTE Energy’s performance share activity for the period ended December 31, 2015:2018:
Performance Shares Weighted Average
Grant Date
Fair Value
Performance Shares Weighted Average
Grant Date
Fair Value
Balance at December 31, 20141,554,697
 $69.32
Balance at December 31, 20171,324,401
 $90.31
Grants467,288
 $83.85
437,508
 $105.64
Forfeitures(47,067) $76.22
(56,435) $96.02
Payouts(532,700) $
(418,788) $84.84
Balance at December 31, 20151,442,218
 $75.85
Balance at December 31, 20181,286,686
 $97.17

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Unrecognized Compensation Costs
As of December 31, 2015,2018, DTE Energy's total unrecognized compensation cost related to non-vested stock incentive plan arrangements and the weighted average recognition period was as follows:
Unrecognized
Compensation
Cost
 Weighted Average
to be Recognized
Unrecognized
Compensation
Cost
 Weighted Average
to be Recognized
(In millions) (In years)(In millions) (In years)
Stock awards$11
 1.11$12
 1.03
Performance shares37
 0.9759
 1.04
$48
 1.00$71
 1.04
Allocated Stock-Based Compensation
DTE Electric received an allocation of costs from DTE Energy associated with stock-based compensation. DTE Electric's allocation for 2015, 2014,2018, 2017, and 20132016 for stock-based compensation expense was approximately $21$38 million, $62$34 million, and $58$38 million, respectively.

NOTE 2022 — SEGMENT AND RELATED INFORMATION
DTE Energy sets strategic goals, allocates resources, and evaluates performance based on the following structure:
Electric segment consists principally of DTE Electric, which is engaged in the generation, purchase, distribution, and sale of electricity to approximately 2.2 million residential, commercial, and industrial customers in southeastern Michigan.

128


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Gas segment consists principally of DTE Gas, which is engaged in the purchase, storage, transportation, distribution, and sale of natural gas to approximately 1.21.3 million residential, commercial, and industrial customers throughout Michigan and the sale of storage and transportation capacity.
Gas Storage and Pipelines consistsis primarily engaged in services related to the gathering, transportation, and storage of natural gas pipeline, gathering, and storage businesses.gas.
Power and Industrial Projects is comprised primarily of projects that deliver energy and utility-type products and services to industrial, commercial, and institutional customers, produce reduced emissions fuel, and sell electricity and pipeline-quality gas from renewable energy projects.
Energy Trading consists of energy marketing and trading operations.
Corporate and Other includes various holding company activities, holds certain non-utility debt, and holds energy-related investments.
The federal income tax provisions or benefits of DTE Energy’s subsidiaries are determined on an individual company basis and recognize the tax benefit of tax credits and net operating losses, if applicable. The state and local income tax provisions of the utility subsidiaries are determined on an individual company basis and recognize the tax benefit of various tax credits and net operating losses, if applicable. The subsidiaries record federal, state, and local income taxes payable to or receivable from DTE Energy based on the federal, state, and local tax provisions of each company.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Inter-segment billing for goods and services exchanged between segments is based upon tariffed or market-based prices of the provider and primarily consists of the sale of reduced emissions fuel, power sales, and natural gas sales in the following segments:
Year Ended December 31,Year Ended December 31,
2015 2014 20132018 2017 2016
(In millions)(In millions)
Electric$36
 $29
 $26
$52
 $48
 $43
Gas3
 6
 4
12
 8
 9
Gas Storage and Pipelines8
 9
 3
36
 42
 9
Power and Industrial Projects785
 794
 816
642
 569
 602
Energy Trading32
 33
 43
27
 35
 39
Corporate and Other4
 3
 (24)2
 2
 2
$868
 $874
 $868
$771
 $704
 $704

Financial data of DTE Energy's business segments follows:
129

 Electric Gas Gas Storage and Pipelines Power and Industrial Projects Energy Trading Corporate and Other Reclassifications
and
Eliminations
 Total
 (In millions)
2018               
Operating Revenues — Utility operations$5,298
 1,436
 
 
 
 
 (64) $6,670
Operating Revenues — Non-utility operations$
 
 485
 2,204
 5,557
 3
 (707) $7,542
Depreciation and amortization$836
 133
 82
 67
 5
 1
 
 $1,124
Interest expense$283
 70
 68
 31
 6
 220
 (119) $559
Interest income$
 (6) (9) (9) (3) (104) 119
 $(12)
Equity in earnings of equity method investees$
 2
 123
 3
 
 4
 
 $132
Income Tax Expense (Benefit)$193
 67
 68
 (195) 13
 (48) 
 $98
Net Income (Loss) Attributable to DTE Energy Company$664
 150
 235
 161
 39
 (129) 
 $1,120
Investment in equity method investees$7
 12
 1,585
 134
 
 33
 
 $1,771
Capital expenditures and acquisitions$1,979
 460
 176
 91
 5
 2
 
 $2,713
Goodwill$1,208
 743
 299
 26
 17
 
 
 $2,293
Total Assets$22,501
 5,378
 3,161
 495
 909
 6,153
 (2,309) $36,288


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

Financial data of DTE Energy's business segments follows:
Electric Gas Gas Storage and Pipelines Power and Industrial Projects Energy Trading Corporate and Other Reclassifications
and
Eliminations
 TotalElectric Gas Gas Storage and Pipelines Power and Industrial Projects Energy Trading Corporate and Other Reclassifications
and
Eliminations
 Total
(In millions)(In millions)
2015               
2017               
Operating Revenues — Utility operations$4,901
 1,376
 
 
 
 
 (39) $6,238
$5,102
 1,388
 
 
 
 
 (56) $6,434
Operating Revenues — Non-utility operations$
 
 243
 2,224
 2,459
 2
 (829) $4,099
$
 
 453
 2,089
 4,277
 2
 (648) $6,173
Depreciation and amortization$637
 104
 30
 78
 2
 1
 
 $852
$753
 123
 76
 72
 5
 1
 
 $1,030
Interest expense$274
 65
 77
 29
 5
 192
 (106) $536
Interest income$
 (7) (8) (8) (2) (52) 64
 $(13)$
 (7) (14) (7) (2) (88) 106
 $(12)
Interest expense$258
 62
 24
 32
 6
 132
 (64) $450
Equity in earnings of equity method investees$2
 6
 47
 8
 
 3
 
 $66
$1
 2
 90
 9
 
 
 
 $102
Income Tax Expense (Benefit)$290
 72
 70
 (140) (15) (47) 
 $230
$321
 78
 (30) (195) 49
 (48) 
 $175
Net Income (Loss) Attributable to DTE Energy Company$542
 132
 107
 16
 (22) (48) 
 $727
$606
 146
 275
 138
 72
 (103) 
 $1,134
Investment in equity method investees$10
 9
 296
 183
 
 16
 
 $514
$7
 11
 879
 150
 
 26
 
 $1,073
Capital expenditures and acquisitions$1,785
 273
 161
 36
 6
 
 
 $2,261
$1,574
 463
 137
 56
 7
 13
 
 $2,250
Goodwill$1,208
 743
 24
 26
 17
 
 
 $2,018
$1,208
 743
 299
 26
 17
 
 
 $2,293
Total Assets$19,539
 4,299
 1,047
 860
 590
 3,530
 (1,128) $28,737
$21,163
 5,072
 2,594
 593
 725
 5,324
 (1,704) $33,767

(a)Includes Income Tax Expense (Benefit) of $(5) million, $(115) million, $(21) million, $2 million, and $34 million for Electric — non-utility, Gas Storage and Pipelines, Power and Industrial Projects, Energy Trading, and Corporate and Other, respectively, related to the enactment of the TCJA.
Electric Gas Gas Storage and Pipelines Power and Industrial Projects Energy Trading Corporate and Other Reclassifications
and
Eliminations
 TotalElectric Gas Gas Storage and Pipelines Power and Industrial Projects Energy Trading Corporate and Other Reclassifications
and
Eliminations
 Total
(In millions)(In millions)
2014               
2016               
Operating Revenues — Utility operations$5,283
 1,636
 
 
 
 
 (35) $6,884
$5,225
 1,324
 
 
 
 
 (52) $6,497
Operating Revenues — Non-utility operations$
 
 203
 2,289
 3,762
 2
 (839) $5,417
$
 
 302
 1,906
 2,575
 2
 (652) $4,133
Depreciation and amortization$933
 99
 34
 77
 1
 1
 
 $1,145
$750
 106
 45
 72
 3
 
 
 $976
Interest expense$264
 60
 39
 32
 6
 148
 (77) $472
Interest income$(1) (7) (6) (5) 
 (48) 57
 $(10)$(8) (6) (9) (8) (1) (65) 77
 $(20)
Interest expense$250
 57
 22
 28
 7
 122
 (57) $429
Equity in earnings of equity method investees$1
 7
 35
 5
 
 
 
 $48
$2
 6
 60
 
 
 
 
 $68
Income Tax Expense (Benefit)$296
 78
 53
 (100) 77
 (40) 
 $364
$353
 77
 71
 (140) (29) (61) 
 $271
Net Income (Loss) Attributable to DTE Energy Company$528
 140
 82
 90
 122
 (57) 
 $905
$622
 138
 119
 95
 (45) (61) 
 $868
Investment in equity method investees$8
 10
 224
 184
 
 8
 
 $434
$11
 10
 538
 166
 
 27
 
 $752
Capital expenditures and acquisitions$1,561
 224
 184
 77
 3
 
 
 $2,049
$1,503
 395
 1,322
 39
 7
 3
 
 $3,269
Goodwill$1,208
 743
 24
 26
 17
 
 
 $2,018
$1,208
 743
 292
 26
 17
 
 
 $2,286
Total Assets$18,713
 4,247
 883
 998
 755
 3,209
 (906) $27,899
$20,417
 4,729
 2,417
 683
 660
 4,648
 (1,513) $32,041

130


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

 Electric Gas Gas Storage and Pipelines Power and Industrial Projects Energy Trading Corporate and Other Reclassifications
and
Eliminations
 Total
 (In millions)
2013               
Operating Revenues — Utility operations$5,199
 1,474
 
 
 
 
 (30) $6,643
Operating Revenues — Non-utility operations$
 
 132
 1,950
 1,771
 3
 (838) $3,018
Depreciation and amortization$902
 95
 23
 72
 1
 1
 
 $1,094
Interest income$(1) (7) (7) (6) 
 (51) 63
 $(9)
Interest expense$268
 58
 18
 27
 8
 120
 (63) $436
Equity in earnings of equity method investees$1
 6
 44
 8
 
 
 
 $59
Income Tax Expense (Benefit)$252
 77
 45
 (45) (38) (37) 
 $254
Net Income (Loss) Attributable to DTE Energy Company$484
 143
 70
 66
 (58) (44) 
 $661
Investment in equity method investees$9
 10
 201
 189
 
 6
 
 $415
Capital expenditures and acquisitions$1,325
 209
 245
 93
 3
 1
 
 $1,876
Goodwill$1,208
 743
 24
 26
 17
 
 
 $2,018
Total Assets$17,508
 3,920
 823
 1,054
 624
 2,945
 (939) $25,935

NOTE 2123 — RELATED PARTY TRANSACTIONS
DTE Electric has agreements with affiliated companies to sell energy for resale, purchase fuel and power, provide fuel supply services, and provide power plant operation and maintenance services. DTE Electric has agreements with certain DTE Energy affiliates where DTE Electric charges the affiliates for their use of the shared capital assets of DTE Electric. A shared services company accumulates various corporate support services expenses and charges various subsidiaries of DTE Energy, including DTE Electric. DTE Electric records federal, state, and local income taxes payable to or receivable from DTE Energy based on its federal, state, and local tax provisions.

DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

The following is a summary of DTE Electric's transactions with affiliated companies:
2015 2014 20132018 2017 2016
(In millions)(In millions)
Revenues          
Energy sales$2
 $2
 $2
$9
 $9
 $10
Other services$6
 $5
 $7
$(4) $(4) $(1)
Shared capital assets$33
 $26
 $23
$43
 $39
 $33
Costs          
Fuel and purchased power$9
 $4
 $4
$7
 $6
 $10
Other services and interest$2
 $(1) $(1)$33
 $(2) $(1)
Corporate expenses (net)$334
 $304
 $334
Corporate expenses, net$377
 $370
 $370
Other          
Dividends declared$395
 $370
 $342
$461
 $432
 $420
Dividends paid$395
 $370
 $342
$461
 $432
 $420
Capital contribution from DTE Energy$300
 $190
 $400
$325
 $100
 $120
DTE Electric's Accounts receivable and Accounts payable related to Affiliates are payable upon demand and are generally settled in cash within a monthly business cycle. Notes receivable and Short-term borrowings related to Affiliates are subject to a credit agreement with DTE Energy whereby short-term excess cash or cash shortfalls are remitted to or funded by DTE Energy. This credit arrangement involves the charge and payment of interest at market-based rates. Refer to DTE Electric's Consolidated Statements of Financial Position for affiliate balances at December 31, 20152018 and 2014.

131


2017.
DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

For DTE Electric, thereThere were no charitable contributions by DTE Electric to the DTE Energy Foundation for the years ended December 31, 20152018 and 2014, while there were $182016. DTE Electric's charitable contributions to the DTE Energy Foundation was $7 million in contributions for the year ended December 31, 2013.2017. The DTE Energy Foundation is a non-consolidated not-for-profit private foundation, the purpose of which is to contribute and assist charitable organizations.
See the following notes for other related party transactions impacting DTE Electric’s Consolidated Financial Statements:
Note Title
41 AcquisitionsOrganization and Exit ActivitiesBasis of Presentation
1820 Retirement Benefits and Trusteed Assets
1921 Stock-Based Compensation


DTE Energy Company — DTE Electric Company
Combined Notes to Consolidated Financial Statements — (Continued)

NOTE 2224 — SUPPLEMENTARY QUARTERLY FINANCIAL INFORMATION (UNAUDITED)
DTE Energy
Quarterly earnings per share may not equal full year totals, since quarterly computations are based on weighted average common shares outstanding during each quarter.
First
Quarter
 Second
Quarter
 Third
Quarter
 Fourth
Quarter
 YearFirst
Quarter
 Second
Quarter
 Third
Quarter
 Fourth
Quarter
 Year
(In millions, except per share amounts)(In millions, except per share amounts)
2015         
2018         
Operating Revenues$2,984
 $2,268
 $2,598
 $2,487
 $10,337
$3,753
 $3,159
 $3,550
 $3,750
 $14,212
Operating Income$461
 $204
 $440
 $134
 $1,239
$504
 $329
 $429
 $332
 $1,594
Net Income Attributable to DTE Energy Company$273
 $109
 $265
 $80
 $727
$361
 $234
 $334
 $191
 $1,120
Basic Earnings per Share$1.53
 $0.61
 $1.47
 $0.45
 $4.05
$2.01
 $1.29
 $1.84
 $1.05
 $6.18
Diluted Earnings per Share$1.53
 $0.61
 $1.47
 $0.45
 $4.05
$2.00
 $1.29
 $1.84
 $1.05
 $6.17
2014         
2017         
Operating Revenues$3,930
 $2,698
 $2,595
 $3,078
 $12,301
$3,236
 $2,855
 $3,245
 $3,271
 $12,607
Operating Income$560
 $249
 $239
 $542
 $1,590
Net Income Attributable to DTE Energy Company$326
 $124
 $156
 $299
 $905
Operating Income(a)
$585
 $320
 $434
 $372
 $1,711
Net Income Attributable to DTE Energy Company(b)
$400
 $177
 $270
 $287
 $1,134
Basic Earnings per Share$1.84
 $0.70
 $0.88
 $1.68
 $5.11
$2.23
 $0.99
 $1.51
 $1.60
 $6.32
Diluted Earnings per Share$1.84
 $0.70
 $0.88
 $1.68
 $5.10
$2.23
 $0.99
 $1.51
 $1.60
 $6.32

(a)
Pursuant to the implementation of ASU 2017-07, amounts previously included in Operating Income Operation and maintenance were reclassified to Other (Income) and Deductions Non-operating retirement benefits, net on DTE Energy's Consolidated Statements of Operations.
(b)Includes a net Income Tax Benefit of $(105) million related to the enactment of the TCJA in the fourth quarter.
DTE Electric
First
Quarter
 Second
Quarter
 Third
Quarter
 Fourth
Quarter
 YearFirst
Quarter
 Second
Quarter
 Third
Quarter
 Fourth
Quarter
 Year
(In millions)(In millions)
2015         
2018         
Operating Revenues$1,203
 $1,147
 $1,385
 $1,165
 $4,900
$1,205
 $1,276
 $1,521
 $1,296
 $5,298
Operating Income$268
 $214
 $400
 $192
 $1,074
$253
 $269
 $444
 $168
 $1,134
Net Income$137
 $99
 $216
 $92
 $544
$140
 $163
 $305
 $56
 $664
2014         
2017         
Operating Revenues$1,410
 $1,281
 $1,357
 $1,234
 $5,282
$1,175
 $1,218
 $1,434
 $1,275
 $5,102
Operating Income$271
 $259
 $272
 $250
 $1,052
$217
 $272
 $395
 $281
 $1,165
Net Income$137
 $130
 $136
 $129
 $532
$106
 $138
 $219
 $138
 $601


132




Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure
None.

Item 9A. Controls and Procedures
See Item 8. Financial Statements and Supplementary Data for management’s evaluation of the Registrants' disclosure controls and procedures, their report on internal control over financial reporting, and their conclusion on changes in internal control over financial reporting.

Item 9B. Other Information
None.

Part III
Item 10. Directors, Executive Officers, and Corporate Governance

Item 11. Executive Compensation

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

Item 13. Certain Relationships and Related Transactions, and Director Independence
DTE Electric
Information required of DTE Electric by Part III (Items 10, 11, 12, and 13) of this Form 10-K is omitted per General Instruction I (2) (c) of Form 10-K for wholly-owned subsidiaries (reduced disclosure format).

Item 14. Principal Accountant Fees and Services
DTE Energy
Information required of DTE Energy by Part III (Items 10, 11, 12, 13, and 14) of this Form 10-K is incorporated by reference from DTE Energy’s definitive Proxy Statement for its 20162019 Annual Meeting of Shareholders to be held May 5, 2016.9, 2019. The Proxy Statement will be filed with the SEC, pursuant to Regulation 14A, not later than 120 days after the end of DTE Energy's fiscal year covered by this report on Form 10-K, all of which information is hereby incorporated by reference in, and made part of, this Form 10-K.

133




DTE Electric
For the years ended December 31, 20152018 and 2014,2017, professional services were performed by PricewaterhouseCoopers LLP (PwC). The following table presents fees for professional services rendered by PwC for the audit of DTE Electric’s annual financial statements for the years ended December 31, 20152018 and December 31, 2014,2017, respectively, and fees billed for other services rendered by PwC during those periods.
 2015 2014
Audit fees (a)$1,329,245
 $1,337,674
Audit-related fees (b)12,000
 11,000
Total$1,341,245
 $1,348,674
 2018 2017
Audit fees(a)
$1,393,500
 $1,428,500
Audit-related fees(b)
52,000
 12,000
Total$1,445,500
 $1,440,500

(a)Represents the aggregate fees for the audits of DTE Electric’s annual financial statements included in the Annual Reports on Form 10-K and for the reviews of the financial statements included in the Quarterly Reports on Form 10-Q.
(b)Represents the aggregate fees billed for audit-related services for various attest services.
The above listed fees were pre-approved by the DTE Energy Audit Committee. Prior to engagement, the DTE Energy Audit Committee pre-approves these services by category of service. The DTE Energy Audit Committee may delegate to the chair of the Audit Committee, or to one or more other designated members of the Audit Committee, the authority to grant pre-approvals of all permitted services or classes of these permitted services to be provided by the independent auditor up to, but not exceeding, a pre-defined limit. The decision of the designated member to pre-approve a permitted service will be reported to the DTE Energy Audit Committee at the next scheduled meeting.

134




Part IV
Item 15. Exhibits and Financial Statement Schedules
A.The following documents are filed as part of this Annual Report on Form 10-K.
(1)Consolidated Financial Statements. See “Item"Item 8 — Financial Statements and Supplementary Data."
(2)Financial statement schedule. See “Item"Item 8 — Financial Statements and Supplementary Data."
(3)Exhibits.
Exhibit Number Description 
DTE
Energy
 
DTE
Electric
       
  (i) Exhibits filed herewith:    
       
10.96Third Amendment to the DTE Energy Company Executive Supplemental Retirement Plan (Amended and Restated Effective January 1, 2005) dated as of February 3, 2016X
10.97First Amendment to DTE Energy Company Executive Performance Plan Effective May 7, 2015, dated as of February 3, 2016X
10.98First Amendment to DTE Energy Company Executive Deferred Compensation Plan as Amended and Restated, effective as of January 1, 2005, dated as of February 4, 2016X
10.99First Amendment to DTE Energy Company Long-Term Incentive Plan Amended and Restated Effective May 1, 2014, dated as of February 4, 2016X
12.65Computation of Ratio of Earnings to Fixed ChargesX
12.66Computation of Ratio of Earnings to Fixed ChargesX
21.11 Subsidiaries of DTE Energy X  
       
23.30 Consent of PricewaterhouseCoopers LLP X  
       
23.31 Consent of PricewaterhouseCoopers LLP   X
       
31.109 Chief Executive Officer Section 302 Form 10-K Certification of Periodic Report X  
       
31.110 Chief Financial Officer Section 302 Form 10-K Certification of Periodic Report X  
       
31.111 Chief Executive Officer Section 302 Form 10-K Certification of Periodic Report   X
       
31.112 Chief Financial Officer Section 302 Form 10-K Certification of Periodic Report   X
       
101.INS XBRL Instance Document X X
       
101.SCH XBRL Taxonomy Extension Schema X X
       
101.CAL XBRL Taxonomy Extension Calculation Linkbase X X
       
101.DEF XBRL Taxonomy Extension Definition Database X X
       
101.LAB XBRL Taxonomy Extension Label Linkbase X X
       
101.PRE XBRL Taxonomy Extension Presentation Linkbase X X
       
  (ii) Exhibits furnished herewith:    
       
32.109 Chief Executive Officer Section 906 Form 10-K Certification of Periodic Report X  
       
32.110 Chief Financial Officer Section 906 Form 10-K Certification of Periodic Report X  
       
32.111 Chief Executive Officer Section 906 Form 10-K Certification of Periodic Report   X
       
32.112 Chief Financial Officer Section 906 Form 10-K Certification of Periodic Report   X

135



  (iii) Exhibits incorporated by reference:    
       
Certain exhibits listed below refer to "The Detroit Edison Company" and "Michigan Consolidated Gas Company" and were effective prior to the change to DTE Electric Company and DTE Gas Company, respectively, effective January 1, 2013.
       
3(a)  X  
       
3(b)  X  
       
3(c)X
3(d)X


Exhibit NumberDescription
DTE
Energy
DTE
Electric
4(a)  X  
       
   X  
       
  Supplemental Indenture, dated as of May 15, 2006, between DTE Energy Company and The Bank of New York, as trustee (Exhibit 4-239 to DTE Energy’s Form 10-Q for the quarter ended June 30, 2006). (2006 Series B 6.35% Senior Notes due 2016)X
Supplemental Indenture, dated as of December 1, 2011, between DTE Energy Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit 4-274 to DTE Energy’s Form 8-K dated December 7, 2011). (2011 Series I 6.50% Junior Subordinated Debentures due 2061)X
 X  
       
   X  
       
   X  
       
   X  
       
  
X

X

 X  
X

X
X
X
X


Exhibit NumberDescription
DTE
Energy
DTE
Electric
       
4(b) Mortgage and Deed of Trust, dated as of October 1, 1924, between The Detroit Edison Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit B-1 to Detroit Edison's Registration Statement on Form A-2 (File No. 2-1630)) and indentures supplemental thereto, dated as of dates indicated below, and filed as exhibits to the filings set forth below: X X
       
  Supplemental Indenture, dated as of December 1, 1940, to the Mortgage and Deed of Trust, dated as of October 1, 1924, between The Detroit Edison Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit B-14 to Detroit Edison's Registration Statement on Form A-2 (File No. 2-4609)). (amendment) X X
       
  Supplemental Indenture, dated as of September 1, 1947, to the Mortgage and Deed of Trust, dated as of October 1, 1924, between The Detroit Edison Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit B-20 to Detroit Edison's Registration Statement on Form S-1 (File No. 2-7136)). (amendment) X X

136



       
  Supplemental Indenture, dated as of March 1, 1950, to the Mortgage and Deed of Trust, dated as of October 1, 1924, between The Detroit Edison Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit B-22 to Detroit Edison's Registration Statement on Form S-1 (File No. 2-8290)). (amendment) X X
       
  Supplemental Indenture, dated as of November 15, 1951, to the Mortgage and Deed of Trust, dated as of October 1, 1924, between The Detroit Edison Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit B-23 to Detroit Edison's Registration Statement on Form S-1 (File No. 2-9226)). (amendment) X X
       
  Supplemental Indenture, dated as of August 15, 1957, to the Mortgage and Deed of Trust, dated as of October 1, 1924, between The Detroit Edison Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit 3-B-30 to Detroit Edison's Form 8-K dated September 11, 1957). (amendment) X X
       
  Supplemental Indenture, dated as of December 1, 1966, to the Mortgage and Deed of Trust, dated as of October 1, 1924, between The Detroit Edison Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit 2-B-32 to Detroit Edison's Registration Statement on Form S-9 (File No. 2-25664)). (amendment) X X
       
  Supplemental Indenture, dated as of February 15, 1990, to the Mortgage and Deed of Trust, dated as of October 1, 1924, between The Detroit Edison Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit 4-212 to Detroit Edison's Form 10-K for the year ended December 31, 2000). (1990 Series B)XX
 X X
       
   X X
       
   X X
       
   X X
       
   X X
       
   X X
       


Exhibit NumberDescription
DTE
Energy
DTE
Electric
  
 X X
       
   X X
       

137



   X X
       
   X X
       
   X X
       
   X X
       
  Supplemental Indenture, dated as of June 1, 2008 to Mortgage and Deed of Trust, dated as of October 1, 1924 between The Detroit Edison Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit 4-255 to Detroit Edison's Form 10-Q for the quarter ended June 30, 2008). (2008 Series G)XX
 X X
       
   X X
       
   X X
       
   X X
       
   X X
       
   X X
       
   X X
       


Exhibit NumberDescription
DTE
Energy
DTE
Electric
  
 X X
       

138



   X X
       
   X X
       
   X X
       
   X X
       
  XX
XX
XX
 X X
       
4(c) Collateral Trust Indenture, dated as of June 30, 1993, between The Detroit Edison Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit 4-152 to Detroit Edison's Registration Statement (File No. 33-50325)) and indentures supplemental thereto, dated as of dates indicated below, and filed as exhibits to the filings set forth below: X X
       
   X X
       
   X X
       


Exhibit NumberDescription
DTE
Energy
DTE
Electric
  
 X X
       
   X X
       
   X X
       
   X X
       

139



   X X
       
  Twenty-fifth Supplemental Indenture, dated as of June 1, 2008 to the Collateral Trust Indenture, dated as of June 30, 1993 between The Detroit Edison Company and The Bank of New York Mellon Trust Company, N.A., as successor trustee (Exhibit 4-256 to Detroit Edison's Form 10-Q for the quarter ended June 30, 2008). (2008 Series G 5.60% Senior Notes due 2018)XX
 X X
       
   X X
       
   X X
       
4(d)  X  
       
   X  
       
   X  
       


Exhibit NumberDescription
DTE
Energy
DTE
Electric
  
 X  
       
   X  
       
  X
 X  
       
4(e) Indenture of Mortgage and Deed of Trust dated as of March 1, 1944 (Exhibit 7-D to Michigan Consolidated Gas Company Registration Statement No. 2-5252) and indentures supplemental thereto, dated as of dates indicated below, and filed as exhibits to the filings set forth below: X  
       

140



   X  
       
   X  
       
   X  
       
   X  
       
   X  
       
   X  
       
   X  
       


Exhibit NumberDescription
DTE
Energy
DTE
Electric
  
 X  
       
   X  
       
4(f) Registration Rights Agreement,X
 X  
       
10(a)  X  
       
10(b) Certain arrangements pertaining to the employment of Gerard M. Anderson with The Detroit Edison Company, dated October 6, 1993 (Exhibit 10-48 to The Detroit Edison Company's Form 10-K for the year ended December 31, 1993) X X
       
10(c)  X X
       
10(d)  X  
       
10(e)  X  

141



       
10(f) Amended and Restated  X  
       
10(g)  X  
       
10(h)  X X
       
10(i)  X  
       
10(j)  X  
       
   X  
       
10(k)  X  
       
10(l)  X  
       


Exhibit NumberDescription
DTE
Energy
DTE
Electric
10(m)  X  
       
   X  
       
  X
 X  
       
10(n)  X  
       
   X  
       
   X  
       
10(o)  X  
       
   X  
       
10(p) X
 X  
       
10(q)  X  
       

142



   X  
       
10(r)  X  
       
10(s) X


Exhibit NumberDescription
DTE
Energy
DTE
Electric
 X  
       
10(t)  X  
       
X

10(u) XX
 X X
       
10(v)  X  
       
10(w)  X  
       
10(x) Form of Change-In-Control Severance AgreementX
99(a)Amendment and Restatement of Master Trust Agreement for the DTE Energy Company Master Plan Trust between DTE Energy Corporate Services, LLC and DTE Energy Investment Committee and JP Morgan Chase Bank, N.A., dated as of October 15, 2010 (Exhibit 99-54 to DTE Energy’sEnergy's Form 10-K for the year ended December 31, 2010)X
First Amendment to the Amendment and Restatement of Master Trust Agreement for the DTE Energy Company Master Plan Trust between DTE Energy Corporate Services, LLC and DTE Energy Investment Committee and JP Morgan Chase Bank, N.A., dated as of March 13, 2013 (Exhibit 99-55 to DTE Energy’s Form 10-K for the year end December 13, 2013)X
Second Amendment to the Amendment and Restatement of Master Trust Agreement for the DTE Energy Company Master Plan Trust between DTE Energy Corporate Services, LLC and DTE Energy Investment Committee and JP Morgan Chase Bank, N.A., dated as of September 30, 2013 (Exhibit 99-56 to DTE Energy’s Form 10-K for the year ended December 31, 2013)X
Third Amendment to the Amendment and Restatement of Master Trust Agreement for the DTE Energy Company Master Plan Trust between DTE Energy Corporate Services, LLC and DTE Energy Investment Committee and JP Morgan Chase Bank, N.A., dated as of October 3, 2014 (Exhibit 99-57 to DTE Energy’s Form 10-Q for the quarter ended September 30, 2014)X
2015)

143



Fourth Amendment to the Amendment and Restatement of Master Trust Agreement for the DTE Energy Company Master Plan Trust between DTE Energy Corporate Services, LLC and DTE Energy Investment Committee and JP Morgan Chase Bank, N.A. dated as of November 28, 2014 (Exhibit 99-58 to DTE Energy’s Form 10-Q for the quarter ended September 30, 2015)X
Fifth Amendment to the Amendment and Restatement of Master Trust Agreement for the DTE Energy Company Master Plan Trust between DTE Energy Corporate Services, LLC and DTE Energy Investment Committee and Great-West Trust Company, LLC dated as of August 7, 2015 (Exhibit 99-59 to DTE Energy’s Form 10-Q for the quarter ended September 30, 2015) X  

144



Item 16. Form 10-K Summary
None.



DTE Energy Company
Schedule II — Valuation and Qualifying Accounts
Year Ending December 31,Year Ending December 31,
2015 2014 20132018 2017 2016
(In millions)(In millions)
Allowance for Doubtful Accounts (shown as deduction from Accounts receivable in DTE Energy's Consolidated Statements of Financial Position)          
Balance at Beginning of Period$54
 $55
 $62
$49
 $41
 $49
Additions:          
Charged to costs and expenses93
 95
 94
140
 80
 78
Charged to other accounts (a)14
 20
 23
55
 26
 18
Deductions (b)(112) (116) (124)(153) (98) (104)
Balance at End of Period$49
 $54
 $55
$91
 $49
 $41

(a)Collection of accounts previously written off.
(b)Uncollectible accounts written off.

DTE Electric Company
Schedule II — Valuation and Qualifying Accounts
Year Ending December 31,Year Ending December 31,
2015 2014 20132018 2017 2016
(In millions)(In millions)
Allowance for Doubtful Accounts (shown as deduction from Accounts receivable in DTE Electric's Consolidated Statements of Financial Position)          
Balance at Beginning of Period$29
 $28
 $35
$31
 $25
 $28
Additions: 
  
  
 
  
  
Charged to costs and expenses51
 50
 52
85
 55
 49
Charged to other accounts (a)6
 10
 11
36
 14
 8
Deductions (b)(58) (59) (70)(99) (63) (60)
Balance at End of Period$28
 $29
 $28
$53
 $31
 $25

(a)Collection of accounts previously written off.
(b)Uncollectible accounts written off.

145




Signatures
Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, DTE Energy Company has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.
  DTE ENERGY COMPANY
  (Registrant)
   
   
 By: /S/  GERARD M. ANDERSON
  Gerard M. Anderson
Chairman of the Board and
Chief Executive Officer
Date: February 10, 20167, 2019
Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of DTE Energy Company and in the capacities and on the date indicated.
By:/S/  GERARD M. ANDERSON By:/S/  PETER B. OLEKSIAK
 Gerard M. Anderson
Chairman of the Board,
Chief Executive Officer, and Director
(Principal Executive Officer)
  Peter B. Oleksiak
Senior Vice President and
Chief Financial Officer
(Principal Financial Officer)
     
By:/S/  DONNA M. ENGLANDJEFFREY A. JEWELL By:/S/  JAMES B. NICHOLSONRUTH G. SHAW
 Donna M. EnglandJeffrey A. Jewell
Vice President, Controller, and Chief Accounting Officer
(Principal Accounting Officer)
  James B. Nicholson,Ruth G. Shaw, Director
     
By:/S/  DAVID A. BRANDON By:/S/ CHARLES W. PRYOR,ROBERT C. SKAGGS, JR.
 David A. Brandon, Director  Charles W. Pryor,Robert C. Skaggs, Jr., Director
     
By:/S/  W. FRANK FOUNTAIN, JR. By:/S/  JOSUE ROBLES, JR.DAVID A. THOMAS
 W. Frank Fountain, Jr., Director  Josue Robles, Jr.,David A. Thomas, Director
     
By:/S/  CHARLES G. MCCLURE JR. By:/S/  RUTH G. SHAWJAMES H. VANDENBERGHE
 Charles G. McClure Jr., Director  Ruth G. Shaw,James H. Vandenberghe, Director
     
By:/S/  GAIL J. MCGOVERN By:/S/  DAVID A. THOMASVALERIE M. WILLIAMS
 Gail J. McGovern, Director  David A. Thomas,Valerie M. Williams, Director
     
By:/S/  MARK A. MURRAY By:/S/  JAMES H. VANDENBERGHE
 Mark A. Murray, Director  
By:/S/  JAMES B. NICHOLSON
James H. Vandenberghe,B. Nicholson, Director
Date: February 10, 20167, 2019

146




Signatures
Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, DTE Electric Company has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.
  DTE ELECTRIC COMPANY
  (Registrant)
   
   
 By:/S/  GERARD M. ANDERSON
  Gerard M. Anderson
Chairman of the Board and
Chief Executive Officer
Date: February 10, 20167, 2019
Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of DTE Electric Company and in the capacities and on the date indicated.
By:/S/  GERARD M. ANDERSON By:/S/  PETER B. OLEKSIAK
 
Gerard M. Anderson

Chairman of the Board,

Chief Executive Officer, and Director

(Principal Executive Officer)
  Peter B. Oleksiak
Senior Vice President, and
Chief Financial Officer, and Director
(Principal Financial Officer)
     
By:/S/  DONNA M. ENGLANDJEFFREY A. JEWELL By:/S/  LISA A. MUSCHONGBRUCE D. PETERSON
 
Donna M. EnglandJeffrey A. Jewell
Vice President, Controller, and Chief Accounting Officer
(Principal Accounting Officer)
  Lisa A. Muschong,Bruce D. Peterson, Director
     
By:/S/  DAVID E. MEADORLISA A. MUSCHONG By:/S/  BRUCE D. PETERSON
 David E. Meador,Lisa A. Muschong, Director  Bruce D. Peterson, Director
Date: February 10, 20167, 2019
Supplemental Information to be Furnished Withwith Reports Filed Pursuant to Section 15(d) of the Securities Exchange Act of 1934 by Registrants Which Have Not Registered Securities Pursuant to Section 12 of the Securities Exchange Act of 1934.
No annual report, proxy statement, form of proxy, or other proxy soliciting material has been sent to security holders of DTE Electric Company during the period covered by this Annual Report on Form 10-K for the fiscal year ended December 31, 2015.2018.


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