Document and Entity Information
Document and Entity Information Document - USD ($) | 12 Months Ended | |
Dec. 31, 2016 | Feb. 22, 2017 | |
Entity Information [Line Items] | ||
Entity Registrant Name | Transcontinental Gas Pipe Line Company, LLC | |
Entity Central Index Key | 99,250 | |
Document Type | 10-K | |
Document Period End Date | Dec. 31, 2016 | |
Amendment Flag | false | |
Document Fiscal Year Focus | 2,016 | |
Document Fiscal Period Focus | FY | |
Current Fiscal Year End Date | --12-31 | |
Entity Filer Category | Non-accelerated Filer | |
Entity Common Stock, Shares Outstanding | 0 | |
Entity Well-known Seasoned Issuer | No | |
Entity Voluntary Filers | No | |
Entity Current Reporting Status | Yes | |
Entity Public Float | $ 0 |
Consolidated Statement of Compr
Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | |
Operating Revenues: | |||
Natural gas sales | $ 86,720 | $ 125,774 | $ 121,397 |
Natural gas transportation | 1,397,341 | 1,318,656 | 1,166,244 |
Natural gas storage | 122,555 | 137,983 | 140,344 |
Other | 9,519 | 10,106 | 5,152 |
Total operating revenues | 1,616,135 | 1,592,519 | 1,433,137 |
Operating Costs and Expenses: | |||
Cost of natural gas sales | 86,720 | 125,774 | 121,397 |
Cost of natural gas transportation | 19,689 | 26,501 | 31,629 |
Operation and maintenance | 316,989 | 288,386 | 271,603 |
Administrative and general | 168,759 | 179,489 | 183,760 |
Depreciation and amortization | 307,707 | 277,850 | 270,181 |
Taxes - other than income taxes | 60,119 | 49,567 | 44,521 |
Other expense, net | 57,064 | 57,800 | 37,208 |
Total operating costs and expenses | 1,017,047 | 1,005,367 | 960,299 |
Operating Income | 599,088 | 587,152 | 472,838 |
Other (Income) and Other Expenses: | |||
Interest expense - affiliate | 60 | 64 | 70 |
Interest expense - other | 151,234 | 82,774 | 84,917 |
Interest income - affiliate | (2,201) | (28) | (49) |
Interest income - other | (2,185) | (1,933) | (1,782) |
Allowance for equity and borrowed funds used during construction (AFUDC) | (68,964) | (63,072) | (25,046) |
Equity in earnings of unconsolidated affiliates | (5,914) | (5,593) | (5,783) |
Miscellaneous other (income) expenses, net | 3,683 | (517) | (2,373) |
Total other (income) and other expenses | 75,713 | 11,695 | 49,954 |
Net Income | 523,375 | 575,457 | 422,884 |
Other comprehensive income: | |||
Equity interest in unrealized gain on interest rate hedges (includes $167, $316, and $344 for the years ended December 31, 2016, 2015, and 2014, respectively, of accumulated other comprehensive income reclassification for equity interest in realized losses on interest rate hedges) | 41 | 84 | 143 |
Comprehensive Income | $ 523,416 | $ 575,541 | $ 423,027 |
Consolidated Statement of Comp3
Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | |
Income Statement [Abstract] | |||
Accumulated other comprehensive income reclassification for realized losses on interest rate hedges | $ 167 | $ 316 | $ 344 |
Consolidated Balance Sheet
Consolidated Balance Sheet - USD ($) $ in Thousands | Dec. 31, 2016 | Dec. 31, 2015 |
Current Assets: | ||
Cash | $ 0 | $ 0 |
Receivables: | ||
Trade, less allowance of $0 ($13 in 2015) | 141,726 | 134,834 |
Affiliates | 489 | 1,084 |
Advances to affiliate | 811,693 | 64,608 |
Other | 2,589 | 15,422 |
Transportation and exchange gas receivables | 1,827 | 2,427 |
Inventories: | ||
Gas in storage, at original cost | 786 | 780 |
Gas available for customer nomination, at average cost | 17,233 | 19,838 |
Materials and supplies, at lower of average cost or market | 37,190 | 36,223 |
Regulatory assets | 87,059 | 79,575 |
Other | 13,305 | 15,297 |
Total current assets | 1,113,897 | 370,088 |
Investments, at cost plus equity in undistributed earnings | 42,403 | 45,078 |
Property, Plant and Equipment: | ||
Natural gas transmission plant | 11,996,454 | 10,863,944 |
Less-Accumulated depreciation and amortization | 3,687,473 | 3,471,775 |
Total property, plant and equipment, net | 8,308,981 | 7,392,169 |
Other Assets: | ||
Regulatory assets | 264,001 | 263,730 |
Other | 102,198 | 73,814 |
Total other assets | 366,199 | 337,544 |
Total assets | 9,831,480 | 8,144,879 |
Payables: | ||
Trade | 211,829 | 194,081 |
Affiliates | 29,455 | 38,243 |
Cash overdrafts | 40,043 | 28,969 |
Transportation and exchange gas payables | 1,571 | 1,355 |
Accrued liabilities: | ||
Property and other taxes | 13,594 | 12,661 |
Interest | 49,900 | 19,894 |
Regulatory liabilities | 9,120 | 3,536 |
Customer deposits | 47,049 | 12,778 |
Customer advances | 34,923 | 20,999 |
Asset retirement obligations | 26,934 | 23,192 |
Other | 16,177 | 16,170 |
Total current liabilities | 480,595 | 371,878 |
Long-Term Debt | 2,210,754 | 1,419,574 |
Other Long-Term Liabilities: | ||
Asset retirement obligations | 248,518 | 299,834 |
Regulatory liabilities | 449,391 | 382,325 |
Advances for construction costs | 283,028 | 97,790 |
Transportation prepayments | 11,837 | 12,806 |
Other | 6,088 | 4,819 |
Total other long-term liabilities | 998,862 | 797,574 |
Contingent Liabilities and Commitments (Note 2) | ||
Owner's Equity: | ||
Member's capital | 3,678,499 | 3,176,499 |
Retained earnings | 2,462,760 | 2,379,385 |
Accumulated other comprehensive loss | 10 | (31) |
Total owner's equity | 6,141,269 | 5,555,853 |
Total liabilities and owner's equity | $ 9,831,480 | $ 8,144,879 |
Consolidated Balance Sheet Cons
Consolidated Balance Sheet Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Thousands | Dec. 31, 2016 | Dec. 31, 2015 |
Statement of Financial Position [Abstract] | ||
Allowance for receivables | $ 0 | $ 13 |
Consolidated Statement of Owner
Consolidated Statement of Owner's Equity Consolidated Statement of Owner's Equity - USD ($) $ in Thousands | Total | Member's Capital | Retained Earnings | Accumulated Other Comprehensive Income (Loss) |
Balance at beginning of period at Dec. 31, 2013 | $ 2,257,499 | $ 2,328,044 | $ (258) | |
Cash contributions from parent | $ 267,000 | 267,000 | ||
Net income | 422,884 | 422,884 | ||
Cash distributions to parent | (411,000) | (411,000) | ||
Equity interest in unrealized gain on interest rate hedge | 143 | 143 | ||
Balance at end of period at Dec. 31, 2014 | 4,864,312 | 2,524,499 | 2,339,928 | (115) |
Cash contributions from parent | 652,000 | 652,000 | ||
Net income | 575,457 | 575,457 | ||
Cash distributions to parent | (536,000) | (536,000) | ||
Equity interest in unrealized gain on interest rate hedge | 84 | 84 | ||
Balance at end of period at Dec. 31, 2015 | 5,555,853 | 3,176,499 | 2,379,385 | (31) |
Cash contributions from parent | 502,000 | 502,000 | ||
Net income | 523,375 | 523,375 | ||
Cash distributions to parent | (440,000) | (440,000) | ||
Equity interest in unrealized gain on interest rate hedge | 41 | 41 | ||
Balance at end of period at Dec. 31, 2016 | $ 6,141,269 | $ 3,678,499 | $ 2,462,760 | $ 10 |
Consolidated Statement of Cash
Consolidated Statement of Cash Flows - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | |
Cash flows from operating activities: | |||
Net income | $ 523,375 | $ 575,457 | $ 422,884 |
Adjustments to reconcile net income to net cash provided by operating activities: | |||
Depreciation and amortization | 307,707 | 277,850 | 269,395 |
Allowance for equity funds used during construction (equity AFUDC) | (56,468) | (48,435) | (18,701) |
Changes in operating assets and liabilities: | |||
Receivables - affiliates | 595 | (430) | 1,947 |
Receivables - trade and other | 5,941 | (19,521) | 17,437 |
Transportation and exchange gas receivable | 600 | 1,058 | 3,272 |
Regulatory assets - current | (7,484) | (1,765) | (40,290) |
Regulatory assets - non-current | (271) | (24,650) | 17,532 |
Inventories | 1,632 | 9,858 | (19,167) |
Payables - affiliates | (10,909) | 2,676 | 9,420 |
Payables - trade | 29,375 | (2,077) | 32,618 |
Accrued liabilities | 74,759 | (10,015) | (39,450) |
Asset retirement obligations - non-current | 31,114 | 19,022 | 30,840 |
Asset retirement obligation - removal costs | (4,911) | (3,097) | (12,824) |
Reserve for rate refunds | 0 | 0 | (98,217) |
Other, net | 32,030 | 45,007 | 7,954 |
Net cash provided by operating activities | 927,085 | 820,938 | 584,650 |
Cash flows from financing activities: | |||
Proceeds from long-term debt | 998,250 | 0 | 0 |
Retirement of long-term debt | 200,000 | 0 | 0 |
Payments of debt issuance costs | 8,381 | 0 | 0 |
Cash distributions to parent | (440,000) | (536,000) | (411,000) |
Cash contributions from parent | 502,000 | 652,000 | 267,000 |
Other, net | 0 | 0 | 22,329 |
Net cash provided by (used in) financing activities | 851,869 | 116,000 | (121,671) |
Cash flows from investing activities: | |||
Property, plant and equipment additions, net of equity AFUDC | (1,213,969) | (1,270,860) | (724,163) |
Contributions and Advances for Construction Costs | 216,447 | 85,901 | 57,817 |
Disposal of property, plant and equipment, net | (12,529) | (12,358) | (7,532) |
Advances to affiliate, net | (747,085) | 242,302 | 219,470 |
Return of capital from unconsolidated affiliates | 2,767 | 2,015 | 2,333 |
Purchase of ARO Trust investments | (70,901) | (64,087) | (52,038) |
Proceeds from sale of ARO Trust investments | 44,195 | 43,284 | 38,691 |
Proceeds from insurance | 2,121 | 35,132 | 0 |
Other, net | 0 | 1,560 | 2,503 |
Net cash used in investing activities | (1,778,954) | (937,111) | (462,919) |
Increase (decrease) in cash | 0 | (173) | 60 |
Cash at beginning of period | 0 | 173 | 113 |
Cash at end of period | 0 | 0 | 173 |
Increase to property, plant and equipment, net of equity AFUDC | (1,200,696) | (1,222,292) | (807,232) |
Changes in related accounts payable and accrued liabilities | (13,273) | (48,568) | 83,069 |
Property, plant and equipment additions, net of equity AFUDC | (1,213,969) | (1,270,860) | (724,163) |
Supplemental Cash Flow Elements [Abstract] | |||
Interest (exclusive of amount capitalized) | 103,391 | 66,489 | 77,304 |
Income taxes | $ 828 | $ 1,161 | $ 864 |
Summary of Significant Accounti
Summary of Significant Accounting Policies (Notes) | 12 Months Ended |
Dec. 31, 2016 | |
Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
Summary of Significant Accounting Policies | SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Corporate Structure and Control In this report, Transco (which includes Transcontinental Gas Pipe Line Company, LLC and, unless the context otherwise requires, all of our majority-owned subsidiaries) is at times referred to in the first person as “we,” “us” or “our.” Transco is indirectly owned by Williams Partners L.P. (WPZ), a publicly traded Delaware limited partnership, which is consolidated by The Williams Companies, Inc. (Williams). On February 2, 2015, WPZ was merged into Access Midstream Partners, L.P. (ACMP), another publicly traded limited partnership consolidated by Williams. ACMP was the surviving partnership and was subsequently renamed Williams Partners, L.P. At December 31, 2016, Williams owned an approximate 60 percent interest in WPZ, comprised of an approximate 58 percent limited partner interest and all of the 2 percent general partner interest. In January 2017, Williams permanently waived the WPZ general partner's incentive distribution rights, converted its 2 percent general partner interest in WPZ to a non-economic interest and purchased additional WPZ common units. Following these transactions, Williams owns a 74 percent limited partner interest in WPZ. Transco is a single member limited liability company, and as such, single member losses are limited to the amount of its investment. Related Party Transaction A former member of Williams' Board of Directors, who was elected in 2013 and resigned during 2016, is also the current chairman, president, and chief executive officer of Public Service Enterprise Group, an energy services company that is a customer of ours. This board member does not have any material interest in any transactions between the energy services company and us and he had no role in any such transactions. (See Note 7.) Nature of Operations We are an interstate natural gas transmission company that owns a natural gas pipeline system extending from Texas, Louisiana, Mississippi and the Gulf of Mexico through Alabama, Georgia, South Carolina, North Carolina, Virginia, Maryland, Delaware, Pennsylvania and New Jersey to the New York City metropolitan area. The system serves customers in Texas and the 12 southeast and Atlantic seaboard states mentioned above, including major metropolitan areas in Georgia, Washington D.C., Maryland, North Carolina, New York, New Jersey and Pennsylvania. Regulatory Accounting We are regulated by the Federal Energy Regulatory Commission (FERC). The Accounting Standards Codification (ASC) Regulated Operations (Topic 980), provides that rate-regulated public utilities account for and report regulatory assets and liabilities consistent with the economic effect of the way in which regulators establish rates if the rates established are designed to recover the costs of providing the regulated service and if the competitive environment makes it probable that such rates can be charged and collected. Accounting for businesses that are regulated and apply the provisions of Topic 980 can differ from the accounting requirements for non-regulated businesses. Transactions that are recorded differently as a result of regulatory accounting requirements include the capitalization of an equity return component on regulated capital projects, capitalization of other project costs, retirements of general plant assets, employee related benefits, environmental costs, negative salvage, asset retirement obligations, and other costs and taxes included in, or expected to be included in, future rates. As a rate-regulated entity, our management has determined that it is appropriate to apply the accounting prescribed by Topic 980 and, accordingly, the accompanying consolidated financial statements include the effects of the types of transactions described above that result from regulatory accounting requirements. Basis of Presentation Williams’ acquisition of Transco Energy Company and its subsidiaries, including us, in 1995 was accounted for using the purchase method of accounting. Accordingly, an allocation of the purchase price was assigned to our assets and liabilities based on their estimated fair values. The purchase price allocation to us primarily consisted of a $1.5 billion allocation to property, plant and equipment and adjustments to deferred taxes based upon the book basis of the net assets recorded as a result of the acquisition. The amount allocated to property, plant and equipment is being depreciated on a straight-line basis over 40 years, the estimated useful lives of these assets at the date of acquisition, at approximately $35 million per year. At December 31, 2016 , the remaining property, plant and equipment allocation was approximately $0.6 billion. Current FERC policy does not permit us to recover through rates amounts in excess of original cost. Principles of Consolidation The consolidated financial statements include our accounts and the accounts of the subsidiaries we control. Companies in which we and our subsidiaries own 20 percent to 50 percent of the voting common stock or otherwise exercise significant influence over operating and financial policies of the company are accounted for under the equity method. The equity method investments as of December 31, 2016 and December 31, 2015 consist of Cardinal Pipeline Company, LLC (Cardinal) with ownership interest of approximately 45 percent and Pine Needle LNG Company, LLC (Pine Needle) with ownership interest of 35 percent. We received distributions associated with our equity method investments totaling $8.6 million, $7.6 million, and $9.1 million in 2016 , 2015 and 2014 , respectively. Included in the distributions are $2.8 million, $2.0 million and $2.3 million return of capital in 2016, 2015 and 2014, respectively. Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. Estimates and assumptions which, in the opinion of management, are significant to the underlying amounts included in the financial statements and for which it would be reasonably possible that future events or information could change those estimates include: 1) revenues subject to refund; 2) litigation-related contingencies; 3) environmental remediation obligations; 4) impairment assessments of long-lived assets; 5) depreciation; and 6) asset retirement obligations. Revenue Recognition Revenues for transportation of gas under long-term firm agreements are recognized considering separately the reservation and commodity charges. Reservation revenues are recognized monthly over the term of the agreement regardless of the volume of natural gas transported. Commodity revenues from both firm and interruptible transportation are recognized in the period transportation services are provided based on volumes of natural gas physically delivered at the agreed upon delivery point. Revenues for the storage of gas under firm agreements are recognized considering separately the reservation, capacity, and injection and withdrawal charges. Reservation and capacity revenues are recognized monthly over the term of the agreement regardless of the volume of storage service actually utilized. Injection and withdrawal revenues are recognized in the period when volumes of natural gas are physically injected into or withdrawn from storage. In the course of providing transportation services to customers, we may receive different quantities of gas from shippers than the quantities delivered on behalf of those shippers. The resulting imbalances are primarily settled through the purchase and sale of gas with our customers under terms provided in our FERC tariff. Revenue is recognized from the sale of gas upon settlement of the transportation and exchange imbalances (See Gas Imbalances in this Note). As a result of the ratemaking process, certain revenues collected by us may be subject to refunds upon the issuance of final orders by the FERC in pending rate proceedings. We record estimates of rate refund liabilities considering our and other third-party regulatory proceedings, advice of counsel and other risks. Environmental Matters We are subject to federal, state, and local environmental laws and regulations. Environmental expenditures are expensed or capitalized depending on their economic benefit and potential for rate recovery. We believe that any expenditures required to meet applicable environmental laws and regulations are prudently incurred in the ordinary course of business and such expenditures would be permitted to be recovered through rates. Property, Plant and Equipment Property, plant and equipment is recorded at cost. The carrying values of these assets are also based on estimates, assumptions and judgments relative to capitalized costs, useful lives and salvage values. These estimates, assumptions and judgments reflect FERC regulations, as well as historical experience and expectations regarding future industry conditions and operations. The FERC identifies installation, construction and replacement costs that are to be capitalized. All other costs are expensed as incurred. Gains or losses from the ordinary sale or retirement of property, plant and equipment are credited or charged to accumulated depreciation; certain other gains or losses are recorded in operating income. We provide for depreciation under the composite (group) method at straight-line FERC prescribed rates that are applied to the cost of the group for transmission facilities, production and gathering facilities and storage facilities. Under this method, assets with similar lives and characteristics are grouped and depreciated as one asset. Included in our depreciation rates is a negative salvage component (net cost of removal) that we currently collect in rates. Our depreciation rates are subject to change each time we file a general rate case with the FERC. Depreciation rates used for major regulated gas plant facilities at December 31, 2016 , 2015 and 2014 are as follows: Category of Property 2016-2014 Gathering facilities 1.35% - 2.50% Storage facilities 2.10% - 2.25% Onshore transmission facilities 2.61% - 5.00% Offshore transmission facilities 1.20% - 1.20% We record a liability and increase the basis in the underlying asset for the present value of each expected future asset retirement obligation (ARO) at the time the liability is initially incurred, typically when the asset is acquired or constructed. Measurements of AROs include, as a component of future expected costs, an estimate of the price that a third party would demand, and could expect to receive, for bearing the uncertainties inherent in the obligations, sometimes referred to as a market-risk premium. The ARO asset is depreciated in a manner consistent with the expected timing of the future abandonment of the underlying physical assets. We measure changes in the liability due to passage of time by applying an interest method of allocation. The depreciation of the ARO asset and accretion of the ARO liability are recognized as an increase to a regulatory asset, as management expects to recover such amounts in future rates. The regulatory asset is amortized commensurate with our collection of these costs in rates. Impairment of Long-lived Assets We evaluate the long lived assets of identifiable business activities for impairment when events or changes in circumstances indicate, in our management’s judgment, that the carrying value of such assets may not be recoverable. When an indicator of a potential impairment has occurred we compare our management’s estimate of undiscounted future cash flows attributable to the assets to the carrying value of the assets to determine whether an impairment has occurred. We apply a probability-weighted approach to consider the likelihood of different cash flow assumptions and possible outcomes including selling in the near term or holding for the remaining estimated useful life. If an impairment of the carrying value has occurred, we determine the amount of the impairment recognized in the financial statements by estimating the fair value of the assets and recording a loss for the amount that the carrying value exceeds the estimated fair value. For assets identified to be disposed of in the future and considered held for sale in accordance with the ASC Property, Plant, and Equipment (Topic 360), we compare the carrying value to the estimated fair value less the cost to sell to determine if recognition of an impairment is required. Until the assets are disposed of, the estimated fair value, which includes estimated cash flows from operations until the assumed date of sale, is recalculated when related events or circumstances change. Judgments and assumptions are inherent in our management’s estimate of undiscounted future cash flows used to determine recoverability of an asset and the estimate of an asset’s fair value used to calculate the amount of impairment to recognize. Allowance for Funds Used During Construction Allowance for funds used during construction (AFUDC) represents the estimated cost of borrowed and equity funds applicable to utility plant in process of construction and are included as a cost of property, plant and equipment because it constitutes an actual cost of construction under established regulatory practices. The FERC has prescribed a formula to be used in computing separate allowances for borrowed and equity AFUDC. The allowance for borrowed funds used during construction was $12.5 million, $14.6 million and $6.3 million, for 2016 , 2015 and 2014 , respectively. The allowance for equity funds was $56.5 million, $48.4 million, and $18.7 million, for 2016 , 2015 and 2014 , respectively. Income Taxes We generally are not a taxable entity for federal or state and local income tax purposes. The tax on net income is generally borne by unitholders of our ultimate parent, WPZ. Net income for financial statement purposes may differ significantly from taxable income of WPZ’s unitholders as a result of differences between the tax basis and financial reporting basis of assets and liabilities and the taxable income allocation requirements under the WPZ partnership agreement. The aggregated difference in the basis of our assets for financial and tax reporting purposes cannot be readily determined because information regarding each of WPZ’s unitholder’s tax attributes in WPZ is not available to us. Accounts Receivable and Allowance for Doubtful Receivables Accounts receivable are stated at the historical carrying amount net of reserves or write-offs. Our credit risk exposure in the event of nonperformance by the other parties is limited to the face value of the receivables. We perform ongoing credit evaluations of our customers’ financial condition and require collateral from our customers, if necessary. Due to our customer base, we have not historically experienced recurring credit losses in connection with our receivables. Receivables determined to be uncollectible are reserved or written off in the period of determination. Gas Imbalances In the course of providing transportation services to customers, we may receive different quantities of gas from shippers than the quantities delivered on behalf of those shippers. Additionally, we transport gas on various pipeline systems which may deliver different quantities of gas on behalf of us than the quantities of gas received from us. These transactions result in gas transportation and exchange imbalance receivables and payables which are recovered or repaid in cash or through the receipt or delivery of gas in the future and are recorded in the accompanying Consolidated Balance Sheet. Settlement of imbalances requires agreement between the pipelines and shippers as to allocations of volumes to specific transportation contracts and timing of delivery of gas based on operational conditions. Our tariff includes a method whereby most transportation imbalances are settled on a monthly basis. Each month a portion of the imbalances are not identified to specific parties and remain unsettled. These are generally identified to specific parties and settled in subsequent periods. We believe that amounts that remain unidentified to specific parties and unsettled at year end are valid balances that will be settled with no material adverse effect upon our financial position, results of operations or cash flows. Management has implemented a policy of continuing to carry any unidentified transportation and exchange imbalances on the books for a three-year period. At the end of the three year period a final assessment will be made of their continued validity. Absent a valid reason for maintaining the imbalance, any remaining balance will be recognized in income. Certain imbalances are being recovered or repaid in cash or through the receipt or delivery of gas upon agreement of the parties as to the allocation of the gas volumes, and as permitted by pipeline operating conditions. These imbalances have been classified as current assets and current liabilities at December 31, 2016 and 2015. We utilize the average cost method of accounting for gas imbalances. Deferred Cash Out Most transportation imbalances are settled in cash on a monthly basis (cash out). We are required by our tariff to refund revenues received from the cash out of transportation imbalances in excess of costs incurred during the annual August through July reporting period. Revenues received in excess of costs incurred are deferred until refunded in accordance with the tariff. Gas Inventory We utilize the last-in, first-out (LIFO) method of accounting for inventory gas in storage. At December 31, 2016 and 2015, Gas in Storage, at LIFO, was zero. The basis for determining current cost at the end of each year is the December monthly average gas price delivered to pipelines in Texas and Louisiana. We utilize the average cost method of accounting for gas available for customer nomination. Liquefied natural gas in storage is valued at original cost. Materials and Supplies Inventory All inventories are stated at lower of average cost or market. We perform an annual review of Materials and Supplies inventories, including a quarterly analysis of parts that may no longer be useful due to planned replacements of compressor engines and other components on our system. Based on this assessment, we record a reserve for the value of the inventory which can no longer be used for maintenance and repairs on our pipeline. There was a minimal reserve at December 31, 2016 and 2015. Contingent Liabilities We record liabilities for estimated loss contingencies, including environmental matters, when we assess that a loss is probable and the amount of the loss can be reasonably estimated. These liabilities are calculated based upon our assumptions and estimates with respect to the likelihood or amount of loss and upon advice of legal counsel, engineers, or other third parties regarding the probable outcomes of the matters. These calculations are made without consideration of any potential recovery from third-parties. We recognize insurance recoveries or reimbursements from others when realizable. Revisions to these liabilities are generally reflected in income when new or different facts or information become known or circumstances change that affect the previous assumptions or estimates. Pension and Other Postretirement Benefits We do not have employees. Certain of the costs charged to us by Williams associated with employees who directly support us include costs related to Williams’ pension and other postretirement benefit plans. (See Note 6.) Although the underlying benefit plans of Williams are single-employer plans, we follow multiemployer plan accounting whereby the amount charged to us and thus paid by us, is based on our share of net periodic benefit cost. Cash Flows from Operating Activities and Cash Equivalents We use the indirect method to report cash flows from operating activities, which requires adjustments to net income to reconcile to net cash flows provided by operating activities. We include short-term, highly-liquid investments that have an original maturity of three months or less as cash equivalents. Accounting Standards Issued But Not Yet Adopted In August 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-15 “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments” (ASU 2016-15). ASU 2016-15 provides specific guidance on eight cash flow classification issues, including debt prepayment or debt extinguishment costs and distributions received from equity method investees, to reduce diversity in practice. ASU 2016-15 is effective for interim and annual periods beginning after December 15, 2017. Early adoption is permitted. ASU 2016-15 requires a retrospective transition. We are evaluating the impact of ASU 2016-15 on our consolidated financial statements. In June 2016, the FASB issued ASU 2016-13 “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (ASU 2016-13). ASU 2016-13 changes the impairment model for most financial assets and certain other instruments. For trade and other receivables, held-to-maturity debt securities, loans, and other instruments, entities will be required to use a new forward-looking “expected loss” model that generally will result in the earlier recognition of allowances for losses. The guidance also requires increased disclosures. ASU 2016-13 is effective for interim and annual periods beginning after December 15, 2019. Early adoption is permitted. ASU 2016-13 requires varying transition methods for the different categories of amendments. We do not expect ASU 2016-13 to have a significant impact on our consolidated financial statements. In February 2016, the FASB issued ASU 2016-02 “Leases (Topic 842)” (ASU 2016-02). ASU 2016-02 establishes a comprehensive new lease accounting model. ASU 2016-02 clarifies the definition of a lease, requires a dual approach to lease classification similar to current lease classifications, and causes lessees to recognize leases on the balance sheet as a lease liability with a corresponding right-of-use asset. ASU 2016-02 is effective for interim and annual periods beginning after December 15, 2018. Early adoption is permitted. ASU 2016-02 requires a modified retrospective transition for capital or operating leases existing at or entered into after the beginning of the earliest comparative period presented in the financial statements. We are reviewing contracts to identify leases, particularly reviewing the applicability of ASU 2016-02 to contracts involving easements/rights-of-way. In May 2014, the FASB issued ASU 2014-09 establishing Accounting Standards Codification (ASC) Topic 606, “Revenue from Contracts with Customers” (ASC 606). ASC 606 establishes a comprehensive new revenue recognition model designed to depict the transfer of goods or services to a customer in an amount that reflects the consideration the entity expects to be entitled to receive in exchange for those goods or services and requires significantly enhanced revenue disclosures. In August 2015, the FASB issued ASU 2015-14 “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date” (ASU 2015-14). Per ASU 2015-14, the standard is effective for interim and annual reporting periods beginning after December 15, 2017. ASC 606 allows either full retrospective or modified retrospective transition and early adoption is permitted for annual periods beginning after December 15, 2016. We continue to evaluate the impact the standard may have on our financial statements. For each revenue contract type, we are conducting a formal contract review process to evaluate the impact, if any, that the new revenue standard may have. We have substantially completed that process, but continue to evaluate our accounting for noncash consideration, which exists in contracts where we receive commodities as full or partial consideration, and the accounting for contributions in aid of construction. As such, we are unable to determine the potential impact upon the amount and timing of revenue recognition and related disclosures. Additionally, we have identified possible financial system and internal control changes necessary for adoption. We currently anticipate utilizing a modified retrospective transition upon the adoption of ASC 606 as of January 1, 2018. |
Contingent Liabilities and Comm
Contingent Liabilities and Commitments (Notes) | 12 Months Ended |
Dec. 31, 2016 | |
Commitments and Contingencies Disclosure [Abstract] | |
Contingent Liabilities and Commitments | CONTINGENT LIABILITIES AND COMMITMENTS Rate Matters General rate case (Docket No. RP06-569) On August 31, 2006, we submitted to the FERC a general rate filing principally designed to recover increased costs. The rates became effective March 1, 2007, subject to refund and the outcome of a hearing. All issues in this proceeding except one have been resolved by settlement. The one issue reserved for litigation or further settlement relates to our proposal to change the design of the rates for service under our WSS-OA storage rate schedule, which was implemented subject to refund on March 1, 2007. Following a hearing, the FERC issued an opinion approving our proposed incremental rate design, and subsequently denied requests for rehearing of that approval. On February 21, 2014, the U. S. Court of Appeals for the D.C. Circuit (D.C. Circuit) issued an opinion that vacated and remanded the FERC's order because the FERC did not adequately support its conclusions. On March 17, 2016, the FERC issued an order addressing the issues raised by the D.C. Circuit's opinion. In the March 17 order, the FERC reversed its prior opinion and found that Transco's incremental rate design is unjust and unreasonable. The FERC directed Transco to design its WSS-OA rates on a rolled-in basis, to file revised WSS-OA rates reflecting the findings in the order, and to refund the amounts collected in excess of those rates since March 1, 2007. On April 18, 2016, we submitted the compliance filing reflecting rolled-in rates for WSS-OA service consistent with the March 17 order, and began charging those rates beginning April 19, 2016. We also filed a request for rehearing of the March 17 order. If we are unsuccessful, refunds will be due within 60 days after a final FERC order no longer subject to rehearing. As of December 31, 2016, we have accrued a liability for potential refunds of $18.7 million, consisting of a $15.3 million charge to revenue and $3.4 million of interest expense. Station 62 Incident On October 8, 2015, an explosion and fire occurred at our Compressor Station No. 62 in Gibson, Louisiana. At the time of the incident, planned facility maintenance was being performed at the station and the facility was not operational. The incident was related to maintenance work being performed on the slug catcher at the station. Four contractor employees were killed in the incident and others were injured. In responding to the incident, we cooperated with local, state and federal authorities, including the Louisiana State Police, Terrebonne Parish, the Louisiana Department of Environmental Quality, the U.S. Environmental Protection Agency (Region 6), the Occupational Safety and Health Administration, and the U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration (PHMSA). On July 29, 2016, PHMSA issued a Notice of Probable Violation (NOPV), which includes a $1.6 million proposed civil penalty to us in connection with the incident. This penalty was accrued in the second quarter of 2016 and would not be covered by our insurance policies. We filed a response to the NOPV on August 25, 2016. The incident did not cause any rupture of the gas pipeline or any damage to the building containing the compressor engines. In anticipation of the planned maintenance, our Southeast Louisiana Lateral was taken out of service on October 4, 2015, which affected approximately 200 MMcf/d of natural gas production. The lateral was restored to service in early 2016 after repairs were made to the facilities damaged in the incident. We are a defendant in lawsuits seeking damages for wrongful death, personal injury and property damages. We believe it is reasonably possible that losses will be incurred on some lawsuits. However, in management's judgment, the ultimate resolution of these matters will not have a material effect on our financial condition, results of operations or cash flows. While we also have claims for indemnification, we believe that it is probable that any ultimate losses incurred will be covered by our general liability insurance policy. Environmental Matters We have had studies underway for many years to test some of our facilities for the presence of toxic and hazardous substances such as polychlorinated biphenyls (PCBs) and mercury to determine to what extent, if any, remediation may be necessary. We have also similarly evaluated past on-site disposal of hydrocarbons at a number of our facilities. We have worked closely with and responded to data requests from the U.S. Environmental Protection Agency (EPA) and state agencies regarding such potential contamination of certain of our sites. On the basis of the findings to date, we estimate that environmental assessment and remediation costs under various federal and state statutes will total approximately $6 million to $8 million (including both expense and capital expenditures), measured on an undiscounted basis, and will substantially be spent over the next four to six years. This estimate depends on a number of assumptions concerning the scope of remediation that will be required at certain locations and the cost of the remedial measures. We are conducting environmental assessments and implementing a variety of remedial measures that may result in increases or decreases in the total estimated costs. At December 31, 2016 , we had a balance of approximately $4.2 million for the expense portion of these estimated costs recorded in current liabilities ($2.1 million) and other long-term liabilities ($2.1 million) in the accompanying Consolidated Balance Sheet. At December 31, 2015 , we had a balance of approximately $2.9 million for the expense portion of these estimated costs recorded in current liabilities ($1.4 million) and other long-term liabilities ($1.5 million) in the accompanying Consolidated Balance Sheet. We have been identified as a potentially responsible party (PRP) at various Superfund and state waste disposal sites. Based on present volumetric estimates and other factors, our estimated aggregate exposure for remediation of these sites is less than $0.5 million. The estimated remediation costs for all of these sites are included in the $6 million to $8 million range discussed above. Liability under the Comprehensive Environmental Response, Compensation and Liability Act and applicable state law can be joint and several with other PRPs. Although volumetric allocation is a factor in assessing liability, it is not necessarily determinative; thus, the ultimate liability could be substantially greater than the amounts described above. In March 2008, the EPA promulgated a new, lower National Ambient Air Quality Standard (NAAQS) for ground-level ozone. In May 2012, the EPA completed designation of new eight-hour ozone non-attainment areas. Several of our facilities are located in 2008 ozone non-attainment areas. To date, no federal actions have been proposed to mandate additional emission controls at these facilities. Pursuant to recently finalized state regulatory actions associated with implementation of the 2008 ozone standard, we anticipate that some facilities may be subject to increased controls within five years. As a result, the cost of additions to property, plant, and equipment is expected to increase. We are unable at this time to estimate with any certainty the cost of additions that may be required to meet the proposed regulations. In December 2014, the EPA proposed to further reduce the ground-level ozone NAAQS from the March 2008 levels and subsequently finalized a rule on October 1, 2015. We are monitoring the rule's implementation as the reduction will trigger additional federal and state regulatory actions that may impact our operations. As a result, the cost of additions to property, plant and equipment is expected to increase. We are unable at this time to estimate with any certainty the cost of additions that may be required to meet new regulations. On January 22, 2010, the EPA set a new one-hour nitrogen dioxide (NO 2 ) NAAQS. The effective date of the new NO 2 standard was April 12, 2010. On January 20, 2012, the EPA determined pursuant to available information that no area in the country is violating the 2010 NO 2 NAAQS and thus designated all areas of the country as “unclassifiable/attainment.” Also, at that time, the EPA noted its plan to deploy an expanded NO 2 monitoring network beginning in 2013. However, on October 5, 2012, the EPA proposed a graduated implementation of the monitoring network between January 1, 2014 and January 1, 2017. Once three years of data is collected from the new monitoring network, the EPA will reassess attainment status with the one-hour NO 2 NAAQS. Until that time, the EPA or states may require ambient air quality modeling on a case by case basis to demonstrate compliance with the NO 2 standard. Because we are unable to predict the outcome of the EPA’s or states’ future assessment using the new monitoring network, we are unable to estimate the cost of additions that may be required to meet this regulation. We consider prudently incurred environmental assessment and remediation costs and the costs associated with compliance with environmental standards to be recoverable through rates. To date, we have been permitted recovery of environmental costs, and it is our intent to continue seeking recovery of such costs through future rate filings. As a result, as estimated costs of environmental assessment and remediation are incurred, they are recorded as regulatory assets in the Consolidated Balance Sheet until collected through rates. At December 31, 2016, we had a balance of approximately $2.5 million of uncollected environmental related regulatory assets recorded in current assets ($1.2 million) and other assets ($1.3 million) in the accompanying Consolidated Balance Sheet. At December 31, 2015, we had a balance of approximately $1.6 million of uncollected environmental related regulatory assets recorded in current assets ($1.2 million) and other assets ($0.4 million) in the accompanying Consolidated Balance Sheet. Other Matters Various other proceedings are pending against us and are considered incidental to our operations. Summary We estimate that for all matters for which we are able to reasonably estimate a range of loss, including those noted above and others that are not individually significant, our aggregate reasonably possible losses beyond amounts accrued for all of our contingent liabilities are immaterial to our expected future annual results of operations, liquidity and financial position. These calculations have been made without consideration of any potential recovery from third parties. We have disclosed all significant matters for which we are unable to reasonably estimate a range of possible loss. Other Commitments Commitments for construction We have commitments for construction and acquisition of property, plant and equipment of approximately $84 million at December 31, 2016 . |
Debt, Financing Arrangements an
Debt, Financing Arrangements and Leases (Notes) | 12 Months Ended |
Dec. 31, 2016 | |
Debt Disclosure [Abstract] | |
Debt, Financing Arrangements and Leases | DEBT, FINANCING ARRANGEMENTS AND LEASES Long-Term Debt At December 31, 2016 and 2015 , long-term debt issues were outstanding as follows (in thousands): 2016 2015 Debentures: 7.08% due 2026 $ 7,500 $ 7,500 7.25% due 2026 200,000 200,000 Total debentures 207,500 207,500 Notes: 6.4% due 2016 — 200,000 6.05% due 2018 250,000 250,000 7.85% due 2026 1,000,000 — 5.4% due 2041 375,000 375,000 4.45% due 2042 400,000 400,000 Total notes 2,025,000 1,225,000 Total long-term debt issues 2,232,500 1,432,500 Unamortized debt issuance costs (16,408 ) (9,069 ) Unamortized debt premium and discount, net (5,338 ) (3,857 ) Total long-term debt $ 2,210,754 $ 1,419,574 Aggregate minimum maturities (face value) applicable to long-term debt outstanding at December 31, 2016 , for the next five years, are as follows (in thousands): 2018: 6.05% Notes $250,000 There are no maturities applicable to long-term debt outstanding for the years 2017, 2019, 2020 and 2021. No property is pledged as collateral under any of our long-term debt issues. Restrictive Debt Covenants At December 31, 2016 , none of our debt instruments restrict the amount of distributions to our parent, provided, however, that under the credit facility described below, we are restricted from making distributions to our parent during an event of default if we have directly incurred indebtedness under the credit facility. Our debt agreements contain restrictions on our ability to incur secured debt beyond certain levels and to guarantee certain indebtedness. The indenture governing our $1 billion of 7.85% Senior Notes due 2026 further restricts our ability to guarantee certain indebtedness. Issuance and Retirement of Long-Term Debt On January 22, 2016, we issued $1 billion of 7.85 percent senior unsecured notes due 2026 to investors in a private debt placement. A portion of these proceeds was used to retire our $200 million of 6.4 percent notes that matured on April 15, 2016. We used the remainder for funding of capital expenditures. As part of the new issuance, we entered into a registration rights agreement with the initial purchasers of the unsecured notes. We were obligated to file and consummate a registration statement for an offer to exchange the notes for a new issue of substantially identical notes registered under the Securities Act, within 365 days from closing and to use commercially reasonable efforts to complete the exchange offer. In January 2017, we completed an exchange of these notes for substantially identical new notes that are registered under the Securities Act. Credit Facility On February 2, 2015, we along with WPZ, Northwest, the lenders named therein and an administrative agent entered into the Second Amended and Restated Credit Agreement with aggregate commitments available of $3.5 billion, with up to an additional $500 million increase in aggregate commitments available under certain circumstances. The maturity date of the facility is February 2, 2020. However, the co-borrowers may request up to two extensions of the maturity date each for an additional one year period to allow a maturity date as late as February 2, 2022, under certain circumstances. The agreement allows for swing line loans up to aggregate amount of $150 million, subject to available capacity under the credit facility, and letters of credit commitments available to WPZ of $1.125 billion. We are able to borrow up to $500 million under this credit facility to the extent not otherwise utilized by the other co-borrowers. At December 31, 2016, no letters of credit have been issued and no loans to WPZ were outstanding under the credit facility. On December 18, 2015, we along with WPZ, Northwest, the lenders named therein and an administrative agent entered into the Amendment No. 1 to Second Amended & Restated Credit Agreement modifying the thresholds specified in the covenant related to the maximum ratio of WPZ's consolidated indebtedness to consolidated EBITDA. Under the credit facility, WPZ is required to maintain a ratio of debt to EBITDA (each as defined in the credit facility) that must be no greater than 5.75 to 1.0 for the quarters ending December 31, 2015, March 31, 2016 and June 30, 2016. The ratio must be no greater than 5.5 to 1.0 for the quarters ending September 30, 2016 and December 31, 2016. The ratio must be no greater than 5.0 to 1.0 for the quarter ending March 31, 2017 and each subsequent fiscal quarter, except for the fiscal quarter and the two following fiscal quarters in which one or more acquisitions has been executed, in which case the ratio must be no greater than 5.50 to 1.0. For us, the ratio of debt to capitalization (defined as net worth plus debt) must be no greater than 65 percent. Measured as of December 31, 2016 , we are in compliance with this financial covenant. Various covenants may limit, among other things, a borrower's and its material subsidiaries' ability to grant certain liens supporting indebtedness, a borrower's ability to merge or consolidate, sell all or substantially all of its assets, enter into certain affiliate transactions, make certain distributions during an event of default, enter into certain restrictive agreements, and allow any material change in the nature of its business. If an event of default with respect to a borrower occurs under the credit facility, the lenders will be able to terminate the commitments for the respective borrowers and accelerate the maturity of any loans of the defaulting borrower under the credit facility agreement and exercise other rights and remedies. Other than swingline loans, each time funds are borrowed, the borrower must choose whether such borrowing will be an alternate base rate borrowing or a Eurodollar borrowing. If such borrowing is an alternate base rate borrowing, interest is calculated on the basis of the greater of (a) the Prime Rate, (b) the Federal Funds Effective Rate plus 1/2 of 1 percent and (c) a periodic fixed rate equal to the London Interbank Offered Rate (LIBOR) plus 1 percent, plus, in the case of each of (a), (b) and (c), an applicable margin. If the borrowing is a Eurodollar borrowing, interest is calculated on the basis of LIBOR for the relevant period plus an applicable margin. Interest on swingline loans is calculated as the sum of the alternate base rate plus an applicable margin. The borrower is required to pay a commitment fee based on the unused portion of the credit facility. The applicable margin and the commitment fee are determined for each borrower by reference to a pricing schedule based on such borrower's senior unsecured long-term debt ratings. WPZ participates in a commercial paper program and WPZ management considers amounts outstanding under this program to be a reduction of available capacity under the credit facility. On February 2, 2015, WPZ amended and restated the commercial paper program for the WPZ/ACMP merger and to allow a maximum outstanding of $3 billion. At December 31, 2016, WPZ had $93 million in outstanding commercial paper. Lease Obligations The future minimum lease payments under our various operating leases are as follows (in thousands): 2017 $ 13,535 2018 13,539 2019 11,114 2020 11,085 2021 3,268 Thereafter 1,763 Total net minimum obligations $ 54,304 Our lease expense was $10.6 million in 2016 , $10.7 million in 2015 , and $11.1 million in 2014 . |
ARO Trust (Notes)
ARO Trust (Notes) | 12 Months Ended |
Dec. 31, 2016 | |
Investments, Debt and Equity Securities [Abstract] | |
ARO Trust | ARO TRUST Available-for-Sale Investments We are entitled to collect in rates the amounts necessary to fund our asset retirement obligations (ARO). We deposit monthly, into an external trust account (ARO Trust), the revenues specifically designated for ARO. The ARO Trust carries a moderate risk portfolio. We measure the financial instruments held in our ARO Trust at fair value. However, in accordance with the ASC Topic 980, Regulated Operations, both realized and unrealized gains and losses of the ARO Trust are recorded as regulatory assets or liabilities. Effective March 1, 2013, the annual funding obligation is approximately $36.4 million, with deposits made monthly. Investments in available-for-sale securities within the ARO Trust at fair value were as follows (in millions): December 31, 2016 December 31, 2015 Amortized Cost Basis Fair Value Amortized Cost Basis Fair Value Cash and Money Market Funds $ 5.0 $ 5.0 $ 3.2 $ 3.2 U.S. Equity Funds 29.4 36.5 19.2 22.9 International Equity Funds 19.2 18.6 16.1 15.0 Municipal Bond Funds 36.7 36.3 25.1 25.6 Total $ 90.3 $ 96.4 $ 63.6 $ 66.7 |
Fair Value Measurements (Notes)
Fair Value Measurements (Notes) | 12 Months Ended |
Dec. 31, 2016 | |
Fair Value Disclosures [Abstract] | |
Fair Value Measurements | FAIR VALUE MEASUREMENTS The following table presents, by level within the fair value hierarchy, certain of our financial assets and liabilities. The carrying values of cash, short-term financial assets (advances to affiliate) that have variable interest rates, accounts receivable and accounts payable approximate fair value because of the short-term nature of these instruments. Therefore, these assets and liabilities are not presented in the following table. Fair Value Measurements Using Carrying Amount Fair Value Quoted Prices In Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (Millions) Assets (liabilities) at December 31, 2016: Measured on a recurring basis: ARO Trust investments $ 96.4 $ 96.4 $ 96.4 $ — $ — Additional disclosures: Notes receivable — — — — — Long-term debt (2,210.8 ) (2,507.5 ) — (2,507.5 ) — Assets (liabilities) at December 31, 2015: Measured on a recurring basis: ARO Trust investments $ 66.7 $ 66.7 $ 66.7 $ — $ — Additional disclosures: Notes receivable 1.1 1.1 — 1.1 — Long-term debt (1,419.6 ) (1,244.1 ) — (1,244.1 ) — Fair Value of Methods The following methods and assumptions were used to estimate the fair value of each class of financial instruments for which it is practicable to estimate that value: ARO Trust investments - We deposit a portion of our collected rates, pursuant to the terms of the Docket No. RP12-993 rate case settlement, into the ARO Trust which is specifically designated to fund future asset retirement obligations. The ARO Trust invests in a portfolio of actively traded mutual funds that are measured at fair value on a recurring basis based on quoted prices in an active market, are classified as available-for-sale and are reported in Other Assets-Other in the Consolidated Balance Sheet. However, both realized and unrealized gains and losses are ultimately recorded as regulatory assets or liabilities. See Note 4 for more information regarding the ARO Trust. Notes receivable - The disclosed fair value of our notes receivable is determined by an income approach, which considers the underlying contract amounts and our assessment of our ability to recover these amounts. The balance in notes receivables is reported in Trade and other receivables in the Consolidated Balance Sheet. Long-term debt - The disclosed fair value of our long-term debt is determined by a market approach using broker quoted indicative period-end bond prices. The quoted prices are based on observable transactions in less active markets for our debt or similar instruments. Reclassifications of fair value between Level 1, Level 2, and Level 3 of the fair value hierarchy, if applicable, are made at the end of each quarter. No transfers between Level 1 and Level 2 occurred during the year ended December 31, 2016 or 2015 . |
Benefit Plans (Notes)
Benefit Plans (Notes) | 12 Months Ended |
Dec. 31, 2016 | |
Pension and Other Postretirement Benefit Expense [Abstract] | |
Benefit Plans | BENEFIT PLANS Certain of the benefit costs charged to us by Williams associated with employees who directly support us are described below. Additionally, allocated corporate expenses from Williams to us also include amounts related to these same employee benefits, which are not included in the amounts presented below. Pension and Other Postretirement Benefit Plans Williams has noncontributory defined benefit pension plans (Williams Pension Plan, Williams Inactive Employees Pension Plan and The Williams Companies Retirement Restoration Plan) that provide pension benefits for its eligible employees. Pension cost charged to us by Williams was $8.7 million, $13.5 million and $11.9 million for 2016 , 2015 , and 2014 , respectively. Williams makes annual cash contributions to the pension plans, based on annual actuarial estimates, which Transco recovers through rates that are set through periodic general rate filings. Effective with the RP12-993 Settlement, any amounts of annual contributions that exceed an upper threshold or fall below a lower threshold are recorded as adjustments to income and collected or refunded through future rate adjustments. The amount of deferred pension collections recorded as a regulatory liability at December 31, 2016 and 2015 were $21.3 million and $8.0 million, respectively. Williams provides subsidized retiree health care and life insurance benefits to certain eligible participants. Generally, participants that were employed by Williams on or before December 31, 1991 or December 31, 1995, if they were employees or retirees of Transco Energy Company and its subsidiaries, are eligible for subsidized retiree health care benefits. We recognized other postretirement benefit income of $12.0 million, $11.9 million, and $13.7 million for 2016, 2015, and 2014, respectively. We have been allowed by rate case settlements to collect or refund in future rates any differences between the actuarially determined costs and amounts currently being recovered in rates related to other postretirement benefits. Any differences between the annual actuarially determined cost and amounts currently being recovered in rates are recorded as an adjustment to expense and collected or refunded through future rate adjustments. The amount of other postretirement benefits costs deferred as a regulatory liability at December 31, 2016 and 2015 are $63.0 million and $51.0 million, respectively. These amounts are comprised of amounts being deferred for future rate treatment of $52.0 million and $37.4 million at December 31, 2016 and 2015, respectively, and amounts of $11.0 million and $13.6 million being amortized over a period of approximately 8 years per Docket No. RP12-993 at December 31, 2016 and 2015, respectively. Defined Contribution Plan Williams maintains a defined contribution plan for substantially all of its employees. Williams charged us compensation expense of $6.5 million in 2016, $6.6 million in 2015 and $6.4 million in 2014 for Williams’ company matching contributions to this plan. Employee Stock-Based Compensation Plan Information The Williams Companies, Inc. 2007 Incentive Plan, as subsequently amended and restated, (Plan) provides for Williams’ common stock based awards to both employees and non-management directors. The Plan permits the granting of various types of awards including, but not limited to, restricted stock units and stock options. Awards may be granted for no consideration other than prior and future services or based on certain financial performance targets achieved. Williams currently bills us directly for compensation expense related to stock-based compensation awards based on the fair value of the awards. We are also billed for our proportionate share of Williams’ and other affiliates’ stock-based compensation expense through various allocation processes. Total stock-based compensation expense for the years ended December 31, 2016 , 2015 , and 2014 was $4.0 million, $4.0 million and $3.0 million, respectively, excluding amounts allocated from WPZ and Williams. |
Transactions with Major Custome
Transactions with Major Customers and Affiliates (Notes) | 12 Months Ended |
Dec. 31, 2016 | |
Transactions with Major Customers and Affiliates [Abstract] | |
Transactions with Major Customers and Affiliates | TRANSACTIONS WITH MAJOR CUSTOMERS AND AFFILIATES Major Customers Operating revenues received from three of our major customers in 2016 , 2015 and 2014 are as follows (in millions): 2016 2015 2014 Duke Energy Corporation $ 178.9 $ 94.6 $ 91.5 National Grid 166.3 129.6 91.2 Public Service Enterprise Group 143.6 110.2 115.3 Affiliates We are a participant in WPZ’s cash management program, and we make advances to and receive advances from WPZ. At December 31, 2016 and 2015 , our advances to WPZ totaled approximately $811.7 million and $64.6 million , respectively. These advances are represented by demand notes and are classified as Current Assets in the accompanying Consolidated Balance Sheet. Advances are stated at the historical carrying amounts. Interest income is recognized when chargeable and collectability is reasonably assured. The interest rate on these intercompany demand notes is based upon the daily overnight investment rate paid on WPZ’s excess cash at the end of each month. At December 31, 2016 , the interest rate was 0.39 percent. Included in Operating Revenues in the accompanying Consolidated Statement of Comprehensive Income for 2016 , 2015 and 2014 are revenues received from affiliates of $11.2 million, $4.6 million, and $8.3 million, respectively. The rates charged to provide sales and services to affiliates are the same as those that are charged to similarly-situated nonaffiliated customers. Included in Cost of natural gas sales in the accompanying Consolidated Statement of Comprehensive Income for 2016 , 2015 and 2014 is purchased gas cost from affiliates of $4.3 million, $6.0 million, and $10.5 million, respectively. All gas purchases are made at market or contract prices. We have no employees. Services necessary to operate our business are provided to us by Williams and certain affiliates of Williams. We reimburse Williams and its affiliates for all direct and indirect expenses incurred or payments made (including salary, bonus, incentive compensation and benefits) in connection with these services. Employees of Williams also provide general, administrative and management services to us, and we are charged for certain administrative expenses incurred by Williams. These charges are either directly identifiable or allocated to our assets. Direct charges are for goods and services provided by Williams at our request. Allocated charges are based on a three-factor formula, which considers revenues; property, plant and equipment; and payroll. In management’s estimation, the allocation methodologies used are reasonable and result in a reasonable allocation to us of our costs of doing business incurred by Williams. We were billed $318.4 million, $327.1 million, and $310.1 million during 2016 , 2015 and 2014 , respectively, for these services. Such expenses are primarily included in Administrative and general and Operation and maintenance expenses in the accompanying Consolidated Statement of Comprehensive Income. The amount billed to us during 2016 includes $7.4 million for severance and other related costs associated with a reduction in workforce primarily recognized in the first quarter. We provide services to certain of our affiliates. We recorded reductions in operating expenses for services provided to and reimbursed by our affiliates of $4.3 million, $5.7 million, and $6.6 million in 2016 , 2015 and 2014 , respectively. Pursuant to construction agreements, we received pre-payments from WFS of $5.0 million during 2014 associated with capital projects. In 2015, we acquired certain assets from WFS for $1.9 million. We made equity distributions of $440 million , $536 million and $411 million during 2016 , 2015 and 2014 , respectively. In January 2017, an additional distribution of $100 million was declared and paid. During 2016 , 2015 and 2014 , our parent made contributions totaling $502 million , $652 million and $267 million , respectively, to us to fund a portion of our expenditures for additions to property, plant and equipment. In January 2017, our parent made an additional $110 million contribution to us. |
Asset Retirement Obligations (N
Asset Retirement Obligations (Notes) | 12 Months Ended |
Dec. 31, 2016 | |
Asset Retirement Obligation Disclosure [Abstract] | |
Asset Retirement Obligations | ASSET RETIREMENT OBLIGATIONS These accrued obligations relate to underground storage caverns, offshore platforms, pipelines, and gas transmission facilities. At the end of the useful life of each respective asset, we are legally obligated to plug storage caverns and remove any related surface equipment, to dismantle offshore platforms, to cap certain gathering pipelines at the wellhead connection and remove any related surface equipment, and to remove certain components of gas transmission facilities from the ground. During 2016 and 2015 , our overall asset retirement obligation changed as follows (in thousands): 2016 2015 Beginning balance $ 323,026 $ 296,475 Accretion 35,740 25,178 New obligations 7,995 256 Changes in estimates of existing obligations (1) (85,514 ) 3,691 Property dispositions/obligations settled (5,795 ) (2,574 ) Ending balance $ 275,452 $ 323,026 (1) Changes in estimates of existing obligations are primarily due to the annual review process, which considers various factors including inflation rate, current estimates for removal cost, discount rates, and the estimated remaining life of assets. The changes in estimates of existing obligations reflect a decrease of $86 million for 2016 and an increase of $4 million for 2015. The decrease in 2016 is due primarily to revisions in the estimated remaining life of assets and the current estimate to the inflation rate. The increase in 2015 is primarily due to current estimates for removal costs, inflation rate, and discount rates. We are entitled to collect in rates the amounts necessary to fund our ARO. All funds received for such retirements are deposited into an external trust account dedicated to funding our ARO. Under our current rate settlement our annual funding obligation is approximately $36.4 million, with installments to be deposited monthly (See Note 4). |
Regulatory Assets and Liabiliti
Regulatory Assets and Liabilities (Notes) | 12 Months Ended |
Dec. 31, 2016 | |
Regulatory Assets and Liabilities Disclosure [Abstract] | |
Regulatory Assets and Liabilities | REGULATORY ASSETS AND LIABILITIES The regulatory assets and regulatory liabilities resulting from our application of the provisions of ASC Topic 980, Regulated Operations, included in the accompanying Consolidated Balance Sheet at December 31, 2016 and December 31, 2015 are as follows (in millions): Regulatory Assets 2016 2015 Grossed-up deferred taxes on equity funds used during construction $ 73.2 $ 75.8 Asset retirement obligations 117.2 113.5 Asset retirement costs - Eminence 53.9 58.8 Deferred taxes 4.8 5.9 Deferred cash out 48.2 43.9 Fuel cost 51.3 43.8 Other 2.5 1.6 Total Regulatory Assets $ 351.1 $ 343.3 Regulatory Liabilities 2016 2015 Negative salvage $ 357.1 $ 318.3 Sentinel meter station depreciation 6.2 6.0 Postretirement benefits other than pension 63.0 51.0 Electric power cost 6.3 0.8 Pension - deferred collections 21.3 8.0 Deferred gas costs 4.5 1.6 Other 0.1 0.2 Total Regulatory Liabilities $ 458.5 $ 385.9 The significant regulatory assets and liabilities include: Grossed-up deferred taxes on equity funds used during construction : Regulatory asset balance established to offset the deferred tax for the equity component of the allowance for funds used during the construction of long-lived assets. All amounts were generated during the period that we were a taxable entity. Taxes on capitalized funds used during construction and the offsetting deferred income taxes are included in the rate base and are recovered over the depreciable lives of the long-lived asset to which they relate. Asset retirement obligations : Regulatory asset balance established to offset depreciation of the ARO asset and changes in the ARO liability due to the passage of time. The regulatory asset is being recovered through our rates, and is being amortized to expense consistent with the amounts collected in rates (See Note 8). Asset retirement costs - Eminence : Regulatory asset balance associated with the Eminence Storage Field retirement costs. The regulatory asset is being recovered through our rates, and is being amortized to expense consistent with the amounts collected in rates. Deferred taxes : Regulatory asset balance was established as a result of an increase to rate base deferred taxes due to an increase to the effective state income tax rate. The regulatory asset is being collected from rate payers over the remaining depreciable lives of the long-lived asset to which they relate. Deferred cash out : This amount represents the deferral of gains or losses on the purchases and sales of gas imbalances with shippers. These amounts are not included in the rate base but are expected to be recovered/refunded in subsequent annual cash out filing periods. Deferred gas costs : This amount arises from the movement of gas volumes between gas inventory accounts that have different valuations. These amounts are expected to be recovered/refunded in subsequent periods. Fuel cost : This amount represents the difference between the gas retained from our customers and the gas consumed in operations. These amounts are not included in the rate base but are expected to be recovered/refunded in subsequent annual fuel tracker filing periods. Negative salvage: Our rates include a component designed to recover certain future retirement costs for which we are not required to record an asset retirement obligation. We record a regulatory liability representing the cumulative residual amount of recoveries through rates, net of expenditures associated with these retirement costs. Sentinel meter station depreciation: This amount reflects the incremental depreciation being recorded related to the meter station modifications made for three of the Sentinel shippers. These modifications will be recovered through a surcharge over a defined period of time as stated in the Sentinel FERC order. The incremental depreciation represents the difference between the FERC granted depreciation rate for such facilities in the last rate case as compared to the depreciation rates in the Sentinel order which are based on the contractual terms in the surcharge agreements. The incremental depreciation will be recorded through the end of the contractual term and then will be amortized. Postretirement benefits: We recover the actuarially determined cost of postretirement benefits through rates that are set through periodic general rate filings. Any difference between the annual actuarially determined cost and the amount recovered in rates is recorded as a regulatory asset or liability to be collected or refunded through future rate adjustments. These amounts are not included in the rate base (See Note 6). Electric power cost : This amount represents the difference between the electric power costs recovered from our customers and the electric power costs incurred in operations. These amounts are not included in the rate base but are expected to be recovered/refunded in subsequent annual electric power tracker filing periods. Pension - deferred collections: We recover the actuarially determined pension cash contributions through rates that are set through periodic general rate filings. Effective with the RP12-993 Settlement, any amounts of annual contributions that exceed an upper threshold or fall below a lower threshold are recorded as adjustments to income and collected or refunded through future rate adjustments (See Note 6). |
Other (Notes)
Other (Notes) | 12 Months Ended |
Dec. 31, 2016 | |
Other Income and Expenses [Abstract] | |
Other | OTHER During 2016, we capitalized $1.4 million of project feasibility cost associated with one project, which had been expensed in prior periods in Other expense, net , upon determining that the project was probable of development. During 2014, we capitalized $3.5 million of project feasibility costs associated with various projects, which had been expensed in prior periods in Other expense, net , upon determining that the projects were probable of development. |
Summary of Significant Accoun18
Summary of Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2016 | |
Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
Regulatory Accounting | Regulatory Accounting We are regulated by the Federal Energy Regulatory Commission (FERC). The Accounting Standards Codification (ASC) Regulated Operations (Topic 980), provides that rate-regulated public utilities account for and report regulatory assets and liabilities consistent with the economic effect of the way in which regulators establish rates if the rates established are designed to recover the costs of providing the regulated service and if the competitive environment makes it probable that such rates can be charged and collected. Accounting for businesses that are regulated and apply the provisions of Topic 980 can differ from the accounting requirements for non-regulated businesses. Transactions that are recorded differently as a result of regulatory accounting requirements include the capitalization of an equity return component on regulated capital projects, capitalization of other project costs, retirements of general plant assets, employee related benefits, environmental costs, negative salvage, asset retirement obligations, and other costs and taxes included in, or expected to be included in, future rates. As a rate-regulated entity, our management has determined that it is appropriate to apply the accounting prescribed by Topic 980 and, accordingly, the accompanying consolidated financial statements include the effects of the types of transactions described above that result from regulatory accounting requirements. |
Basis of Presentation | Basis of Presentation Williams’ acquisition of Transco Energy Company and its subsidiaries, including us, in 1995 was accounted for using the purchase method of accounting. Accordingly, an allocation of the purchase price was assigned to our assets and liabilities based on their estimated fair values. The purchase price allocation to us primarily consisted of a $1.5 billion allocation to property, plant and equipment and adjustments to deferred taxes based upon the book basis of the net assets recorded as a result of the acquisition. The amount allocated to property, plant and equipment is being depreciated on a straight-line basis over 40 years, the estimated useful lives of these assets at the date of acquisition, at approximately $35 million per year. At December 31, 2016 , the remaining property, plant and equipment allocation was approximately $0.6 billion. Current FERC policy does not permit us to recover through rates amounts in excess of original cost. |
Principles of Consolidation | Principles of Consolidation The consolidated financial statements include our accounts and the accounts of the subsidiaries we control. Companies in which we and our subsidiaries own 20 percent to 50 percent of the voting common stock or otherwise exercise significant influence over operating and financial policies of the company are accounted for under the equity method. The equity method investments as of December 31, 2016 and December 31, 2015 consist of Cardinal Pipeline Company, LLC (Cardinal) with ownership interest of approximately 45 percent and Pine Needle LNG Company, LLC (Pine Needle) with ownership interest of 35 percent. We received distributions associated with our equity method investments totaling $8.6 million, $7.6 million, and $9.1 million in 2016 , 2015 and 2014 , respectively. Included in the distributions are $2.8 million, $2.0 million and $2.3 million return of capital in 2016, 2015 and 2014, respectively. |
Use of Estimates | Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. Estimates and assumptions which, in the opinion of management, are significant to the underlying amounts included in the financial statements and for which it would be reasonably possible that future events or information could change those estimates include: 1) revenues subject to refund; 2) litigation-related contingencies; 3) environmental remediation obligations; 4) impairment assessments of long-lived assets; 5) depreciation; and 6) asset retirement obligations. |
Revenue Recognition | Revenue Recognition Revenues for transportation of gas under long-term firm agreements are recognized considering separately the reservation and commodity charges. Reservation revenues are recognized monthly over the term of the agreement regardless of the volume of natural gas transported. Commodity revenues from both firm and interruptible transportation are recognized in the period transportation services are provided based on volumes of natural gas physically delivered at the agreed upon delivery point. Revenues for the storage of gas under firm agreements are recognized considering separately the reservation, capacity, and injection and withdrawal charges. Reservation and capacity revenues are recognized monthly over the term of the agreement regardless of the volume of storage service actually utilized. Injection and withdrawal revenues are recognized in the period when volumes of natural gas are physically injected into or withdrawn from storage. In the course of providing transportation services to customers, we may receive different quantities of gas from shippers than the quantities delivered on behalf of those shippers. The resulting imbalances are primarily settled through the purchase and sale of gas with our customers under terms provided in our FERC tariff. Revenue is recognized from the sale of gas upon settlement of the transportation and exchange imbalances (See Gas Imbalances in this Note). As a result of the ratemaking process, certain revenues collected by us may be subject to refunds upon the issuance of final orders by the FERC in pending rate proceedings. We record estimates of rate refund liabilities considering our and other third-party regulatory proceedings, advice of counsel and other risks. |
Environmental Matters | Environmental Matters We are subject to federal, state, and local environmental laws and regulations. Environmental expenditures are expensed or capitalized depending on their economic benefit and potential for rate recovery. We believe that any expenditures required to meet applicable environmental laws and regulations are prudently incurred in the ordinary course of business and such expenditures would be permitted to be recovered through rates. |
Property, Plant and Equipment | Property, Plant and Equipment Property, plant and equipment is recorded at cost. The carrying values of these assets are also based on estimates, assumptions and judgments relative to capitalized costs, useful lives and salvage values. These estimates, assumptions and judgments reflect FERC regulations, as well as historical experience and expectations regarding future industry conditions and operations. The FERC identifies installation, construction and replacement costs that are to be capitalized. All other costs are expensed as incurred. Gains or losses from the ordinary sale or retirement of property, plant and equipment are credited or charged to accumulated depreciation; certain other gains or losses are recorded in operating income. We provide for depreciation under the composite (group) method at straight-line FERC prescribed rates that are applied to the cost of the group for transmission facilities, production and gathering facilities and storage facilities. Under this method, assets with similar lives and characteristics are grouped and depreciated as one asset. Included in our depreciation rates is a negative salvage component (net cost of removal) that we currently collect in rates. Our depreciation rates are subject to change each time we file a general rate case with the FERC. Depreciation rates used for major regulated gas plant facilities at December 31, 2016 , 2015 and 2014 are as follows: Category of Property 2016-2014 Gathering facilities 1.35% - 2.50% Storage facilities 2.10% - 2.25% Onshore transmission facilities 2.61% - 5.00% Offshore transmission facilities 1.20% - 1.20% We record a liability and increase the basis in the underlying asset for the present value of each expected future asset retirement obligation (ARO) at the time the liability is initially incurred, typically when the asset is acquired or constructed. Measurements of AROs include, as a component of future expected costs, an estimate of the price that a third party would demand, and could expect to receive, for bearing the uncertainties inherent in the obligations, sometimes referred to as a market-risk premium. The ARO asset is depreciated in a manner consistent with the expected timing of the future abandonment of the underlying physical assets. We measure changes in the liability due to passage of time by applying an interest method of allocation. The depreciation of the ARO asset and accretion of the ARO liability are recognized as an increase to a regulatory asset, as management expects to recover such amounts in future rates. The regulatory asset is amortized commensurate with our collection of these costs in rates. |
Impairment of Long-Lived Assets | Impairment of Long-lived Assets We evaluate the long lived assets of identifiable business activities for impairment when events or changes in circumstances indicate, in our management’s judgment, that the carrying value of such assets may not be recoverable. When an indicator of a potential impairment has occurred we compare our management’s estimate of undiscounted future cash flows attributable to the assets to the carrying value of the assets to determine whether an impairment has occurred. We apply a probability-weighted approach to consider the likelihood of different cash flow assumptions and possible outcomes including selling in the near term or holding for the remaining estimated useful life. If an impairment of the carrying value has occurred, we determine the amount of the impairment recognized in the financial statements by estimating the fair value of the assets and recording a loss for the amount that the carrying value exceeds the estimated fair value. For assets identified to be disposed of in the future and considered held for sale in accordance with the ASC Property, Plant, and Equipment (Topic 360), we compare the carrying value to the estimated fair value less the cost to sell to determine if recognition of an impairment is required. Until the assets are disposed of, the estimated fair value, which includes estimated cash flows from operations until the assumed date of sale, is recalculated when related events or circumstances change. Judgments and assumptions are inherent in our management’s estimate of undiscounted future cash flows used to determine recoverability of an asset and the estimate of an asset’s fair value used to calculate the amount of impairment to recognize. |
Allowance for Funds Used During Construction | Allowance for Funds Used During Construction Allowance for funds used during construction (AFUDC) represents the estimated cost of borrowed and equity funds applicable to utility plant in process of construction and are included as a cost of property, plant and equipment because it constitutes an actual cost of construction under established regulatory practices. The FERC has prescribed a formula to be used in computing separate allowances for borrowed and equity AFUDC. The allowance for borrowed funds used during construction was $12.5 million, $14.6 million and $6.3 million, for 2016 , 2015 and 2014 , respectively. The allowance for equity funds was $56.5 million, $48.4 million, and $18.7 million, for 2016 , 2015 and 2014 , respectively. |
Income Taxes | Income Taxes We generally are not a taxable entity for federal or state and local income tax purposes. The tax on net income is generally borne by unitholders of our ultimate parent, WPZ. Net income for financial statement purposes may differ significantly from taxable income of WPZ’s unitholders as a result of differences between the tax basis and financial reporting basis of assets and liabilities and the taxable income allocation requirements under the WPZ partnership agreement. The aggregated difference in the basis of our assets for financial and tax reporting purposes cannot be readily determined because information regarding each of WPZ’s unitholder’s tax attributes in WPZ is not available to us. |
Accounts Receivable and Allowance for Doubtful Receivables | Accounts Receivable and Allowance for Doubtful Receivables Accounts receivable are stated at the historical carrying amount net of reserves or write-offs. Our credit risk exposure in the event of nonperformance by the other parties is limited to the face value of the receivables. We perform ongoing credit evaluations of our customers’ financial condition and require collateral from our customers, if necessary. Due to our customer base, we have not historically experienced recurring credit losses in connection with our receivables. Receivables determined to be uncollectible are reserved or written off in the period of determination. |
Gas Imbalances | Gas Imbalances In the course of providing transportation services to customers, we may receive different quantities of gas from shippers than the quantities delivered on behalf of those shippers. Additionally, we transport gas on various pipeline systems which may deliver different quantities of gas on behalf of us than the quantities of gas received from us. These transactions result in gas transportation and exchange imbalance receivables and payables which are recovered or repaid in cash or through the receipt or delivery of gas in the future and are recorded in the accompanying Consolidated Balance Sheet. Settlement of imbalances requires agreement between the pipelines and shippers as to allocations of volumes to specific transportation contracts and timing of delivery of gas based on operational conditions. Our tariff includes a method whereby most transportation imbalances are settled on a monthly basis. Each month a portion of the imbalances are not identified to specific parties and remain unsettled. These are generally identified to specific parties and settled in subsequent periods. We believe that amounts that remain unidentified to specific parties and unsettled at year end are valid balances that will be settled with no material adverse effect upon our financial position, results of operations or cash flows. Management has implemented a policy of continuing to carry any unidentified transportation and exchange imbalances on the books for a three-year period. At the end of the three year period a final assessment will be made of their continued validity. Absent a valid reason for maintaining the imbalance, any remaining balance will be recognized in income. Certain imbalances are being recovered or repaid in cash or through the receipt or delivery of gas upon agreement of the parties as to the allocation of the gas volumes, and as permitted by pipeline operating conditions. These imbalances have been classified as current assets and current liabilities at December 31, 2016 and 2015. We utilize the average cost method of accounting for gas imbalances. Deferred Cash Out Most transportation imbalances are settled in cash on a monthly basis (cash out). We are required by our tariff to refund revenues received from the cash out of transportation imbalances in excess of costs incurred during the annual August through July reporting period. Revenues received in excess of costs incurred are deferred until refunded in accordance with the tariff. |
Inventory | Gas Inventory We utilize the last-in, first-out (LIFO) method of accounting for inventory gas in storage. At December 31, 2016 and 2015, Gas in Storage, at LIFO, was zero. The basis for determining current cost at the end of each year is the December monthly average gas price delivered to pipelines in Texas and Louisiana. We utilize the average cost method of accounting for gas available for customer nomination. Liquefied natural gas in storage is valued at original cost. Materials and Supplies Inventory All inventories are stated at lower of average cost or market. We perform an annual review of Materials and Supplies inventories, including a quarterly analysis of parts that may no longer be useful due to planned replacements of compressor engines and other components on our system. Based on this assessment, we record a reserve for the value of the inventory which can no longer be used for maintenance and repairs on our pipeline. There was a minimal reserve at December 31, 2016 and 2015. |
Contingent Liabilities | Contingent Liabilities We record liabilities for estimated loss contingencies, including environmental matters, when we assess that a loss is probable and the amount of the loss can be reasonably estimated. These liabilities are calculated based upon our assumptions and estimates with respect to the likelihood or amount of loss and upon advice of legal counsel, engineers, or other third parties regarding the probable outcomes of the matters. These calculations are made without consideration of any potential recovery from third-parties. We recognize insurance recoveries or reimbursements from others when realizable. Revisions to these liabilities are generally reflected in income when new or different facts or information become known or circumstances change that affect the previous assumptions or estimates. |
Pension and Other Postretirement Benefits | Pension and Other Postretirement Benefits We do not have employees. Certain of the costs charged to us by Williams associated with employees who directly support us include costs related to Williams’ pension and other postretirement benefit plans. (See Note 6.) Although the underlying benefit plans of Williams are single-employer plans, we follow multiemployer plan accounting whereby the amount charged to us and thus paid by us, is based on our share of net periodic benefit cost. |
Cash Equivalents | We include short-term, highly-liquid investments that have an original maturity of three months or less as cash equivalents. |
Fair Value Measurements (Polici
Fair Value Measurements (Policies) | 12 Months Ended |
Dec. 31, 2016 | |
Fair Value Disclosures [Abstract] | |
Fair Value Measurements | Fair Value of Methods The following methods and assumptions were used to estimate the fair value of each class of financial instruments for which it is practicable to estimate that value: ARO Trust investments - We deposit a portion of our collected rates, pursuant to the terms of the Docket No. RP12-993 rate case settlement, into the ARO Trust which is specifically designated to fund future asset retirement obligations. The ARO Trust invests in a portfolio of actively traded mutual funds that are measured at fair value on a recurring basis based on quoted prices in an active market, are classified as available-for-sale and are reported in Other Assets-Other in the Consolidated Balance Sheet. However, both realized and unrealized gains and losses are ultimately recorded as regulatory assets or liabilities. See Note 4 for more information regarding the ARO Trust. Notes receivable - The disclosed fair value of our notes receivable is determined by an income approach, which considers the underlying contract amounts and our assessment of our ability to recover these amounts. The balance in notes receivables is reported in Trade and other receivables in the Consolidated Balance Sheet. Long-term debt - The disclosed fair value of our long-term debt is determined by a market approach using broker quoted indicative period-end bond prices. The quoted prices are based on observable transactions in less active markets for our debt or similar instruments. Reclassifications of fair value between Level 1, Level 2, and Level 3 of the fair value hierarchy, if applicable, are made at the end of each quarter. No transfers between Level 1 and Level 2 occurred during the year ended December 31, 2016 or 2015 . |
Summary of Significant Accoun20
Summary of Significant Accounting Policies (Tables) | 12 Months Ended |
Dec. 31, 2016 | |
Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
Depreciation rates | We provide for depreciation under the composite (group) method at straight-line FERC prescribed rates that are applied to the cost of the group for transmission facilities, production and gathering facilities and storage facilities. Under this method, assets with similar lives and characteristics are grouped and depreciated as one asset. Included in our depreciation rates is a negative salvage component (net cost of removal) that we currently collect in rates. Our depreciation rates are subject to change each time we file a general rate case with the FERC. Depreciation rates used for major regulated gas plant facilities at December 31, 2016 , 2015 and 2014 are as follows: Category of Property 2016-2014 Gathering facilities 1.35% - 2.50% Storage facilities 2.10% - 2.25% Onshore transmission facilities 2.61% - 5.00% Offshore transmission facilities 1.20% - 1.20% |
Debt, Financing Arrangements 21
Debt, Financing Arrangements and Leases (Tables) | 12 Months Ended |
Dec. 31, 2016 | |
Debt Disclosure [Abstract] | |
Long-term debt | At December 31, 2016 and 2015 , long-term debt issues were outstanding as follows (in thousands): 2016 2015 Debentures: 7.08% due 2026 $ 7,500 $ 7,500 7.25% due 2026 200,000 200,000 Total debentures 207,500 207,500 Notes: 6.4% due 2016 — 200,000 6.05% due 2018 250,000 250,000 7.85% due 2026 1,000,000 — 5.4% due 2041 375,000 375,000 4.45% due 2042 400,000 400,000 Total notes 2,025,000 1,225,000 Total long-term debt issues 2,232,500 1,432,500 Unamortized debt issuance costs (16,408 ) (9,069 ) Unamortized debt premium and discount, net (5,338 ) (3,857 ) Total long-term debt $ 2,210,754 $ 1,419,574 |
Maturities of long-term debt | Aggregate minimum maturities (face value) applicable to long-term debt outstanding at December 31, 2016 , for the next five years, are as follows (in thousands): 2018: 6.05% Notes $250,000 |
Future minimum lease payments | The future minimum lease payments under our various operating leases are as follows (in thousands): 2017 $ 13,535 2018 13,539 2019 11,114 2020 11,085 2021 3,268 Thereafter 1,763 Total net minimum obligations $ 54,304 |
ARO Trust (Tables)
ARO Trust (Tables) | 12 Months Ended |
Dec. 31, 2016 | |
Investments, Debt and Equity Securities [Abstract] | |
ARO Trust | Investments in available-for-sale securities within the ARO Trust at fair value were as follows (in millions): December 31, 2016 December 31, 2015 Amortized Cost Basis Fair Value Amortized Cost Basis Fair Value Cash and Money Market Funds $ 5.0 $ 5.0 $ 3.2 $ 3.2 U.S. Equity Funds 29.4 36.5 19.2 22.9 International Equity Funds 19.2 18.6 16.1 15.0 Municipal Bond Funds 36.7 36.3 25.1 25.6 Total $ 90.3 $ 96.4 $ 63.6 $ 66.7 |
Fair Value Measurements (Tables
Fair Value Measurements (Tables) | 12 Months Ended |
Dec. 31, 2016 | |
Fair Value Disclosures [Abstract] | |
Schedule of fair value, assets and liabilities measured on recurring basis | The following table presents, by level within the fair value hierarchy, certain of our financial assets and liabilities. The carrying values of cash, short-term financial assets (advances to affiliate) that have variable interest rates, accounts receivable and accounts payable approximate fair value because of the short-term nature of these instruments. Therefore, these assets and liabilities are not presented in the following table. Fair Value Measurements Using Carrying Amount Fair Value Quoted Prices In Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (Millions) Assets (liabilities) at December 31, 2016: Measured on a recurring basis: ARO Trust investments $ 96.4 $ 96.4 $ 96.4 $ — $ — Additional disclosures: Notes receivable — — — — — Long-term debt (2,210.8 ) (2,507.5 ) — (2,507.5 ) — Assets (liabilities) at December 31, 2015: Measured on a recurring basis: ARO Trust investments $ 66.7 $ 66.7 $ 66.7 $ — $ — Additional disclosures: Notes receivable 1.1 1.1 — 1.1 — Long-term debt (1,419.6 ) (1,244.1 ) — (1,244.1 ) — |
Transactions with Major Custo24
Transactions with Major Customers and Affiliates (Tables) | 12 Months Ended |
Dec. 31, 2016 | |
Transactions with Major Customers and Affiliates [Abstract] | |
Schedule of revenue by major customers | Operating revenues received from three of our major customers in 2016 , 2015 and 2014 are as follows (in millions): 2016 2015 2014 Duke Energy Corporation $ 178.9 $ 94.6 $ 91.5 National Grid 166.3 129.6 91.2 Public Service Enterprise Group 143.6 110.2 115.3 |
Asset Retirement Obligations (T
Asset Retirement Obligations (Tables) | 12 Months Ended |
Dec. 31, 2016 | |
Asset Retirement Obligation Disclosure [Abstract] | |
Schedule of change in asset retirement obligation | During 2016 and 2015 , our overall asset retirement obligation changed as follows (in thousands): 2016 2015 Beginning balance $ 323,026 $ 296,475 Accretion 35,740 25,178 New obligations 7,995 256 Changes in estimates of existing obligations (1) (85,514 ) 3,691 Property dispositions/obligations settled (5,795 ) (2,574 ) Ending balance $ 275,452 $ 323,026 (1) Changes in estimates of existing obligations are primarily due to the annual review process, which considers various factors including inflation rate, current estimates for removal cost, discount rates, and the estimated remaining life of assets. The changes in estimates of existing obligations reflect a decrease of $86 million for 2016 and an increase of $4 million for 2015. The decrease in 2016 is due primarily to revisions in the estimated remaining life of assets and the current estimate to the inflation rate. The increase in 2015 is primarily due to current estimates for removal costs, inflation rate, and discount rates. |
Regulatory Assets and Liabili26
Regulatory Assets and Liabilities (Tables) | 12 Months Ended |
Dec. 31, 2016 | |
Regulatory Assets and Liabilities Disclosure [Abstract] | |
Schedule of Regulatory Assets [Table Text Block] | The regulatory assets and regulatory liabilities resulting from our application of the provisions of ASC Topic 980, Regulated Operations, included in the accompanying Consolidated Balance Sheet at December 31, 2016 and December 31, 2015 are as follows (in millions): Regulatory Assets 2016 2015 Grossed-up deferred taxes on equity funds used during construction $ 73.2 $ 75.8 Asset retirement obligations 117.2 113.5 Asset retirement costs - Eminence 53.9 58.8 Deferred taxes 4.8 5.9 Deferred cash out 48.2 43.9 Fuel cost 51.3 43.8 Other 2.5 1.6 Total Regulatory Assets $ 351.1 $ 343.3 |
Schedule of Regulatory Liabilities [Table Text Block] | Regulatory Liabilities 2016 2015 Negative salvage $ 357.1 $ 318.3 Sentinel meter station depreciation 6.2 6.0 Postretirement benefits other than pension 63.0 51.0 Electric power cost 6.3 0.8 Pension - deferred collections 21.3 8.0 Deferred gas costs 4.5 1.6 Other 0.1 0.2 Total Regulatory Liabilities $ 458.5 $ 385.9 |
Summary of Significant Accoun27
Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands | 1 Months Ended | 12 Months Ended | ||
Jan. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | |
Subsidiary of Limited Liability Company or Limited Partnership [Line Items] | ||||
Parent, total ownership percentage | 60.00% | |||
Parent, limited partner ownership percentage | 58.00% | |||
Parent, general partner ownership percentage | 2.00% | |||
Purchase Price Allocation | ||||
Purchase price allocation, gross | $ 1,500,000 | |||
Purchase price allocation, property, plant and equipment, estimated useful lIfe | 40 years | |||
Purchase price allocation, depreciation | $ 35,000 | |||
Purchase price allocation, remaining allocation | 600,000 | |||
Schedule of Equity Method Investments [Line Items] | ||||
Equity method investment, distributions | 8,600 | $ 7,600 | $ 9,100 | |
Equity method investment, return of capital | 2,767 | 2,015 | 2,333 | |
Capitalized Interest Costs, Including Allowance for Funds Used During Construction [Abstract] | ||||
Allowance for funds used during construction, borrowed | 12,500 | 14,600 | 6,300 | |
Allowance for funds used during construction, equity | 56,468 | 48,435 | $ 18,701 | |
Inventory Disclosure [Abstract] | ||||
Gas in storage, LIFO | 0 | 0 | ||
Excess of replacement cost over LIFO cost | $ 0 | $ 0 | ||
Subsequent Event [Member] | Financial Repositioning [Member] | ||||
Subsidiary of Limited Liability Company or Limited Partnership [Line Items] | ||||
Parent, limited partner ownership percentage | 74.00% | |||
Parent, general partner ownership percentage | 2.00% | |||
Gathering facilities | Minimum | ||||
Public Utility, Property, Plant and Equipment [Line Items] | ||||
Depreciation rates | 1.35% | 1.35% | 1.35% | |
Gathering facilities | Maximum | ||||
Public Utility, Property, Plant and Equipment [Line Items] | ||||
Depreciation rates | 2.50% | 2.50% | 2.50% | |
Storage facilities | Minimum | ||||
Public Utility, Property, Plant and Equipment [Line Items] | ||||
Depreciation rates | 2.10% | 2.10% | 2.10% | |
Storage facilities | Maximum | ||||
Public Utility, Property, Plant and Equipment [Line Items] | ||||
Depreciation rates | 2.25% | 2.25% | 2.25% | |
Onshore transmission facilities | Minimum | ||||
Public Utility, Property, Plant and Equipment [Line Items] | ||||
Depreciation rates | 2.61% | 2.61% | 2.61% | |
Onshore transmission facilities | Maximum | ||||
Public Utility, Property, Plant and Equipment [Line Items] | ||||
Depreciation rates | 5.00% | 5.00% | 5.00% | |
Offshore transmission facilities | Minimum | ||||
Public Utility, Property, Plant and Equipment [Line Items] | ||||
Depreciation rates | 1.20% | 1.20% | 1.20% | |
Offshore transmission facilities | Maximum | ||||
Public Utility, Property, Plant and Equipment [Line Items] | ||||
Depreciation rates | 1.20% | 1.20% | 1.20% | |
Cardinal Pipeline Company, LLC | ||||
Schedule of Equity Method Investments [Line Items] | ||||
Equity method investment, ownership percentage | 45.00% | 45.00% | ||
Pine Needle LNG Company, LLC | ||||
Schedule of Equity Method Investments [Line Items] | ||||
Equity method investment, ownership percentage | 35.00% | 35.00% |
Contingent Liabilities and Co28
Contingent Liabilities and Commitments (Details) - USD ($) | 12 Months Ended | |
Dec. 31, 2016 | Dec. 31, 2015 | |
Site Contingency [Line Items] | ||
Regulatory assets, total | $ 351,100,000 | $ 343,300,000 |
Regulatory assets, current | 87,059,000 | 79,575,000 |
Regulatory assets, noncurrent | 264,001,000 | 263,730,000 |
Other Commitments [Abstract] | ||
Commitments for construction and acquisition of property, plant, and equipment | 84,000,000 | |
Environmental assessment and remediation | ||
Site Contingency [Line Items] | ||
Accrued environmental assessment and remediation costs, total | 4,200,000 | 2,900,000 |
Accrued environmental assessment and remediation costs, current | 2,100,000 | 1,400,000 |
Accrued environmental assessment and remediation costs, noncurrent | 2,100,000 | 1,500,000 |
Regulatory assets, total | 2,500,000 | 1,600,000 |
Regulatory assets, current | 1,200,000 | 1,200,000 |
Regulatory assets, noncurrent | 1,300,000 | $ 400,000 |
Environmental assessment and remediation | Minimum | ||
Site Contingency [Line Items] | ||
Environmental assessment and remediation costs, best estimate | $ 6,000,000 | |
Expected duration of environmental assessment and remediation spending | 4 years | |
Environmental assessment and remediation | Maximum | ||
Site Contingency [Line Items] | ||
Environmental assessment and remediation costs, best estimate | $ 8,000,000 | |
Expected duration of environmental assessment and remediation spending | 6 years | |
Potentially responsible party at various Superfund and state waste disposal sites | Maximum | ||
Site Contingency [Line Items] | ||
Environmental assessment and remediation costs, best estimate | $ 500,000 | |
Revenue | ||
Site Contingency [Line Items] | ||
Potential refund obligation | 15,300,000 | |
Interest Expense | ||
Site Contingency [Line Items] | ||
Potential refund obligation | 3,400,000 | |
Accrued Liabilities | ||
Site Contingency [Line Items] | ||
Potential refund obligation | 18,700,000 | |
Notice of Penalty | $ 1,600 |
Debt, Financing Arrangements 29
Debt, Financing Arrangements and Leases (Details) | Apr. 15, 2016USD ($) | Dec. 18, 2015 | Feb. 02, 2015USD ($) | Dec. 31, 2016USD ($) | Dec. 31, 2015USD ($) | Dec. 31, 2014USD ($) | Jan. 22, 2016USD ($) |
Debt Instrument [Line Items] | |||||||
Total long-term debt issues | $ 2,232,500,000 | $ 1,432,500,000 | |||||
Unamortized debt issuance costs | (16,408,000) | (9,069,000) | |||||
Unamortized debt premium and discount, net | (5,338,000) | (3,857,000) | |||||
Total long-term debt | 2,210,754,000 | 1,419,574,000 | |||||
Maturities of Long-term Debt [Abstract] | |||||||
2018: 6.05% Notes | 250,000,000 | ||||||
Long-term Debt, Fiscal Year Maturity [Abstract] | |||||||
2,017 | 0 | ||||||
2,019 | 0 | ||||||
2,020 | 0 | ||||||
2,021 | 0 | ||||||
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] | |||||||
2,017 | 13,535,000 | ||||||
2,018 | 13,539,000 | ||||||
2,019 | 11,114,000 | ||||||
2,020 | 11,085,000 | ||||||
2,021 | 3,268,000 | ||||||
Thereafter | 1,763,000 | ||||||
Total net minimum obligations | 54,304,000 | ||||||
Operating leases, rent expense | 10,600,000 | 10,700,000 | $ 11,100,000 | ||||
Williams Partners L.P. [Member] | |||||||
Line of Credit Facility [Line Items] | |||||||
Line of credit facility, maximum borrowing capacity | $ 3,500,000,000 | ||||||
Additional amount by which credit facility can be increased | 500,000,000 | ||||||
Line of Credit Facility, Remaining Borrowing Capacity | $ 500,000,000 | ||||||
Debt to EBITDA, after acquisitions, ratio | 5.50 | ||||||
Maximum Ratio Of Debt To Capitalization | 65.00% | ||||||
Commercial paper | 93,000,000 | ||||||
Williams Partners L.P. [Member] | Dec 2015, Mar & Jun 2016 [Member] | |||||||
Line of Credit Facility [Line Items] | |||||||
Maximum Ratio Of Debt To EBITDA | 5.75 | ||||||
Williams Partners L.P. [Member] | Sep & Dec 2016 [Member] | |||||||
Line of Credit Facility [Line Items] | |||||||
Maximum Ratio Of Debt To EBITDA | 5.5 | ||||||
Williams Partners L.P. [Member] | Mar 2017 & Subsequent Quarters [Member] | |||||||
Line of Credit Facility [Line Items] | |||||||
Maximum Ratio Of Debt To EBITDA | 5 | ||||||
Williams Partners L.P. [Member] | Rate addition to federal funds effective rate [Member] | |||||||
Line of Credit Facility [Line Items] | |||||||
Line of credit facility, basis spread on variable rate | 0.50% | ||||||
Williams Partners L.P. [Member] | Rate addition to London interbank offered rate (LIBOR) [Member] | |||||||
Line of Credit Facility [Line Items] | |||||||
Line of credit facility, basis spread on variable rate | 1.00% | ||||||
6.4% due 2016 [Member] | |||||||
Debt Instrument [Line Items] | |||||||
Long-term debt interest rate | 6.40% | ||||||
Long-Term Debt, retired | $ 200,000,000 | ||||||
7.85% due 2026 | |||||||
Debt Instrument [Line Items] | |||||||
Long-term debt interest rate | 7.85% | ||||||
Debentures | |||||||
Debt Instrument [Line Items] | |||||||
Total long-term debt issues | 207,500,000 | 207,500,000 | |||||
Debentures | 7.08% due 2026 [Member] | |||||||
Debt Instrument [Line Items] | |||||||
Total long-term debt issues | 7,500,000 | 7,500,000 | |||||
Debentures | 7.25% due 2026 [Member] | |||||||
Debt Instrument [Line Items] | |||||||
Total long-term debt issues | 200,000,000 | 200,000,000 | |||||
Notes | |||||||
Debt Instrument [Line Items] | |||||||
Total long-term debt issues | 2,025,000,000 | 1,225,000,000 | |||||
Notes | 6.4% due 2016 [Member] | |||||||
Debt Instrument [Line Items] | |||||||
Total long-term debt issues | 0 | 200,000,000 | |||||
Notes | 6.05% due 2018 [Member] | |||||||
Debt Instrument [Line Items] | |||||||
Total long-term debt issues | 250,000,000 | 250,000,000 | |||||
Notes | 7.85% due 2026 | |||||||
Debt Instrument [Line Items] | |||||||
Total long-term debt issues | 1,000,000,000 | 0 | |||||
Long-term debt face amount | $ 1,000,000,000 | ||||||
Notes | 5.4% due 2041 [Member] | |||||||
Debt Instrument [Line Items] | |||||||
Total long-term debt issues | 375,000,000 | 375,000,000 | |||||
Notes | 4.45% due 2042 [Member] | |||||||
Debt Instrument [Line Items] | |||||||
Total long-term debt issues | 400,000,000 | $ 400,000,000 | |||||
$3.5 billion credit facility [Member] | Williams Partners L.P. [Member] | |||||||
Line of Credit Facility [Line Items] | |||||||
Letters of credit outstanding, amount | 0 | ||||||
Line of credit facility, amount outstanding | $ 0 | ||||||
Swing Line Advances [Member] | Williams Partners L.P. [Member] | |||||||
Line of Credit Facility [Line Items] | |||||||
Line of credit facility, maximum borrowing capacity | $ 150,000,000 | ||||||
Commercial paper [Member] | Williams Partners L.P. [Member] | |||||||
Line of Credit Facility [Line Items] | |||||||
Line of credit facility, maximum borrowing capacity | 3,000,000,000 | ||||||
Letter of Credit [Member] | Williams Partners L.P. [Member] | |||||||
Line of Credit Facility [Line Items] | |||||||
Line of credit facility, maximum borrowing capacity | $ 1,125,000,000 |
ARO Trust (Details)
ARO Trust (Details) - USD ($) $ in Millions | Dec. 31, 2016 | Dec. 31, 2015 |
Investments, Debt and Equity Securities [Abstract] | ||
Annual funding obligation | $ 36.4 | |
Schedule of Available-for-sale Securities [Line Items] | ||
Available-for-sale securities, amortized cost basis | 90.3 | $ 63.6 |
Available-for-sale securities, fair value | 96.4 | 66.7 |
Cash And Money Market Funds [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Available-for-sale securities, amortized cost basis | 5 | 3.2 |
Available-for-sale securities, fair value | 5 | 3.2 |
U.S. Equity Funds [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Available-for-sale securities, amortized cost basis | 29.4 | 19.2 |
Available-for-sale securities, fair value | 36.5 | 22.9 |
International Equity Funds [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Available-for-sale securities, amortized cost basis | 19.2 | 16.1 |
Available-for-sale securities, fair value | 18.6 | 15 |
Municipal Bond Funds [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Available-for-sale securities, amortized cost basis | 36.7 | 25.1 |
Available-for-sale securities, fair value | $ 36.3 | $ 25.6 |
Fair Value Measurements (Detail
Fair Value Measurements (Details) - USD ($) | Dec. 31, 2016 | Dec. 31, 2015 |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] | ||
ARO Trust investments | $ 96,400,000 | $ 66,700,000 |
Fair Value, Transfers Between Level 1 and Level 2, Description and Policy [Abstract] | ||
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount | 0 | 0 |
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount | 0 | 0 |
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount | 0 | 0 |
Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | ||
Additional Fair Value Elements [Abstract] | ||
Notes Receivable, Fair Value Disclosure | 0 | 0 |
Long-term Debt, Fair Value | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | ||
Additional Fair Value Elements [Abstract] | ||
Notes Receivable, Fair Value Disclosure | 0 | 1,100,000 |
Long-term Debt, Fair Value | (2,507,500,000) | (1,244,100,000) |
Fair Value, Inputs, Level 3 [Member] | ||
Additional Fair Value Elements [Abstract] | ||
Notes Receivable, Fair Value Disclosure | 0 | 0 |
Long-term Debt, Fair Value | 0 | 0 |
Reported Value Measurement [Member] | ||
Additional Fair Value Elements [Abstract] | ||
Notes Receivable, Fair Value Disclosure | 0 | 1,100,000 |
Long-term Debt, Fair Value | (2,210,800,000) | (1,419,600,000) |
Estimate of Fair Value Measurement [Member] | ||
Additional Fair Value Elements [Abstract] | ||
Notes Receivable, Fair Value Disclosure | 0 | 1,100,000 |
Long-term Debt, Fair Value | (2,507,500,000) | (1,244,100,000) |
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | ||
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] | ||
ARO Trust investments | 96,400,000 | 66,700,000 |
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | ||
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] | ||
ARO Trust investments | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | ||
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] | ||
ARO Trust investments | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Reported Value Measurement [Member] | ||
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] | ||
ARO Trust investments | 96,400,000 | 66,700,000 |
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | ||
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] | ||
ARO Trust investments | $ 96,400,000 | $ 66,700,000 |
Benefit Plans (Details)
Benefit Plans (Details) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | |
Pension and Other Postretirement Benefit Expense [Abstract] | |||
Pension cost | $ 8.7 | $ 13.5 | $ 11.9 |
Other postretirement benefit (income) expense | (12) | (11.9) | (13.7) |
Defined contribution plan, cost recognized | 6.5 | 6.6 | 6.4 |
Regulatory Liabilities [Line Items] | |||
Regulatory liabilities | 458.5 | 385.9 | |
Salaries, Wages and Officers' Compensation [Abstract] | |||
Allocated share-based compensation expense | 4 | 4 | $ 3 |
Other postretirement benefits [Member] | |||
Regulatory Liabilities [Line Items] | |||
Regulatory liabilities | 63 | 51 | |
Regulatory liability, deferred for future rate treatment | 52 | 37.4 | |
Regulatory liability, being amortized | 11 | 13.6 | |
Pension Costs [Member] | |||
Regulatory Liabilities [Line Items] | |||
Regulatory liabilities | 21.3 | 8 | |
Regulatory liability, deferred for future rate treatment | $ 21.3 | $ 8 |
Transactions with Major Custo33
Transactions with Major Customers and Affiliates (Details) $ in Thousands | 1 Months Ended | 12 Months Ended | ||
Jan. 31, 2017USD ($) | Dec. 31, 2016USD ($)employee | Dec. 31, 2015USD ($) | Dec. 31, 2014USD ($) | |
Related Party Transaction [Line Items] | ||||
Advances to affiliate | $ 811,693 | $ 64,608 | ||
Related party transaction, rate | 0.39% | |||
Entity number of employees | employee | 0 | |||
Expenses, related party | $ 318,400 | 327,100 | $ 310,100 | |
Severance Costs | 7,400 | |||
Equity distributions | 440,000 | 536,000 | 411,000 | |
Cash contributions from parent | 502,000 | 652,000 | 267,000 | |
Affiliated Entity [Member] | ||||
Related Party Transaction [Line Items] | ||||
Operating revenues, related party | 11,200 | 4,600 | 8,300 | |
Purchases, related party | 4,300 | 6,000 | 10,500 | |
Expenses, related party | (4,300) | (5,700) | (6,600) | |
Williams Partners L.P. [Member] | ||||
Related Party Transaction [Line Items] | ||||
Advances to affiliate | 811,700 | 64,600 | ||
Williams Field Services [Member] | ||||
Related Party Transaction [Line Items] | ||||
Reimbursements and pre-payments for capital projects | 5,000 | |||
Acquired certain assets | 1,900 | |||
Subsequent Event [Member] | ||||
Related Party Transaction [Line Items] | ||||
Equity distributions | $ 100,000 | |||
Cash contributions from parent | $ 110,000 | |||
National Grid [Member] | ||||
Revenue, Major Customer [Line Items] | ||||
Operating revenues | 166,300 | 129,600 | 91,200 | |
Public Service Enterprise Group [Member] | ||||
Revenue, Major Customer [Line Items] | ||||
Operating revenues | 143,600 | 110,200 | 115,300 | |
Duke Energy Corporation [Member] | ||||
Revenue, Major Customer [Line Items] | ||||
Operating revenues | $ 178,900 | $ 94,600 | $ 91,500 |
Asset Retirement Obligations (D
Asset Retirement Obligations (Details) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2016 | Dec. 31, 2015 | |
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | ||
Beginning balance | $ 323,026 | $ 296,475 |
Accretion | 35,740 | 25,178 |
New obligations | 7,995 | 256 |
Changes in estimates of existing obligations (1) | (85,514) | 3,691 |
Property dispositions/obligations settled | (5,795) | (2,574) |
Ending balance | 275,452 | 323,026 |
Annual funding obligation | 36,400 | |
Asset retirement obligation [Member] | ||
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | ||
Changes in estimates of existing obligations (1) | (86,000) | $ 4,000 |
External ARO trust [Member] | ||
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | ||
Annual funding obligation | $ 36,400 |
Regulatory Assets and Liabili35
Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions | Dec. 31, 2016 | Dec. 31, 2015 |
Regulatory Assets [Line Items] | ||
Regulatory assets | $ 351.1 | $ 343.3 |
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 458.5 | 385.9 |
Negative salvage | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 357.1 | 318.3 |
Sentinel meter station depreciation | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 6.2 | 6 |
Postretirement benefits other than pension | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 63 | 51 |
Electric power cost | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 6.3 | 0.8 |
Pension- deferred collections | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 21.3 | 8 |
Deferred gas costs | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 4.5 | 1.6 |
Other | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | 0.1 | 0.2 |
Grossed-up deferred taxes on equity funds used during construction | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 73.2 | 75.8 |
Asset retirement obligations | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 117.2 | 113.5 |
Asset retirement costs - Eminence | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 53.9 | 58.8 |
Deferred taxes | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 4.8 | 5.9 |
Deferred cash out | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 48.2 | 43.9 |
Fuel Cost | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 51.3 | 43.8 |
Other | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | $ 2.5 | $ 1.6 |
Other (Details)
Other (Details) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | |
Property, Plant and Equipment [Line Items] | |||
Capitalization of project feasibility costs previously expensed | $ 1.4 | $ 0 | $ 3.5 |