Document And Entity Information
Document And Entity Information - USD ($) | 12 Months Ended | |
Dec. 31, 2017 | Jun. 30, 2017 | |
Document Information [Line Items] | ||
Entity Registrant Name | OKLAHOMA GAS & ELECTRIC CO | |
Entity Central Index Key | 74,145 | |
Current Fiscal Year End Date | --12-31 | |
Entity Filer Category | Non-accelerated Filer | |
Document Type | 8-K | |
Document Period End Date | Dec. 31, 2017 | |
Document Fiscal Year Focus | 2,017 | |
Document Fiscal Period Focus | FY | |
Amendment Flag | false | |
Entity Common Stock, Shares Outstanding | 40,378,745 | |
Entity Well-known Seasoned Issuer | No | |
Entity Voluntary Filers | No | |
Entity Current Reporting Status | Yes | |
Entity Public Float | $ 0 |
STATEMENTS OF INCOME
STATEMENTS OF INCOME - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
OPERATING REVENUES | $ 2,261.1 | $ 2,259.2 | $ 2,196.9 |
COST OF SALES | 897.6 | 880.1 | 865 |
OPERATING EXPENSES | |||
Other operation and maintenance | 470.7 | 469 | 428.5 |
Depreciation and amortization | 280.9 | 316.4 | 299.9 |
Taxes other than income | 84.8 | 84 | 87.1 |
Total operating expenses | 836.4 | 869.4 | 815.5 |
OPERATING INCOME | 527.1 | 509.7 | 516.4 |
OTHER INCOME (EXPENSE) | |||
Allowance for equity funds used during construction | 39.7 | 14.2 | 8.3 |
Pension and Other Postretirement Benefits Cost (Reversal of Cost) | (15.4) | (0.8) | (16) |
Other income | 36.6 | 16.4 | 13.3 |
Other expense | (2.3) | (2.9) | (1.6) |
Net other income | 58.6 | 26.9 | 4 |
INTEREST EXPENSE | |||
Interest on long-term debt | 151.9 | 141.7 | 146.8 |
Allowance for borrowed funds used during construction | (18) | (7.5) | (4.2) |
Interest on short-term debt and other interest charges | 4.5 | 3.9 | 4.1 |
Interest expense | 138.4 | 138.1 | 146.7 |
INCOME BEFORE TAXES | 447.3 | 398.5 | 373.7 |
INCOME TAX EXPENSE | 141.8 | 114.4 | 104.8 |
NET INCOME | 305.5 | 284.1 | 268.9 |
Other comprehensive income (loss), net of tax | 0 | 0 | 0 |
COMPREHENSIVE INCOME | $ 305.5 | $ 284.1 | $ 268.9 |
STATEMENTS OF CASH FLOWS
STATEMENTS OF CASH FLOWS - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
CASH FLOWS FROM OPERATING ACTIVITIES | |||
Net income | $ 305.5 | $ 284.1 | $ 268.9 |
Adjustments to reconcile net income to net cash provided from operating activities: | |||
Depreciation and amortization | 280.9 | 316.4 | 299.9 |
Deferred income taxes and investment tax credits, net | 119.8 | 116.8 | 127.6 |
Allowance for equity funds used during construction | (39.7) | (14.2) | (8.3) |
Stock-based compensation expense | 3.1 | 2.3 | 2.6 |
Regulatory assets | 3.7 | (21.4) | (9.1) |
Regulatory liabilities | (3.7) | (11.8) | (27.5) |
Other assets | 1.6 | 13.7 | 10.1 |
Other liabilities | (59.9) | (20.1) | 22.2 |
Change in certain current assets and liabilities: | |||
Accounts receivable and accrued unbilled revenues, net | (22.2) | (6.1) | 17.7 |
Fuel, materials and supplies inventories | (5) | 32.5 | (56.2) |
Fuel recoveries | 53 | (112.6) | 129.6 |
Other current assets | 29.7 | (26.7) | (16) |
Accounts payable | 22.5 | (29.8) | 22.3 |
Income taxes payable - parent | 92 | (3.1) | (16.7) |
Other current liabilities | (65.6) | 52.9 | 3.4 |
Net Cash Provided from Operating Activities | 715.7 | 572.9 | 770.5 |
CASH FLOWS FROM INVESTING ACTIVITIES | |||
Capital expenditures (less allowance for equity funds used during construction) | (824.1) | (660.1) | (551.6) |
Proceeds from sale of assets | 0.7 | 0.9 | 2.6 |
Net cash used in investing activities | (823.4) | (659.2) | (549) |
CASH FLOWS FROM FINANCING ACTIVITIES | |||
Proceeds from long-term debt | 592.1 | 0 | 0 |
Changes in advances with parent | (189.3) | 351.5 | (101.3) |
Payment of long-term debt | (125.1) | (110.2) | (0.2) |
Dividends paid on common stock | (170) | (155) | (120) |
Net cash provided from (used in) financing activities | 107.7 | 86.3 | (221.5) |
NET CHANGE IN CASH AND CASH EQUIVALENTS | 0 | 0 | 0 |
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD | 0 | 0 | 0 |
CASH AND CASH EQUIVALENTS AT END OF PERIOD | $ 0 | $ 0 | $ 0 |
BALANCE SHEETS
BALANCE SHEETS - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 |
CURRENT ASSETS | ||
Accounts receivable, less reserve of $1.5 and $1.5, respectively | $ 188.5 | $ 173 |
Accrued unbilled revenues | 66.5 | 59.7 |
Advances to parent | 112.5 | 0 |
Fuel inventories | 84.3 | 79.8 |
Materials and supplies, at average cost | 80.8 | 80.3 |
Fuel clause under recoveries | 0 | 51.3 |
Other | 48.6 | 78.3 |
Total current assets | 581.2 | 522.4 |
OTHER PROPERTY AND INVESTMENTS | 5.9 | 6.6 |
PROPERTY, PLANT AND EQUIPMENT | ||
In service | 11,035.1 | 10,572.3 |
Construction work in progress | 867.5 | 495.1 |
Total property, plant and equipment | 11,902.6 | 11,067.4 |
Less accumulated depreciation | 3,568.8 | 3,385.6 |
Net property, plant and equipment | 8,333.8 | 7,681.8 |
DEFERRED CHARGES AND OTHER ASSETS | ||
Regulatory assets | 283 | 404.8 |
Other | 51.7 | 53.8 |
Total deferred charges and other assets | 334.7 | 458.6 |
TOTAL ASSETS | 9,255.6 | 8,669.4 |
CURRENT LIABILITIES | ||
Accounts payable - affiliates | 0.1 | 0.1 |
Accounts payable - other | 216.7 | 196.3 |
Advances from parent | 0 | 49.9 |
Customer deposits | 80.7 | 77.7 |
Accrued taxes | 41.5 | 40.8 |
Accrued interest | 44 | 40.2 |
Accrued compensation | 25.6 | 31.3 |
Long-term debt due within one year | 249.8 | 125 |
Fuel clause over recoveries | 1.7 | 0 |
Other | 28.5 | 95.8 |
Total current liabilities | 688.6 | 657.1 |
LONG-TERM DEBT | 2,749.6 | 2,405.8 |
DEFERRED CREDITS AND OTHER LIABILITIES | ||
Accrued benefit obligations | 110.3 | 167.7 |
Deferred income taxes | 832.2 | 1,752.3 |
Regulatory liabilities | 1,283.4 | 299.7 |
Other | 135.8 | 134.7 |
Total deferred credits and other liabilities | 2,361.7 | 2,354.4 |
Total liabilities | 5,799.9 | 5,417.3 |
COMMITMENTS AND CONTINGENCIES (NOTE 12) | ||
STOCKHOLDER'S EQUITY | ||
Common stockholder's equity | 1,027.2 | 1,024.1 |
Retained earnings | 2,428.5 | 2,228 |
Total stockholder's equity | 3,455.7 | 3,252.1 |
TOTAL LIABILITIES AND STOCKHOLDER'S EQUITY | $ 9,255.6 | $ 8,669.4 |
BALANCE SHEETS Parenthetical
BALANCE SHEETS Parenthetical - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 |
Accounts receivable reserve | $ 1.5 | $ 1.5 |
STATEMENTS OF CAPITALIZATION
STATEMENTS OF CAPITALIZATION - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 |
Stockholder's Equity [Abstract] | ||
Common stock, par value $2.50 per share; authorized 100.0 shares; and outstanding 40.4 shares and 40.4 shares, respectively | $ 100.9 | $ 100.9 |
Premium on common stock | 926.3 | 923.2 |
Retained earnings | 2,428.5 | 2,228 |
Total stockholder's equity | 3,455.7 | 3,252.1 |
Total long-term debt | 2,999.4 | 2,530.8 |
Less: long-term debt due within one year | (249.8) | (125) |
Total long-term debt (excluding debt due within one year) | 2,749.6 | 2,405.8 |
Total capitalization (including long-term debt due within one year) | 6,455.1 | 5,782.9 |
OG&E [Member] | ||
Stockholder's Equity [Abstract] | ||
Unamortized debt expense | (20.8) | (15.2) |
Unamortized discount | $ (9.9) | (9.3) |
OG&E [Member] | Series Due July 15, 2017 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 6.50% | |
Long term debt, gross | $ 0 | 125 |
OG&E [Member] | Series Due September 1, 2018 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 6.35% | |
Long term debt, gross | $ 250 | 250 |
OG&E [Member] | Series Due January 15, 2019 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 8.25% | |
Long term debt, gross | $ 250 | 250 |
OG&E [Member] | Series Due July 15, 2027 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 6.65% | |
Long term debt, gross | $ 125 | 125 |
OG&E [Member] | Series Due April 15, 2028 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 6.50% | |
Long term debt, gross | $ 100 | 100 |
OG&E [Member] | Series Due January 15, 2036 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 5.75% | |
Long term debt, gross | $ 110 | 110 |
OG&E [Member] | Series Due February 1, 2038 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 6.45% | |
Long term debt, gross | $ 200 | 200 |
OG&E [Member] | Series Due June 1, 2040 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 5.85% | |
Long term debt, gross | $ 250 | 250 |
OG&E [Member] | Senior Notes due May 15, 2041 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 5.25% | |
Long term debt, gross | $ 250 | 250 |
OG&E [Member] | Series due May 1, 2043 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 3.90% | |
Long term debt, gross | $ 250 | 250 |
OG&E [Member] | Series due March 15, 2044 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 4.55% | |
Long term debt, gross | $ 250 | 250 |
OG&E [Member] | Series due December 15, 2044 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 4.00% | |
Long term debt, gross | $ 250 | 250 |
OG&E [Member] | Due August 31, 2062 [Member] | Long-term Debt [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 3.70% | |
Long term debt, gross | $ 9.7 | 9.9 |
OG&E [Member] | Series due April 1, 2047 [Member] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 4.15% | |
Long term debt, gross | $ 300 | 0 |
OG&E [Member] | Series due August 15, 2047 [Member] [Domain] | Senior Notes [Member] | ||
Stockholder's Equity [Abstract] | ||
Debt Instrument, Interest Rate, Stated Percentage | 3.85% | |
Long term debt, gross | $ 300 | 0 |
Debentures Subject to Mandatory Redemption [Member] | ||
Stockholder's Equity [Abstract] | ||
Total long-term debt | 135.4 | |
Debentures Subject to Mandatory Redemption [Member] | OG&E [Member] | Garfield Industrial Authority Bond, Due January 1, 2025 [Member] | ||
Stockholder's Equity [Abstract] | ||
Long term debt, gross | 47 | 47 |
Debentures Subject to Mandatory Redemption [Member] | OG&E [Member] | Muskogee Industrial Authority Bond, Due January 1, 2025 [Member] | ||
Stockholder's Equity [Abstract] | ||
Long term debt, gross | 32.4 | 32.4 |
Debentures Subject to Mandatory Redemption [Member] | OG&E [Member] | Muskogee Industrial Authority Bond, Due June 1, 2027 [Member] | ||
Stockholder's Equity [Abstract] | ||
Long term debt, gross | $ 56 | $ 56 |
STATEMENTS OF CAPITALIZATION (P
STATEMENTS OF CAPITALIZATION (Parenthetical) - $ / shares shares in Millions | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Common Stock, Par or Stated Value Per Share | $ 2.50 | $ 2.50 |
Common Stock, Shares Authorized | 100 | 100 |
Common Stock, Shares, Outstanding | 40.4 | 40.4 |
Garfield Industrial Authority Bond, Due January 1, 2025 [Member] | ||
Debt Instrument, Maturity Date | Jan. 1, 2025 | |
Muskogee Industrial Authority Bond, Due January 1, 2025 [Member] | ||
Debt Instrument, Maturity Date | Jan. 1, 2025 | |
Muskogee Industrial Authority Bond, Due June 1, 2027 [Member] | ||
Debt Instrument, Maturity Date | Jun. 1, 2027 | |
Senior Notes [Member] | OG&E [Member] | Series Due January 15, 2016 [Member] | ||
Debt Instrument, Maturity Date | ||
Senior Notes [Member] | OG&E [Member] | Series Due July 15, 2017 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 6.50% | |
Debt Instrument, Maturity Date | Jul. 15, 2017 | |
Senior Notes [Member] | OG&E [Member] | Series Due September 1, 2018 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 6.35% | |
Debt Instrument, Maturity Date | Sep. 1, 2018 | |
Senior Notes [Member] | OG&E [Member] | Series Due January 15, 2019 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 8.25% | |
Debt Instrument, Maturity Date | Jan. 15, 2019 | |
Senior Notes [Member] | OG&E [Member] | Series Due July 15, 2027 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 6.65% | |
Debt Instrument, Maturity Date | Jul. 15, 2027 | |
Senior Notes [Member] | OG&E [Member] | Series Due April 15, 2028 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 6.50% | |
Debt Instrument, Maturity Date | Apr. 15, 2028 | |
Senior Notes [Member] | OG&E [Member] | Series Due January 15, 2036 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 5.75% | |
Debt Instrument, Maturity Date | Jan. 15, 2036 | |
Senior Notes [Member] | OG&E [Member] | Series Due February 1, 2038 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 6.45% | |
Debt Instrument, Maturity Date | Feb. 1, 2038 | |
Senior Notes [Member] | OG&E [Member] | Series Due June 1, 2040 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 5.85% | |
Debt Instrument, Maturity Date | Jun. 1, 2040 | |
Senior Notes [Member] | OG&E [Member] | Senior Notes due May 15, 2041 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 5.25% | |
Debt Instrument, Maturity Date | May 15, 2041 | |
Senior Notes [Member] | OG&E [Member] | Series due May 1, 2043 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 3.90% | |
Debt Instrument, Maturity Date | May 1, 2043 | |
Senior Notes [Member] | OG&E [Member] | Series due March 15, 2044 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 4.55% | |
Debt Instrument, Maturity Date | Mar. 15, 2044 | |
Senior Notes [Member] | OG&E [Member] | Series due December 15, 2044 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 4.00% | |
Debt Instrument, Maturity Date | Dec. 15, 2044 | |
Senior Notes [Member] | OG&E [Member] | Series due April 1, 2047 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 4.15% | |
Debt Instrument, Maturity Date | Apr. 1, 2047 | |
Senior Notes [Member] | OG&E [Member] | Series due August 15, 2047 [Member] [Domain] | ||
Debt Instrument, Interest Rate, Stated Percentage | 3.85% | |
Debt Instrument, Maturity Date | Aug. 15, 2047 | |
Long-term Debt [Member] | OG&E [Member] | Due August 31, 2062 [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 3.70% | |
Debt Instrument, Maturity Date | Aug. 31, 2062 | |
Minimum [Member] | Garfield Industrial Authority Bond, Due January 1, 2025 [Member] | Debentures Subject to Mandatory Redemption [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 0.65% | |
Minimum [Member] | Muskogee Industrial Authority Bond, Due January 1, 2025 [Member] | Debentures Subject to Mandatory Redemption [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 0.65% | |
Minimum [Member] | Muskogee Industrial Authority Bond, Due June 1, 2027 [Member] | Debentures Subject to Mandatory Redemption [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 0.66% | |
Maximum [Member] | Garfield Industrial Authority Bond, Due January 1, 2025 [Member] | Debentures Subject to Mandatory Redemption [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 1.86% | |
Maximum [Member] | Muskogee Industrial Authority Bond, Due January 1, 2025 [Member] | Debentures Subject to Mandatory Redemption [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 1.80% | |
Maximum [Member] | Muskogee Industrial Authority Bond, Due June 1, 2027 [Member] | Debentures Subject to Mandatory Redemption [Member] | ||
Debt Instrument, Interest Rate, Stated Percentage | 1.80% |
STATEMENTS OF CHANGES IN STOCKH
STATEMENTS OF CHANGES IN STOCKHOLDER'S EQUITY - USD ($) shares in Millions, $ in Millions | Total | Common Stock | Premium on Common Stock | Retained Earnings |
Balance, shares | 40.4 | |||
Dividends declared on common stock, shares | 0 | |||
Net income, shares | 0 | |||
Balance at Dec. 31, 2014 | $ 3,004.2 | $ 100.9 | $ 918.3 | $ 1,985 |
Comprehensive income (loss) | ||||
Net income | 268.9 | 0 | 0 | 268.9 |
Dividends declared on common stock | (120) | $ 0 | 0 | (120) |
Stock-based compensation, shares | 0 | |||
Stock-based compensation | 2.6 | $ 0 | 2.6 | 0 |
Balance at Dec. 31, 2015 | 3,155.7 | $ 100.9 | 920.9 | 2,133.9 |
Balance, shares | 40.4 | |||
Dividends declared on common stock, shares | 0 | |||
Net income, shares | 0 | |||
Comprehensive income (loss) | ||||
Net income | 284.1 | $ 0 | 0 | 284.1 |
Dividends declared on common stock | (190) | $ 0 | 0 | (190) |
Stock-based compensation, shares | 0 | |||
Stock-based compensation | 2.3 | $ 0 | 2.3 | 0 |
Balance at Dec. 31, 2016 | $ 3,252.1 | $ 100.9 | 923.2 | 2,228 |
Balance, shares | 40.4 | 40.4 | ||
Dividends declared on common stock, shares | 0 | |||
Net income, shares | 0 | |||
Comprehensive income (loss) | ||||
Net income | $ 305.5 | $ 0 | 0 | 305.5 |
Dividends declared on common stock | (105) | $ 0 | 0 | (105) |
Stock-based compensation, shares | 0 | |||
Stock-based compensation | 3.1 | $ 0 | 3.1 | 0 |
Balance at Dec. 31, 2017 | $ 3,455.7 | $ 100.9 | $ 926.3 | $ 2,428.5 |
Balance, shares | 40.4 | 40.4 |
Summary of Significant Accounti
Summary of Significant Accounting Policies | 12 Months Ended |
Dec. 31, 2017 | |
Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] | Summary of Significant Accounting Policies Organization OG&E generates, transmits, distributes and sells electric energy in Oklahoma and western Arkansas . Its operations are subject to regulation by the OCC, the APSC and the FERC. OG&E was incorporated in 1902 under the laws of the Oklahoma Territory . OG&E is the largest electric utility in Oklahoma, and its franchised service territory includes Fort Smith, Arkansas and the surrounding communities. OG&E sold its retail natural gas business in 1928 and is no longer engaged in the natural gas distribution business. OG&E is a wholly-owned subsidiary of OGE Energy, an energy and energy services provider offering physical delivery and related services for both electricity and natural gas primarily in the south central U.S. Use of Estimates In preparing the Financial Statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and contingent liabilities at the date of the Financial Statements and the reported amounts of revenues and expenses during the reporting period. Changes to these assumptions and estimates could have a material effect on OG&E's Financial Statements. However, OG&E believes it has taken reasonable positions where assumptions and estimates are used in order to minimize the negative financial impact to OG&E that could result if actual results vary from the assumptions and estimates. In management's opinion, the areas of OG&E where the most significant judgment is exercised includes the determination of Pension Plan assumptions, income taxes, contingency reserves, asset retirement obligations , depreciable lives of property, plant and equipment , regulatory assets and liabilities and unbilled revenues . Cash and Cash Equivalents For purposes of the Financial Statements, OG&E considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. These investments are carried at cost, which approximates fair value. Allowance for Uncollectible Accounts Receivable Customer balances are generally written off if not collected within six months after the final billing date. The allowance for uncollectible accounts receivable for OG&E is calculated by multiplying the last six months of electric revenue by the provision rate, which is based on a 12-month historical average of actual balances written off. To the extent the historical collection rates are not representative of future collections, there could be an effect on the amount of uncollectible expense recognized. Also, a portion of the uncollectible provision related to fuel within the Oklahoma jurisdiction is being recovered through the fuel adjustment clause. The allowance for uncollectible accounts receivable is a reduction to Accounts Receivable on the Balance Sheets and is included in the Other Operation and Maintenance Expense on the Statements of Income. The allowance for uncollectible accounts receivable was $1.5 million at both December 31, 2017 and 2016 . New business customers are required to provide a security deposit in the form of cash, bond or irrevocable letter of credit that is refunded when the account is closed. New residential customers whose outside credit scores indicate an elevated risk are required to provide a security deposit that is refunded based on customer protection rules defined by the OCC and the APSC. The payment behavior of all existing customers is continuously monitored, and, if the payment behavior indicates sufficient risk within the meaning of the applicable utility regulation, customers will be required to provide a security deposit. Depreciation and Amortization The provision for depreciation, which was 2.5 percent and 3.0 percent of the average depreciable utility plant for 2017 and 2016 , respectively, is calculated using the straight-line method over the estimated service life of the utility assets. Depreciation is provided at the unit level for production plant and at the account or sub-account level for all other plant and is based on the average life group method. In 2018 , the provision for depreciation is projected to be 2.7 percent of the average depreciable utility plant. Amortization of intangible assets is calculated using the straight-line method. Of the remaining amortizable intangible plant balance at December 31, 2017 , 98.6 percent will be amortized over 10.4 years with the remaining 1.4 percent of the intangible plant balance at December 31, 2017 being amortized over 23.7 years. Amortization of plant acquisition adjustments is provided on a straight-line basis over the estimated remaining service life of the acquired asset. Plant acquisition adjustments include $148.3 million for the Redbud Plant, which is being amortized over a 27 year life and $3.3 million for certain transmission substation facilities in OG&E's service territory, which are being amortized over a 37 to 59 year period. Allowance for Funds Used During Construction Allowance for funds used during construction, a non-cash item, is reflected as an increase to net Other Income and a reduction to Interest Expense in the Statements of Income and as an increase to Construction Work in Progress in the Balance Sheets. Allowance for funds used during construction is calculated according to the FERC requirements for the imputed cost of equity and borrowed funds. Allowance for funds used during construction rates, compounded semi-annually, were 8.2 percent , 8.2 percent and 8.1 percent for the years ended December 31, 2017 , 2016 and 2015 , respectively. Collection of Sales Tax In the normal course of its operations, OG&E collects sales tax from its customers. OG&E records a current liability for sales taxes when it bills its customers and eliminates this liability when the taxes are remitted to the appropriate governmental authorities. OG&E excludes the sales tax collected from its operating revenues. Revenue Recognition General OG&E recognizes revenue from electric sales when power is delivered to customers. OG&E reads its customers' meters and sends bills to its customers throughout each month. As a result, there is a significant amount of customers' electricity consumption that has not been billed at the end of each month. OG&E accrues an estimate of the revenues for electric sales delivered since the latest billings. Unbilled revenue is presented in Accrued Unbilled Revenues on the Balance Sheets and in Operating Revenues on the Statements of Income based on estimates of usage and prices during the period. The estimates that management uses in this calculation could vary from the actual amounts to be paid by customers. SPP Purchases and Sales OG&E currently owns and operates transmission and generation facilities as part of a vertically integrated utility. OG&E is a member of the SPP regional transmission organization and has transferred operational authority, but not ownership, of OG&E's transmission facilities to the SPP. The SPP has implemented FERC-approved regional day-ahead and real-time markets for energy and operating services, as well as associated transmission congestion rights. Collectively, the three markets operate together under the global name, SPP Integrated Marketplace. OG&E represents owned- and contracted-generation assets and customer load in the SPP Integrated Marketplace for the sole benefit of its customers. OG&E has not participated in the SPP Integrated Marketplace for any speculative trading activities. OG&E records the SPP Integrated Marketplace transactions as sales or purchases per FERC Order 668, which requires that purchases and sales be recorded on a net basis for each settlement period of the SPP Integrated Marketplace. These results are reported as Operating Revenues or Cost of Sales in the Financial Statements. OG&E revenues, expenses, assets and liabilities may be adversely affected by changes in the organization, operating and regulation by the FERC or the SPP. Fuel Adjustment Clauses The actual cost of fuel used in electric generation and certain purchased power costs are passed through to OG&E's customers through fuel adjustment clauses. The fuel adjustment clauses are subject to periodic review by the OCC and the APSC. Income Taxes OG&E is a member of an affiliated group that file s consolidated income tax returns in the U.S. federal jurisdiction and various state jurisdictions . Income taxes are generally allocated to each company in the affiliated group based on its stand-alone taxable income or loss. Federal investment tax credits previously claimed on electric utility property have been deferred and are being amortized to income over the life of the related property. OG&E uses the asset and liability method of accounting for income taxes. Under this method, a deferred tax asset or liability is recognized for the estimated future tax effects attributable to temporary differences between the financial statement basis and the tax basis of assets and liabilities as well as tax credit carry forwards and net operating loss carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the period of the change. OG&E recognizes interest related to unrecognized tax benefits in Interest Expense and recognizes penalties in Other Expense in the Statements of Income. On December 22, 2017, President Trump signed the 2017 Tax Act into law, significantly changing U.S. corporate income tax laws. The 2017 Tax Act reduces the corporate federal tax rate from 35 percent to 21 percent for tax years beginning after December 31, 2017. See Note 7 for further discussion of the effects of the 2017 Tax Act. Accrued Vacation OG&E accrues vacation pay monthly by establishing a liability for vacation earned. Vacation may be taken as earned and is charged against the liability. At the end of each year, the liability represents the amount of vacation earned but not taken. Environmental Costs Accruals for environmental costs are recognized when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated. Costs are charged to expense or deferred as a regulatory asset based on expected recovery from customers in future rates, if they relate to the remediation of conditions caused by past operations or if they are not expected to mitigate or prevent contamination from future operations. Where environmental expenditures relate to facilities currently in use, such as pollution control equipment, the costs may be capitalized and depreciated over the future service periods. Estimated remediation costs are recorded at undiscounted amounts, independent of any insurance or rate recovery, based on prior experience, assessments and current technology. Accrued obligations are regularly adjusted as environmental assessments and estimates are revised and remediation efforts proceed. For sites where OG&E has been designated as one of several potentially responsible parties, the amount accrued represents OG&E's estimated share of the cost. OG&E had $17.1 million and $13.9 million in accrued environmental liabilities at December 31, 2017 and 2016 , respectively, which are included in OG&E's asset retirement obligations. |
Schedule of Regulatory Assets and Liabilities [Text Block] | Accounting Records The accounting records of OG&E are maintained in accordance with the Uniform System of Accounts prescribed by the FERC and adopted by the OCC and the APSC. Additionally, OG&E, as a regulated utility, is subject to accounting principles for certain types of rate-regulated activities, which provide that certain incurred costs that would otherwise be charged to expense can be deferred as regulatory assets, based on the expected recovery from customers in future rates. Likewise, certain actual or anticipated credits that would otherwise reduce expense can be deferred as regulatory liabilities, based on the expected flowback to customers in future rates. Management's expected recovery of deferred costs and flowback of deferred credits generally results from specific decisions by regulators granting such ratemaking treatment. OG&E records certain incurred costs and obligations as regulatory assets or liabilities if, based on regulatory orders or other available evidence, it is probable that the costs or obligations will be included in amounts allowable for recovery or refund in future rates. The following table is a summary of OG&E's regulatory assets and liabilities: December 31 (In millions) 2017 2016 Regulatory Assets Current: Oklahoma demand program rider under recovery (A) $ 31.6 $ 51.0 SPP cost tracker under recovery (A) 7.7 10.0 Fuel clause under recoveries — 51.3 Other (A) 1.5 9.5 Total current regulatory assets $ 40.8 $ 121.8 Non-current: Benefit obligations regulatory asset $ 177.2 $ 232.6 Deferred storm expenses 42.2 35.7 Smart Grid 32.8 43.2 Unamortized loss on reacquired debt 12.3 13.4 Income taxes recoverable from customers, net — 62.3 Other 18.5 17.6 Total non-current regulatory assets $ 283.0 $ 404.8 Regulatory Liabilities Current: Fuel clause over recoveries $ 1.7 $ — Other (B) 2.2 12.3 Total current regulatory liabilities $ 3.9 $ 12.3 Non-current: Income taxes refundable to customers, net $ 955.5 $ — Accrued removal obligations, net 288.4 262.8 Pension tracker 32.3 35.5 Other 7.2 1.4 Total non-current regulatory liabilities $ 1,283.4 $ 299.7 (A) Included in Other Current Assets on the Balance Sheets. (B) Included in Other Current Liabilities on the Balance Sheets. OG&E recovers program costs related to the Demand and Energy Efficiency Program. An extension of the demand program rider was approved in January 2016, which allows for the recovery through December 2018 of (i) energy efficiency program costs, (ii) lost revenues associated with certain achieved energy efficiency and demand savings, (iii) performance-based incentives and (iv) costs associated with research and development investments. OG&E recovers certain SPP costs related to base plan charges from its customers and refunds certain SPP revenues received to its customers in Oklahoma through the SPP cost tracker. Fuel clause under recoveries are generated from under recoveries from OG&E's customers when OG&E's cost of fuel exceeds the amount billed to its customers. Fuel clause over recoveries are generated from over recoveries from OG&E's customers when the amount billed to its customers exceeds OG&E's cost of fuel. OG&E's fuel recovery clauses are designed to smooth the impact of fuel price volatility on customers' bills. As a result, OG&E under recovers fuel costs in periods of rising fuel prices above the baseline charge for fuel and over recovers fuel costs when prices decline below the baseline charge for fuel. Provisions in the fuel clauses are intended to allow OG&E to amortize under and over recovery balances. The benefit obligations regulatory asset is comprised of expenses recorded which are probable of future recovery and that have not yet been recognized as components of net periodic benefit cost, including net loss and prior service cost. These expenses are recorded as a regulatory asset as OG&E had historically recovered and currently recovers pension and postretirement benefit plan expense in its electric rates. If, in the future, the regulatory bodies indicate a change in policy related to the recovery of pension and postretirement benefit plan expenses, this could cause the benefit obligations regulatory asset balance to be reclassified to accumulated other comprehensive income. The following table is a summary of the components of the benefit obligations regulatory asset: December 31 (In millions) 2017 2016 Pension Plan and Restoration of Retirement Income Plan: Net loss $ 172.4 $ 199.9 Postretirement Benefit Plans: Net loss 33.6 32.7 Prior service cost (28.8 ) — Total $ 177.2 $ 232.6 The following amounts in the benefit obligations regulatory asset at December 31, 2017 are expected to be recognized as components of net periodic benefit cost in 2018 : (In millions) Pension Plan and Restoration of Retirement Income Plan: Net loss $ 12.5 Postretirement Benefit Plans: Net loss 4.0 Prior service cost (6.1 ) Total $ 10.4 OG&E includes in expense any Oklahoma storm-related operation and maintenance expenses up to $2.7 million annually and defers any additional expenses incurred over $2.7 million . OG&E expects to recover the amounts deferred each year over a five-year period in accordance with historical practice. OG&E previously recovered the cost of system-wide deployment of smart grid technology and implementing the smart grid pilot program through a rider. Costs not included in the rider are the incremental costs for web portal access, education and home energy reports, which are capped at $6.9 million , and the stranded costs associated with OG&E's analog electric meters, which have been replaced by smart meters. These incremental and stranded costs were accumulated during the smart grid deployment and have been included in the Smart Grid asset in the regulatory assets and liabilities table above. As approved in the recent Oklahoma rate case effective May 1, 2017, these costs are now being recovered over a six year period. Unamortized loss on reacquired debt is comprised of unamortized debt issuance costs related to the early retirement of OG&E's long-term debt. These amounts are recorded in interest expenses and are being amortized over the term of the long-term debt which replaced the previous long-term debt. The unamortized loss on reacquired debt is recovered as a part of OG&E's cost of capital. Income taxes refundable to customers, net, represent the reduction in accumulated deferred income taxes resulting from the reduction in the federal income tax rate, as part of the 2017 Tax Act. These amounts will be returned to customers in varying amounts over approximately 80 years. Currently, those amounts are shown net of income taxes recoverable from customers, which represents income tax benefits previously used to reduce OG&E's revenues, are treated as regulatory assets and are being amortized over the estimated remaining life of the assets to which they relate. These amounts are being recovered in rates as the temporary differences that generated the income tax benefit turn around. Accrued removal obligations, net represent asset retirement costs previously recovered from ratepayers for other than legal obligations. OG&E recovers specific amounts of pension and postretirement medical costs in rates approved in its Oklahoma rate cases. In accordance with approved orders, OG&E defers the difference between actual pension and postretirement medical expenses and the amount approved in its last Oklahoma rate case as a regulatory asset or regulatory liability. These amounts have been recorded in the Pension tracker regulatory liability in the regulatory assets and liabilities table above. Management continuously monitors the future recoverability of regulatory assets. When, in management's judgment, future recovery becomes impaired, the amount of the regulatory asset is adjusted, as appropriate. If OG&E were required to discontinue the application of accounting principles for certain types of rate-regulated activities for some or all of its operations, it could result in writing off the related regulatory assets, which could have significant financial effects. |
Inventory Disclosure [Text Block] | Fuel Inventories Fuel inventories for the generation of electricity consist of coal, natural gas and oil. OG&E uses the weighted-average cost method of accounting for inventory that is physically added to or withdrawn from storage or stockpiles. The amount of fuel inventory was $84.3 million and $82.4 million at December 31, 2017 and 2016 , respectively. Effective May 1, 2014, the gas storage services agreement with Enable was terminated. As a result of this contract termination, approximately 5.3 Bcf of cushion gas owned by OG&E and stored on the Enable system is being directed to OG&E's power plants over a five-year period during peak time of June 1 to August 31 at a rate of 11,500 MMBtu/day for a total of 1.06 Bcf per year. In 2014, approximately $11.0 million of cushion gas was reclassified from Plant-in-Service to Other Deferred Assets, representing natural gas in storage that will be removed from storage over four years. As of December 31, 2017 , the remaining balance of cushion gas of $2.8 million is included in Fuel Inventories . |
Property, Plant and Equipment Disclosure [Text Block] | Property, Plant and Equipment All property, plant and equipment is recorded at cost. Newly constructed plant is added to plant balances at cost which includes contracted services, direct labor, materials, overhead, transportation costs and the allowance for funds used during construction. Replacements of units of property are capitalized as plant. For assets that belong to a common plant account, the replaced plant is removed from plant balances, and the cost of such property is charged to Accumulated Depreciation. For assets that do not belong to a common plant account, the replaced plant is removed from plant balances with the related accumulated depreciation, and the remaining balance net of any salvage proceeds is recorded as a loss in the Statements of Income as Other Expense. Repair and replacement of minor items of property are included in the Statements of Income as Other Operation and Maintenance Expense. The tables below present OG&E's ownership interest in the jointly-owned McClain Plant and the jointly-owned Redbud Plant, and, as disclosed below, only OG&E's ownership interest is reflected in the property, plant and equipment and accumulated depreciation balances in these tables. The owners of the remaining interests in the McClain Plant and the Redbud Plant are responsible for providing their own financing of capital expenditures. Also, only OG&E's proportionate interests of any direct expenses of the McClain Plant and the Redbud Plant, such as fuel, maintenance expense and other operating expenses, are included in the applicable financial statement captions in the Statements of Income. December 31, 2017 (In millions) Percentage Ownership Total Property, Plant and Equipment Accumulated Depreciation Net Property, Plant and Equipment McClain Plant (A) 77 % $ 226.8 $ 71.4 $ 155.4 Redbud Plant (A)(B) 51 % $ 496.6 $ 136.0 $ 360.6 (A) Construction work in progress was $0.4 million and $7.8 million for the McClain and Redbud Plants, respectively. (B) This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $50.8 million . December 31, 2016 (In millions) Percentage Ownership Total Property, Plant and Equipment Accumulated Depreciation Net Property, Plant and Equipment McClain Plant (A) 77 % $ 234.2 $ 72.3 $ 161.9 Redbud Plant (A)(B) 51 % $ 489.0 $ 121.0 $ 368.0 (A) Construction work in progress was $0.2 million and $1.8 million for the McClain and Redbud Plants, respectively. (B) This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $45.3 million . OG&E's property, plant and equipment and related accumulated depreciation are divided into the following major classes: December 31, 2017 (In millions) Total Property, Plant and Equipment Accumulated Depreciation Net Property, Plant and Equipment Distribution assets $ 4,057.1 $ 1,259.1 $ 2,798.0 Electric generation assets (A) 4,475.0 1,493.5 2,981.5 Transmission assets (B) 2,767.7 506.5 2,261.2 Intangible plant 181.8 135.8 46.0 Other property and equipment 421.0 173.9 247.1 Total property, plant and equipment $ 11,902.6 $ 3,568.8 $ 8,333.8 (A) This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $50.8 million . (B) This amount includes a plant acquisition adjustment of $3.3 million and accumulated amortization of $0.6 million . December 31, 2016 (In millions) Total Property, Plant and Equipment Accumulated Depreciation Net Property, Plant and Equipment Distribution assets $ 3,896.2 $ 1,221.5 $ 2,674.7 Electric generation assets (A) 4,155.9 1,493.3 2,662.6 Transmission assets (B) 2,548.8 481.3 2,067.5 Intangible plant 85.0 43.9 41.1 Other property and equipment 381.5 145.6 235.9 Total property, plant and equipment $ 11,067.4 $ 3,385.6 $ 7,681.8 (A) This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $45.3 million . (B) This amount includes a plant acquisition adjustment of $3.3 million and accumulated amortization of $0.6 million . OG&E's unamortized computer software costs, included in intangible plant above, were $37.5 million and $36.5 million at December 31, 2017 and 2016 , respectively. In 2017 , 2016 and 2015 , amortization expense for computer software costs was $8.8 million , $8.0 million and $6.9 million , respectively. |
Asset Retirement Obligation Disclosure [Text Block] | Asset Retirement Obligations OG&E has asset retirement obligations primarily associated with the removal of company-owned wind turbines on leased land, as well as the removal of asbestos from certain power generating stations. OG&E has recorded asset retirement obligations that are being accreted over their respective lives ranging from three to 74 years. The following table summarizes changes to OG&E's asset retirement obligations during the years ended December 31, 2017 and 2016 . (In millions) 2017 2016 Balance at January 1 $ 69.6 $ 63.3 Accretion expense 3.1 2.8 Revisions in estimated cash flows (A) 2.4 3.6 Liabilities settled — (0.1 ) Balance at December 31 $ 75.1 $ 69.6 (A) Assumptions changed related to the estimated timing of asbestos abatement and estimated cost of ash pond removal at two of OG&E's generating facilities. |
Accounting Pronouncement
Accounting Pronouncement | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Pronouncement [Abstract] | |
New Accounting Pronouncements and Changes in Accounting Principles [Text Block] | Accounting Pronouncements Revenue from Contracts with Customers. In May 2014, the FASB issued ASU 2014-09, "Revenue from Contracts with Customers (Topic 606)." The new revenue standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 2017. OG&E has assessed the effect of this new guidance on its tariff-based sales, bundled arrangements and alternative revenue programs and is not aware of any issues that would have a material impact on the timing of revenue recognition. The new standard will not have a material impact on OG&E's results of operations and financial position but will change the income statement presentation of revenues and require new disclosures. OG&E adopted the new standard beginning in the first quarter of 2018 utilizing the modified retrospective transition method. Leases. In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)." The main difference between current lease accounting and Topic 842 is the recognition of right-of-use assets and lease liabilities by lessees for those leases classified as operating leases under current accounting guidance. Lessees, such as OG&E , will need to recognize a right-of-use asset and a lease liability for virtually all of their leases, other than leases that meet the definition of a short-term lease. The liability will be equal to the present value of lease payments. The asset will be based on the liability, subject to adjustment, such as for initial direct costs. For income statement purposes, Topic 842 retains a dual model, requiring leases to be classified as either operating or finance. Operating leases will result in straight-line expense, while finance leases will result in a front-loaded expense pattern, similar to current capital leases. Classification of operating and finance leases will be based on criteria that are largely similar to those applied in current lease guidance but without the explicit thresholds. The new guidance is effective for fiscal years beginning after December 2018. The new guidance must be adopted using a modified retrospective transition method and provides for certain practical expedients. Transition will require application of the new guidance at the beginning of the earliest comparative period presented. OG&E has started evaluating its current lease contracts. OG&E has not quantified the impact on its Financial Statements, but it anticipates an increase in the recognition of right-of-use assets and lease liabilities. In January 2018, the FASB issued ASU 2018-01, "Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842," which is an amendment to ASU 2016-02. Land easements (also commonly referred to as rights of way) represent the right to use, access or cross another entity's land for a specified purpose. This new guidance permits an entity to elect a transitional practical expedient, to be applied consistently, to not evaluate under Topic 842 land easements that exist or expired before the entity's adoption of Topic 842 and that were not previously accounted for as leases under ASC 840, "Leases." Once Topic 842 is adopted, an entity is required to apply Topic 842 prospectively to all new (or modified) land easements to determine whether the arrangement should be accounted for as a lease. ASU 2018-01 is effective for fiscal years beginning after December 2018. OG&E intends to elect this practical expedient during its adoption of Topic 842. Employee Share-based Payment Accounting. In March 2016, the FASB issued ASU 2016-09, "Improvements to Employee Share-Based Payment Accounting," which amends ASC Topic 718, "Compensation - Stock Compensation." ASU 2016-09 includes provisions intended to simplify various aspects related to how share-based payments are accounted for and presented in the financial statements. OG&E adopted this standard in the first quarter of 2017. The new guidance, among other requirements, requires the following. • All of the tax effects related to share-based payments at settlement (or expiration) should be recorded through the income statement. Previously, tax benefits in excess of compensation cost, or windfalls, were recorded in equity, and tax deficiencies, or shortfalls, were recorded in equity to the extent of previous windfalls and then to the income statement. Under the new guidance, the windfall tax benefit is recorded when it arises, subject to normal valuation allowance considerations. This change is required to be applied on a modified retrospective basis, with a cumulative effect adjustment to opening retained earnings. Excess tax benefits are to be reported as operating activities on the statement of cash flows, which is a change from the previous requirement to present windfall tax benefits as an inflow from financing activities and an outflow from operating activities. Going forward, tax benefits in excess of compensation cost previously recorded in equity will be recorded within the income statement, and the related cash impact will be recorded as an operating activity within the statement of cash flows. • Employee taxes paid when an employer withholds shares for tax-withholding purposes should be classified as a financing activity in the statement of cash flows, and this change should be applied retrospectively. Going forward, shares withheld for employee taxes will be classified as a financing activity within the statement of cash flows. • A policy election between recognizing forfeited awards as they occur or estimating the number of awards expected to be forfeited should be made and disclosed. OG&E will continue to estimate forfeitures in accounting for stock-based compensation. Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. In May 2017, the FASB issued ASU 2017-07, "Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost." The new guidance is designed to improve the reporting of pension and other postretirement benefit costs by bifurcating the components of net benefit expense between those that are attributed to compensation for service and those that are not. The service cost component of benefit expense continues to be presented within operating income, but entities are now required to present the other components of benefit expense as non-operating within the income statement. Additionally, the new guidance only permits the capitalization of the service cost component of net benefit expense. OG&E adopted the new guidance beginning in the first quarter of 2018, and, as a result, presents the service cost component of net benefit expense in operating income and the other components of net benefit expense as non-operating within its Statements of Income. Further, as required by ASU 2017-07, OG&E adjusted prior year income statements presentation of the net benefit expense components, which were previously presented in total within Other Operation and Maintenance on OG&E's Statements of Income. OG&E elected the practical expedient allowed by ASU 2017-07 to utilize amounts disclosed in OG&E's retirement plans and postretirement benefit plans note for prior periods as the estimation basis for applying the retrospective presentation requirements. Also, as required by ASU 2017-07, OG&E only capitalizes the service cost component of net benefit expense, beginning in the first quarter of 2018. Capitalized amounts for prior periods were not adjusted, as this change was implemented on a prospective basis. |
Related-Party Transactions Rela
Related-Party Transactions Related-Party Transactions | 12 Months Ended |
Dec. 31, 2017 | |
Related Party Transaction [Line Items] | |
Related Party Transactions Disclosure [Text Block] | Related Party Transactions OGE Energy charged operating costs to OG&E of $134.4 million , $131.5 million and $123.0 million in 2017 , 2016 and 2015 , respectively. OGE Energy charges operating costs to OG&E based on several factors. Operating costs directly related to OG&E are assigned as such. Operating costs incurred for the benefit of OG&E are allocated either as overhead based primarily on labor costs or using the "Distrigas" method. OG&E entered into a contract with Enable to provide transportation services effective May 1, 2014. This transportation agreement grants Enable the responsibility of delivering natural gas to OG&E’s generating facilities and performing an imbalance service. With this imbalance service, in accordance with the cash-out provision of the contract, OG&E purchases gas from Enable when Enable’s deliveries exceed OG&E’s pipeline receipts. Enable purchases gas from OG&E when OG&E’s pipeline receipts exceed Enable’s deliveries. In 2016, OG&E entered into an additional gas transportation services contract with Enable which will be effective upon the conversion of units 4 and 5 at Muskogee from coal to gas. The following table summarizes related party transactions between OG&E and Enable during the years ended December 31, 2017 , 2016 and 2015 . Year Ended December 31 (In millions) 2017 2016 2015 Operating revenues: Electricity to power electric compression assets $ 14.0 $ 11.5 $ 13.8 Cost of sales: Natural gas transportation services $ 35.0 $ 35.0 $ 35.0 Natural gas purchases (sales) (2.1 ) 11.2 7.6 In 2017 , 2016 and 2015 , OG&E declared dividends to OGE Energy of $105.0 million , $190.0 million and $120.0 million , respectively . |
Fair Value Measurements
Fair Value Measurements | 12 Months Ended |
Dec. 31, 2017 | |
Fair Value Disclosures [Abstract] | |
Fair Value Measurements | Fair Value Measurements The classification of OG&E's fair value measurements requires judgment regarding the degree to which market data is observable or corroborated by observable market data. GAAP establishes a fair value hierarchy that prioritizes the inputs used to measure fair value based on observable and unobservable data. The hierarchy categorizes the inputs into three levels, with the highest priority given to quoted prices in active markets for identical unrestricted assets or liabilities (Level 1) and the lowest priority given to unobservable inputs (Level 3). Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The three levels defined in the fair value hierarchy are as follows: Level 1 inputs are quoted prices in active markets for identical unrestricted assets or liabilities that are accessible at the measurement date. Level 2 inputs are inputs other than quoted prices in active markets included within Level 1 that are either directly or indirectly observable at the reporting date for the asset or liability for substantially the full term of the asset or liability. Level 2 inputs include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Level 3 inputs are prices or valuation techniques for the asset or liability that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). Unobservable inputs reflect the reporting entity's own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). OG&E had no financial instruments measured at fair value on a recurring basis at December 31, 2017 and 2016 . The fair value of OG&E's long-term debt is based on quoted market prices and estimates of current rates available for similar issues with similar maturities and is classified as Level 2 in the fair value hierarchy with the exception of the Tinker Debt whose fair value is based on calculating the net present value of the monthly payments discounted by OG&E's current borrowing rate and is classified as Level 3 in the fair value hierarchy. The following table summarizes the fair value and carrying amount of OG&E's financial instruments at December 31, 2017 and 2016 . Year Ended December 31 (In millions) 2017 2016 Carrying Amount Fair Value Carrying Amount Fair Value Long-term Debt (including Long-term Debt due within one year): Senior Notes $ 2,854.3 $ 3,242.8 $ 2,385.5 $ 2,657.2 Industrial Authority Bonds 135.4 135.4 135.4 135.4 Tinker Debt 9.7 9.8 9.9 11.3 |
Stock-Based Compensation
Stock-Based Compensation | 12 Months Ended |
Dec. 31, 2017 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |
Disclosure of Compensation Related Costs, Share-based Payments [Text Block] | Stock-Based Compensation In 2013, OGE Energy adopted, and its shareholders approved, the Stock Incentive Plan. Under the Stock Incentive Plan, restricted stock, restricted stock units, stock options, stock appreciation rights and performance units may be granted to officers, directors and other key employees of OGE Energy and its subsidiaries. OGE Energy has authorized the issuance of up to 7,400,000 shares under the Stock Incentive Plan. The following table summarizes OG&E's pre-tax compensation expense and related income tax benefit for the year s ended December 31, 2017 , 2016 and 2015 related to performance units and restricted stock for OG&E employees . Year Ended December 31 (In millions) 2017 2016 2015 Performance units: Total shareholder return $ 2.5 $ 2.1 $ 2.4 Earnings per share 0.5 0.1 0.4 Total performance units 3.0 2.2 2.8 Restricted stock — — 0.1 Net compensation expense $ 3.0 $ 2.2 $ 2.9 Income tax benefit $ 1.2 $ 0.9 $ 1.1 OGE Energy has issued new shares to satisfy restricted stock grants and payouts of earned performance units. In 2017 , 2016 and 2015 , there were 965 shares , 1,131 shares and 18,820 shares , respectively, of new common stock issued to OG&E's employees pursuant to OGE Energy's Stock Incentive Plan related to restricted stock grants (net of forfeitures) and payouts of earned performance units. In 2017 , there were 146 shares of restricted stock returned to OGE Energy to satisfy tax liabilities. Performance Units Under the Stock Incentive Plan, OGE Energy has issued performance units which represent the value of one share of OGE Energy's common stock. The performance units provide for accelerated vesting if there is a change in control (as defined in the Stock Incentive Plan). Each performance unit is subject to forfeiture if the recipient terminates employment with OGE Energy or a subsidiary prior to the end of the primarily three-year award cycle for any reason other than death, disability or retirement. In the event of death, disability or retirement, a participant will receive a prorated payment based on such participant's number of full months of service during the award cycle, further adjusted based on the achievement of the performance goals during the award cycle. The performance units granted based on total shareholder return are contingently awarded and will be payable in shares of OGE Energy's common stock subject to the condition that the number of performance units, if any, earned by the employees upon the expiration of a primarily three-year award cycle (i.e., three-year cliff vesting period) is dependent on OGE Energy's total shareholder return ranking relative to a peer group of companies. The performance units granted based on earnings per share are contingently awarded and will be payable in shares of OGE Energy's common stock based on OGE Energy's earnings per share growth over a primarily three-year award cycle (i.e., three-year cliff vesting period) compared to a target set at the time of the grant by the Compensation Committee of OGE Energy's Board of Directors. All of these performance units are classified as equity in OGE Energy's Consolidated Balance Sheets. If there is no or only a partial payout for the performance units at the end of the award cycle, the unearned performance units are cancelled. Payout requires approval of the Compensation Committee of OGE Energy's Board of Directors. Payouts, if any, are all made in common stock and are considered made when the payout is approved by the Compensation Committee. Performance Units – Total Shareholder Return The fair value of the performance units based on total shareholder return was estimated on the grant date using a lattice-based valuation model that factors in information, including the expected dividend yield, expected price volatility, risk-free interest rate and the probable outcome of the market condition, over the expected life of the performance units. Compensation expense for the performance units is a fixed amount determined at the grant date fair value and is recognized over the primarily three-year award cycle regardless of whether performance units are awarded at the end of the award cycle. Dividends were not accrued or paid for awards prior to February 2014 and were therefore not included in the fair value calculation. Beginning with the February 2014 performance unit awards, dividends are accrued on a quarterly basis pending achievement of payout criteria and were therefore included in the fair value calculations. Expected price volatility is based on the historical volatility of OGE Energy's common stock for the past three years and was simulated using the Geometric Brownian Motion process. The risk-free interest rate for the performance unit grants is based on the three-year U.S. Treasury yield curve in effect at the time of the grant. The expected life of the units is based on the non-vested period since inception of the award cycle. There are no post-vesting restrictions related to OGE Energy's performance units based on total shareholder return. The number of performance units granted based on total shareholder return and the assumptions used to calculate the grant date fair value of the performance units based on total shareholder return are shown in the following table. 2017 2016 2015 Number of units granted to OG&E employees 85,501 105,076 90,098 Fair value of units granted $ 41.76 $ 20.84 $ 31.02 Expected dividend yield 3.8 % 3.5 % 2.6 % Expected price volatility 19.8 % 19.8 % 16.9 % Risk-free interest rate 1.46 % 0.88 % 0.91 % Expected life of units (in years) 2.86 2.85 2.85 Performance Units – Earnings Per Share The fair value of the performance units based on earnings per share is based on grant date fair value which is equivalent to the price of one share of OGE Energy's common stock on the date of grant. The fair value of performance units based on earnings per share varies as the number of performance units that will vest is based on the grant date fair value of the units and the probable outcome of the performance condition. OGE Energy reassesses at each reporting date whether achievement of the performance condition is probable and accrues compensation expense if and when achievement of the performance condition is probable. As a result, the compensation expense recognized for these performance units can vary from period to period. There are no post-vesting restrictions related to OGE Energy's performance units based on earnings per share. The number of performance units granted based on earnings per share and the grant date fair value are shown in the following table. 2017 2016 2015 Number of units granted to OG&E employees 28,499 35,025 30,034 Fair value of units granted $ 34.83 $ 26.59 $ 33.99 Restricted Stock Under the Stock Incentive Plan, OGE Energy issued restricted stock to certain existing non-officer employees as well as other executives upon hire to attract and retain individuals to be competitive in the marketplace. The restricted stock vests in one-third annual increments. Prior to vesting, each share of restricted stock is subject to forfeiture if the recipient ceases to render substantial services to OGE Energy or a subsidiary for any reason other than death, disability or retirement. These shares may not be sold, assigned, transferred or pledged and are subject to a risk of forfeiture. The fair value of the restricted stock was based on the closing market price of OGE Energy's common stock on the grant date. Compensation expense for the restricted stock is a fixed amount determined at the grant date fair value and is recognized as services are rendered by employees over a primarily three-year vesting period. Also, OG&E treats its restricted stock as multiple separate awards by recording compensation expense separately for each tranche whereby a substantial portion of the expense is recognized in the earlier years in the requisite service period. Dividends are accrued and paid during the vesting period on restricted stock granted prior to July 2014; therefore, dividends are included in the fair value calculation for such restricted stock granted prior to July 2014. For restricted stock granted after July 2014, dividends will only be paid on restricted stock awards that vest. Accordingly, for restricted stock granted after July 2014, only the present value of dividends expected to vest are included in the fair value calculations. The expected life of the restricted stock is based on the non-vested period since inception of the primarily three-year award cycle. There are no post-vesting restrictions related to OGE Energy's restricted stock. There were no restricted stock grants during 2017, 2016 or 2015. A summary of the activity for OGE Energy's performance units and restricted stock applicable to OG&E's employees at December 31, 2017 and changes in 2017 are shown in the following table. Performance Units Total Shareholder Return Earnings Per Share Restricted Stock (Dollars in millions) Number Aggregate Intrinsic Value Number Aggregate Intrinsic Value Number Aggregate Intrinsic Value Units/shares outstanding at 12/31/16 236,581 78,864 1,796 Granted 85,501 (A) 28,499 (A) — Converted (57,484 ) (B) $ — (19,164 ) (B) $ — N/A Vested N/A N/A (1,796 ) $ 0.1 Forfeited (7,805 ) (2,602 ) — Employee migration (4,543 ) (C) (1,514 ) (C) 625 Units/shares outstanding at 12/31/17 252,250 $ 0.9 84,083 $ 2.5 625 $ — Units/shares fully vested at 12/31/17 73,092 $ — 24,366 $ 0.4 (A) For performance units, this represents the target number of performance units granted. Actual number of performance units earned, if any, is dependent upon performance and may range from zero percent to 200 percent of the target. (B) These amounts represent performance units that vested at December 31, 2016 which were settled in February 2017. (C) Due to certain employees transferring between OG&E and OGE Energy. A summary of the activity for OGE Energy's non-vested performance units and restricted stock applicable to OG&E's employees at December 31, 2017 and changes in 2017 are shown in the following table. Performance Units Total Shareholder Return Earnings Per Share Restricted Stock Number Weighted-Average Number Weighted-Average Number Weighted-Average Units/shares non-vested at 12/31/16 179,097 $ 25.12 59,700 $ 29.70 1,796 $ 35.45 Granted 85,501 (A) $ 41.76 28,499 (A) $ 34.83 — $ — Vested (73,092 ) $ 31.02 (24,366 ) $ 33.99 (1,796 ) $ 35.38 Forfeited (7,805 ) $ 31.52 (2,602 ) $ 31.20 — $ — Employee migration (4,543 ) (B) $ 29.84 (1,514 ) (B) $ 31.09 625 $ 31.92 Units/shares non-vested at 12/31/17 179,158 $ 30.26 59,717 $ 30.30 625 $ 31.92 Units/shares expected to vest 172,618 (C) 57,592 (C) 625 (A) For performance units, this represents the target number of performance units granted. Actual number of performance units earned, if any, is dependent upon performance and may range from zero percent to 200 percent of the target. (B) Due to certain employees transferring between OG&E and OGE Energy. (C) The intrinsic value of the performance units based on total shareholder return and earnings per share is $0.9 million and $2.0 million , respectively. Fair Value of Vested Performance Units and Restricted Stock A summary of OG&E's fair value for its vested performance units and restricted stock is shown in the following table. Year Ended December 31 (In millions) 2017 2016 2015 Performance units: Total shareholder return $ 2.3 $ 2.0 $ 2.1 Earnings per share 0.4 — — Restricted stock 0.1 0.1 0.1 Unrecognized Compensation Cost A summary of OG&E's unrecognized compensation cost for its non-vested performance units and restricted stock and the weighted-average periods over which the compensation cost is expected to be recognized are shown in the following table. December 31, 2017 Unrecognized Compensation Cost (In millions) Weighted Average to be Recognized (In years) Performance units: Total shareholder return $ 2.9 1.77 Earnings per share 0.9 1.68 Total performance units 3.8 Restricted stock — 1.58 Total $ 3.8 |
Supplemental Cash Flow Informat
Supplemental Cash Flow Information | 12 Months Ended |
Dec. 31, 2017 | |
Supplemental Cash Flow Information [Abstract] | |
Cash Flow, Supplemental Disclosures [Text Block] | Supplemental Cash Flow Information The following table discloses information about investing and financing activities that affected recognized assets and liabilities but did not result in cash receipts or payments. Cash paid for interest, net of interest capitalized, and cash paid for income taxes, net of income tax refunds are also disclosed in the table. Year Ended December 31 (In millions) 2017 2016 2015 NON-CASH INVESTING AND FINANCING ACTIVITIES Power plant long-term service agreement $ 2.6 $ 39.5 $ 2.3 SUPPLEMENTAL CASH FLOW INFORMATION Cash paid during the period for: Interest (net of interest capitalized) (A) $ 133.1 $ 138.3 $ 143.6 Income taxes (net of income tax refunds) (71.5 ) — (6.2 ) (A) Net of interest capitalized of $18.0 million , $7.5 million and $4.2 million in 2017 , 2016 and 2015 , respectively. |
Income Taxes
Income Taxes | 12 Months Ended |
Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | |
Income Tax Disclosure Text Block | Income Taxes 2017 Tax Act On December 22, 2017, President Trump signed the 2017 Tax Act into law, significantly changing U.S. corporate income tax laws. The 2017 Tax Act reduces the corporate federal tax rate from 35 percent to 21 percent for tax years beginning after December 31, 2017. Among other things, the 2017 Tax Act repeals the alternative minimum tax regime for tax years beginning after December 31, 2017. For tax years beginning in 2018, 2019 and 2020, the alternative minimum tax credit carryforward can be utilized to offset regular tax with any remaining alternative minimum tax carryforwards eligible for a refund of 50 percent . Any remaining alternative minimum tax credit carryforwards will become fully refundable beginning in the 2021 tax year. The 2017 Tax Act also limits a taxpayer’s ability to utilize net operating loss carryforwards to 80 percent of taxable income. Additionally, net operating losses arising after 2017 can be carried forward indefinitely, but carryback is generally prohibited. Net operating losses generated in tax years beginning before January 1, 2018 will not be subject to the taxable income limitation and will continue to have a two year carryback and 20 year carryforward period. The 2017 Tax Act allows companies to expense 100 percent of the cost of qualified property placed in service after September 27, 2017 and before January 1, 2023 (an additional year is provided for certain property with longer production periods). The 100 percent expense provision is phased down by 20 percent per calendar year beginning in 2023 (i.e., 80 percent, 60 percent, 40 percent and 20 percent for calendar years 2023 through 2026, respectively), with normal depreciation rules applicable after that. The phase out begins in 2024 for certain property with longer production periods. Companies can elect not to immediately expense qualified assets. The 2017 Tax Act limits deductions for net interest expense to 30 percent of adjusted taxable income. The 2017 Tax Act repeals deductions for qualified domestic production activities, entertainment, amusement or recreation expenses, membership dues for clubs and expenses incurred for the use of facilities in connection with these items. The 2017 Tax Act retains the $1 million limitation on deductible compensation to covered employees. However, it eliminates the current exception for performance-based compensation and expands the definition of covered employees to include the chief financial officer. The new executive compensation limitations are effective in 2018, with certain transition rules. During 2017, OGE Energy fully utilized all remaining federal net operating losses and alternative minimum tax credits. Changes made by the 2017 Tax Act related to alternative minimum tax and net operating loss utilization are not expected to have a material impact on OGE Energy in the future. For regulated entities, such as OG&E, provisions in the 2017 Tax Act provide for unrestricted deduction of interest expense in lieu of full expensing of qualified property. OGE Energy will see some impact from other provisions related to non-deductible expenses, but those items are not expected to be material with respect to 2018. ASC 740, "Income Taxes," requires deferred tax assets and liabilities to be measured at the enacted tax rate expected to apply when temporary differences are to be realized or settled. Therefore, at December 31, 2017, OG&E remeasured deferred taxes based upon the new 21 percent tax rate. For entities subject to ASC 980, "Accounting for Regulated Entities," such as OG&E, those entities are required to recognize a regulatory liability for the decrease in taxes payable for the change in tax rates that are expected to be returned to customers through future rates and to recognize a regulatory asset for the increase in taxes receivable for the change in tax rates that are expected to be recovered from customers through future rates. As a result of remeasuring existing deferred taxes at the lower 21 percent tax rate, OG&E reduced net deferred income tax liabilities and increased regulatory liabilities, net by $1.038 billion . Staff Accounting Bulletin No. 118 On December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118 to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the 2017 Tax Act. OG&E has recognized the provisional tax impacts related to the revaluation of deferred tax assets and liabilities and included these amounts in its Financial Statements for the year ended December 31, 2017 . The ultimate impact may differ from these provisional amounts, possibly materially, due to, among other things, additional analysis, changes in interpretations and assumptions OG&E has made, additional regulatory guidance that may be issued and actions OG&E may take as a result of the 2017 Tax Act. Any subsequent adjustment to these amounts will be recorded to adjust the initial recognition of tax reform in the quarter of 2018 when the analysis is complete. The items comprising income tax (benefit) expense are as follows: Year Ended December 31 (In millions) 2017 2016 2015 Provision (benefit) for current income taxes: Federal $ 26.3 $ 2.9 $ (17.5 ) State (4.3 ) (5.3 ) (5.3 ) Total provision (benefit) for current income taxes 22.0 (2.4 ) (22.8 ) Provision for deferred income taxes, net: Federal 100.0 99.8 117.0 State 19.9 17.2 11.3 Total provision for deferred income taxes, net 119.9 117.0 128.3 Deferred federal investment tax credits, net (0.1 ) (0.2 ) (0.7 ) Total income tax expense $ 141.8 $ 114.4 $ 104.8 OG&E is a member of an affiliated group that file s consolidated income tax returns in the U.S. federal jurisdiction and various state jurisdictions . With few exceptions, OG&E is no longer subject to U.S. federal tax examinations by tax authorities for years prior to 2014 or state and local tax examinations by tax authorities for years prior to 2013 . Income taxes are generally allocated to each company in the affiliated group based on its stand-alone taxable income or loss. Federal investment tax credits previously claimed on electric utility property have been deferred and are being amortized to income over the life of the related property. OG&E earns both federal and Oklahoma state tax credits associated with production from its wind farms and earns state tax credits associated with its investments in electric generating facilities which reduce OG&E's effective tax rate. The following schedule reconciles the statutory tax rates to the effective income tax rate: Year Ended December 31 2017 2016 2015 Statutory federal tax rate 35.0 % 35.0 % 35.0 % State income taxes, net of federal income tax benefit 2.2 1.8 0.5 Amortization of net unfunded deferred taxes 0.9 0.8 0.9 Federal renewable energy credit (A) (6.1 ) (8.2 ) (8.8 ) Other (0.3 ) 0.1 (0.1 ) Uncertain tax positions — 0.1 0.7 Federal investment tax credits, net — (0.9 ) (0.2 ) Effective income tax rate 31.7 % 28.7 % 28.0 % (A) Represents credits associated with the production from OG&E's wind farms. The deferred tax provisions are recognized as costs in the ratemaking process by the commissions having jurisdiction over the rates charged by OG&E. The components of Deferred Income Taxes at December 31, 2017 and 2016 were as follows: December 31 (In millions) 2017 2016 Deferred income tax liabilities, net: Accelerated depreciation and other property related differences $ 1,449.6 $ 2,101.4 OG&E Pension Plan 28.4 48.0 Regulatory asset 18.9 34.4 Bond redemption-unamortized costs 2.6 4.3 Income taxes (recoverable from) refundable to customers, net (244.3 ) 24.1 Federal tax credits (218.3 ) (209.3 ) State tax credits (129.2 ) (102.6 ) Asset retirement obligations (19.2 ) (24.5 ) Postretirement medical and life insurance benefits (17.4 ) (34.3 ) Regulatory liabilities (16.8 ) (34.6 ) Net operating losses (11.2 ) (26.1 ) Other (4.8 ) (16.7 ) Accrued liabilities (3.8 ) (8.0 ) Accrued vacation (1.4 ) (2.4 ) Deferred federal investment tax credits (0.5 ) (0.8 ) Uncollectible accounts (0.4 ) (0.6 ) Total deferred income tax liabilities, net $ 832.2 $ 1,752.3 As of December 31, 2017 , OG&E has classified $16.4 million of unrecognized tax benefits as a reduction of deferred tax assets recorded. Management is currently unaware of any issues under review that could result in significant additional payments, accruals, or other material deviation from this amount. Following is a reconciliation of OG&E’s total gross unrecognized tax benefits as of the years ended December 31, 2017 , 2016 and 2015 . (In millions) 2017 2016 2015 Balance at January 1 $ 20.7 $ 20.2 $ 16.1 Tax positions related to current year: Additions — 0.5 4.1 Balance at December 31 $ 20.7 $ 20.7 $ 20.2 As of December 31, 2017 , 2016 and 2015 , there were $16.4 million , $13.5 million and $13.2 million of unrecognized tax benefits that, if recognized, would affect the annual effective tax rate. Where applicable, OG&E classifies income tax-related interest and penalties as interest expense and other expense, respectively. During the year ended December 31, 2017 , there were no income tax-related interest or penalties recorded with regard to uncertain tax positions. OG&E sustained federal and state tax operating losses through 2012 caused primarily by bonus depreciation and other book versus tax temporary differences. As a result, OG&E had accrued federal and state income tax benefits carrying into 2017 . During 2017, the remaining federal net operating loss was utilized. State operating losses are being carried forward for utilization in future years. In addition to the tax operating losses, OG&E was unable to utilize the various tax credits that were generated during these years. These tax losses and credits are being carried as deferred tax assets and will be utilized in future periods. Under current law, OG&E anticipates future taxable income will be sufficient to utilize remaining losses and credits before they begin to expire. The following table summarizes these carry forwards: (In millions) Carry Forward Amount Deferred Tax Asset Earliest Expiration Date State operating loss $ 250.5 $ 11.2 2030 Federal tax credits 218.3 218.3 2029 State tax credits: Oklahoma investment tax credits 128.2 101.3 N/A Oklahoma capital investment board credits 8.5 8.5 N/A Oklahoma zero emission tax credits 24.1 19.4 2020 |
Common Stock and Cumulative Pre
Common Stock and Cumulative Preferred Stock | 12 Months Ended |
Dec. 31, 2017 | |
Common Stock and Cumulative Preferred Stock [Abstract] | |
Common Stock and Cumulative Preferred Stock [Text Block] | Common Stock and Cumulative Preferred Stock There were no new shares of common stock issued in 2017 , 2016 or 2015 . |
Long-Term Debt
Long-Term Debt | 12 Months Ended |
Dec. 31, 2017 | |
Long-term Debt, Unclassified [Abstract] | |
Long-Term Debt | Long-Term Debt A summary of OG&E's long-term debt is included in the Statements of Capitalization. At December 31, 2017 , OG&E was in compliance with all of its debt agreements. Industrial Authority Bonds OG&E has tax-exempt pollution control bonds with optional redemption provisions that allow the holders to request repayment of the bonds on any business day. The bonds, which can be tendered at the option of the holder during the next 12 months, are as follows: SERIES DATE DUE AMOUNT (In millions) 0.65% - 1.86% Garfield Industrial Authority, January 1, 2025 $ 47.0 0.65% - 1.80% Muskogee Industrial Authority, January 1, 2025 32.4 0.66% - 1.80% Muskogee Industrial Authority, June 1, 2027 56.0 Total (redeemable during next 12 months) $ 135.4 All of these bonds are subject to an optional tender at the request of the holders, at 100 percent of the principal amount, together with accrued and unpaid interest to the date of purchase. The bond holders, on any business day, can request repayment of the bond by delivering an irrevocable notice to the tender agent stating the principal amount of the bond, payment instructions for the purchase price and the business day the bond is to be purchased. The repayment option may only be exercised by the holder of a bond for the principal amount. When a tender notice has been received by the trustee, a third party remarketing agent for the bonds will attempt to remarket any bonds tendered for purchase. This process occurs once per week. Since the original issuance of these series of bonds in 1995 and 1997, the remarketing agent has successfully remarketed all tendered bonds. If the remarketing agent is unable to remarket any such bonds, OG&E is obligated to repurchase such unremarketed bonds. As OG&E has both the intent and ability to refinance the bonds on a long-term basis and such ability is supported by an ability to consummate the refinancing, the bonds are classified as Long-Term Debt in OG&E's Financial Statements. OG&E believes that it has sufficient liquidity to meet these obligations. Long-Term Debt Maturities Maturities of OG&E's long-term debt during the next five years consist of $250.1 million , $250.1 million , $0.1 million , $0.1 million and $0.1 million in 2018 , 2019 , 2020 , 2021 and 2022 , respectively. OG&E has previously incurred costs related to debt refinancing. Unamortized loss on reacquired debt is classified as a Non-Current Regulatory Asset. Unamortized debt expense and unamortized premium and discount on long-term debt are classified as Long-Term Debt in the Balance Sheets and are being amortized over the life of the respective debt. Issuance of Long-Term Debt In March 2017, OG&E issued $300.0 million of 4.15 percent senior notes due April 1, 2047 . The proceeds from the issuance were used for general corporate purposes, including to repay short-term debt, to repay borrowings under the revolving credit facility, to fund the payment of OG&E's $125.0 million of 6.5 percent senior notes that matured on July 15, 2017 and to fund ongoing capital expenditures and working capital. In August 2017, OG&E issued $300.0 million of 3.85 percent senior notes due August 15, 2047 . The proceeds from the issuance were used for general corporate purposes, including to repay short-term debt, to repay borrowings under the revolving credit facility and to fund ongoing capital expenditures and working capital. |
Short-Term Debt and Credit Faci
Short-Term Debt and Credit Facility | 12 Months Ended |
Dec. 31, 2017 | |
Short-term Debt [Abstract] | |
Short-Term Debt and Credit Facility | Short-Term Debt and Credit Facility On March 8, 2017, OG&E entered into a new unsecured $450.0 million five-year revolving credit facility. The new facility is scheduled to terminate on March 8, 2022 . However, OG&E has the right to request an extension of the revolving credit facility termination date under its facility for an additional one-year period, which can be exercised up to two times. All such extension requests are subject to majority lender group approval (and only the commitments of those lenders that consent to such extension (or that agree to replace any non-consenting lender) will be extended for such additional period). Borrowings under OG&E’s new facility shall bear interest at rates equal to either the eurodollar base rate (reserve adjusted, if applicable), plus a margin of 0.69 percent to 1.275 percent , or an alternate base rate, plus a margin of 0.0 percent to 0.275 percent . OG&E’s new facility has a facility fee that ranges from 0.06 percent to 0.225 percent . Interest rate margins and facility fees are based on OG&E’s then-current senior unsecured credit ratings. The new facility provides for issuance of letters of credit, provided that (i) the aggregate outstanding credit exposure shall not exceed the amount of the revolving credit facility and (ii) the aggregate outstanding stated amount of letters of credit issued under such facility shall not exceed a sublimit of $100.0 million . Advances under the new facility may be used to refinance existing indebtedness and for working capital and general corporate purposes, including commercial paper liquidity support, letters of credit, acquisitions and distributions. The new facility is unsecured and, under certain circumstances, may be increased by up to $150.0 million , to a maximum revolving commitment limit of $600.0 million . Advances of revolving loans and letters of credit under the new facility are subject to certain conditions precedent, including the accuracy of certain representations and warranties and the absence of any default or unmatured default. The new facility has a financial covenant requiring that OG&E maintain a maximum debt to capitalization ratio of 65 percent , as defined in the facility. OG&E's new facility also contains covenants which restrict, among other things, mergers and consolidations, sales of all or substantially all assets, incurrence of liens and transactions with affiliates. OG&E's new facility is subject to acceleration upon the occurrence of any default, including, among others, payment defaults on such facility, breach of representations, warranties and covenants, acceleration of indebtedness (other than intercompany and non-recourse indebtedness) of $100.0 million or more in the aggregate, change of control (as defined in the new facility), nonpayment of uninsured judgments in excess of $100.0 million and the occurrence of certain Employee Retirement Income Security Act and bankruptcy events, subject where applicable to specified cure periods. At December 31, 2017 , there were $112.5 million in advances to OGE Energy compared to $49.9 million in advances from OGE Energy at December 31, 2016 . OG&E has an intercompany borrowing agreement with OGE Energy whereby OG&E has access to up to $350.0 million of OGE Energy's revolving credit amount. This agreement has a termination date of March 8, 2022 . At December 31, 2017 , there were no intercompany borrowings under this agreement. At December 31, 2017 , there were $0.3 million supporting letters of credit at a weighted-average interest rate of 0.95 percent . There were no outstanding commercial paper borrowings at December 31, 2017 . OGE Energy's and OG&E's ability to access the commercial paper market could be adversely impacted by a credit ratings downgrade or major market disruptions. Pricing grids associated with OGE Energy's and OG&E's credit facilities could cause annual fees and borrowing rates to increase if an adverse rating impact occurs. The impact of any future downgrade could include an increase in the costs of OGE Energy's and OG&E's short-term borrowings, but a reduction in OGE Energy's and OG&E's credit rating s would not result in any defaults or accelerations. Any future downgrade of OGE Energy or OG&E could also lead to higher long-term borrowing costs and, if below investment grade, would require OG&E to post collateral or letters of credit. OG&E must obtain regulatory approval from the FERC in order to borrow on a short-term basis. OG&E has the necessary regulatory approvals to incur up to $800.0 million in short-term borrowings at any one time for a two-year period beginning January 1, 2017 and ending December 31, 2018. |
Retirement Plans and Postretire
Retirement Plans and Postretirement Benefit Plans | 12 Months Ended |
Dec. 31, 2017 | |
Defined Benefit Plan [Abstract] | |
Pension and Other Postretirement Benefits Disclosure [Text Block] | Retirement Plans and Postretirement Benefit Plans Pension Plan and Restoration of Retirement Income Plan OG&E's employees participate in OGE Energy's Pension Plan and Restoration of Retirement Income Plan. It is OGE Energy's policy to fund the Pension Plan on a current basis based on the net periodic pension expense as determined by OGE Energy's actuarial consultants. Such contributions are intended to provide not only for benefits attributed to service to date but also for those expected to be earned in the future. OGE Energy made a $20.0 million contribution to its Pension Plan in both 2017 and 2016 , of which $4.0 million is related to OG&E in 2017 compared to no contributions related to OG&E in 2016 . OGE Energy has not determined whether it will need to make any contributions to the Pension Plan in 2018 . Any contribution to the Pension Plan during 2018 would be a discretionary contribution, anticipated to be in the form of cash, and is not required to satisfy the minimum regulatory funding requirement specified by the Employee Retirement Income Security Act of 1974, as amended. OGE Energy could be required to make additional contributions if the value of its pension trust and postretirement benefit plan trust assets are adversely impacted by a major market disruption in the future. In accordance with ASC Topic 715, "Compensation - Retirement Benefits," a one-time settlement charge is required to be recorded by an organization when lump sum payments or other settlements that relieve the organization from the responsibility for the pension benefit obligation during a plan year exceed the service cost and interest cost components of the organization’s net periodic pension cost. During 2017 and 2015, OG&E experienced an increase in both the number of employees electing to retire and the amount of lump sum payments paid to such employees upon retirement. As a result, OG&E recorded pension settlement charges of $11.7 million in the fourth quarter of 2017 and $14.2 million during 2015, of which $10.8 million and $12.5 million , respectively, related to OG&E's Oklahoma jurisdiction and has been included in the Pension tracker. The pension settlement charges did not increase OG&E's total pension expense over time, as the charges were an acceleration of costs that otherwise would be recognized as pension expense in future periods. During the quarter ended June 30, 2016, OG&E experienced a settlement of its non-qualified Restoration of Retirement Income Plan. As a result, OG&E recorded pension settlement charges of $0.4 million during 2016, of which $0.4 million related to OG&E's Oklahoma jurisdiction and has been included in the Pension tracker. OGE Energy provides a Restoration of Retirement Income Plan to those participants in OGE Energy's Pension Plan whose benefits are subject to certain limitations of the Code. Participants in the Restoration of Retirement Income Plan receive the same benefits that they would have received under OGE Energy's Pension Plan in the absence of limitations imposed by the federal tax laws. The Restoration of Retirement Income Plan is intended to be an unfunded plan. Obligations and Funded Status The following table presents the status of OGE Energy's Pension Plan, the Restoration of Retirement Income Plan and the postretirement benefit plans for 2017 and 2016 . These amounts have been recorded in Accrued Benefit Obligations with the offset recorded as a regulatory asset in OG&E's Balance Sheets as discussed in Note 1. The regulatory asset represents a net periodic benefit cost to be recognized in the Statements of Income in future periods. OG&E's portion of the benefit obligation for OGE Energy's Pension Plan and the Restoration of Retirement Income Plan represents the projected benefit obligation, while the benefit obligation for the postretirement benefit plans represents the accumulated postretirement benefit obligation. The accumulated postretirement benefit obligation for OG&E's Pension Plan and Restoration of Retirement Income Plan differs from the projected benefit obligation in that the former includes no assumption about future compensation levels. The accumulated postretirement benefit obligation for the Pension Plan and the Restoration of Retirement Income Plan at December 31, 2017 was $469.0 million and $3.9 million , respectively. The accumulated postretirement benefit obligation for the Pension Plan and the Restoration of Retirement Income Plan at December 31, 2016 was $458.1 million and $3.4 million , respectively. The details of the funded status of the Pension Plan, the Restoration of Retirement Income Plan and the postretirement benefit plans and the amounts included in the Balance Sheets are as follows: Pension Plan Restoration of Retirement Postretirement December 31 (In millions) 2017 2016 2017 2016 2017 2016 Change in benefit obligation Beginning obligations $ 500.5 $ 514.4 $ 4.0 $ 2.7 $ 166.4 $ 176.1 Service cost 10.1 10.3 0.1 0.1 0.4 0.6 Interest cost 19.5 19.2 0.2 0.1 5.6 7.4 Plan settlements (35.2 ) — — (1.0 ) (21.1 ) — Plan amendments — — — — (29.4 ) — Participants' contributions — — — — 2.7 2.9 Actuarial losses (gains) 28.8 1.2 0.1 2.1 4.6 (7.2 ) Benefits paid (13.1 ) (44.6 ) (0.2 ) — (13.4 ) (13.4 ) Ending obligations $ 510.6 $ 500.5 $ 4.2 $ 4.0 $ 115.8 $ 166.4 Change in plans' assets Beginning fair value $ 457.3 $ 464.2 $ — $ — $ 47.8 $ 50.0 Actual return on plans' assets 64.2 37.7 — — 2.5 1.8 Employer contributions 4.0 — 0.2 1.0 26.7 6.5 Plan settlements (35.2 ) — — (1.0 ) (21.1 ) — Participants' contributions — — — — 2.7 2.9 Benefits paid (13.1 ) (44.6 ) (0.2 ) — (13.4 ) (13.4 ) Ending fair value $ 477.2 $ 457.3 $ — $ — $ 45.2 $ 47.8 Funded status at end of year $ (33.4 ) $ (43.2 ) $ (4.2 ) $ (4.0 ) $ (70.6 ) $ (118.6 ) Net Periodic Benefit Cost Pension Plan Restoration of Retirement Postretirement Benefit Plans Year Ended December 31 (In millions) 2017 2016 2015 2017 2016 2015 2017 2016 2015 Included in Other Operation and Maintenance: Service cost $ 10.1 $ 10.3 $ 10.3 $ 0.1 $ 0.1 $ 0.1 $ 0.4 $ 0.6 $ 1.0 Included in Other Net Periodic Pension and Postretirement (Cost) Benefit: Interest cost 19.5 19.2 19.8 0.2 0.1 0.1 5.6 7.4 7.9 Expected return on plan assets (32.8 ) (33.1 ) (36.5 ) — — — (2.0 ) (2.1 ) (2.2 ) Amortization of net loss 13.0 12.4 13.8 0.4 0.1 0.1 1.9 2.5 11.9 Amortization of unrecognized prior service cost (A) — — 0.5 — — — (2.5 ) (6.1 ) (13.6 ) Settlement 11.7 — 14.2 — 0.4 — 0.4 — — Net periodic benefit cost (B) $ 21.5 $ 8.8 $ 22.1 $ 0.7 $ 0.7 $ 0.3 $ 3.8 $ 2.3 $ 5.0 (A) Unamortized prior service cost is amortized on a straight-line basis over the average remaining service period to the first eligibility age of participants who are expected to receive a benefit and are active at the date of the plan amendment. (B) In addition to the $26.0 million , $11.8 million and $27.4 million of net periodic benefit cost recognized in 2017 , 2016 and 2015 , respectively, OG&E recognized the following: • a change in pension expense in 2017 , 2016 and 2015 of $(2.3) million , $9.9 million and $(3.1) million , respectively, to maintain the allowable amount to be recovered for pension expense in the Oklahoma jurisdiction, which are included in the Pension tracker regulatory asset or liability (see Note 1); • an increase in postretirement medical expense in 2017 , 2016 and 2015 of $6.2 million , $7.9 million and $5.8 million , respectively, to maintain the allowable amount to be recovered for postretirement medical expense in the Oklahoma jurisdiction which are included in the Pension tracker regulatory asset or liability (see Note 1); and • a deferral of pension expense in 2017, 2016 and 2015 of $0.9 million , $0.1 million and $1.9 million related to the Arkansas jurisdictional portion of the pension settlement charge of $11.7 million , $0.4 million and $14.2 million , respectively. (In millions) 2017 2016 2015 Capitalized portion of net periodic pension benefit cost $ 3.4 $ 2.9 $ 2.6 Capitalized portion of net periodic postretirement benefit cost 1.1 0.8 1.6 Rate Assumptions Pension Plan and Postretirement Year Ended December 31 2017 2016 2015 2017 2016 2015 Discount rate 3.60 % 4.00 % 4.00 % 3.70 % 4.20 % 4.25 % Rate of return on plans' assets 7.50 % 7.50 % 7.50 % 4.00 % 4.00 % 4.00 % Compensation increases 4.20 % 4.20 % 4.20 % N/A N/A N/A Assumed health care cost trend: Initial trend N/A N/A N/A 7.50 % 6.75 % 6.10 % Ultimate trend rate N/A N/A N/A 4.50 % 4.50 % 4.50 % Ultimate trend year N/A N/A N/A 2030 2026 2026 N/A - not applicable The discount rate used to compute the present value of plan liabilities is based generally on rates of high-grade corporate bonds with maturities similar to the average period over which benefits will be paid. The discount rate used to determine net benefit cost for the current year is the same discount rate used to determine the benefit obligation as of the previous year's balance sheet date. The overall expected rate of return on plan assets assumption was 7.50 percent in both 2017 and 2016 , which was used in determining net periodic benefit cost due to recent returns on OGE Energy's long-term investment portfolio. The rate of return on plan assets assumption is the average long-term rate of earnings expected on the funds currently invested and to be invested for the purpose of providing benefits specified by the Pension Plan or postretirement benefit plans. This assumption is reexamined at least annually and updated as necessary. The rate of return on plan assets assumption reflects a combination of historical return analysis, forward-looking return expectations and the plans' current and expected asset allocation. The assumed health care cost trend rates have a significant effect on the amounts reported for postretirement medical benefit plans. Future health care cost trend rates are assumed to be 6.50 percent in 2018 with the rates trending downward to 4.50 percent by 2026 . A one-percentage point change in the assumed health care cost trend rate would have the following effects: ONE-PERCENTAGE POINT INCREASE Year Ended December 31 (In millions) 2017 2016 2015 Effect on aggregate of the service and interest cost components $ — $ — $ — Effect on accumulated postretirement benefit obligations 0.1 0.1 0.1 ONE-PERCENTAGE POINT DECREASE Year Ended December 31 (In millions) 2017 2016 2015 Effect on aggregate of the service and interest cost components $ — $ — $ — Effect on accumulated postretirement benefit obligations 0.2 0.5 0.5 Pension Plan Investments, Policies and Strategies The Pension Plan assets are held in a trust which follows an investment policy and strategy designed to reduce the funded status volatility of the Plan by utilizing liability driven investing. The purpose of liability-driven investing is to structure the asset portfolio to more closely resemble the pension liability and thereby more effectively hedge against changes in the liability. The investment policy follows a glide path approach that shifts a higher portfolio weighting to fixed income as the Plan's funded status increases. The table below sets forth the targeted fixed income and equity allocations at different funded status levels. Projected Benefit Obligation Funded Status Thresholds <90% 95% 100% 105% 110% 115% 120% Fixed income 50% 58% 65% 73% 80% 85% 90% Equity 50% 42% 35% 27% 20% 15% 10% Total 100% 100% 100% 100% 100% 100% 100% Within the portfolio's overall allocation to equities, the funds are allocated according to the guidelines in the table below. Asset Class Target Allocation Minimum Maximum Domestic Large Cap Equity 40% 35% 60% Domestic Mid-Cap Equity 15% 5% 25% Domestic Small-Cap Equity 25% 5% 30% International Equity 20% 10% 30% OGE Energy has retained an investment consultant responsible for the general investment oversight, analysis, monitoring investment guideline compliance and providing quarterly reports to certain of OG&E's members and OGE Energy's Investment Committee. The various investment managers used by the trust operate within the general operating objectives as established in the investment policy and within the specific guidelines established for each investment manager's respective portfolio. The portfolio is rebalanced at least on an annual basis to bring the asset allocations of various managers in line with the target asset allocation listed above. More frequent rebalancing may occur if there are dramatic price movements in the financial markets which may cause the trust's exposure to any asset class to exceed or fall below the established allowable guidelines. To evaluate the progress of the portfolio, investment performance is reviewed quarterly. It is, however, expected that performance goals will be met over a full market cycle, normally defined as a three to five year period. Analysis of performance is within the context of the prevailing investment environment and the advisors' investment style. The goal of the trust is to provide a rate of return consistently from three percent to five percent over the rate of inflation (as measured by the national Consumer Price Index) on a fee adjusted basis over a typical market cycle of no less than three years and no more than five years. Each investment manager is expected to outperform its respective benchmark. Below is a list of each asset class utilized with appropriate comparative benchmark(s) each manager is evaluated against: Asset Class Comparative Benchmark(s) Active Duration Fixed Income Bloomberg Barclays Aggregate Long Duration Fixed Income Duration blended Barclays Long Government/Credit & Barclays Universal Equity Index Standard & Poor's 500 Index Mid-Cap Equity Russell Midcap Index Russell Midcap Value Index Small-Cap Equity Russell 2000 Index Russell 2000 Value Index International Equity Morgan Stanley Capital Investment ACWI ex-U.S. The fixed income managers are expected to use discretion over the asset mix of the trust assets in its efforts to maximize risk-adjusted performance. Exposure to any single issuer, other than the U.S. government, its agencies or its instrumentalities (which have no limits), is limited to five percent of the fixed income portfolio as measured by market value. At least 75 percent of the invested assets must possess an investment-grade rating at or above Baa3 or BBB- by Moody's Investors Services, Standard & Poor's Ratings Services or Fitch Ratings. The portfolio may invest up to 10 percent of the portfolio's market value in convertible bonds as long as the securities purchased meet the quality guidelines. A portfolio may invest up to 15 percent of the portfolio's market value in private placement, including 144A securities with or without registration rights and allow for futures to be traded in the portfolio. The purchase of any of OGE Energy's equity, debt or other securities is prohibited. The domestic value equity managers focus on stocks that the manager believes are undervalued in price and earn an average or less than average return on assets and often pays out higher than average dividend payments. The domestic growth equity manager will invest primarily in growth companies which consistently experience above average growth in earnings and sales, earn a high return on assets and reinvest cash flow into existing business. The domestic mid-cap equity portfolio manager focuses on companies with market capitalizations lower than the average company traded on the public exchanges with the following characteristics: price/earnings ratio at or near the Russell Midcap Index, small dividend yield, return on equity at or near the Russell Midcap Index and an earnings per share growth rate at or near the Russell Midcap Index. The domestic small-cap equity manager will purchase shares of companies with market capitalizations lower than the average company traded on the public exchanges with the following characteristics: price/earnings ratio at or near the Russell 2000, small dividend yield, return on equity at or near the Russell 2000 and an earnings per share growth rate at or near the Russell 2000. The international global equity manager invests primarily in non-dollar denominated equity securities. Investing internationally diversifies the overall trust across the global equity markets. The manager is required to operate under certain restrictions including regional constraints, diversification requirements and percentage of U.S. securities. The Morgan Stanley Capital International All Country World ex-U.S. Index is the benchmark for comparative performance purposes. The Morgan Stanley Capital International All Country World ex-U.S. Index is a market value weighted index designed to measure the combined equity market performance of developed and emerging markets countries, excluding the U.S. All of the equities which are purchased for the international portfolio are thoroughly researched. All securities are freely traded on a recognized stock exchange, and there are no over-the-counter derivatives. The following investment categories are excluded: options (other than traded currency options), commodities, futures (other than currency futures or currency hedging), short sales/margin purchases, private placements, unlisted securities and real estate (but not real estate shares). For all domestic equity investment managers, no more than five percent can be invested in any one stock at the time of purchase and no more than 10 percent after accounting for price appreciation. Options or financial futures may not be purchased unless prior approval of OGE Energy's Investment Committee is received. The purchase of securities on margin is prohibited as is securities lending. Private placement or venture capital may not be purchased. All interest and dividend payments must be swept on a daily basis into a short-term money market fund for re-deployment. The purchase of any of OGE Energy's equity, debt or other securities is prohibited. The purchase of equity or debt issues of the portfolio manager's organization is also prohibited. The aggregate positions in any company may not exceed one percent of the fair market value of its outstanding stock. Pension Plan Investments The following tables summarize OG&E's portion of OGE Energy's Pension Plan's investments that are measured at fair value on a recurring basis at December 31, 2017 and 2016 . There were no Level 3 investments held by the Pension Plan at December 31, 2017 and 2016 . (In millions) December 31, 2017 Level 1 Level 2 Net Asset Value (A) Common stocks $ 225.9 $ 225.9 $ — $ — U.S. Treasury notes and bonds (B) 169.7 169.7 — — Mortgage- and asset-backed securities 43.4 — 43.4 — Corporate fixed income and other securities 153.8 — 153.8 — Commingled fund (C) 29.9 — — 29.9 Foreign government bonds 4.0 — 4.0 — U.S. municipal bonds 1.2 — 1.2 — Money market fund 4.3 — — 4.3 Mutual fund 7.8 7.8 — — Futures: U.S. Treasury futures (receivable) 13.4 — 13.4 — U.S. Treasury futures (payable) (11.4 ) — (11.4 ) — Cash collateral 0.3 0.3 — — Forward contracts: Receivable (foreign currency) 0.1 — 0.1 — Total Pension Plan investments $ 642.4 $ 403.7 $ 204.5 $ 34.2 Receivable from broker for securities sold — Interest and dividends receivable 3.2 Payable to broker for securities purchased (10.3 ) Pension Plan investments attributable to affiliates (158.1 ) Total Pension Plan assets $ 477.2 (In millions) December 31, 2016 Level 1 Level 2 Net Asset Value (A) Common stocks $ 237.1 $ 237.1 $ — $ — U.S. Treasury notes and bonds (B) 122.3 122.3 — — Mortgage-backed securities 59.2 — 59.2 — Corporate fixed income and other securities 137.6 — 137.6 — Commingled fund (C) 23.8 — — 23.8 Foreign government bonds 5.2 — 5.2 — U.S. municipal bonds 1.9 — 1.9 — Money market fund 2.2 — — 2.2 Mutual fund 9.0 9.0 — — Futures: U.S. Treasury futures (receivable) 10.7 — 10.7 — U.S. Treasury futures (payable) (2.3 ) — (2.3 ) — Cash collateral 0.3 0.3 — — Forward contracts: Receivable (foreign currency) 0.2 — 0.2 — Total Pension Plan investments $ 607.2 $ 368.7 $ 212.5 $ 26.0 Receivable from broker for securities sold — Interest and dividends receivable 3.0 Payable to broker for securities purchased (14.3 ) Pension Plan investments attributable to affiliates (138.6 ) Total Pension Plan assets $ 457.3 (A) GAAP allows the measurement of certain investments that do not have a readily determinable fair value at the net asset value. These investments do not consider the observability of inputs; therefore, they are not included within the fair value hierarchy. (B) This category represents U.S. Treasury notes and bonds with a Moody's Investors Services rating of Aaa and Government Agency Bonds with a Moody's Investors Services rating of A1 or higher. (C) This category represents units of participation in a commingled fund that primarily invested in stocks of international companies and emerging markets. The three levels defined in the fair value hierarchy and examples of each are as follows: Level 1 inputs are quoted prices in active markets for identical unrestricted assets or liabilities that are accessible by the Pension Plan at the measurement date. Instruments classified as Level 1 include investments in common stocks, U.S. Treasury notes and bonds, mutual funds and cash collateral. Level 2 inputs are inputs other than quoted prices in active markets included within Level 1 that are either directly or indirectly observable at the reporting date for the asset or liability for substantially the full term of the asset or liability. Level 2 inputs include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Instruments classified as Level 2 include corporate fixed income and other securities, mortgage- and asset-backed securities, U.S. municipal bonds, foreign government bonds, U.S. Treasury futures contracts and forward contracts. Level 3 inputs are prices or valuation techniques for the asset or liability that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). Unobservable inputs reflect the Plan's own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). Postretirement Benefit Plans In addition to providing pension benefits, OGE Energy provides certain medical and life insurance benefits for eligible retired members. Regular, full-time, active employees hired prior to February 1, 2000 whose age and years of credited service total or exceed 80 or have attained at least age 55 with 10 or more years of service at the time of retirement are entitled to postretirement medical benefits, while employees hired on or after February 1, 2000 are not entitled to postretirement medical benefits. Eligible retirees must contribute such amount as OGE Energy specifies from time to time toward the cost of coverage for postretirement benefits. The benefits are subject to deductibles, co-payment provisions and other limitations. OG&E charges postretirement benefit costs to expense and includes an annual amount as a component of the cost-of-service in future ratemaking proceedings. OGE Energy's contribution to the medical costs for pre-65 aged eligible retirees are fixed at the 2011 level, and OGE Energy covers future annual medical inflationary cost increases up to five percent . Increases in excess of five percent annually are covered by the pre-65 aged retiree in the form of premium increases. OGE Energy provides Medicare-eligible retirees and their Medicare-eligible spouses an annual fixed contribution to OGE Energy's sponsored health reimbursement arrangement. OGE Energy's Medicare-eligible retirees are able to purchase individual insurance policies supplemental to Medicare through a third-party administrator and use their health reimbursement arrangement funds for reimbursement of medical premiums and other eligible medical expenses. In August 2017, OGE Energy adopted an amendment to the retiree medical plan. Effective January 1, 2018, OGE Energy will reduce the amount of supplemental Medicare coverage for Medicare-eligible retirees, providing a fixed stipend based on current market analysis in August 2017. OGE Energy will continue to allow those Medicare-eligible retirees to acquire coverage from a company-provided third-party administrator. The effect of these plan amendments is reflected in the OGE Energy’s December 31, 2017 Consolidated Balance Sheet as a reduction to the postretirement benefit obligation of $42.9 million . In August 2017, OGE Energy settled the retiree life plan in its entirety and paid $26.4 million to participants in August 2017. No gain or loss was recognized upon settlement, and the effect of the settlement is reflected in OGE Energy's December 31, 2017 Consolidated Balance Sheet as a reduction in the Accrued Benefit Obligations of $27.9 million and related other comprehensive income and regulatory asset of $2.1 million . Postretirement Plans Investments The following tables summarize OG&E's portion of OGE Energy's postretirement benefit plans' investments that are measured at fair value on a recurring basis at December 31, 2017 and 2016 . There were no Level 2 investments held by the postretirement benefit plans at December 31, 2017 and 2016 . (In millions) December 31, 2017 Level 1 Level 3 Group retiree medical insurance contract $ 40.2 $ — $ 40.2 Mutual funds investment: U.S. equity investments 9.5 9.5 — Cash 0.5 0.5 — Total plan investments $ 50.2 $ 10.0 $ 40.2 Plan investments attributable to affiliates (5.0 ) Total plan assets $ 45.2 (In millions) December 31, 2016 Level 1 Level 3 Group retiree medical insurance contract $ 44.7 $ — $ 44.7 Mutual funds investment: U.S. equity investments 8.1 8.1 — Money market funds investment 0.3 0.3 — Total plan investments $ 53.1 $ 8.4 $ 44.7 Plan investments attributable to affiliates (5.3 ) Total plan assets $ 47.8 The group retiree medical insurance contract invests in a pool of common stocks, bonds and money market accounts, of which a significant portion is comprised of mortgage-backed securities. The unobservable input included in the valuation of the contract includes the approach for determining the allocation of the postretirement benefit plans' pro-rata share of the total assets in the contract. The following table summarizes the postretirement benefit plans' investments that are measured at fair value on a recurring basis using significant unobservable inputs (Level 3). Year Ended December 31 (In millions) 2017 Group retiree medical insurance contract: Beginning balance $ 44.7 Interest income 0.8 Dividend income 0.5 Net unrealized gains related to instruments held at the reporting date 0.3 Claims paid (5.9 ) Realized losses (0.1 ) Investment fees (0.1 ) Ending balance $ 40.2 Medicare Prescription Drug, Improvement and Modernization Act of 2003 The Medicare Prescription Drug, Improvement and Modernization Act of 2003 expanded coverage for prescription drugs. The following table summarizes the gross benefit payments OG&E expects to pay related to its postretirement benefit plans, including prescription drug benefits . (In millions) Gross Projected 2018 $ 9.3 2019 9.3 2020 9.4 2021 9.3 2022 9.3 After 2022 37.5 The following table summarizes the benefit payments OG&E expects to pay related to OGE Energy's Pension Plan and Restoration of Retirement Income Plan. These expected benefits are based on the same assumptions used to measure OGE Energy's benefit obligation at the end of the year and include benefits attributable to estimated future employee service. (In millions) Projected Benefit Payments 2018 $ 46.9 2019 47.3 2020 48.2 2021 46.7 2022 44.6 After 2022 206.4 Post-Employment Benefit Plan Disabled employees receiving benefits from OGE Energy's Group Long-Term Disability Plan are entitled to continue participating in OGE Energy's Medical Plan along with their dependents. The post-employment benefit obligation represents the actuarial present value of estimated future medical benefits that are attributed to employee service rendered prior to the date as of which such information is presented. The obligation also includes future medical benefits expected to be paid to current employees participating in OGE Energy's Group Long-Term Disability Plan and their dependents, as defined in OGE Energy's Medical Plan. The post-employment benefit obligation is determined by an actuary on a basis similar to the accumulated postretirement benefit obligation. The estimated future medical benefits are projected to grow with expected future medical cost trend rates and are discounted for interest at the discount rate and for the probability that the participant will discontinue receiving benefits from OGE Energy's Group Long-Term Disability Plan due to death, recovery from disability or eligibility for retiree medical benefits. OG&E's post-employment benefit obligation was $2.2 million and $2.1 million at December 31, 2017 and 2016 , respectively. 401(k) Plan OGE Energy provides a 401(k) Plan, and each regular full-time employee of OGE Energy or a participating affiliate is eligible to participate in the 401(k) Plan immediately. All other employees of OGE Energy or a participating affiliate are eligible to become participants in the 401(k) Plan after completing one year of service as defined in the 401(k) Plan. Participants may contribute each pay period any whole percentage between two percent and 19 percent of their compensation, as defined in the 401(k) Plan, for that pay period. Participants who have reached age 50 before the close of a year are allowed to make additional contributions referred to as "Catch-Up Contributions," subject to certain limitations of the Code. Participants may designate, at their discretion, all or any portion of their contributions as: (i) a before-tax contribution under Section 401(k) of the Code subject to the limitations thereof, (ii) a contribution made on a non-Roth after-tax basis or (iii) a Roth contribution. The 401(k) Plan also includes an eligible automatic contribution arrangement and provides for a qualified default investment alternative consistent with the U.S. Department of Labor regulations. Participants may elect, in accordance with the 401(k) Plan procedures, to have his or her future salary deferral rate to be automatically increased annually on a date and in an amount as specified by the participant in such election. For employees hired or rehired on or after December 1, 2009, OGE Energy contributes to the 401(k) Plan, on behalf of each participant, 200 percent of the participant's contributions up to five percent of compensation. No OGE Energy contributions are made with respect to a participant's Catch-Up Contributions, rollover contributions or with respect to a participant's contributions based on overtime payments, pay-in-lieu of overtime for exempt personnel, special lump-sum recognition awards and lump-sum merit awards included in compensation for determining the amount of participant contributions. Once made, OGE Energy's contribution may be directed to any available investment option in the 401(k) Plan. OGE Energy match contributions vest over a three -year period. After two years of service, participants become 20 percent vested in their OGE Energy contribution account and become fully vested on completing three years of service. In addition, participants fully vest when they are eligible for normal or early retirement under the Pension Plan requirements, in the event of their termination due to death or permanent disability or upon attainment of age 65 while employed by OGE Energy or its affiliates. OG&E contributed $9.7 million , $8.8 million and $8.2 million in 2017 , 2016 and 2015 , respectively, to the 401(k) Plan. Deferred Compensation Plan OGE Energy provides a nonqualified deferred compensation plan which is intended to be an unfunded plan. The plan's primary purpose is to provide a tax-deferred capital accumulation vehicle for a select group of management, highly compensated employees and non-employee members of the Board of Directors of OGE Energy and to supplement such employees' 401(k) Plan contributions as well as offering this plan to be competitive in the marketplace. Eligible employees who enroll in the plan have the following deferral options: (i) eligible employees may elect to defer up to a maximum of 70 percent of base salary and 100 percent of annual bonus awards or (ii) eligible employees may elect a deferral percentage of base salary and bonus awards based on the deferral percentage elected for a year under the 401(k) Plan with such |
Commitments and Contingencies
Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2017 | |
Commitments and Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | Commitments and Contingencies Operating Lease Obligations OG&E has operating lease obligations expiring at various dates , primarily for railcar leases and wind farm land leases . Future minimum payments for noncancellable operating leases are as follows: Year Ended December 31 (In millions) 2018 2019 2020 2021 2022 After 2022 Total Operating lease obligations: Railcars $ 1.7 $ 20.9 $ — $ — $ — $ — $ 22.6 Wind farm land leases 2.5 2.5 2.9 2.9 2.9 40.6 54.3 Total operating lease obligations $ 4.2 $ 23.4 $ 2.9 $ 2.9 $ 2.9 $ 40.6 $ 76.9 Payments for operating lease obligations were $5.4 million , $8.5 million and $6.9 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. Railcar Lease Agreement OG&E has a noncancellable operating lease with a purchase option, covering 1,243 rotary gondola railcars to transport coal from Wyoming to OG&E's coal-fired generation units. Rental payments are charged to fuel expense and are recovered through OG&E's tariffs and fuel adjustment clauses. On December 17, 2015, OG&E renewed the lease agreement effective February 1, 2016. At the end of the new lease term, which is February 1, 2019, OG&E has the option to either purchase the railcars at a stipulated fair market value or renew the lease. If OG&E chooses not to purchase the railcars or renew the lease agreement and the actual fair value of the railcars is less than the stipulated fair market value, OG&E would be responsible for the difference in those values up to a maximum of $18.2 million . OG&E is also required to maintain all of the railcars it has under the operating lease. Wind Farm Land Lease Agreements OG&E has operating leases related to land for its Centennial, OU Spirit and Crossroads wind farms expiring at various dates. The Centennial lease has rent escalations which increase annually based on the Consumer Price Index. The OU Spirit and Crossroads leases have rent escalations which increase after five and 10 years. Although the leases are cancellable, OG&E is required to make annual lease payments as long as the wind turbines are located on the land. OG&E does not expect to terminate the leases until the wind turbines reach the end of their useful life. Other Purchase Obligations and Commitments OG&E's other future purchase obligations and commitments estimated for the next five years are as follows: (In millions) 2018 2019 2020 2021 2022 Total Other purchase obligations and commitments: Cogeneration capacity and fixed operation and maintenance payments $ 72.8 $ 65.3 $ 53.2 $ 49.5 $ 45.4 $ 286.2 Expected cogeneration energy payments 35.7 35.6 35.9 37.1 38.3 182.6 Minimum fuel purchase commitments 139.8 36.2 24.6 24.6 24.6 249.8 Expected wind purchase commitments 58.7 56.5 56.9 57.3 57.8 287.2 Long-term service agreement commitments 7.9 41.9 2.4 2.4 2.4 57.0 Mustang Modernization expenditures 24.9 — — — — 24.9 Environmental compliance plan expenditures 63.0 8.9 0.2 — — 72.1 Total other purchase obligations and commitments $ 402.8 $ 244.4 $ 173.2 $ 170.9 $ 168.5 $ 1,159.8 Public Utility Regulatory Policy Act of 1978 At December 31, 2017 , OG&E has a QF contract with Oklahoma Cogeneration LLC which expires on August 31, 2019, and a QF contract with AES-Shady Point, Inc. which expires on January 15, 2023. These contracts were entered into pursuant to the Public Utility Regulatory Policy Act of 1978. Stated generally, the Public Utility Regulatory Policy Act of 1978 and the regulations thereunder promulgated by the FERC require OG&E to purchase power generated in a manufacturing process from a QF. The rate for such power to be paid by OG&E was approved by the OCC. The rate generally consists of two components: one is a rate for actual electricity purchased from the QF by OG&E, and the other is a capacity charge, which OG&E must pay the QF for having the capacity available. However, if no electrical power is made available to OG&E for a period of time (generally three months), OG&E's obligation to pay the capacity charge is suspended. The total cost of cogeneration payments is recoverable in rates from customers. For the 320 MWs AES-Shady Point, Inc. QF contract and the 120 MWs Oklahoma Cogeneration LLC QF contract, OG&E purchases 100 percent of the electricity generated by the QFs. As part of the QF contract with AES-Shady Point Inc., OG&E had the option beginning in July 2017 to provide notice to AES-Shady Point Inc. to terminate the contract in January 2018. On July 17, 2017, OG&E and AES-Shady Point, Inc. amended the agreement to allow OG&E the ability, through July 17, 2018, to provide AES-Shady Point Inc. a termination notice that would terminate the agreement on January 15, 2019. For the years ended December 31, 2017 , 2016 and 2015 , OG&E made total payments to cogenerators of $115.2 million , $124.8 million and $124.0 million , respectively, of which $63.0 million , $66.3 million and $69.5 million , respectively, represented capacity payments. All payments for purchased power, including cogeneration, are included in the Statements of Income as Cost of Sales. Minimum Fuel Purchase Commitments OG&E has coal contracts for purchases through June 2018. As a participant in the SPP Integrated Marketplace, OG&E now purchases a relatively small percentage of its natural gas supply through long-term agreements. Alternatively, OG&E relies on a combination of natural gas call agreements, whereby OG&E has the right but not the obligation to purchase a defined quantity of natural gas, combined with day and intra-day purchases to meet the demands of the SPP Integrated Marketplace. Wind Purchase Commitments OG&E owns the 120 MW Centennial, 101 MW OU Spirit and 228 MW Crossroads wind farms. OG&E's current wind power portfolio also includes purchase power contracts with the following: Company Location Term of Contract Expiration of Contract MWs CPV Keenan Woodward County, OK 20 years 2030 152.0 Edison Mission Energy Dewey County, OK 20 years 2031 130.0 NextEra Energy Blackwell, OK 20 years 2032 60.0 FPL Energy Woodward, OK 15 years 2018 50.0 The following table summarizes OG&E's wind power purchases for the years ended December 31, 2017 , 2016 and 2015 . Year Ended December 31 (In millions) 2017 2016 2015 CPV Keenan $ 29.0 $ 29.2 $ 26.7 Edison Mission Energy 22.1 21.1 19.7 NextEra Energy 7.4 7.3 7.0 FPL Energy 2.6 3.4 3.2 Total wind power purchased $ 61.1 $ 61.0 $ 56.6 Long-Term Service Agreement Commitments OG&E has a long-term parts and service maintenance contract for the upkeep of the McClain Plant. In May 2013, a new contract was signed that is expected to run for the earlier of 128,000 factored-fired hours or 4,800 factored-fired starts. On December 30, 2015, the McClain Long-Term Service Agreement was amended to define the terms and conditions for the exchange of spare rotors between OG&E and General Electric International, Inc. Based on historical usage and current expectations for future usage, this contract is expected to run until 2031. The contract requires payments based on both a fixed and variable cost component, depending on how much the McClain Plant is used. OG&E has a long-term parts and service maintenance contract for the upkeep of the Redbud Plant. In March 2013, the contract was amended to extend the contract coverage for an additional 24,000 factored-fired hours resulting in a maximum of the earlier of 144,000 factored-fired hours or 4,500 factored-fired starts. Based on historical usage and current expectations for future usage, this contract is expected to run until 2029. The contract requires payments based on both a fixed and variable cost component, depending on how much the Redbud Plant is used. Enable Gas Transportation Agreement OG&E contracts with Enable for firm non-notice load following gas transportation services under a five year contract. The contract will expire in April 2019. In 2016, OG&E entered into an additional gas transportation services contract with Enable which will be effective upon the conversion of units 4 and 5 at Muskogee from coal to gas. Environmental Laws and Regulations The activities of OG&E are subject to numerous stringent and complex federal, state and local laws and regulations governing environmental protection. These laws and regulations can change, restrict or otherwise impact OG&E's business activities in many ways, including the handling or disposal of waste material, planning for future construction activities to avoid or mitigate harm to threatened or endangered species and requiring the installation and operation of emissions control equipment. Failure to comply with these laws and regulations could result in the assessment of administrative, civil and criminal penalties, the imposition of remedial requirements and the issuance of orders enjoining future operations. Management believes that all of its operations are in substantial compliance with current federal, state and local environmental standards. Environmental regulation can increase the cost of planning, design, initial installation and operation of OG&E's facilities. OG&E is managing several potentially material uncertainties about the scope and timing for the acquisition, installation and operation of additional pollution control equipment and compliance costs for a variety of the EPA rules that are being challenged in court. OG&E is unable to predict the financial impact of these matters with certainty at this time. Management continues to evaluate its compliance with existing and proposed environmental legislation and regulations and implement appropriate environmental programs in a competitive market. Air Quality Control System On September 10, 2014, OG&E executed a contract for the design, engineering and fabrication of two circulating Dry Scrubber systems to be installed at Sooner Units 1 and 2. OG&E entered into an agreement on February 9, 2015 to install the Dry Scrubber systems. The Dry Scrubbers are expected to be completed in mid to late 2018. More detail regarding the ECP can be found under the "Pending Regulatory Matters" in Note 13. Clean Power Plan On October 23, 2015, the EPA published the final Clean Power Plan that established standards of performance for CO 2 emissions from existing fossil-fuel-fired power plants along with state-specific CO 2 reduction standards expressed as both rate-based (lbs./MWh) and mass-based (tons/yr.) goals. However, the rule was challenged in court when it was issued, and the U.S. Supreme Court issued orders staying implementation of the Clean Power Plan on February 9, 2016 pending resolution of the court challenges. The EPA published a proposal on October 16, 2017 to repeal the Clean Power Plan. In addition, the EPA published an Advance Notice of Proposed Rulemaking seeking comments on regulatory options for replacing the Clean Power Plan. The ultimate timing and impact of these standards on OG&E's operations cannot be determined with certainty at this time, although a requirement for significant reduction of CO 2 emissions from existing fossil-fuel-fired power plants ultimately could result in significant additional compliance costs that would affect OG&E's future financial position, results of operations and cash flows if such costs are not recovered through regulated rates. Other In the normal course of business, OG&E is confronted with issues or events that may result in a contingent liability. These generally relate to lawsuits or claims made by third parties, including governmental agencies. When appropriate, management consults with legal counsel and other experts to assess the claim. If, in management's opinion, OG&E has incurred a probable loss as set forth by GAAP, an estimate is made of the loss, and the appropriate accounting entries are reflected in OG&E's Financial Statements. At the present time, based on current available information, OG&E believes that any reasonably possible losses in excess of accrued amounts arising out of pending or threatened lawsuits or claims would not be quantitatively material to its financial statements and would not have a material adverse effect on OG&E's financial position, results of operations or cash flows. |
Rate Matters and Regulation
Rate Matters and Regulation | 12 Months Ended |
Dec. 31, 2017 | |
Regulated Operations [Abstract] | |
Rate Matters and Regulation | Rate Matters and Regulation Regulation and Rates OG&E's retail electric tariffs are regulated by the OCC in Oklahoma and by the APSC in Arkansas. The issuance of certain securities by OG&E is also regulated by the OCC and the APSC. OG&E's transmission activities, short-term borrowing authorization and accounting practices are subject to the jurisdiction of the FERC. The Secretary of the U.S. Department of Energy has jurisdiction over some of OG&E's facilities and operations. In 2017 , 85 percent of OG&E's electric revenue was subject to the jurisdiction of the OCC, eight percent to the APSC and seven percent to the FERC. The OCC issued an order in 1996 authorizing OG&E to reorganize into a subsidiary of OGE Energy. The order required that, among other things, (i) OGE Energy permit the OCC access to the books and records of OGE Energy and its affiliates relating to transactions with OG&E, (ii) OGE Energy employ accounting and other procedures and controls to protect against subsidization of non-utility activities by OG&E's customers and (iii) OGE Energy refrain from pledging OG&E assets or income for affiliate transactions. In addition, the Energy Policy Act of 2005 enacted the Public Utility Holding Company Act of 2005, which in turn granted to the FERC access to the books and records of OGE Energy and its affiliates as the FERC deems relevant to costs incurred by OG&E or necessary or appropriate for the protection of utility customers with respect to the FERC jurisdictional rates . Completed Regulatory Matters Arkansas Rate Case Filing On August 25, 2016, OG&E filed a general rate case with the APSC. The rate filing requested a $16.5 million rate increase based on a 10.25 percent return on equity. The requested rate increase was based on a June 30, 2016 test year and included recovery of over $3.0 billion of electric infrastructure additions since the last Arkansas general rate case in 2011. The requested increase also reflected increases in operation and maintenance expenses, including vegetation management and increased recovery of depreciation and dismantlement costs. In May 2017, the APSC approved a settlement between OG&E and the staff of the APSC and other intervenors. The settlement provided for a $7.1 million annual rate increase and a 9.5 percent return on equity on a 50.0 percent equity capital structure. The settlement also provided that OG&E will be regulated under a formula rate rider, which should result in a more efficient process as the return on equity, depreciation rates and capital structure should not change from what was approved by the APSC in this settlement. The formula rate rider provides for an adjustment to rates if the earned rate of return falls outside of a plus or minus 50 basis point dead-band around the allowed return on equity. Adjustments are limited to plus or minus four percent of revenue for each rate class for the 12 months preceding the projected year. The initial term for the formula rate rider is not to exceed five years, unless additional approval is obtained from the APSC. OG&E expects to make its first filing under the Arkansas Formula Rate Rider in October 2018. Fuel Adjustment Clause Review for Calendar Year 2015 On September 8, 2016, the OCC staff filed an application to review OG&E’s fuel adjustment clause for calendar year 2015, including the prudence of OG&E’s electric generation, purchased power and fuel procurement costs. On October 12, 2017, the OCC issued an order finding that, for the calendar year 2015, OG&E's electric generation, purchased power and fuel procurement processes and costs were prudent. Oklahoma Rate Case Filing - 2015 On December 18, 2015, OG&E filed a general rate case with the OCC requesting a rate increase of $92.5 million and a 10.25 percent return on equity based on a common equity percentage of 53.0 percent . T he rate case was based on a June 30, 2015 test year and included recovery of $1.6 billion of electric infrastructure additions since its last general rate case in Oklahoma. On July 1, 2016, OG&E implemented an annual interim rate increase of $69.5 million , subject to refund for amounts in excess of the rates approved by the OCC. In December 2016, the ALJ issued a report and recommendations in the case. The ALJ's recommendations included, among other things, the use of OG&E's actual capital structure of 53.0 percent equity and 47.0 percent long-term debt and a return on equity of 9.87 percent resulting in an annual increase in OG&E's revenues of $40.7 million . During February and March 2017, the OCC held hearings and, on March 20, 2017, issued an order. The order resulted in an annual net increase of approximately $8.8 million in OG&E's rates to its Oklahoma retail customers. Although the order adopted certain recommendations set forth in the ALJ report, it differed in certain key respects. The primary adjustments to the ALJ report consist of: (i) Oklahoma retail authorized rate of return on equity of 9.50 percent , (ii) depreciation expense is reduced by approximately $28.6 million from the ALJ report or $36.4 million from then current rates on an annual basis, (iii) recovery of 50.0 percent of short-term incentive compensation and no recovery of long-term incentive compensation, (iv) recovery of OG&E's requested vegetation management expenses and (v) recovery of production tax credits expiring in 2017 and air quality control systems consumable costs through the fuel adjustment clause. The order maintained OG&E's existing capital structure of 53.0 percent equity and 47.0 percent long-term debt. As a result of the March 2017 OCC rate order, OG&E recorded, in the first quarter of 2017, adjustments to depreciation expense, amortization of regulatory assets and liabilities and impacts to the fuel adjustment clause effective July 1, 2016. On May 1, 2017, OG&E implemented new rates and began refunding excess amounts that it had collected in interim rates. As of November 30, 2017 , OG&E had completed the refund of $47.5 million collected in excess interim rates. Mustang Modernization Plan - Arkansas On August 15, 2017, OG&E filed for a determination with the APSC that the Mustang facility is in the public interest. The filing did not seek recovery for any costs associated with the Mustang Modernization Plan, as request for recovery of costs will take place with the first formula rate filing expected to be made in October 2018. On January 2, 2018, the APSC issued an order finding the Mustang Modernization Plan to be in the public interest. Pending Regulatory Matters Set forth below is a list of various proceedings pending before state or federal regulatory agencies. Unless stated otherwise, OG&E cannot predict when the regulatory agency will act or what action the regulatory agency will take. OG&E's financial results are dependent in part on timely and adequate decisions by the regulatory agencies that set OG&E's rates. Environmental Compliance Plan On August 6, 2014, OG&E filed an application with the OCC for approval of its plan to comply with the EPA’s MATS and Regional Haze Rule FIP while serving the best long-term interests of customers in light of future environmental uncertainties. The application sought approval of the ECP and for a recovery mechanism for the associated costs. The ECP includes installing Dry Scrubbers at Sooner Units 1 and 2 and the conversion of Muskogee Units 4 and 5 to natural gas. The application also asked the OCC to predetermine the prudence of its Mustang Modernization Plan and approval for a recovery mechanism for the associated costs. On December 2, 2015, OG&E received an order from the OCC denying its plan to comply with the environmental mandates of the Federal Clean Air Act, Regional Haze Rule and MATS. The OCC also denied OG&E's request for pre-approval of its Mustang Modernization Plan, revised depreciation rates for both the retirement of the Mustang units and the replacement combustion turbines and pre-approval of early retirement and replacement of generating units at its Mustang site, including cost recovery through a rider. On February 12, 2016, OG&E filed an application requesting the OCC to issue an order approving its decision to install Dry Scrubbers at the Sooner facility. OG&E's application did not seek approval of the costs of the Dry Scrubber project. Instead, the reasonableness of the costs would be considered after the project is completed, and OG&E seeks recovery in a general rate case. On April 28, 2016, the OCC approved the Dry Scrubber project. Two parties appealed the OCC's decision to the Oklahoma Supreme Court. OG&E is unable to predict what action the Oklahoma Supreme Court may take or the timing of any such action. OG&E anticipates the total cost of Dry Scrubbers will be $542.4 million , including allowance for funds used during construction and capitalized ad valorem taxes and expects the project to be completed in mid to late 2018. As of December 31, 2017 , OG&E had invested $401.3 million in the Dry Scrubbers. OG&E anticipates the total cost for the Mustang Modernization Plan will be $390.0 million , including allowance for funds used during construction and capitalized ad valorem taxes and expects the project to be completed in early 2018. As of December 31, 2017 , OG&E had invested $348.4 million in the Mustang Modernization Plan. Integrated Resource Plans In October 2015, OG&E finalized the 2015 IRP and submitted it to the OCC. The 2015 IRP updated certain assumptions contained in the IRP submitted in 2014 but did not make any material changes to the ECP and other parts of the plan. Currently, OG&E is scheduled to update its IRP in Oklahoma by October 1, 2018 and in Arkansas by October 31, 2018. Demand Program Rider - Energy Efficiency Lost Net Revenues During the May 2017 implementation of new rates, OG&E reserved $5.6 million , pending resolution of a dispute with the OCC's Public Utility Division staff, regarding recovery of certain lost revenues associated with energy efficiency incurred prior to the March 2017 OCC rate order. These lost revenues are included within the total Demand Program Rider regulatory asset balance of $31.6 million as disclosed in Note 1. Fuel Adjustment Clause Review for Calendar Year 2016 On August 3, 2017, the OCC staff filed an application to review OG&E's fuel adjustment clause for calendar year 2016, including the prudence of OG&E's electric generation, purchased power and fuel procurement costs. On February 7, 2018, an intervenor filed a recommendation to disallow the Oklahoma jurisdictional portion of $3.3 million related to wind sales in the SPP. A hearing is scheduled for March 29, 2018. Oklahoma Rate Case Filing - 2018 On January 16, 2018, OG&E filed a general rate case in Oklahoma, requesting a rate increase of $1.9 million per year, assuming a 9.9 percent return on equity. The filing seeks recovery of the seven Mustang combustion turbines that are part of the Mustang Modernization Plan, requests an increase in depreciation rates to levels similar with rates in existence prior to the March 2017 OCC rate order and credits customers for the impacts of the 2017 Tax Act, enacted on December 22, 2017. On December 22, 2017, the Attorney General of Oklahoma requested that the OCC reduce the rates and charges for electric service and provide for any refund due to the customers of OG&E resulting from the 2017 Tax Act. In response, on January 4, 2018, the OCC ordered OG&E to record a reserve, beginning on January 4, 2018, to reflect the reduced federal corporate tax rate of 21 percent and the amortization of excess accumulated deferred income tax and any other tax implications of the 2017 Tax Act on an interim basis, subject to refund until utility rates are adjusted to reflect the federal tax savings and a final order is issued in OG&E's pending rate case filed on January 16, 2018. Further, the OCC ordered the amounts of any refunds of such reserves owed to customers should accrue interest at a rate equivalent to OG&E's cost of capital as previously recognized in the March 2017 OCC rate order. APSC Order - 2017 Tax Act On January 12, 2018, as a result of the 2017 Tax Act, the APSC ordered OG&E to prepare and file an analysis, within 30 days of this order, of the ratemaking effects of the 2017 Tax Act on OG&E's revenue requirement and begin, effective January 1, 2018, to book regulatory liabilities to record the current and deferred impacts of the 2017 Tax Act. The APSC will subsequently solicit comments or testimony regarding the extent of the impacts of the 2017 Tax Act and how any resulting benefits, including carrying charges, should be returned to customers. FERC - Section 206 Filing In January 2018, the Oklahoma Municipal Power Authority filed a complaint at the FERC stating that the base return on common equity used by OG&E in calculating formula transmission rates under the SPP Open Access Transmission Tariff is unjust and unreasonable and should be reduced from 10.60 percent to 7.85 percent , effective upon the date of the complaint. OG&E is analyzing the potential impact of the complaint but estimates that if the FERC ultimately orders a reduction, each 25 basis point reduction in the requested return on equity would reduce OG&E's SPP Open Access Transmission Tariff transmission revenues by approximately $1.5 million annually. In addition to the request to reduce the return on equity, the Oklahoma Municipal Power Authority's complaint also requests that modifications be made to OG&E's transmission formula rates to reflect the impacts of the 2017 Tax Act. Although the proceeding is in the early stages, OG&E expects to contest the reduction of its base return on equity. OG&E is unable to predict what action the FERC will take in response to the Oklahoma Municipal Power Authority's complaint or the timing of such action. However, if the FERC orders revenue reductions as a result of the complaint, including refunds from the date of the complaint filing, it could have a material adverse effect on OG&E's financial position, results of operations and cash flows. |
Quarterly Financial Data
Quarterly Financial Data | 12 Months Ended |
Dec. 31, 2017 | |
Quarterly Financial Data [Abstract] | |
Quarterly Financial Information [Text Block] | Quarterly Financial Data (Unaudited) Due to the seasonal fluctuations and other factors of OG&E's business, the operating results for interim periods are not necessarily indicative of the results that may be expected for the year. In OG&E's opinion, the following quarterly financial data includes all adjustments, consisting of normal recurring adjustments, necessary to fairly present such amounts. Summarized quarterly unaudited financial data is as follows: Quarter Ended ( In millions) March 31 June 30 September 30 December 31 Total Operating revenues 2017 $ 456.0 $ 586.4 $ 716.8 $ 501.9 $ 2,261.1 2016 $ 433.1 $ 551.4 $ 743.9 $ 530.8 $ 2,259.2 Operating income 2017 $ 45.6 $ 145.7 $ 243.6 $ 92.2 $ 527.1 2016 $ 38.8 $ 131.8 $ 257.3 $ 81.8 $ 509.7 Net income 2017 $ 16.2 $ 86.2 $ 161.5 $ 41.6 $ 305.5 2016 $ 6.1 $ 72.3 $ 159.9 $ 45.8 $ 284.1 |
Summary of Significant Accoun23
Summary of Significant Accounting Policies (Policies) | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Organization, Consolidation and Presentation of Financial Statements [Abstract] | ||
Public Utilities, Policy [Policy Text Block] | Accounting Records The accounting records of OG&E are maintained in accordance with the Uniform System of Accounts prescribed by the FERC and adopted by the OCC and the APSC. Additionally, OG&E, as a regulated utility, is subject to accounting principles for certain types of rate-regulated activities, which provide that certain incurred costs that would otherwise be charged to expense can be deferred as regulatory assets, based on the expected recovery from customers in future rates. Likewise, certain actual or anticipated credits that would otherwise reduce expense can be deferred as regulatory liabilities, based on the expected flowback to customers in future rates. Management's expected recovery of deferred costs and flowback of deferred credits generally results from specific decisions by regulators granting such ratemaking treatment. OG&E records certain incurred costs and obligations as regulatory assets or liabilities if, based on regulatory orders or other available evidence, it is probable that the costs or obligations will be included in amounts allowable for recovery or refund in future rates. Management continuously monitors the future recoverability of regulatory assets. When, in management's judgment, future recovery becomes impaired, the amount of the regulatory asset is adjusted, as appropriate. If OG&E were required to discontinue the application of accounting principles for certain types of rate-regulated activities for some or all of its operations, it could result in writing off the related regulatory assets, which could have significant financial effects. | |
Use of Estimates, Policy [Policy Text Block] | Use of Estimates In preparing the Financial Statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and contingent liabilities at the date of the Financial Statements and the reported amounts of revenues and expenses during the reporting period. Changes to these assumptions and estimates could have a material effect on OG&E's Financial Statements. However, OG&E believes it has taken reasonable positions where assumptions and estimates are used in order to minimize the negative financial impact to OG&E that could result if actual results vary from the assumptions and estimates. In management's opinion, the areas of OG&E where the most significant judgment is exercised includes the determination of Pension Plan assumptions, income taxes, contingency reserves, asset retirement obligations , depreciable lives of property, plant and equipment , regulatory assets and liabilities and unbilled revenues . | |
Cash and Cash Equivalents, Policy [Policy Text Block] | Cash and Cash Equivalents For purposes of the Financial Statements, OG&E considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. These investments are carried at cost, which approximates fair value. | |
Allowance for Doubtful Accounts, Policy [Policy Text Block] | Allowance for Uncollectible Accounts Receivable Customer balances are generally written off if not collected within six months after the final billing date. The allowance for uncollectible accounts receivable for OG&E is calculated by multiplying the last six months of electric revenue by the provision rate, which is based on a 12-month historical average of actual balances written off. To the extent the historical collection rates are not representative of future collections, there could be an effect on the amount of uncollectible expense recognized. Also, a portion of the uncollectible provision related to fuel within the Oklahoma jurisdiction is being recovered through the fuel adjustment clause. The allowance for uncollectible accounts receivable is a reduction to Accounts Receivable on the Balance Sheets and is included in the Other Operation and Maintenance Expense on the Statements of Income. The allowance for uncollectible accounts receivable was $1.5 million at both December 31, 2017 and 2016 . New business customers are required to provide a security deposit in the form of cash, bond or irrevocable letter of credit that is refunded when the account is closed. New residential customers whose outside credit scores indicate an elevated risk are required to provide a security deposit that is refunded based on customer protection rules defined by the OCC and the APSC. The payment behavior of all existing customers is continuously monitored, and, if the payment behavior indicates sufficient risk within the meaning of the applicable utility regulation, customers will be required to provide a security deposit. | |
Inventory, Policy [Policy Text Block] | Fuel Inventories Fuel inventories for the generation of electricity consist of coal, natural gas and oil. OG&E uses the weighted-average cost method of accounting for inventory that is physically added to or withdrawn from storage or stockpiles. The amount of fuel inventory was $84.3 million and $82.4 million at December 31, 2017 and 2016 , respectively. | |
Property, Plant and Equipment, Policy [Policy Text Block] | Property, Plant and Equipment All property, plant and equipment is recorded at cost. Newly constructed plant is added to plant balances at cost which includes contracted services, direct labor, materials, overhead, transportation costs and the allowance for funds used during construction. Replacements of units of property are capitalized as plant. For assets that belong to a common plant account, the replaced plant is removed from plant balances, and the cost of such property is charged to Accumulated Depreciation. For assets that do not belong to a common plant account, the replaced plant is removed from plant balances with the related accumulated depreciation, and the remaining balance net of any salvage proceeds is recorded as a loss in the Statements of Income as Other Expense. Repair and replacement of minor items of property are included in the Statements of Income as Other Operation and Maintenance Expense. | |
Depreciation and Amortization, Policy [Policy Text Block] | Depreciation and Amortization The provision for depreciation, which was 2.5 percent and 3.0 percent of the average depreciable utility plant for 2017 and 2016 , respectively, is calculated using the straight-line method over the estimated service life of the utility assets. Depreciation is provided at the unit level for production plant and at the account or sub-account level for all other plant and is based on the average life group method. In 2018 , the provision for depreciation is projected to be 2.7 percent of the average depreciable utility plant. Amortization of intangible assets is calculated using the straight-line method. Of the remaining amortizable intangible plant balance at December 31, 2017 , 98.6 percent will be amortized over 10.4 years with the remaining 1.4 percent of the intangible plant balance at December 31, 2017 being amortized over 23.7 years. Amortization of plant acquisition adjustments is provided on a straight-line basis over the estimated remaining service life of the acquired asset. Plant acquisition adjustments include $148.3 million for the Redbud Plant, which is being amortized over a 27 year life and $3.3 million for certain transmission substation facilities in OG&E's service territory, which are being amortized over a 37 to 59 year period. | |
Asset Retirement Obligation [Policy Text Block] | Asset Retirement Obligations OG&E has asset retirement obligations primarily associated with the removal of company-owned wind turbines on leased land, as well as the removal of asbestos from certain power generating stations. OG&E has recorded asset retirement obligations that are being accreted over their respective lives ranging from three to 74 years. | |
Allowance for Funds Used During Construction, Policy [Policy Text Block] | Allowance for Funds Used During Construction Allowance for funds used during construction, a non-cash item, is reflected as an increase to net Other Income and a reduction to Interest Expense in the Statements of Income and as an increase to Construction Work in Progress in the Balance Sheets. Allowance for funds used during construction is calculated according to the FERC requirements for the imputed cost of equity and borrowed funds. Allowance for funds used during construction rates, compounded semi-annually, were 8.2 percent , 8.2 percent and 8.1 percent for the years ended December 31, 2017 , 2016 and 2015 , respectively. | |
Collection of Sales Tax, Policy [Policy Text Block] | Collection of Sales Tax In the normal course of its operations, OG&E collects sales tax from its customers. OG&E records a current liability for sales taxes when it bills its customers and eliminates this liability when the taxes are remitted to the appropriate governmental authorities. OG&E excludes the sales tax collected from its operating revenues. | |
Revenue Recognition, Policy [Policy Text Block] | General OG&E recognizes revenue from electric sales when power is delivered to customers. OG&E reads its customers' meters and sends bills to its customers throughout each month. As a result, there is a significant amount of customers' electricity consumption that has not been billed at the end of each month. OG&E accrues an estimate of the revenues for electric sales delivered since the latest billings. Unbilled revenue is presented in Accrued Unbilled Revenues on the Balance Sheets and in Operating Revenues on the Statements of Income based on estimates of usage and prices during the period. The estimates that management uses in this calculation could vary from the actual amounts to be paid by customers. SPP Purchases and Sales OG&E currently owns and operates transmission and generation facilities as part of a vertically integrated utility. OG&E is a member of the SPP regional transmission organization and has transferred operational authority, but not ownership, of OG&E's transmission facilities to the SPP. The SPP has implemented FERC-approved regional day-ahead and real-time markets for energy and operating services, as well as associated transmission congestion rights. Collectively, the three markets operate together under the global name, SPP Integrated Marketplace. OG&E represents owned- and contracted-generation assets and customer load in the SPP Integrated Marketplace for the sole benefit of its customers. OG&E has not participated in the SPP Integrated Marketplace for any speculative trading activities. OG&E records the SPP Integrated Marketplace transactions as sales or purchases per FERC Order 668, which requires that purchases and sales be recorded on a net basis for each settlement period of the SPP Integrated Marketplace. These results are reported as Operating Revenues or Cost of Sales in the Financial Statements. OG&E revenues, expenses, assets and liabilities may be adversely affected by changes in the organization, operating and regulation by the FERC or the SPP. | |
Fuel Adjustment Clauses, Policy [Policy Text Block] | Fuel Adjustment Clauses The actual cost of fuel used in electric generation and certain purchased power costs are passed through to OG&E's customers through fuel adjustment clauses. The fuel adjustment clauses are subject to periodic review by the OCC and the APSC. | |
Income Taxes, Policy [Policy Text Block] | Income Taxes OG&E is a member of an affiliated group that file s consolidated income tax returns in the U.S. federal jurisdiction and various state jurisdictions . Income taxes are generally allocated to each company in the affiliated group based on its stand-alone taxable income or loss. Federal investment tax credits previously claimed on electric utility property have been deferred and are being amortized to income over the life of the related property. OG&E uses the asset and liability method of accounting for income taxes. Under this method, a deferred tax asset or liability is recognized for the estimated future tax effects attributable to temporary differences between the financial statement basis and the tax basis of assets and liabilities as well as tax credit carry forwards and net operating loss carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the period of the change. OG&E recognizes interest related to unrecognized tax benefits in Interest Expense and recognizes penalties in Other Expense in the Statements of Income. On December 22, 2017, President Trump signed the 2017 Tax Act into law, significantly changing U.S. corporate income tax laws. The 2017 Tax Act reduces the corporate federal tax rate from 35 percent to 21 percent for tax years beginning after December 31, 2017. See Note 7 for further discussion of the effects of the 2017 Tax Act. | |
Accrued Vacation, Policy [Policy Text Block] | Accrued Vacation OG&E accrues vacation pay monthly by establishing a liability for vacation earned. Vacation may be taken as earned and is charged against the liability. At the end of each year, the liability represents the amount of vacation earned but not taken. | |
Environmental Costs, Policy [Policy Text Block] | Environmental Costs Accruals for environmental costs are recognized when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated. Costs are charged to expense or deferred as a regulatory asset based on expected recovery from customers in future rates, if they relate to the remediation of conditions caused by past operations or if they are not expected to mitigate or prevent contamination from future operations. Where environmental expenditures relate to facilities currently in use, such as pollution control equipment, the costs may be capitalized and depreciated over the future service periods. Estimated remediation costs are recorded at undiscounted amounts, independent of any insurance or rate recovery, based on prior experience, assessments and current technology. Accrued obligations are regularly adjusted as environmental assessments and estimates are revised and remediation efforts proceed. For sites where OG&E has been designated as one of several potentially responsible parties, the amount accrued represents OG&E's estimated share of the cost. OG&E had $17.1 million and $13.9 million in accrued environmental liabilities at December 31, 2017 and 2016 , respectively, which are included in OG&E's asset retirement obligations. | |
Related Party Transactions [Policy Text Block] | OGE Energy charges operating costs to OG&E based on several factors. Operating costs directly related to OG&E are assigned as such. Operating costs incurred for the benefit of OG&E are allocated either as overhead based primarily on labor costs or using the "Distrigas" method. | |
Fair Value of Financial Instruments, Policy [Policy Text Block] | Fair Value Measurements The classification of OG&E's fair value measurements requires judgment regarding the degree to which market data is observable or corroborated by observable market data. GAAP establishes a fair value hierarchy that prioritizes the inputs used to measure fair value based on observable and unobservable data. The hierarchy categorizes the inputs into three levels, with the highest priority given to quoted prices in active markets for identical unrestricted assets or liabilities (Level 1) and the lowest priority given to unobservable inputs (Level 3). Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The three levels defined in the fair value hierarchy are as follows: Level 1 inputs are quoted prices in active markets for identical unrestricted assets or liabilities that are accessible at the measurement date. Level 2 inputs are inputs other than quoted prices in active markets included within Level 1 that are either directly or indirectly observable at the reporting date for the asset or liability for substantially the full term of the asset or liability. Level 2 inputs include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Level 3 inputs are prices or valuation techniques for the asset or liability that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). Unobservable inputs reflect the reporting entity's own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). The fair value of OG&E's long-term debt is based on quoted market prices and estimates of current rates available for similar issues with similar maturities and is classified as Level 2 in the fair value hierarchy with the exception of the Tinker Debt whose fair value is based on calculating the net present value of the monthly payments discounted by OG&E's current borrowing rate and is classified as Level 3 in the fair value hierarchy. | |
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] | Performance Units Under the Stock Incentive Plan, OGE Energy has issued performance units which represent the value of one share of OGE Energy's common stock. The performance units provide for accelerated vesting if there is a change in control (as defined in the Stock Incentive Plan). Each performance unit is subject to forfeiture if the recipient terminates employment with OGE Energy or a subsidiary prior to the end of the primarily three-year award cycle for any reason other than death, disability or retirement. In the event of death, disability or retirement, a participant will receive a prorated payment based on such participant's number of full months of service during the award cycle, further adjusted based on the achievement of the performance goals during the award cycle. The performance units granted based on total shareholder return are contingently awarded and will be payable in shares of OGE Energy's common stock subject to the condition that the number of performance units, if any, earned by the employees upon the expiration of a primarily three-year award cycle (i.e., three-year cliff vesting period) is dependent on OGE Energy's total shareholder return ranking relative to a peer group of companies. The performance units granted based on earnings per share are contingently awarded and will be payable in shares of OGE Energy's common stock based on OGE Energy's earnings per share growth over a primarily three-year award cycle (i.e., three-year cliff vesting period) compared to a target set at the time of the grant by the Compensation Committee of OGE Energy's Board of Directors. All of these performance units are classified as equity in OGE Energy's Consolidated Balance Sheets. If there is no or only a partial payout for the performance units at the end of the award cycle, the unearned performance units are cancelled. Payout requires approval of the Compensation Committee of OGE Energy's Board of Directors. Payouts, if any, are all made in common stock and are considered made when the payout is approved by the Compensation Committee. Performance Units – Total Shareholder Return The fair value of the performance units based on total shareholder return was estimated on the grant date using a lattice-based valuation model that factors in information, including the expected dividend yield, expected price volatility, risk-free interest rate and the probable outcome of the market condition, over the expected life of the performance units. Compensation expense for the performance units is a fixed amount determined at the grant date fair value and is recognized over the primarily three-year award cycle regardless of whether performance units are awarded at the end of the award cycle. Dividends were not accrued or paid for awards prior to February 2014 and were therefore not included in the fair value calculation. Beginning with the February 2014 performance unit awards, dividends are accrued on a quarterly basis pending achievement of payout criteria and were therefore included in the fair value calculations. Expected price volatility is based on the historical volatility of OGE Energy's common stock for the past three years and was simulated using the Geometric Brownian Motion process. The risk-free interest rate for the performance unit grants is based on the three-year U.S. Treasury yield curve in effect at the time of the grant. The expected life of the units is based on the non-vested period since inception of the award cycle. There are no post-vesting restrictions related to OGE Energy's performance units based on total shareholder return. Restricted Stock Under the Stock Incentive Plan, OGE Energy issued restricted stock to certain existing non-officer employees as well as other executives upon hire to attract and retain individuals to be competitive in the marketplace. The restricted stock vests in one-third annual increments. Prior to vesting, each share of restricted stock is subject to forfeiture if the recipient ceases to render substantial services to OGE Energy or a subsidiary for any reason other than death, disability or retirement. These shares may not be sold, assigned, transferred or pledged and are subject to a risk of forfeiture. The fair value of the restricted stock was based on the closing market price of OGE Energy's common stock on the grant date. Compensation expense for the restricted stock is a fixed amount determined at the grant date fair value and is recognized as services are rendered by employees over a primarily three-year vesting period. Also, OG&E treats its restricted stock as multiple separate awards by recording compensation expense separately for each tranche whereby a substantial portion of the expense is recognized in the earlier years in the requisite service period. Dividends are accrued and paid during the vesting period on restricted stock granted prior to July 2014; therefore, dividends are included in the fair value calculation for such restricted stock granted prior to July 2014. For restricted stock granted after July 2014, dividends will only be paid on restricted stock awards that vest. Accordingly, for restricted stock granted after July 2014, only the present value of dividends expected to vest are included in the fair value calculations. The expected life of the restricted stock is based on the non-vested period since inception of the primarily three-year award cycle. There are no post-vesting restrictions related to OGE Energy's restricted stock. Performance Units – Earnings Per Share The fair value of the performance units based on earnings per share is based on grant date fair value which is equivalent to the price of one share of OGE Energy's common stock on the date of grant. The fair value of performance units based on earnings per share varies as the number of performance units that will vest is based on the grant date fair value of the units and the probable outcome of the performance condition. OGE Energy reassesses at each reporting date whether achievement of the performance condition is probable and accrues compensation expense if and when achievement of the performance condition is probable. As a result, the compensation expense recognized for these performance units can vary from period to period. There are no post-vesting restrictions related to OGE Energy's performance units based on earnings per share. | |
Pension and Other Postretirement Plans, Policy [Policy Text Block] | OGE Energy provides a Restoration of Retirement Income Plan to those participants in OGE Energy's Pension Plan whose benefits are subject to certain limitations of the Code. Participants in the Restoration of Retirement Income Plan receive the same benefits that they would have received under OGE Energy's Pension Plan in the absence of limitations imposed by the federal tax laws. The Restoration of Retirement Income Plan is intended to be an unfunded plan. Pension Plan and Restoration of Retirement Income Plan OG&E's employees participate in OGE Energy's Pension Plan and Restoration of Retirement Income Plan. It is OGE Energy's policy to fund the Pension Plan on a current basis based on the net periodic pension expense as determined by OGE Energy's actuarial consultants. Such contributions are intended to provide not only for benefits attributed to service to date but also for those expected to be earned in the future. OGE Energy made a $20.0 million contribution to its Pension Plan in both 2017 and 2016 , of which $4.0 million is related to OG&E in 2017 compared to no contributions related to OG&E in 2016 . OGE Energy has not determined whether it will need to make any contributions to the Pension Plan in 2018 . Any contribution to the Pension Plan during 2018 would be a discretionary contribution, anticipated to be in the form of cash, and is not required to satisfy the minimum regulatory funding requirement specified by the Employee Retirement Income Security Act of 1974, as amended. OGE Energy could be required to make additional contributions if the value of its pension trust and postretirement benefit plan trust assets are adversely impacted by a major market disruption in the future. In accordance with ASC Topic 715, "Compensation - Retirement Benefits," a one-time settlement charge is required to be recorded by an organization when lump sum payments or other settlements that relieve the organization from the responsibility for the pension benefit obligation during a plan year exceed the service cost and interest cost components of the organization’s net periodic pension cost. During 2017 and 2015, OG&E experienced an increase in both the number of employees electing to retire and the amount of lump sum payments paid to such employees upon retirement. As a result, OG&E recorded pension settlement charges of $11.7 million in the fourth quarter of 2017 and $14.2 million during 2015, of which $10.8 million and $12.5 million , respectively, related to OG&E's Oklahoma jurisdiction and has been included in the Pension tracker. The pension settlement charges did not increase OG&E's total pension expense over time, as the charges were an acceleration of costs that otherwise would be recognized as pension expense in future periods. During the quarter ended June 30, 2016, OG&E experienced a settlement of its non-qualified Restoration of Retirement Income Plan. As a result, OG&E recorded pension settlement charges of $0.4 million during 2016, of which $0.4 million related to OG&E's Oklahoma jurisdiction and has been included in the Pension tracker. | Postretirement Benefit Plans In addition to providing pension benefits, OGE Energy provides certain medical and life insurance benefits for eligible retired members. Regular, full-time, active employees hired prior to February 1, 2000 whose age and years of credited service total or exceed 80 or have attained at least age 55 with 10 or more years of service at the time of retirement are entitled to postretirement medical benefits, while employees hired on or after February 1, 2000 are not entitled to postretirement medical benefits. Eligible retirees must contribute such amount as OGE Energy specifies from time to time toward the cost of coverage for postretirement benefits. The benefits are subject to deductibles, co-payment provisions and other limitations. OG&E charges postretirement benefit costs to expense and includes an annual amount as a component of the cost-of-service in future ratemaking proceedings. The three levels defined in the fair value hierarchy and examples of each are as follows: Level 1 inputs are quoted prices in active markets for identical unrestricted assets or liabilities that are accessible by the Pension Plan at the measurement date. Instruments classified as Level 1 include investments in common stocks, U.S. Treasury notes and bonds, mutual funds and cash collateral. Level 2 inputs are inputs other than quoted prices in active markets included within Level 1 that are either directly or indirectly observable at the reporting date for the asset or liability for substantially the full term of the asset or liability. Level 2 inputs include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Instruments classified as Level 2 include corporate fixed income and other securities, mortgage- and asset-backed securities, U.S. municipal bonds, foreign government bonds, U.S. Treasury futures contracts and forward contracts. Level 3 inputs are prices or valuation techniques for the asset or liability that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). Unobservable inputs reflect the Plan's own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). |
Plan Investments, Policies and Strategies, Policy [Policy Text Block] | Pension Plan Investments, Policies and Strategies The Pension Plan assets are held in a trust which follows an investment policy and strategy designed to reduce the funded status volatility of the Plan by utilizing liability driven investing. The purpose of liability-driven investing is to structure the asset portfolio to more closely resemble the pension liability and thereby more effectively hedge against changes in the liability. The investment policy follows a glide path approach that shifts a higher portfolio weighting to fixed income as the Plan's funded status increases. The table below sets forth the targeted fixed income and equity allocations at different funded status levels. Projected Benefit Obligation Funded Status Thresholds <90% 95% 100% 105% 110% 115% 120% Fixed income 50% 58% 65% 73% 80% 85% 90% Equity 50% 42% 35% 27% 20% 15% 10% Total 100% 100% 100% 100% 100% 100% 100% Within the portfolio's overall allocation to equities, the funds are allocated according to the guidelines in the table below. Asset Class Target Allocation Minimum Maximum Domestic Large Cap Equity 40% 35% 60% Domestic Mid-Cap Equity 15% 5% 25% Domestic Small-Cap Equity 25% 5% 30% International Equity 20% 10% 30% OGE Energy has retained an investment consultant responsible for the general investment oversight, analysis, monitoring investment guideline compliance and providing quarterly reports to certain of OG&E's members and OGE Energy's Investment Committee. The various investment managers used by the trust operate within the general operating objectives as established in the investment policy and within the specific guidelines established for each investment manager's respective portfolio. The portfolio is rebalanced at least on an annual basis to bring the asset allocations of various managers in line with the target asset allocation listed above. More frequent rebalancing may occur if there are dramatic price movements in the financial markets which may cause the trust's exposure to any asset class to exceed or fall below the established allowable guidelines. To evaluate the progress of the portfolio, investment performance is reviewed quarterly. It is, however, expected that performance goals will be met over a full market cycle, normally defined as a three to five year period. Analysis of performance is within the context of the prevailing investment environment and the advisors' investment style. The goal of the trust is to provide a rate of return consistently from three percent to five percent over the rate of inflation (as measured by the national Consumer Price Index) on a fee adjusted basis over a typical market cycle of no less than three years and no more than five years. Each investment manager is expected to outperform its respective benchmark. Below is a list of each asset class utilized with appropriate comparative benchmark(s) each manager is evaluated against: Asset Class Comparative Benchmark(s) Active Duration Fixed Income Bloomberg Barclays Aggregate Long Duration Fixed Income Duration blended Barclays Long Government/Credit & Barclays Universal Equity Index Standard & Poor's 500 Index Mid-Cap Equity Russell Midcap Index Russell Midcap Value Index Small-Cap Equity Russell 2000 Index Russell 2000 Value Index International Equity Morgan Stanley Capital Investment ACWI ex-U.S. The fixed income managers are expected to use discretion over the asset mix of the trust assets in its efforts to maximize risk-adjusted performance. Exposure to any single issuer, other than the U.S. government, its agencies or its instrumentalities (which have no limits), is limited to five percent of the fixed income portfolio as measured by market value. At least 75 percent of the invested assets must possess an investment-grade rating at or above Baa3 or BBB- by Moody's Investors Services, Standard & Poor's Ratings Services or Fitch Ratings. The portfolio may invest up to 10 percent of the portfolio's market value in convertible bonds as long as the securities purchased meet the quality guidelines. A portfolio may invest up to 15 percent of the portfolio's market value in private placement, including 144A securities with or without registration rights and allow for futures to be traded in the portfolio. The purchase of any of OGE Energy's equity, debt or other securities is prohibited. The domestic value equity managers focus on stocks that the manager believes are undervalued in price and earn an average or less than average return on assets and often pays out higher than average dividend payments. The domestic growth equity manager will invest primarily in growth companies which consistently experience above average growth in earnings and sales, earn a high return on assets and reinvest cash flow into existing business. The domestic mid-cap equity portfolio manager focuses on companies with market capitalizations lower than the average company traded on the public exchanges with the following characteristics: price/earnings ratio at or near the Russell Midcap Index, small dividend yield, return on equity at or near the Russell Midcap Index and an earnings per share growth rate at or near the Russell Midcap Index. The domestic small-cap equity manager will purchase shares of companies with market capitalizations lower than the average company traded on the public exchanges with the following characteristics: price/earnings ratio at or near the Russell 2000, small dividend yield, return on equity at or near the Russell 2000 and an earnings per share growth rate at or near the Russell 2000. The international global equity manager invests primarily in non-dollar denominated equity securities. Investing internationally diversifies the overall trust across the global equity markets. The manager is required to operate under certain restrictions including regional constraints, diversification requirements and percentage of U.S. securities. The Morgan Stanley Capital International All Country World ex-U.S. Index is the benchmark for comparative performance purposes. The Morgan Stanley Capital International All Country World ex-U.S. Index is a market value weighted index designed to measure the combined equity market performance of developed and emerging markets countries, excluding the U.S. All of the equities which are purchased for the international portfolio are thoroughly researched. All securities are freely traded on a recognized stock exchange, and there are no over-the-counter derivatives. The following investment categories are excluded: options (other than traded currency options), commodities, futures (other than currency futures or currency hedging), short sales/margin purchases, private placements, unlisted securities and real estate (but not real estate shares). For all domestic equity investment managers, no more than five percent can be invested in any one stock at the time of purchase and no more than 10 percent after accounting for price appreciation. Options or financial futures may not be purchased unless prior approval of OGE Energy's Investment Committee is received. The purchase of securities on margin is prohibited as is securities lending. Private placement or venture capital may not be purchased. All interest and dividend payments must be swept on a daily basis into a short-term money market fund for re-deployment. The purchase of any of OGE Energy's equity, debt or other securities is prohibited. The purchase of equity or debt issues of the portfolio manager's organization is also prohibited. The aggregate positions in any company may not exceed one percent of the fair market value of its outstanding stock. | |
Postemployment Benefit Plans, Policy [Policy Text Block] | Post-Employment Benefit Plan Disabled employees receiving benefits from OGE Energy's Group Long-Term Disability Plan are entitled to continue participating in OGE Energy's Medical Plan along with their dependents. The post-employment benefit obligation represents the actuarial present value of estimated future medical benefits that are attributed to employee service rendered prior to the date as of which such information is presented. The obligation also includes future medical benefits expected to be paid to current employees participating in OGE Energy's Group Long-Term Disability Plan and their dependents, as defined in OGE Energy's Medical Plan. The post-employment benefit obligation is determined by an actuary on a basis similar to the accumulated postretirement benefit obligation. The estimated future medical benefits are projected to grow with expected future medical cost trend rates and are discounted for interest at the discount rate and for the probability that the participant will discontinue receiving benefits from OGE Energy's Group Long-Term Disability Plan due to death, recovery from disability or eligibility for retiree medical benefits. OG&E's post-employment benefit obligation was $2.2 million and $2.1 million at December 31, 2017 and 2016 , respectively. | |
Pension and Other Postretirement Plans, Nonpension Benefits, Policy [Policy Text Block] | 401(k) Plan OGE Energy provides a 401(k) Plan, and each regular full-time employee of OGE Energy or a participating affiliate is eligible to participate in the 401(k) Plan immediately. All other employees of OGE Energy or a participating affiliate are eligible to become participants in the 401(k) Plan after completing one year of service as defined in the 401(k) Plan. Participants may contribute each pay period any whole percentage between two percent and 19 percent of their compensation, as defined in the 401(k) Plan, for that pay period. Participants who have reached age 50 before the close of a year are allowed to make additional contributions referred to as "Catch-Up Contributions," subject to certain limitations of the Code. Participants may designate, at their discretion, all or any portion of their contributions as: (i) a before-tax contribution under Section 401(k) of the Code subject to the limitations thereof, (ii) a contribution made on a non-Roth after-tax basis or (iii) a Roth contribution. The 401(k) Plan also includes an eligible automatic contribution arrangement and provides for a qualified default investment alternative consistent with the U.S. Department of Labor regulations. Participants may elect, in accordance with the 401(k) Plan procedures, to have his or her future salary deferral rate to be automatically increased annually on a date and in an amount as specified by the participant in such election. For employees hired or rehired on or after December 1, 2009, OGE Energy contributes to the 401(k) Plan, on behalf of each participant, 200 percent of the participant's contributions up to five percent of compensation. No OGE Energy contributions are made with respect to a participant's Catch-Up Contributions, rollover contributions or with respect to a participant's contributions based on overtime payments, pay-in-lieu of overtime for exempt personnel, special lump-sum recognition awards and lump-sum merit awards included in compensation for determining the amount of participant contributions. Once made, OGE Energy's contribution may be directed to any available investment option in the 401(k) Plan. OGE Energy match contributions vest over a three -year period. After two years of service, participants become 20 percent vested in their OGE Energy contribution account and become fully vested on completing three years of service. In addition, participants fully vest when they are eligible for normal or early retirement under the Pension Plan requirements, in the event of their termination due to death or permanent disability or upon attainment of age 65 while employed by OGE Energy or its affiliates. OG&E contributed $9.7 million , $8.8 million and $8.2 million in 2017 , 2016 and 2015 , respectively, to the 401(k) Plan. Deferred Compensation Plan OGE Energy provides a nonqualified deferred compensation plan which is intended to be an unfunded plan. The plan's primary purpose is to provide a tax-deferred capital accumulation vehicle for a select group of management, highly compensated employees and non-employee members of the Board of Directors of OGE Energy and to supplement such employees' 401(k) Plan contributions as well as offering this plan to be competitive in the marketplace. Eligible employees who enroll in the plan have the following deferral options: (i) eligible employees may elect to defer up to a maximum of 70 percent of base salary and 100 percent of annual bonus awards or (ii) eligible employees may elect a deferral percentage of base salary and bonus awards based on the deferral percentage elected for a year under the 401(k) Plan with such deferrals to start when maximum deferrals to the qualified 401(k) Plan have been made because of limitations in that plan. Eligible directors who enroll in the plan may elect to defer up to a maximum of 100 percent of directors' meeting fees and annual retainers. OGE Energy matches employee (but not non-employee director) deferrals to make up for any match lost in the 401(k) Plan because of deferrals to the deferred compensation plan and to allow for a match that would have been made under the 401(k) Plan on that portion of either the first six percent of total compensation or the first five percent of total compensation, depending on prior participant elections, deferred that exceeds the limits allowed in the 401(k) Plan. Matching credits vest based on years of service, with full vesting after three years or, if earlier, on retirement, disability, death, a change in control of OGE Energy or termination of the plan. Deferrals, plus any OGE Energy match, are credited to a recordkeeping account in the participant's name. Earnings on the deferrals are indexed to the assumed investment funds selected by the participant. In 2017 , those investment options included an OGE Energy Common Stock fund, whose value was determined based on the stock price of OGE Energy's Common Stock. |
Summary of Significant Accoun24
Summary of Significant Accounting Policies (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
Schedule of Regulatory Assets and Liabilities [Table Text Block] | The following table is a summary of OG&E's regulatory assets and liabilities: December 31 (In millions) 2017 2016 Regulatory Assets Current: Oklahoma demand program rider under recovery (A) $ 31.6 $ 51.0 SPP cost tracker under recovery (A) 7.7 10.0 Fuel clause under recoveries — 51.3 Other (A) 1.5 9.5 Total current regulatory assets $ 40.8 $ 121.8 Non-current: Benefit obligations regulatory asset $ 177.2 $ 232.6 Deferred storm expenses 42.2 35.7 Smart Grid 32.8 43.2 Unamortized loss on reacquired debt 12.3 13.4 Income taxes recoverable from customers, net — 62.3 Other 18.5 17.6 Total non-current regulatory assets $ 283.0 $ 404.8 Regulatory Liabilities Current: Fuel clause over recoveries $ 1.7 $ — Other (B) 2.2 12.3 Total current regulatory liabilities $ 3.9 $ 12.3 Non-current: Income taxes refundable to customers, net $ 955.5 $ — Accrued removal obligations, net 288.4 262.8 Pension tracker 32.3 35.5 Other 7.2 1.4 Total non-current regulatory liabilities $ 1,283.4 $ 299.7 (A) Included in Other Current Assets on the Balance Sheets. (B) Included in Other Current Liabilities on the Balance Sheets. |
Components of Benefit Obligation Regulatory Asset [Table Text Block] | The following table is a summary of the components of the benefit obligations regulatory asset: December 31 (In millions) 2017 2016 Pension Plan and Restoration of Retirement Income Plan: Net loss $ 172.4 $ 199.9 Postretirement Benefit Plans: Net loss 33.6 32.7 Prior service cost (28.8 ) — Total $ 177.2 $ 232.6 |
Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block] | The following amounts in the benefit obligations regulatory asset at December 31, 2017 are expected to be recognized as components of net periodic benefit cost in 2018 : (In millions) Pension Plan and Restoration of Retirement Income Plan: Net loss $ 12.5 Postretirement Benefit Plans: Net loss 4.0 Prior service cost (6.1 ) Total $ 10.4 |
Schedule of Jointly Owned Utility Plants [Table Text Block] | The tables below present OG&E's ownership interest in the jointly-owned McClain Plant and the jointly-owned Redbud Plant, and, as disclosed below, only OG&E's ownership interest is reflected in the property, plant and equipment and accumulated depreciation balances in these tables. The owners of the remaining interests in the McClain Plant and the Redbud Plant are responsible for providing their own financing of capital expenditures. Also, only OG&E's proportionate interests of any direct expenses of the McClain Plant and the Redbud Plant, such as fuel, maintenance expense and other operating expenses, are included in the applicable financial statement captions in the Statements of Income. December 31, 2017 (In millions) Percentage Ownership Total Property, Plant and Equipment Accumulated Depreciation Net Property, Plant and Equipment McClain Plant (A) 77 % $ 226.8 $ 71.4 $ 155.4 Redbud Plant (A)(B) 51 % $ 496.6 $ 136.0 $ 360.6 (A) Construction work in progress was $0.4 million and $7.8 million for the McClain and Redbud Plants, respectively. (B) This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $50.8 million . December 31, 2016 (In millions) Percentage Ownership Total Property, Plant and Equipment Accumulated Depreciation Net Property, Plant and Equipment McClain Plant (A) 77 % $ 234.2 $ 72.3 $ 161.9 Redbud Plant (A)(B) 51 % $ 489.0 $ 121.0 $ 368.0 (A) Construction work in progress was $0.2 million and $1.8 million for the McClain and Redbud Plants, respectively. (B) This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $45.3 million . |
Property, Plant and Equipment [Table Text Block] | OG&E's property, plant and equipment and related accumulated depreciation are divided into the following major classes: December 31, 2017 (In millions) Total Property, Plant and Equipment Accumulated Depreciation Net Property, Plant and Equipment Distribution assets $ 4,057.1 $ 1,259.1 $ 2,798.0 Electric generation assets (A) 4,475.0 1,493.5 2,981.5 Transmission assets (B) 2,767.7 506.5 2,261.2 Intangible plant 181.8 135.8 46.0 Other property and equipment 421.0 173.9 247.1 Total property, plant and equipment $ 11,902.6 $ 3,568.8 $ 8,333.8 (A) This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $50.8 million . (B) This amount includes a plant acquisition adjustment of $3.3 million and accumulated amortization of $0.6 million . December 31, 2016 (In millions) Total Property, Plant and Equipment Accumulated Depreciation Net Property, Plant and Equipment Distribution assets $ 3,896.2 $ 1,221.5 $ 2,674.7 Electric generation assets (A) 4,155.9 1,493.3 2,662.6 Transmission assets (B) 2,548.8 481.3 2,067.5 Intangible plant 85.0 43.9 41.1 Other property and equipment 381.5 145.6 235.9 Total property, plant and equipment $ 11,067.4 $ 3,385.6 $ 7,681.8 (A) This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $45.3 million . (B) This amount includes a plant acquisition adjustment of $3.3 million and accumulated amortization of $0.6 million . |
Schedule of Change in Asset Retirement Obligation [Table Text Block] | The following table summarizes changes to OG&E's asset retirement obligations during the years ended December 31, 2017 and 2016 . (In millions) 2017 2016 Balance at January 1 $ 69.6 $ 63.3 Accretion expense 3.1 2.8 Revisions in estimated cash flows (A) 2.4 3.6 Liabilities settled — (0.1 ) Balance at December 31 $ 75.1 $ 69.6 (A) Assumptions changed related to the estimated timing of asbestos abatement and estimated cost of ash pond removal at two of OG&E's generating facilities. |
Related-Party Transactions Re25
Related-Party Transactions Related-Party Transactions (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Related Party Transaction [Line Items] | |
Schedule of Related Party Transactions [Table Text Block] | The following table summarizes related party transactions between OG&E and Enable during the years ended December 31, 2017 , 2016 and 2015 . Year Ended December 31 (In millions) 2017 2016 2015 Operating revenues: Electricity to power electric compression assets $ 14.0 $ 11.5 $ 13.8 Cost of sales: Natural gas transportation services $ 35.0 $ 35.0 $ 35.0 Natural gas purchases (sales) (2.1 ) 11.2 7.6 |
Fair Value Measurements (Tables
Fair Value Measurements (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Fair Value Disclosures [Abstract] | |
Fair Value, by Balance Sheet Grouping [Table Text Block] | The following table summarizes the fair value and carrying amount of OG&E's financial instruments at December 31, 2017 and 2016 . Year Ended December 31 (In millions) 2017 2016 Carrying Amount Fair Value Carrying Amount Fair Value Long-term Debt (including Long-term Debt due within one year): Senior Notes $ 2,854.3 $ 3,242.8 $ 2,385.5 $ 2,657.2 Industrial Authority Bonds 135.4 135.4 135.4 135.4 Tinker Debt 9.7 9.8 9.9 11.3 |
Stock-Based Compensation (Table
Stock-Based Compensation (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] | The following table summarizes OG&E's pre-tax compensation expense and related income tax benefit for the year s ended December 31, 2017 , 2016 and 2015 related to performance units and restricted stock for OG&E employees . Year Ended December 31 (In millions) 2017 2016 2015 Performance units: Total shareholder return $ 2.5 $ 2.1 $ 2.4 Earnings per share 0.5 0.1 0.4 Total performance units 3.0 2.2 2.8 Restricted stock — — 0.1 Net compensation expense $ 3.0 $ 2.2 $ 2.9 Income tax benefit $ 1.2 $ 0.9 $ 1.1 |
Performance Units Total Shareholder Return Valuation Assumptions [Table Text Block] | The number of performance units granted based on total shareholder return and the assumptions used to calculate the grant date fair value of the performance units based on total shareholder return are shown in the following table. 2017 2016 2015 Number of units granted to OG&E employees 85,501 105,076 90,098 Fair value of units granted $ 41.76 $ 20.84 $ 31.02 Expected dividend yield 3.8 % 3.5 % 2.6 % Expected price volatility 19.8 % 19.8 % 16.9 % Risk-free interest rate 1.46 % 0.88 % 0.91 % Expected life of units (in years) 2.86 2.85 2.85 |
Performance Units Earnings Per Share Valuation Assumptions [Table Text Block] | The number of performance units granted based on earnings per share and the grant date fair value are shown in the following table. 2017 2016 2015 Number of units granted to OG&E employees 28,499 35,025 30,034 Fair value of units granted $ 34.83 $ 26.59 $ 33.99 |
Share-based Compensation, Activity [Table Text Block] | A summary of the activity for OGE Energy's performance units and restricted stock applicable to OG&E's employees at December 31, 2017 and changes in 2017 are shown in the following table. Performance Units Total Shareholder Return Earnings Per Share Restricted Stock (Dollars in millions) Number Aggregate Intrinsic Value Number Aggregate Intrinsic Value Number Aggregate Intrinsic Value Units/shares outstanding at 12/31/16 236,581 78,864 1,796 Granted 85,501 (A) 28,499 (A) — Converted (57,484 ) (B) $ — (19,164 ) (B) $ — N/A Vested N/A N/A (1,796 ) $ 0.1 Forfeited (7,805 ) (2,602 ) — Employee migration (4,543 ) (C) (1,514 ) (C) 625 Units/shares outstanding at 12/31/17 252,250 $ 0.9 84,083 $ 2.5 625 $ — Units/shares fully vested at 12/31/17 73,092 $ — 24,366 $ 0.4 (A) For performance units, this represents the target number of performance units granted. Actual number of performance units earned, if any, is dependent upon performance and may range from zero percent to 200 percent of the target. (B) These amounts represent performance units that vested at December 31, 2016 which were settled in February 2017. (C) Due to certain employees transferring between OG&E and OGE Energy. |
Schedule of Nonvested Share Activity [Table Text Block] | A summary of the activity for OGE Energy's non-vested performance units and restricted stock applicable to OG&E's employees at December 31, 2017 and changes in 2017 are shown in the following table. Performance Units Total Shareholder Return Earnings Per Share Restricted Stock Number Weighted-Average Number Weighted-Average Number Weighted-Average Units/shares non-vested at 12/31/16 179,097 $ 25.12 59,700 $ 29.70 1,796 $ 35.45 Granted 85,501 (A) $ 41.76 28,499 (A) $ 34.83 — $ — Vested (73,092 ) $ 31.02 (24,366 ) $ 33.99 (1,796 ) $ 35.38 Forfeited (7,805 ) $ 31.52 (2,602 ) $ 31.20 — $ — Employee migration (4,543 ) (B) $ 29.84 (1,514 ) (B) $ 31.09 625 $ 31.92 Units/shares non-vested at 12/31/17 179,158 $ 30.26 59,717 $ 30.30 625 $ 31.92 Units/shares expected to vest 172,618 (C) 57,592 (C) 625 (A) For performance units, this represents the target number of performance units granted. Actual number of performance units earned, if any, is dependent upon performance and may range from zero percent to 200 percent of the target. (B) Due to certain employees transferring between OG&E and OGE Energy. (C) The intrinsic value of the performance units based on total shareholder return and earnings per share is $0.9 million and $2.0 million , respectively. |
Fair Value of Vested Performance Units and Restricted Stock [Table Text Block] | A summary of OG&E's fair value for its vested performance units and restricted stock is shown in the following table. Year Ended December 31 (In millions) 2017 2016 2015 Performance units: Total shareholder return $ 2.3 $ 2.0 $ 2.1 Earnings per share 0.4 — — Restricted stock 0.1 0.1 0.1 |
Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block] | A summary of OG&E's unrecognized compensation cost for its non-vested performance units and restricted stock and the weighted-average periods over which the compensation cost is expected to be recognized are shown in the following table. December 31, 2017 Unrecognized Compensation Cost (In millions) Weighted Average to be Recognized (In years) Performance units: Total shareholder return $ 2.9 1.77 Earnings per share 0.9 1.68 Total performance units 3.8 Restricted stock — 1.58 Total $ 3.8 |
Supplemental Cash Flow Inform28
Supplemental Cash Flow Information (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Supplemental Cash Flow Information [Abstract] | |
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] | The following table discloses information about investing and financing activities that affected recognized assets and liabilities but did not result in cash receipts or payments. Cash paid for interest, net of interest capitalized, and cash paid for income taxes, net of income tax refunds are also disclosed in the table. Year Ended December 31 (In millions) 2017 2016 2015 NON-CASH INVESTING AND FINANCING ACTIVITIES Power plant long-term service agreement $ 2.6 $ 39.5 $ 2.3 SUPPLEMENTAL CASH FLOW INFORMATION Cash paid during the period for: Interest (net of interest capitalized) (A) $ 133.1 $ 138.3 $ 143.6 Income taxes (net of income tax refunds) (71.5 ) — (6.2 ) (A) Net of interest capitalized of $18.0 million , $7.5 million and $4.2 million in 2017 , 2016 and 2015 , respectively. |
Income Taxes (Tables)
Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | |
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] | The items comprising income tax (benefit) expense are as follows: Year Ended December 31 (In millions) 2017 2016 2015 Provision (benefit) for current income taxes: Federal $ 26.3 $ 2.9 $ (17.5 ) State (4.3 ) (5.3 ) (5.3 ) Total provision (benefit) for current income taxes 22.0 (2.4 ) (22.8 ) Provision for deferred income taxes, net: Federal 100.0 99.8 117.0 State 19.9 17.2 11.3 Total provision for deferred income taxes, net 119.9 117.0 128.3 Deferred federal investment tax credits, net (0.1 ) (0.2 ) (0.7 ) Total income tax expense $ 141.8 $ 114.4 $ 104.8 |
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] | The following schedule reconciles the statutory tax rates to the effective income tax rate: Year Ended December 31 2017 2016 2015 Statutory federal tax rate 35.0 % 35.0 % 35.0 % State income taxes, net of federal income tax benefit 2.2 1.8 0.5 Amortization of net unfunded deferred taxes 0.9 0.8 0.9 Federal renewable energy credit (A) (6.1 ) (8.2 ) (8.8 ) Other (0.3 ) 0.1 (0.1 ) Uncertain tax positions — 0.1 0.7 Federal investment tax credits, net — (0.9 ) (0.2 ) Effective income tax rate 31.7 % 28.7 % 28.0 % (A) Represents credits associated with the production from OG&E's wind farms. |
Schedule of Deferred Tax Assets and Liabilities [Table Text Block] | The components of Deferred Income Taxes at December 31, 2017 and 2016 were as follows: December 31 (In millions) 2017 2016 Deferred income tax liabilities, net: Accelerated depreciation and other property related differences $ 1,449.6 $ 2,101.4 OG&E Pension Plan 28.4 48.0 Regulatory asset 18.9 34.4 Bond redemption-unamortized costs 2.6 4.3 Income taxes (recoverable from) refundable to customers, net (244.3 ) 24.1 Federal tax credits (218.3 ) (209.3 ) State tax credits (129.2 ) (102.6 ) Asset retirement obligations (19.2 ) (24.5 ) Postretirement medical and life insurance benefits (17.4 ) (34.3 ) Regulatory liabilities (16.8 ) (34.6 ) Net operating losses (11.2 ) (26.1 ) Other (4.8 ) (16.7 ) Accrued liabilities (3.8 ) (8.0 ) Accrued vacation (1.4 ) (2.4 ) Deferred federal investment tax credits (0.5 ) (0.8 ) Uncollectible accounts (0.4 ) (0.6 ) Total deferred income tax liabilities, net $ 832.2 $ 1,752.3 |
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] | Following is a reconciliation of OG&E’s total gross unrecognized tax benefits as of the years ended December 31, 2017 , 2016 and 2015 . (In millions) 2017 2016 2015 Balance at January 1 $ 20.7 $ 20.2 $ 16.1 Tax positions related to current year: Additions — 0.5 4.1 Balance at December 31 $ 20.7 $ 20.7 $ 20.2 |
Summary of Tax Credit Carryforwards [Table Text Block] | The following table summarizes these carry forwards: (In millions) Carry Forward Amount Deferred Tax Asset Earliest Expiration Date State operating loss $ 250.5 $ 11.2 2030 Federal tax credits 218.3 218.3 2029 State tax credits: Oklahoma investment tax credits 128.2 101.3 N/A Oklahoma capital investment board credits 8.5 8.5 N/A Oklahoma zero emission tax credits 24.1 19.4 2020 |
Long-Term Debt (Tables)
Long-Term Debt (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Long-term Debt, Unclassified [Abstract] | |
Schedule of Long-term Debt Instruments [Table Text Block] | OG&E has tax-exempt pollution control bonds with optional redemption provisions that allow the holders to request repayment of the bonds on any business day. The bonds, which can be tendered at the option of the holder during the next 12 months, are as follows: SERIES DATE DUE AMOUNT (In millions) 0.65% - 1.86% Garfield Industrial Authority, January 1, 2025 $ 47.0 0.65% - 1.80% Muskogee Industrial Authority, January 1, 2025 32.4 0.66% - 1.80% Muskogee Industrial Authority, June 1, 2027 56.0 Total (redeemable during next 12 months) $ 135.4 |
Retirement Plans and Postreti31
Retirement Plans and Postretirement Benefit Plans (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Defined Benefit Plan [Abstract] | |
Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block] | The following table presents the status of OGE Energy's Pension Plan, the Restoration of Retirement Income Plan and the postretirement benefit plans for 2017 and 2016 . These amounts have been recorded in Accrued Benefit Obligations with the offset recorded as a regulatory asset in OG&E's Balance Sheets as discussed in Note 1. The regulatory asset represents a net periodic benefit cost to be recognized in the Statements of Income in future periods. OG&E's portion of the benefit obligation for OGE Energy's Pension Plan and the Restoration of Retirement Income Plan represents the projected benefit obligation, while the benefit obligation for the postretirement benefit plans represents the accumulated postretirement benefit obligation. The accumulated postretirement benefit obligation for OG&E's Pension Plan and Restoration of Retirement Income Plan differs from the projected benefit obligation in that the former includes no assumption about future compensation levels. The accumulated postretirement benefit obligation for the Pension Plan and the Restoration of Retirement Income Plan at December 31, 2017 was $469.0 million and $3.9 million , respectively. The accumulated postretirement benefit obligation for the Pension Plan and the Restoration of Retirement Income Plan at December 31, 2016 was $458.1 million and $3.4 million , respectively. The details of the funded status of the Pension Plan, the Restoration of Retirement Income Plan and the postretirement benefit plans and the amounts included in the Balance Sheets are as follows: Pension Plan Restoration of Retirement Postretirement December 31 (In millions) 2017 2016 2017 2016 2017 2016 Change in benefit obligation Beginning obligations $ 500.5 $ 514.4 $ 4.0 $ 2.7 $ 166.4 $ 176.1 Service cost 10.1 10.3 0.1 0.1 0.4 0.6 Interest cost 19.5 19.2 0.2 0.1 5.6 7.4 Plan settlements (35.2 ) — — (1.0 ) (21.1 ) — Plan amendments — — — — (29.4 ) — Participants' contributions — — — — 2.7 2.9 Actuarial losses (gains) 28.8 1.2 0.1 2.1 4.6 (7.2 ) Benefits paid (13.1 ) (44.6 ) (0.2 ) — (13.4 ) (13.4 ) Ending obligations $ 510.6 $ 500.5 $ 4.2 $ 4.0 $ 115.8 $ 166.4 Change in plans' assets Beginning fair value $ 457.3 $ 464.2 $ — $ — $ 47.8 $ 50.0 Actual return on plans' assets 64.2 37.7 — — 2.5 1.8 Employer contributions 4.0 — 0.2 1.0 26.7 6.5 Plan settlements (35.2 ) — — (1.0 ) (21.1 ) — Participants' contributions — — — — 2.7 2.9 Benefits paid (13.1 ) (44.6 ) (0.2 ) — (13.4 ) (13.4 ) Ending fair value $ 477.2 $ 457.3 $ — $ — $ 45.2 $ 47.8 Funded status at end of year $ (33.4 ) $ (43.2 ) $ (4.2 ) $ (4.0 ) $ (70.6 ) $ (118.6 ) |
Schedule of Defined Benefit Plans Disclosures [Table Text Block] | Net Periodic Benefit Cost Pension Plan Restoration of Retirement Postretirement Benefit Plans Year Ended December 31 (In millions) 2017 2016 2015 2017 2016 2015 2017 2016 2015 Included in Other Operation and Maintenance: Service cost $ 10.1 $ 10.3 $ 10.3 $ 0.1 $ 0.1 $ 0.1 $ 0.4 $ 0.6 $ 1.0 Included in Other Net Periodic Pension and Postretirement (Cost) Benefit: Interest cost 19.5 19.2 19.8 0.2 0.1 0.1 5.6 7.4 7.9 Expected return on plan assets (32.8 ) (33.1 ) (36.5 ) — — — (2.0 ) (2.1 ) (2.2 ) Amortization of net loss 13.0 12.4 13.8 0.4 0.1 0.1 1.9 2.5 11.9 Amortization of unrecognized prior service cost (A) — — 0.5 — — — (2.5 ) (6.1 ) (13.6 ) Settlement 11.7 — 14.2 — 0.4 — 0.4 — — Net periodic benefit cost (B) $ 21.5 $ 8.8 $ 22.1 $ 0.7 $ 0.7 $ 0.3 $ 3.8 $ 2.3 $ 5.0 (A) Unamortized prior service cost is amortized on a straight-line basis over the average remaining service period to the first eligibility age of participants who are expected to receive a benefit and are active at the date of the plan amendment. (B) In addition to the $26.0 million , $11.8 million and $27.4 million of net periodic benefit cost recognized in 2017 , 2016 and 2015 , respectively, OG&E recognized the following: • a change in pension expense in 2017 , 2016 and 2015 of $(2.3) million , $9.9 million and $(3.1) million , respectively, to maintain the allowable amount to be recovered for pension expense in the Oklahoma jurisdiction, which are included in the Pension tracker regulatory asset or liability (see Note 1); • an increase in postretirement medical expense in 2017 , 2016 and 2015 of $6.2 million , $7.9 million and $5.8 million , respectively, to maintain the allowable amount to be recovered for postretirement medical expense in the Oklahoma jurisdiction which are included in the Pension tracker regulatory asset or liability (see Note 1); and • a deferral of pension expense in 2017, 2016 and 2015 of $0.9 million , $0.1 million and $1.9 million related to the Arkansas jurisdictional portion of the pension settlement charge of $11.7 million , $0.4 million and $14.2 million , respectively. |
Schedule of Capitalized Pension and Postretirement Cost [Table Text Block] | (In millions) 2017 2016 2015 Capitalized portion of net periodic pension benefit cost $ 3.4 $ 2.9 $ 2.6 Capitalized portion of net periodic postretirement benefit cost 1.1 0.8 1.6 |
Schedule of Assumptions Used [Table Text Block] | Rate Assumptions Pension Plan and Postretirement Year Ended December 31 2017 2016 2015 2017 2016 2015 Discount rate 3.60 % 4.00 % 4.00 % 3.70 % 4.20 % 4.25 % Rate of return on plans' assets 7.50 % 7.50 % 7.50 % 4.00 % 4.00 % 4.00 % Compensation increases 4.20 % 4.20 % 4.20 % N/A N/A N/A Assumed health care cost trend: Initial trend N/A N/A N/A 7.50 % 6.75 % 6.10 % Ultimate trend rate N/A N/A N/A 4.50 % 4.50 % 4.50 % Ultimate trend year N/A N/A N/A 2030 2026 2026 N/A - not applicable |
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block] | ONE-PERCENTAGE POINT INCREASE Year Ended December 31 (In millions) 2017 2016 2015 Effect on aggregate of the service and interest cost components $ — $ — $ — Effect on accumulated postretirement benefit obligations 0.1 0.1 0.1 ONE-PERCENTAGE POINT DECREASE Year Ended December 31 (In millions) 2017 2016 2015 Effect on aggregate of the service and interest cost components $ — $ — $ — Effect on accumulated postretirement benefit obligations 0.2 0.5 0.5 |
Projected Benefit Obligation Funded Status Thresholds [Table Text Block] | The Pension Plan assets are held in a trust which follows an investment policy and strategy designed to reduce the funded status volatility of the Plan by utilizing liability driven investing. The purpose of liability-driven investing is to structure the asset portfolio to more closely resemble the pension liability and thereby more effectively hedge against changes in the liability. The investment policy follows a glide path approach that shifts a higher portfolio weighting to fixed income as the Plan's funded status increases. The table below sets forth the targeted fixed income and equity allocations at different funded status levels. Projected Benefit Obligation Funded Status Thresholds <90% 95% 100% 105% 110% 115% 120% Fixed income 50% 58% 65% 73% 80% 85% 90% Equity 50% 42% 35% 27% 20% 15% 10% Total 100% 100% 100% 100% 100% 100% 100% |
Pension Plan Equity Asset Allocation Table [Table Text Block] | Within the portfolio's overall allocation to equities, the funds are allocated according to the guidelines in the table below. Asset Class Target Allocation Minimum Maximum Domestic Large Cap Equity 40% 35% 60% Domestic Mid-Cap Equity 15% 5% 25% Domestic Small-Cap Equity 25% 5% 30% International Equity 20% 10% 30% |
Schedule of Allocation of Plan Assets [Table Text Block] | The following tables summarize OG&E's portion of OGE Energy's Pension Plan's investments that are measured at fair value on a recurring basis at December 31, 2017 and 2016 . There were no Level 3 investments held by the Pension Plan at December 31, 2017 and 2016 . (In millions) December 31, 2017 Level 1 Level 2 Net Asset Value (A) Common stocks $ 225.9 $ 225.9 $ — $ — U.S. Treasury notes and bonds (B) 169.7 169.7 — — Mortgage- and asset-backed securities 43.4 — 43.4 — Corporate fixed income and other securities 153.8 — 153.8 — Commingled fund (C) 29.9 — — 29.9 Foreign government bonds 4.0 — 4.0 — U.S. municipal bonds 1.2 — 1.2 — Money market fund 4.3 — — 4.3 Mutual fund 7.8 7.8 — — Futures: U.S. Treasury futures (receivable) 13.4 — 13.4 — U.S. Treasury futures (payable) (11.4 ) — (11.4 ) — Cash collateral 0.3 0.3 — — Forward contracts: Receivable (foreign currency) 0.1 — 0.1 — Total Pension Plan investments $ 642.4 $ 403.7 $ 204.5 $ 34.2 Receivable from broker for securities sold — Interest and dividends receivable 3.2 Payable to broker for securities purchased (10.3 ) Pension Plan investments attributable to affiliates (158.1 ) Total Pension Plan assets $ 477.2 (In millions) December 31, 2016 Level 1 Level 2 Net Asset Value (A) Common stocks $ 237.1 $ 237.1 $ — $ — U.S. Treasury notes and bonds (B) 122.3 122.3 — — Mortgage-backed securities 59.2 — 59.2 — Corporate fixed income and other securities 137.6 — 137.6 — Commingled fund (C) 23.8 — — 23.8 Foreign government bonds 5.2 — 5.2 — U.S. municipal bonds 1.9 — 1.9 — Money market fund 2.2 — — 2.2 Mutual fund 9.0 9.0 — — Futures: U.S. Treasury futures (receivable) 10.7 — 10.7 — U.S. Treasury futures (payable) (2.3 ) — (2.3 ) — Cash collateral 0.3 0.3 — — Forward contracts: Receivable (foreign currency) 0.2 — 0.2 — Total Pension Plan investments $ 607.2 $ 368.7 $ 212.5 $ 26.0 Receivable from broker for securities sold — Interest and dividends receivable 3.0 Payable to broker for securities purchased (14.3 ) Pension Plan investments attributable to affiliates (138.6 ) Total Pension Plan assets $ 457.3 (A) GAAP allows the measurement of certain investments that do not have a readily determinable fair value at the net asset value. These investments do not consider the observability of inputs; therefore, they are not included within the fair value hierarchy. (B) This category represents U.S. Treasury notes and bonds with a Moody's Investors Services rating of Aaa and Government Agency Bonds with a Moody's Investors Services rating of A1 or higher. (C) This category represents units of participation in a commingled fund that primarily invested in stocks of international companies and emerging markets. The following tables summarize OG&E's portion of OGE Energy's postretirement benefit plans' investments that are measured at fair value on a recurring basis at December 31, 2017 and 2016 . There were no Level 2 investments held by the postretirement benefit plans at December 31, 2017 and 2016 . (In millions) December 31, 2017 Level 1 Level 3 Group retiree medical insurance contract $ 40.2 $ — $ 40.2 Mutual funds investment: U.S. equity investments 9.5 9.5 — Cash 0.5 0.5 — Total plan investments $ 50.2 $ 10.0 $ 40.2 Plan investments attributable to affiliates (5.0 ) Total plan assets $ 45.2 (In millions) December 31, 2016 Level 1 Level 3 Group retiree medical insurance contract $ 44.7 $ — $ 44.7 Mutual funds investment: U.S. equity investments 8.1 8.1 — Money market funds investment 0.3 0.3 — Total plan investments $ 53.1 $ 8.4 $ 44.7 Plan investments attributable to affiliates (5.3 ) Total plan assets $ 47.8 |
Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets [Table Text Block] | The following table summarizes the postretirement benefit plans' investments that are measured at fair value on a recurring basis using significant unobservable inputs (Level 3). Year Ended December 31 (In millions) 2017 Group retiree medical insurance contract: Beginning balance $ 44.7 Interest income 0.8 Dividend income 0.5 Net unrealized gains related to instruments held at the reporting date 0.3 Claims paid (5.9 ) Realized losses (0.1 ) Investment fees (0.1 ) Ending balance $ 40.2 |
Schedule of Expected Benefit Payments [Table Text Block] | The Medicare Prescription Drug, Improvement and Modernization Act of 2003 expanded coverage for prescription drugs. The following table summarizes the gross benefit payments OG&E expects to pay related to its postretirement benefit plans, including prescription drug benefits . (In millions) Gross Projected 2018 $ 9.3 2019 9.3 2020 9.4 2021 9.3 2022 9.3 After 2022 37.5 The following table summarizes the benefit payments OG&E expects to pay related to OGE Energy's Pension Plan and Restoration of Retirement Income Plan. These expected benefits are based on the same assumptions used to measure OGE Energy's benefit obligation at the end of the year and include benefits attributable to estimated future employee service. (In millions) Projected Benefit Payments 2018 $ 46.9 2019 47.3 2020 48.2 2021 46.7 2022 44.6 After 2022 206.4 |
Commitments and Contingencies (
Commitments and Contingencies (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Commitments and Contingencies Disclosure [Abstract] | |
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] | Operating Lease Obligations OG&E has operating lease obligations expiring at various dates , primarily for railcar leases and wind farm land leases . Future minimum payments for noncancellable operating leases are as follows: Year Ended December 31 (In millions) 2018 2019 2020 2021 2022 After 2022 Total Operating lease obligations: Railcars $ 1.7 $ 20.9 $ — $ — $ — $ — $ 22.6 Wind farm land leases 2.5 2.5 2.9 2.9 2.9 40.6 54.3 Total operating lease obligations $ 4.2 $ 23.4 $ 2.9 $ 2.9 $ 2.9 $ 40.6 $ 76.9 |
Unrecorded Unconditional Purchase Obligations Disclosure [Table Text Block] | Other Purchase Obligations and Commitments OG&E's other future purchase obligations and commitments estimated for the next five years are as follows: (In millions) 2018 2019 2020 2021 2022 Total Other purchase obligations and commitments: Cogeneration capacity and fixed operation and maintenance payments $ 72.8 $ 65.3 $ 53.2 $ 49.5 $ 45.4 $ 286.2 Expected cogeneration energy payments 35.7 35.6 35.9 37.1 38.3 182.6 Minimum fuel purchase commitments 139.8 36.2 24.6 24.6 24.6 249.8 Expected wind purchase commitments 58.7 56.5 56.9 57.3 57.8 287.2 Long-term service agreement commitments 7.9 41.9 2.4 2.4 2.4 57.0 Mustang Modernization expenditures 24.9 — — — — 24.9 Environmental compliance plan expenditures 63.0 8.9 0.2 — — 72.1 Total other purchase obligations and commitments $ 402.8 $ 244.4 $ 173.2 $ 170.9 $ 168.5 $ 1,159.8 |
Schedule of Wind Power Purchases [Table Text Block] | OG&E owns the 120 MW Centennial, 101 MW OU Spirit and 228 MW Crossroads wind farms. OG&E's current wind power portfolio also includes purchase power contracts with the following: Company Location Term of Contract Expiration of Contract MWs CPV Keenan Woodward County, OK 20 years 2030 152.0 Edison Mission Energy Dewey County, OK 20 years 2031 130.0 NextEra Energy Blackwell, OK 20 years 2032 60.0 FPL Energy Woodward, OK 15 years 2018 50.0 The following table summarizes OG&E's wind power purchases for the years ended December 31, 2017 , 2016 and 2015 . Year Ended December 31 (In millions) 2017 2016 2015 CPV Keenan $ 29.0 $ 29.2 $ 26.7 Edison Mission Energy 22.1 21.1 19.7 NextEra Energy 7.4 7.3 7.0 FPL Energy 2.6 3.4 3.2 Total wind power purchased $ 61.1 $ 61.0 $ 56.6 |
Quarterly Financial Data (Table
Quarterly Financial Data (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Quarterly Financial Data [Abstract] | |
Schedule of Quarterly Financial Information [Table Text Block] | Due to the seasonal fluctuations and other factors of OG&E's business, the operating results for interim periods are not necessarily indicative of the results that may be expected for the year. In OG&E's opinion, the following quarterly financial data includes all adjustments, consisting of normal recurring adjustments, necessary to fairly present such amounts. Summarized quarterly unaudited financial data is as follows: Quarter Ended ( In millions) March 31 June 30 September 30 December 31 Total Operating revenues 2017 $ 456.0 $ 586.4 $ 716.8 $ 501.9 $ 2,261.1 2016 $ 433.1 $ 551.4 $ 743.9 $ 530.8 $ 2,259.2 Operating income 2017 $ 45.6 $ 145.7 $ 243.6 $ 92.2 $ 527.1 2016 $ 38.8 $ 131.8 $ 257.3 $ 81.8 $ 509.7 Net income 2017 $ 16.2 $ 86.2 $ 161.5 $ 41.6 $ 305.5 2016 $ 6.1 $ 72.3 $ 159.9 $ 45.8 $ 284.1 |
Summary of Significant Accoun34
Summary of Significant Accounting Policies Regulated Operations (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 | |
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Fuel clause under recoveries | $ 0 | $ 51.3 | |
Fuel clause over recoveries | 1.7 | 0 | |
Regulatory Assets, Current | 40.8 | 121.8 | |
Regulatory Assets, Noncurrent | 283 | 404.8 | |
Regulatory Liability, Current | 3.9 | 12.3 | |
Regulatory Liability, Noncurrent | 1,283.4 | 299.7 | |
Other Regulatory Liabilities [Member] | |||
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Regulatory Liability, Current | [1] | 2.2 | 12.3 |
Regulatory Liability, Noncurrent | 7.2 | 1.4 | |
Accrued removal obligations [Member] | |||
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Regulatory Liability, Noncurrent | 288.4 | 262.8 | |
Pension tracker [Member] | |||
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Regulatory Liability, Noncurrent | 32.3 | 35.5 | |
Oklahoma demand program rider under recovery [Member] | |||
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Regulatory Assets, Current | [2] | 31.6 | 51 |
SPP cost tracker rider under recovery [Member] | |||
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Regulatory Assets, Current | [2] | 7.7 | 10 |
Other Regulatory Assets [Member] | |||
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Regulatory Assets, Current | [2] | 1.5 | 9.5 |
Regulatory Assets, Noncurrent | 18.5 | 17.6 | |
Benefit Obligations [Member] | |||
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Regulatory Assets, Noncurrent | 177.2 | 232.6 | |
Income taxes recoverable from customers, net [Member] | |||
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Regulatory Assets, Noncurrent | 0 | 62.3 | |
Smart Grid [Member] | |||
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Regulatory Assets, Noncurrent | 32.8 | 43.2 | |
Deferred storm expenses [Member] | |||
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Regulatory Assets, Noncurrent | 42.2 | 35.7 | |
Unamortized loss on reacquired debt [Member] | |||
Schedule of Regulatory Assets and Liabilities [Line Items] | |||
Regulatory Assets, Noncurrent | $ 12.3 | $ 13.4 | |
[1] | Included in Other Current Liabilities on the Balance Sheets. | ||
[2] | Included in Other Current Assets on the Balance Sheets. |
Summary of Significant Accoun35
Summary of Significant Accounting Policies Accounting Records (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 |
Regulatory Liability, Noncurrent | $ 1,283.4 | $ 299.7 |
Components of Benefit Obligation Regulatory Asset | 177.2 | 232.6 |
Deferred Storm and Property Reserve Deficiency, Current | 2.7 | |
Smart Grid Project [Member] | ||
Smart Grid Costs to be Recovered | 6.9 | |
Regulatory Asset [Member] | ||
Components of Net Periodic Benefit Costs to be Recognized in Next Fiscal Year | 10.4 | |
Pension Plans [Member] | Defined Benefit Plans Income Loss [Member] | ||
Components of Benefit Obligation Regulatory Asset | 172.4 | 199.9 |
Components of Net Periodic Benefit Costs to be Recognized in Next Fiscal Year | 12.5 | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Defined Benefit Plans Income Loss [Member] | ||
Components of Benefit Obligation Regulatory Asset | 33.6 | 32.7 |
Components of Net Periodic Benefit Costs to be Recognized in Next Fiscal Year | 4 | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Prior Service Cost [Member] | ||
Components of Benefit Obligation Regulatory Asset | (28.8) | 0 |
Components of Net Periodic Benefit Costs to be Recognized in Next Fiscal Year | (6.1) | |
Income taxes recoverable from customers, net [Member] | ||
Regulatory Liability, Noncurrent | $ 955.5 | $ 0 |
Summary of Significant Accoun36
Summary of Significant Accounting Policies Allowance for Uncollectible Accounts Receviable (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 |
Accounts receivable reserve | $ 1.5 | $ 1.5 |
Summary of Significant Accoun37
Summary of Significant Accounting Policies Fuel Inventories (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2014 |
Other | $ 48.6 | $ 78.3 | |
Fuel inventories | 84.3 | 79.8 | |
Other Liabilities, Noncurrent | 135.8 | 134.7 | |
Public Utilities, Inventory, Fuel [Member] | |||
Other | 2.8 | ||
Fuel inventories | $ 84.3 | $ 82.4 | |
Deferred Costs and Other Assets | $ 11 |
Summary of Significant Accoun38
Summary of Significant Accounting Policies Property, Plant and Equipment (Details) - USD ($) $ in Millions | 12 Months Ended | ||||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |||
Property, Plant and Equipment [Line Items] | |||||
Property, Plant and Equipment, Gross | $ 11,902.6 | $ 11,067.4 | |||
Accumulated Depreciation | 3,568.8 | 3,385.6 | |||
Property, Plant and Equipment, Net | 8,333.8 | 7,681.8 | |||
OG&E [Member] | |||||
Property, Plant and Equipment [Line Items] | |||||
Property, Plant and Equipment, Gross | 11,902.6 | 11,067.4 | |||
Accumulated Depreciation | 3,568.8 | 3,385.6 | |||
Property, Plant and Equipment, Net | 8,333.8 | 7,681.8 | |||
Capitalized Computer Software, Gross | 37.5 | 36.5 | |||
Capitalized Computer Software, Amortization | 8.8 | 8 | $ 6.9 | ||
Electric Distribution [Member] | OG&E [Member] | |||||
Property, Plant and Equipment [Line Items] | |||||
Property, Plant and Equipment, Gross | 4,057.1 | 3,896.2 | |||
Accumulated Depreciation | 1,259.1 | 1,221.5 | |||
Property, Plant and Equipment, Net | 2,798 | 2,674.7 | |||
Electric Generation Equipment [Member] | OG&E [Member] | |||||
Property, Plant and Equipment [Line Items] | |||||
Property, Plant and Equipment, Gross | 4,475 | [1] | 4,155.9 | [2] | |
Accumulated Depreciation | 1,493.5 | [1] | 1,493.3 | [2] | |
Property, Plant and Equipment, Net | 2,981.5 | [1] | 2,662.6 | [2] | |
Amount of Acquisition Adjustments | 148.3 | 148.3 | |||
Public Utilities, Property, Plant and Equipment, Amount of Acquisition Adjustments, Related Accumulated Depreciation | 50.8 | 45.3 | |||
Electric Transmission [Member] | OG&E [Member] | |||||
Property, Plant and Equipment [Line Items] | |||||
Property, Plant and Equipment, Gross | 2,767.7 | [3] | 2,548.8 | [4] | |
Accumulated Depreciation | 506.5 | [3] | 481.3 | [4] | |
Property, Plant and Equipment, Net | 2,261.2 | [3] | 2,067.5 | [4] | |
Amount of Acquisition Adjustments | 3.3 | 3.3 | |||
Amount of Acquistion Adjustments Related Accumulated Amortization | 0.6 | 0.6 | |||
Finite-Lived Intangible Assets, Major Class Name [Domain] | OG&E [Member] | |||||
Property, Plant and Equipment [Line Items] | |||||
Property, Plant and Equipment, Gross | 181.8 | 85 | |||
Accumulated Depreciation | 135.8 | 43.9 | |||
Property, Plant and Equipment, Net | 46 | 41.1 | |||
Property, Plant and Equipment, Other Types [Member] | OG&E [Member] | |||||
Property, Plant and Equipment [Line Items] | |||||
Property, Plant and Equipment, Gross | 421 | 381.5 | |||
Accumulated Depreciation | 173.9 | 145.6 | |||
Property, Plant and Equipment, Net | $ 247.1 | $ 235.9 | |||
McClain Plant [Member] | |||||
Property, Plant and Equipment [Line Items] | |||||
Jointly Owned Utility Plant, Proportionate Ownership Share | 77.00% | [5] | 77.00% | [6] | |
Property, Plant and Equipment, Gross | $ 226.8 | [5] | $ 234.2 | [6] | |
Accumulated Depreciation | 71.4 | [5] | 72.3 | [6] | |
Property, Plant and Equipment, Net | 155.4 | [5] | 161.9 | [6] | |
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress | $ 0.4 | $ 0.2 | |||
Redbud Plant [Member] | |||||
Property, Plant and Equipment [Line Items] | |||||
Jointly Owned Utility Plant, Proportionate Ownership Share | 51.00% | [5],[7] | 51.00% | [6],[8] | |
Property, Plant and Equipment, Gross | $ 496.6 | [5],[7] | $ 489 | [6],[8] | |
Accumulated Depreciation | 136 | [5],[7] | 121 | [6],[8] | |
Property, Plant and Equipment, Net | 360.6 | [5],[7] | 368 | [6],[8] | |
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress | 7.8 | 1.8 | |||
Amount of Acquisition Adjustments | 148.3 | 148.3 | |||
Public Utilities, Property, Plant and Equipment, Amount of Acquisition Adjustments, Related Accumulated Depreciation | $ 50.8 | $ 45.3 | |||
[1] | This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $50.8 million. | ||||
[2] | This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $45.3 million | ||||
[3] | This amount includes a plant acquisition adjustment of $3.3 million and accumulated amortization of $0.6 million | ||||
[4] | This amount includes a plant acquisition adjustment of $3.3 million and accumulated amortization of $0.6 million. | ||||
[5] | Construction work in progress was $0.4 million and $7.8 million for the McClain and Redbud Plants, respectively. | ||||
[6] | Construction work in progress was $0.2 million and $1.8 million for the McClain and Redbud Plants, respectively. | ||||
[7] | This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $50.8 million. | ||||
[8] | This amount includes a plant acquisition adjustment of $148.3 million and accumulated amortization of $45.3 million. |
Summary of Significant Accoun39
Summary of Significant Accounting Policies Depreciation and Amortization (Details) - USD ($) $ in Millions | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Provision for Depreciation Rate | 2.50% | 3.00% |
Projected Provision for Depreciation in Next Fiscal Year | 2.70% | |
Percent Of Intangible Plant Balance Amortizable | 98.60% | |
Percent of Intangible Plant Balance Amortizable Thereafter | 1.40% | |
Transmission Equipment [Member] | OG&E [Member] | ||
Amount of Acquisition Adjustments | $ 3.3 | |
Redbud Plant [Member] | ||
Amount of Acquisition Adjustments | $ 148.3 | $ 148.3 |
Summary of Significant Accoun40
Summary of Significant Accounting Policies Asset Retirement Obligations (Details) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | ||
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | |||
Balance at January 1 | $ 69.6 | $ 63.3 | |
Accretion expense | 3.1 | 2.8 | |
Revisions in estimated cash flows | [1] | 2.4 | 3.6 |
Liabilities settled | 0 | (0.1) | |
Balance at December 31 | $ 75.1 | $ 69.6 | |
[1] | Assumptions changed related to the estimated timing of asbestos abatement and estimated cost of ash pond removal at two of OG&E's generating facilities. |
Summary of Significant Accoun41
Summary of Significant Accounting Policies Allowance for Funds Used During Construction (Details) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Public Utilities, Allowance for Funds Used During Construction, Rate | 8.20% | 8.20% | 8.10% |
Summary of Significant Accoun42
Summary of Significant Accounting Policies Environmental Costs (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 |
Site Contingency [Line Items] | ||
Accrued Environmental Loss Contingencies, Noncurrent | $ 17.1 | $ 13.9 |
Related-Party Transactions Re43
Related-Party Transactions Related-Party Transactions (Details) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Related Party Transaction [Line Items] | |||
Dividends, Common Stock | $ 105 | $ 190 | $ 120 |
Operating Costs Charged [Member] | OG&E [Member] | |||
Related Party Transaction [Line Items] | |||
Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party | 134.4 | 131.5 | 123 |
OG&E [Member] | Enable Midstream Partners [Member] | |||
Related Party Transaction [Line Items] | |||
Revenue from Related Parties | 14 | 11.5 | 13.8 |
OG&E [Member] | Natural Gas Transportation [Member] | Enable Midstream Partners [Member] | |||
Related Party Transaction [Line Items] | |||
Related Party Transaction, Purchases from Related Party | 35 | 35 | 35 |
OG&E [Member] | Natural Gas Purchases [Member] | Enable Midstream Partners [Member] | |||
Related Party Transaction [Line Items] | |||
Related Party Transaction, Purchases from Related Party | (2.1) | 11.2 | 7.6 |
Retained Earnings [Member] | |||
Related Party Transaction [Line Items] | |||
Dividends, Common Stock | $ 105 | $ 190 | $ 120 |
Fair Value Measurements (Detail
Fair Value Measurements (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
Long-term Debt, Carrying Amount | $ 2,999.4 | $ 2,530.8 |
OG&E Senior Notes [Member] | ||
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
Long-term Debt, Carrying Amount | 2,854.3 | 2,385.5 |
Long-term Debt, Fair Value | 3,242.8 | 2,657.2 |
OG&E Industrial Authority Bonds [Member] | ||
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
Long-term Debt, Carrying Amount | 135.4 | 135.4 |
Long-term Debt, Fair Value | 135.4 | 135.4 |
OG&E Tinker Debt [Member] | ||
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
Long-term Debt, Carrying Amount | 9.7 | 9.9 |
Long-term Debt, Fair Value | 9.8 | 11.3 |
Fair Value, Measurements, Recurring [Member] | ||
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
Derivative Assets (Liabilities), at Fair Value, Net | $ 0 | $ 0 |
Stock-Based Compensation (Detai
Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended | ||||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Number of Shares Authorized | 7,400,000 | ||||
Tax Benefit from Compensation Expense | $ 1.2 | $ 0.9 | $ 1.1 | ||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward] | |||||
Minimum payout range | 0.00% | ||||
Maximum payout range | 200.00% | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] | |||||
Total Compensation Cost Not yet Recognized | $ 3.8 | ||||
Total Shareholder Return [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ 41.76 | $ 20.84 | $ 31.02 | ||
Expected Dividend Rate | 3.80% | 3.50% | 2.60% | ||
Expected Volatility Rate | 19.80% | 19.80% | 16.90% | ||
Risk Free Interest Rate | 1.46% | 0.88% | 0.91% | ||
Expected Term | 2 years 10 months 10 days | 2 years 10 months 6 days | 2 years 10 months 6 days | ||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward] | |||||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number | 252,250 | 236,581 | |||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted | 85,501 | [1] | 105,076 | 90,098 | |
Equity Instruments Other than Options, Converted in Period | [2] | (57,484) | |||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period | (7,805) | ||||
Equity Other Than Options, Employee Migration | [3],[4] | (4,543) | |||
Awards Other than Options, Fully Vested, Outstanding | 73,092 | ||||
Equity Instruments Other than Options, Converted, Aggregrate Intrinsic Value | $ 0 | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding | 0.9 | ||||
Equity Instruments Other than Options, Fully Vested, Aggregrate Intrinsic Value | $ 0 | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] | |||||
Equity Instruments Other than Options, Nonvested, Beginning Balance | 179,097 | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted | 85,501 | [1] | 105,076 | 90,098 | |
Equity Instruments Other than Options, Vested in Period | (73,092) | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period | (7,805) | ||||
Equity Other Than Options, Employee Migration | [3],[4] | (4,543) | |||
Equity Instruments Other than Options, Nonvested, Ending Balance | 179,158 | 179,097 | |||
Awards Other than Options, Vested and Expected to Vest | [5] | 172,618 | |||
Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value | $ 30.26 | $ 25.12 | |||
Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | 41.76 | $ 20.84 | $ 31.02 | ||
Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value | 31.02 | ||||
Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value | 31.52 | ||||
Equity Other Than Options, Employee Migration, Weighted Average Grant Date Fair Value | $ 29.84 | ||||
Equity Instruments Other than Options, Expected to Vest, Intrinsic Value | $ 0 | ||||
Fair Value of Vested Performance Units and Restricted Stock | 2.3 | $ 2 | $ 2.1 | ||
Total Compensation Cost Not yet Recognized | $ 2.9 | ||||
Total Compensation Cost Not yet Recognized, Period for Recognition | 1 year 9 months 7 days | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested | $ 0.9 | ||||
Performance Units Related to Earnings Per Share [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ 34.83 | $ 26.59 | $ 33.99 | ||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward] | |||||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number | 84,083 | 78,864 | |||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted | 28,499 | [1] | 35,025 | 30,034 | |
Equity Instruments Other than Options, Converted in Period | [2] | (19,164) | |||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period | (2,602) | ||||
Equity Other Than Options, Employee Migration | [3],[4] | (1,514) | |||
Awards Other than Options, Fully Vested, Outstanding | 24,366 | ||||
Equity Instruments Other than Options, Converted, Aggregrate Intrinsic Value | $ 0 | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding | 2.5 | ||||
Equity Instruments Other than Options, Fully Vested, Aggregrate Intrinsic Value | $ 0.4 | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] | |||||
Equity Instruments Other than Options, Nonvested, Beginning Balance | 59,700 | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted | 28,499 | [1] | 35,025 | 30,034 | |
Equity Instruments Other than Options, Vested in Period | (24,366) | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period | (2,602) | ||||
Equity Other Than Options, Employee Migration | [3],[4] | (1,514) | |||
Equity Instruments Other than Options, Nonvested, Ending Balance | 59,717 | 59,700 | |||
Awards Other than Options, Vested and Expected to Vest | [5] | 57,592 | |||
Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value | $ 30.30 | $ 29.70 | |||
Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | 34.83 | $ 26.59 | $ 33.99 | ||
Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value | 33.99 | ||||
Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value | 31.20 | ||||
Equity Other Than Options, Employee Migration, Weighted Average Grant Date Fair Value | $ 31.09 | ||||
Equity Instruments Other than Options, Expected to Vest, Intrinsic Value | $ 0 | ||||
Fair Value of Vested Performance Units and Restricted Stock | 0.4 | $ 0 | $ 0 | ||
Total Compensation Cost Not yet Recognized | $ 0.9 | ||||
Total Compensation Cost Not yet Recognized, Period for Recognition | 1 year 8 months 5 days | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested | $ 2 | ||||
Performance Shares [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Compensation expense | 3 | 2.2 | 2.8 | ||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] | |||||
Total Compensation Cost Not yet Recognized | 3.8 | ||||
Restricted Stock [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Compensation expense | $ 0 | $ 0 | 0.1 | ||
Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ 0 | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward] | |||||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number | 625 | 1,796 | |||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted | 0 | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period | 0 | ||||
Equity Other Than Options, Employee Migration | 625 | ||||
Equity Instruments Other than Options, Vested in Period, Aggregate Intrinsic Value | $ 0.1 | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding | $ 0 | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] | |||||
Equity Instruments Other than Options, Nonvested, Beginning Balance | 1,796 | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted | 0 | ||||
Equity Instruments Other than Options, Vested in Period | (1,796) | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period | 0 | ||||
Equity Other Than Options, Employee Migration | 625 | ||||
Equity Instruments Other than Options, Nonvested, Ending Balance | 625 | 1,796 | |||
Awards Other than Options, Vested and Expected to Vest | 625 | ||||
Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value | $ 31.92 | $ 35.45 | |||
Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | 0 | ||||
Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value | 35.38 | ||||
Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value | 0 | ||||
Equity Other Than Options, Employee Migration, Weighted Average Grant Date Fair Value | $ 31.92 | ||||
Fair Value of Vested Performance Units and Restricted Stock | $ 0.1 | $ 0.1 | 0.1 | ||
Total Compensation Cost Not yet Recognized | $ 0 | ||||
Total Compensation Cost Not yet Recognized, Period for Recognition | 1 year 6 months 29 days | ||||
Stock Compensation Plan [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Compensation expense | $ 3 | 2.2 | 2.9 | ||
Performance Units Related to Earnings Per Share [Member] | Performance Shares [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Compensation expense | 0.5 | 0.1 | 0.4 | ||
Total Shareholder Return [Member] | Performance Shares [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Compensation expense | $ 2.5 | $ 2.1 | $ 2.4 | ||
Common Stock | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures | 965 | 1,131 | 18,820 | ||
Restricted Stock [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Shares Paid for Tax Withholding | 146 | ||||
[1] | For performance units, this represents the target number of performance units granted. Actual number of performance units earned, if any, is dependent upon performance and may range from zero percent to 200 percent of the target. | ||||
[2] | These amounts represent performance units that vested at December 31, 2016 which were settled in February 2017. | ||||
[3] | Due to certain employees transferring between OG&E and OGE Energy. | ||||
[4] | Due to certain employees transferring between OG&E and OGE Energy. | ||||
[5] | The intrinsic value of the performance units based on total shareholder return and earnings per share is $0.9 million and $2.0 million, respectively. |
Supplemental Cash Flow Inform46
Supplemental Cash Flow Information (Details) - USD ($) $ in Millions | 12 Months Ended | |||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | ||
NON-CASH INVESTING AND FINANCING ACTIVITIES | ||||
Power plant long-term service agreement | $ 2.6 | $ 39.5 | $ 2.3 | |
SUPPLEMENTAL CASH FLOW INFORMATION | ||||
Interest (net of interest capitalized) | [1] | 133.1 | 138.3 | 143.6 |
Income taxes (net of income tax refunds) | (71.5) | 0 | (6.2) | |
Interest costs capitalized | $ 18 | $ 7.5 | $ 4.2 | |
[1] | Net of interest capitalized of $18.0 million, $7.5 million and $4.2 million in 2017, 2016 and 2015, respectively. |
Income Taxes (Details)
Income Taxes (Details) - USD ($) $ in Millions | 12 Months Ended | ||||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | ||
Increased Regulatory Liabilities due to Income Taxes | $ 1,038 | ||||
Current Federal Tax Expense (Benefit) | 26.3 | $ 2.9 | $ (17.5) | ||
Current State and Local Tax Expense (Benefit) | (4.3) | (5.3) | (5.3) | ||
Current Income Tax Expense (Benefit) | 22 | (2.4) | (22.8) | ||
Deferred Federal Income Tax Expense (Benefit) | 100 | 99.8 | 117 | ||
Deferred State and Local Income Tax Expense (Benefit) | 19.9 | 17.2 | 11.3 | ||
Deferred Income Tax Expense (Benefit) | 119.9 | 117 | 128.3 | ||
Investment Tax Credit | (0.1) | (0.2) | (0.7) | ||
Income Tax Expense (Benefit) | $ 141.8 | $ 114.4 | $ 104.8 | ||
Statutory federal tax rate | 35.00% | 35.00% | 35.00% | ||
Amortization of net unfunded deferred taxes | 0.90% | 0.80% | 0.90% | ||
Federal investment tax credits, net | 0.00% | (0.90%) | (0.20%) | ||
State income taxes, net of Federal income tax benefit | 2.20% | 1.80% | 0.50% | ||
Federal renewable energy credit | [1] | (6.10%) | (8.20%) | (8.80%) | |
Uncertain tax positions | 0.00% | 0.10% | 0.70% | ||
Other | (0.30%) | 0.10% | (0.10%) | ||
Effective income tax rate | 31.70% | 28.70% | 28.00% | ||
Accelerated depreciation and other property related differences | $ 1,449.6 | $ 2,101.4 | |||
OG&E Pension Plan | 28.4 | 48 | |||
Regulatory asset | 18.9 | 34.4 | |||
Income taxes (recoverable from) refundable to customers, net | (244.3) | 24.1 | |||
Bond redemption-unamortized costs | 2.6 | 4.3 | |||
Federal tax credits | (218.3) | (209.3) | |||
State tax credits | (129.2) | (102.6) | |||
Postretirement medical and life insurance benefits | (17.4) | (34.3) | |||
Regulatory liabilities | (16.8) | (34.6) | |||
Asset retirement obligations | (19.2) | (24.5) | |||
Net operating losses | (11.2) | (26.1) | |||
Other | (4.8) | (16.7) | |||
Accrued liabilities | (3.8) | (8) | |||
Accrued vacation | (1.4) | (2.4) | |||
Deferred federal investment tax credits | (0.5) | (0.8) | |||
Uncollectible accounts | (0.4) | 0.6 | |||
Total deferred income tax liabilities, net | 832.2 | 1,752.3 | |||
Unrecognized Tax Benefits | 20.7 | 20.7 | $ 20.2 | $ 16.1 | |
Current year additions | 0 | 0.5 | 4.1 | ||
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued | 0 | ||||
Tax Credit Carryforward, Deferred Tax Asset | 218.3 | 209.3 | |||
State operating loss [Member] | |||||
Operating Loss Carryforwards | 250.5 | ||||
Deferred Tax Assets, Operating Loss Carryforwards, State and Local | $ 11.2 | ||||
Tax Credit Carryforward, Expiration Date | Dec. 31, 2030 | ||||
Federal tax credits [Member] | |||||
Federal tax credits | $ (218.3) | ||||
Tax Credit Carryforward, Amount | 218.3 | ||||
Tax Credit Carryforward, Deferred Tax Asset | $ 218.3 | ||||
Tax Credit Carryforward, Expiration Date | Dec. 31, 2029 | ||||
Oklahoma investment tax credits [Member] | |||||
Federal tax credits | $ (101.3) | ||||
Tax Credit Carryforward, Amount | 128.2 | ||||
Tax Credit Carryforward, Deferred Tax Asset | 101.3 | ||||
Oklahoma capital investment board credits [Member] | |||||
Federal tax credits | (8.5) | ||||
Tax Credit Carryforward, Amount | 8.5 | ||||
Tax Credit Carryforward, Deferred Tax Asset | 8.5 | ||||
Oklahoma zero emission tax credits [Member] | |||||
Federal tax credits | (19.4) | ||||
Tax Credit Carryforward, Amount | 24.1 | ||||
Tax Credit Carryforward, Deferred Tax Asset | $ 19.4 | ||||
Tax Credit Carryforward, Expiration Date | Dec. 31, 2020 | ||||
OG&E [Member] | |||||
Unrecognized Tax Benefits that Would Impact Effective Tax Rate | $ 16.4 | $ 13.5 | $ 13.2 | ||
[1] | Represents credits associated with the production from OG&E's wind farms. |
Common Stock and Cumulative P48
Common Stock and Cumulative Preferred Stock (Details) - shares | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Stock Issued During Period, Shares, New Issues | 0 | 0 | 0 |
Long-Term Debt (Details)
Long-Term Debt (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended | ||
Sep. 30, 2017 | Dec. 31, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | |
Debt Instrument [Line Items] | ||||
Total long-term debt | $ 2,999.4 | $ 2,530.8 | ||
Percent of Principal Amount Subject to Optional Tender | 100.00% | |||
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months | $ 250.1 | |||
Long-term Debt, Maturities, Repayments of Principal in Year Two | 250.1 | |||
Long-term Debt, Maturities, Repayments of Principal in Year Three | 0.1 | |||
Long-term Debt, Maturities, Repayments of Principal in Year Four | 0.1 | |||
Long-term Debt, Maturities, Repayments of Principal in Year Five | $ 0.1 | |||
Garfield Industrial Authority Bond, Due January 1, 2025 [Member] | ||||
Debt Instrument [Line Items] | ||||
Date Due | Jan. 1, 2025 | |||
Muskogee Industrial Authority Bond, Due January 1, 2025 [Member] | ||||
Debt Instrument [Line Items] | ||||
Date Due | Jan. 1, 2025 | |||
Muskogee Industrial Authority Bond, Due June 1, 2027 [Member] | ||||
Debt Instrument [Line Items] | ||||
Date Due | Jun. 1, 2027 | |||
Redeemable during the next 12 months [Member] | ||||
Debt Instrument [Line Items] | ||||
Total long-term debt | $ 135.4 | |||
OG&E [Member] | Redeemable during the next 12 months [Member] | Garfield Industrial Authority Bond, Due January 1, 2025 [Member] | ||||
Debt Instrument [Line Items] | ||||
Long term debt, gross | 47 | 47 | ||
OG&E [Member] | Redeemable during the next 12 months [Member] | Muskogee Industrial Authority Bond, Due January 1, 2025 [Member] | ||||
Debt Instrument [Line Items] | ||||
Long term debt, gross | 32.4 | 32.4 | ||
OG&E [Member] | Redeemable during the next 12 months [Member] | Muskogee Industrial Authority Bond, Due June 1, 2027 [Member] | ||||
Debt Instrument [Line Items] | ||||
Long term debt, gross | 56 | 56 | ||
Senior Notes [Member] | OG&E [Member] | Series due April 1, 2047 [Member] | ||||
Debt Instrument [Line Items] | ||||
Long term debt, gross | $ 300 | $ 300 | 0 | |
Debt Instrument, Interest Rate, Stated Percentage | 4.15% | |||
Date Due | Apr. 1, 2047 | |||
Senior Notes [Member] | OG&E [Member] | Series Due July 15, 2017 [Member] | ||||
Debt Instrument [Line Items] | ||||
Long term debt, gross | $ 125 | $ 0 | 125 | |
Debt Instrument, Interest Rate, Stated Percentage | 6.50% | 6.50% | ||
Date Due | Jul. 15, 2017 | Jul. 15, 2017 | ||
Senior Notes [Member] | OG&E [Member] | Series due August 15, 2047 [Member] [Domain] | ||||
Debt Instrument [Line Items] | ||||
Long term debt, gross | $ 300 | $ 0 | ||
Debt Instrument, Interest Rate, Stated Percentage | 3.85% | |||
Date Due | Aug. 15, 2047 | |||
Minimum [Member] | Redeemable during the next 12 months [Member] | Garfield Industrial Authority Bond, Due January 1, 2025 [Member] | ||||
Debt Instrument [Line Items] | ||||
Debt Instrument, Interest Rate, Stated Percentage | 0.65% | |||
Minimum [Member] | Redeemable during the next 12 months [Member] | Muskogee Industrial Authority Bond, Due January 1, 2025 [Member] | ||||
Debt Instrument [Line Items] | ||||
Debt Instrument, Interest Rate, Stated Percentage | 0.65% | |||
Minimum [Member] | Redeemable during the next 12 months [Member] | Muskogee Industrial Authority Bond, Due June 1, 2027 [Member] | ||||
Debt Instrument [Line Items] | ||||
Debt Instrument, Interest Rate, Stated Percentage | 0.66% | |||
Maximum [Member] | Redeemable during the next 12 months [Member] | Garfield Industrial Authority Bond, Due January 1, 2025 [Member] | ||||
Debt Instrument [Line Items] | ||||
Debt Instrument, Interest Rate, Stated Percentage | 1.86% | |||
Maximum [Member] | Redeemable during the next 12 months [Member] | Muskogee Industrial Authority Bond, Due January 1, 2025 [Member] | ||||
Debt Instrument [Line Items] | ||||
Debt Instrument, Interest Rate, Stated Percentage | 1.80% | |||
Maximum [Member] | Redeemable during the next 12 months [Member] | Muskogee Industrial Authority Bond, Due June 1, 2027 [Member] | ||||
Debt Instrument [Line Items] | ||||
Debt Instrument, Interest Rate, Stated Percentage | 1.80% |
Short-Term Debt and Credit Fa50
Short-Term Debt and Credit Facility Short-Term Debt and Credit Facility (Details) - USD ($) | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Line of Credit Facility [Line Items] | ||
Line of Credit Facility, Expiration Date | Mar. 8, 2022 | |
Advances from parent | $ 0 | $ 49,900,000 |
Advances to parent | 112,500,000 | $ 0 |
Outstanding Intercompany Borrowings | $ 0 | |
Ratio of Consolidated Debt to Consolidated Capitalization | 65.00% | |
OG&E [Member] | ||
Line of Credit Facility [Line Items] | ||
Line of Credit Facility, Current Borrowing Capacity | $ 450,000,000 | |
Debt Restriction Maximum Letters of Credit | 100,000,000 | |
Available Optional Increase of Borrowing Capacity in Credit Facility | 150,000,000 | |
Intercompany Borrowings, Maximum Borrowing Capacity | $ 350,000,000 | |
Intercompany Borrowing Agreement, Expiration Date | Mar. 8, 2022 | |
Line of Credit Facility, Maximum Borrowing Capacity | $ 600,000,000 | |
Letters of Credit Outstanding, Amount | $ 300,000 | |
Short-term Debt, Weighted Average Interest Rate, at Point in Time | 0.95% | |
Commercial Paper | $ 0 | |
Short Term Borrowing Capacity That Has Regulatory Approval | $ 800,000,000 | |
Period For Which Regulatory Approval Has Been Given to Acquire Short Term Debt | 2 years | |
Acceleration of Debt [Member] | OG&E [Member] | ||
Line of Credit Facility [Line Items] | ||
Acceleration of Indebtedness of Credit Facility | $ 100,000,000 | |
Uninsured Judgements [Member] | OG&E [Member] | ||
Line of Credit Facility [Line Items] | ||
Acceleration of Indebtedness of Credit Facility | $ 100,000,000 |
Retirement Plans and Postreti51
Retirement Plans and Postretirement Benefit Plans (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended | |||||||
Dec. 31, 2017 | Sep. 30, 2017 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | ||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment | $ 42.9 | |||||||||
Defined Contribution Plan, Employer Matching Contribution, Percent of Match | 200.00% | |||||||||
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay | 5.00% | |||||||||
Payment for Pension Benefits | $ 20 | $ 20 | ||||||||
Settlement | $ (11.7) | $ (14.2) | ||||||||
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] | ||||||||||
Plan settlements | (27.9) | |||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Plan settlements | (27.9) | |||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Settlement | (11.7) | (14.2) | ||||||||
Net Periodic Benefit Cost | 26 | 11.8 | 27.4 | |||||||
Effect of One Percentage Point Increase on Service and Interest Cost Components | 0 | 0 | 0 | |||||||
Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation | 0.1 | 0.1 | 0.1 | |||||||
Effect of One Percentage Point Decrease on Service and Interest Cost Components | 0 | 0 | 0 | |||||||
Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation | 0.2 | 0.5 | 0.5 | |||||||
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months | $ 46.9 | |||||||||
Defined Benefit Plan, Expected Future Benefit Payment, Year Two | 47.3 | |||||||||
Defined Benefit Plan, Expected Future Benefit Payment, Year Three | 48.2 | |||||||||
Defined Benefit Plan, Expected Future Benefit Payment, Year Four | 46.7 | |||||||||
Defined Benefit Plan, Expected Future Benefit Payment, Year Five | 44.6 | |||||||||
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter | 206.4 | |||||||||
Defined Contribution Plan, Cost | 9.7 | 8.8 | 8.2 | |||||||
OKLAHOMA | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Settlement | (10.8) | (12.5) | ||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Settlement | (10.8) | (12.5) | ||||||||
Postretirement Benefit Plan [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment | (29.4) | 0 | ||||||||
Restoration of Retirement Income Plan [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant | 0 | 0 | ||||||||
Defined Benefit Plan, Plan Assets, Benefits Paid | (0.2) | 0 | ||||||||
Defined Benefit Plan, Benefit Obligation, Benefits Paid | (0.2) | 0 | ||||||||
Settlement | 0 | 0.4 | 0 | |||||||
Accumulated Benefit Obligation | 3.9 | $ 3.4 | ||||||||
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] | ||||||||||
Benefit Obligation, Beginning | 4 | 4 | 2.7 | |||||||
Service cost | 0.1 | 0.1 | 0.1 | |||||||
Interest cost | 0.2 | 0.1 | 0.1 | |||||||
Plan settlements | 0 | 1 | ||||||||
Participants' contributions | 0 | 0 | ||||||||
Actuarial gains (losses) | 0.1 | 2.1 | ||||||||
Benefit Obligation, Ending | 4.2 | 4.2 | 4 | 2.7 | ||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | 0 | |||||||
Actual return on plans' assets | 0 | 0 | ||||||||
Employer contributions | 0.2 | 1 | ||||||||
Plan settlements | 0 | 1 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | 0 | ||||||
Funded Status of Plan | (4.2) | (4) | ||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Service cost | 0.1 | 0.1 | 0.1 | |||||||
Interest cost | 0.2 | 0.1 | 0.1 | |||||||
Expected return on plan assets | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Amortization of Gain (Loss) | (0.4) | (0.1) | (0.1) | |||||||
Amortization of unrecognized prior service cost | [1] | 0 | 0 | 0 | ||||||
Settlement | 0 | 0.4 | 0 | |||||||
Net Periodic Benefit Cost | [2] | 0.7 | 0.7 | 0.3 | ||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | 0 | $ 0 | ||
Pension Plans [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant | 0 | 0 | ||||||||
Defined Benefit Plan, Plan Assets, Benefits Paid | (13.1) | (44.6) | ||||||||
Defined Benefit Plan, Benefit Obligation, Benefits Paid | (13.1) | (44.6) | ||||||||
Settlement | 11.7 | 0 | 14.2 | |||||||
Accumulated Benefit Obligation | 469 | 458.1 | ||||||||
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] | ||||||||||
Benefit Obligation, Beginning | 500.5 | 500.5 | 514.4 | |||||||
Service cost | 10.1 | 10.3 | 10.3 | |||||||
Interest cost | 19.5 | 19.2 | 19.8 | |||||||
Plan settlements | 35.2 | 0 | ||||||||
Participants' contributions | 0 | 0 | ||||||||
Actuarial gains (losses) | 28.8 | 1.2 | ||||||||
Benefit Obligation, Ending | 510.6 | 510.6 | 500.5 | 514.4 | ||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 457.3 | 457.3 | 464.2 | |||||||
Actual return on plans' assets | 64.2 | 37.7 | ||||||||
Employer contributions | 4 | 0 | ||||||||
Plan settlements | 35.2 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 477.2 | 477.2 | 457.3 | 464.2 | ||||||
Funded Status of Plan | $ (33.4) | $ (43.2) | ||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Service cost | 10.1 | 10.3 | 10.3 | |||||||
Interest cost | 19.5 | 19.2 | 19.8 | |||||||
Expected return on plan assets | (32.8) | (33.1) | (36.5) | |||||||
Defined Benefit Plan, Amortization of Gain (Loss) | (13) | (12.4) | (13.8) | |||||||
Amortization of unrecognized prior service cost | [1] | 0 | 0 | 0.5 | ||||||
Settlement | 11.7 | 0 | 14.2 | |||||||
Net Periodic Benefit Cost | [2] | 21.5 | 8.8 | 22.1 | ||||||
Capitalized Portion of Net Periodic Benefit Cost | $ 3.4 | $ 2.9 | $ 2.6 | |||||||
Assumptions Used Calculating Benefit Obligation, Discount Rate | 3.60% | 4.00% | 4.00% | |||||||
Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets | 7.50% | 7.50% | 7.50% | |||||||
Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase | 4.20% | 4.20% | 4.20% | |||||||
Fair Value of Plan Assets | 477.2 | 457.3 | $ 457.3 | $ 464.2 | $ 464.2 | $ 477.2 | $ 457.3 | $ 464.2 | ||
Pension Plans [Member] | OKLAHOMA | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Additional Pension Expense to Meet State Requirements | (2.3) | 9.9 | (3.1) | |||||||
Pension Plans [Member] | ARKANSAS | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Settlement | (0.9) | (0.1) | (1.9) | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Settlement | (0.9) | (0.1) | (1.9) | |||||||
Pension Plans [Member] | Fair Value, Inputs, Level 3 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | U.S. common stocks [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 0 | 0 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 237.1 | 237.1 | ||||||||
Fair Value of Plan Assets, Ending | 225.9 | 225.9 | 237.1 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 225.9 | 237.1 | 237.1 | 237.1 | 225.9 | 237.1 | ||||
Pension Plans [Member] | U.S. common stocks [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 237.1 | 237.1 | ||||||||
Fair Value of Plan Assets, Ending | 225.9 | 225.9 | 237.1 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 225.9 | 237.1 | 237.1 | 237.1 | 225.9 | 237.1 | ||||
Pension Plans [Member] | U.S. common stocks [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | U.S. treasury notes and bonds [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3],[4] | 0 | 0 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | [4] | 122.3 | 122.3 | |||||||
Fair Value of Plan Assets, Ending | [4] | 169.7 | 169.7 | 122.3 | ||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | [4] | 169.7 | 122.3 | 122.3 | 122.3 | 169.7 | 122.3 | |||
Pension Plans [Member] | U.S. treasury notes and bonds [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | [4] | 122.3 | 122.3 | |||||||
Fair Value of Plan Assets, Ending | [4] | 169.7 | 169.7 | 122.3 | ||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | [4] | 169.7 | 122.3 | 122.3 | 122.3 | 169.7 | 122.3 | |||
Pension Plans [Member] | U.S. treasury notes and bonds [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | [4] | 0 | 0 | |||||||
Fair Value of Plan Assets, Ending | [4] | 0 | 0 | 0 | ||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | [4] | 0 | 0 | 0 | 0 | 0 | 0 | |||
Pension Plans [Member] | Mortgage-backed securities [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 0 | 0 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 59.2 | 59.2 | ||||||||
Fair Value of Plan Assets, Ending | 43.4 | 43.4 | 59.2 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 43.4 | 59.2 | 59.2 | 59.2 | 43.4 | 59.2 | ||||
Pension Plans [Member] | Mortgage-backed securities [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | Mortgage-backed securities [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 59.2 | 59.2 | ||||||||
Fair Value of Plan Assets, Ending | 43.4 | 43.4 | 59.2 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 43.4 | 59.2 | 59.2 | 59.2 | 43.4 | 59.2 | ||||
Pension Plans [Member] | Corporate fixed income and other securities [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 0 | 0 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 137.6 | 137.6 | ||||||||
Fair Value of Plan Assets, Ending | 153.8 | 153.8 | 137.6 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 153.8 | 137.6 | 137.6 | 137.6 | 153.8 | 137.6 | ||||
Pension Plans [Member] | Corporate fixed income and other securities [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | Corporate fixed income and other securities [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 137.6 | 137.6 | ||||||||
Fair Value of Plan Assets, Ending | 153.8 | 153.8 | 137.6 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 153.8 | 137.6 | 137.6 | 137.6 | 153.8 | 137.6 | ||||
Pension Plans [Member] | Commingled fund [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3],[5] | 29.9 | 23.8 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | [5] | 23.8 | 23.8 | |||||||
Fair Value of Plan Assets, Ending | [5] | 23.8 | ||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | [5] | 23.8 | 23.8 | 23.8 | 23.8 | |||||
Pension Plans [Member] | Commingled fund [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | [5] | 0 | 0 | |||||||
Fair Value of Plan Assets, Ending | [5] | 0 | 0 | 0 | ||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | [5] | 0 | 0 | 0 | 0 | 0 | 0 | |||
Pension Plans [Member] | Commingled fund [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | [5] | 0 | 0 | |||||||
Fair Value of Plan Assets, Ending | [5] | 0 | 0 | 0 | ||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | [5] | 0 | 0 | 0 | 0 | 0 | 0 | |||
Pension Plans [Member] | Foreign government bonds [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 0 | 0 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 5.2 | 5.2 | ||||||||
Fair Value of Plan Assets, Ending | 4 | 4 | 5.2 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 4 | 5.2 | 5.2 | 5.2 | 4 | 5.2 | ||||
Pension Plans [Member] | Foreign government bonds [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | Foreign government bonds [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 5.2 | 5.2 | ||||||||
Fair Value of Plan Assets, Ending | 4 | 4 | 5.2 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 4 | 5.2 | 5.2 | 5.2 | 4 | 5.2 | ||||
Pension Plans [Member] | U.S. municipal bonds [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 0 | 0 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 1.9 | 1.9 | ||||||||
Fair Value of Plan Assets, Ending | 1.2 | 1.2 | 1.9 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 1.2 | 1.9 | 1.9 | 1.9 | 1.2 | 1.9 | ||||
Pension Plans [Member] | U.S. municipal bonds [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | U.S. municipal bonds [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 1.9 | 1.9 | ||||||||
Fair Value of Plan Assets, Ending | 1.2 | 1.2 | 1.9 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 1.2 | 1.9 | 1.9 | 1.9 | 1.2 | 1.9 | ||||
Pension Plans [Member] | Money market funds [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 4.3 | 2.2 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 2.2 | 2.2 | ||||||||
Fair Value of Plan Assets, Ending | 4.3 | 4.3 | 2.2 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 4.3 | 2.2 | 2.2 | 2.2 | 4.3 | 2.2 | ||||
Pension Plans [Member] | Money market funds [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | Money market funds [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | Mutual fund [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 0 | 0 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 9 | 9 | ||||||||
Fair Value of Plan Assets, Ending | 7.8 | 7.8 | 9 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 7.8 | 9 | 9 | 9 | 7.8 | 9 | ||||
Pension Plans [Member] | Mutual fund [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 9 | 9 | ||||||||
Fair Value of Plan Assets, Ending | 7.8 | 7.8 | 9 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 7.8 | 9 | 9 | 9 | 7.8 | 9 | ||||
Pension Plans [Member] | Mutual fund [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | Treasury futures, receivable [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 0 | 0 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 10.7 | 10.7 | ||||||||
Fair Value of Plan Assets, Ending | 13.4 | 13.4 | 10.7 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 13.4 | 10.7 | 10.7 | 10.7 | 13.4 | 10.7 | ||||
Pension Plans [Member] | Treasury futures, receivable [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | Treasury futures, receivable [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 10.7 | 10.7 | ||||||||
Fair Value of Plan Assets, Ending | 13.4 | 13.4 | 10.7 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 13.4 | 10.7 | 10.7 | 10.7 | 13.4 | 10.7 | ||||
Pension Plans [Member] | Treasury futures, payable [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 0 | 0 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | (2.3) | (2.3) | ||||||||
Fair Value of Plan Assets, Ending | (11.4) | (11.4) | (2.3) | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | (11.4) | (2.3) | (2.3) | (2.3) | (11.4) | (2.3) | ||||
Pension Plans [Member] | Treasury futures, payable [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | Treasury futures, payable [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | (2.3) | (2.3) | ||||||||
Fair Value of Plan Assets, Ending | (11.4) | (11.4) | (2.3) | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | (11.4) | (2.3) | (2.3) | (2.3) | (11.4) | (2.3) | ||||
Pension Plans [Member] | Cash collateral [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 0 | 0 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0.3 | 0.3 | ||||||||
Fair Value of Plan Assets, Ending | 0.3 | 0.3 | 0.3 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | ||||
Pension Plans [Member] | Cash collateral [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0.3 | 0.3 | ||||||||
Fair Value of Plan Assets, Ending | 0.3 | 0.3 | 0.3 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | ||||
Pension Plans [Member] | Cash collateral [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | Receivable (foreign currency) [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 0 | 0 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0.2 | 0.2 | ||||||||
Fair Value of Plan Assets, Ending | 0.1 | 0.1 | 0.2 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0.1 | 0.2 | 0.2 | 0.2 | 0.1 | 0.2 | ||||
Pension Plans [Member] | Receivable (foreign currency) [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | Receivable (foreign currency) [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0.2 | 0.2 | ||||||||
Fair Value of Plan Assets, Ending | 0.1 | 0.1 | 0.2 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0.1 | 0.2 | 0.2 | 0.2 | 0.1 | 0.2 | ||||
Pension Plans [Member] | Total Plan investments [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Alternative Investment, Fair Value Disclosure | [3] | 34.2 | 26 | |||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 607.2 | 607.2 | ||||||||
Fair Value of Plan Assets, Ending | 642.4 | 642.4 | 607.2 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 642.4 | 607.2 | 607.2 | 607.2 | 642.4 | 607.2 | ||||
Pension Plans [Member] | Total Plan investments [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 368.7 | 368.7 | ||||||||
Fair Value of Plan Assets, Ending | 403.7 | 403.7 | 368.7 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 403.7 | 368.7 | 368.7 | 368.7 | 403.7 | 368.7 | ||||
Pension Plans [Member] | Total Plan investments [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 212.5 | 212.5 | ||||||||
Fair Value of Plan Assets, Ending | 204.5 | 204.5 | 212.5 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 204.5 | 212.5 | 212.5 | 212.5 | 204.5 | 212.5 | ||||
Pension Plans [Member] | Receivable from broker for securities sold [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Pension Plans [Member] | Interest and dividends receivable [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 3 | 3 | ||||||||
Fair Value of Plan Assets, Ending | 3.2 | 3.2 | 3 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 3.2 | 3 | 3 | 3 | 3.2 | 3 | ||||
Pension Plans [Member] | Payable to broker for securities purchased [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | (14.3) | (14.3) | ||||||||
Fair Value of Plan Assets, Ending | (10.3) | (10.3) | (14.3) | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | (10.3) | (14.3) | (14.3) | (14.3) | (10.3) | (14.3) | ||||
Pension Plans [Member] | Plan investments attributable to affiliates [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | (138.6) | (138.6) | ||||||||
Fair Value of Plan Assets, Ending | (158.1) | (158.1) | (138.6) | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | (158.1) | (138.6) | (138.6) | (138.6) | (158.1) | (138.6) | ||||
Pension Plans [Member] | Total Plan assets [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 457.3 | 457.3 | ||||||||
Fair Value of Plan Assets, Ending | 477.2 | 477.2 | 457.3 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 477.2 | 457.3 | 457.3 | 457.3 | 477.2 | 457.3 | ||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant | 2.7 | 2.9 | ||||||||
Defined Benefit Plan, Plan Assets, Benefits Paid | (13.4) | (13.4) | ||||||||
Defined Benefit Plan, Benefit Obligation, Benefits Paid | (13.4) | (13.4) | ||||||||
Settlement | 0.4 | 0 | 0 | |||||||
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] | ||||||||||
Benefit Obligation, Beginning | 166.4 | 166.4 | 176.1 | |||||||
Service cost | 0.4 | 0.6 | 1 | |||||||
Interest cost | 5.6 | 7.4 | 7.9 | |||||||
Plan settlements | 21.1 | 0 | ||||||||
Participants' contributions | 2.7 | 2.9 | ||||||||
Actuarial gains (losses) | 4.6 | (7.2) | ||||||||
Benefit Obligation, Ending | 115.8 | 115.8 | 166.4 | 176.1 | ||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 47.8 | 47.8 | 50 | |||||||
Actual return on plans' assets | 2.5 | 1.8 | ||||||||
Employer contributions | 26.7 | 6.5 | ||||||||
Plan settlements | 21.1 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 45.2 | 45.2 | 47.8 | 50 | ||||||
Funded Status of Plan | $ (70.6) | $ (118.6) | ||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Service cost | 0.4 | 0.6 | 1 | |||||||
Interest cost | 5.6 | 7.4 | 7.9 | |||||||
Expected return on plan assets | (2) | (2.1) | (2.2) | |||||||
Defined Benefit Plan, Amortization of Gain (Loss) | (1.9) | (2.5) | (11.9) | |||||||
Amortization of unrecognized prior service cost | [1] | (2.5) | (6.1) | (13.6) | ||||||
Settlement | 0.4 | 0 | 0 | |||||||
Net Periodic Benefit Cost | [2] | 3.8 | 2.3 | 5 | ||||||
Capitalized Portion of Net Periodic Benefit Cost | $ 1.1 | $ 0.8 | $ 1.6 | |||||||
Assumptions Used Calculating Benefit Obligation, Discount Rate | 3.70% | 4.20% | 4.25% | |||||||
Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets | 4.00% | 4.00% | 4.00% | |||||||
Health Care Cost Trend Rate Assumed for Next Fiscal Year | 6.50% | 7.50% | 6.75% | 6.10% | ||||||
Ultimate Health Care Cost Trend Rate | 4.50% | 4.50% | 4.50% | |||||||
Year that Rate Reaches Ultimate Trend Rate | 2,030 | 2,026 | 2,026 | |||||||
Fair Value of Plan Assets | 45.2 | 47.8 | $ 47.8 | $ 50 | $ 50 | $ 45.2 | $ 47.8 | $ 50 | ||
Other Postretirement Benefit Plans, Defined Benefit [Member] | OKLAHOMA | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Additional Postretirement Medical Expense to Meet State Requirements | 6.2 | 7.9 | $ 5.8 | |||||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Ending | 0.5 | 0.5 | ||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0.5 | 0.5 | 0.5 | |||||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Money market funds [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0.3 | 0.3 | ||||||||
Fair Value of Plan Assets, Ending | 0.3 | |||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0.3 | 0.3 | 0.3 | 0.3 | ||||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 8.4 | 8.4 | ||||||||
Fair Value of Plan Assets, Ending | 10 | 10 | 8.4 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 10 | 8.4 | 8.4 | 8.4 | 10 | 8.4 | ||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Cash [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Ending | 0.5 | 0.5 | ||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0.5 | 0.5 | 0.5 | |||||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | Money market funds [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0.3 | 0.3 | ||||||||
Fair Value of Plan Assets, Ending | 0.3 | |||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0.3 | 0.3 | 0.3 | 0.3 | ||||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | 0 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 44.7 | 44.7 | ||||||||
Fair Value of Plan Assets, Ending | 40.2 | 40.2 | 44.7 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 40.2 | 44.7 | 44.7 | 44.7 | 40.2 | 44.7 | ||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Cash [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Ending | 0 | 0 | ||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | |||||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Money market funds [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 0 | 0 | ||||||||
Fair Value of Plan Assets, Ending | 0 | |||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 0 | 0 | 0 | 0 | ||||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Total Plan investments [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 53.1 | 53.1 | ||||||||
Fair Value of Plan Assets, Ending | 50.2 | 50.2 | 53.1 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | 50.2 | 53.1 | 53.1 | 53.1 | $ 50.2 | 53.1 | ||||
Pension Plans [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment | 0 | 0 | ||||||||
Restoration of Retirement Income Plan [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment | $ 0 | 0 | ||||||||
Less Than 90% [Member] | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Projected Benefit Obligation Funded Status Thresholds Fixed Income | 50.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds Equity | 50.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds | 100.00% | |||||||||
95% [Member] | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Projected Benefit Obligation Funded Status Thresholds Fixed Income | 58.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds Equity | 42.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds | 100.00% | |||||||||
100% [Member] | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Projected Benefit Obligation Funded Status Thresholds Fixed Income | 65.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds Equity | 35.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds | 100.00% | |||||||||
105% [Member] | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Projected Benefit Obligation Funded Status Thresholds Fixed Income | 73.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds Equity | 27.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds | 100.00% | |||||||||
110% [Member] | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Projected Benefit Obligation Funded Status Thresholds Fixed Income | 80.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds Equity | 20.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds | 100.00% | |||||||||
115% [Member] | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Projected Benefit Obligation Funded Status Thresholds Fixed Income | 85.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds Equity | 15.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds | 100.00% | |||||||||
120% [Member] | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Projected Benefit Obligation Funded Status Thresholds Fixed Income | 90.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds Equity | 10.00% | |||||||||
Projected Benefit Obligation Funded Status Thresholds | 100.00% | |||||||||
Domestic All-Cap/Large Cap Equity [Member] | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Target Plan Asset Allocations | 40.00% | |||||||||
Domestic Mid-Cap Equity [Member] | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Target Plan Asset Allocations | 15.00% | |||||||||
Domestic Small-Cap Equity [Member] | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Target Plan Asset Allocations | 25.00% | |||||||||
International Equity [Member] | ||||||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Target Plan Asset Allocations | 20.00% | |||||||||
OG&E [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Employer contributions | $ 4 | 0 | ||||||||
OG&E [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member] | ||||||||||
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] | ||||||||||
Fair Value of Plan Assets, Beginning | 47.8 | 47.8 | ||||||||
Fair Value of Plan Assets, Ending | 45.2 | 45.2 | 47.8 | |||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] | ||||||||||
Fair Value of Plan Assets | $ 45.2 | $ 47.8 | $ 47.8 | $ 47.8 | $ 45.2 | $ 47.8 | ||||
Minimum [Member] | Domestic All-Cap/Large Cap Equity [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Target Allocation Percentage | 0.35 | |||||||||
Minimum [Member] | Domestic Mid-Cap Equity [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Target Allocation Percentage | 0.05 | |||||||||
Minimum [Member] | Domestic Small-Cap Equity [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Target Allocation Percentage | 0.05 | |||||||||
Minimum [Member] | International Equity [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Target Allocation Percentage | 0.1 | |||||||||
Maximum [Member] | Domestic All-Cap/Large Cap Equity [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Target Allocation Percentage | 0.6 | |||||||||
Maximum [Member] | Domestic Mid-Cap Equity [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Target Allocation Percentage | 0.25 | |||||||||
Maximum [Member] | Domestic Small-Cap Equity [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Target Allocation Percentage | 0.3 | |||||||||
Maximum [Member] | International Equity [Member] | ||||||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||||||
Defined Benefit Plan, Target Allocation Percentage | 0.3 | |||||||||
[1] | Unamortized prior service cost is amortized on a straight-line basis over the average remaining service period to the first eligibility age of participants who are expected to receive a benefit and are active at the date of the plan amendment. | |||||||||
[2] | In addition to the $26.0 million, $11.8 million and $27.4 million of net periodic benefit cost recognized in 2017, 2016 and 2015, respectively, OG&E recognized the following: •a change in pension expense in 2017, 2016 and 2015 of $(2.3) million, $9.9 million and $(3.1) million, respectively, to maintain the allowable amount to be recovered for pension expense in the Oklahoma jurisdiction, which are included in the Pension tracker regulatory asset or liability (see Note 1);•an increase in postretirement medical expense in 2017, 2016 and 2015 of $6.2 million, $7.9 million and $5.8 million, respectively, to maintain the allowable amount to be recovered for postretirement medical expense in the Oklahoma jurisdiction which are included in the Pension tracker regulatory asset or liability (see Note 1); and •a deferral of pension expense in 2017, 2016 and 2015 of $0.9 million, $0.1 million and $1.9 million related to the Arkansas jurisdictional portion of the pension settlement charge of $11.7 million, $0.4 million and $14.2 million, respectively. | |||||||||
[3] | GAAP allows the measurement of certain investments that do not have a readily determinable fair value at the net asset value. These investments do not consider the observability of inputs; therefore, they are not included within the fair value hierarchy. | |||||||||
[4] | This category represents U.S. Treasury notes and bonds with a Moody's Investors Services rating of Aaa and Government Agency Bonds with a Moody's Investors Services rating of A1 or higher. | |||||||||
[5] | This category represents units of participation in a commingled fund that primarily invested in stocks of international companies and emerging markets. |
Retirement Plans and Postreti52
Retirement Plans and Postretirement Benefit Plans Postretirement Benefit Plans (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended | |||
Dec. 31, 2017 | Sep. 30, 2017 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | ||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment | $ 42.9 | |||||
Defined Benefit Plan, Plan Assets, Payment for Settlement | 26.4 | |||||
Plan settlements | (27.9) | |||||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||||||
Level 3 Asset Value, Beginning of Period | 44.7 | $ 44.7 | ||||
Interest income | 0.8 | |||||
Dividend income | 0.5 | |||||
Unrealized gains | 0.3 | |||||
Realized losses | (0.1) | |||||
Administrative expenses and charges | (0.1) | |||||
Claims paid | (5.9) | |||||
Level 3 Asset Value, End of Period | $ 40.2 | 40.2 | $ 44.7 | |||
Postretirement Plan, Expected Future Benefit Payments in Year One | 9.3 | 9.3 | ||||
Postretirement Plan, Expected Future Benefit Payments in Year Two | 9.3 | 9.3 | ||||
Postretirement Plan, Expected Future Benefit Payments in Year Three | 9.4 | 9.4 | ||||
Postretirement Plan, Expected Future Benefit Payments in Year Four | 9.3 | 9.3 | ||||
Postretirement Plan, Expected Future Benefit Payments in Year Five | 9.3 | 9.3 | ||||
Postretirement Plan, Expected Future Benefit Payments Thereafter | 37.5 | 37.5 | ||||
Postemployment Benefits Liability | 2.2 | $ 2.2 | $ 2.1 | |||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement | 11.7 | $ 14.2 | ||||
Net Effect of Settlement on Other Comprehensive Income and Regulatory Assets | $ 2.1 | |||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate | 2,030 | 2,026 | 2,026 | |||
Plan settlements | $ 21.1 | $ 0 | ||||
Benefit Obligation | 115.8 | 115.8 | 166.4 | $ 176.1 | ||
Fair Value of Plan Assets | 45.2 | 45.2 | 47.8 | 50 | ||
Funded Status of Plan | (70.6) | (70.6) | (118.6) | |||
Plan investments attributable to affiliates | (5) | (5) | (5.3) | |||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement | (0.4) | 0 | 0 | |||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 10 | 10 | 8.4 | |||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0 | 0 | 0 | |||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 40.2 | 40.2 | 44.7 | |||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Group Retiree Medical Insurance Contract [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 40.2 | 40.2 | 44.7 | |||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Group Retiree Medical Insurance Contract [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0 | 0 | 0 | |||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Group Retiree Medical Insurance Contract [Member] | Fair Value, Inputs, Level 3 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 40.2 | 40.2 | 44.7 | |||
Other Postretirement Benefit Plans, Defined Benefit [Member] | U.S. Equity Mutual Funds Investment [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 9.5 | 9.5 | 8.1 | |||
Other Postretirement Benefit Plans, Defined Benefit [Member] | U.S. Equity Mutual Funds Investment [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 9.5 | 9.5 | 8.1 | |||
Other Postretirement Benefit Plans, Defined Benefit [Member] | U.S. Equity Mutual Funds Investment [Member] | Fair Value, Inputs, Level 3 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0 | 0 | 0 | |||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Money market funds [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0.3 | |||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Money market funds [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0.3 | |||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Money market funds [Member] | Fair Value, Inputs, Level 3 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0 | |||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0.5 | 0.5 | ||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0.5 | 0.5 | ||||
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash [Member] | Fair Value, Inputs, Level 3 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0 | 0 | ||||
Pension Plans [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Plan settlements | 35.2 | 0 | ||||
Benefit Obligation | 510.6 | 510.6 | 500.5 | 514.4 | ||
Fair Value of Plan Assets | 477.2 | 477.2 | 457.3 | 464.2 | ||
Funded Status of Plan | (33.4) | (33.4) | (43.2) | |||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement | (11.7) | 0 | (14.2) | |||
Pension Plans [Member] | Fair Value, Inputs, Level 3 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0 | 0 | 0 | |||
Cash Collateral [Member] | Pension Plans [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0.3 | 0.3 | 0.3 | |||
Alternative Investment, Fair Value Disclosure | [1] | 0 | 0 | 0 | ||
Cash Collateral [Member] | Pension Plans [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0.3 | 0.3 | 0.3 | |||
Cash Collateral [Member] | Pension Plans [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 0 | 0 | 0 | |||
Total Plan investments [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 50.2 | 50.2 | 53.1 | |||
Total Plan investments [Member] | Pension Plans [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 642.4 | 642.4 | 607.2 | |||
Alternative Investment, Fair Value Disclosure | [1] | 34.2 | 34.2 | 26 | ||
Total Plan investments [Member] | Pension Plans [Member] | Fair Value, Inputs, Level 1 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 403.7 | 403.7 | 368.7 | |||
Total Plan investments [Member] | Pension Plans [Member] | Fair Value, Inputs, Level 2 [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | 204.5 | 204.5 | 212.5 | |||
OG&E [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member] | ||||||
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||||
Fair Value of Plan Assets | $ 45.2 | 45.2 | 47.8 | |||
ARKANSAS | Pension Plans [Member] | ||||||
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||||||
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement | $ 0.9 | $ 0.1 | $ 1.9 | |||
[1] | GAAP allows the measurement of certain investments that do not have a readily determinable fair value at the net asset value. These investments do not consider the observability of inputs; therefore, they are not included within the fair value hierarchy. |
Commitments and Contingencies C
Commitments and Contingencies Commitments and Contingencies (Details) $ in Millions | 12 Months Ended | ||
Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) | Dec. 31, 2015USD ($) | |
Loss Contingencies [Line Items] | |||
Operating Leases, Future Minimum Payments Due, Next Twelve Months | $ 4.2 | ||
Operating Leases, Future Minimum Payments, Due in Two Years | 23.4 | ||
Operating Leases, Future Minimum Payments, Due in Three Years | 2.9 | ||
Operating Leases, Future Minimum Payments, Due in Four Years | 2.9 | ||
Operating Leases, Future Minimum Payments, Due in Five Years | 2.9 | ||
Operating Leases, Future Minimum Payments, Due Thereafter | 40.6 | ||
Operating Leases, Future Minimum Payments Due | 76.9 | ||
Operating Leases, Rent Expense, Net | 5.4 | $ 8.5 | $ 6.9 |
Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 402.8 | ||
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 244.4 | ||
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 173.2 | ||
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 170.9 | ||
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 168.5 | ||
Unrecorded Unconditional Purchase Obligation | 1,159.8 | ||
Utilities Operating Expense, Purchased Power under Long-term Contracts | 61.1 | 61 | 56.6 |
OG&E cogeneration capacity and fixed operation and maintenance payments [Member] | |||
Loss Contingencies [Line Items] | |||
Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 72.8 | ||
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 65.3 | ||
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 53.2 | ||
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 49.5 | ||
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 45.4 | ||
Unrecorded Unconditional Purchase Obligation | 286.2 | ||
OG&E expected cogeneration energy payments [Member] | |||
Loss Contingencies [Line Items] | |||
Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 35.7 | ||
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 35.6 | ||
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 35.9 | ||
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 37.1 | ||
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 38.3 | ||
Unrecorded Unconditional Purchase Obligation | 182.6 | ||
OG&E minimum fuel purchase commitments [Member] | |||
Loss Contingencies [Line Items] | |||
Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 139.8 | ||
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 36.2 | ||
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 24.6 | ||
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 24.6 | ||
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 24.6 | ||
Unrecorded Unconditional Purchase Obligation | 249.8 | ||
OG&E expected wind purchase commitments [Member] | |||
Loss Contingencies [Line Items] | |||
Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 58.7 | ||
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 56.5 | ||
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 56.9 | ||
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 57.3 | ||
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 57.8 | ||
Unrecorded Unconditional Purchase Obligation | 287.2 | ||
OG&E long-term service agreement commitments [Member] | |||
Loss Contingencies [Line Items] | |||
Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 7.9 | ||
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 41.9 | ||
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 2.4 | ||
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 2.4 | ||
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 2.4 | ||
Unrecorded Unconditional Purchase Obligation | 57 | ||
Mustang Modernization [Member] | |||
Loss Contingencies [Line Items] | |||
Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 24.9 | ||
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 0 | ||
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 0 | ||
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 0 | ||
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 0 | ||
Unrecorded Unconditional Purchase Obligation | 24.9 | ||
Environmental Compliance Plan expenditures [Member] | |||
Loss Contingencies [Line Items] | |||
Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | 63 | ||
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 8.9 | ||
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 0.2 | ||
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 0 | ||
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 0 | ||
Unrecorded Unconditional Purchase Obligation | $ 72.1 | ||
Public Utility Regulatory Policy Act of 1978 [Member] | |||
Loss Contingencies [Line Items] | |||
Percentage of output purchased | 100.00% | ||
OG&E total cogeneration payments [Member] | |||
Loss Contingencies [Line Items] | |||
Long-term Purchase Commitment, Amount | $ 115.2 | 124.8 | 124 |
OG&E capacity payments [Member] | |||
Loss Contingencies [Line Items] | |||
Long-term Purchase Commitment, Amount | 63 | 66.3 | 69.5 |
CPV Keenan [Member] | |||
Loss Contingencies [Line Items] | |||
Utilities Operating Expense, Purchased Power under Long-term Contracts | 29 | 29.2 | 26.7 |
Edison Mission Energy [Member] | |||
Loss Contingencies [Line Items] | |||
Utilities Operating Expense, Purchased Power under Long-term Contracts | 22.1 | 21.1 | 19.7 |
FPL Energy [Member] | |||
Loss Contingencies [Line Items] | |||
Utilities Operating Expense, Purchased Power under Long-term Contracts | 2.6 | 3.4 | 3.2 |
NextEra Energy [Member] | |||
Loss Contingencies [Line Items] | |||
Utilities Operating Expense, Purchased Power under Long-term Contracts | $ 7.4 | $ 7.3 | $ 7 |
OG&E long-term service agreement commitments [Member] | McClain Plant [Member] | |||
Loss Contingencies [Line Items] | |||
Factored-Fired Hours | 128,000 | ||
Factored-Fired Starts | 4,800 | ||
OG&E long-term service agreement commitments [Member] | Redbud Plant [Member] | |||
Loss Contingencies [Line Items] | |||
Additional Factored-Fired Hours | 24,000 | ||
Factored-Fired Hours | 144,000 | ||
Factored-Fired Starts | 4,500 | ||
OG&E Railcar Lease Agreement [Member] | |||
Loss Contingencies [Line Items] | |||
Operating Leases, Future Minimum Payments Due, Next Twelve Months | $ 1.7 | ||
Operating Leases, Future Minimum Payments, Due in Two Years | 20.9 | ||
Operating Leases, Future Minimum Payments, Due in Three Years | 0 | ||
Operating Leases, Future Minimum Payments, Due in Four Years | 0 | ||
Operating Leases, Future Minimum Payments, Due in Five Years | 0 | ||
Operating Leases, Future Minimum Payments, Due Thereafter | 0 | ||
Operating Leases, Future Minimum Payments Due | 22.6 | ||
OG&E Wind Farm Land Lease Agreements [Member] | |||
Loss Contingencies [Line Items] | |||
Operating Leases, Future Minimum Payments Due, Next Twelve Months | 2.5 | ||
Operating Leases, Future Minimum Payments, Due in Two Years | 2.5 | ||
Operating Leases, Future Minimum Payments, Due in Three Years | 2.9 | ||
Operating Leases, Future Minimum Payments, Due in Four Years | 2.9 | ||
Operating Leases, Future Minimum Payments, Due in Five Years | 2.9 | ||
Operating Leases, Future Minimum Payments, Due Thereafter | 40.6 | ||
Operating Leases, Future Minimum Payments Due | 54.3 | ||
Maximum [Member] | |||
Loss Contingencies [Line Items] | |||
Loss Contingency, Range of Possible Loss, Maximum | $ 18.2 |
Rate Matters and Regulation (De
Rate Matters and Regulation (Details) - USD ($) $ in Millions | 12 Months Ended | |||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2014 | ||
Public Utilities, Approved Equity Capital Structure, Percentage | 53.00% | |||
Public Utilities, Approved Debt Capital Structure, Percentage | 47.00% | |||
Interim Rate Refund Amount | $ 47.5 | |||
Regulatory Assets, Current | 40.8 | $ 121.8 | ||
Recommended Disallowance for Fuel Adjustment | $ 3.3 | |||
Oklahoma Corporation Commission [Member] | ||||
OG&E's Jurisdictional Revenues | 85.00% | |||
Arkansas Public Service Commission [Member] | ||||
OG&E's Jurisdictional Revenues | 8.00% | |||
Federal Energy Regulatory Commission [Member] | ||||
OG&E's Jurisdictional Revenues | 7.00% | |||
Administrative Law Judge [Member] | ||||
Recommended Return on Equity | 9.87% | |||
Recommended Increase (Decrease) in Revenue | $ 40.7 | |||
Recommended Capital Structure, Equity Percentage | 53.00% | |||
Recommended Capital Structure, Debt Percentage | 47.00% | |||
Dry Scrubber Project [Member] | ||||
Estimated Environmental Capital Costs | $ 542.4 | |||
Public Utilities, Property, Plant and Equipment, Construction Work in Progress | 401.3 | |||
Mustang Modernization [Member] | ||||
Estimated Environmental Capital Costs | 390 | |||
Public Utilities, Property, Plant and Equipment, Construction Work in Progress | 348.4 | |||
OKLAHOMA | ||||
Public Utilities, Requested Rate Increase (Decrease), Amount | $ 92.5 | |||
Public Utilities, Requested Return on Equity, Percentage | 10.25% | |||
Public Utilities, Requested Equity Capital Structure, Percentage | 53.00% | |||
Investments Since Last Rate Case | $ 1,600 | |||
Public Utilities, Interim Rate Increase (Decrease), Amount | 69.5 | |||
Interim Rate Revenue Reserved | 5.6 | |||
Public Utilities, Approved Rate Increase (Decrease), Amount | $ 8.8 | |||
Public Utilities, Approved Return on Equity, Percentage | 9.50% | |||
Approved Depreciation Reduction from ALJ Recommendation | $ 28.6 | |||
ALJ Depreciation Recommendation | $ 36.4 | |||
Approved Recovery of Short-term Incentive Comp | 50.00% | |||
ARKANSAS | ||||
Public Utilities, Requested Rate Increase (Decrease), Amount | $ 16.5 | |||
Public Utilities, Requested Return on Equity, Percentage | 10.25% | |||
Investments Since Last Rate Case | $ 3,000 | |||
Settlement of Rate Increase | $ 7.1 | |||
Settlement of Return on Equity, Percentage | 9.50% | |||
Settlement of Equity Capital Structure, Percentage | 50.00% | |||
Public Utilities, Inventory, Fuel [Member] | ||||
Deferred Costs and Other Assets | $ 11 | |||
Oklahoma demand program rider under recovery [Member] | ||||
Regulatory Assets, Current | [1] | $ 31.6 | $ 51 | |
January 16, 2018 [Member] | OKLAHOMA | ||||
Public Utilities, Requested Rate Increase (Decrease), Amount | $ 1.9 | |||
Public Utilities, Requested Return on Equity, Percentage | 9.90% | |||
FERC [Member] | ||||
Recommended Common Equity Percentage | 7.85% | |||
Public Utilities, Approved Return on Equity, Percentage | 10.60% | |||
Revenue impact of recommended change in return on common equity | $ 1.5 | |||
[1] | Included in Other Current Assets on the Balance Sheets. |
Quarterly Financial Data (Detai
Quarterly Financial Data (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended | |||||||||
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Operating revenues | $ 501.9 | $ 716.8 | $ 586.4 | $ 456 | $ 530.8 | $ 743.9 | $ 551.4 | $ 433.1 | $ 2,261.1 | $ 2,259.2 | $ 2,196.9 |
Operating income | 92.2 | 243.6 | 145.7 | 45.6 | 81.8 | 257.3 | 131.8 | 38.8 | 527.1 | 509.7 | 516.4 |
Net income | $ 41.6 | $ 161.5 | $ 86.2 | $ 16.2 | $ 45.8 | $ 159.9 | $ 72.3 | $ 6.1 | $ 305.5 | $ 284.1 | $ 268.9 |