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Derivatives and Hedging (Details) gal in Millions, MWh in Millions, MMBTU in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2024 USD ($) MWh MMBTU gal | Sep. 30, 2023 USD ($) | Sep. 30, 2024 USD ($) MWh MMBTU gal | Sep. 30, 2023 USD ($) | Dec. 31, 2023 USD ($) MMBTU MWh gal
Cash Collateral Netting |  |  |  |  |  |  |  |  |
Cash Collateral Received Netted Against Risk Management Assets |  | $ 44,000,000 |  |  | $ 44,000,000 |  |  | $ 46,000,000 |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 236,700,000 |  |  | 236,700,000 |  |  | 217,500,000 |
Long-term Risk Management Assets |  | 258,300,000 |  |  | 258,300,000 |  |  | 321,200,000 |
Total Assets |  | 495,000,000.0 |  |  | 495,000,000.0 |  |  | 538,700,000 |
Current Risk Management Liabilities |  | 152,000,000.0 |  |  | 152,000,000.0 |  |  | 229,600,000 |
Long-term Risk Management Liabilities |  | 201,600,000 |  |  | 201,600,000 |  |  | 241,800,000 |
Total Liabilities |  | 353,600,000 |  |  | 353,600,000 |  |  | 471,400,000 |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (4,400,000) |  | $ 33,100,000 | 69,500,000 |  | $ (179,400,000) |  |
Carrying Amount of Hedged Asset (Liability) | [1],[2] | (890,100,000) |  |  | (890,100,000) |  |  | (878,200,000) |
Cumulative Fair Value Hedging Adjustment in the Carrying Amount of the Hedged Asset (Liability) | [1],[2] | 57,500,000 |  |  | 57,500,000 |  |  | 68,400,000 |
Gain (Loss) on Hedging Instruments |  |  |  |  |  |  |  |  |
Gain (Loss) on Fair Value Hedging Instruments | [3] | 14,800,000 |  | (13,400,000) | 16,700,000 |  | (10,700,000) |  |
Gain (Loss) on Fair Value Portion of Long Term Debt | [3] | (14,800,000) |  | 13,400,000 | (16,700,000) |  | 10,700,000 |  |
Collateral Triggering Events [Abstract] |  |  |  |  |  |  |  |  |
Fair Value Of Derivative Liabilities Subject To Cross Acceleration Provisions |  | 102,000,000 |  |  | 102,000,000 |  |  | 107,000,000 |
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions |  | 174,000,000 |  |  | 174,000,000 |  |  | 242,000,000 |
Derivatives and Hedging (Textuals) [Abstract] |  |  |  |  |  |  |  |  |
Hedged Liability, Discontinued Fair Value Hedge, Cumulative Increase (Decrease) |  | (24,000,000) |  |  | (24,000,000) |  |  | (30,000,000) |
AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Total Liabilities |  |  |  |  |  |  |  | 2,700,000 |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (800,000) |  | 800,000 | (300,000) |  | 200,000 |  |
Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 47,100,000 |  |  | 47,100,000 |  |  | 22,400,000 |
Current Risk Management Liabilities |  | 7,600,000 |  |  | 7,600,000 |  |  | 15,900,000 |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 6,400,000 |  | 13,300,000 | 49,000,000.0 |  | 5,200,000 |  |
Collateral Triggering Events [Abstract] |  |  |  |  |  |  |  |  |
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions |  | 14,000,000 |  |  | 14,000,000 |  |  | 22,000,000 |
Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 21,700,000 |  |  | 21,700,000 |  |  | 27,800,000 |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 1,500,000 |  | (6,300,000) | (7,400,000) |  | 8,200,000 |  |
Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Liabilities |  | 6,300,000 |  |  | 6,300,000 |  |  | 6,800,000 |
Long-term Risk Management Liabilities |  | 45,300,000 |  |  | 45,300,000 |  |  | 43,900,000 |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (9,300,000) |  | 400,000 | (3,700,000) |  | (24,700,000) |  |
Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 28,400,000 |  |  | 28,400,000 |  |  | 19,000,000.0 |
Current Risk Management Liabilities |  | 22,300,000 |  |  | 22,300,000 |  |  | 28,900,000 |
Total Liabilities |  | 22,400,000 |  |  | 22,400,000 |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 35,400,000 |  | 9,300,000 | 95,200,000 |  | 66,200,000 |  |
Collateral Triggering Events [Abstract] |  |  |  |  |  |  |  |  |
Fair Value Of Derivative Liabilities Subject To Cross Acceleration Provisions |  | 11,000,000 |  |  | 11,000,000 |  |  | 0 |
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions |  | 11,000,000 |  |  | 11,000,000 |  |  | 29,000,000 |
Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 24,100,000 |  |  | 24,100,000 |  |  | 11,600,000 |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 28,200,000 |  | 11,500,000 | 83,000,000.0 |  | 54,600,000 |  |
Collateral Triggering Events [Abstract] |  |  |  |  |  |  |  |  |
Fair Value Of Derivative Liabilities Subject To Cross Default Provisions |  | 5,000,000 |  |  | 5,000,000 |  |  | 15,000,000 |
Risk Management Contracts [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Total Assets | [5] | 398,500,000 | [4] |  | 398,500,000 | [4] |  | 403,900,000 | [6]
Total Liabilities | [5] | 259,400,000 | [4] |  | 259,400,000 | [4] |  | 362,300,000 | [6]
Risk Management Contracts [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Total Liabilities | [5] | 0 |  |  | 0 |  |  | 0 |
Risk Management Contracts [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Total Assets | [5] | 47,100,000 |  |  | 47,100,000 |  |  | 22,400,000 |
Total Liabilities | [5] | 13,500,000 |  |  | 13,500,000 |  |  | 22,500,000 |
Risk Management Contracts [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Total Assets | [5] | 21,700,000 |  |  | 21,700,000 |  |  | 39,600,000 |
Total Liabilities | [5] | 400,000 |  |  | 400,000 |  |  | 2,000,000.0 |
Risk Management Contracts [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Total Liabilities |  | 51,600,000 | [5] |  | 51,600,000 | [5] |  | 50,700,000 |
Risk Management Contracts [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Total Assets | [5] | 28,500,000 |  |  | 28,500,000 |  |  | 19,000,000.0 |
Total Liabilities | [5] | 22,400,000 |  |  | 22,400,000 |  |  | 29,900,000 |
Risk Management Contracts [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Total Assets | [5] | 24,100,000 |  |  | 24,100,000 |  |  | 11,600,000 |
Total Liabilities | [5] | 4,800,000 |  |  | 4,800,000 |  |  | 15,600,000 |
Commodity [Member] |  |  |  |  |  |  |  |  |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | 74,900,000 |  |  | 74,900,000 |  |  | 104,900,000 |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | $ 27,300,000 |  |  | 38,300,000 |
Derivatives and Hedging (Textuals) [Abstract] |  |  |  |  |  |  |  |  |
Maximum Term for Exposure to Variability of Future Cash Flows |  |  |  |  | 10 years |  |  |  |
Cross Acceleration Provisions Maximum Third Party Obligation Amount |  | 50,000,000 |  |  | $ 50,000,000 |  |  |  |
Cross Default Provisions Maximum Third Party Obligation Amount |  | 50,000,000 |  |  | 50,000,000 |  |  |  |
Commodity [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | 0 |  |  | 0 |  |  | 0 |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | 0 |  |  | 0 |
Commodity [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | 0 |  |  | 0 |  |  | 0 |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | 0 |  |  | 0 |
Commodity [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | 0 |  |  | 0 |  |  | 0 |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | 0 |  |  | 0 |
Commodity [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | 0 |  |  | 0 |  |  | 0 |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | 0 |  |  | 0 |
Commodity [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | 0 |  |  | 0 |  |  | 0 |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | 0 |  |  | 0 |
Commodity [Member] | Risk Management Contracts [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 444,400,000 |  |  | 444,400,000 |  |  | 555,100,000 |
Long-term Risk Management Assets |  | 448,300,000 |  |  | 448,300,000 |  |  | 468,800,000 |
Current Risk Management Liabilities |  | 334,900,000 |  |  | 334,900,000 |  |  | 588,000,000.0 |
Long-term Risk Management Liabilities |  | 391,100,000 |  |  | 391,100,000 |  |  | 377,600,000 |
Commodity [Member] | Risk Management Contracts [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 500,000 |  |  | 500,000 |  |  | 200,000 |
Long-term Risk Management Liabilities |  | 100,000 |  |  | 100,000 |  |  | 0 |
Commodity [Member] | Risk Management Contracts [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 54,400,000 |  |  | 54,400,000 |  |  | 24,600,000 |
Long-term Risk Management Assets |  | 800,000 |  |  | 800,000 |  |  | 300,000 |
Current Risk Management Liabilities |  | 15,900,000 |  |  | 15,900,000 |  |  | 18,500,000 |
Long-term Risk Management Liabilities |  | 6,700,000 |  |  | 6,700,000 |  |  | 6,900,000 |
Commodity [Member] | Risk Management Contracts [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 22,700,000 |  |  | 22,700,000 |  |  | 30,100,000 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 12,000,000.0 |
Current Risk Management Liabilities |  | 1,500,000 |  |  | 1,500,000 |  |  | 5,400,000 |
Long-term Risk Management Liabilities |  | 100,000 |  |  | 100,000 |  |  | 200,000 |
Commodity [Member] | Risk Management Contracts [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 6,600,000 |  |  | 6,600,000 |  |  | 6,900,000 |
Long-term Risk Management Liabilities |  | 45,400,000 |  |  | 45,400,000 |  |  | 43,900,000 |
Commodity [Member] | Risk Management Contracts [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 28,700,000 |  |  | 28,700,000 |  |  | 19,700,000 |
Long-term Risk Management Assets |  | 600,000 |  |  | 600,000 |  |  | 0 |
Current Risk Management Liabilities |  | 11,900,000 |  |  | 11,900,000 |  |  | 29,700,000 |
Long-term Risk Management Liabilities |  | 600,000 |  |  | 600,000 |  |  | 1,000,000.0 |
Commodity [Member] | Risk Management Contracts [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 24,600,000 |  |  | 24,600,000 |  |  | 12,000,000.0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 500,000 |
Current Risk Management Liabilities |  | 5,600,000 |  |  | 5,600,000 |  |  | 14,900,000 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 1,700,000 |
Commodity [Member] | Hedging Contracts [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 41,200,000 |  |  | 41,200,000 |  |  | 56,700,000 |
Long-term Risk Management Assets |  | 63,300,000 |  |  | 63,300,000 |  |  | 86,800,000 |
Current Risk Management Liabilities |  | 6,700,000 |  |  | 6,700,000 |  |  | 8,200,000 |
Long-term Risk Management Liabilities |  | 2,900,000 |  |  | 2,900,000 |  |  | 2,200,000 |
Commodity [Member] | Hedging Contracts [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Commodity [Member] | Hedging Contracts [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Commodity [Member] | Hedging Contracts [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Commodity [Member] | Hedging Contracts [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Commodity [Member] | Hedging Contracts [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Commodity [Member] | Hedging Contracts [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 1,750,000,000 |  |  | 1,750,000,000 |  |  | 1,300,000,000 |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | (8,200,000) |  |  | (8,200,000) |  |  | (8,100,000) |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | 2,900,000 |  |  | 3,200,000 |
Interest Rate [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 0 |  |  | 0 |  |  | 150,000,000.0 |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | 6,500,000 |  |  | 6,500,000 |  |  | 500,000 |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | 700,000 |  |  | 200,000 |
Interest Rate [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 0 |  |  | 0 |  |  | 0 |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | 5,300,000 |  |  | 5,300,000 |  |  | 5,900,000 |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | 800,000 |  |  | 800,000 |
Interest Rate [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 0 |  |  | 0 |  |  | 0 |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | (5,200,000) |  |  | (5,200,000) |  |  | (5,500,000) |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | (400,000) |  |  | (400,000) |
Interest Rate [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 400,000,000.0 |  |  | 400,000,000.0 |  |  | 0 |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | (8,800,000) |  |  | (8,800,000) |  |  | (200,000) |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | (600,000) |  |  | 0 |
Interest Rate [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 0 |  |  | 0 |  |  | 0 |
Impact of Cash Flow Hedges on the Condensed Balance Sheet |  |  |  |  |  |  |  |  |
AOCI Gain (Loss) Net of Tax |  | 1,100,000 |  |  | 1,100,000 |  |  | 1,300,000 |
Portion Expected to be Reclassified to Net Income During the Next Twelve Months |  |  |  |  | 300,000 |  |  | 300,000 |
Interest Rate [Member] | Hedging Contracts [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 51,700,000 |  |  | 51,700,000 |  |  | 50,500,000 |
Long-term Risk Management Liabilities |  | 40,900,000 |  |  | 40,900,000 |  |  | 56,900,000 |
Interest Rate [Member] | Hedging Contracts [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 2,700,000 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate [Member] | Hedging Contracts [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate [Member] | Hedging Contracts [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate [Member] | Hedging Contracts [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate [Member] | Hedging Contracts [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 10,900,000 |  |  | 10,900,000 |  |  | 0 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate [Member] | Hedging Contracts [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 485,600,000 |  |  | 485,600,000 |  |  | 611,800,000 |
Long-term Risk Management Assets |  | 511,600,000 |  |  | 511,600,000 |  |  | 555,600,000 |
Total Assets |  | 997,200,000 |  |  | 997,200,000 |  |  | 1,167,400,000 |
Current Risk Management Liabilities |  | 393,300,000 |  |  | 393,300,000 |  |  | 646,700,000 |
Long-term Risk Management Liabilities |  | 434,900,000 |  |  | 434,900,000 |  |  | 436,700,000 |
Total Liabilities |  | 828,200,000 |  |  | 828,200,000 |  |  | 1,083,400,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | 169,000,000.0 |  |  | 169,000,000.0 |  |  | 84,000,000.0 |
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Total Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 500,000 |  |  | 500,000 |  |  | 2,900,000 |
Long-term Risk Management Liabilities |  | 100,000 |  |  | 100,000 |  |  | 0 |
Total Liabilities |  | 600,000 |  |  | 600,000 |  |  | 2,900,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | (600,000) |  |  | (600,000) |  |  | (2,900,000) |
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 54,400,000 |  |  | 54,400,000 |  |  | 24,600,000 |
Long-term Risk Management Assets |  | 800,000 |  |  | 800,000 |  |  | 300,000 |
Total Assets |  | 55,200,000 |  |  | 55,200,000 |  |  | 24,900,000 |
Current Risk Management Liabilities |  | 15,900,000 |  |  | 15,900,000 |  |  | 18,500,000 |
Long-term Risk Management Liabilities |  | 6,700,000 |  |  | 6,700,000 |  |  | 6,900,000 |
Total Liabilities |  | 22,600,000 |  |  | 22,600,000 |  |  | 25,400,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | 32,600,000 |  |  | 32,600,000 |  |  | (500,000) |
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 22,700,000 |  |  | 22,700,000 |  |  | 30,100,000 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 12,000,000.0 |
Total Assets |  | 22,700,000 |  |  | 22,700,000 |  |  | 42,100,000 |
Current Risk Management Liabilities |  | 1,500,000 |  |  | 1,500,000 |  |  | 5,400,000 |
Long-term Risk Management Liabilities |  | 100,000 |  |  | 100,000 |  |  | 200,000 |
Total Liabilities |  | 1,600,000 |  |  | 1,600,000 |  |  | 5,600,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | 21,100,000 |  |  | 21,100,000 |  |  | 36,500,000 |
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Total Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 6,600,000 |  |  | 6,600,000 |  |  | 6,900,000 |
Long-term Risk Management Liabilities |  | 45,400,000 |  |  | 45,400,000 |  |  | 43,900,000 |
Total Liabilities |  | 52,000,000.0 |  |  | 52,000,000.0 |  |  | 50,800,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | (52,000,000.0) |  |  | (52,000,000.0) |  |  | (50,800,000) |
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 28,700,000 |  |  | 28,700,000 |  |  | 19,700,000 |
Long-term Risk Management Assets |  | 600,000 |  |  | 600,000 |  |  | 0 |
Total Assets |  | 29,300,000 |  |  | 29,300,000 |  |  | 19,700,000 |
Current Risk Management Liabilities |  | 22,800,000 |  |  | 22,800,000 |  |  | 29,700,000 |
Long-term Risk Management Liabilities |  | 600,000 |  |  | 600,000 |  |  | 1,000,000.0 |
Total Liabilities |  | 23,400,000 |  |  | 23,400,000 |  |  | 30,700,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | 5,900,000 |  |  | 5,900,000 |  |  | (11,000,000.0) |
Gross Amounts of Risk Management Assets/Liabilities Recognized [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 24,600,000 |  |  | 24,600,000 |  |  | 12,000,000.0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 500,000 |
Total Assets |  | 24,600,000 |  |  | 24,600,000 |  |  | 12,500,000 |
Current Risk Management Liabilities |  | 5,600,000 |  |  | 5,600,000 |  |  | 14,900,000 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 1,700,000 |
Total Liabilities |  | 5,600,000 |  |  | 5,600,000 |  |  | 16,600,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | 19,000,000.0 |  |  | 19,000,000.0 |  |  | (4,100,000) |
Gross Amounts Offset in the Statement of Financial Position [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | (248,900,000) |  |  | (248,900,000) |  |  | (394,300,000) |
Long-term Risk Management Assets |  | (253,300,000) |  |  | (253,300,000) |  |  | (234,400,000) |
Current Risk Management Liabilities |  | (241,300,000) |  |  | (241,300,000) |  |  | (417,100,000) |
Long-term Risk Management Liabilities |  | (233,300,000) |  |  | (233,300,000) |  |  | (194,900,000) |
Gross Amounts Offset in the Statement of Financial Position [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | (500,000) |  |  | (500,000) |  |  | (200,000) |
Long-term Risk Management Liabilities |  | (100,000) |  |  | (100,000) |  |  | 0 |
Gross Amounts Offset in the Statement of Financial Position [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | (7,300,000) |  |  | (7,300,000) |  |  | (2,200,000) |
Long-term Risk Management Assets |  | (800,000) |  |  | (800,000) |  |  | (300,000) |
Current Risk Management Liabilities |  | (8,300,000) |  |  | (8,300,000) |  |  | (2,600,000) |
Long-term Risk Management Liabilities |  | (800,000) |  |  | (800,000) |  |  | (300,000) |
Gross Amounts Offset in the Statement of Financial Position [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | (1,000,000.0) |  |  | (1,000,000.0) |  |  | (2,300,000) |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | (200,000) |
Current Risk Management Liabilities |  | (1,200,000) |  |  | (1,200,000) |  |  | (3,400,000) |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | (200,000) |
Gross Amounts Offset in the Statement of Financial Position [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | (300,000) |  |  | (300,000) |  |  | (100,000) |
Long-term Risk Management Liabilities |  | (100,000) |  |  | (100,000) |  |  | 0 |
Gross Amounts Offset in the Statement of Financial Position [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | (300,000) |  |  | (300,000) |  |  | (700,000) |
Long-term Risk Management Assets |  | (500,000) |  |  | (500,000) |  |  | 0 |
Current Risk Management Liabilities |  | (500,000) |  |  | (500,000) |  |  | (800,000) |
Long-term Risk Management Liabilities |  | (500,000) |  |  | (500,000) |  |  | 0 |
Gross Amounts Offset in the Statement of Financial Position [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | (500,000) |  |  | (500,000) |  |  | (400,000) |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | (500,000) |
Current Risk Management Liabilities |  | (800,000) |  |  | (800,000) |  |  | (500,000) |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | (500,000) |
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 236,700,000 |  |  | 236,700,000 |  |  | 217,500,000 |
Long-term Risk Management Assets |  | 258,300,000 |  |  | 258,300,000 |  |  | 321,200,000 |
Total Assets |  | 495,000,000.0 |  |  | 495,000,000.0 |  |  | 538,700,000 |
Current Risk Management Liabilities |  | 152,000,000.0 |  |  | 152,000,000.0 |  |  | 229,600,000 |
Long-term Risk Management Liabilities |  | 201,600,000 |  |  | 201,600,000 |  |  | 241,800,000 |
Total Liabilities |  | 353,600,000 |  |  | 353,600,000 |  |  | 471,400,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | 141,400,000 |  |  | 141,400,000 |  |  | 67,300,000 |
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Total Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 2,700,000 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Total Liabilities |  | 0 |  |  | 0 |  |  | 2,700,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | 0 |  |  | 0 |  |  | (2,700,000) |
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 47,100,000 |  |  | 47,100,000 |  |  | 22,400,000 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Total Assets |  | 47,100,000 |  |  | 47,100,000 |  |  | 22,400,000 |
Current Risk Management Liabilities |  | 7,600,000 |  |  | 7,600,000 |  |  | 15,900,000 |
Long-term Risk Management Liabilities |  | 5,900,000 |  |  | 5,900,000 |  |  | 6,600,000 |
Total Liabilities |  | 13,500,000 |  |  | 13,500,000 |  |  | 22,500,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | 33,600,000 |  |  | 33,600,000 |  |  | (100,000) |
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 21,700,000 |  |  | 21,700,000 |  |  | 27,800,000 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 11,800,000 |
Total Assets |  | 21,700,000 |  |  | 21,700,000 |  |  | 39,600,000 |
Current Risk Management Liabilities |  | 300,000 |  |  | 300,000 |  |  | 2,000,000.0 |
Long-term Risk Management Liabilities |  | 100,000 |  |  | 100,000 |  |  | 0 |
Total Liabilities |  | 400,000 |  |  | 400,000 |  |  | 2,000,000.0 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | 21,300,000 |  |  | 21,300,000 |  |  | 37,600,000 |
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Total Assets |  | 0 |  |  | 0 |  |  | 0 |
Current Risk Management Liabilities |  | 6,300,000 |  |  | 6,300,000 |  |  | 6,800,000 |
Long-term Risk Management Liabilities |  | 45,300,000 |  |  | 45,300,000 |  |  | 43,900,000 |
Total Liabilities |  | 51,600,000 |  |  | 51,600,000 |  |  | 50,700,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | (51,600,000) |  |  | (51,600,000) |  |  | (50,700,000) |
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 28,400,000 |  |  | 28,400,000 |  |  | 19,000,000.0 |
Long-term Risk Management Assets |  | 100,000 |  |  | 100,000 |  |  | 0 |
Total Assets |  | 28,500,000 |  |  | 28,500,000 |  |  | 19,000,000.0 |
Current Risk Management Liabilities |  | 22,300,000 |  |  | 22,300,000 |  |  | 28,900,000 |
Long-term Risk Management Liabilities |  | 100,000 |  |  | 100,000 |  |  | 1,000,000.0 |
Total Liabilities |  | 22,400,000 |  |  | 22,400,000 |  |  | 29,900,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | 6,100,000 |  |  | 6,100,000 |  |  | (10,900,000) |
Net Amounts of Assets/Liabilities Presented in the Statement of Financial Position [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Fair Value of Derivative Instruments |  |  |  |  |  |  |  |  |
Current Risk Management Assets |  | 24,100,000 |  |  | 24,100,000 |  |  | 11,600,000 |
Long-term Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Total Assets |  | 24,100,000 |  |  | 24,100,000 |  |  | 11,600,000 |
Current Risk Management Liabilities |  | 4,800,000 |  |  | 4,800,000 |  |  | 14,400,000 |
Long-term Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 1,200,000 |
Total Liabilities |  | 4,800,000 |  |  | 4,800,000 |  |  | 15,600,000 |
Total MTM Derivative Contract Net Assets (Liabilities) |  | $ 19,300,000 |  |  | $ 19,300,000 |  |  | $ (4,000,000.0) |
Power [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MWh |  | 306.0 |  |  | 306.0 |  |  | 246.8 |
Power [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MWh |  | 0.0 |  |  | 0.0 |  |  | 0.0 |
Power [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MWh |  | 38.6 |  |  | 38.6 |  |  | 16.8 |
Power [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MWh |  | 8.5 |  |  | 8.5 |  |  | 5.9 |
Power [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MWh |  | 2.1 |  |  | 2.1 |  |  | 2.2 |
Power [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MWh |  | 7.0 |  |  | 7.0 |  |  | 4.1 |
Power [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MWh |  | 6.5 |  |  | 6.5 |  |  | 2.9 |
Natural Gas [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MMBTU |  | 161.5 |  |  | 161.5 |  |  | 151.6 |
Natural Gas [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MMBTU |  | 0.0 |  |  | 0.0 |  |  | 0.0 |
Natural Gas [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MMBTU |  | 47.1 |  |  | 47.1 |  |  | 37.3 |
Natural Gas [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MMBTU |  | 0.0 |  |  | 0.0 |  |  | 0.0 |
Natural Gas [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MMBTU |  | 0.0 |  |  | 0.0 |  |  | 0.0 |
Natural Gas [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MMBTU |  | 36.4 |  |  | 36.4 |  |  | 34.9 |
Natural Gas [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Energy Notional Amount | MMBTU |  | 14.7 |  |  | 14.7 |  |  | 17.9 |
Heating Oil and Gasoline [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Volume Notional Amount | gal |  | 7.2 |  |  | 7.2 |  |  | 6.5 |
Heating Oil and Gasoline [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Volume Notional Amount | gal |  | 1.7 |  |  | 1.7 |  |  | 1.8 |
Heating Oil and Gasoline [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Volume Notional Amount | gal |  | 0.9 |  |  | 0.9 |  |  | 1.0 |
Heating Oil and Gasoline [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Volume Notional Amount | gal |  | 1.6 |  |  | 1.6 |  |  | 0.6 |
Heating Oil and Gasoline [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Volume Notional Amount | gal |  | 1.1 |  |  | 1.1 |  |  | 1.2 |
Heating Oil and Gasoline [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Volume Notional Amount | gal |  | 0.7 |  |  | 0.7 |  |  | 0.7 |
Heating Oil and Gasoline [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Volume Notional Amount | gal |  | 0.8 |  |  | 0.8 |  |  | 0.9 |
Interest Rate Contract [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | $ 59,300,000 |  |  | $ 59,300,000 |  |  | $ 80,100,000 |
Interest Rate Contract [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate Contract [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate Contract [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate Contract [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate Contract [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate Contract [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Commodity: |  |  |  |  |  |  |  |  |
Derivative, Notional Amount |  | 0 |  |  | 0 |  |  | $ 0 |
Vertically Integrated Utilities Revenues [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (1,100,000) |  | (9,500,000) | (22,500,000) |  | 2,200,000 |  |
Vertically Integrated Utilities Revenues [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Vertically Integrated Utilities Revenues [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Vertically Integrated Utilities Revenues [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Vertically Integrated Utilities Revenues [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Vertically Integrated Utilities Revenues [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Vertically Integrated Utilities Revenues [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Generation and Marketing Revenues [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (67,100,000) |  | (1,400,000) | (164,800,000) |  | (290,600,000) |  |
Generation and Marketing Revenues [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Generation and Marketing Revenues [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Generation and Marketing Revenues [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Generation and Marketing Revenues [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Generation and Marketing Revenues [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Generation and Marketing Revenues [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Electric Generation, Transmission and Distribution Revenues [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Electric Generation, Transmission and Distribution Revenues [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Electric Generation, Transmission and Distribution Revenues [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 100,000 |  | 100,000 | 200,000 |  | 100,000 |  |
Electric Generation, Transmission and Distribution Revenues [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (1,200,000) |  | (9,600,000) | (22,700,000) |  | 2,100,000 |  |
Electric Generation, Transmission and Distribution Revenues [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Electric Generation, Transmission and Distribution Revenues [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Electric Generation, Transmission and Distribution Revenues [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 700,000 |  | 200,000 | 2,400,000 |  | 2,200,000 |  |
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 500,000 |  | 200,000 | 2,100,000 |  | 2,100,000 |  |
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 100,000 |  | 100,000 |  |
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Purchased Electricity, Fuel and Other Consumables Used for Electric Generation [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | 0 | 0 |  | 0 |  |
Other Operation Expense [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (300,000) |  |  |  |  | (100,000) |  |
Other Operation Expense [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (100,000) |  |  |  |  | 0 |  |
Other Operation Expense [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  |  |  |  | 0 |  |
Other Operation Expense [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (100,000) |  |  |  |  | 0 |  |
Other Operation Expense [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  |  |  |  | 0 |  |
Other Operation Expense [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  |  |  |  | 0 |  |
Other Operation Expense [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  |  |  |  | 0 |  |
Maintenance Expense [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (500,000) |  | (400,000) | 100,000 |  | (600,000) |  |
Maintenance Expense [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (100,000) |  | (100,000) | 0 |  | (200,000) |  |
Maintenance Expense [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (100,000) |  | (100,000) | 0 |  | (100,000) |  |
Maintenance Expense [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (100,000) |  | 0 | 0 |  | 0 |  |
Maintenance Expense [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (100,000) |  | (100,000) | 0 |  | (100,000) |  |
Maintenance Expense [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | 0 |  | (100,000) | 0 |  | (100,000) |  |
Maintenance Expense [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  | (100,000) |  | (100,000) | 0 |  | (100,000) |  |
Regulatory Assets [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | 3,100,000 |  | 1,200,000 | 48,300,000 |  | (36,000,000.0) |  |
Regulatory Assets [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | (600,000) |  | 500,000 | (300,000) |  | 0 |  |
Regulatory Assets [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | (3,900,000) |  | 1,200,000 | 11,200,000 |  | 0 |  |
Regulatory Assets [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | 0 |  | 1,700,000 | 3,000,000.0 |  | (400,000) |  |
Regulatory Assets [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | (9,200,000) |  | 500,000 | (3,700,000) |  | (24,600,000) |  |
Regulatory Assets [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | 11,600,000 |  | (3,500,000) | 19,300,000 |  | (7,000,000.0) |  |
Regulatory Assets [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | 6,500,000 |  | (1,100,000) | 11,600,000 |  | (3,500,000) |  |
Regulatory Liabilities [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | 60,800,000 |  | 43,000,000.0 | 206,000,000.0 |  | 143,500,000 |  |
Regulatory Liabilities [Member] | AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | 0 |  | 400,000 | 0 |  | 400,000 |  |
Regulatory Liabilities [Member] | Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | 9,800,000 |  | 11,900,000 | 35,500,000 |  | 3,100,000 |  |
Regulatory Liabilities [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | 2,900,000 |  | 1,600,000 | 12,200,000 |  | 6,400,000 |  |
Regulatory Liabilities [Member] | Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | 0 |  | 0 | 0 |  | 0 |  |
Regulatory Liabilities [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | 23,800,000 |  | 12,900,000 | 75,900,000 |  | 73,300,000 |  |
Regulatory Liabilities [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts |  |  |  |  |  |  |  |  |
Amount of Gain (Loss) Recognized on Risk Management Contracts | [7] | $ 21,800,000 |  | $ 12,700,000 | $ 71,400,000 |  | $ 58,200,000 |  |
[1] | Amounts include $(24) million and $(30) million as of September 30, 2024 and December 31, 2023, respectively, for the fair value hedge adjustment of hedged debt obligations for which hedge accounting has been discontinued.
[2] | Amounts included within Noncurrent Liabilities line item Long-term Debt on the Balance Sheet.
[3] | Gain (Loss) is included in Interest Expense on the statements of income.
[4] | The September 30, 2024 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 1 matures $(1) million in 2024 and $(2) million in periods 2025-2027; Level 2 matures $(23) million in 2024, $15 million in periods 2025-2027 and $5 million in periods 2028-2029; Level 3 matures $45 million in 2024, $129 million in periods 2025-2027, $17 million in periods 2028-2029 and $(18) million in periods 2030-2032. Risk management commodity contracts are substantially comprised of power contracts.
[5] | Amounts in “Other’’ column primarily represent counterparty netting of risk management and hedging contracts and associated cash collateral under the accounting guidance for “Derivatives and Hedging.’’
[6] | The December 31, 2023 maturities of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), were as follows: Level 1 matures $(11) million in 2024 and $(4) million in 2025-2027; Level 2 matures $(99) million in 2024, $(44) million in periods 2025-2027, $7 million in periods 2028-2029 and $2 million in periods 2030-2033; Level 3 matures $74 million in 2024, $43 million in periods 2025-2027, $18 million in periods 2028-2029 and $(16) million in periods 2030-2033. Risk management commodity contracts are substantially comprised of power contracts
[7] | Represents realized and unrealized gains and losses subject to regulatory accounting treatment recorded as either current or noncurrent on the balance sheets.

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