XML 97 R56.htm IDEA: XBRL DOCUMENT
v3.24.3

Fair Value Assets and Liabilities (Details) - USD ($) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023 | Dec. 31, 2023
Risk Management Assets |  | $ 495,000,000.0 |  |  | $ 495,000,000.0 |  |  | $ 538,700,000 |
Risk Management Liabilities |  | 353,600,000 |  |  | 353,600,000 |  |  | 471,400,000 |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 282,000,000.0 |  |  | 282,000,000.0 |  |  | 263,200,000 |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 4,425,800,000 |  |  | 4,425,800,000 |  |  | 3,860,200,000 |
Total Assets |  | (5,202,800,000) |  |  | (5,202,800,000) |  |  | (4,662,100,000) |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 495,000,000.0 |  |  | 495,000,000.0 |  |  | 538,700,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 353,600,000 |  |  | 353,600,000 |  |  | 471,400,000 |
Changes in the Fair Value of Net Trading Derivatives and other investments |  |  |  |  |  |  |  |  |
Beginning Balance |  | 288,200,000 |  | $ 126,100,000 | 139,400,000 |  | $ 160,400,000 |  |
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings | [1],[2] | 60,400,000 |  | 39,700,000 | 90,600,000 |  | (41,300,000) |  |
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date | [2] | (6,900,000) |  | 72,700,000 | 2,300,000 |  | 67,700,000 |  |
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income | [3] | (100,000) |  | 4,900,000 | 1,500,000 |  | (10,500,000) |  |
Settlements |  | (133,100,000) |  | (87,100,000) | (164,700,000) |  | (85,900,000) |  |
Transfers into Level 3 | [4],[5] | (300,000) |  |  | 6,800,000 |  | (6,100,000) |  |
Transfers out of Level 3 | [5] | (600,000) |  | 6,600,000 | 2,200,000 |  | 3,800,000 |  |
Changes in Fair Value Allocated to Regulated Jurisdiction | [6] | (14,500,000) |  | 19,900,000 | 115,000,000.0 |  | 94,700,000 |  |
Ending Balance |  | 193,100,000 |  | 182,800,000 | 193,100,000 |  | 182,800,000 |  |
Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 3,900,000 |  |  | 3,900,000 |  |  | 9,700,000 |
Risk Management Liabilities |  | 7,500,000 |  |  | 7,500,000 |  |  | 24,700,000 |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 265,000,000.0 |  |  | 265,000,000.0 |  |  | 249,300,000 |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 2,827,400,000 |  |  | 2,827,400,000 |  |  | 2,444,400,000 |
Total Assets |  | (3,096,300,000) |  |  | (3,096,300,000) |  |  | (2,703,400,000) |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 3,900,000 |  |  | 3,900,000 |  |  | 9,700,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 7,500,000 |  |  | 7,500,000 |  |  | 24,700,000 |
Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 655,400,000 |  |  | 655,400,000 |  |  | 860,400,000 |
Risk Management Liabilities |  | 675,900,000 |  |  | 675,900,000 |  |  | 900,800,000 |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 0 |  |  | 0 |  |  | 0 |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,587,800,000 |  |  | 1,587,800,000 |  |  | 1,406,800,000 |
Total Assets |  | (2,243,200,000) |  |  | (2,243,200,000) |  |  | (2,267,200,000) |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 655,400,000 |  |  | 655,400,000 |  |  | 860,400,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 675,900,000 |  |  | 675,900,000 |  |  | 900,800,000 |
Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 327,300,000 |  |  | 327,300,000 |  |  | 294,100,000 |
Risk Management Liabilities |  | 134,200,000 |  |  | 134,200,000 |  |  | 154,700,000 |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 0 |  |  | 0 |  |  | 0 |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Total Assets |  | (327,300,000) |  |  | (327,300,000) |  |  | (294,100,000) |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 327,300,000 |  |  | 327,300,000 |  |  | 294,100,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 134,200,000 |  |  | 134,200,000 |  |  | 154,700,000 |
Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | (491,600,000) |  |  | (491,600,000) |  |  | (625,500,000) |
Risk Management Liabilities |  | (464,000,000.0) |  |  | (464,000,000.0) |  |  | (608,800,000) |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 17,000,000.0 |  |  | 17,000,000.0 |  |  | 13,900,000 |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 10,600,000 |  |  | 10,600,000 |  |  | 9,000,000.0 |
Total Assets |  | (464,000,000.0) |  |  | (464,000,000.0) |  |  | (602,600,000) |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | (491,600,000) |  |  | (491,600,000) |  |  | (625,500,000) |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | (464,000,000.0) |  |  | (464,000,000.0) |  |  | (608,800,000) |
2024 [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Fair Value Measurements 1 (Textuals) |  |  |  |  |  |  |  |  |
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities |  | (1,000,000) |  |  | (1,000,000) |  |  | (11,000,000) |
2024 [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Fair Value Measurements 1 (Textuals) |  |  |  |  |  |  |  |  |
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities |  | (23,000,000) |  |  | (23,000,000) |  |  | (99,000,000) |
2024 [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Measurements 1 (Textuals) |  |  |  |  |  |  |  |  |
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities |  | 45,000,000 |  |  | 45,000,000 |  |  | 74,000,000 |
2025 - 2027 [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Fair Value Measurements 1 (Textuals) |  |  |  |  |  |  |  |  |
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities |  | (2,000,000) |  |  | (2,000,000) |  |  | (4,000,000) |
2025 - 2027 [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Fair Value Measurements 1 (Textuals) |  |  |  |  |  |  |  |  |
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities |  | 15,000,000 |  |  | 15,000,000 |  |  | (44,000,000) |
2025 - 2027 [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Measurements 1 (Textuals) |  |  |  |  |  |  |  |  |
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities |  | 129,000,000 |  |  | 129,000,000 |  |  | 43,000,000 |
2028 - 2029 [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Fair Value Measurements 1 (Textuals) |  |  |  |  |  |  |  |  |
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities |  | 5,000,000 |  |  | 5,000,000 |  |  | 7,000,000 |
2028 - 2029 [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Measurements 1 (Textuals) |  |  |  |  |  |  |  |  |
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities |  | 17,000,000 |  |  | 17,000,000 |  |  | 18,000,000 |
Maturity Period Four [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Fair Value Measurements 1 (Textuals) |  |  |  |  |  |  |  |  |
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities |  |  |  |  |  |  |  | 2,000,000 |
Maturity Period Four [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Measurements 1 (Textuals) |  |  |  |  |  |  |  |  |
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities |  | (18,000,000) |  |  | (18,000,000) |  |  | (16,000,000) |
Risk Management Commodity Contracts [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 398,500,000 | [7] |  | 398,500,000 | [7] |  | 403,900,000 | [9]
Risk Management Liabilities | [8] | 259,400,000 | [7] |  | 259,400,000 | [7] |  | 362,300,000 | [9]
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 398,500,000 | [7] |  | 398,500,000 | [7] |  | 403,900,000 | [9]
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 259,400,000 | [7] |  | 259,400,000 | [7] |  | 362,300,000 | [9]
Risk Management Commodity Contracts [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 3,900,000 | [7] |  | 3,900,000 | [7] |  | 9,700,000 | [9]
Risk Management Liabilities | [8] | 7,500,000 | [7] |  | 7,500,000 | [7] |  | 24,700,000 | [9]
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 3,900,000 | [7] |  | 3,900,000 | [7] |  | 9,700,000 | [9]
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 7,500,000 | [7] |  | 7,500,000 | [7] |  | 24,700,000 | [9]
Risk Management Commodity Contracts [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 571,500,000 | [7] |  | 571,500,000 | [7] |  | 736,900,000 | [9]
Risk Management Liabilities | [8] | 574,800,000 | [7] |  | 574,800,000 | [7] |  | 783,800,000 | [9]
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 571,500,000 | [7] |  | 571,500,000 | [7] |  | 736,900,000 | [9]
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 574,800,000 | [7] |  | 574,800,000 | [7] |  | 783,800,000 | [9]
Risk Management Commodity Contracts [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 307,200,000 | [7] |  | 307,200,000 | [7] |  | 274,300,000 | [9]
Risk Management Liabilities | [8] | 133,600,000 | [7] |  | 133,600,000 | [7] |  | 154,100,000 | [9]
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 307,200,000 | [7] |  | 307,200,000 | [7] |  | 274,300,000 | [9]
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 133,600,000 | [7] |  | 133,600,000 | [7] |  | 154,100,000 | [9]
Risk Management Commodity Contracts [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (484,100,000) | [7] |  | (484,100,000) | [7] |  | (617,000,000.0) | [9]
Risk Management Liabilities | [8] | (456,500,000) | [7] |  | (456,500,000) | [7] |  | (600,300,000) | [9]
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (484,100,000) | [7] |  | (484,100,000) | [7] |  | (617,000,000.0) | [9]
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | (456,500,000) | [7] |  | (456,500,000) | [7] |  | (600,300,000) | [9]
Energy Contracts [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 199,900,000 |  |  | 199,900,000 |  |  | 225,500,000 |
Risk Management Liabilities |  | 130,400,000 |  |  | 130,400,000 |  |  | 144,900,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 199,900,000 |  |  | 199,900,000 |  |  | 225,500,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 130,400,000 |  |  | 130,400,000 |  |  | 144,900,000 |
Energy Contracts [Member] | Weighted Average [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | 45.50 |  |  | 45.50 |  |  | 45.05 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | 45.50 |  |  | 45.50 |  |  | 45.05 |
Energy Contracts [Member] | Low [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 0.46 |  |  | 0.46 |  |  | 5.21 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 0.46 |  |  | 0.46 |  |  | 5.21 |
Energy Contracts [Member] | High [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 121.80 |  |  | 121.80 |  |  | 153.77 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 121.80 |  |  | 121.80 |  |  | 153.77 |
Natural Gas Contracts [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  |  |  |  |  |  |  | 0 |
Risk Management Liabilities |  |  |  |  |  |  |  | 500,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  |  |  |  |  |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 500,000 |
Natural Gas Contracts [Member] | Weighted Average [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [11],[12] |  |  |  |  |  |  | 3.11 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [11],[12] |  |  |  |  |  |  | 3.11 |
Natural Gas Contracts [Member] | Low [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [12] |  |  |  |  |  |  | 3.11 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [12] |  |  |  |  |  |  | 3.11 |
Natural Gas Contracts [Member] | High [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [12] |  |  |  |  |  |  | 3.11 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [12] |  |  |  |  |  |  | 3.11 |
FTRs [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 127,400,000 |  |  | 127,400,000 |  |  | 68,600,000 |
Risk Management Liabilities |  | 3,800,000 |  |  | 3,800,000 |  |  | 9,300,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 127,400,000 |  |  | 127,400,000 |  |  | 68,600,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 3,800,000 |  |  | 3,800,000 |  |  | 9,300,000 |
FTRs [Member] | Weighted Average [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | 0.20 |  |  | 0.20 |  |  | 0 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | 0.20 |  |  | 0.20 |  |  | 0 |
FTRs [Member] | Low [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | (41.91) |  |  | (41.91) |  |  | (25.45) |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | (41.91) |  |  | (41.91) |  |  | (25.45) |
FTRs [Member] | High [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 24.96 |  |  | 24.96 |  |  | 17.07 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 24.96 |  |  | 24.96 |  |  | 17.07 |
Commodity Hedges [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 96,500,000 |  |  | 96,500,000 |  |  | 134,800,000 |
Risk Management Liabilities | [8] | 1,600,000 |  |  | 1,600,000 |  |  | 1,700,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 96,500,000 |  |  | 96,500,000 |  |  | 134,800,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 1,600,000 |  |  | 1,600,000 |  |  | 1,700,000 |
Commodity Hedges [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 0 |  |  | 0 |  |  | 0 |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Commodity Hedges [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 83,900,000 |  |  | 83,900,000 |  |  | 123,500,000 |
Risk Management Liabilities | [8] | 8,500,000 |  |  | 8,500,000 |  |  | 9,600,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 83,900,000 |  |  | 83,900,000 |  |  | 123,500,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 8,500,000 |  |  | 8,500,000 |  |  | 9,600,000 |
Commodity Hedges [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 20,100,000 |  |  | 20,100,000 |  |  | 19,800,000 |
Risk Management Liabilities | [8] | 600,000 |  |  | 600,000 |  |  | 600,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 20,100,000 |  |  | 20,100,000 |  |  | 19,800,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 600,000 |  |  | 600,000 |  |  | 600,000 |
Commodity Hedges [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (7,500,000) |  |  | (7,500,000) |  |  | (8,500,000) |
Risk Management Liabilities | [8] | (7,500,000) |  |  | (7,500,000) |  |  | (8,500,000) |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (7,500,000) |  |  | (7,500,000) |  |  | (8,500,000) |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | (7,500,000) |  |  | (7,500,000) |  |  | (8,500,000) |
Interest Rate [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  |  |
Risk Management Liabilities |  | 10,900,000 |  |  | 10,900,000 |  |  | 9,000,000.0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 10,900,000 |  |  | 10,900,000 |  |  | 9,000,000.0 |
Interest Rate [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  |  |
Risk Management Liabilities |  | 10,900,000 |  |  | 10,900,000 |  |  | 9,000,000.0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 10,900,000 |  |  | 10,900,000 |  |  | 9,000,000.0 |
Interest Rate [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Interest Rate [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Fair Value Hedges [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 81,700,000 |  |  | 81,700,000 |  |  | 98,400,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 81,700,000 |  |  | 81,700,000 |  |  | 98,400,000 |
Fair Value Hedges [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Fair Value Hedges [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 81,700,000 |  |  | 81,700,000 |  |  | 98,400,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 81,700,000 |  |  | 81,700,000 |  |  | 98,400,000 |
Fair Value Hedges [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Fair Value Hedges [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  | 0 |
AEP Texas Inc. [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 2,700,000 |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 45,100,000 |  |  | 45,100,000 |  |  | 34,000,000.0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 2,700,000 |
AEP Texas Inc. [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 0 |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 45,100,000 |  |  | 45,100,000 |  |  | 34,000,000.0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 0 |
AEP Texas Inc. [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 2,900,000 |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 2,900,000 |
AEP Texas Inc. [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 0 |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 0 |
AEP Texas Inc. [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | (200,000) |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | (200,000) |
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | (600,000) |  |  | (600,000) |  |  | 200,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | (600,000) |  |  | (600,000) |  |  | 200,000 |
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
AEP Texas Inc. [Member] | Risk Management Commodity Contracts [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 600,000 |  |  | 600,000 |  |  | (200,000) |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 600,000 |  |  | 600,000 |  |  | (200,000) |
AEP Texas Inc. [Member] | Interest Rate [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 2,700,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 2,700,000 |
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 0 |
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 2,700,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 2,700,000 |
AEP Texas Inc. [Member] | Interest Rate [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 0 |
AEP Texas Inc. [Member] | Interest Rate [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 0 |
Appalachian Power Co [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 8,300,000 |  |  | 8,300,000 |  |  | 14,900,000 |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Total Assets |  | (55,400,000) |  |  | (55,400,000) |  |  | (37,300,000) |
Changes in the Fair Value of Net Trading Derivatives and other investments |  |  |  |  |  |  |  |  |
Beginning Balance |  | 67,800,000 |  | 39,400,000 | 22,400,000 |  | 69,100,000 |  |
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings | [1],[2] | 13,400,000 |  | 10,000,000.0 | 24,100,000 |  | (47,000,000.0) |  |
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date | [2] | 0 |  | 0 | 0 |  | 0 |  |
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income | [3] | 0 |  | 0 | 0 |  | 0 |  |
Settlements |  | (26,900,000) |  | (16,500,000) | (46,500,000) |  | (22,100,000) |  |
Transfers into Level 3 | [4],[5] | 0 |  |  | 0 |  | 0 |  |
Transfers out of Level 3 | [5] | 0 |  | 100,000 | 0 |  | 0 |  |
Changes in Fair Value Allocated to Regulated Jurisdiction | [6] | (7,100,000) |  | 12,100,000 | 47,200,000 |  | 45,100,000 |  |
Ending Balance |  | 47,200,000 |  | 45,100,000 | 47,200,000 |  | 45,100,000 |  |
Appalachian Power Co [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 8,300,000 |  |  | 8,300,000 |  |  | 14,900,000 |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Total Assets |  | (8,300,000) |  |  | (8,300,000) |  |  | (14,900,000) |
Appalachian Power Co [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 0 |  |  | 0 |  |  | 0 |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Total Assets |  | (7,300,000) |  |  | (7,300,000) |  |  | (1,100,000) |
Appalachian Power Co [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 0 |  |  | 0 |  |  | 0 |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Total Assets |  | (47,500,000) |  |  | (47,500,000) |  |  | (23,500,000) |
Appalachian Power Co [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 0 |  |  | 0 |  |  | 0 |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Total Assets |  | (7,700,000) |  |  | (7,700,000) |  |  | (2,200,000) |
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 47,100,000 |  |  | 47,100,000 |  |  | 22,400,000 |
Risk Management Liabilities | [8] | 13,500,000 |  |  | 13,500,000 |  |  | 22,500,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 47,100,000 |  |  | 47,100,000 |  |  | 22,400,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 13,500,000 |  |  | 13,500,000 |  |  | 22,500,000 |
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 0 |  |  | 0 |  |  | 0 |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 7,300,000 |  |  | 7,300,000 |  |  | 1,100,000 |
Risk Management Liabilities | [8] | 21,900,000 |  |  | 21,900,000 |  |  | 24,000,000.0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 7,300,000 |  |  | 7,300,000 |  |  | 1,100,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 21,900,000 |  |  | 21,900,000 |  |  | 24,000,000.0 |
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 47,500,000 |  |  | 47,500,000 |  |  | 23,500,000 |
Risk Management Liabilities | [8] | 300,000 |  |  | 300,000 |  |  | 1,100,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 47,500,000 |  |  | 47,500,000 |  |  | 23,500,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 300,000 |  |  | 300,000 |  |  | 1,100,000 |
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (7,700,000) |  |  | (7,700,000) |  |  | (2,200,000) |
Risk Management Liabilities | [8] | (8,700,000) |  |  | (8,700,000) |  |  | (2,600,000) |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (7,700,000) |  |  | (7,700,000) |  |  | (2,200,000) |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | (8,700,000) |  |  | (8,700,000) |  |  | (2,600,000) |
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 47,500,000 |  |  | 47,500,000 |  |  | 23,500,000 |
Risk Management Liabilities |  | 300,000 |  |  | 300,000 |  |  | 1,100,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 47,500,000 |  |  | 47,500,000 |  |  | 23,500,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 300,000 |  |  | 300,000 |  |  | 1,100,000 |
Appalachian Power Co [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | 1.30 |  |  | 1.30 |  |  | 1.36 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | 1.30 |  |  | 1.30 |  |  | 1.36 |
Appalachian Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | (0.06) |  |  | (0.06) |  |  | (1.04) |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | (0.06) |  |  | (0.06) |  |  | (1.04) |
Appalachian Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 9.63 |  |  | 9.63 |  |  | 6.45 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 9.63 |  |  | 9.63 |  |  | 6.45 |
Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 4,425,800,000 |  |  | 4,425,800,000 |  |  | 3,860,200,000 |
Total Assets |  | (4,447,500,000) |  |  | (4,447,500,000) |  |  | (3,899,800,000) |
Changes in the Fair Value of Net Trading Derivatives and other investments |  |  |  |  |  |  |  |  |
Beginning Balance |  | 14,500,000 |  | 6,800,000 | 2,800,000 |  | 4,600,000 |  |
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings | [1],[2] | 2,900,000 |  | 2,300,000 | 7,300,000 |  | (1,700,000) |  |
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date | [2] | 0 |  | 0 | 0 |  | 0 |  |
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income | [3] | 0 |  | 0 | 0 |  | 0 |  |
Settlements |  | (7,900,000) |  | (3,700,000) | (10,000,000.0) |  | (2,900,000) |  |
Transfers into Level 3 | [4],[5] | 0 |  |  | 0 |  | 0 |  |
Transfers out of Level 3 | [5] | 0 |  | (100,000) | 0 |  | 0 |  |
Changes in Fair Value Allocated to Regulated Jurisdiction | [6] | (200,000) |  | 1,300,000 | 9,200,000 |  | 6,600,000 |  |
Ending Balance |  | 9,300,000 |  | 6,600,000 | 9,300,000 |  | 6,600,000 |  |
Indiana Michigan Power Co [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 2,827,400,000 |  |  | 2,827,400,000 |  |  | 2,444,400,000 |
Total Assets |  | (2,827,400,000) |  |  | (2,827,400,000) |  |  | (2,444,400,000) |
Indiana Michigan Power Co [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,587,800,000 |  |  | 1,587,800,000 |  |  | 1,406,800,000 |
Total Assets |  | (1,600,500,000) |  |  | (1,600,500,000) |  |  | (1,444,200,000) |
Indiana Michigan Power Co [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Total Assets |  | (10,000,000.0) |  |  | (10,000,000.0) |  |  | (4,500,000) |
Indiana Michigan Power Co [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 10,600,000 |  |  | 10,600,000 |  |  | 9,000,000.0 |
Total Assets |  | (9,600,000) |  |  | (9,600,000) |  |  | (6,700,000) |
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 21,700,000 |  |  | 21,700,000 |  |  | 39,600,000 |
Risk Management Liabilities | [8] | 400,000 |  |  | 400,000 |  |  | 2,000,000.0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 21,700,000 |  |  | 21,700,000 |  |  | 39,600,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 400,000 |  |  | 400,000 |  |  | 2,000,000.0 |
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 0 |  |  | 0 |  |  | 0 |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 12,700,000 |  |  | 12,700,000 |  |  | 37,400,000 |
Risk Management Liabilities | [8] | 900,000 |  |  | 900,000 |  |  | 3,700,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 12,700,000 |  |  | 12,700,000 |  |  | 37,400,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 900,000 |  |  | 900,000 |  |  | 3,700,000 |
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 10,000,000.0 |  |  | 10,000,000.0 |  |  | 4,500,000 |
Risk Management Liabilities | [8] | 700,000 |  |  | 700,000 |  |  | 1,700,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 10,000,000.0 |  |  | 10,000,000.0 |  |  | 4,500,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 700,000 |  |  | 700,000 |  |  | 1,700,000 |
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (1,000,000.0) |  |  | (1,000,000.0) |  |  | (2,300,000) |
Risk Management Liabilities | [8] | (1,200,000) |  |  | (1,200,000) |  |  | (3,400,000) |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (1,000,000.0) |  |  | (1,000,000.0) |  |  | (2,300,000) |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | (1,200,000) |  |  | (1,200,000) |  |  | (3,400,000) |
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 10,000,000.0 |  |  | 10,000,000.0 |  |  | 4,500,000 |
Risk Management Liabilities |  | 700,000 |  |  | 700,000 |  |  | 1,700,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 10,000,000.0 |  |  | 10,000,000.0 |  |  | 4,500,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 700,000 |  |  | 700,000 |  |  | 1,700,000 |
Indiana Michigan Power Co [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | 1.21 |  |  | 1.21 |  |  | 0.85 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | 1.21 |  |  | 1.21 |  |  | 0.85 |
Indiana Michigan Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | (5.00) |  |  | (5.00) |  |  | (1.48) |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | (5.00) |  |  | (5.00) |  |  | (1.48) |
Indiana Michigan Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 9.63 |  |  | 9.63 |  |  | 8.40 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 9.63 |  |  | 9.63 |  |  | 8.40 |
Ohio Power Co [Member] |  |  |  |  |  |  |  |  |
Changes in the Fair Value of Net Trading Derivatives and other investments |  |  |  |  |  |  |  |  |
Beginning Balance |  | (43,200,000) |  | (54,000,000.0) | (50,600,000) |  | (40,000,000.0) |  |
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings | [1],[2] | (100,000) |  | 0 | (900,000) |  | (2,400,000) |  |
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date | [2] | 0 |  | 0 | 0 |  | 0 |  |
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income | [3] | 0 |  | 0 | 0 |  | 0 |  |
Settlements |  | 1,000,000.0 |  | 1,100,000 | 6,000,000.0 |  | 3,500,000 |  |
Transfers into Level 3 | [4],[5] | 0 |  |  | 0 |  | 0 |  |
Transfers out of Level 3 | [5] | 0 |  | 0 | 0 |  | 0 |  |
Changes in Fair Value Allocated to Regulated Jurisdiction | [6] | (9,300,000) |  | 1,300,000 | (6,100,000) |  | (12,700,000) |  |
Ending Balance |  | (51,600,000) |  | (51,600,000) | (51,600,000) |  | (51,600,000) |  |
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 51,600,000 | [8] |  | 51,600,000 | [8] |  | 50,700,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 51,600,000 | [8] |  | 51,600,000 | [8] |  | 50,700,000 |
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 | [8] |  | 0 | [8] |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 | [8] |  | 0 | [8] |  | 0 |
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 400,000 | [8] |  | 400,000 | [8] |  | 200,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 400,000 | [8] |  | 400,000 | [8] |  | 200,000 |
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 51,600,000 | [8] |  | 51,600,000 | [8] |  | 50,600,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 51,600,000 | [8] |  | 51,600,000 | [8] |  | 50,600,000 |
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | (400,000) |  |  | (400,000) |  |  | (100,000) |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | (400,000) |  |  | (400,000) |  |  | (100,000) |
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Risk Management Liabilities |  | 51,600,000 |  |  | 51,600,000 |  |  | 50,600,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 51,600,000 |  |  | 51,600,000 |  |  | 50,600,000 |
Ohio Power Co [Member] | Energy Contracts [Member] | Weighted Average [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | 41.34 |  |  | 41.34 |  |  | 42.85 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | 41.34 |  |  | 41.34 |  |  | 42.85 |
Ohio Power Co [Member] | Energy Contracts [Member] | Low [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 19.94 |  |  | 19.94 |  |  | 22.92 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 19.94 |  |  | 19.94 |  |  | 22.92 |
Ohio Power Co [Member] | Energy Contracts [Member] | High [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 68.22 |  |  | 68.22 |  |  | 67.53 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 68.22 |  |  | 68.22 |  |  | 67.53 |
Public Service Co Of Oklahoma [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 22,400,000 |  |  | 22,400,000 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 22,400,000 |  |  | 22,400,000 |  |  |  |
Changes in the Fair Value of Net Trading Derivatives and other investments |  |  |  |  |  |  |  |  |
Beginning Balance |  | 49,400,000 |  | 43,100,000 | 18,600,000 |  | 23,700,000 |  |
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings | [1],[2] | 23,200,000 |  | 14,200,000 | 26,200,000 |  | 3,500,000 |  |
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date | [2] | 0 |  | 0 | 0 |  | 0 |  |
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income | [3] | 0 |  | 0 | 0 |  | 0 |  |
Settlements |  | (46,300,000) |  | (30,500,000) | (44,800,000) |  | (27,200,000) |  |
Transfers into Level 3 | [4],[5] | 0 |  |  | 0 |  | 0 |  |
Transfers out of Level 3 | [5] | 0 |  | 0 | 0 |  | 0 |  |
Changes in Fair Value Allocated to Regulated Jurisdiction | [6] | 2,100,000 |  | 400,000 | 28,400,000 |  | 27,200,000 |  |
Ending Balance |  | 28,400,000 |  | 27,200,000 | 28,400,000 |  | 27,200,000 |  |
Public Service Co Of Oklahoma [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Public Service Co Of Oklahoma [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 23,100,000 |  |  | 23,100,000 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 23,100,000 |  |  | 23,100,000 |  |  |  |
Public Service Co Of Oklahoma [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 200,000 |  |  | 200,000 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 200,000 |  |  | 200,000 |  |  |  |
Public Service Co Of Oklahoma [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | (900,000) |  |  | (900,000) |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | (900,000) |  |  | (900,000) |  |  |  |
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 28,500,000 |  |  | 28,500,000 |  |  | 19,000,000.0 |
Risk Management Liabilities | [8] | 22,400,000 |  |  | 22,400,000 |  |  | 29,900,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 28,500,000 |  |  | 28,500,000 |  |  | 19,000,000.0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 22,400,000 |  |  | 22,400,000 |  |  | 29,900,000 |
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 0 |  |  | 0 |  |  | 0 |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 600,000 |  |  | 600,000 |  |  | 0 |
Risk Management Liabilities | [8] | 12,200,000 |  |  | 12,200,000 |  |  | 29,600,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 600,000 |  |  | 600,000 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 12,200,000 |  |  | 12,200,000 |  |  | 29,600,000 |
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 28,600,000 |  |  | 28,600,000 |  |  | 19,700,000 |
Risk Management Liabilities | [8] | 200,000 |  |  | 200,000 |  |  | 1,100,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 28,600,000 |  |  | 28,600,000 |  |  | 19,700,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 200,000 |  |  | 200,000 |  |  | 1,100,000 |
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (700,000) |  |  | (700,000) |  |  | (700,000) |
Risk Management Liabilities | [8] | 10,000,000.0 |  |  | 10,000,000.0 |  |  | (800,000) |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (700,000) |  |  | (700,000) |  |  | (700,000) |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 10,000,000.0 |  |  | 10,000,000.0 |  |  | (800,000) |
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 28,600,000 |  |  | 28,600,000 |  |  | 19,700,000 |
Risk Management Liabilities |  | 200,000 |  |  | 200,000 |  |  | 1,100,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 28,600,000 |  |  | 28,600,000 |  |  | 19,700,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 200,000 |  |  | 200,000 |  |  | 1,100,000 |
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | (3.82) |  |  | (3.82) |  |  | (4.33) |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | (3.82) |  |  | (3.82) |  |  | (4.33) |
Public Service Co Of Oklahoma [Member] | FTRs [Member] | Low [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | (41.91) |  |  | (41.91) |  |  | (25.45) |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | (41.91) |  |  | (41.91) |  |  | (25.45) |
Public Service Co Of Oklahoma [Member] | FTRs [Member] | High [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 5.93 |  |  | 5.93 |  |  | 4.80 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 5.93 |  |  | 5.93 |  |  | 4.80 |
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | (10,900,000) |  |  | (10,900,000) |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | (10,900,000) |  |  | (10,900,000) |  |  |  |
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | (10,900,000) |  |  | (10,900,000) |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | (10,900,000) |  |  | (10,900,000) |  |  |  |
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 10,900,000 |  |  | 10,900,000 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 10,900,000 |  |  | 10,900,000 |  |  |  |
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 10,900,000 |  |  | 10,900,000 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 10,900,000 |  |  | 10,900,000 |  |  |  |
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Public Service Co Of Oklahoma [Member] | Interest Rate [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 0 |  |  | 0 |  |  |  |
Southwestern Electric Power Co [Member] |  |  |  |  |  |  |  |  |
Changes in the Fair Value of Net Trading Derivatives and other investments |  |  |  |  |  |  |  |  |
Beginning Balance |  | 38,100,000 |  | 26,000,000.0 | 11,100,000 |  | 14,200,000 |  |
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings | [1],[2] | 21,200,000 |  | 14,000,000.0 | 23,600,000 |  | 5,900,000 |  |
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date | [2] | 0 |  | 0 | 0 |  | 0 |  |
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income | [3] | 0 |  | 0 | 0 |  | 0 |  |
Settlements |  | (37,700,000) |  | (24,800,000) | (36,000,000.0) |  | (20,000,000.0) |  |
Transfers into Level 3 | [4],[5] | 0 |  |  | 0 |  | 0 |  |
Transfers out of Level 3 | [5] | 0 |  | 0 | 500,000 |  | 0 |  |
Changes in Fair Value Allocated to Regulated Jurisdiction | [6] | 2,100,000 |  | 1,300,000 | 24,500,000 |  | 16,400,000 |  |
Ending Balance |  | 23,700,000 |  | $ 16,500,000 | 23,700,000 |  | $ 16,500,000 |  |
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 24,100,000 |  |  | 24,100,000 |  |  | 11,600,000 |
Risk Management Liabilities | [8] | 4,800,000 |  |  | 4,800,000 |  |  | 15,600,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 24,100,000 |  |  | 24,100,000 |  |  | 11,600,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 4,800,000 |  |  | 4,800,000 |  |  | 15,600,000 |
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 0 |  |  | 0 |  |  | 0 |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 0 |  |  | 0 |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 0 |  |  | 0 |  |  | 0 |
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 300,000 |  |  | 300,000 |  |  | 500,000 |
Risk Management Liabilities | [8] | 5,000,000.0 |  |  | 5,000,000.0 |  |  | 15,700,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 300,000 |  |  | 300,000 |  |  | 500,000 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 5,000,000.0 |  |  | 5,000,000.0 |  |  | 15,700,000 |
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 24,300,000 |  |  | 24,300,000 |  |  | 12,000,000.0 |
Risk Management Liabilities | [8] | 600,000 |  |  | 600,000 |  |  | 900,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | 24,300,000 |  |  | 24,300,000 |  |  | 12,000,000.0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | 600,000 |  |  | 600,000 |  |  | 900,000 |
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (500,000) |  |  | (500,000) |  |  | (900,000) |
Risk Management Liabilities | [8] | (800,000) |  |  | (800,000) |  |  | (1,000,000.0) |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets | [8] | (500,000) |  |  | (500,000) |  |  | (900,000) |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities | [8] | (800,000) |  |  | (800,000) |  |  | (1,000,000.0) |
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  |  |  |  |  |  |  | 0 |
Risk Management Liabilities |  |  |  |  |  |  |  | 500,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  |  |  |  |  |  |  | 0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  |  |  |  |  |  |  | 500,000 |
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Weighted Average [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [11],[12] |  |  |  |  |  |  | 3.11 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [11],[12] |  |  |  |  |  |  | 3.11 |
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | Low [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [12] |  |  |  |  |  |  | 3.11 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [12] |  |  |  |  |  |  | 3.11 |
Southwestern Electric Power Co [Member] | Natural Gas Contracts [Member] | High [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [12] |  |  |  |  |  |  | 3.11 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [12] |  |  |  |  |  |  | 3.11 |
Southwestern Electric Power Co [Member] | FTRs [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 24,300,000 |  |  | 24,300,000 |  |  | 12,000,000.0 |
Risk Management Liabilities |  | 600,000 |  |  | 600,000 |  |  | 400,000 |
Risk Management Assets |  |  |  |  |  |  |  |  |
Risk Management Assets |  | 24,300,000 |  |  | 24,300,000 |  |  | 12,000,000.0 |
Liabilities, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Risk Management Liabilities |  | 600,000 |  |  | 600,000 |  |  | 400,000 |
Southwestern Electric Power Co [Member] | FTRs [Member] | Weighted Average [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | (3.82) |  |  | (3.82) |  |  | (4.33) |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10],[11] | (3.82) |  |  | (3.82) |  |  | (4.33) |
Southwestern Electric Power Co [Member] | FTRs [Member] | Low [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | (41.91) |  |  | (41.91) |  |  | (25.45) |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | (41.91) |  |  | (41.91) |  |  | (25.45) |
Southwestern Electric Power Co [Member] | FTRs [Member] | High [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 5.93 |  |  | 5.93 |  |  | 4.80 |
Level 3 Quantitative Information |  |  |  |  |  |  |  |  |
Fair Value Significant Unobservable Input Price Per Unit | [10] | 5.93 |  |  | 5.93 |  |  | 4.80 |
Cash [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 53,400,000 |  |  | 53,400,000 |  |  | 48,900,000 |
Other Short-term Investments | [13] | 53,400,000 |  |  | 53,400,000 |  |  | 48,900,000 |
Cash [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 53,400,000 |  |  | 53,400,000 |  |  | 48,900,000 |
Cash [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 0 |  |  | 0 |  |  | 0 |
Cash [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 0 |  |  | 0 |  |  | 0 |
Cash [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Cash and Cash Equivalents |  | 0 |  |  | 0 |  |  | 0 |
Other Cash Deposits [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 17,000,000.0 |  |  | 17,000,000.0 |  |  | 13,900,000 |
Other Cash Deposits [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 0 |  |  | 0 |  |  | 0 |
Other Cash Deposits [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 0 |  |  | 0 |  |  | 0 |
Other Cash Deposits [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 0 |  |  | 0 |  |  | 0 |
Other Cash Deposits [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments | [14] | 17,000,000.0 |  |  | 17,000,000.0 |  |  | 13,900,000 |
Mutual Funds Fixed Income [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments | [15] | 164,600,000 |  |  | 164,600,000 |  |  | 159,700,000 |
Mutual Funds Fixed Income [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 164,600,000 |  |  | 164,600,000 |  |  | 159,700,000 |
Mutual Funds Fixed Income [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 0 |  |  | 0 |  |  | 0 |
Mutual Funds Fixed Income [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 0 |  |  | 0 |  |  | 0 |
Mutual Funds Fixed Income [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments |  | 0 |  |  | 0 |  |  | 0 |
Mutual Funds Equity [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments | [16] | 47,000,000.0 |  |  | 47,000,000.0 |  |  | 40,700,000 |
Mutual Funds Equity [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments | [16] | 47,000,000.0 |  |  | 47,000,000.0 |  |  | 40,700,000 |
Mutual Funds Equity [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments | [16] | 0 |  |  | 0 |  |  | 0 |
Mutual Funds Equity [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments | [16] | 0 |  |  | 0 |  |  | 0 |
Mutual Funds Equity [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Assets, Fair Value Disclosure |  |  |  |  |  |  |  |  |
Other Short-term Investments | [16] | 0 |  |  | 0 |  |  | 0 |
Cash and Cash Equivalents [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [17] | 26,200,000 |  |  | 26,200,000 |  |  | 16,800,000 |
Cash and Cash Equivalents [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [17] | 15,600,000 |  |  | 15,600,000 |  |  | 7,800,000 |
Cash and Cash Equivalents [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [17] | 0 |  |  | 0 |  |  | 0 |
Cash and Cash Equivalents [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [17] | 0 |  |  | 0 |  |  | 0 |
Cash and Cash Equivalents [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [17] | 10,600,000 |  |  | 10,600,000 |  |  | 9,000,000.0 |
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [17] | 26,200,000 |  |  | 26,200,000 |  |  | 16,800,000 |
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [17] | 15,600,000 |  |  | 15,600,000 |  |  | 7,800,000 |
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [17] | 0 |  |  | 0 |  |  | 0 |
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [17] | 0 |  |  | 0 |  |  | 0 |
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [17] | 10,600,000 |  |  | 10,600,000 |  |  | 9,000,000.0 |
US Government Agencies Debt Securities [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,370,500,000 |  |  | 1,370,500,000 |  |  | 1,273,000,000 |
US Government Agencies Debt Securities [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
US Government Agencies Debt Securities [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,370,500,000 |  |  | 1,370,500,000 |  |  | 1,273,000,000 |
US Government Agencies Debt Securities [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
US Government Agencies Debt Securities [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,370,500,000 |  |  | 1,370,500,000 |  |  | 1,273,000,000 |
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,370,500,000 |  |  | 1,370,500,000 |  |  | 1,273,000,000 |
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Corporate Debt [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 215,600,000 |  |  | 215,600,000 |  |  | 132,100,000 |
Corporate Debt [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Corporate Debt [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 215,600,000 |  |  | 215,600,000 |  |  | 132,100,000 |
Corporate Debt [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Corporate Debt [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Corporate Debt [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 215,600,000 |  |  | 215,600,000 |  |  | 132,100,000 |
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 215,600,000 |  |  | 215,600,000 |  |  | 132,100,000 |
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
State and Local Jurisdiction [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,700,000 |  |  | 1,700,000 |  |  | 1,700,000 |
State and Local Jurisdiction [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
State and Local Jurisdiction [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,700,000 |  |  | 1,700,000 |  |  | 1,700,000 |
State and Local Jurisdiction [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
State and Local Jurisdiction [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,700,000 |  |  | 1,700,000 |  |  | 1,700,000 |
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,700,000 |  |  | 1,700,000 |  |  | 1,700,000 |
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Fixed Income Funds [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,587,800,000 |  |  | 1,587,800,000 |  |  | 1,406,800,000 |
Fixed Income Funds [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Fixed Income Funds [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,587,800,000 |  |  | 1,587,800,000 |  |  | 1,406,800,000 |
Fixed Income Funds [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Fixed Income Funds [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,587,800,000 |  |  | 1,587,800,000 |  |  | 1,406,800,000 |
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 1,587,800,000 |  |  | 1,587,800,000 |  |  | 1,406,800,000 |
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  | 0 |  |  | 0 |  |  | 0 |
Domestic [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [16] | 2,811,800,000 |  |  | 2,811,800,000 |  |  | 2,436,600,000 |
Domestic [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [16] | 2,811,800,000 |  |  | 2,811,800,000 |  |  | 2,436,600,000 |
Domestic [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [16] | 0 |  |  | 0 |  |  | 0 |
Domestic [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [16] | 0 |  |  | 0 |  |  | 0 |
Domestic [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [16] | 0 |  |  | 0 |  |  | 0 |
Domestic [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [16] | 2,811,800,000 |  |  | 2,811,800,000 |  |  | 2,436,600,000 |
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [16] | 2,811,800,000 |  |  | 2,811,800,000 |  |  | 2,436,600,000 |
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [16] | 0 |  |  | 0 |  |  | 0 |
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [16] | 0 |  |  | 0 |  |  | 0 |
Domestic [Member] | Indiana Michigan Power Co [Member] | Other [Member] |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts |  |  |  |  |  |  |  |  |
Spent Nuclear Fuel and Decommissioning Trusts | [16] | $ 0 |  |  | $ 0 |  |  | $ 0 |
[1] | Represents the change in fair value between the beginning of the reporting period and the settlement of the risk management commodity contract.
[2] | Included in revenues on the statements of income.
[3] | Included in cash flow hedges on the statements of comprehensive income.
[4] | Represents existing assets or liabilities that were previously categorized as Level 2.
[5] | Transfers are recognized based on their value at the beginning of the reporting period that the transfer occurred.
[6] | Relates to the net gains (losses) of those contracts that are not reflected on the statements of income. These changes in fair value are recorded as regulatory liabilities for net gains and as regulatory assets for net losses or accounts payable.
[7] | 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.
[8] | 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.’’
[9] | 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
[10] | Represents market prices in dollars per MWh.
[11] | The weighted average is the product of the forward market price of the underlying commodity and volume weighted by term.
[12] | Represents market prices in dollars per MMBtu.
[13] | Primarily represents amounts held for the repayment of debt.
[14] | Amounts in “Other’’ column primarily represent cash deposits in bank accounts with financial institutions or third-parties. Level 1 and Level 2 amounts primarily represent investments in money market funds.
[15] | Primarily short and intermediate maturities which may be sold and do not contain maturity dates.
[16] | Amounts represent publicly traded equity securities and equity-based mutual funds.
[17] | Amounts in “Other’’ column primarily represent accrued interest receivables from financial institutions. Level 1 amounts primarily represent investments in money market funds.

X
- Definition This element represents total gains or losses for the period (realized and unrealized), arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), which are allocated to regulated jurisdictions. + References No definition available. + Details
Name: | aep_ChangesInFairValueAllocatedToRegulatedJurisdiction
Namespace Prefix: | aep_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Fair value measurements textuals abstract for assets and liabilities measured on a recurring basis. + References No definition available. + Details
Name: | aep_FairValueMeasurements1TextualsAbstract
Namespace Prefix: | aep_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Price per unit of significant unobservable inputs, such as but not limited to fair value for financial transmission rights agreements and energy contracts. + References No definition available. + Details
Name: | aep_FairValueSignificantUnobservableInputPricePerUnit
Namespace Prefix: | aep_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Maturity of the net fair value of risk management contracts prior to cash collateral, assets or liabilities. + References No definition available. + Details
Name: | aep_MaturityOfNetFairValueOfRiskManagementContractsPriorToCashCollateralAssetsOrLiabilities
Namespace Prefix: | aep_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Nuclear Fuel and Decommissioning Trusts Abstract. + References No definition available. + Details
Name: | aep_NuclearFuelAndDecommissioningTrustsAbstract
Namespace Prefix: | aep_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Funds to pay for the disposal of spent nuclear fuel and the decontaminating and decommissioning of nuclear facilities through the collection of revenues from rate payers. + References No definition available. + Details
Name: | aep_SpentNuclearFuelAndDecommissioningTrusts
Namespace Prefix: | aep_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of asset recognized for present right to economic benefit. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 103 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-103 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-12 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 11: http://www.xbrl.org/2003/role/exampleRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 55 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477439/946-210-55-1 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 20: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(3)(c)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1 Reference 22: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)(Footnote 7)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5C Reference 23: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(3)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1 Reference 24: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5 -Subparagraph (SX 210.12-13(Column A)(Footnote 3)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5 Reference 25: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5C Reference 26: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5A -Subparagraph (SX 210.12-13A(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5A Reference 27: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5B Reference 28: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)(Footnote 4)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5B Reference 29: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483466/210-20-50-3 Reference 30: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 22 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-22 Reference 31: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-10 Reference 32: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 + Details
Name: | us-gaap_DerivativeAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DerivativeAssetsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 16: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(9)(e)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)(Footnote 7)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5C Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(9)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1 Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(9)(d)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1 Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5 -Subparagraph (SX 210.12-13(Column G)(Footnote 8)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5 Reference 22: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5C Reference 23: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5 -Subparagraph (SX 210.12-13(Column G)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5 Reference 24: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5A -Subparagraph (SX 210.12-13A(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5A Reference 25: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5B Reference 26: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)(Footnote 4)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5B Reference 27: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483466/210-20-50-3 Reference 28: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 22 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-22 Reference 29: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-10 Reference 30: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 + Details
Name: | us-gaap_DerivativeLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_FairValueInputsQuantitativeInformationAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of unrealized gain (loss) recognized in income for derivative asset (liability) after deduction of derivative liability (asset), measured at fair value using unobservable input (level 3) and still held. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of gain (loss) recognized in income from derivative asset (liability) after deduction of derivative liability (asset), measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of gain (loss) recognized in other comprehensive income from derivative asset (liability) after deduction of derivative liability (asset), measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInOtherComprehensiveIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationPurchasesSalesIssuesSettlements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of transfers of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset) into level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersIntoLevel3
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of transfers of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset) out of level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationTransfersOutOfLevel3
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_LiabilitiesFairValueDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of short-term investments classified as other. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(5)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)(g)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(8)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)(6)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_OtherShortTermInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_PortionAtOtherThanFairValueFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | aep_MaturityOfFairValueRiskManagementContractsAxis=aep_WithinCurrentYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | aep_MaturityOfFairValueRiskManagementContractsAxis=aep_MaturityPeriod2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | aep_MaturityOfFairValueRiskManagementContractsAxis=aep_MaturityPeriod3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | aep_MaturityOfFairValueRiskManagementContractsAxis=aep_MaturityPeriodFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=aep_RiskManagementCommodityContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=aep_EnergyContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=aep_NaturalGasContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=aep_FinancialTrasnsmissionRightsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CommodityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=aep_InterestRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=aep_AEPTexasInc.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=aep_AppalachianPowerCoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=aep_IndianaMichiganPowerCoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=aep_OhioPowerCoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=aep_PublicServiceCoOfOklahomaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=aep_SouthwesternElectricPowerCoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CashMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=aep_OtherCashDepositsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=aep_MutualFundsFixedIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MutualFundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_StateAndLocalJurisdictionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_FixedIncomeFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=aep_DomesticMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |