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VARIABLE INTEREST ENTITIES AND EQUITY METHOD INVESTMENTS - Narrative (Details) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2024 USD ($) line MW | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2025 GW
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | $ 2,637.6 | $ 2,032.5 |  |
Securitized Assets | 554.3 | 336.3 |  |
Construction work in progress | 6,346.9 | 5,508.0 |  |
Investments in Equity Method Investees | 1,055.9 | 1,073.6 | $ 1,276.7 |
Equity Earnings (Loss) of Unconsolidated Subsidiaries | $ 93.7 | 58.5 | (109.4) |
Berkshire Hathaway |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Ownership percentage | 50.00% |  |  |
AEPTHCo |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Ownership percentage | 50.00% |  |  |
ETT |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Investments in Equity Method Investees | $ 897.0 | 811.0 |  |
Equity Earnings (Loss) of Unconsolidated Subsidiaries | 86.0 | 74.0 | 74.0 |
SOUTHWESTERN ELECTRIC POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | 265.5 | 198.9 |  |
Securitized Assets | 331.4 | 0.0 |  |
Construction work in progress | 627.3 | 555.8 |  |
Equity Earnings (Loss) of Unconsolidated Subsidiaries | 1.4 | 1.4 | 1.4 |
SOUTHWESTERN ELECTRIC POWER COMPANY | Affiliated Entity |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | 57.1 | 45.9 |  |
INDIANA MICHIGAN POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | 202.2 | 225.8 |  |
Construction work in progress | 334.9 | 301.7 |  |
INDIANA MICHIGAN POWER COMPANY | Billings from AEP Generating Company |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Billings from VIE | 209.0 | 181.0 | 242.0 |
INDIANA MICHIGAN POWER COMPANY | Carrying Amount in AEP Generating Company's Accounts Payable |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
As Reported on the Balance Sheet | 14.0 | 15.0 |  |
INDIANA MICHIGAN POWER COMPANY | Affiliated Entity |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | 98.5 | 107.3 |  |
AEP TEXAS INC. |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | 366.2 | 192.3 |  |
Securitized Assets | 116.7 | 202.9 |  |
Construction work in progress | 1,118.0 | 904.6 |  |
AEP TEXAS INC. | Affiliated Entity |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | 34.9 | 27.7 |  |
APPALACHIAN POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | 427.2 | 280.4 |  |
Securitized Assets | 106.2 | 133.4 |  |
Construction work in progress | 742.6 | 709.2 |  |
APPALACHIAN POWER COMPANY | Affiliated Entity |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | $ 205.9 | 121.3 |  |
Transource Energy |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Equity and voting ownership percentage | 86.50% |  |  |
AEGCo | Rockport Generating Plant |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Percent of Ownership | 50.00% |  |  |
Cleco Power, LLC |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Percentage of VIE sales of lignite produced | 50.00% |  |  |
OHIO POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | $ 343.6 | 320.7 |  |
Construction work in progress | 691.1 | 654.0 |  |
Equity Earnings (Loss) of Unconsolidated Subsidiaries | (1.1) | 0.0 | 0.6 |
OHIO POWER COMPANY | Affiliated Entity |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | $ 204.9 | 154.2 |  |
Variable Interest Entity, Primary Beneficiary |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Minimum percentage of equity AEP provides | 5.00% |  |  |
Percentage of short term borrowing needs in excess of third party financings | 35.00% |  |  |
Number of lines of insurance for protected cells | line | 7 |  |  |
Insurance premium expense to protected cell | $ 37.0 | 34.0 | 31.0 |
Debt-to-total capitalization maximum | 67.50% |  |  |
Variable Interest Entity, Primary Beneficiary | SOUTHWESTERN ELECTRIC POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Guarantees of mine reclamation amount | $ 155.0 |  |  |
Estimated final cost mine reclamation | 100.0 |  |  |
Amount recorded in ARO for final mine closure and reclamation costs | 96.0 |  |  |
Amount collected through rider for final Mine closure and reclamation costs | 97.0 |  |  |
Amount recorded in other noncurrent assets for final mine closure and reclamation costs | 76.0 |  |  |
Securitized Assets | 331.0 |  |  |
Variable Interest Entity, Primary Beneficiary | SOUTHWESTERN ELECTRIC POWER COMPANY | Affiliated Entity |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Accounts Payable - Affiliated Companies for collected reclamation costs that have been billed to SWEPCo | 77.0 |  |  |
Variable Interest Entity, Primary Beneficiary | INDIANA MICHIGAN POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Capital lease payments made | $ 111.0 | 97.0 | 84.0 |
Capital lease term | 54 months |  |  |
Variable Interest Entity, Primary Beneficiary | AEP TEXAS INC. | AEP Texas Restoration Funding |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Securitized Assets | $ 117.0 | 139.0 |  |
Variable Interest Entity, Primary Beneficiary | AEP TEXAS INC. | AEP Texas Transition Funding |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Securitized Assets |  | 64.0 |  |
Variable Interest Entity, Primary Beneficiary | APPALACHIAN POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Securitized Assets | $ 106.0 | 133.0 |  |
Variable Interest Entity, Primary Beneficiary | Great Plains Energy Inc. |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Equity and voting ownership percentage | 13.50% |  |  |
Variable Interest Entity, Primary Beneficiary | Current Liabilities | SOUTHWESTERN ELECTRIC POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Securitization Bonds | $ 23.0 |  |  |
Variable Interest Entity, Primary Beneficiary | Current Liabilities | AEP TEXAS INC. | AEP Texas Restoration Funding |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Securitization Bonds | 24.0 | 24.0 |  |
Variable Interest Entity, Primary Beneficiary | Current Liabilities | AEP TEXAS INC. | AEP Texas Transition Funding |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Securitization Bonds |  | 72.0 |  |
Variable Interest Entity, Primary Beneficiary | Current Liabilities | APPALACHIAN POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Securitization Bonds | 28.0 | 27.0 |  |
Variable Interest Entity, Primary Beneficiary | Noncurrent Liabilities | SOUTHWESTERN ELECTRIC POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Securitization Bonds | 309.0 |  |  |
Variable Interest Entity, Primary Beneficiary | Noncurrent Liabilities | AEP TEXAS INC. | AEP Texas Restoration Funding |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Securitization Bonds | 102.0 | 126.0 |  |
Variable Interest Entity, Primary Beneficiary | Noncurrent Liabilities | APPALACHIAN POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Securitization Bonds | $ 91.0 | 120.0 |  |
Variable Interest Entity, Not Primary Beneficiary |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
AEP's ownership In OVEC | 43.47% |  |  |
Approximate OVEC generating capacity (MWs) | MW | 2,400 |  |  |
Outstanding Indebtedness | $ 997.0 | 1,100.0 |  |
Variable Interest Entity, Not Primary Beneficiary | Parent |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
AEP's ownership In OVEC | 39.17% |  |  |
Variable Interest Entity, Not Primary Beneficiary | SOUTHWESTERN ELECTRIC POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Billings from VIE | $ 194.4 | 185.1 | 192.5 |
Percentage of VIE sales of lignite produced | 50.00% |  |  |
Percentage of VIE debt guaranteed | 50.00% |  |  |
Percentage of VIE management fee received | 100.00% |  |  |
Dividends | $ 1.0 | 1.0 | 25.0 |
Variable Interest Entity, Not Primary Beneficiary | INDIANA MICHIGAN POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Billings from VIE | $ 187.6 | 178.4 | 192.4 |
Power participation ratio | 7.85% |  |  |
Outstanding Indebtedness | $ 78.0 | 84.0 |  |
Variable Interest Entity, Not Primary Beneficiary | AEP TEXAS INC. |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Billings from VIE | 242.6 | 228.5 | 236.8 |
Variable Interest Entity, Not Primary Beneficiary | APPALACHIAN POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Billings from VIE | $ 335.3 | 324.9 | 347.5 |
Power participation ratio | 15.69% |  |  |
Outstanding Indebtedness | $ 156.0 | 168.0 |  |
Variable Interest Entity, Not Primary Beneficiary | OHIO POWER COMPANY |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Billings from VIE | $ 283.4 | 269.5 | $ 272.5 |
Power acquired, solid oxide fuel cells | MW | 100 |  |  |
Construction work in progress | $ 457.0 |  |  |
Borrowings | $ 456.0 |  |  |
AEP's ownership In OVEC | 4.30% |  |  |
Power participation ratio | 19.93% |  |  |
Outstanding Indebtedness | $ 199.0 | $ 213.0 |  |
Variable Interest Entity, Not Primary Beneficiary | OHIO POWER COMPANY | Forecast [Member] |  |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |  |
Power acquired, option, solid oxide fuel cells | GW |  |  |  | 1

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