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RATE MATTERS - Regulatory Assets Subject to Securitization (Details) - APCo $ in Millions | Sep. 30, 2025 USD ($)
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Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | $ 2,527.6
Undepreciated Utility Plant Balances of Amos, Mitchell and Mountaineer (as of December 31, 2022) |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 1,704.2
ENEC Under-Recovery Regulatory Assets |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 412.4
Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024) |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 236.8
Deferred Storm O&M Expense Regulatory Assets |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 157.9
Upfront Financing Costs |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 16.3
APCo Portion |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 1,565.1
APCo Portion | Undepreciated Utility Plant Balances of Amos, Mitchell and Mountaineer (as of December 31, 2022) |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 1,145.5
APCo Portion | ENEC Under-Recovery Regulatory Assets |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 166.6
APCo Portion | Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024) |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 87.6
APCo Portion | Deferred Storm O&M Expense Regulatory Assets |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 155.0
APCo Portion | Upfront Financing Costs |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 10.4
WPCo Portion |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 962.5
WPCo Portion | Undepreciated Utility Plant Balances of Amos, Mitchell and Mountaineer (as of December 31, 2022) |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 558.7
WPCo Portion | ENEC Under-Recovery Regulatory Assets |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 245.8
WPCo Portion | Forecasted Undepreciated CCR and ELG Investments of Amos, Mitchell and Mountaineer (as of November 30, 2024) |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 149.2
WPCo Portion | Deferred Storm O&M Expense Regulatory Assets |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | 2.9
WPCo Portion | Upfront Financing Costs |
Regulatory Asset [Line Items] |
Regulatory asset, requested to be financed through securitization | $ 5.9

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- Definition Regulatory Asset, Requested To Be Financed Through Securitization + References No definition available. + Details
Name: | aep_RegulatoryAssetRequestedToBeFinancedThroughSecuritization
Namespace Prefix: | aep_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_RegulatoryAssetLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

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- Details
Name: | us-gaap_RegulatoryAssetAxis=aep_JurisdictionalPlantBalancesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_RegulatoryAssetAxis=aep_UnrecoveredENECBalanceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_RegulatoryAssetAxis=us-gaap_EnvironmentalRestorationCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_RegulatoryAssetAxis=us-gaap_StormCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_RegulatoryAssetAxis=aep_UpfrontFinancingCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_PublicUtilityAxis=aep_APCoPortionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_PublicUtilityAxis=aep_WPCoPortionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |