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Rate Matters Regulated Operations (Details) - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Dec. 31, 2021
Public Utilities, General Disclosures [Line Items]      
Net Investment $ 69,813.1   $ 66,001.3
Regulatory Assets, Noncurrent 3,877.5   4,142.3
Other Asset Impairment Charges 24.9 $ 0.0  
Regulatory Assets, Current 1,137.1   647.8
AEP Texas Inc. [Member]      
Public Utilities, General Disclosures [Line Items]      
Net Investment 11,311.7   10,635.4
Regulatory Assets, Noncurrent 243.9   275.2
AEP Transmission Co [Member]      
Public Utilities, General Disclosures [Line Items]      
Net Investment 12,742.6   11,935.7
Regulatory Assets, Noncurrent 2.6   8.5
Appalachian Power Co [Member]      
Public Utilities, General Disclosures [Line Items]      
Net Investment 12,163.6   11,804.3
Regulatory Assets, Noncurrent 970.3   757.6
Other Asset Impairment Charges 24.9 $ 0.0  
Regulatory Assets, Current 404.0   201.3
Indiana Michigan Power Co [Member]      
Public Utilities, General Disclosures [Line Items]      
Net Investment 7,389.4   7,310.9
Regulatory Assets, Noncurrent 422.5   410.9
Regulatory Assets, Current 25.4   6.4
Ohio Power Co [Member]      
Public Utilities, General Disclosures [Line Items]      
Net Investment 8,396.0   7,963.0
Regulatory Assets, Noncurrent 270.8   293.0
Public Service Co Of Oklahoma [Member]      
Public Utilities, General Disclosures [Line Items]      
Net Investment 5,534.2   4,802.8
Regulatory Assets, Noncurrent 606.2   1,037.4
Regulatory Assets, Current 178.7   194.6
Public Service Co Of Oklahoma [Member] | Northeastern Plant, Unit 3 | Generating Units Probable of Abandonment [Member]      
Public Utilities, General Disclosures [Line Items]      
Net Investment 143.7    
Accelerated Depreciation Regulatory Asset 141.4    
Cost of Removal Regulatory Liability [1] $ 20.2    
Expected Retirement Date [2] 2026    
Depreciation [3] $ 14.9    
Southwestern Electric Power Co [Member]      
Public Utilities, General Disclosures [Line Items]      
Net Investment 8,159.9   7,400.1
Regulatory Assets, Noncurrent 992.4   1,005.3
Net Under-Recovered Fuel Costs 236.0    
Regulatory Assets, Current 333.8   143.9
Southwestern Electric Power Co [Member] | Dolet Hills Power Station and Related Fuel Operations      
Public Utilities, General Disclosures [Line Items]      
Share of Net Investment in Dolet Hills Power Station 113.0    
Southwestern Electric Power Co [Member] | Dolet Hills Power Station and Related Fuel Operations | Arkansas      
Public Utilities, General Disclosures [Line Items]      
Recovery of 2021 Dolet Hills Fuel Costs 20.0    
Southwestern Electric Power Co [Member] | Dolet Hills Power Station and Related Fuel Operations | Louisiana Jurisdiction [Member]      
Public Utilities, General Disclosures [Line Items]      
Recovery of 2021 Dolet Hills Fuel Costs 20.0    
Approved Deferral of Dolet Hills Fuel Costs 30.0    
Recommended Disallowance from Staff or Intervenors 72.0    
Southwestern Electric Power Co [Member] | Pirkey Power Plant and Related Fuel Operations      
Public Utilities, General Disclosures [Line Items]      
Share of Net Investment in Pirkey Power Plant 216.0    
Pirkey Power Plant and Sabine Unbilled Fixed Costs 49.0    
Southwestern Electric Power Co [Member] | Pirkey Generating Station (Unit No. 1) | Generating Units Probable of Abandonment [Member]      
Public Utilities, General Disclosures [Line Items]      
Net Investment 65.0    
Accelerated Depreciation Regulatory Asset 150.7    
Cost of Removal Regulatory Liability $ 39.6    
Expected Retirement Date [4] 2023    
Depreciation [3] $ 12.5    
Southwestern Electric Power Co [Member] | Welsh Plant Unit 1 and 3 | Generating Units Probable of Abandonment [Member]      
Public Utilities, General Disclosures [Line Items]      
Net Investment 432.3    
Accelerated Depreciation Regulatory Asset 75.7    
Cost of Removal Regulatory Liability [5] $ 58.2    
Expected Retirement Date [6] 2028    
Depreciation [3] $ 39.8    
Southwestern Electric Power Co [Member] | Welsh Plant Unit 2      
Public Utilities, General Disclosures [Line Items]      
Impairment Charge Welsh Plant, Unit 2 7.0    
Southwestern Electric Power Co [Member] | Dolet Hills Power Station | Arkansas      
Public Utilities, General Disclosures [Line Items]      
Other Asset Impairment Charges 2.0    
Southwestern Electric Power Co [Member] | Dolet Hills Power Station | Texas      
Public Utilities, General Disclosures [Line Items]      
Other Asset Impairment Charges 12.0    
Regulatory Assets Pending Final Regulatory Approval [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 941.2   1,048.6
Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 57.5   41.2
Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 166.7   105.1
Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 1.9   3.7
Regulatory Assets Pending Final Regulatory Approval [Member] | Ohio Power Co [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 32.6   3.8
Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 24.4   14.2
Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 656.6   880.6
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Plant Retirement Costs - Unrecovered Plant [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 35.2   35.2
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Dolet Hills Power Station Accelerated Depreciation [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 54.7   72.3
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 21.2   9.2
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | February 2021 Severe Storm Fuel Costs      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent [7] 126.1   430.2
Regulatory Assets, Current 37.0   63.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Pirkey Power Plant Accelerated Depreciation      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 150.7   87.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Welsh Unit 1 and 3 Accelerated Depreciation      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 75.7   45.9
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Dolet Hills Power Station Fuel Costs - Louisiana      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 31.8   30.9
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | Mobile Generation Lease Payments      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 9.2   0.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | COVID-19 - Virginia      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 7.0   6.8
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 0.1   0.1
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Dolet Hills Power Station Accelerated Depreciation [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 54.7   72.3
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Plant Retirement Costs - Unrecovered Plant, Louisiana      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 35.2   35.2
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 4.9   2.4
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | February 2021 Severe Storm Fuel Costs      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent [8] 126.1   430.2
Regulatory Assets, Current 37.0   63.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Pirkey Power Plant Accelerated Depreciation      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 150.7   87.0
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Welsh Unit 1 and 3 Accelerated Depreciation      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 75.7   45.9
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Dolet Hills Power Station Fuel Costs - Louisiana      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 31.8   30.9
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Dolet Hills Power Station      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 55.0    
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | COVID-19      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 8.7   11.2
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Plant Retirement Costs - Asset Retirement Obligation Costs [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 25.9   25.9
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Storm Related Costs [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 306.5   241.8
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 42.4   41.8
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Renewable Energy Portfolio Standards Costs      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 0.0   2.1
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | 2017-2019 Virginia Triennial Under-Earnings [Domain]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 37.0   0.0
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | 2020-2022 Virginia Triennial Under-Earnings [Domain]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 25.3   15.1
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | COVID-19      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 3.8   2.1
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | Storm Related Costs [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 27.0   22.4
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 8.2   7.4
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | Texas Retail Electric Provider Bad Debt Expense      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 4.1   4.1
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] | Vegetation Management Programs      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 5.2   5.2
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | Plant Retirement Costs - Asset Retirement Obligation Costs [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 25.9   25.9
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | Storm Related Costs [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 69.9   53.7
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 1.6   1.5
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | Renewable Energy Portfolio Standards Costs      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 0.0   2.1
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | 2017-2019 Virginia Triennial Under-Earnings [Domain]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 37.0   0.0
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] | 2020-2022 Virginia Triennial Under-Earnings [Domain]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 25.3   15.1
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] | COVID-19      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 0.1   1.7
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 1.7   1.9
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Ohio Power Co [Member] | Storm Related Costs [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 32.5   3.8
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Ohio Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 0.1   0.0
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member] | Storm Related Costs [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 24.3   13.9
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 0.1   0.3
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Asset Retirement Obligation - Louisiana [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 11.3   10.3
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Other Regulatory Assets Not Yet Being Recovered [Member]      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent 14.9   18.4
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] | Storm Related Costs - Louisiana      
Public Utilities, General Disclosures [Line Items]      
Regulatory Assets, Noncurrent $ 151.3   $ 148.0
[1] Includes Northeastern Plant, Unit 4, which was retired in 2016. Removal of Northeastern Plant, Unit 4, will be performed with Northeastern Plant, Unit 3, after retirement.
[2] Northeastern Plant, Unit 3 is currently being recovered through 2040.
[3] Represents the amount of annual depreciation that has been collected from customers over the prior 12-month period.
[4] Pirkey Plant is currently being recovered through 2025 in the Louisiana jurisdiction and through 2045 in the Arkansas and Texas jurisdictions
[5] Includes Welsh Plant, Unit 2, which was retired in 2016. Removal of Welsh Plant, Unit 2, will be performed with Welsh Plant, Units 1 and 3, after retirement.
[6] Unit 1 is being recovered through 2027 in the Louisiana jurisdiction and through 2037 in the Arkansas and Texas jurisdictions. Unit 3 is being recovered through 2032 in the Louisiana jurisdiction and through 2042 in the Arkansas and Texas jurisdictions.
[7] Includes $37 million and $63 million of unrecovered winter storm fuel costs recorded as a current regulatory asset as of September 30, 2022 and December 31, 2021, respectively.
[8] Includes $37 million and $63 million of unrecovered winter storm fuel costs recorded as a current regulatory asset as of September 30, 2022 and December 31, 2021, respectively.