v3.26.3
DERIVATIVES AND HEDGING - Schedule of Location and Fair Value of Derivative Assets and Liabilities (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Derivative [Line Items]    
Total Assets $ 2,233 $ 1,357
Total Liabilities 1,693 970
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 540 387
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 1,123 532
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 570 438
Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 1,549 776
Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 684 581
AEP Texas    
Derivative [Line Items]    
Total Assets 2 0
Total Liabilities 0 0
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 2 0
AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 2 0
AEP Texas | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
APCo    
Derivative [Line Items]    
Total Assets 191 84
Total Liabilities 20 6
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 171 78
APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 19 5
APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 1 1
APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 190 82
APCo | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 1 2
I&M    
Derivative [Line Items]    
Total Assets 51 24
Total Liabilities 33 14
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 18 10
I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 33 13
I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 1
I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 51 23
I&M | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 1
OPCo    
Derivative [Line Items]    
Total Assets 1 0
Total Liabilities 22 33
Total MTM Derivative Contract Net Assets (Liabilities) Recognized (21) (33)
OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 3 5
OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 19 28
OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 1 0
OPCo | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
PSO    
Derivative [Line Items]    
Total Assets 42 44
Total Liabilities 34 30
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 8 14
PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 29 29
PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 5 1
PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 42 44
PSO | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
SWEPCo    
Derivative [Line Items]    
Total Assets 44 37
Total Liabilities 12 13
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 32 24
SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 10 11
SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 2 2
SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 44 37
SWEPCo | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Not Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 1,091 500
Commodity | Not Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 549 420
Commodity | Not Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 1,473 720
Commodity | Not Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 630 518
Commodity | Not Designated as Hedging Instrument | AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Not Designated as Hedging Instrument | AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Not Designated as Hedging Instrument | AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 2 0
Commodity | Not Designated as Hedging Instrument | AEP Texas | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Not Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 19 5
Commodity | Not Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 1 1
Commodity | Not Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 190 82
Commodity | Not Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 1 2
Commodity | Not Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 33 13
Commodity | Not Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 1
Commodity | Not Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 51 23
Commodity | Not Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 1
Commodity | Not Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 3 5
Commodity | Not Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 19 28
Commodity | Not Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 1 0
Commodity | Not Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Not Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 29 29
Commodity | Not Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 5 1
Commodity | Not Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 42 44
Commodity | Not Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Not Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 10 11
Commodity | Not Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 2 2
Commodity | Not Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 44 37
Commodity | Not Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 14 16
Commodity | Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 9 5
Commodity | Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 76 56
Commodity | Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 54 63
Commodity | Designated as Hedging Instrument | AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | AEP Texas | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: aep:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
Interest Rate (USD) | Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 18 16
Interest Rate (USD) | Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 12 13
Interest Rate (USD) | Designated as Hedging Instrument | AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Interest Rate (USD) | Designated as Hedging Instrument | AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Interest Rate (USD) | Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Interest Rate (USD) | Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Interest Rate (USD) | Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Interest Rate (USD) | Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Interest Rate (USD) | Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Interest Rate (USD) | Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Interest Rate (USD) | Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Interest Rate (USD) | Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Interest Rate (USD) | Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Interest Rate (USD) | Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities $ 0 $ 0