v3.26.1
DERIVATIVES AND HEDGING - Schedule of Location and Fair Value of Derivative Assets and Liabilities (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Derivative [Line Items]    
Total Assets $ 1,999 $ 1,357
Total Liabilities 1,458 970
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 541 387
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 946 532
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 512 438
Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 1,374 776
Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 625 581
AEP TEXAS INC.    
Derivative [Line Items]    
Total Assets 1 0
Total Liabilities 0 0
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 1 0
AEP TEXAS INC. | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
AEP TEXAS INC. | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
AEP TEXAS INC. | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 1 0
AEP TEXAS INC. | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
APCo    
Derivative [Line Items]    
Total Assets 175 84
Total Liabilities 16 6
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 159 78
APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 14 5
APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 2 1
APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 175 82
APCo | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 2
I&M    
Derivative [Line Items]    
Total Assets 60 24
Total Liabilities 44 14
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 16 10
I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 41 13
I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 3 1
I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 58 23
I&M | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 2 1
OPCo    
Derivative [Line Items]    
Total Assets 1 0
Total Liabilities 28 33
Total MTM Derivative Contract Net Assets (Liabilities) Recognized (27) (33)
OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 4 5
OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 24 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]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
PSO    
Derivative [Line Items]    
Total Assets 44 44
Total Liabilities 29 30
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 15 14
PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 23 29
PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 6 1
PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 44 44
PSO | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 0
SWEPCo    
Derivative [Line Items]    
Total Assets 43 37
Total Liabilities 13 13
Total MTM Derivative Contract Net Assets (Liabilities) Recognized 30 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 3 2
SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 43 37
SWEPCo | Location, Statement of Financial Position, Balance [Axis]: aeptexas: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 914 500
Commodity | Not Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 489 420
Commodity | Not Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 1,296 720
Commodity | Not Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 568 518
Commodity | Not Designated as Hedging Instrument | AEP TEXAS INC. | 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 INC. | 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 INC. | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 1 0
Commodity | Not Designated as Hedging Instrument | AEP TEXAS INC. | Location, Statement of Financial Position, Balance [Axis]: aeptexas: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 14 5
Commodity | Not Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 2 1
Commodity | Not Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 175 82
Commodity | Not Designated as Hedging Instrument | APCo | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 0 2
Commodity | Not Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 41 13
Commodity | Not Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 3 1
Commodity | Not Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 58 23
Commodity | Not Designated as Hedging Instrument | I&M | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 2 1
Commodity | Not Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 4 5
Commodity | Not Designated as Hedging Instrument | OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 24 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]: aeptexas: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 23 29
Commodity | Not Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 6 1
Commodity | Not Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 44 44
Commodity | Not Designated as Hedging Instrument | PSO | Location, Statement of Financial Position, Balance [Axis]: aeptexas: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 3 2
Commodity | Not Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 43 37
Commodity | Not Designated as Hedging Instrument | SWEPCo | Location, Statement of Financial Position, Balance [Axis]: aeptexas: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 15 16
Commodity | Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 13 5
Commodity | Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 78 56
Commodity | Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Derivative [Line Items]    
Total Assets 57 63
Commodity | Designated as Hedging Instrument | AEP TEXAS INC. | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | AEP TEXAS INC. | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 0 0
Commodity | Designated as Hedging Instrument | AEP TEXAS INC. | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Derivative [Line Items]    
Total Assets 0 0
Commodity | Designated as Hedging Instrument | AEP TEXAS INC. | Location, Statement of Financial Position, Balance [Axis]: aeptexas: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]: aeptexas: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]: aeptexas: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]: aeptexas: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]: aeptexas: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]: aeptexas: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 17 16
Interest Rate (USD) | Designated as Hedging Instrument | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Derivative [Line Items]    
Total Liabilities 10 13
Interest Rate (USD) | Designated as Hedging Instrument | AEP TEXAS INC. | 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 INC. | 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