v3.26.1
DERIVATIVES AND HEDGING - Schedule of Offsetting Assets and Liabilities (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Total Assets    
Gross Amounts Recognized $ 1,999 $ 1,357
Current Risk Management Assets 533 352
Long-term Risk Management Assets 235 265
Total Risk Management Assets 768 617
Total Liabilities    
Gross Amounts Recognized 1,458 970
Current Risk Management Liabilities 152 132
Long-term Risk Management Liabilities 175 178
Total Risk Management Liabilities 327 310
Total MTM Derivative Contract Net Assets (Liabilities) 441 307
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Total Liabilities    
Gross Amounts Recognized 946 532
Gross Amounts Offset (794) (400)
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Total Liabilities    
Gross Amounts Recognized 512 438
Gross Amounts Offset (337) (260)
Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Total Assets    
Gross Amounts Recognized 1,374 776
Gross Amounts Offset (841) (424)
Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Total Assets    
Gross Amounts Recognized 625 581
Gross Amounts Offset (390) (316)
AEP Texas    
Total Assets    
Gross Amounts Recognized 1 0
Current Risk Management Assets 0 0
Long-term Risk Management Assets 0 0
Total Risk Management Assets 0 0
Total Liabilities    
Gross Amounts Recognized 0 0
Current Risk Management Liabilities 0 0
Long-term Risk Management Liabilities 0 0
Total Risk Management Liabilities 0 0
Total MTM Derivative Contract Net Assets (Liabilities) 0 0
AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Total Liabilities    
Gross Amounts Recognized 0 0
Gross Amounts Offset 0 0
AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Total Liabilities    
Gross Amounts Recognized 0 0
Gross Amounts Offset 0 0
AEP Texas | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Total Assets    
Gross Amounts Recognized 1 0
Gross Amounts Offset (1) 0
AEP Texas | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Total Assets    
Gross Amounts Recognized 0 0
Gross Amounts Offset 0 0
APCo    
Total Assets    
Gross Amounts Recognized 175 84
Current Risk Management Assets 171 81
Long-term Risk Management Assets 0 1
Total Risk Management Assets 171 82
Total Liabilities    
Gross Amounts Recognized 16 6
Current Risk Management Liabilities 10 3
Long-term Risk Management Liabilities 2 0
Total Risk Management Liabilities 12 3
Total MTM Derivative Contract Net Assets (Liabilities) 159 79
APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Total Liabilities    
Gross Amounts Recognized 14 5
Gross Amounts Offset (4) (2)
APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Total Liabilities    
Gross Amounts Recognized 2 1
Gross Amounts Offset 0 (1)
APCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Total Assets    
Gross Amounts Recognized 175 82
Gross Amounts Offset (4) (1)
APCo | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Total Assets    
Gross Amounts Recognized 0 2
Gross Amounts Offset 0 (1)
I&M    
Total Assets    
Gross Amounts Recognized 60 24
Current Risk Management Assets 22 10
Long-term Risk Management Assets 0 0
Total Risk Management Assets 22 10
Total Liabilities    
Gross Amounts Recognized 44 14
Current Risk Management Liabilities 0 0
Long-term Risk Management Liabilities 0 0
Total Risk Management Liabilities 0 0
Total MTM Derivative Contract Net Assets (Liabilities) 22 10
I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Total Liabilities    
Gross Amounts Recognized 41 13
Gross Amounts Offset (41) (13)
I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Total Liabilities    
Gross Amounts Recognized 3 1
Gross Amounts Offset (3) (1)
I&M | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Total Assets    
Gross Amounts Recognized 58 23
Gross Amounts Offset (36) (13)
I&M | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Total Assets    
Gross Amounts Recognized 2 1
Gross Amounts Offset (2) (1)
OPCo    
Total Assets    
Gross Amounts Recognized 1 0
Current Risk Management Assets 0 0
Long-term Risk Management Assets 0 0
Total Risk Management Assets 0 0
Total Liabilities    
Gross Amounts Recognized 28 33
Current Risk Management Liabilities 4 5
Long-term Risk Management Liabilities 24 28
Total Risk Management Liabilities 28 33
Total MTM Derivative Contract Net Assets (Liabilities) (28) (33)
OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Total Liabilities    
Gross Amounts Recognized 4 5
Gross Amounts Offset 0 0
OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Total Liabilities    
Gross Amounts Recognized 24 28
Gross Amounts Offset 0 0
OPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Total Assets    
Gross Amounts Recognized 1 0
Gross Amounts Offset (1) 0
OPCo | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Total Assets    
Gross Amounts Recognized 0 0
Gross Amounts Offset 0 0
PSO    
Total Assets    
Gross Amounts Recognized 44 44
Current Risk Management Assets 43 42
Long-term Risk Management Assets 0 0
Total Risk Management Assets 43 42
Total Liabilities    
Gross Amounts Recognized 29 30
Current Risk Management Liabilities 22 27
Long-term Risk Management Liabilities 6 1
Total Risk Management Liabilities 28 28
Total MTM Derivative Contract Net Assets (Liabilities) 15 14
PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Total Liabilities    
Gross Amounts Recognized 23 29
Gross Amounts Offset (1) (2)
PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Total Liabilities    
Gross Amounts Recognized 6 1
Gross Amounts Offset 0 0
PSO | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Total Assets    
Gross Amounts Recognized 44 44
Gross Amounts Offset (1) (2)
PSO | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Total Assets    
Gross Amounts Recognized 0 0
Gross Amounts Offset 0 0
SWEPCo    
Total Assets    
Gross Amounts Recognized 43 37
Current Risk Management Assets 42 35
Long-term Risk Management Assets 0 0
Total Risk Management Assets 42 35
Total Liabilities    
Gross Amounts Recognized 13 13
Current Risk Management Liabilities 10 9
Long-term Risk Management Liabilities 3 2
Total Risk Management Liabilities 13 11
Total MTM Derivative Contract Net Assets (Liabilities) 29 24
SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent    
Total Liabilities    
Gross Amounts Recognized 10 11
Gross Amounts Offset 0 (2)
SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent    
Total Liabilities    
Gross Amounts Recognized 3 2
Gross Amounts Offset 0 0
SWEPCo | Location, Statement of Financial Position, Balance [Axis]: us-gaap:PrepaidExpenseAndOtherAssetsCurrent    
Total Assets    
Gross Amounts Recognized 43 37
Gross Amounts Offset (1) (2)
SWEPCo | Location, Statement of Financial Position, Balance [Axis]: aeptexas:DeferredChargesAndOtherNoncurrentAssets    
Total Assets    
Gross Amounts Recognized 0 0
Gross Amounts Offset $ 0 $ 0