v3.26.3
FAIR VALUE MEASUREMENTS - Changes in Fair Value (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]        
Beginning Balance $ 380 $ 383 $ 259 $ 166
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets) 123 45 245 155
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date (28) 13 (24) 31
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income 4 1 14 14
Settlements (192) (132) (463) (277)
Transfers into Level 3 5 7 3 1
Transfers out of Level 3 0 (5) (2) (3)
Changes in Fair Value Allocated to Regulated Jurisdiction 81 15 341 240
Ending Balance 373 327 373 327
APCo        
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]        
Beginning Balance 171 108 81 35
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets) 44 15 162 49
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date 0 0 0 0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income 0 0 0 0
Settlements (69) (34) (243) (84)
Transfers into Level 3 0 0 0 0
Transfers out of Level 3 0 0 0 0
Changes in Fair Value Allocated to Regulated Jurisdiction 37 2 183 91
Ending Balance 183 91 183 91
I&M        
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]        
Beginning Balance 22 12 9 6
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets) 6 4 12 13
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date 0 0 0 0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income 0 0 0 0
Settlements (8) (7) (21) (19)
Transfers into Level 3 0 0 0 0
Transfers out of Level 3 0 0 0 0
Changes in Fair Value Allocated to Regulated Jurisdiction 3 2 23 11
Ending Balance 23 11 23 11
OPCo        
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]        
Beginning Balance (28) (48) (33) (47)
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets) 0 0 1 0
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date 0 0 0 0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income 0 0 0 0
Settlements 0 1 3 5
Transfers into Level 3 0 0 0 0
Transfers out of Level 3 0 0 0 0
Changes in Fair Value Allocated to Regulated Jurisdiction 6 3 7 (2)
Ending Balance (22) (44) (22) (44)
PSO        
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]        
Beginning Balance 43 97 41 20
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets) 25 14 47 38
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date 0 0 0 0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income 0 0 0 0
Settlements (42) (45) (88) (58)
Transfers into Level 3 0 0 0 0
Transfers out of Level 3 0 0 0 0
Changes in Fair Value Allocated to Regulated Jurisdiction 15 (1) 41 65
Ending Balance 41 65 41 65
SWEPCo        
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]        
Beginning Balance 42 69 35 17
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets) 33 10 18 42
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date 0 0 0 0
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income 0 0 0 0
Settlements (48) (30) (52) (59)
Transfers into Level 3 0 0 0 0
Transfers out of Level 3 0 0 0 0
Changes in Fair Value Allocated to Regulated Jurisdiction 16 8 42 57
Ending Balance $ 43 $ 57 $ 43 $ 57