v3.26.1
Fair Value Measurements (Net Change in the Assets and Liabilities Measured at Fair Value on a Recurring Basis and Included in the Level 3 Fair Value Category) (Detail) - Commodity - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]        
Beginning balance $ 512 $ 269 $ 627 $ 384
Total realized and unrealized gains (losses):        
Operating revenue (20) (3) (30) 10
Purchased electric capacity 0 0 (7) 0
Included in earnings $ 240 $ 143 $ 252 $ 118
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Electric fuel and other energy-related purchases Electric fuel and other energy-related purchases Electric fuel and other energy-related purchases Electric fuel and other energy-related purchases
Purchased gas $ (3) $ 0 $ 0 $ 0
Included in regulatory assets/liabilities 245 150 163 43
Settlements (254) (153) (296) (149)
Purchases 210 8 221 8
Ending balance 930 414 930 414
Virginia Electric and Power Company        
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]        
Beginning balance 134 26 208 68
Total realized and unrealized gains (losses):        
Purchased electric capacity 0 0 (7) 0
Included in earnings 244 143 244 116
Included in regulatory assets/liabilities 181 145 100 113
Settlements (244) (143) (241) (126)
Purchases 0 8 11 8
Ending balance $ 315 $ 179 $ 315 $ 179