v3.25.2
Investments (Selected Information Regarding Equity and Fixed Income Securities) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Schedule of Available-for-sale Securities [Line Items]        
Proceeds from sales $ 763 $ 884 $ 1,694 $ 1,579
Realized gains [1] 7 27 18 59
Realized losses [1] 22 34 42 72
Virginia Electric and Power Company        
Schedule of Available-for-sale Securities [Line Items]        
Proceeds from sales 355 602 923 1,073
Realized gains [2] 5 16 14 39
Realized losses [2] $ 14 $ 22 $ 29 $ 45
[1] Includes realized gains and losses recorded to the nuclear decommissioning trust regulatory liabilities.
[2] Includes realized gains and losses recorded to the nuclear decommissioning trust regulatory liabilities.