v3.26.3
Investments (Selected Information Regarding Equity and Fixed Income Securities) (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Schedule of Available-for-sale Securities [Line Items]        
Proceeds from sales $ 531 $ 869 $ 2,839 $ 2,563
Realized gains [1] 44 18 76 36
Realized losses [1] 39 15 81 57
Virginia Electric and Power Company        
Schedule of Available-for-sale Securities [Line Items]        
Proceeds from sales 396 489 1,979 1,412
Realized gains [2] 24 12 48 26
Realized losses [2] $ 23 $ 11 $ 51 $ 40
[1] Includes realized gains and losses recorded to the nuclear decommissioning trust regulatory liability.
[2] Includes realized gains and losses recorded to the nuclear decommissioning trust regulatory liability.