v3.26.1
Investments (Selected Information Regarding Equity and Fixed Income Securities) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Schedule of Available-for-sale Securities [Line Items]        
Proceeds from sales $ 1,530 $ 763 $ 2,308 $ 1,694
Realized gains [1] 25 7 32 18
Realized losses [1] 25 22 42 42
Virginia Electric and Power Company        
Schedule of Available-for-sale Securities [Line Items]        
Proceeds from sales 1,031 355 1,583 923
Realized gains [2] 19 5 24 14
Realized losses [2] $ 19 $ 14 $ 28 $ 29
[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.