Significant Accounting Policies (Schedule of Supplemental Cash Flow Information) (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Supplemental Cash Flow Information [Line Items]
Financing leases	$ 93	$ 44	$ 34
Operating leases	140	211	110
Virginia Electric and Power Company
Schedule Of Supplemental Cash Flow Information [Line Items]
Financing leases	77	30	26
Operating leases	$ 124	$ 173	$ 90