Significant Accounting Policies (Schedule of Supplemental Cash Flow Information) (Parenthetical) (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Schedule Of Supplemental Cash Flow Information [Line Items]
Financing leases	$ 51	$ 40
Operating leases	145	239
Virginia Electric and Power Company
Schedule Of Supplemental Cash Flow Information [Line Items]
Financing leases	42	36
Operating leases	$ 129	$ 206