Operating Segments - Virginia Power (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Gain (loss) on investments	$ (116)	$ 294
Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Gain (loss) on investments	(11)	39
Operating Segments
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)	(151)	124
Gain (loss) on investments	(132)	266
Gain (loss) on investments, after tax	$ (95)	$ 202
Investment, Type [Extensible Enumeration]	Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]
Operating Segments | Corporate and Other
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)	$ (176)	$ (185)
After- tax net benefits (expenses) for specific items	(157)	(44)
Operating Segments | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Loss associated with severe weather events	82
Loss associated with severe weather events, after-tax	61
Share of costs not expected to be recovered from customers on the CVOW commercial project	23
Share of costs not expected to be recovered from customers on the CVOW commercial project, after tax	17
Gain (loss) on investments	(14)	37
Gain (loss) on investments, after tax	$ (11)	$ 27
Investment, Type [Extensible Enumeration]	Nuclear Decommissioning Trust Fund [Member]	Nuclear Decommissioning Trust Fund [Member]
Operating Segments | Virginia Electric and Power Company | Corporate and Other
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)	$ (79)	$ 41
After- tax net benefits (expenses) for specific items	$ (88)	$ 39