Operating Segments - Dominion Energy (Narrative) (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Gain (loss) on investments	$ (556)	$ 364
Operating Segments
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)	(1,500)	(314)
Operating Segments | Nuclear Decommissioning Trust Funds
Segment Reporting Information [Line Items]
Gain (loss) on investments	(579)	328
Gain (loss) on investments, after tax	(450)	256
Corporate and Other | Operating Segments
Segment Reporting Information [Line Items]
After- tax net benefits (expenses)	(1,500)	(358)
After- tax net benefits (expenses) for specific items	(1,400)	(228)
Contracted Assets | Operating Segments
Segment Reporting Information [Line Items]
Loss associated with sale of kewaunee	649
Loss associated with sale of kewaunee, after tax	513
Loss related to economic hedging activities	126	169
Loss related to economic hedging activities after tax	91	127
Charge associated with revision in estimated recovery of spent nuclear fuel costs associated with the decommissioning of Kewaunee		44
Charge associated with revision in estimated recovery of spent nuclear fuel costs associated with the decommissioning of Kewaunee, after tax		35
Contracted Assets | Operating Segments | Nuclear Decommissioning Trust Funds
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax	(392)	226
Dominion Energy Virginia | Operating Segments
Segment Reporting Information [Line Items]
Charge associated with storm damage and service restoration	94	68
Charge associated with storm damage and service restoration, after tax	70	50
Charge for amortization of a regulatory asset, 2021 Triennial Review	122
Charge for amortization of a regulatory asset, 2021 Triennial Review, after tax	91
Charge in connection with proposed comprehensive settlement agreement for fuel expenses	191
Charge in connection with proposed comprehensive settlement agreement for fuel expenses, after-tax	142
Charge for RGGI compliance cost	180
Charge for RGGI compliance cost, after tax	134
Charges for Dismantling cost	42
Charges for Dismantling cost, after tax	31
Benefit for change in CCRO reserve		130
Benefit for change in CCRO reserve, after tax		97
Charges associated with budget process related to customer arrears		77
Charges associated with budget process related to customer arrears, after tax		57
Loss from unbilled revenue reduction		151
Loss from unbilled revenue reduction, after tax		112
Dominion Energy Virginia | Operating Segments | Nuclear Decommissioning Trust Funds
Segment Reporting Information [Line Items]
Gain (loss) on investments, after tax	$ (58)	30
Dominion Energy South Carolina Inc | Operating Segments
Segment Reporting Information [Line Items]
Charges associated with the settlement of the South Carolina electric base rate case		266
Charges associated with the settlement of the South Carolina electric base rate case, after tax		199
Litigation settlement expense		70
Litigation settlement expense, after tax		$ 53