Acquisitions and Dispositions (Schedule of Results of Operations of Disposal Groups Reported As Discontinued Operations) (Detail) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Income tax expense (benefit) from discontinued operations		$ 0	$ (6,000,000)	$ 4,000,000	$ 5,000,000
Net income attributable to Dominion Energy		$ (3,000,000)	65,000,000	$ 15,000,000	119,000,000
Disposition of GTS Operations | Q-Pipe Group
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Operating revenue			62,000,000		188,000,000
Operating expense			24,000,000		52,000,000
Other income	[1]		26,000,000		27,000,000
Interest and related charges			7,000,000		17,000,000
Income before income taxes	[2]		57,000,000		146,000,000
Income tax expense (benefit) from discontinued operations			12,000,000		29,000,000
Net income attributable to Dominion Energy			$ 45,000,000		$ 117,000,000

[1] Includes a $25 million benefit associated with the termination of the Q-Pipe Transaction in the third quarter of 2021.

[2] Excludes $18 million income tax benefit recorded in the third quarter of 2021 associated with the GT&S Transaction.