Acquisitions and Dispositions - (Schedule of Results of Operations of Disposal Groups Reported As Discontinued Operations) (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Income tax expense (benefit)		$ (1)	$ 54
Net income (loss) attributable to Dominion Energy		$ (1)	118
East Ohio | Enbridge
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Operating revenue	[1]		229
Operating expense	[1],[2]		247
Other income (expense)	[1]		(17)
Interest and related charges	[1]		15
Income (loss) before income taxes	[1]		(50)
Income tax expense (benefit)	[1]		11
Net income (loss) attributable to Dominion Energy	[1],[3]		(61)
PSNC | Enbridge
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Operating revenue	[1]		298
Operating expense	[1],[2]		158
Other income (expense)	[1]		3
Interest and related charges	[1]		14
Income (loss) before income taxes	[1]		129
Income tax expense (benefit)	[1]		31
Net income (loss) attributable to Dominion Energy	[1],[3]		98
Questar Gas and Wexpro | Enbridge
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Operating revenue	[1]		695
Operating expense	[1],[2]		575
Other income (expense)	[1]		1
Interest and related charges	[1]		16
Income (loss) before income taxes	[1]		105
Income tax expense (benefit)	[1]		84
Net income (loss) attributable to Dominion Energy	[1],[3]		21
Other Sales
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Operating revenue			0
Operating expense	[2]		1
Other income (expense)			0
Interest and related charges			0
Income (loss) before income taxes			(1)
Income tax expense (benefit)			0
Net income (loss) attributable to Dominion Energy	[3]		$ (1)

[1] Represents amounts attributable to Dominion Energy prior to the closing of the East Ohio Transaction which closed on March 6, 2024.

[2] East Ohio Transaction includes a charge of $45 million ($33 million after-tax) associated with an increase to certain pension retirement benefits attributable to a plan amendment and a contribution to the defined contribution employee savings plan. See Note 20 for further information on these transactions.

[3] Excludes $(69) million of income tax expense (benefit) attributable to consolidated state adjustments for the three months ended March 31, 2024.