Acquisitions and Dispositions (Business Review Dispositions) (Narrative) (Detail) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
		Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023
Business Acquisition And Dispositions [Line Items]
Income tax expense (benefit)	[1]	$ 55	$ 55
Deferred income tax expense (benefit)		$ 82	(237)
East Ohio | Enbridge
Business Acquisition And Dispositions [Line Items]
Disposal group, total value of consideration					$ 6,600
Disposal group, cash consideration					4,300
Disposal group, indebtedness					$ 2,300
Disposal group, recognized a pre-tax loss			(97)
Disposal group, loss recorded after tax			(109)
Goodwill write-off			1,500
Deferred income tax expense (benefit)				$ 29
Questar Gas and Wexpro | Enbridge
Business Acquisition And Dispositions [Line Items]
Disposal group, recognized a pre-tax loss			78	236
Disposal group, loss recorded after tax			78	231
Income tax expense (benefit)			(5)
Deferred income tax expense (benefit)			$ (10)	$ 472

[1] The significant expense categories and amounts in the segment information presented above align with the segment-level information that is regularly provided to Dominion Energy’s CODM.