Significant Accounting Policies (Narrative) (Detail) $ in Millions	1 Months Ended	3 Months Ended
	May 31, 2024 Station	Jun. 30, 2024 USD ($)
Asset Retirement Obligations [Line Items]
Number of stations maintains inactive or closed units expected to be subject to final rule | Station	19
Dominion Energy
Asset Retirement Obligations [Line Items]
Increase in asset retirement obligation		$ 1,100
Increase in regulatory assets		536
Increase in property, plant, and equipment		505
Virginia Power
Asset Retirement Obligations [Line Items]
Number of stations maintains inactive or closed units expected to be subject to final rule | Station	12
Increase in asset retirement obligation		420
Increase in regulatory assets		234
Increase in property, plant, and equipment		152
Increase in other deferred charges and other assets		$ 34