Income Taxes (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Income Taxes [Line Items]
Production tax credit	$ 14	$ 0
Income tax (benefit) expense from discontinued operations	(1)	$ 54
Maximum
Income Taxes [Line Items]
Income tax (benefit) expense from discontinued operations	1
Virginia Electric and Power Company
Income Taxes [Line Items]
Production tax credit	19
Dominion Energy
Income Taxes [Line Items]
Effective tax rate income tax net benefit	18
Remeasurement of unrecognized tax benefit	$ 30

Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal.

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+ Details