Derivatives and Hedge Accounting Activities (Schedule of Derivatives not Designated as Hedging Instruments) (Detail) - Derivatives Not Designated as Hedging Instruments - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[1],[2]	$ (73)	$ 234
Virginia Electric and Power Company
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[3],[4]	16	(46)
Commodity Contract | Operating Revenue
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[1],[2]	(330)	(41)
Commodity Contract | Operating Revenue | Virginia Electric and Power Company
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[3],[4]	(41)	(2)
Commodity Contract | Purchased Gas
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[1],[2]	2	0
Commodity Contract | Electric Fuel and Other Energy-Related Purchases
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[1],[2]	59	(44)
Commodity Contract | Electric Fuel and Other Energy-Related Purchases | Virginia Electric and Power Company
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[3],[4]	57	(44)
Interest Rate Contract | Interest And Related Charges
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[1],[2]	$ 196	$ 319

[1] Excludes amounts related to foreign currency exchange rate derivatives that are deferred to plant under construction within property, plant and equipment that will begin to amortize once the CVOW Commercial Project is placed in service

[2] Includes derivative activity amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in Dominion Energy’s Consolidated Statements of Income

[3] Excludes amounts related to foreign currency exchange rate derivatives that are deferred to plant under construction within property, plant                       and equipment that will begin to amortize once the CVOW Commercial Project is placed in service.

[4] Includes derivative activity amortized out of regulatory assets/liabilities. Amounts deferred into regulatory assets/liabilities have no associated effect in Virginia Power’s Consolidated Statements of Income.