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		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[1],[2]	$ (8)	$ (285)	$ 127	$ (340)
Virginia Electric and Power Company
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[3],[4]	58	23	111	(20)
Commodity Contract | Operating Revenue
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[1],[2]	(306)	(334)	(908)	(521)
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]	(108)	(19)	(237)	(25)
Commodity Contract | Purchased Gas
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[1],[2]	1	25	6	32
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]	205	44	401	7
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]	166	42	348	5
Interest Rate Contract | Interest And Related Charges
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivatives	[1],[2]	$ 92	$ (20)	$ 628	$ 142

[1] Excludes amounts related to foreign currency exchange rate derivatives that are deferred to plant under construction within property, plant and equipment and regulatory assets/liabilities 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 and regulatory assets/liabilities 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.