Derivatives and Hedge Accounting Activities (Fair Value of Derivatives) (Detail) - USD ($) $ in Millions		Sep. 30, 2023	Dec. 31, 2022
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	$ 231	$ 1,137
Derivative Asset, Noncurrent		1,415	1,039
Derivatives Assets		1,646	2,176
Derivative Liabilities, Current	[2]	469	778
Derivative Liabilities, Noncurrent		609	626
Derivative Liabilities		1,078	1,404
Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	55	765
Derivative Asset, Noncurrent		419	117
Derivatives Assets		474	882
Derivative Liabilities, Current	[2]	310	298
Derivative Liabilities, Noncurrent		160	158
Derivative Liabilities		470	456
Commodity Contract
Derivatives Fair Value [Line Items]
Derivative Asset, Current		159	532
Derivative Asset, Noncurrent		177	237
Derivative Liabilities, Current		350	700
Derivative Liabilities, Noncurrent		138	226
Commodity Contract | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		46	264
Derivative Asset, Noncurrent		30	4
Derivative Liabilities, Current		256	290
Derivative Liabilities, Noncurrent		52	58
Interest Rate Contract
Derivatives Fair Value [Line Items]
Derivative Asset, Current		63	605
Derivative Asset, Noncurrent		1,238	802
Derivative Liabilities, Current		65	70
Derivative Liabilities, Noncurrent		363	307
Interest Rate Contract | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0	501
Derivative Asset, Noncurrent		389	113
Derivative Liabilities, Current		0	0
Derivative Liabilities, Noncurrent		0	7
Foreign currency exchange rate
Derivatives Fair Value [Line Items]
Derivative Asset, Current		9
Derivative Liabilities, Current		54	8
Derivative Liabilities, Noncurrent		108	93
Foreign currency exchange rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		9
Derivative Liabilities, Current		54	8
Derivative Liabilities, Noncurrent		108	93
Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	0	501
Derivative Asset, Noncurrent		389	113
Derivatives Assets		389	614
Derivative Liabilities, Current	[2]	0	0
Derivative Liabilities, Noncurrent		0	7
Derivative Liabilities		0	7
Designated as Hedging Instrument | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	0	501
Derivative Asset, Noncurrent		389	113
Derivatives Assets		389	614
Derivative Liabilities, Current	[2]	0	0
Derivative Liabilities, Noncurrent		0	7
Derivative Liabilities		0	7
Designated as Hedging Instrument | Commodity Contract
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0	0
Derivative Asset, Noncurrent		0	0
Derivative Liabilities, Current		0	0
Derivative Liabilities, Noncurrent		0	0
Designated as Hedging Instrument | Commodity Contract | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0	0
Derivative Asset, Noncurrent		0	0
Derivative Liabilities, Current		0	0
Derivative Liabilities, Noncurrent		0	0
Designated as Hedging Instrument | Interest Rate Contract
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0	501
Derivative Asset, Noncurrent		389	113
Derivative Liabilities, Current		0	0
Derivative Liabilities, Noncurrent		0	7
Designated as Hedging Instrument | Interest Rate Contract | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0	501
Derivative Asset, Noncurrent		389	113
Derivative Liabilities, Current		0	0
Derivative Liabilities, Noncurrent		0	7
Designated as Hedging Instrument | Foreign currency exchange rate
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0
Derivative Liabilities, Current		0	0
Derivative Liabilities, Noncurrent		0	0
Designated as Hedging Instrument | Foreign currency exchange rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0
Derivative Liabilities, Current		0	0
Derivative Liabilities, Noncurrent		0	0
Fair Value - Derivatives not under Hedge Accounting
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	231	636
Derivative Asset, Noncurrent		1,026	926
Derivatives Assets		1,257	1,562
Derivative Liabilities, Current	[2]	469	778
Derivative Liabilities, Noncurrent		609	619
Derivative Liabilities		1,078	1,397
Fair Value - Derivatives not under Hedge Accounting | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	55	264
Derivative Asset, Noncurrent		30	4
Derivatives Assets		85	268
Derivative Liabilities, Current	[2]	310	298
Derivative Liabilities, Noncurrent		160	151
Derivative Liabilities		470	449
Fair Value - Derivatives not under Hedge Accounting | Commodity Contract
Derivatives Fair Value [Line Items]
Derivative Asset, Current		159	532
Derivative Asset, Noncurrent		177	237
Derivative Liabilities, Current		350	700
Derivative Liabilities, Noncurrent		138	226
Fair Value - Derivatives not under Hedge Accounting | Commodity Contract | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		46	264
Derivative Asset, Noncurrent		30	4
Derivative Liabilities, Current		256	290
Derivative Liabilities, Noncurrent		52	58
Fair Value - Derivatives not under Hedge Accounting | Interest Rate Contract
Derivatives Fair Value [Line Items]
Derivative Asset, Current		63	104
Derivative Asset, Noncurrent		849	689
Derivative Liabilities, Current		65	70
Derivative Liabilities, Noncurrent		363	300
Fair Value - Derivatives not under Hedge Accounting | Interest Rate Contract | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0	0
Derivative Asset, Noncurrent		0	0
Derivative Liabilities, Current		0	0
Derivative Liabilities, Noncurrent		0	0
Fair Value - Derivatives not under Hedge Accounting | Foreign currency exchange rate
Derivatives Fair Value [Line Items]
Derivative Asset, Current		9
Derivative Liabilities, Current		54	8
Derivative Liabilities, Noncurrent		108	93
Fair Value - Derivatives not under Hedge Accounting | Foreign currency exchange rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		9
Derivative Liabilities, Current		54	8
Derivative Liabilities, Noncurrent		$ 108	$ 93

[1] Includes $10 million and $118 million recorded in current assets held for sale in Dominion Energy's Consolidated Balance Sheets at September 30, 2023 and December 31, 2022, respectively.

[2] Includes $12 million and $6 million recorded in current liabilities held for sale in Dominion Energy's Consolidated Balance Sheets at September 30, 2023 and December 31, 2022, respectively.