Derivatives and Hedge Accounting Activities (Fair Value of Derivatives) (Detail) - USD ($) $ in Millions		Jun. 30, 2021	Dec. 31, 2020
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	$ 100	$ 67
Derivative Asset, Noncurrent	[2]	516	330
Derivative Asset		616	397
Derivative Liabilities, Current	[3]	435	415
Derivative Liabilities, Noncurrent	[4]	139	71
Derivative Liabilities		574	486
Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[5]	52	22
Derivative Asset, Noncurrent	[6]	231	159
Derivative Asset		283	181
Derivative Liabilities, Current	[7]	296	390	[8]
Derivative Liabilities, Noncurrent	[9]	39	15
Derivative Liabilities		335	405
Commodity contracts
Derivatives Fair Value [Line Items]
Derivative Asset, Current		76	58
Derivative Asset, Noncurrent		72	109
Derivative Liabilities, Current		172	42
Derivative Liabilities, Noncurrent		73	13
Commodity contracts | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		52	22
Derivative Asset, Noncurrent		59	93
Derivative Liabilities, Current		43	28
Derivative Liabilities, Noncurrent		9	1
Interest rate contracts
Derivatives Fair Value [Line Items]
Derivative Asset, Current		24	9
Derivative Asset, Noncurrent		444	221
Derivative Liabilities, Current		263	373
Derivative Liabilities, Noncurrent		66	58
Interest rate contracts | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Noncurrent		172	66
Derivative Liabilities, Current		253	362
Derivative Liabilities, Noncurrent		30	14
Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	0	0
Derivative Asset, Noncurrent	[2]	172	66
Derivative Asset		172	66
Derivative Liabilities, Current	[3]	253	363
Derivative Liabilities, Noncurrent	[4]	31	19
Derivative Liabilities		284	382
Designated as Hedging Instrument | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[5]	0	0
Derivative Asset, Noncurrent	[6]	172	66
Derivative Asset		172	66
Derivative Liabilities, Current		253	362
Derivative Liabilities, Noncurrent	[9]	30	14
Derivative Liabilities		283	376
Designated as Hedging Instrument | Commodity contracts
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 contracts | 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 contracts
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0	0
Derivative Asset, Noncurrent		172	66
Derivative Liabilities, Current		253	363
Derivative Liabilities, Noncurrent		31	19
Designated as Hedging Instrument | Interest rate contracts | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Noncurrent		172	66
Derivative Liabilities, Current		253	362
Derivative Liabilities, Noncurrent		30	14
Fair Value - Derivatives not under Hedge Accounting
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	100	67
Derivative Asset, Noncurrent	[2]	344	264
Derivative Asset		444	331
Derivative Liabilities, Current	[3]	182	52
Derivative Liabilities, Noncurrent	[4]	108	52
Derivative Liabilities		290	104
Fair Value - Derivatives not under Hedge Accounting | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[5]	52	22
Derivative Asset, Noncurrent	[6]	59	93
Derivative Asset		111	115
Derivative Liabilities, Current		43	28
Derivative Liabilities, Noncurrent	[9]	9	1
Derivative Liabilities		52	29
Fair Value - Derivatives not under Hedge Accounting | Commodity contracts
Derivatives Fair Value [Line Items]
Derivative Asset, Current		76	58
Derivative Asset, Noncurrent		72	109
Derivative Liabilities, Current		172	42
Derivative Liabilities, Noncurrent		73	13
Fair Value - Derivatives not under Hedge Accounting | Commodity contracts | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		52	22
Derivative Asset, Noncurrent		59	93
Derivative Liabilities, Current		43	28
Derivative Liabilities, Noncurrent		9	1
Fair Value - Derivatives not under Hedge Accounting | Interest rate contracts
Derivatives Fair Value [Line Items]
Derivative Asset, Current		24	9
Derivative Asset, Noncurrent		272	155
Derivative Liabilities, Current		10	10
Derivative Liabilities, Noncurrent		35	39
Fair Value - Derivatives not under Hedge Accounting | Interest rate contracts | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Noncurrent		0	0
Derivative Liabilities, Current		0	0
Derivative Liabilities, Noncurrent		$ 0	$ 0

[1] Current derivative assets include $87 million and $63 million in other current assets in Dominion Energy’s Consolidated Balance Sheets as of June 30, 2021 and December 31, 2020, respectively.  The remainder is recorded in current assets held for sale in Dominion Energy’s Consolidated Balance Sheets.

[2] Noncurrent derivative assets are presented in other deferred charges and other assets in Dominion Energy’s Consolidated Balance Sheets.

[3] Current derivative liabilities include $428 million and $412 million in other current liabilities in Dominion Energy’s Consolidated Balance Sheets as of June 30, 2021 and December 31, 2020, respectively. The remainder is in current liabilities held for sale in Dominion Energy’s Consolidated Balance Sheets.

[4] Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in Dominion Energy’s Consolidated Balance Sheets.

[5] Current derivative assets are presented in other current assets in Virginia Power’s Consolidated Balance Sheets.

[6] Noncurrent derivative assets are presented in other deferred charges and other assets in Virginia Power’s Consolidated Balance Sheets.

[7] See Note 19 for amounts attributable to affiliates.

[8] Virginia Power’s Consolidated Balance Sheet at December 31, 2020 has been derived from the audited Consolidated Balance Sheet at that date.

[9] Noncurrent derivative liabilities are presented in other deferred credits and other liabilities in Virginia Power’s Consolidated Balance Sheets.