Derivatives and Hedge Accounting Activities (Fair Value of Derivatives) (Detail) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	$ 67	$ 68
Derivative Asset, Noncurrent	[2]	330	25
Derivative Asset		397	93
Derivative Liabilities, Current	[3]	415	408
Derivative Liabilities, Noncurrent	[4]	71	332
Derivative Liabilities		486	740
Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[5]	22	20
Derivative Asset, Noncurrent	[6]	159	4
Derivative Asset		181	24
Derivative liabilities	[7]	390	243
Derivative Liability, Noncurrent	[8]	15	223
Derivative Liabilities		405	466
Commodity
Derivatives Fair Value [Line Items]
Derivative Asset, Current		58	67
Derivative Asset, Noncurrent		109	7
Derivative Liabilities, Current		42	83
Derivative Liabilities, Noncurrent		13	48
Commodity | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		22	20
Derivative Asset, Noncurrent		93	2
Derivative liabilities		28	58
Derivative Liability, Noncurrent		1	45
Interest rate
Derivatives Fair Value [Line Items]
Derivative Asset, Current		9	1
Derivative Asset, Noncurrent		221	10
Derivative Liabilities, Current		373	322
Derivative Liabilities, Noncurrent		58	284
Interest rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current			0
Derivative Asset, Noncurrent		66	2
Derivative liabilities		362	185
Derivative Liability, Noncurrent		14	178
Foreign currency
Derivatives Fair Value [Line Items]
Derivative Asset, Noncurrent			8
Derivative Liabilities, Current			3
Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	0	31
Derivative Asset, Noncurrent	[2]	66	19
Derivative Asset		66	50
Derivative Liabilities, Current	[3]	363	330
Derivative Liabilities, Noncurrent	[4]	19	268
Derivative Liabilities		382	598
Designated as Hedging Instrument | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[5]	0	0
Derivative Asset, Noncurrent	[6]	66	2
Derivative Asset		66	2
Derivative liabilities		362	185
Derivative Liability, Noncurrent	[8]	14	178
Derivative Liabilities		376	363
Designated as Hedging Instrument | Commodity
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0	30
Derivative Asset, Noncurrent		0	1
Derivative Liabilities, Current		0	6
Derivative Liabilities, Noncurrent		0	1
Designated as Hedging Instrument | Commodity | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0	0
Derivative Asset, Noncurrent		0	0
Derivative liabilities		0	0
Derivative Liability, Noncurrent		0	0
Designated as Hedging Instrument | Interest rate
Derivatives Fair Value [Line Items]
Derivative Asset, Current		0	1
Derivative Asset, Noncurrent		66	10
Derivative Liabilities, Current		363	321
Derivative Liabilities, Noncurrent		19	267
Designated as Hedging Instrument | Interest rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current			0
Derivative Asset, Noncurrent		66	2
Derivative liabilities		362	185
Derivative Liability, Noncurrent		14	178
Designated as Hedging Instrument | Foreign currency
Derivatives Fair Value [Line Items]
Derivative Asset, Noncurrent			8
Derivative Liabilities, Current			3
Fair Value - Derivatives not under Hedge Accounting
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[1]	67	37
Derivative Asset, Noncurrent	[2]	264	6
Derivative Asset		331	43
Derivative Liabilities, Current	[3]	52	78
Derivative Liabilities, Noncurrent	[4]	52	64
Derivative Liabilities		104	142
Fair Value - Derivatives not under Hedge Accounting | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current	[5]	22	20
Derivative Asset, Noncurrent	[6]	93	2
Derivative Asset		115	22
Derivative liabilities		28	58
Derivative Liability, Noncurrent	[8]	1	45
Derivative Liabilities		29	103
Fair Value - Derivatives not under Hedge Accounting | Commodity
Derivatives Fair Value [Line Items]
Derivative Asset, Current		58	37
Derivative Asset, Noncurrent		109	6
Derivative Liabilities, Current		42	77
Derivative Liabilities, Noncurrent		13	47
Fair Value - Derivatives not under Hedge Accounting | Commodity | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current		22	20
Derivative Asset, Noncurrent		93	2
Derivative liabilities		28	58
Derivative Liability, Noncurrent		1	45
Fair Value - Derivatives not under Hedge Accounting | Interest rate
Derivatives Fair Value [Line Items]
Derivative Asset, Current		9	0
Derivative Asset, Noncurrent		155	0
Derivative Liabilities, Current		10	1
Derivative Liabilities, Noncurrent		39	17
Fair Value - Derivatives not under Hedge Accounting | Interest rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset, Current			0
Derivative Asset, Noncurrent		0	0
Derivative liabilities		0	0
Derivative Liability, Noncurrent		$ 0	0
Fair Value - Derivatives not under Hedge Accounting | Foreign currency
Derivatives Fair Value [Line Items]
Derivative Asset, Noncurrent			0
Derivative Liabilities, Current			$ 0

[1] Current derivative assets include $63 million and $61 million in other current assets in Dominion Energy’s Consolidated Balance Sheets as of December 31, 2020 and 2019, respectively. The remainder is recorded in current assets held for sale in Dominion Energy’s Consolidated Balance Sheets.

[2] Noncurrent derivative assets include $330 million and $16 million in other deferred charges and other assets in Dominion Energy’s Consolidated Balance Sheets as of December 31, 2020 and 2019, respectively. The remainder is recorded in noncurrent assets held for sale in Dominion Energy’s Consolidated Balance Sheets.

[3] Current derivative liabilities include $412 million and $394 million in other current liabilities in Dominion Energy’s Consolidated Balance Sheets as of December 31, 2020 and 2019, respectively. The remainder is recorded in current liabilities held for sale in Dominion Energy’s Consolidated Balance Sheets.

[4] Noncurrent derivative liabilities include $71 million and $329 million in other deferred credits and other liabilities in Dominion Energy’s Consolidated Balance Sheets as of December 31, 2020 and 2019, respectively. The remainder is recorded in noncurrent liabilities held for sale 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 25 for amounts attributable to affiliates.

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