Derivatives and Hedge Accounting Activities (Fair Value of Derivatives) (Detail) - USD ($) $ in Millions		Jun. 30, 2019	Dec. 31, 2018
Derivatives Fair Value [Line Items]
Derivative Asset		$ 209	$ 294
Derivative Liabilities		626	279
Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset		83	93
Derivative Liabilities		358	103
Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Asset		16	29
Derivative Liabilities		77	19
Current Assets
Derivatives Fair Value [Line Items]
Derivative Asset	[1]	113	223
Current Assets | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset	[2]	24	63
Current Assets | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Asset	[3]	2	3
Current Assets | Commodity
Derivatives Fair Value [Line Items]
Derivative Asset		113	209
Current Assets | Commodity | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset		24	60
Current Assets | Commodity | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Asset		2	3
Current Assets | Interest rate
Derivatives Fair Value [Line Items]
Derivative Asset			14
Current Assets | Interest rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset			3
Noncurrent Assets
Derivatives Fair Value [Line Items]
Derivative Asset	[4]	96	71
Noncurrent Assets | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset	[5]	59	30
Noncurrent Assets | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Asset	[6]	14	26
Noncurrent Assets | Commodity
Derivatives Fair Value [Line Items]
Derivative Asset		75	41
Noncurrent Assets | Commodity | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset		59	30
Noncurrent Assets | Interest rate
Derivatives Fair Value [Line Items]
Derivative Asset		7	4
Noncurrent Assets | Foreign currency
Derivatives Fair Value [Line Items]
Derivative Asset		14	26
Noncurrent Assets | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Asset		14	26
Current Liabilities
Derivatives Fair Value [Line Items]
Derivative Liabilities	[7]	201	157
Current Liabilities | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities	[8]	124	25
Current Liabilities | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Liabilities	[9]	34	11
Current Liabilities | Commodity
Derivatives Fair Value [Line Items]
Derivative Liabilities		58	129
Current Liabilities | Commodity | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities		20	15
Current Liabilities | Interest rate
Derivatives Fair Value [Line Items]
Derivative Liabilities		143	26
Current Liabilities | Interest rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities		104	10
Current Liabilities | Interest rate | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Liabilities		34	9
Current Liabilities | Foreign currency
Derivatives Fair Value [Line Items]
Derivative Liabilities			2
Current Liabilities | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Liabilities			2
Noncurrent Liabilities
Derivatives Fair Value [Line Items]
Derivative Liabilities	[10]	425	122
Noncurrent Liabilities | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities	[11]	234	78
Noncurrent Liabilities | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Liabilities	[12]	43	8
Noncurrent Liabilities | Commodity
Derivatives Fair Value [Line Items]
Derivative Liabilities		11	6
Noncurrent Liabilities | Commodity | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities		6
Noncurrent Liabilities | Interest rate
Derivatives Fair Value [Line Items]
Derivative Liabilities		414	116
Noncurrent Liabilities | Interest rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities		228	78
Noncurrent Liabilities | Interest rate | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Liabilities		43	8
Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Derivative Asset		74	105
Derivative Liabilities		551	166
Designated as Hedging Instrument | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset			3
Derivative Liabilities		332	88
Designated as Hedging Instrument | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Asset		16	29
Derivative Liabilities		77	19
Designated as Hedging Instrument | Current Assets
Derivatives Fair Value [Line Items]
Derivative Asset	[1]	43	69
Designated as Hedging Instrument | Current Assets | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset	[2]		3
Designated as Hedging Instrument | Current Assets | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Asset	[3]	2	3
Designated as Hedging Instrument | Current Assets | Commodity
Derivatives Fair Value [Line Items]
Derivative Asset		43	55
Designated as Hedging Instrument | Current Assets | Commodity | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Asset		2	3
Designated as Hedging Instrument | Current Assets | Interest rate
Derivatives Fair Value [Line Items]
Derivative Asset			14
Designated as Hedging Instrument | Current Assets | Interest rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset			3
Designated as Hedging Instrument | Noncurrent Assets
Derivatives Fair Value [Line Items]
Derivative Asset	[4]	31	36
Designated as Hedging Instrument | Noncurrent Assets | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Asset	[6]	14	26
Designated as Hedging Instrument | Noncurrent Assets | Commodity
Derivatives Fair Value [Line Items]
Derivative Asset		10	6
Designated as Hedging Instrument | Noncurrent Assets | Interest rate
Derivatives Fair Value [Line Items]
Derivative Asset		7	4
Designated as Hedging Instrument | Noncurrent Assets | Foreign currency
Derivatives Fair Value [Line Items]
Derivative Asset		14	26
Designated as Hedging Instrument | Noncurrent Assets | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Asset		14	26
Designated as Hedging Instrument | Current Liabilities
Derivatives Fair Value [Line Items]
Derivative Liabilities	[7]	152	45
Designated as Hedging Instrument | Current Liabilities | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities	[8]	104	10
Designated as Hedging Instrument | Current Liabilities | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Liabilities	[9]	34	11
Designated as Hedging Instrument | Current Liabilities | Commodity
Derivatives Fair Value [Line Items]
Derivative Liabilities		10	17
Designated as Hedging Instrument | Current Liabilities | Interest rate
Derivatives Fair Value [Line Items]
Derivative Liabilities		142	26
Designated as Hedging Instrument | Current Liabilities | Interest rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities		104	10
Designated as Hedging Instrument | Current Liabilities | Interest rate | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Liabilities		34	9
Designated as Hedging Instrument | Current Liabilities | Foreign currency
Derivatives Fair Value [Line Items]
Derivative Liabilities			2
Designated as Hedging Instrument | Current Liabilities | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Liabilities			2
Designated as Hedging Instrument | Noncurrent Liabilities
Derivatives Fair Value [Line Items]
Derivative Liabilities	[10]	399	121
Designated as Hedging Instrument | Noncurrent Liabilities | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities	[11]	228	78
Designated as Hedging Instrument | Noncurrent Liabilities | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Liabilities	[12]	43	8
Designated as Hedging Instrument | Noncurrent Liabilities | Commodity
Derivatives Fair Value [Line Items]
Derivative Liabilities		2	5
Designated as Hedging Instrument | Noncurrent Liabilities | Interest rate
Derivatives Fair Value [Line Items]
Derivative Liabilities		397	116
Designated as Hedging Instrument | Noncurrent Liabilities | Interest rate | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities		228	78
Designated as Hedging Instrument | Noncurrent Liabilities | Interest rate | Dominion Energy Gas Holdings, LLC
Derivatives Fair Value [Line Items]
Derivative Liabilities		43	8
Fair Value - Derivatives not under Hedge Accounting
Derivatives Fair Value [Line Items]
Derivative Asset		135	189
Derivative Liabilities		75	113
Fair Value - Derivatives not under Hedge Accounting | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset		83	90
Derivative Liabilities		26	15
Fair Value - Derivatives not under Hedge Accounting | Current Assets
Derivatives Fair Value [Line Items]
Derivative Asset	[1]	70	154
Fair Value - Derivatives not under Hedge Accounting | Current Assets | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset	[2]	24	60
Fair Value - Derivatives not under Hedge Accounting | Current Assets | Commodity
Derivatives Fair Value [Line Items]
Derivative Asset		70	154
Fair Value - Derivatives not under Hedge Accounting | Current Assets | Commodity | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset		24	60
Fair Value - Derivatives not under Hedge Accounting | Noncurrent Assets
Derivatives Fair Value [Line Items]
Derivative Asset	[4]	65	35
Fair Value - Derivatives not under Hedge Accounting | Noncurrent Assets | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset	[5]	59	30
Fair Value - Derivatives not under Hedge Accounting | Noncurrent Assets | Commodity
Derivatives Fair Value [Line Items]
Derivative Asset		65	35
Fair Value - Derivatives not under Hedge Accounting | Noncurrent Assets | Commodity | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Asset		59	30
Fair Value - Derivatives not under Hedge Accounting | Current Liabilities
Derivatives Fair Value [Line Items]
Derivative Liabilities	[7]	49	112
Fair Value - Derivatives not under Hedge Accounting | Current Liabilities | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities	[8]	20	15
Fair Value - Derivatives not under Hedge Accounting | Current Liabilities | Commodity
Derivatives Fair Value [Line Items]
Derivative Liabilities		48	112
Fair Value - Derivatives not under Hedge Accounting | Current Liabilities | Commodity | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities		20	15
Fair Value - Derivatives not under Hedge Accounting | Current Liabilities | Interest rate
Derivatives Fair Value [Line Items]
Derivative Liabilities		1
Fair Value - Derivatives not under Hedge Accounting | Noncurrent Liabilities
Derivatives Fair Value [Line Items]
Derivative Liabilities	[10]	26	1
Fair Value - Derivatives not under Hedge Accounting | Noncurrent Liabilities | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities	[11]	6
Fair Value - Derivatives not under Hedge Accounting | Noncurrent Liabilities | Commodity
Derivatives Fair Value [Line Items]
Derivative Liabilities		9	$ 1
Fair Value - Derivatives not under Hedge Accounting | Noncurrent Liabilities | Commodity | Virginia Electric and Power Company
Derivatives Fair Value [Line Items]
Derivative Liabilities		6
Fair Value - Derivatives not under Hedge Accounting | Noncurrent Liabilities | Interest rate
Derivatives Fair Value [Line Items]
Derivative Liabilities		$ 17

[1] Current derivative assets are presented in other current assets in Dominion Energy’s Consolidated Balance Sheets.

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

[3] Current derivative assets are presented in other current assets in Dominion Energy Gas’ Consolidated Balance Sheets.

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

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

[6] Noncurrent derivatives assets are presented in other deferred charges and other assets in Dominion Energy Gas’ Consolidated Balance Sheets.

[7] Current derivative liabilities are presented in other current liabilities in Dominion Energy’s Consolidated Balance Sheets.

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

[9] Current derivative liabilities are presented in other current liabilities in Dominion Energy Gas’ Consolidated Balance Sheets.

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

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

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