Derivatives and Hedge Accounting Activities (Fair Value of Derivatives) (Details) - USD ($) $ in Millions		Sep. 30, 2017		Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Asset		$ 249	[1]	$ 279	[2]
Derivative Liabilities		118	[3]	155	[4]
Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset	[2]	168		194
Derivative Liabilities	[4]	61		31
Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset		26
Derivative Liabilities		10		11
Current Assets
Derivatives, Fair Value [Line Items]
Derivative Asset		111	[5]	140	[6]
Current Assets | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset	[6]	61		66
Current Assets | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset	[7]	1
Current Assets | Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset		102		130
Current Assets | Commodity | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset		61		60
Current Assets | Commodity | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset		1
Current Assets | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Asset		9		10
Current Assets | Interest rate | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset				6
Noncurrent Assets
Derivatives, Fair Value [Line Items]
Derivative Asset		138		139
Noncurrent Assets | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset		107		128
Noncurrent Assets | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset	[8]	25
Noncurrent Assets | Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset		111		132
Noncurrent Assets | Commodity | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset		107		128
Noncurrent Assets | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Asset		2		7
Noncurrent Assets | Foreign currency
Derivatives, Fair Value [Line Items]
Derivative Asset		25
Noncurrent Assets | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset		25
Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities		65	[9]	128	[10]
Current Liabilities | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities	[10]	23		18
Current Liabilities | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities	[7]	10		7
Current Liabilities | Commodity
Derivatives, Fair Value [Line Items]
Derivative Liabilities		40		92
Current Liabilities | Commodity | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		6		10
Current Liabilities | Commodity | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities		6		4
Current Liabilities | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Liabilities		21		33
Current Liabilities | Interest rate | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		17		8
Current Liabilities | Foreign currency
Derivatives, Fair Value [Line Items]
Derivative Liabilities		4		3
Current Liabilities | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities		4		3
Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities		53		27
Noncurrent Liabilities | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		38		13
Noncurrent Liabilities | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities	[8]			4
Noncurrent Liabilities | Commodity
Derivatives, Fair Value [Line Items]
Derivative Liabilities		2		4
Noncurrent Liabilities | Commodity | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities				1
Noncurrent Liabilities | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Liabilities		51		20
Noncurrent Liabilities | Interest rate | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		38		13
Noncurrent Liabilities | Foreign currency
Derivatives, Fair Value [Line Items]
Derivative Liabilities				3
Noncurrent Liabilities | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities				3
Fair Value – Derivatives under Hedge Accounting
Derivatives, Fair Value [Line Items]
Derivative Asset		56	[1]	46	[2]
Derivative Liabilities		91	[3]	111	[4]
Fair Value – Derivatives under Hedge Accounting | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset	[2]	0		6
Derivative Liabilities	[4]	55		21
Fair Value – Derivatives under Hedge Accounting | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset		25
Derivative Liabilities		10		11
Fair Value – Derivatives under Hedge Accounting | Current Assets
Derivatives, Fair Value [Line Items]
Derivative Asset		28	[5]	39	[6]
Fair Value – Derivatives under Hedge Accounting | Current Assets | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset	[6]	0		6
Fair Value – Derivatives under Hedge Accounting | Current Assets | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset	[7]	0
Fair Value – Derivatives under Hedge Accounting | Current Assets | Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset		19		29
Fair Value – Derivatives under Hedge Accounting | Current Assets | Commodity | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset		0		0
Fair Value – Derivatives under Hedge Accounting | Current Assets | Commodity | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset		0
Fair Value – Derivatives under Hedge Accounting | Current Assets | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Asset		9		10
Fair Value – Derivatives under Hedge Accounting | Current Assets | Interest rate | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset				6
Fair Value – Derivatives under Hedge Accounting | Noncurrent Assets
Derivatives, Fair Value [Line Items]
Derivative Asset		28		7
Fair Value – Derivatives under Hedge Accounting | Noncurrent Assets | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset		0		0
Fair Value – Derivatives under Hedge Accounting | Noncurrent Assets | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset	[8]	25
Fair Value – Derivatives under Hedge Accounting | Noncurrent Assets | Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset		1		0
Fair Value – Derivatives under Hedge Accounting | Noncurrent Assets | Commodity | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset		0		0
Fair Value – Derivatives under Hedge Accounting | Noncurrent Assets | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Asset		2		7
Fair Value – Derivatives under Hedge Accounting | Noncurrent Assets | Foreign currency
Derivatives, Fair Value [Line Items]
Derivative Asset		25
Fair Value – Derivatives under Hedge Accounting | Noncurrent Assets | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset		25
Fair Value – Derivatives under Hedge Accounting | Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities		40	[9]	87	[10]
Fair Value – Derivatives under Hedge Accounting | Current Liabilities | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities	[10]	17		8
Fair Value – Derivatives under Hedge Accounting | Current Liabilities | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities	[7]	10		7
Fair Value – Derivatives under Hedge Accounting | Current Liabilities | Commodity
Derivatives, Fair Value [Line Items]
Derivative Liabilities		15		51
Fair Value – Derivatives under Hedge Accounting | Current Liabilities | Commodity | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		0		0
Fair Value – Derivatives under Hedge Accounting | Current Liabilities | Commodity | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities		6		4
Fair Value – Derivatives under Hedge Accounting | Current Liabilities | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Liabilities		21		33
Fair Value – Derivatives under Hedge Accounting | Current Liabilities | Interest rate | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		17		8
Fair Value – Derivatives under Hedge Accounting | Current Liabilities | Foreign currency
Derivatives, Fair Value [Line Items]
Derivative Liabilities		4		3
Fair Value – Derivatives under Hedge Accounting | Current Liabilities | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities		4		3
Fair Value – Derivatives under Hedge Accounting | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities		51		24
Fair Value – Derivatives under Hedge Accounting | Noncurrent Liabilities | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		38		13
Fair Value – Derivatives under Hedge Accounting | Noncurrent Liabilities | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities	[8]			4
Fair Value – Derivatives under Hedge Accounting | Noncurrent Liabilities | Commodity
Derivatives, Fair Value [Line Items]
Derivative Liabilities		0		1
Fair Value – Derivatives under Hedge Accounting | Noncurrent Liabilities | Commodity | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities				1
Fair Value – Derivatives under Hedge Accounting | Noncurrent Liabilities | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Liabilities		51		20
Fair Value – Derivatives under Hedge Accounting | Noncurrent Liabilities | Interest rate | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		38		13
Fair Value – Derivatives under Hedge Accounting | Noncurrent Liabilities | Foreign currency
Derivatives, Fair Value [Line Items]
Derivative Liabilities				3
Fair Value – Derivatives under Hedge Accounting | Noncurrent Liabilities | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities				3
Fair Value – Derivatives not under Hedge Accounting
Derivatives, Fair Value [Line Items]
Derivative Asset		193	[1]	233	[2]
Derivative Liabilities		27	[3]	44	[4]
Fair Value – Derivatives not under Hedge Accounting | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset	[2]	168		188
Derivative Liabilities	[4]	6		10
Fair Value – Derivatives not under Hedge Accounting | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset		1
Derivative Liabilities		0		0
Fair Value – Derivatives not under Hedge Accounting | Current Assets
Derivatives, Fair Value [Line Items]
Derivative Asset		83	[5]	101	[6]
Fair Value – Derivatives not under Hedge Accounting | Current Assets | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset	[6]	61		60
Fair Value – Derivatives not under Hedge Accounting | Current Assets | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset	[7]	1
Fair Value – Derivatives not under Hedge Accounting | Current Assets | Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset		83		101
Fair Value – Derivatives not under Hedge Accounting | Current Assets | Commodity | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset		61		60
Fair Value – Derivatives not under Hedge Accounting | Current Assets | Commodity | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset		1
Fair Value – Derivatives not under Hedge Accounting | Current Assets | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Asset		0		0
Fair Value – Derivatives not under Hedge Accounting | Current Assets | Interest rate | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset				0
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Assets
Derivatives, Fair Value [Line Items]
Derivative Asset		110		132
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Assets | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset		107		128
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Assets | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset	[8]	0
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Assets | Commodity
Derivatives, Fair Value [Line Items]
Derivative Asset		110		132
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Assets | Commodity | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Asset		107		128
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Assets | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Asset		0		0
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Assets | Foreign currency
Derivatives, Fair Value [Line Items]
Derivative Asset		0
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Assets | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Asset		0
Fair Value – Derivatives not under Hedge Accounting | Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities		25	[9]	41	[10]
Fair Value – Derivatives not under Hedge Accounting | Current Liabilities | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities	[10]	6		10
Fair Value – Derivatives not under Hedge Accounting | Current Liabilities | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities	[7]	0		0
Fair Value – Derivatives not under Hedge Accounting | Current Liabilities | Commodity
Derivatives, Fair Value [Line Items]
Derivative Liabilities		25		41
Fair Value – Derivatives not under Hedge Accounting | Current Liabilities | Commodity | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		6		10
Fair Value – Derivatives not under Hedge Accounting | Current Liabilities | Commodity | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities		0		0
Fair Value – Derivatives not under Hedge Accounting | Current Liabilities | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Liabilities		0		0
Fair Value – Derivatives not under Hedge Accounting | Current Liabilities | Interest rate | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		0		0
Fair Value – Derivatives not under Hedge Accounting | Current Liabilities | Foreign currency
Derivatives, Fair Value [Line Items]
Derivative Liabilities		0		0
Fair Value – Derivatives not under Hedge Accounting | Current Liabilities | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities		0		0
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities		2		3
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Liabilities | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		0		0
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Liabilities | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities	[8]			0
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Liabilities | Commodity
Derivatives, Fair Value [Line Items]
Derivative Liabilities		2		3
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Liabilities | Commodity | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities				0
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Liabilities | Interest rate
Derivatives, Fair Value [Line Items]
Derivative Liabilities		0		0
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Liabilities | Interest rate | Virginia Electric and Power Company
Derivatives, Fair Value [Line Items]
Derivative Liabilities		$ 0		0
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Liabilities | Foreign currency
Derivatives, Fair Value [Line Items]
Derivative Liabilities				0
Fair Value – Derivatives not under Hedge Accounting | Noncurrent Liabilities | Foreign currency | Dominion Energy Gas Holdings, LLC
Derivatives, Fair Value [Line Items]
Derivative Liabilities				$ 0

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

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

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

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

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

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

[7] Current derivative assets are presented in other current assets in Dominion Energy Gas’ Consolidated Balance Sheets. Noncurrent derivatives assets are presented in other deferred charges and other assets in Dominion Energy Gas’ Consolidated Balance Sheets. Current derivative liabilities are presented in other current liabilities in Dominion Energy Gas' Consolidated Balance Sheets.

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

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

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