Related-Party Transactions (Details) - USD ($)		3 Months Ended			6 Months Ended
		Jun. 30, 2017		Jun. 30, 2016	Jun. 30, 2017		Jun. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Derivative Asset		$ 281,000,000	[1]		$ 281,000,000	[1]		$ 279,000,000	[2]
Derivative Liabilities		150,000,000	[3]		150,000,000	[3]		155,000,000	[4]
Capital expenditures					2,748,000,000		$ 3,150,000,000
Virginia Electric and Power Company
Related Party Transaction [Line Items]
Derivative Asset	[2]	167,000,000			167,000,000			194,000,000
Derivative Liabilities	[4]	74,000,000			74,000,000			31,000,000
Commodity purchases from affiliates		137,000,000		$ 99,000,000	349,000,000		244,000,000
Services provided by affiliates	[5]	112,000,000		102,000,000	224,000,000		242,000,000
Services provided to affiliates		7,000,000		$ 7,000,000	12,000,000		12,000,000
Capital expenditures					1,219,000,000		$ 1,226,000,000
Short term demand note		12,000,000			12,000,000			262,000,000	[6]
Outstanding borrowings, net of repayments, under money pool for non-regulated subsidiaries		$ 0			$ 0			0
Issuance of common stock (in shares)		0		0	0		0
Virginia Electric and Power Company | Pension Benefits | Amounts Associated with the Dominion Pension Plan
Related Party Transaction [Line Items]
Amounts due to Dominion		$ 451,000,000			$ 451,000,000			396,000,000
Virginia Electric and Power Company | Dominion Retiree Health and Welfare plan | Amounts Associated with the Dominion Retiree Health and Welfare Plan
Related Party Transaction [Line Items]
Amounts due to Dominion		165,000,000			165,000,000			130,000,000
Virginia Electric and Power Company | Affiliate
Related Party Transaction [Line Items]
Derivative Asset		13,000,000			13,000,000			41,000,000
Derivative Liabilities		10,000,000			10,000,000			8,000,000
Virginia Electric and Power Company | Affiliate | Services provided by affiliates
Related Party Transaction [Line Items]
Capital expenditures		37,000,000		$ 38,000,000	71,000,000		$ 77,000,000
Virginia Electric and Power Company | Principal Owner
Related Party Transaction [Line Items]
Short term demand note		12,000,000			12,000,000			262,000,000
Dominion Energy Gas Holdings, LLC
Related Party Transaction [Line Items]
Derivative Asset		17,000,000			17,000,000
Derivative Liabilities		5,000,000			5,000,000			11,000,000
Commodity purchases from affiliates		2,000,000		2,000,000	2,000,000		5,000,000
Services provided by affiliates	[7]	36,000,000		33,000,000	75,000,000		60,000,000
Services provided to affiliates		18,000,000		18,000,000	36,000,000		35,000,000
Capital expenditures					309,000,000		393,000,000
Short term demand note		24,000,000			24,000,000			118,000,000	[8]
Other receivables	[9]	15,000,000			15,000,000			10,000,000
Affiliated notes receivable	[10]	20,000,000			20,000,000			18,000,000
Dominion Energy Gas Holdings, LLC | Revolving Credit Facility | IRCA
Related Party Transaction [Line Items]
Short term demand note		24,000,000			24,000,000			118,000,000
Dominion Energy Gas Holdings, LLC | Services provided by affiliates
Related Party Transaction [Line Items]
Commodity purchases from affiliates	[11]	35,000,000		33,000,000	70,000,000		72,000,000
Dominion Energy Gas Holdings, LLC | Pension Benefits | Amounts Associated with the Dominion Pension Plan
Related Party Transaction [Line Items]
Amounts due from Dominion, noncurrent		716,000,000			716,000,000			697,000,000
Dominion Energy Gas Holdings, LLC | Dominion Retiree Health and Welfare plan | Amounts Associated with the Dominion Retiree Health and Welfare Plan
Related Party Transaction [Line Items]
Amounts due from Dominion, noncurrent		4,000,000			4,000,000			2,000,000
Dominion Energy Gas Holdings, LLC | Affiliate
Related Party Transaction [Line Items]
Imbalances receivable from affiliates		1,000,000			1,000,000			2,000,000
Imbalances payable to affiliates	[12]	1,000,000			1,000,000			$ 4,000,000
Dominion Energy Gas Holdings, LLC | Affiliate | Services provided by affiliates
Related Party Transaction [Line Items]
Capital expenditures		$ 12,000,000		$ 14,000,000	$ 20,000,000		$ 24,000,000

[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] Includes capitalized expenditures of $37 million and $38 million for the three months ended June 30, 2017 and 2016, respectively, and $71 million and $77 million for the six months ended June 30, 2017 and 2016, respectively.

[6] Virginia Power’s Consolidated Balance Sheet at December 31, 2016 has been derived from the audited Consolidated Balance Sheet at that date.

[7] Amounts primarily attributable to Atlantic Coast Pipeline, a related-party VIE.

[8] Dominion Energy Gas’ Consolidated Balance Sheet at December 31, 2016 has been derived from the audited Consolidated Balance Sheet at that date.

[9] Represents amounts due from Atlantic Coast Pipeline, a related-party VIE.

[10] Amounts are presented in other deferred charges and other assets in Dominion Energy Gas' Consolidated Balance Sheets.

[11] Includes capitalized expenditures of $12 million and $14 million for the three months ended June 30, 2017 and 2016, respectively, and $20 million and $24 million for the six months ended June 30, 2017 and 2016, respectively.

[12] Amounts are presented in other current liabilities in Dominion Energy Gas' Consolidated Balance Sheets.