Related-Party Transactions (Details) - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Related Party Transaction [Line Items]
Derivative Asset		$ 354,000,000		$ 354,000,000		$ 388,000,000
Derivative Liabilities		473,000,000		473,000,000		343,000,000
Capital expenditures				3,160,000,000	$ 2,370,000,000
Virginia Electric and Power Company
Related Party Transaction [Line Items]
Derivative Asset		163,000,000		163,000,000		127,000,000
Derivative Liabilities		274,000,000		274,000,000		86,000,000
Commodity purchases from affiliates		99,000,000	$ 94,000,000	244,000,000	346,000,000
Services provided by affiliates	[1]	102,000,000	107,000,000	242,000,000	217,000,000
Services provided to affiliates		7,000,000	5,000,000	12,000,000	10,000,000
Capital expenditures				1,226,000,000	1,292,000,000
Outstanding borrowings, net of repayments, under money pool for non-regulated subsidiaries		0		0		0
Virginia Electric and Power Company | Affiliate
Related Party Transaction [Line Items]
Derivative Asset		36,000,000		36,000,000		13,000,000
Derivative Liabilities		3,000,000		3,000,000		22,000,000
Virginia Electric and Power Company | Affiliate | Services provided by affiliates
Related Party Transaction [Line Items]
Capital expenditures		38,000,000	38,000,000	77,000,000	73,000,000
Virginia Electric and Power Company | Principal Owner
Related Party Transaction [Line Items]
Short term demand note		0		0		376,000,000
Virginia Electric and Power Company | Other deferred credits and other liabilities
Related Party Transaction [Line Items]
Amounts due to Dominion		356,000,000		356,000,000		316,000,000
Virginia Electric and Power Company | Other deferred charges and other assets
Related Party Transaction [Line Items]
Amounts due from Dominion		98,000,000		98,000,000		77,000,000
Dominion Gas Holdings, LLC
Related Party Transaction [Line Items]
Derivative Asset		3,000,000		3,000,000		11,000,000
Derivative Liabilities		12,000,000		12,000,000		14,000,000
Amounts due from Dominion	[2]	3,000,000		3,000,000		1,000,000
Commodity purchases from affiliates		2,000,000	2,000,000	5,000,000	4,000,000
Services provided by affiliates	[3]	33,000,000	25,000,000	60,000,000	45,000,000
Services provided to affiliates		18,000,000	17,000,000	35,000,000	35,000,000
Capital expenditures				393,000,000	292,000,000
Other receivables	[4]	8,000,000		8,000,000		7,000,000
Customer receivables from related parties		10,000,000		10,000,000		4,000,000
Affiliated notes receivable	[5]	16,000,000		16,000,000		14,000,000
Dominion Gas Holdings, LLC | Revolving Credit Facility | IRCA
Related Party Transaction [Line Items]
Borrowings under IRCA						95,000,000
Dominion Gas Holdings, LLC | Services provided by affiliates
Related Party Transaction [Line Items]
Commodity purchases from affiliates	[6]	33,000,000	34,000,000	72,000,000	68,000,000
Dominion Gas Holdings, LLC | Affiliate | Services provided by affiliates
Related Party Transaction [Line Items]
Capital expenditures		14,000,000	$ 15,000,000	24,000,000	$ 24,000,000
Dominion Gas Holdings, LLC | Noncurrent Pension and Other Postretirement Benefit Assets
Related Party Transaction [Line Items]
Amounts due from Dominion, noncurrent		$ 674,000,000		$ 674,000,000		$ 652,000,000

[1] Includes capitalized expenditures of $38 million for both the three months ended June 30, 2016 and 2015, respectively, and $77 million and $73 million for the six months ended June 30, 2016 and 2015, respectively.

[2] Amounts are presented in other current assets in Dominion Gas' Consolidated Balance Sheets.

[3] Amounts primarily attributable to Atlantic Coast Pipeline.

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

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

[6] Includes capitalized expenditures of $14 million and $15 million for the three months ended June 30, 2016 and 2015, respectively, and $24 million for both the six months ended June 30, 2016 and 2015