Related Party Transactions (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Derivative assets		$ 279	$ 388
Derivative liabilities		155	343
Capital expenditures		6,085	5,575	$ 5,345
Virginia Electric and Power Company
Related Party Transaction [Line Items]
Derivative assets		194	127
Derivative liabilities		31	86
Commodity purchases from affiliates		571	555	543
Services provided by affiliates	[1]	454	422	432
Services provided to affiliates		22	22	22
Capital expenditures		2,489	2,474	2,911
Virginia Electric and Power Company | Noncurrent Pension and Other Postretirement Benefit Liabilities
Related Party Transaction [Line Items]
Amounts due to affiliate		396	316
Virginia Electric and Power Company | Noncurrent Pension and Other Postretirement Benefit Assets
Related Party Transaction [Line Items]
Amounts due from affiliate		130	77
Virginia Electric and Power Company | Affiliated Entity
Related Party Transaction [Line Items]
Derivative assets		41	13
Derivative liabilities		8	22
Virginia Electric and Power Company | Affiliated Entity | Services provided by affiliates
Related Party Transaction [Line Items]
Capital expenditures		144	143	146
Virginia Electric and Power Company | Dominion
Related Party Transaction [Line Items]
Short term demand note borrowings		$ 262	$ 376
Weighted- average interest rate percentage		0.97%	0.60%
Dominion Gas Holdings, LLC
Related Party Transaction [Line Items]
Derivative assets			$ 11
Derivative liabilities		$ 11	14
Amounts due from affiliate		1	4
Services provided by affiliates	[2]	128	101	17
Services provided to affiliates		69	69	84
Capital expenditures		854	795	719
Purchases of natural gas and transportation and storage services from affiliates		9	10	34
Customer receivables from related parties	[3]	10	7
Affiliated notes receivable	[4]	$ 18	$ 14
Dominion Gas Holdings, LLC | Revolving Credit Facility | IRCA
Related Party Transaction [Line Items]
Weighted- average interest rate percentage		1.08%	0.65%
Borrowings under IRCA		$ 118	$ 95
Interest charges				4
Dominion Gas Holdings, LLC | Services provided by affiliates
Related Party Transaction [Line Items]
Purchases of natural gas and transportation and storage services from affiliates	[5]	141	133	106
Dominion Gas Holdings, LLC | Noncurrent Pension and Other Postretirement Benefit Assets
Related Party Transaction [Line Items]
Amounts due from Dominion		697	652
Dominion Gas Holdings, LLC | Affiliated Entity
Related Party Transaction [Line Items]
Imbalances receivable from affiliates		2	1
Imbalances payable to affiliates	[6]	4	0
Dominion Gas Holdings, LLC | Affiliated Entity | Services provided by affiliates
Related Party Transaction [Line Items]
Capital expenditures		$ 49	$ 57	$ 49

[1] Includes capitalized expenditures of $144 million, $143 million and $146 million for the year ended December 31, 2016, 2015, and 2014, respectively.

[2] Amounts primarily attributable to Atlantic Coast Pipeline.

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

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

[5] Includes capitalized expenditures of $49 million, $57 million and $49 million for the year ended December 31, 2016, 2015, and 2014, respectively.

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