Asset Retirement Obligations (Changes to AROs) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
AROs, Beginning balance		$ 2,103	[1]	$ 1,714
Obligations incurred during the period		204	[2]	315	[3]
Obligations settled during the period		(171)		(106)
Revisions in estimated cash flows	[3]	245		88
Accretion		104		93
Other				(1)
AROs , Ending balance	[1]	2,485		2,103
Asset retirement obligations, non current		2,236		1,887
Current Liabilities
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligation, current		249		216
Virginia Electric and Power Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
AROs, Beginning balance		1,247		855
Obligations incurred during the period		9		289	[3]
Obligations settled during the period		(115)		(39)
Revisions in estimated cash flows	[3]	245		92
Accretion		57		50
AROs , Ending balance		1,443		1,247
Asset retirement obligation, current		181		143
Asset retirement obligations, non current		1,262		1,104
Dominion Gas Holdings, LLC
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
AROs, Beginning balance		149	[4]	147
Obligations incurred during the period		6		5
Obligations settled during the period		(8)		(6)
Revisions in estimated cash flows		0		(5)
Accretion		9		9
Other				(1)
AROs , Ending balance	[4]	156		149
Dominion Gas Holdings, LLC | Other Deferred Credits and Other Liabilities
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations, non current		$ 147		$ 137

[1] Includes $216 million and $249 million reported in other current liabilities at December 31, 2015, and 2016, respectively.

[2] Primarily reflects AROs assumed in the Dominion Questar Combination. See Note 3 for further information.

[3] Primarily reflects future ash pond and landfill closure costs at certain utility generation facilities. See Note 22 for further information.

[4] Includes $137 million and $147 million reported in other deferred credits and other liabilities, with the remainder recorded in other current liabilities, at December 31, 2015 and 2016, respectively.