Investments (Recorded Other-Than-Temporary Impairment Losses on Investments) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Total other-than-temporary impairment losses	[1]	$ 51	$ 66	$ 21
Losses recorded to nuclear decommissioning trust regulatory liability		(16)	(26)	(5)
Losses recognized in other comprehensive income (before taxes)		(12)	(9)	(3)
Net impairment losses recognized in earnings		23	31	13
Other-than-temporary impairment losses for debt securities		13	9	3
Virginia Electric and Power Company
Schedule of Available-for-sale Securities [Line Items]
Total other-than-temporary impairment losses	[2]	26	36	8
Losses recorded to nuclear decommissioning trust regulatory liability		(16)	(26)	(4)
Losses recognized in other comprehensive income (before taxes)		(7)	(6)	(2)
Net impairment losses recognized in earnings		3	4	2
Other-than-temporary impairment losses for debt securities		$ 8	$ 6	$ 2

[1] Amounts include other-than-temporary impairment losses for debt securities of $13 million, $9 million and $3 million at December 31, 2016, 2015 and 2014, respectively.

[2] Comprised of Dominion Midstream's interest of 25.93% and Dominion Gas' interest of 24.07%. See Note 15 for more information.