Earnings Per Share (Calculation of our Basic and Diluted EPS) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net income attributable to Dominion		$ 457	$ 690	$ 452	$ 524	$ 357	$ 593	$ 413	$ 536	$ 2,123	$ 1,899	$ 1,310
Average shares of common stock outstanding-Basic										616.4	592.4	582.7
Net effect of potentially dilutive securities (in shares)	[1]									0.7	1.3	1.8
Average shares of common stock outstanding-Diluted										617.1	593.7	584.5
Earnings Per Common Share-Basic (in dollars per share)		$ 0.73	$ 1.10	$ 0.73	$ 0.88	$ 0.60	$ 1.00	$ 0.70	$ 0.91	$ 3.44	$ 3.21	$ 2.25
Earnings Per Common Share-Diluted (in dollars per share)		$ 0.73	$ 1.10	$ 0.73	$ 0.88	$ 0.60	$ 1.00	$ 0.70	$ 0.91	$ 3.44	$ 3.20	$ 2.24

[1] Dilutive securities consist primarily of the 2013 Equity Units for 2016 and 2015 and the 2013 Equity Units and contingently convertible senior notes for 2014. Dominion redeemed all of its contingently convertible senior notes in 2014. See Note 17 for more information.