Earnings Per Share (Calculation of Basic and Diluted EPS) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net income attributable to Dominion		$ 593	$ 529	$ 1,542	$ 1,067
Average shares of common stock outstanding – Basic (shares)		594.6	583.1	591.3	582.2
Net effect of potentially dilutive securities (shares)	[1]	0.9	1.5	1.4	1.6
Average shares of common stock outstanding – Diluted (shares)		595.5	584.6	592.7	583.8
Earnings Per Common Share – Basic (in dollars per share)		$ 1.00	$ 0.91	$ 2.61	$ 1.83
Earnings Per Common Share – Diluted (in dollars per share)		$ 1.00	$ 0.90	$ 2.60	$ 1.83

[1] Dilutive securities consist primarily of the 2013 Equity Units for 2015 and contingently convertible senior notes and the 2013 Equity Units for 2014. See Note 15 in this report and Note 17 to the Consolidated Financial Statements in the Companies' Annual Report on Form 10-K for the year ended December 31, 2014 for more information.