Nature of Operations (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended	1 Months Ended
	Dec. 31, 2014 Segment	Oct. 31, 2014
Subsidiary, Sale of Stock [Line Items]
Number of operating segments	3
Dominion Midstream Partners, LP | IPO
Subsidiary, Sale of Stock [Line Items]
Common units included in initial public offering		20,125,000
Price per unit for units included in initial public offering		$ 21
Net proceeds received from sale of units		$ 392
Percentage of limited partner interests in Dominion Midstream Partners, LP		68.50%
Dominion Midstream Partners, LP | Over-Allotment Option
Subsidiary, Sale of Stock [Line Items]
Common units included in initial public offering		2,625,000
Virginia Electric and Power Company
Subsidiary, Sale of Stock [Line Items]
Number of operating segments	2
Dominion Gas Holdings, LLC
Subsidiary, Sale of Stock [Line Items]
Number of operating segments	1