Nature of Operations (Narrative) (Details) (Subsequent Event, USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended
	Oct. 31, 2014
Dominion Midstream Partners, LP | IPO
Subsidiary, Sale of Stock [Line Items]
Common units issued in initial public offering	17,500,000
Price per unit of common units issued in initial public offering	$ 21
Estimated proceeds from sale of units	$ 392
Ownership percentage in Dominion Midstream Partners, LP	68.50%
Dominion Midstream Partners, LP | Over-Allotment Option
Subsidiary, Sale of Stock [Line Items]
Common units issued in initial public offering	2,625,000
Cove Point | IPO | Preferred Equity Interest
Subsidiary, Sale of Stock [Line Items]
Preferred equity interest and general partner interest in Cove Point	$ 50