Investments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended							6 Months Ended			1 Months Ended
	Jan. 31, 2014 Blue Racer	Mar. 31, 2014 Blue Racer Pipelines	Mar. 31, 2013 Blue Racer Pipelines	Jun. 30, 2014 Categories of Investments, Marketable Securities, Trading Securities	Dec. 31, 2013 Categories of Investments, Marketable Securities, Trading Securities	Jun. 30, 2014 Cost method investments	Dec. 31, 2013 Cost method investments	Jun. 30, 2014 Dominion Gas Holdings, LLC	Jun. 30, 2013 Dominion Gas Holdings, LLC	Dec. 31, 2013 Dominion Gas Holdings, LLC	Mar. 31, 2014 Dominion Gas Holdings, LLC Blue Racer Pipelines
Gain (Loss) on Investments [Line Items]
Assets Held-in-trust				$ 109	$ 107	$ 8	$ 10
Equity in earnings on investments								13	13
Distributions received from investment								5	5
Carrying amount of investment that exceeded share of underlying equity								9		8
Cash proceeds from sale of assets		84	47								17
Gain on sale of assets			25								59
After tax gain on sale of assets		34	14								35
Extinguishment of affiliated current borrowings											67
Write off of goodwill	6		2								3
Increase in equity method investment	155
Consideration for Northern System		$ 84