Investments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			1 Months Ended	3 Months Ended	12 Months Ended			1 Months Ended		3 Months Ended		1 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Blue Racer	Sep. 30, 2013 Blue Racer	Dec. 31, 2013 Blue Racer	Dec. 31, 2012 Blue Racer	Dec. 31, 2011 Blue Racer	Jan. 31, 2014 Blue Racer Subsequent Event	Mar. 31, 2013 Blue Racer Pipelines	Dec. 31, 2013 Blue Racer Pipelines	Sep. 30, 2013 Blue Racer Pipelines	Dec. 31, 2012 Other operations and maintenance expense Blue Racer	Dec. 31, 2013 Virginia Electric and Power Company	Dec. 31, 2012 Virginia Electric and Power Company	Dec. 31, 2013 Categories of Investments, Marketable Securities, Trading Securities	Dec. 31, 2012 Categories of Investments, Marketable Securities, Trading Securities	Dec. 31, 2013 Cost method investments	Dec. 31, 2012 Cost method investments
Gain (Loss) on Investments [Line Items]
Investments held in our rabbi trusts																$ 107	$ 95	$ 10	$ 14
Equity earnings on investments	14	25	35
Company received distribution from Fowler Ridge in connection with non-recourse permanent financing	33	58	55	115		160	115	0
Carrying amount of Company's investments exceeded its shares of underlying equity	36	30
Capitalized interest during construction	28
Equity method goodwill	8
Ownership percentage				50.00%			50.00%
Gain on purchase of business													72
Gain on purchase of business, net of tax													43
Transaction costs on sale													9
Cash proceeds received from sale										47	30	83
Gain from sale										25	4	75
After tax gain on sale										14	2	42
Increase in equity method investment					473
Increase in equity method investment									155
Restricted cash and cash equivalent for funding qualifying projects	$ 11	$ 37												$ 8	$ 10