Goodwill and Intangible Assets (Narrative) (Details) (USD $)	1 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended
	Apr. 30, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Feb. 28, 2010 Dominion [Member]	Dec. 31, 2011 Software Allowances Amortization Period [Member]
Netted after-tax proceeds	$ 1,400,000,000				$ 542,000,000
Loss on sale of Peoples, after tax					140,000,000
Write-off of goodwill	134,000,000				79,000,000
Sale of subsidiary	3,500,000,000
Amortization expense for intangible assets		78,000,000	107,000,000	155,000,000
Acquisition of intangible assets		$ 124,000,000
Weighted-average amortization periods maximum (years)						11