Significant Accounting Policies (Depreciation Rates and Estimated Useful Life) (Details)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Generation [Member]
Depreciation rates	2.68%	2.59%	2.62%
Transmission [Member]
Depreciation rates	2.26%	2.24%	2.27%
Distribution [Member]
Depreciation rates	3.19%	3.20%	3.21%
Storage [Member]
Depreciation rates	2.64%	2.75%	2.83%
Gas Gathering and Processing [Member]
Depreciation rates	2.52%	2.39%	2.18%
General and Other [Member]
Depreciation rates	4.66%	4.60%	4.33%
General and Other [Member] | Dominion [Member]
Estimated useful life, minimum	3
Estimated useful life, maximum	25
Merchant Generation- Nuclear [Member] | Dominion [Member]
Estimated useful life, minimum	29
Estimated useful life, maximum	44
Merchant Generation- Other [Member] | Dominion [Member]
Estimated useful life, minimum	27
Estimated useful life, maximum	40