Goodwill and Intangible Assets (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Amortization expense for intangible assets	$ 71	$ 72	$ 82
Acquisition of intangible assets	115
Weighted-average amortization period (years)	15 years
Virginia Electric and Power Company
Goodwill [Line Items]
Amortization expense for intangible assets	24	22	22
Acquisition of intangible assets	45
Weighted-average amortization period (years)	14 years
Dominion Gas Holdings, LLC
Goodwill [Line Items]
Amortization expense for intangible assets	17	16	15
Acquisition of intangible assets	$ 8
Weighted-average amortization period (years)	7 years