Fair Value Measurements Fair Value Measurements (Narrative) (Details) (USD $)	1 Months Ended	9 Months Ended		1 Months Ended		1 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Jun. 30, 2013 Project	Sep. 30, 2014	Sep. 30, 2013	Jun. 30, 2013 Other Operations And Maintenance Expense	Jun. 30, 2013 Gas, Transmission and Distribution Equipment Fair Value, Measurements, Nonrecurring Level 3	Jun. 30, 2013 Gas, Transmission and Distribution Equipment Other Operations And Maintenance Expense	Sep. 30, 2014 Virginia Electric and Power Company	Sep. 30, 2013 Virginia Electric and Power Company	Sep. 30, 2014 Virginia Electric and Power Company	Sep. 30, 2013 Virginia Electric and Power Company	Sep. 30, 2014 Dominion Gas Holdings, LLC	Sep. 30, 2013 Dominion Gas Holdings, LLC	Sep. 30, 2014 Dominion Gas Holdings, LLC	Sep. 30, 2013 Dominion Gas Holdings, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of merchant generation assets		$ 0	$ 48,000,000			$ 49,000,000								$ 55,000,000
Impairment charge, net of tax						29,000,000								33,000,000
Estimated fair values of certain natural gas infrastructure facilities					1,000,000
Impairment charge				6,000,000
Write off of previously capitalized costs, net of tax				4,000,000
Number of development projects canceled	2
Unrealized gains or losses included in earnings in Level 3 fair value category							$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0