Property, Plant and Equipment (Narrative) (Details) (Dominion Gas Holdings, LLC, Oil and Gas Properties, USD $) In Millions, unless otherwise specified	1 Months Ended			12 Months Ended
	Nov. 30, 2014 Field acre	Sep. 30, 2014 Field acre	Dec. 31, 2013 Natural_Gas_Producer acre	Dec. 31, 2014	Dec. 31, 2013 acre
Dominion Gas Holdings, LLC | Oil and Gas Properties
Property, Plant and Equipment [Line Items]
Number of natural gas producers			2
Acres of Marcellus Shale development rights	11,000	24,000	100,000		100,000
Agreed upon payments for conveyance of acres of natural gas storage fields	$ 27	$ 120	$ 200		$ 200
Period for payments related to conveyance of natural gas storage fields		4 years	9 years
Cash proceeds received from sale	60			16	100
Gain from sale	60				20
After tax gain on sale	36				12
Total deferred revenue				$ 85
Number of natural gas storage fields	1	1
Number of acres included in initial conveyance	12,000