Commitments and Contingencies (Narrative) (Details) (USD $)	1 Months Ended			9 Months Ended							9 Months Ended				1 Months Ended	50 Months Ended	1 Months Ended
	Jul. 31, 2013 Unit	Sep. 30, 2011 Party	Jul. 31, 2011	Sep. 30, 2014 Site	Sep. 30, 2013	Sep. 30, 2014 Minimum	Sep. 30, 2014 Maximum	Sep. 30, 2014 Third Party and Equity Method Investee	Sep. 30, 2014 Third Party and Equity Method Investee Through 2019	Sep. 30, 2014 Obligated Payments to Maryland Strategic Energy Investments Fund and Low Income Energy Assistance Programs	Sep. 30, 2014 Virginia Electric and Power Company Site	Sep. 30, 2013 Virginia Electric and Power Company	Sep. 30, 2014 Dominion Gas Holdings, LLC Site	Sep. 30, 2013 Dominion Gas Holdings, LLC	Jul. 31, 2011 CAA Group MW State	Sep. 30, 2014 CAA	Oct. 31, 2014 CWA Subsequent Event Facility	Oct. 31, 2014 CWA Subsequent Event Virginia Electric and Power Company Facility	Sep. 30, 2014 Remediation program	Sep. 30, 2014 Breach of Contract Lawsuit Pending Litigation
Investments in and Advances to Affiliates [Line Items]
Number of states under EPA replacement rule															28
Emissions of fossil fuel fired electric generating units (MW)															25
Number of groups of affected states															2
Amount company has spent for emission standards compliance				$ 3,742,000,000	$ 2,955,000,000						$ 2,120,000,000	$ 1,794,000,000	$ 467,000,000	$ 457,000,000		$ 2,000,000
Number of facilities that may be subject to final regulations																	14	11
Number of parties issued UAO		22
Daily civil penalties for non compliance				37,500
Number of former manufactured gas plant sites				17							3		12
Preliminary costs for options under evaluation for site, minimum																			1,000,000
Preliminary costs for options under evaluation for site, maximum																			22,000,000
Maximum period for consideration of CO2 emissions from biomass projects			3 years
Number of coal fired generating units	3
Accrued liability for legal matter																				6,000,000
Total required payments										48,000,000
Amount of civil penalty								69,000,000
Exposure under guarantees				4,533,000,000				54,000,000	72,000,000
Annual future contributions						4,000,000	19,000,000
Purchased surety bonds				134,000,000							63,000,000		31,000,000
Authorized issuance of standby letters of credit				$ 31,000,000