Commitments and Contingencies (Narrative) (Details)	1 Months Ended								3 Months Ended	6 Months Ended			12 Months Ended	59 Months Ended
	Apr. 30, 2015 Facility	Dec. 31, 2014 USD ($)	Oct. 31, 2014 Facility	Jun. 30, 2014 Unit	Jul. 31, 2013 Unit	Mar. 31, 2012 refueling_outage	Sep. 30, 2011 Party	Jul. 31, 2011 State Group MW	Jun. 30, 2015 USD ($) Site	Jun. 30, 2015 USD ($) Site		Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2015 USD ($) Site
Investments in and Advances to Affiliates [Line Items]
Extension period for MATS compliance				1 year
Number of coal fired generating units | Unit				2
Requested compliance extension under EPA Administrative Order				1 year
Amount company has spent for emission standards compliance										$ 2,370,000,000		$ 2,389,000,000
Number of parties issued UAO | Party							22
Daily civil penalties for non compliance										$ 37,500
Number of former manufactured gas plant sites | Site									17	17				17
Maximum period for consideration of CO2 emissions from biomass projects								3 years
Obligations incurred during the period										$ 306,000,000	[1]		$ 40,000,000
NRC Safety Enhancements
Investments in and Advances to Affiliates [Line Items]
Number of refueling outages | refueling_outage						2
Implementation period						4 years
Virginia Electric and Power Company
Investments in and Advances to Affiliates [Line Items]
Number of coal fired generating units | Unit					3
Amount company has spent for emission standards compliance										$ 1,292,000,000		1,385,000,000
Number of former manufactured gas plant sites | Site									3	3				3
Obligations incurred during the period										$ 288,000,000	[1]		$ 28,000,000
Virginia Electric and Power Company | Possum Point Power Station | Other Operations and Maintenance Expense
Investments in and Advances to Affiliates [Line Items]
Charge as a result of settlement offer		$ 121,000,000
Virginia Electric and Power Company | Facilities Subject to CCR Final Rule | Environmental Protection Agency Final Rule Regulating Management of CCRs | EPA
Investments in and Advances to Affiliates [Line Items]
Number of facilities with CCR | Facility	8
Obligations incurred during the period									$ 325,000,000
Virginia Electric and Power Company | Facilities Subject to CCR Final Rule | Environmental Protection Agency Final Rule Regulating Management of CCRs | EPA | Other Operations and Maintenance Expense
Investments in and Advances to Affiliates [Line Items]
Charge as a result of settlement offer									45,000,000
Virginia Electric and Power Company | Facilities Subject to CCR Final Rule | Environmental Protection Agency Final Rule Regulating Management of CCRs | ARO's | EPA
Investments in and Advances to Affiliates [Line Items]
Increase in property plant and equipment associated with asset retirement costs									159,000,000
Virginia Electric and Power Company | Facilities Subject to CCR Final Rule | Noncurrent Liabilities | Environmental Protection Agency Final Rule Regulating Management of CCRs | EPA
Investments in and Advances to Affiliates [Line Items]
Reduction in other current liabilities									$ 121,000,000
Dominion Gas Holdings, LLC
Investments in and Advances to Affiliates [Line Items]
Amount company has spent for emission standards compliance										$ 292,000,000		$ 249,000,000
Number of former manufactured gas plant sites | Site									12	12				12
CAA
Investments in and Advances to Affiliates [Line Items]
Number of states under EPA replacement rule | State								28
Emissions of fossil fuel fired electric generating units (MW) | MW								25
Number of groups of affected states | Group								2
CAA | Dominion Gas Holdings, LLC
Investments in and Advances to Affiliates [Line Items]
Amount company has spent for emission standards compliance														$ 2,000,000
CWA
Investments in and Advances to Affiliates [Line Items]
Number of facilities that may be subject to final regulations | Facility			14
CWA | Virginia Electric and Power Company
Investments in and Advances to Affiliates [Line Items]
Number of facilities that may be subject to final regulations | Facility			11
Remediation program | Virginia Electric and Power Company
Investments in and Advances to Affiliates [Line Items]
Preliminary costs for options under evaluation for site, minimum									$ 1,000,000	$ 1,000,000				1,000,000
Preliminary costs for options under evaluation for site, maximum									22,000,000	22,000,000				22,000,000
Breach of Contract Lawsuit | DTI | Pending Litigation
Investments in and Advances to Affiliates [Line Items]
Accrued liability for legal matter									$ 6,000,000	$ 6,000,000				$ 6,000,000

[1] Primarily reflects future ash pond and landfill closure costs at certain utility generation facilities. See Note 16 for further information.