Commitments and Contingencies (Environmental Matters and Other Legal Matters) (Narrative) (Details)	1 Months Ended								12 Months Ended				65 Months Ended
	Jun. 30, 2015 Party	Apr. 30, 2015 Facility	Oct. 31, 2014 Facility	Jun. 30, 2014 Unit	May. 31, 2014 USD ($)	Jul. 31, 2013 Unit	Sep. 30, 2011 Party	Jul. 31, 2011 State Group MW	Dec. 31, 2015 USD ($) Site Party		Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($) Site	Sep. 30, 2015 Facility
Loss Contingencies [Line Items]
Compliance extension period				1 year
Number of coal fired generating units | Unit				2		3
Capital expenditures									$ 5,575,000,000		$ 5,345,000,000	$ 4,065,000,000
Period for consideration of CO2 emissions for biomass projects								3 years
Number of parties ordered specific remedial action | Party							22
Maximum civil penalties per day									$ 37,500
Number of former manufactured gas plant sites | Site									17				17
Charges associated with future ash pond and landfill closure costs									$ 99,000,000		121,000,000	0
ARO recorded related to future ash pond and landfill closure costs									315,000,000	[1]	40,000,000
Required payments									50,000,000				$ 50,000,000
Obligated Payments to Maryland Strategic Energy Investments Fund and Low Income Energy Assistance Programs
Loss Contingencies [Line Items]
Required payments					$ 48,000,000
Obligated Payments to Maryland Strategic Energy Investments Fund
Loss Contingencies [Line Items]
Required payments					$ 40,000,000
Period of required payments					5 years
Low Income Energy Assistance Programs
Loss Contingencies [Line Items]
Required payments					$ 8,000,000
Period of required payments					20 years
CSAPR
Loss Contingencies [Line Items]
Number of states under EPA Replacement Rule | State								28
Emissions of fossil fuel fired electric generating units | MW								25
Number of groups of affected states | Group								2
National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines
Loss Contingencies [Line Items]
Capital expenditures													2,000,000
Clean Water Act
Loss Contingencies [Line Items]
Number of facilities | Facility			14
Clean Water Act | Final Rule to Revise Effluent Limitations Guidelines for Steam Electric Power Generating Category | EPA
Loss Contingencies [Line Items]
Number of facilities subject to ruling | Facility														8
Remedial options
Loss Contingencies [Line Items]
Estimates for compliance, minimum									1,000,000				1,000,000
Estimates for compliance, maximum									22,000,000				22,000,000
Breach of Contract Lawsuit | Pending Litigation
Loss Contingencies [Line Items]
Amount of accrued liability									6,000,000				$ 6,000,000
Virginia Electric and Power Company
Loss Contingencies [Line Items]
Capital expenditures									$ 2,474,000,000		2,911,000,000	2,394,000,000
Number of former manufactured gas plant sites | Site									3				3
Charges associated with future ash pond and landfill closure costs									$ 99,000,000		121,000,000	0
ARO recorded related to future ash pond and landfill closure costs									289,000,000	[1]	28,000,000
Virginia Electric and Power Company | Notice from Southern Environmental Law Center Alleging Clean Water Act Violations at Possum Point | EPA | Possum Point Power Station | Other operations and maintenance expense
Loss Contingencies [Line Items]
Charges associated with future ash pond and landfill closure costs											121,000,000
Virginia Electric and Power Company | Environmental Protection Agency Final Rule Regulating Management of Coal Combustion Residual | EPA | Facilities Subject to Coal Combustion Residual Final Rule
Loss Contingencies [Line Items]
Number of facilities with CCR | Facility		8
ARO recorded related to future ash pond and landfill closure costs									386,000,000
Virginia Electric and Power Company | Environmental Protection Agency Final Rule Regulating Management of Coal Combustion Residual | EPA | Facilities Subject to Coal Combustion Residual Final Rule | Other operations and maintenance expense
Loss Contingencies [Line Items]
Charges associated with future ash pond and landfill closure costs									99,000,000
Virginia Electric and Power Company | Environmental Protection Agency Final Rule Regulating Management of Coal Combustion Residual | EPA | Facilities Subject to Coal Combustion Residual Final Rule | Other Noncurrent Liabilities
Loss Contingencies [Line Items]
Reversal of contingent liability									121,000,000
Virginia Electric and Power Company | Environmental Protection Agency Final Rule Regulating Management of Coal Combustion Residual | EPA | Facilities Subject to Coal Combustion Residual Final Rule | Remediation Property for Sale, Abandonment or Disposal
Loss Contingencies [Line Items]
Increase in property plant and equipment associated with asset retirement costs									166,000,000
Virginia Electric and Power Company | Clean Water Act
Loss Contingencies [Line Items]
Number of facilities | Facility			11
Dominion Gas Holdings, LLC
Loss Contingencies [Line Items]
Capital expenditures									$ 795,000,000		719,000,000	$ 650,000,000
Number of former manufactured gas plant sites | Site									12				12
ARO recorded related to future ash pond and landfill closure costs									$ 5,000,000		$ 2,000,000
Cove Point | Liquefaction Project | Pending Litigation
Loss Contingencies [Line Items]
Number of parties | Party									2
Cove Point | Liquefaction Project | Judicial Ruling
Loss Contingencies [Line Items]
Number of parties | Party	1

[1] Primarily reflects future ash pond and landfill closure costs at certain utility generation facilities. See Note 22 for further information.