Operating Segments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
After-tax net expenses					$ 8,110	$ 8,147	$ 9,715
Charges associated with future ash pond and landfill closure costs					197	99	121
Charge recognized					0	0	374
Facilities Subject to Coal Combustion Residual Final Rule
Segment Reporting Information [Line Items]
Charge related to future ash pond and landfill closure costs	$ 122
Virginia Electric and Power Company
Segment Reporting Information [Line Items]
After-tax net expenses					5,238	5,501	5,855
Charges associated with future ash pond and landfill closure costs					197	99	121
Charge recognized					0	0	374
Virginia Electric and Power Company | Virginia Regulation | Deferred Fuel Costs
Segment Reporting Information [Line Items]
Write off of deferred fuel cost, net of tax				$ 52
Virginia Electric and Power Company | Facilities Subject to Coal Combustion Residual Final Rule
Segment Reporting Information [Line Items]
Charge related to future ash pond and landfill closure costs	$ 121	$ 32	$ 28
Dominion Gas Holdings, LLC
Segment Reporting Information [Line Items]
After-tax net expenses					969	927	1,047
Operating Segments | Organizational Design Initiative
Segment Reporting Information [Line Items]
Organizational design initiative charges					59
Organizational design initiative charges, after tax					36
Operating Segments | Corporate and Other
Segment Reporting Information [Line Items]
After-tax net expenses					484	391	970
Net expenses attributable to other operating segments					180	136	544
Operating Segments | Dominion Generation
Segment Reporting Information [Line Items]
Charges associated with future ash pond and landfill closure costs							121
Charge related to future ash pond and landfill closure costs							74
Operating Segments | Dominion Generation | Legislation enacted
Segment Reporting Information [Line Items]
Charge recognized							374
Charge recognized, net of tax							248
Operating Segments | Dominion Generation | Virginia Regulation | Deferred Fuel Costs
Segment Reporting Information [Line Items]
Write offs of deferred fuel costs						85
Write off of deferred fuel cost, net of tax						52
Operating Segments | Dominion Generation | Organizational Design Initiative
Segment Reporting Information [Line Items]
Organizational design initiative charges, after tax					19
Operating Segments | Dominion Generation | Facilities Subject to Coal Combustion Residual Final Rule
Segment Reporting Information [Line Items]
Charges associated with future ash pond and landfill closure costs					197	99
Charge related to future ash pond and landfill closure costs					122	60
Operating Segments | DVP | Organizational Design Initiative
Segment Reporting Information [Line Items]
Organizational design initiative charges, after tax					5
Operating Segments | Dominion Energy | Legislation enacted
Segment Reporting Information [Line Items]
Charge recognized							319
Charge recognized, net of tax							193
Operating Segments | Dominion Energy | Organizational Design Initiative
Segment Reporting Information [Line Items]
Organizational design initiative charges, after tax					12
Operating Segments | Virginia Electric and Power Company | Corporate and Other
Segment Reporting Information [Line Items]
After-tax net expenses					173	153	342
Operating Segments | Virginia Electric and Power Company | Dominion Generation
Segment Reporting Information [Line Items]
Charges associated with future ash pond and landfill closure costs							121
Charge related to future ash pond and landfill closure costs							74
Operating Segments | Virginia Electric and Power Company | Dominion Generation | Legislation enacted
Segment Reporting Information [Line Items]
Charge recognized							374
Charge recognized, net of tax							248
Operating Segments | Virginia Electric and Power Company | Dominion Generation | Virginia Regulation | Deferred Fuel Costs
Segment Reporting Information [Line Items]
Write offs of deferred fuel costs						85
Write off of deferred fuel cost, net of tax						52
Operating Segments | Virginia Electric and Power Company | Dominion Generation | Facilities Subject to Coal Combustion Residual Final Rule
Segment Reporting Information [Line Items]
Charges associated with future ash pond and landfill closure costs					197	99
Charge related to future ash pond and landfill closure costs					121	60
Operating Segments | Dominion Gas Holdings, LLC
Segment Reporting Information [Line Items]
Net expenses attributable to other operating segments					7	13
Ceiling test impairment charge						16
Ceiling test impairment charge, net of tax						10
Operating Segments | Dominion Gas Holdings, LLC | Organizational Design Initiative
Segment Reporting Information [Line Items]
Organizational design initiative charges					8
Organizational design initiative charges, after tax					5
Operating Segments | Dominion Gas Holdings, LLC | Corporate and Other
Segment Reporting Information [Line Items]
Net expenses attributable to other operating segments					$ 3	$ 21	$ 9