Operating Segments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Proposed customer settlement	$ 16
Proposed customer settlement, after tax	$ 10
Operating Segments
Segment Reporting Information [Line Items]
After- tax net expenses		$ (1)	$ (26)
Operating Segments | Dominion Energy Gas Holdings, LLC
Segment Reporting Information [Line Items]
Write off of regulatory asset		15
Write off of regulatory asset, after tax		9
Operating Segments | Organizational Design Initiative
Segment Reporting Information [Line Items]
Organizational design initiative			59
Organizational design initiative, after tax			36
Operating Segments | Organizational Design Initiative | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Organizational design initiative			33
Organizational design initiative, after tax			20
Operating Segments | Organizational Design Initiative | Dominion Energy Gas Holdings, LLC
Segment Reporting Information [Line Items]
Organizational design initiative			8
Organizational design initiative, after tax			5
Operating Segments | Corporate and Other
Segment Reporting Information [Line Items]
After- tax net expenses		(10)	(37)
Operating Segments | Corporate and Other | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
After- tax net expenses		(7)	(19)
Operating Segments | Corporate and Other | Dominion Energy Gas Holdings, LLC
Segment Reporting Information [Line Items]
After- tax net expenses		(9)	(2)
Operating Segments | Power Delivery | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Proposed customer settlement		16
Proposed customer settlement, after tax		$ 10
Operating Segments | Power Delivery | Organizational Design Initiative
Segment Reporting Information [Line Items]
Organizational design initiative, after tax			5
Operating Segments | Power Delivery | Organizational Design Initiative | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Organizational design initiative, after tax			5
Operating Segments | Gas Infrastructure | Organizational Design Initiative
Segment Reporting Information [Line Items]
Organizational design initiative, after tax			12
Operating Segments | Power Generation | Organizational Design Initiative
Segment Reporting Information [Line Items]
Organizational design initiative, after tax			19
Operating Segments | Power Generation | Organizational Design Initiative | Virginia Electric and Power Company
Segment Reporting Information [Line Items]
Organizational design initiative, after tax			$ 15