Variable Interest Entities (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) MW generator	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Variable Interest Entity [Line Items]
Securities due within one year	$ 4,050		$ 4,050		$ 1,709	[1]
Long term debt	30,155		30,155		30,231	[1]
Virginia Electric and Power Company
Variable Interest Entity [Line Items]
Securities due within one year	1,451		1,451		678	[2]
Long term debt	9,749		9,749		9,852	[2]
Dominion Energy Gas Holdings, LLC
Variable Interest Entity [Line Items]
Long term debt	3,553		3,553		3,528	[3]
Variable Interest Entity, Primary Beneficiary | SBL Holdco
Variable Interest Entity [Line Items]
Securities due within one year	27		$ 27
Long term debt					$ 358
Variable Interest Entity (VIE) or Potential VIE, Information Unavailability | Virginia Electric and Power Company
Variable Interest Entity [Line Items]
Long term capacity contract non utility generators (generators) | generator			3
Aggregate generation capacity from long-term power and capacity contracts (MW) | MW			418
Remaining purchase commitments	231		$ 231
Payment for electric capacity	28	$ 37	56	$ 74
Payment for electric energy	7	5	15	12
Variable Interest Entity, Not Primary Beneficiary | Virginia Electric and Power Company | DES
Variable Interest Entity [Line Items]
Shared services purchased	83	74	168	188
Variable Interest Entity, Not Primary Beneficiary | Dominion Energy Gas Holdings, LLC | DES
Variable Interest Entity [Line Items]
Shared services purchased	$ 31	$ 29	$ 62	$ 64

[1] Dominion Energy’s Consolidated Balance Sheet at December 31, 2016 has been derived from the audited Consolidated Balance Sheet at that date.

[2] Virginia Power’s Consolidated Balance Sheet at December 31, 2016 has been derived from the audited Consolidated Balance Sheet at that date.

[3] Dominion Energy Gas’ Consolidated Balance Sheet at December 31, 2016 has been derived from the audited Consolidated Balance Sheet at that date.