Significant Financing Transactions (Narrative) (Details)		1 Months Ended			3 Months Ended		6 Months Ended
		Jul. 31, 2017 USD ($) shares	Jun. 30, 2017 USD ($) facility agreement	May 31, 2017 USD ($)	Jun. 30, 2017 USD ($) facility shares	Jun. 30, 2016 shares	Jun. 30, 2017 USD ($) facility shares	Jun. 30, 2016 USD ($) shares	Mar. 31, 2017 USD ($)	Jan. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Facility Limit			$ 5,500,000,000		$ 5,500,000,000		$ 5,500,000,000
Short-term debt			$ 2,833,000,000		2,833,000,000		2,833,000,000				$ 3,155,000,000	[1]
Repayments of term loan							0	$ 600,000,000
Issuance of common stock							156,000,000	$ 1,458,000,000
Shelf Registration for Sale of Common Stock through At-the-market Program
Debt Instrument [Line Items]
Number of sales agency agreements | agreement			3
Issuance of common stock			$ 0
Shelf Registration for Sale of Common Stock through At-the-market Program | Maximum
Debt Instrument [Line Items]
Sale of stock authorized amount			500,000,000
Subsequent Event | 2014 Equity Units
Debt Instrument [Line Items]
Issuance of common stock (in shares) | shares		12,500,000
Senior Notes, Due in 2019 | Senior Notes
Debt Instrument [Line Items]
Total Long-term Debt										$ 400,000,000
Interest rate percentage										1.875%
Senior Notes, Due in 2022 | Senior Notes
Debt Instrument [Line Items]
Total Long-term Debt										$ 400,000,000
Interest rate percentage										2.75%
Senior Notes, Due in 2024 | Senior Notes
Debt Instrument [Line Items]
Total Long-term Debt									$ 300,000,000
Interest rate percentage									3.496%
Senior Notes, Due in 2025 | Senior Notes
Debt Instrument [Line Items]
Total Long-term Debt									$ 100,000,000
Interest rate percentage									3.90%
Senior Notes, Due in 2027 | Senior Notes
Debt Instrument [Line Items]
Total Long-term Debt									$ 750,000,000
Interest rate percentage									3.50%
Term Loan, Due in 2024
Debt Instrument [Line Items]
Borrowings under term loan agreement				$ 280,000,000
Term loan, period of amortization				18 years
Debt maturity month and year				2024-05
Senior Notes, Due in 2019 | Senior Notes
Debt Instrument [Line Items]
Total Long-term Debt			$ 500,000,000		$ 500,000,000		$ 500,000,000
Debt maturity year			2019
Massachusetts Development Finance Agency Solid Waste Disposal Revenue Bonds, Series 2010B, Due in 2041
Debt Instrument [Line Items]
Debt maturity month and year			2017-08
Retirement of variable rate bonds			$ 75,000,000
Term Loan | Dominion Energy Questar Corporation | Subsequent Event
Debt Instrument [Line Items]
Debt maturity month and year		2017-08
Repayments of term loan		$ 250,000,000
Series A Remarketable Subordinated Notes
Debt Instrument [Line Items]
Total Long-term Debt				$ 1,000,000,000
Interest rate percentage				1.50%
Series A Remarketable Subordinated Notes | Junior Subordinated Notes
Debt Instrument [Line Items]
Interest rate percentage				2.579%
Questar Gas | Joint Revolving Credit Facility 5 Billion and Joint Revolving Credit Facility 500 Million
Debt Instrument [Line Items]
Number of joint revolving credit facilities | facility			2		2		2
Facility Limit			$ 250,000,000		$ 250,000,000		$ 250,000,000
SBL Holdco | Credit Facilities, Maturing in December 2017 with 1 year Automatic Renewals through 2023
Debt Instrument [Line Items]
Facility Limit			30,000,000		30,000,000		$ 30,000,000
Automatic renewal period							1 year
SBL Holdco | Credit Facilities, Maturing in December 2017 with 1 year Automatic Renewals through 2023 | Line of Credit
Debt Instrument [Line Items]
Short-term debt			0		0		$ 0
Dominion Solar Projects III, Inc | Credit Facilities, Maturing in May 2018 with 1 year Automatic Renewals through 2024
Debt Instrument [Line Items]
Facility Limit			25,000,000		25,000,000		$ 25,000,000
Automatic renewal period							1 year
Dominion Solar Projects III, Inc | Credit Facilities, Maturing in May 2018 with 1 year Automatic Renewals through 2024 | Line of Credit
Debt Instrument [Line Items]
Short-term debt			$ 0		$ 0		$ 0
Virginia Electric and Power Company
Debt Instrument [Line Items]
Number of joint revolving credit facilities | facility			2		2		2
Facility Limit	[2]		$ 5,500,000,000		$ 5,500,000,000		$ 5,500,000,000
Short-term debt			416,000,000		416,000,000		416,000,000				65,000,000	[3]
Credit facility			100,000,000		100,000,000		100,000,000
Variable rate tax-exempt financings			$ 100,000,000		$ 100,000,000		$ 100,000,000
Issuance of common stock (in shares) | shares					0	0	0	0
Virginia Electric and Power Company | Joint Revolving Credit Facility 5 Billion and Joint Revolving Credit Facility 500 Million
Debt Instrument [Line Items]
Facility Limit				$ 1,500,000,000					$ 2,000,000,000
Dominion Energy Gas Holdings, LLC
Debt Instrument [Line Items]
Number of joint revolving credit facilities | facility			2		2		2
Facility Limit	[4]		$ 1,500,000,000		$ 1,500,000,000		$ 1,500,000,000
Short-term debt			$ 615,000,000		$ 615,000,000		$ 615,000,000				$ 460,000,000	[5]

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

[2] The full amount of the facilities is available to Virginia Power, less any amounts outstanding to co-borrowers Dominion Energy, Dominion Energy Gas and Questar Gas. Sub-limits for Virginia Power are set within the facility limit but can be changed at the option of the Companies multiple times per year. In May 2017, the aggregate sub-limit for Virginia Power was decreased from $2.0 billion to $1.5 billion. If Virginia Power has liquidity needs in excess of its sub-limit, the sub-limit may be changed or such needs may be satisfied through short-term intercompany borrowings from Dominion Energy. These credit facilities mature in April 2020 and can be used to support bank borrowings and the issuance of commercial paper, as well as to support up to $2.0 billion (or the sub-limit, whichever is less) of letters of credit.

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

[4] A maximum of a combined $1.5 billion of the facilities is available to Dominion Energy Gas, assuming adequate capacity is available after giving effect to uses by co-borrowers Dominion Energy, Virginia Power and Questar Gas. Sub-limits for Dominion Energy Gas are set within the facility limit but can be changed at the option of the Companies multiple times per year. In May 2017, the aggregate sub-limit for Dominion Energy Gas was increased from $500 million to $750 million. If Dominion Energy Gas has liquidity needs in excess of its sub-limit, the sub-limit may be changed or such needs may be satisfied through short-term intercompany borrowings from Dominion Energy. These credit facilities mature in April 2020 and can be used to support bank borrowings and the issuance of commercial paper, as well as to support up to $1.5 billion (or the sub-limit, whichever is less) of letters of credit.

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