Long-Term Debt (Total Long Term Debt) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
2016 Weighted- average Coupon (percentage)	[1],[2]	3.13%
Total principal		$ 32,192,000,000	$ 25,473,000,000
Securities due within one year	[1]	(1,709,000,000)	(1,825,000,000)
Unamortized discount and debt issuance costs		(251,000,000)	(187,000,000)
Total long term debt		30,231,000,000	23,468,000,000
Fair value hedge valuation, liability	[3]	(1,000,000)
Fair value hedge valuation, asset	[3]		7,000,000
Variable Rate Short Term Notes Maturing in May 2016 | Promissory note
Debt Instrument [Line Items]
Principal amount of notes			100,000,000
Senior Notes | Variable rate, due 2016
Debt Instrument [Line Items]
Total principal		$ 0	600,000,000
Senior Notes | 1.25% to 6.4%, due 2016 to 2021
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		1.25%
Interest rate, maximum (percentage)		6.40%
2016 Weighted- average Coupon (percentage)	[2]	2.83%
Total principal		$ 5,400,000,000	3,900,000,000
Senior Notes | 2.75% to 7.0%, due 2022 to 2044
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		2.75%
Interest rate, maximum (percentage)		7.00%
2016 Weighted- average Coupon (percentage)	[2]	4.68%
Total principal		$ 4,999,000,000	4,599,000,000
Senior Notes | 6.8% and 6.875%, due 2026 and 2027(4)
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		6.80%
Interest rate, maximum (percentage)		6.875%
2016 Weighted- average Coupon (percentage)	[2],[4]	6.81%
Total principal	[4]	$ 89,000,000	89,000,000
Senior Notes | 5.31% to 6.85%, due 2017 and 2018
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		5.31%
Interest rate, maximum (percentage)		6.85%
2016 Weighted- average Coupon (percentage)	[2],[5]	5.84%
Total principal	[5]	$ 135,000,000	0
Senior Notes | 2.98% to 7.20%, due 2024 to 2051
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		2.98%
Interest rate, maximum (percentage)		7.20%
2016 Weighted- average Coupon (percentage)	[2],[5]	4.57%
Total principal	[5]	$ 500,000,000	0
Junior Subordinated Notes | 2.962% and 4.104%, due 2019 and 2021
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		2.962%
Interest rate, maximum (percentage)		4.104%
2016 Weighted- average Coupon (percentage)	[2]	3.53%
Total principal		$ 1,100,000,000	0
Junior Subordinated Notes | Payable to Affiliated Trust, 8.4% due 2031
Debt Instrument [Line Items]
2016 Weighted- average Coupon (percentage)	[2]	8.40%
Interest rate (percentage)		8.40%
Total principal		$ 10,000,000	10,000,000
Junior Subordinated Notes | 5.25% to 7.5%, due 2054 to 2076
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		5.25%
Interest rate, maximum (percentage)		7.50%
2016 Weighted- average Coupon (percentage)	[2]	5.48%
Total principal		$ 1,485,000,000	971,000,000
Junior Subordinated Notes | Variable rates, due 2066
Debt Instrument [Line Items]
2016 Weighted- average Coupon (percentage)	[2]	3.45%
Total principal		$ 422,000,000	377,000,000
Term Loans | Tax-Exempt Financing, variable rate, due 2041
Debt Instrument [Line Items]
2016 Weighted- average Coupon (percentage)	[2]	1.41%
Total principal		$ 75,000,000	75,000,000
Term Loans | Term loan, variable rate, due 2017
Debt Instrument [Line Items]
2016 Weighted- average Coupon (percentage)	[2],[4],[5]	1.85%
Total principal	[4],[5]	$ 250,000,000	0
Term Loans | Term Loan, variable rate, due 2023
Debt Instrument [Line Items]
2016 Weighted- average Coupon (percentage)	[2],[6]	4.75%
Total principal	[6]	$ 405,000,000	0
Term Loans | Tax-Exempt Financing, 1.55%, due 2033
Debt Instrument [Line Items]
2016 Weighted- average Coupon (percentage)	[2],[7]	1.55%
Interest rate (percentage)		1.55%
Total principal	[7]	$ 27,000,000	27,000,000
Remarketable Subordinated Notes | Remarketable Subordinated Notes, 1.07% to 2.0%, due 2019 to 2024
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		1.07%
Interest rate, maximum (percentage)		2.00%
2016 Weighted- average Coupon (percentage)	[2]	1.79%
Total principal		$ 2,400,000,000	2,100,000,000
Dominion Gas Holdings, LLC
Debt Instrument [Line Items]
Total principal		3,563,000,000	3,300,000,000
Securities due within one year		0	(400,000,000)
Unamortized discount and debt issuance costs		(35,000,000)	(31,000,000)
Total long term debt		$ 3,528,000,000	2,869,000,000
Dominion Gas Holdings, LLC | Senior Notes | 1.05% to 2.8%, due 2016 to 2020
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		1.05%
Interest rate, maximum (percentage)		2.80%
2016 Weighted- average Coupon (percentage)	[2]	2.68%
Total principal		$ 1,150,000,000	1,550,000,000
Dominion Gas Holdings, LLC | Senior Notes | 2.875% to 4.8%, due 2023 to 2044
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		2.875%
Interest rate, maximum (percentage)		4.80%
2016 Weighted- average Coupon (percentage)	[2],[8]	3.90%
Total principal	[8]	$ 2,413,000,000	1,750,000,000
Virginia Electric and Power Company
Debt Instrument [Line Items]
2016 Weighted- average Coupon (percentage)	[2]	5.47%
Total principal		$ 10,597,000,000	9,425,000,000
Securities due within one year		(678,000,000)	(476,000,000)
Unamortized discount and debt issuance costs		(67,000,000)	(57,000,000)
Total long term debt		9,852,000,000	8,892,000,000
Virginia Electric and Power Company | Line of Credit
Debt Instrument [Line Items]
Credit facility, to support letters of credit		$ 100,000,000
Virginia Electric and Power Company | Senior Notes | 1.2% to 8.625%, due 2016 to 2019
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		1.20%
Interest rate, maximum (percentage)		8.625%
2016 Weighted- average Coupon (percentage)	[2]	4.93%
Total principal		$ 1,804,000,000	2,261,000,000
Virginia Electric and Power Company | Senior Notes | 2.75% to 8.875%, due 2022 to 2046
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		2.75%
Interest rate, maximum (percentage)		8.875%
2016 Weighted- average Coupon (percentage)	[2]	4.59%
Total principal		$ 7,940,000,000	6,292,000,000
Virginia Electric and Power Company | Term Loans | Variable rates, due 2016 to 2027
Debt Instrument [Line Items]
2016 Weighted- average Coupon (percentage)	[2],[9]	1.22%
Total principal	[9]	$ 175,000,000	194,000,000
Virginia Electric and Power Company | Term Loans | 1.75% to 5.6%, due 2023 to 2041
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		1.75%
Interest rate, maximum (percentage)		5.60%
2016 Weighted- average Coupon (percentage)	[2],[9]	2.25%
Total principal	[9]	$ 678,000,000	678,000,000
Dominion Midstream Partners, LP | Senior Notes | Unsecured Senior and Medium Term Notes, 5.83% and 6.48%, due 2018
Debt Instrument [Line Items]
Interest rate, minimum (percentage)		5.83%
Interest rate, maximum (percentage)		6.48%
2016 Weighted- average Coupon (percentage)	[2],[10]	5.84%
Total principal	[10]	$ 255,000,000	0
Dominion Midstream Partners, LP | Senior Notes | Unsecured Senior Note, 4.875%, due 2041
Debt Instrument [Line Items]
2016 Weighted- average Coupon (percentage)	[2],[10]	4.88%
Interest rate (percentage)		4.875%
Total principal	[10]	$ 180,000,000	0
Dominion Midstream Partners, LP | Term Loans | Term Loan, variable rate, due 2019
Debt Instrument [Line Items]
2016 Weighted- average Coupon (percentage)	[2]	2.19%
Total principal		$ 300,000,000	$ 0

[1] 2015 excludes $100 million of variable rate short-term notes that were purchased and cancelled in February 2016 using proceeds from the issuance of long-term debt. The notes would have otherwise matured in May 2016.

[2] Represents weighted-average coupon rates for debt outstanding as of December 31, 2016.

[3] Represents the valuation of certain fair value hedges associated with Dominion's fixed rate debt.

[4] Represents debt assumed by Dominion from the merger of its former CNG subsidiary.

[5] Represents debt obligations of Dominion Questar or Dominion Gas. See Note 3 for more information.

[6] Represents debt associated with SBL Holdco. The debt is nonrecourse to Dominion and is secured by SBL Holdco's interest in certain merchant solar facilities.

[7] Represents debt obligations of a DEI subsidiary.

[8] Beginning June 30, 2016, amount includes foreign currency remeasurement adjustments.

[9] These financings relate to certain pollution control equipment at Virginia Power's generating facilities. Certain variable rate tax-exempt financings are supported by a $100 million credit facility that terminates in April 2020.

[10] Represents debt obligations of Questar Pipeline. See Note 3 for more information.