Significant Financing Transactions (Commercial Paper, Bank Loans and Letters of Credit Outstanding) (Details) - USD ($)		9 Months Ended
		Sep. 30, 2016	Sep. 01, 2016
Line of Credit Facility [Line Items]
Facility Limit		$ 6,250,000,000
Outstanding Commercial Paper		3,097,000,000
Outstanding Letters of Credit		60,000,000
Facility Capacity Available		3,093,000,000
Virginia Electric and Power Company
Line of Credit Facility [Line Items]
Facility Limit	[1]	5,500,000,000
Outstanding Commercial Paper		965,000,000
Outstanding Letters of Credit		0
Dominion Gas Holdings, LLC
Line of Credit Facility [Line Items]
Facility Limit	[2]	1,500,000,000
Outstanding Commercial Paper		60,000,000
Outstanding Letters of Credit		0
Joint Revolving Credit Facility 4 Billion and Joint Revolving Credit Facility 500 Million | Virginia Electric and Power Company
Line of Credit Facility [Line Items]
Facility Limit		2,000,000,000.0
Joint Revolving Credit Facility 4 Billion and Joint Revolving Credit Facility 500 Million | Dominion Gas Holdings, LLC
Line of Credit Facility [Line Items]
Facility Limit		1,500,000,000.0
Joint Revolving Credit Facility 4 Billion and Joint Revolving Credit Facility 500 Million | Line of Credit | Dominion Gas Holdings, LLC
Line of Credit Facility [Line Items]
Facility Limit		750,000,000	$ 1,000,000,000.0
Joint Revolving Credit Facility 4 Billion and Joint Revolving Credit Facility 500 Million | Letter of Credit
Line of Credit Facility [Line Items]
Facility Limit		2,000,000,000.0
Joint Revolving Credit Facility 4 Billion and Joint Revolving Credit Facility 500 Million | Letter of Credit | Virginia Electric and Power Company
Line of Credit Facility [Line Items]
Facility Limit		2,000,000,000.0
Joint Revolving Credit Facility 4 Billion and Joint Revolving Credit Facility 500 Million | Letter of Credit | Dominion Gas Holdings, LLC
Line of Credit Facility [Line Items]
Facility Limit		1,500,000,000.0
Credit Facility 4 Billion
Line of Credit Facility [Line Items]
Facility Limit	[3]	5,000,000,000
Outstanding Commercial Paper	[3]	3,073,000,000
Outstanding Letters of Credit	[3]	0
Facility Capacity Available	[3]	1,927,000,000
Credit Facility 4 Billion | Virginia Electric and Power Company
Line of Credit Facility [Line Items]
Facility Limit	[1]	5,000,000,000
Outstanding Commercial Paper	[1]	965,000,000
Outstanding Letters of Credit	[1]	0
Credit Facility 4 Billion | Dominion Gas Holdings, LLC
Line of Credit Facility [Line Items]
Facility Limit	[2]	1,000,000,000
Outstanding Commercial Paper	[2]	60,000,000
Outstanding Letters of Credit	[2]	0
Credit Facility 500 Million
Line of Credit Facility [Line Items]
Facility Limit	[3]	500,000,000
Outstanding Commercial Paper	[3]	0
Outstanding Letters of Credit	[3]	60,000,000
Facility Capacity Available	[3]	440,000,000
Credit Facility 500 Million | Virginia Electric and Power Company
Line of Credit Facility [Line Items]
Facility Limit	[1]	500,000,000
Outstanding Commercial Paper	[1]	0
Outstanding Letters of Credit	[1]	0
Credit Facility 500 Million | Dominion Gas Holdings, LLC
Line of Credit Facility [Line Items]
Facility Limit	[2]	500,000,000
Outstanding Commercial Paper	[2]	0
Outstanding Letters of Credit	[2]	0
Revolving multi-year credit facility | Dominion Questar Corporation
Line of Credit Facility [Line Items]
Facility Limit	[4]	500,000,000
Outstanding Commercial Paper	[4]	24,000,000
Outstanding Letters of Credit	[4]	0
Facility Capacity Available	[4]	476,000,000
Revolving 364-day credit facility | Dominion Questar Corporation
Line of Credit Facility [Line Items]
Facility Limit	[4]	250,000,000
Outstanding Commercial Paper	[4]	0
Outstanding Letters of Credit	[4]	0
Facility Capacity Available	[4]	$ 250,000,000
Term of revolving credit facility	[4]	364 days

[1] The full amount of the facilities is available to Virginia Power, less any amounts outstanding to co-borrowers Dominion and Dominion 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. At September 30, 2016, the aggregate sub-limit for Virginia Power was $2.0 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. In May 2016, the maturity dates for these facilities were extended from April 2019 to April 2020. These credit facilities 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.

[2] A maximum of a combined $1.5 billion of the facilities is available to Dominion Gas, assuming adequate capacity is available after giving effect to uses by co-borrowers Dominion and Virginia Power. Sub-limits for Dominion Gas are set within the facility limit but can be changed at the option of the Companies multiple times per year. In September 2016, the aggregate sub-limit for Dominion Gas was decreased from $1.0 billion to $750 million. If Dominion 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. In May 2016, the maturity dates for these facilities were extended from April 2019 to April 2020. These credit facilities 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.

[3] In May 2016, the maturity dates for these facilities were extended from April 2019 to April 2020. These credit facilities can be used by the Companies to support bank borrowings and the issuance of commercial paper, as well as to support up to a combined $2.0 billion of letters of credit.

[4] These Dominion Questar facilities were terminated in October 2016.