Significant Financing Transactions (Commercial Paper, Bank Loans and Letters of Credit Outstanding) (Details)	Jun. 30, 2016 USD ($)
Line of Credit Facility [Line Items]
Facility Limit	$ 5,500,000,000
Outstanding Commercial Paper	3,437,000,000
Outstanding Letters of Credit	52,000,000
Facility Capacity Available	2,011,000,000
Virginia Electric and Power Company
Line of Credit Facility [Line Items]
Facility Limit	5,500,000,000	[1]
Outstanding Commercial Paper	1,423,000,000
Outstanding Letters of Credit	0
Dominion Gas Holdings, LLC
Line of Credit Facility [Line Items]
Facility Limit	1,500,000,000	[2]
Outstanding Commercial Paper	238,000,000
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	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	5,000,000,000	[3]
Outstanding Commercial Paper	3,437,000,000	[3]
Outstanding Letters of Credit	0	[3]
Facility Capacity Available	1,563,000,000	[3]
Credit Facility 4 Billion | Virginia Electric and Power Company
Line of Credit Facility [Line Items]
Facility Limit	5,000,000,000	[1]
Outstanding Commercial Paper	1,423,000,000	[1]
Outstanding Letters of Credit	0	[1]
Credit Facility 4 Billion | Dominion Gas Holdings, LLC
Line of Credit Facility [Line Items]
Facility Limit	1,000,000,000	[2]
Outstanding Commercial Paper	238,000,000	[2]
Outstanding Letters of Credit	0	[2]
Credit Facility 500 Million
Line of Credit Facility [Line Items]
Facility Limit	500,000,000	[3]
Outstanding Commercial Paper	0	[3]
Outstanding Letters of Credit	52,000,000	[3]
Facility Capacity Available	448,000,000	[3]
Credit Facility 500 Million | Virginia Electric and Power Company
Line of Credit Facility [Line Items]
Facility Limit	500,000,000	[1]
Outstanding Commercial Paper	0	[1]
Outstanding Letters of Credit	0	[1]
Credit Facility 500 Million | Dominion Gas Holdings, LLC
Line of Credit Facility [Line Items]
Facility Limit	500,000,000	[2]
Outstanding Commercial Paper	0	[2]
Outstanding Letters of Credit	$ 0	[2]

[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 June 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. At June 30, 2016, the aggregate sub-limit for Dominion Gas was $1.0 billion. 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 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.