Commitments and Contingencies (Subsidiary Guarantees) (Details)	9 Months Ended
	Sep. 30, 2016 USD ($) guarantee subsidiary
Guarantor Obligations [Line Items]
Stated Limit	$ 6,807,000,000
Value	$ 1,594,000,000	[1]
Number of DEI subsidiaries | subsidiary	2
Purchased surety bonds	$ 147,000,000
Authorized issuance of standby letters of credit	60,000,000
Minimum
Guarantor Obligations [Line Items]
Annual future contributions	4,000,000
Maximum
Guarantor Obligations [Line Items]
Annual future contributions	19,000,000
Third Party and Equity Method Investee
Guarantor Obligations [Line Items]
Amount of civil penalty	73,000,000
Stated Limit	43,000,000
Cove Point
Guarantor Obligations [Line Items]
Stated Limit	$ 150,000,000
Number of guarantees with no stated limit | guarantee	2
Number of guarantees | guarantee	1
Aggregate limit	$ 1,750,000,000
Annual draw limit	175,000,000
Subsidiary Debt
Guarantor Obligations [Line Items]
Stated Limit	27,000,000	[2]
Value	27,000,000	[1],[2]
Commodity Transactions
Guarantor Obligations [Line Items]
Stated Limit	2,081,000,000	[3]
Value	874,000,000	[1],[3]
Nuclear Obligations
Guarantor Obligations [Line Items]
Stated Limit	169,000,000	[4]
Value	94,000,000	[1],[4]
Nuclear Obligations | Millstone
Guarantor Obligations [Line Items]
Stated Limit	150,000,000
Nuclear Obligations | Kewaunee
Guarantor Obligations [Line Items]
Stated Limit	60,000,000
Cove Point
Guarantor Obligations [Line Items]
Stated Limit	1,900,000,000	[5]
Value	0	[1],[5]
Solar
Guarantor Obligations [Line Items]
Stated Limit	1,847,000,000	[6]
Value	539,000,000	[1],[6]
Other
Guarantor Obligations [Line Items]
Stated Limit	783,000,000	[7]
Value	60,000,000	[1],[7]
Through 2019 | Third Party and Equity Method Investee
Guarantor Obligations [Line Items]
Stated Limit	36,000,000
Virginia Electric and Power Company
Guarantor Obligations [Line Items]
Purchased surety bonds	70,000,000
Dominion Gas Holdings, LLC
Guarantor Obligations [Line Items]
Purchased surety bonds	$ 21,000,000

[1] Represents the estimated portion of the guarantee's stated limit that is utilized as of September 30, 2016 based upon prevailing economic conditions and fact patterns specific to each guarantee arrangement. For those guarantees related to obligations that are recorded as liabilities by Dominion's subsidiaries, the value includes the recorded amount.

[2] Guarantee of debt of a DEI subsidiary. In the event of default by the subsidiary, Dominion would be obligated to repay such amounts.

[3] Guarantees related to commodity commitments of certain subsidiaries, including subsidiaries of Virginia Power, Dominion Gas and DEI. These guarantees were provided to counterparties in order to facilitate physical and financial transactions in gas, oil, electricity, pipeline capacity, transportation and related commodities and services. If any of these subsidiaries fail to perform or pay under the contracts and the counterparties seek performance or payment, Dominion would be obligated to satisfy such obligation. Dominion and its subsidiaries receive similar guarantees as collateral for credit extended to others. The value provided includes certain guarantees that do not have stated limits.

[4] Guarantees related to certain DEI subsidiaries' potential retrospective premiums that could be assessed if there is a nuclear incident under Dominion's nuclear insurance programs and guarantees for a DEI subsidiary's and Virginia Power's commitment to buy nuclear fuel. Excludes Dominion's agreement to provide up to $150 million and $60 million to two DEI subsidiaries to pay the operating expenses of Millstone nuclear power station (in the event of a prolonged outage) and Kewaunee nuclear power station, respectively, as part of satisfying certain NRC requirements concerned with ensuring adequate funding for the operations of nuclear power stations. The agreement for Kewaunee nuclear power station also provides for funds through the completion of decommissioning.

[5] Guarantees related to Cove Point, in support of terminal services, transportation and construction. Two of the guarantees have no stated limit, one guarantee has a $150 million limit, and one guarantee has a $1.75 billion aggregate limit with an annual draw limit of $175 million.

[6] Includes guarantees related to solar projects including guarantees that do not have stated limits. Also includes guarantees related to solar projects entered into by DEI on behalf of certain subsidiaries.

[7] Guarantees related to other miscellaneous contractual obligations such as leases, environmental obligations and construction projects. Also includes guarantees related to certain DEI subsidiaries' obligations for equity capital contributions and energy generation associated with Fowler Ridge and NedPower. As of September 30, 2016, Dominion's maximum remaining cumulative exposure under these equity funding agreements is $36 million through 2019 and its maximum annual future contributions could range from approximately $4 million to $19 million. The value provided includes certain guarantees that do not have stated limits.