Regulatory Assets and Liabilities (Schedule of Regulatory Assets) (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2016	Dec. 31, 2015
Regulatory Assets [Line Items]
Regulatory assets current	[1]	$ 250	$ 351
Regulatory assets-non-current		2,143	1,865	[2]
Total regulatory assets		2,393	2,216
Deferred rate adjustment clause costs
Regulatory Assets [Line Items]
Regulatory assets current	[3]	101	90
Regulatory assets-non-current	[3]	271	295
Deferred nuclear refueling outage costs
Regulatory Assets [Line Items]
Regulatory assets current	[4]	$ 60	75
Deferred nuclear refueling outage costs | Maximum
Regulatory Assets [Line Items]
Amortization period for deferred costs		18 months
Deferred cost of fuel used in electric generation
Regulatory Assets [Line Items]
Regulatory assets current	[5]	$ 3	111
Other
Regulatory Assets [Line Items]
Regulatory assets current		86	75
Regulatory assets-non-current		203	127
Unrecognized pension and other postretirement benefit costs
Regulatory Assets [Line Items]
Regulatory assets-non-current	[6]	981	1,015
Derivatives
Regulatory Assets [Line Items]
Regulatory assets-non-current	[7]	366	110
PJM transmission rates
Regulatory Assets [Line Items]
Regulatory assets-non-current	[8]	192	192
Income taxes recoverable through future rates
Regulatory Assets [Line Items]
Regulatory assets-non-current	[9]	130	126
Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets current		197	326	[10]
Regulatory assets-non-current		897	667	[10]
Total regulatory assets		1,094	993
Virginia Electric and Power Company | Deferred rate adjustment clause costs
Regulatory Assets [Line Items]
Regulatory assets current	[3]	85	80
Regulatory assets-non-current	[3]	176	213
Virginia Electric and Power Company | Deferred nuclear refueling outage costs
Regulatory Assets [Line Items]
Regulatory assets current	[4]	60	75
Virginia Electric and Power Company | Deferred cost of fuel used in electric generation
Regulatory Assets [Line Items]
Regulatory assets current	[5]	3	111
Virginia Electric and Power Company | Other
Regulatory Assets [Line Items]
Regulatory assets current		49	60
Regulatory assets-non-current		64	55
Virginia Electric and Power Company | Derivatives
Regulatory Assets [Line Items]
Regulatory assets-non-current	[7]	366	110
Virginia Electric and Power Company | PJM transmission rates
Regulatory Assets [Line Items]
Regulatory assets-non-current	[8]	192	192
Virginia Electric and Power Company | Income taxes recoverable through future rates
Regulatory Assets [Line Items]
Regulatory assets-non-current	[9]	99	97
Dominion Gas Holdings, LLC
Regulatory Assets [Line Items]
Regulatory assets current	[1]	22	23
Regulatory assets-non-current	[11]	469	449
Total regulatory assets		491	472
Dominion Gas Holdings, LLC | Deferred rate adjustment clause costs
Regulatory Assets [Line Items]
Regulatory assets current	[3]	16	10
Regulatory assets-non-current	[3]	91	82
Dominion Gas Holdings, LLC | Other
Regulatory Assets [Line Items]
Regulatory assets current		6	13
Regulatory assets-non-current		82	65
Dominion Gas Holdings, LLC | Unrecognized pension and other postretirement benefit costs
Regulatory Assets [Line Items]
Regulatory assets-non-current	[6]	275	282
Dominion Gas Holdings, LLC | Income taxes recoverable through future rates
Regulatory Assets [Line Items]
Regulatory assets-non-current	[9]	$ 21	$ 20

[1] Current regulatory assets are presented in other current assets in Dominion's and Dominion Gas' Consolidated Balance Sheets.

[2] Dominion’s Consolidated Balance Sheet at December 31, 2015 has been derived from the audited Consolidated Financial Statements at that date.

[3] Reflects deferrals under the electric transmission FERC formula rate and the deferral of costs associated with certain current and prospective rider projects for Virginia Power. Reflects deferrals of costs associated with certain current and prospective rider projects for Dominion Gas. See Note 12 for more information.

[4] Legislation enacted in Virginia in April 2014 requires Virginia Power to defer operation and maintenance costs incurred in connection with the refueling of any nuclear-powered generating plant. These deferred costs will be amortized over the refueling cycle, not to exceed 18 months.

[5] Primarily reflects deferred fuel expenses for the Virginia jurisdiction of Dominion's and Virginia Power's generation operations. See Note 12 for more information.

[6] Represents unrecognized pension and other postretirement employee benefit costs expected to be recovered through future rates generally over the expected remaining service period of plan participants by certain of Dominion's and Dominion Gas' rate-regulated subsidiaries

[7] For jurisdictions subject to cost-based rate regulation, changes in the fair value of derivative instruments result in the recognition of regulatory assets or regulatory liabilities as they are expected to be recovered from or refunded to customers.

[8] Reflects amounts related to PJM transmission cost allocation matter. See Note 12 for more information.

[9] Amounts to be recovered through future rates to pay income taxes that become payable when rate revenue is provided to recover AFUDC-equity and depreciation of property, plant and equipment for which deferred income taxes were not recognized for ratemaking purposes, including amounts attributable to tax rate changes.

[10] Virginia Power’s Consolidated Balance Sheet at December 31, 2015 has been derived from the audited Consolidated Financial Statements at that date.

[11] Noncurrent regulatory assets are presented in other deferred charges and other assets in Dominion Gas' Consolidated Balance Sheets