Regulatory Assets and Liabilities (Schedule of Regulatory Assets) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017	Dec. 31, 2016
Regulatory Assets [Line Items]
Regulatory assets-current	[1]	$ 231	$ 244
Regulatory assets-noncurrent		2,439	2,473	[2]
Total regulatory assets		2,670	2,717
Deferred rate adjustment clause costs
Regulatory Assets [Line Items]
Regulatory assets-current	[3]	75	63
Regulatory assets-noncurrent	[3]	328	329
Deferred nuclear refueling outage costs
Regulatory Assets [Line Items]
Regulatory assets-current	[4]	$ 53	71
Deferred nuclear refueling outage costs | Maximum
Regulatory Assets [Line Items]
Amortization period for deferred costs		18 months
Unrecognized pension and other postretirement benefit costs
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[5]	$ 1,328	1,401
PJM transmission rates
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[6]	200	192
Derivatives
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[7]	172	174
Income taxes recoverable through future rates
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[8]	138	123
Utility reform legislation
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[9]	110	99
Other
Regulatory Assets [Line Items]
Regulatory assets-current		103	110
Regulatory assets-noncurrent		163	155
Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets-current	[1]	190	179
Regulatory assets-noncurrent		776	770	[10]
Total regulatory assets		966	949
Virginia Electric and Power Company | Deferred rate adjustment clause costs
Regulatory Assets [Line Items]
Regulatory assets-current	[3]	71	51
Regulatory assets-noncurrent	[3]	232	246
Virginia Electric and Power Company | Deferred nuclear refueling outage costs
Regulatory Assets [Line Items]
Regulatory assets-current	[4]	53	71
Virginia Electric and Power Company | PJM transmission rates
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[6]	200	192
Virginia Electric and Power Company | Derivatives
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[7]	137	133
Virginia Electric and Power Company | Income taxes recoverable through future rates
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[8]	81	76
Virginia Electric and Power Company | Other
Regulatory Assets [Line Items]
Regulatory assets-current		66	57
Regulatory assets-noncurrent		126	123
Dominion Gas Holdings, LLC
Regulatory Assets [Line Items]
Regulatory assets-current	[1]	7	26
Regulatory assets-noncurrent	[11]	550	577
Total regulatory assets		557	603
Dominion Gas Holdings, LLC | Deferred rate adjustment clause costs
Regulatory Assets [Line Items]
Regulatory assets-current	[3]	4	12
Regulatory assets-noncurrent	[3]	89	79
Dominion Gas Holdings, LLC | Unrecovered gas costs
Regulatory Assets [Line Items]
Regulatory assets-current	[12]	0	12
Dominion Gas Holdings, LLC | Unrecognized pension and other postretirement benefit costs
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[5]	305	358
Dominion Gas Holdings, LLC | Income taxes recoverable through future rates
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[8]	25	23
Dominion Gas Holdings, LLC | Utility reform legislation
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[9]	110	99
Dominion Gas Holdings, LLC | Other
Regulatory Assets [Line Items]
Regulatory assets-current		3	2
Regulatory assets-noncurrent		$ 21	$ 18

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

[2] Dominion’s Consolidated Balance Sheet at December 31, 2016 has been derived from the audited Consolidated Balance Sheet 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] 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.

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

[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] 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.

[9] Ohio legislation under House Bill 95, which became effective in September 2011. This law updates natural gas legislation by enabling gas companies to include more up-to-date cost levels when filing rate cases. It also allows gas companies to seek approval of capital expenditure plans under which gas companies can recognize carrying costs on associated capital investments placed in service and can defer the carrying costs plus depreciation and property tax expenses for recovery from ratepayers in the future.

[10] Virginia Power’s Consolidated Balance Sheet at December 31, 2016 has been derived from the audited Consolidated Balance Sheet at that date.

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

[12] Reflects unrecovered gas costs at regulated gas operations, which are recovered through filings with the applicable regulatory authority.