Regulatory Assets and Liabilities (Narrative) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017	Dec. 31, 2016
Public Utilities, General Disclosures [Line Items]
Regulatory assets past expenditures not earning return		$ 295
Regulatory assets		$ 2,439	$ 2,473	[1]
Period for which expenditures are expected to be recovered		2 years
PJM transmission rates
Public Utilities, General Disclosures [Line Items]
Regulatory assets	[2]	$ 200	192
Virginia Electric and Power Company
Public Utilities, General Disclosures [Line Items]
Regulatory assets past expenditures not earning return		230
Regulatory assets		776	770	[3]
Virginia Electric and Power Company | PJM transmission rates
Public Utilities, General Disclosures [Line Items]
Regulatory assets	[2]	$ 200	$ 192

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

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

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