Income Taxes (Income Tax Expense for Continuing Operations Including Noncontrolling Interests) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ (155)	$ (24)	$ (11)
State	85	75	14
Total current expense (benefit)	(70)	51	3
Federal
Taxes before operating loss carryforwards and investment tax credits	1,050	384	956
Tax utilization (benefit) of operating loss carryforwards	(161)	539	(352)
Investment tax credits	(248)	(134)	(152)
State	50	66	(2)
Total deferred expense	691	855	450
Investment tax credit - gross deferral	35	0	0
Investment tax credit - amortization	(1)	(1)	(1)
Total income tax expense	655	905	452
Virginia Electric and Power Company
Current:
Federal	168	316	85
State	90	92	67
Total current expense (benefit)	258	408	152
Federal
Taxes before operating loss carryforwards and investment tax credits	435	154	381
Tax utilization (benefit) of operating loss carryforwards	(2)	96	0
Investment tax credits	(25)	(11)	0
State	27	13	16
Total deferred expense	435	252	397
Investment tax credit - gross deferral	35	0	0
Investment tax credit - amortization	(1)	(1)	(1)
Total income tax expense	727	659	548
Dominion Gas Holdings, LLC
Current:
Federal	(27)	90	86
State	4	30	32
Total current expense (benefit)	(23)	120	118
Federal
Taxes before operating loss carryforwards and investment tax credits	239	156	192
Tax utilization (benefit) of operating loss carryforwards	(2)	6	0
Investment tax credits	0	0	0
State	1	1	24
Total deferred expense	238	163	216
Investment tax credit - gross deferral	0	0	0
Investment tax credit - amortization	0	0	0
Total income tax expense	$ 215	$ 283	$ 334