Income Taxes (Reconciliation of Income Taxes at the U.S. Statutory Federal Rate as Compared to the Income Tax Expense Recorded in Our Consolidated Statements of Income) (Details)	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016
Income Taxes [Line Items]
U.S. statutory rate	35.00%	35.00%
Increases (reductions) resulting from:
State taxes, net of federal benefit	2.80%	4.30%
Investment tax credits	(5.50%)	(9.90%)
Production tax credits	(0.80%)	(0.80%)
State legislative change	0.00%	(1.30%)
AFUDC - equity	(1.40%)	(0.70%)
Other, net	(2.60%)	(1.60%)
Effective tax rate	27.50%	25.00%
Virginia Electric and Power Company
Income Taxes [Line Items]
U.S. statutory rate	35.00%	35.00%
Increases (reductions) resulting from:
State taxes, net of federal benefit	3.70%	4.00%
Investment tax credits	(0.80%)	(0.00%)
Production tax credits	(0.50%)	(0.60%)
State legislative change	0.00%	0.00%
AFUDC - equity	(0.60%)	(0.70%)
Other, net	(0.10%)	0.20%
Effective tax rate	36.70%	37.90%
Dominion Energy Gas Holdings, LLC
Income Taxes [Line Items]
U.S. statutory rate	35.00%	35.00%
Increases (reductions) resulting from:
State taxes, net of federal benefit	1.50%	3.80%
Investment tax credits	(0.00%)	(0.00%)
Production tax credits	(0.00%)	(0.00%)
State legislative change	0.00%	0.00%
AFUDC - equity	(1.00%)	(0.20%)
Other, net	0.00%	0.10%
Effective tax rate	35.50%	38.70%

Effective income tax rate reconciliation allowance for funds used during construction equity.

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Effective income tax rate reconciliation change in state legislation percent.

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Income taxes.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deduction for qualified production activity.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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