[Line Items] for Significant Accounting Policies [Table]

No definition available.

Name:	d_SignificantAccountingPoliciesLineItems
Namespace Prefix:	d_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Utilities operating expense, increase (decrease) in depreciation and amortization.

+ References

No definition available.

+ Details

Name:	d_UtilitiesOperatingExpenseIncreaseDecreaseInDepreciationAndAmortization
Namespace Prefix:	d_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Utilities operating expense, increase (decrease) in depreciation and amortization, after tax.

+ References

No definition available.

+ Details

Name:	d_UtilitiesOperatingExpenseIncreaseDecreaseInDepreciationAndAmortizationAfterTax
Namespace Prefix:	d_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage investment held by members or limited partners of limited liability company (LLC) or limited partnership (LP).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

+ Details

Name:	us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_ChangeInAccountingEstimateByTypeAxis=d_ChangeinEstimatedUsefulLifeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_ElectricGenerationEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=d_MerchantSolarProjectsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CounterpartyNameAxis=d_TerraNovaRenewablePartnersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=d_FourBrothersSolarLLCGraniteMountainHoldingsLLCAndIronSpringsHoldingsLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=d_DominionEnergyMidstreamPartnersLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=d_CommonAndSubordinatedUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_ConvertiblePreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=d_NrgEnergyIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=d_VirginiaElectricAndPowerCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ChangeInAccountingEstimateByTypeAxis=d_ChangeInDepreciationRatesFromNewDepreciationStudyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2017
Change in Estimated Useful Life \| Merchant generation assets
Significant Accounting Policies [Line Items]
Increase (decrease) in depreciation expense	$ (19)
Increase (decrease) in depreciation expense, after tax	$ (12)
Change in Estimated Useful Life \| Scenario, Forecast \| Merchant generation assets
Significant Accounting Policies [Line Items]
Increase (decrease) in depreciation expense		$ (26)
Increase (decrease) in depreciation expense, after tax		(16)
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Merchant Solar Projects \| Terra Nova Renewable Partners
Significant Accounting Policies [Line Items]
Percentage of equity interest sold to noncontrolling interest owners	33.00%
Four Brothers and Three Cedars
Significant Accounting Policies [Line Items]
Percentage ownership in total units	50.00%
Dominion Energy Midstream Partners, LP \| Common and Subordinated Units
Significant Accounting Policies [Line Items]
Ownership interest percentage of limited partner interests	50.90%
Dominion Energy Midstream Partners, LP \| Convertible Preferred Interests
Significant Accounting Policies [Line Items]
Ownership interest percentage of limited partner interests	37.50%
NRG Energy, Inc \| Four Brothers and Three Cedars \| Disposal Group, Disposed of by Sale, Not Discontinued Operations
Significant Accounting Policies [Line Items]
Percentage of equity interest sold to noncontrolling interest owners	33.00%
Virginia Electric and Power Company \| Change in Depreciation Rates from New Depreciation Study
Significant Accounting Policies [Line Items]
Increase (decrease) in depreciation expense	$ 32
Increase (decrease) in depreciation expense, after tax	$ 20
Virginia Electric and Power Company \| Change in Depreciation Rates from New Depreciation Study \| Scenario, Forecast
Significant Accounting Policies [Line Items]
Increase (decrease) in depreciation expense		40
Increase (decrease) in depreciation expense, after tax		$ 25