Derivatives and Hedge Accounting Activities (Selected Information Related to Gains (Losses) on Cash Flow Hedges Included in AOCI) (Details) $ in Millions	9 Months Ended
Sep. 30, 2016 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	$ (261)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	13
Commodity \| Gas Energy Contract
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	(2)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	$ (2)
Maximum Term	39 months
Commodity \| Electricity Energy Contract
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	$ 44
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	$ 42
Maximum Term	15 months
Commodity \| Other Energy Contract
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	$ (1)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	$ (1)
Maximum Term	6 months
Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	$ (304)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	$ (26)
Maximum Term	378 months
Foreign currency
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	$ 2
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	$ 0
Maximum Term	117 months
Virginia Electric and Power Company
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	$ (22)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	(1)
Virginia Electric and Power Company \| Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	(22)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	$ (1)
Maximum Term	378 months
Dominion Gas Holdings, LLC
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	$ (26)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	(3)
Dominion Gas Holdings, LLC \| Commodity \| NGLs
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	(1)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	$ (1)
Maximum Term	6 months
Dominion Gas Holdings, LLC \| Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	$ (27)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	$ (2)
Maximum Term	339 months
Dominion Gas Holdings, LLC \| Foreign currency
Derivative Instruments, Gain (Loss) [Line Items]
AOCI After-Tax	$ 2
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax	$ 0
Maximum Term	117 months

Accumulated change, net of tax, in accumulated gains and losses from instruments designated and qualifying as the effective portion of cash flow hedges that will be reclassified into earnings during the next 12 months.

No definition available.

+ Details

Name:	d_AmountsExpectedToBeReclassifiedToEarningsDuringNext12MonthsAfterTax
Namespace Prefix:	d_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Accumulated change, net of tax, in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e637-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669686-108580

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e681-108580

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80784-113994

+ Details

Name:	us-gaap_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeInstrumentsGainLossLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

+ Details

Name:	us-gaap_MaximumLengthOfTimeHedgedInCashFlowHedge1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CommodityContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	d_CommodityTypeAxis=d_GasEnergyContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	d_CommodityTypeAxis=d_ElectricityEnergyContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	d_CommodityTypeAxis=d_OtherEnergyContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
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:	dei_LegalEntityAxis=d_DominionGasHoldingsLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	d_CommodityTypeAxis=d_NaturalGasLiquidsEnergyContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: