XML 106 R90.htm IDEA: XBRL DOCUMENT
v3.20.2

Derivatives and Hedge Accounting Activities (Schedule of Amounts Recorded on Balance Sheet Related to Cumulative Basis Adjustments for Fair Value Hedges) (Parenthetical) (Detail) - Designated as Hedging Instrument - Fair Value Hedging - Long-term Debt - USD ($) $ in Millions | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Derivative Instruments And Hedging Activities Disclosures [Line Items] |  |
Discontinued hedging liability | $ (1,100) | $ (397)
Hedging adjustments on discontinued hedging relationships | $ (3) | $ 3

X
- Definition Hedged liability discontinued fair value hedge. + References No definition available. + Details
Name: | d_HedgedLiabilityDiscontinuedFairValueHedge
Namespace Prefix: | d_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount as of the balance sheet date of the unamortized adjustment to the carrying value of an interest-bearing hedged item made under an effective fair value hedge that is amortized upon discontinuation of the fair value hedge. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 25 -Section 35 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=121561968&loc=d3e75592-113984 + Details
Name: | us-gaap_DeferredGainLossOnDiscontinuationOfFairValueHedge
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=us-gaap_LongTermDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |