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Derivatives and Hedge Accounting Activities (Selected Information Related to Gains (Losses) on Cash Flow Hedges Included in AOCI) (Detail) $ in Millions | 12 Months Ended
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Dec. 31, 2017 USD ($)
Derivative Instruments Gain Loss [Line Items] |
AOCI After-Tax | $ (302)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax | (73)
Commodity | Electricity |
Derivative Instruments Gain Loss [Line Items] |
AOCI After-Tax | (55)
Commodities, Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax | $ (55)
Maximum Term | 12 months
Commodity | Other Energy Contract |
Derivative Instruments Gain Loss [Line Items] |
AOCI After-Tax | $ (4)
Commodities, Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax | $ (4)
Maximum Term | 15 months
Commodity | Natural Gas |
Derivative Instruments Gain Loss [Line Items] |
AOCI After-Tax | $ (2)
Commodities, Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax | $ (3)
Maximum Term | 34 months
Interest rate |
Derivative Instruments Gain Loss [Line Items] |
AOCI After-Tax | $ (246)
Interest rate, Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax | $ (10)
Maximum Term | 384 months
Foreign currency |
Derivative Instruments Gain Loss [Line Items] |
AOCI After-Tax | $ 5
Foreign currency, Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax | $ (1)
Maximum Term | 102 months
Dominion Energy Gas Holdings, LLC |
Derivative Instruments Gain Loss [Line Items] |
AOCI After-Tax | $ (23)
Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax | (8)
Dominion Energy Gas Holdings, LLC | Interest rate |
Derivative Instruments Gain Loss [Line Items] |
AOCI After-Tax | (25)
Interest rate, Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax | $ (3)
Maximum Term | 324 months
Dominion Energy Gas Holdings, LLC | Foreign currency |
Derivative Instruments Gain Loss [Line Items] |
AOCI After-Tax | $ 6
Foreign currency, Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax | $ (1)
Maximum Term | 102 months
Dominion Energy Gas Holdings, LLC | NGLs |
Derivative Instruments Gain Loss [Line Items] |
AOCI After-Tax | $ (4)
Commodities, Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax | $ (4)
Maximum Term | 15 months
Virginia Electric and Power Company |
Derivative Instruments Gain Loss [Line Items] |
AOCI After-Tax | $ (12)
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 | (12)
Interest rate, Amounts Expected to be Reclassified to Earnings During the Next 12 Months After-Tax | $ (1)
Maximum Term | 384 months

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- Definition 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. + References No definition available. + Details
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- 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=84228862&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=84228862&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=84228862&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=84228862&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
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- Definition The estimated net amount of unrealized gains or losses on foreign currency cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months. + 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 (c) -URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994 + Details
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- 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
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