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Investments (Portion of Unrealized Gains and Losses Relates to Equity Securities) (Detail) $ in Millions | 3 Months Ended
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Mar. 31, 2018 USD ($)
Investment Holdings [Line Items] |  |
Net losses recognized during the period | $ (65) |
Less: Net gains recognized during the period on securities sold during the period | (19) |
Unrealized gain (loss) on securities recorded in other income, before tax | (84) | [1]
Virginia Electric and Power Company |  |
Investment Holdings [Line Items] |  |
Net losses recognized during the period | (32) |
Less: Net gains recognized during the period on securities sold during the period | (15) |
Unrealized gain (loss) on securities recorded in other income, before tax | $ (47) | [1]
[1] | Included in other income and the nuclear decommissioning trust regulatory liability as discussed in Note 2.

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- Definition Net gains and losses recognized on equity securities. + References No definition available. + Details
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- Definition The difference between the carrying value and the sale price of equity securities, not separately or otherwise categorized as trading or available-for-sale. This element includes investments in which the entity holds a small ownership stake (generally, less than 20% of the shares outstanding) and cannot exert significant influence. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.13(h)) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 + Details
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- 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
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- Definition Amount of unrealized gain (loss) recognized in the income statement on unsold other securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 + Details
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