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Derivative Instruments (Effect Of Derivative Instruments On Consolidated Statements Of Operations) (Detail) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Derivative [Line Items] |  |  |
Net gain/(loss) recognized in income | $ (27) | $ (68) | $ (15)
Unrealized Gains Losses On Insured Derivatives [Member] | Credit Default Swap [Member] |  |  |
Derivative [Line Items] |  |  |
Net gain/(loss) recognized in income | 31 | 0 | 21
Realized Gains Losses And Other Settlements On Insured Derivatives [Member] | Credit Default Swap [Member] |  |  |
Derivative [Line Items] |  |  |
Net gain/(loss) recognized in income | (56) | (51) | (40)
Foreign Exchange And Other Derivative Financial Instruments [Member] | Interest Rate Swap [Member] |  |  |
Derivative [Line Items] |  |  |
Net gain/(loss) recognized in income | 4 | 3 | (11)
Foreign Exchange And Other Derivative Financial Instruments [Member] | All Other [Member] |  |  |
Derivative [Line Items] |  |  |
Net gain/(loss) recognized in income | (4) | (19) | (2)
Foreign Exchange And Other Derivative Financial Instruments Attributable To V I E [Member] | Interest Rate Swaps V I E [Member] |  |  |
Derivative [Line Items] |  |  |
Net gain/(loss) recognized in income | 0 | 0 | 8
Foreign Exchange And Other Derivative Financial Instruments Attributable To V I E [Member] | Currency Swaps Vie [Member] |  |  |
Derivative [Line Items] |  |  |
Net gain/(loss) recognized in income | $ (2) | $ (1) | $ 9

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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959 + 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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