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Derivative Instruments (Effect Of Derivative Instruments On Consolidated Statements Of Operations) (Detail) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018
Derivative [Line Items] |  |  |  |
Net gain/(loss) recognized in income | $ (46) | $ 0 | $ (56) | $ 8
Unrealized Gains Losses On Insured Derivatives [Member] | Credit Default Swap [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Net gain/(loss) recognized in income | 1 | 18 | 14 | 32
Realized Gains Losses And Other Settlements On Insured Derivatives [Member] | Credit Default Swap [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Net gain/(loss) recognized in income | (1) | (25) | (1) | (44)
Net gains (losses) on financial instruments at fair value and foreign exchange [Member | Interest Rate Swap [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Net gain/(loss) recognized in income | (35) | 7 | (55) | 25
Net gains (losses) on financial instruments at fair value and foreign exchange [Member | All Other [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Net gain/(loss) recognized in income | (9) | 0 | (9) | 0
Net gains (losses) on financial instruments at fair value and foreign exchange-VIE [Member] | Currency Swaps Vie [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Net gain/(loss) recognized in income | $ (2) | $ 0 | $ (5) | $ (5)

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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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