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Loss And Loss Adjustment Expense Reserves (Schedule Of Losses And Loss Adjustment Expenses Reserves and Recoveries) (Detail) - USD ($) $ in Millions | Mar. 31, 2021 | Dec. 31, 2020
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Loss And Lae Reserves [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Loss and loss adjustment expense reserves | [1],[2] | $ 990 | $ 990
Insurance Loss Recoverable [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Insurance Loss Recoverable |  | 1,622 | 1,677
Non Variable Interest Entity [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Insurance Loss Recoverable |  | 1,622 | 1,677
Loss and loss adjustment expense reserves |  | 990 | 990
US Public Finance [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Insurance Loss Recoverable |  | 1,216 | 1,220
Loss and loss adjustment expense reserves | [1] | 524 | 469
International And Structured Finance Insurance [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Insurance Loss Recoverable | [3] | 426 | 1,082
Loss and loss adjustment expense reserves | [1],[3] | 705 | 780
International And Structured Finance Insurance [Member] | Non Variable Interest Entity [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Insurance Loss Recoverable |  | 406 | 457
Loss and loss adjustment expense reserves | [1] | 466 | 521
Consolidation Elimination [Member] | International And Structured Finance Insurance [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Insurance Loss Recoverable | [3] | (20) | (625)
Loss and loss adjustment expense reserves | [1],[3] | $ (239) | $ (259)
[1] | Amounts are net of expected recoveries.
[2] | Includes changes in amount and timing of estimated payments and recoveries.
[3] | Includes loan repurchase commitments of $604 million as of December 31, 2020.

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- Definition Carrying amount as of the balance sheet date of paid insurance policy claims and LAE expense expected to be recovered. + References No definition available. + Details
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- Definition Loss And Loss Adjustment Expense Reserves [Line Items] + References No definition available. + Details
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- Definition The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (cc) -URI http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437 + Details
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Period Type: | instant

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- Details
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- Details
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- Details
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- Details
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- Details
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