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Loss and Loss Adjustment Expense Reserves (Schedule of Losses and Loss Adjustment Expenses Reserves and Recoveries) (Detail) - USD ($) $ in Millions | Sep. 30, 2023 | Dec. 31, 2022
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Loss And Lae Reserves [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Loss and loss adjustment expense reserves | [1] | $ 450 | $ 439
Insurance Loss Recoverable [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Insurance Loss Recoverable |  | 177 | 137
Non Variable Interest Entity [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Insurance Loss Recoverable |  | 177 | 137
Loss and loss adjustment expense reserves |  | 450 | 439
US Public Finance Insurance [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Insurance Loss Recoverable |  | 150 | 107
Loss and loss adjustment expense reserves | [1] | 228 | 154
International And Structured Finance Insurance [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Insurance Loss Recoverable |  | 28 | 32
Loss and loss adjustment expense reserves | [1] | 314 | 488
International And Structured Finance Insurance [Member] | Non Variable Interest Entity [Member] |  |  |
Loss And Loss Adjustment Expense Reserves [Line Items] |  |  |
Insurance Loss Recoverable |  | 27 | 30
Loss and loss adjustment expense reserves | [1] | 222 | 285
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 |  | (1) | (2)
Loss and loss adjustment expense reserves | [1] | $ (92) | $ (203)
[1] | Amounts are net of estimated recoveries of expected future claims.

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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 -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (cc) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480081/944-40-50-3 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480081/944-40-50-3 + 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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- Details
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- Details
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