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Contracts Accounted for as Credit Derivatives - Credit Derivatives Subordination and Ratings (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
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Mar. 31, 2024 | Dec. 31, 2023
Credit Derivatives |  |
Estimated remaining weighted average life of credit derivatives (in years) | 10 years 10 months 24 days | 11 years 1 month 6 days
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | $ 3,421 | $ 3,608
Net Fair Value Asset (Liability) | (39) | (50)
Expected loss to be recovered | 1 | 2
Public finance | United States |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 1,077 | 1,149
Net Fair Value Asset (Liability) | (14) | (15)
Public finance | Non United States |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 1,507 | 1,522
Net Fair Value Asset (Liability) | (19) | (20)
Structured finance | United States |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 223 | 322
Net Fair Value Asset (Liability) | (5) | (13)
Structured finance | Non United States |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 614 | 615
Net Fair Value Asset (Liability) | $ (1) | $ (2)

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- Definition Expected Loss on Credit Derivative to Be Paid (Recovered), Including Representation and Warranty Liability (Benefit) + References No definition available. + Details
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Balance Type: | credit
Period Type: | instant

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- References No definition available. + Details
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- Definition Represents the outstanding principal amounts of the underlying insured obligations that are accounted for as credit derivatives, net of protection purchased. + References No definition available. + Details
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- Definition Average period covered by credit risk derivative contracts, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 4K -Subparagraph (a)(1) -SubTopic 10 -Topic 815 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4K + 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 Fair value of credit risk derivative asset after deduction of credit risk derivative liability. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 4K -Subparagraph (c) -SubTopic 10 -Topic 815 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4K + Details
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