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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
--- | --- | ---
Mar. 31, 2025 | Dec. 31, 2024
Credit Derivatives |  |
Estimated remaining weighted average life of credit derivatives (in years) | 9 years 1 month 6 days | 8 years 4 months 24 days
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | $ 3,761 | $ 4,212
Net Fair Value Asset (Liability) | (30) | (29)
Public finance | United States |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 1,021 | 1,025
Net Fair Value Asset (Liability) | (12) | (12)
Public finance | Non United States |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 1,627 | 2,044
Net Fair Value Asset (Liability) | (16) | (15)
Structured finance | United States |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 148 | 150
Net Fair Value Asset (Liability) | (2) | (2)
Structured finance | Non United States |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 965 | 993
Net Fair Value Asset (Liability) | $ 0 | $ 0

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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 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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