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Derivatives - Credit Derivatives Subordination and Ratings (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2026 | Dec. 31, 2025
Credit Derivatives |  |
Estimated remaining weighted average life of credit derivatives (in years) | 9 years 3 months 18 days | 8 years 7 months 6 days
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | $ 3,300 | $ 3,800
Net Fair Value Asset (Liability) | (16) | (15)
Public finance | United States |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 1,000 | 1,000
Net Fair Value Asset (Liability) | (2) | (2)
Public finance | Non-U.S. public finance |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 1,300 | 1,600
Net Fair Value Asset (Liability) | (13) | (12)
Structured finance | United States |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 100 | 200
Net Fair Value Asset (Liability) | (1) | (1)
Structured finance | Non-U.S. public finance |  |
Net Par Outstanding on Credit Derivatives |  |
Net Par Outstanding | 900 | 1,000
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://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4K -Subparagraph (a)(1) -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://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4K -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-4K + Details
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