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Outstanding Exposure - Schedule of Non-Financial Guaranty Exposure (Details) - USD ($) $ in Billions | Dec. 31, 2027 | Mar. 31, 2026 | Dec. 31, 2025
--- | --- | --- | ---
Diversified real estate |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Gross Exposure |  | $ 2.0 | $ 2.0
Net Exposure |  | 2.0 | 2.0
Insurance reserve financing and securitizations |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Gross Exposure |  | 1.5 | 1.5
Net Exposure |  | 1.2 | 1.2
Insurance reserve financing and securitizations | Forecast |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Gross Exposure | $ 1.6 |  |
Net Exposure | $ 1.3 |  |
Pooled corporate obligations |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Gross Exposure |  | 0.7 | 0.9
Net Exposure |  | 0.7 | 0.9
Aircraft residual value insurance (RVI) |  |  |
Schedule of Insured Financial Obligations [Line Items] |  |  |
Gross Exposure |  | 0.2 | 0.2
Net Exposure |  | $ 0.1 | $ 0.1

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