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Outstanding Exposure - Schedule of Non-Financial Guaranty Exposure (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Diversified real estate
Schedule of Insured Financial Obligations [Line Items]
Gross Exposure	$ 2,071	$ 2,004
Net Exposure	2,071	2,004
Insurance reserve financings and securitizations
Schedule of Insured Financial Obligations [Line Items]
Gross Exposure	1,502	1,449
Net Exposure	1,179	1,126
Pooled corporate obligations
Schedule of Insured Financial Obligations [Line Items]
Gross Exposure	840	868
Net Exposure	840	868
Aircraft residual value insurance
Schedule of Insured Financial Obligations [Line Items]
Gross Exposure	147	147
Net Exposure	$ 87	$ 87

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Specialty Business, Gross Par

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