The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.

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Liability for Policy and Contract Claims - Schedule of Liability for Policy and Contract Claims (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025	Dec. 31, 2024
Liability for Claims and Claims Adjustment Expense [Line Items]
Total liability for policy and contract claims	$ 743	$ 727	$ 698	$ 670
Other mortgage insurance business
Liability for Claims and Claims Adjustment Expense [Line Items]
Total liability for policy and contract claims	7	6
Enact segment
Liability for Claims and Claims Adjustment Expense [Line Items]
Total liability for policy and contract claims	590	572
Closed Block segment
Liability for Claims and Claims Adjustment Expense [Line Items]
Total liability for policy and contract claims	$ 146	$ 149