Contracts Accounted for as Insurance - Selected Information for Policies Paid In Installments (Details) - USD ($) $ in Millions |
6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Dec. 31, 2024 |
Jun. 30, 2024 |
Dec. 31, 2023 |
|
| Financial Guarantee Insurance Premiums [Line Items] | ||||
| Premiums receivable, net of commissions payable | $ 1,631 | $ 1,551 | $ 1,472 | $ 1,468 |
| Financial Guarantee Policies Paid in Installments | ||||
| Financial Guarantee Insurance Premiums [Line Items] | ||||
| Premiums receivable, net of commissions payable | 1,630 | 1,550 | ||
| Deferred premium revenue | $ 1,870 | $ 1,901 | ||
| Weighted-average risk-free rate used to discount premiums | 2.50% | 2.50% | ||
| Weighted-average period of premiums receivable (in years) | 12 years 1 month 6 days | 12 years 3 months 18 days |