Claim and Claim Adjustment Expense Reserves (International - Net prior year claim and allocated claim adjustment expense reserve development) (Details) - International - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Liability for Claims and Claims Adjustment Expense [Line Items] | ||
| Commercial | $ 0 | $ 0 |
| Specialty | 0 | 0 |
| Other | 0 | 0 |
| Total pretax (favorable) unfavorable development | $ 0 | $ 0 |