Claim and Claim Adjustment Expense Reserves - Net Prior Year Loss Reserve Development in Property and Casualty Operations (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Surety | ||
| Net Prior Year Development [Abstract] | ||
| Total pretax (favorable) unfavorable development | $ (18) | |
| Warranty | ||
| Net Prior Year Development [Abstract] | ||
| Total pretax (favorable) unfavorable development | 10 | 13 |
| Commercial auto | ||
| Net Prior Year Development [Abstract] | ||
| Total pretax (favorable) unfavorable development | 50 | |
| Workers’ compensation | ||
| Net Prior Year Development [Abstract] | ||
| Total pretax (favorable) unfavorable development | 1 | (2) |
| Other insurance operations | ||
| Net Prior Year Development [Abstract] | ||
| Total pretax (favorable) unfavorable development | $ 22 | $ 0 |