v3.25.1
Losses and Loss Adjustment Expenses - Reconciliation of Beginning and Ending Reserves for Losses and Loss Adjustment Expenses (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Dec. 31, 2024
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]      
Balance as of beginning of period $ 11,404 $ 12,359  
Reinsurance reserves recoverable on unpaid losses (628) (774)  
Net balance as of beginning of period 10,776 11,585  
Current period:      
Increase in estimates of net ultimate losses 3 5  
Total current period 3 5  
Prior periods:      
Reduction in estimates of net ultimate losses (8) (6)  
Reduction in provisions for ULAE (21) (17)  
Amortization of fair value adjustments 5 3  
Changes in fair value - fair value option 5 (4)  
Total prior periods (19) (24)  
Total net incurred losses and loss adjustment expenses [1] (16) (19)  
Net paid losses:      
Prior periods (739) (670)  
Total net paid losses (739) (670)  
Other changes:      
Effect of exchange rate movement 66 (69)  
Assumed business 358 0  
Total other changes 424 (69)  
Net balance as of March 31 10,445 10,827  
Reinsurance reserves recoverable on unpaid losses 636 723  
Balance as of March 31 11,081 11,550  
Reconciliation to Consolidated Balance Sheets:      
Losses and loss adjustment expenses [1] 10,085   $ 10,407
Losses and loss adjustment expenses, at fair value 996   997
Total losses and loss adjustment expenses 11,081 11,550 11,404
Reinsurance balances recoverable on paid and unpaid losses 522   533
Reinsurance balances recoverable on paid and unpaid losses - fair value option 194   179
Total reinsurance balances recoverable on paid and unpaid losses 716   712
Less: Paid losses recoverable (80)   (84)
Reinsurance reserves recoverable on unpaid losses $ 636 $ 723 $ 628
[1] See Note 17 for additional information regarding related party transactions.