v3.26.3
Unpaid losses and loss expenses (RF) (Details) - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Liability for Claims and Claims Adjustment Expense [Line Items]    
Gross unpaid losses and loss expenses – beginning of period $ 88,018 $ 84,004
Reinsurance recoverable on unpaid losses and loss expenses - beginning of period [1] 18,346 17,734
Net unpaid losses and loss expenses – beginning of period 69,672 66,270
Current Year Claims and Claims Adjustment Expense 21,470 21,342
Prior Year Claims and Claims Adjustment Expense [2] (1,122) (923)
Total, Incurred 20,348 20,419
Net loss and loss expenses paid, Current Year 6,172 5,551
Net loss and loss expenses paid, Prior Years 11,233 12,135
Total, Paid 17,405 17,686
Foreign currency revaluation and other 295 1,015
Net unpaid losses and loss expenses – end of period 72,910 70,018
Reinsurance recoverable on unpaid losses and loss expenses - end of period [1] (18,919) (18,421)
Gross unpaid losses and loss expenses – end of period 91,829 88,439
prior period development, net adjustments $ 42 $ 58
[1] Net of valuation allowance for uncollectible reinsurance.
[2] Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments, earned premiums, and A&H long-duration lines totaling $42 million and $58 million for the nine months ended September 30, 2026 and 2025, respectively.