v3.26.3
Claim and Claim Adjustment Expense Reserves - Reconciliation of Claim and Claim Adjustment Expense Reserves (Details) - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]    
Gross reserves, beginning of year $ 26,599 $ 24,976
Ceded reserves, beginning of year 5,982 5,713
Net reserves, beginning of year 20,617 19,263
Net incurred claim and claim adjustment expenses:    
Provision for insured events of current year 5,366 5,011
Increase (decrease) in provision for insured events of prior years 189 191
Amortization of discount 28 29
Total net incurred 5,583 5,231
Net payments attributable to:    
Current year events (691) (659)
Prior year events (3,551) (3,463)
Total net payments (4,242) (4,122)
Foreign currency translation adjustment and other (106) 165
Net reserves, end of period 21,852 20,537
Ceded reserves, end of period 6,065 5,988
Gross reserves, end of period $ 27,917 $ 26,525