v3.26.3
Reserve for Unpaid Losses and Loss Adjustment Expenses - EB Liabilities for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]        
Beginning liabilities for unpaid losses and loss adjustment expenses, gross $ 46,268      
Ending liabilities for unpaid losses and loss adjustment expenses, gross 47,714      
Group Insurance Policy [Member]        
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]        
Beginning liabilities for unpaid losses and loss adjustment expenses, gross 8,113 $ 8,206    
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments (306) (281) $ (282) $ (282)
Ending liabilities for unpaid losses and loss adjustment expenses, gross 7,959 7,800 $ 7,831 $ 7,924
Ending liabilities for unpaid losses and loss adjustment expenses, gross 8,265 8,081    
Provision for unpaid losses and loss adjustment expense        
Current incurral year 4,096 3,949    
Prior year's discount accretion 162 153    
Prior incurral year development [1] (339) (486)    
Total provision for unpaid losses and loss adjustment expenses 3,919 3,616    
Less: payments        
Current incurral year (1,996) (1,899)    
Prior incurral years (1,795) (1,841)    
Total payments (3,791) (3,740)    
Group Insurance Policy [Member] | Insurance Operating Costs and Other Expenses [Member]        
Provision for unpaid losses and loss adjustment expense        
Total provision for unpaid losses and loss adjustment expenses $ 138 $ 129