v3.26.1
Property Casualty Loss and Loss Expenses - Consolidated Property Casualty Loss and Loss Expense Reserves (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Summary of Consolidated Property Casualty Loss and Loss Expense Reserves [Roll Forward]        
Gross loss and loss expense reserves, beginning of period     $ 11,507  
Prior accident years $ (42) $ (63) (123) $ (154)
Gross loss and loss expense reserves, end of period 12,479   12,479  
Property and Casualty Insurance        
Summary of Consolidated Property Casualty Loss and Loss Expense Reserves [Roll Forward]        
Gross loss and loss expense reserves, beginning of period 11,884 10,707 11,450 9,937
Less reinsurance recoverable 406 551 438 269
Net loss and loss expense reserves, beginning of period 11,478 10,156 11,012 9,668
Current accident year 1,850 1,650 3,598 3,628
Prior accident years (42) (63) (123) (154)
Total incurred 1,808 1,587 3,475 3,474
Current accident year 612 591 846 1,184
Prior accident years 681 655 1,648 1,461
Total paid 1,293 1,246 2,494 2,645
Net loss and loss expense reserves, end of period 11,993 10,497 11,993 10,497
Plus reinsurance recoverable 413 504 413 504
Gross loss and loss expense reserves, end of period $ 12,406 $ 11,001 $ 12,406 $ 11,001