v3.25.2
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, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Summary of Consolidated Property Casualty Loss and Loss Expense Reserves [Roll Forward]        
Gross loss and loss expense reserves, beginning of period     $ 10,003  
Prior accident years $ (63) $ (40) (154) $ (140)
Gross loss and loss expense reserves, end of period 11,072   11,072  
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 10,707 9,178 9,937 8,975
Less reinsurance recoverable 551 332 269 362
Net loss and loss expense reserves, beginning of period 10,156 8,846 9,668 8,613
Current accident year 1,650 1,452 3,628 2,822
Prior accident years (63) (40) (154) (140)
Total incurred 1,587 1,412 3,474 2,682
Current accident year 591 483 1,184 688
Prior accident years 655 584 1,461 1,416
Total paid 1,246 1,067 2,645 2,104
Net loss and loss expense reserves, end of period 10,497 9,191 10,497 9,191
Plus reinsurance recoverable 504 303 504 303
Gross loss and loss expense reserves, end of period $ 11,001 $ 9,494 $ 11,001 $ 9,494