v3.25.3
Goodwill and Other Intangible Assets (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Goodwill by segment    
Goodwill $ 4,271 $ 4,233
Reportable Segments [Member] | Business Insurance [Member]    
Goodwill by segment    
Goodwill 2,601 2,572
Reportable Segments [Member] | Bond & Specialty Insurance [Member]    
Goodwill by segment    
Goodwill 838 834
Reportable Segments [Member] | Personal Insurance [Member]    
Goodwill by segment    
Goodwill 806 801
Other [Member]    
Goodwill by segment    
Goodwill $ 26 $ 26