v3.26.1
Share-based Compensation - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended
Jan. 27, 2026
Mar. 31, 2026
Mar. 31, 2025
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Share-Based Payment Arrangement, Expense   $ 42 $ 37
Shares issued   212,000  
Issuance of shares under employee stock compensation plans (in shares)   13,000  
Net total number of shares   5,000  
Newfront Insurance Holdings, Inc      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Acquisition of Newfront (in shares)   199,028  
Restricted Stock Units [Member]      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vested (shares)   73,000  
Restricted Stock Units [Member] | Newfront Insurance Holdings, Inc      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Number of shares, granted 187,000 187,000  
Restricted Stock Units [Member] | Not Issued [Member]      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Vested (shares)   68,000  
Restricted Stock Awards [Member] | Newfront Insurance Holdings, Inc      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Shares issued under ESPP 199,000    
Number of shares, granted 225,000 225,000  
Employee Share Purchase Plan [Member]      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Shares issued under ESPP   8,000  
Transaction and Integration Expense [Member]      
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Share-Based Payment Arrangement, Expense   $ 9 $ 0