v3.25.4
Total Equity - Common stock - narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Jan. 01, 2026
Dec. 31, 2025
Dec. 31, 2024
Total Equity      
Reduction of issued capital purchases for cancellation   $ 2,501.7 $ 1,815.7
Subordinate voting shares      
Total Equity      
Purchases for cancellation (in shares)   1,006,535 1,346,953
Cost of shares purchased for cancellation   $ 1,625.2 $ 1,588.4
Treasury shares acquired (in shares)   117,918 207,974
Value of treasury shares purchased   $ 189.1 $ 240.4
Treasury shares reissued (in shares)   312,073 220,145
Treasury shares reissued cost   $ 122.9 $ 108.3
Award vesting period   5 years 5 years
Compensation expense   $ 176.6 $ 164.9
Subordinate voting shares | Cancellation of treasury share transactions      
Total Equity      
Purchases for cancellation (in shares) 226,694    
Cost of shares purchased for cancellation $ 384.0    
Subordinate voting shares | Prem Watsa      
Total Equity      
Purchases for cancellation (in shares)     275,000
Cost of shares purchased for cancellation     $ 304.3
Retained earnings      
Total Equity      
Reduction of issued capital purchases for cancellation   $ 1,375.9 $ 1,254.7