v3.26.1
Stockholders' equity - Schedule of Changes in Accumulated Other Comprehensive Loss (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Stockholders' equity    
Balance at beginning of period $ 751.1 $ 817.0
Balance at end of period 745.0 847.0
Currency translation    
Stockholders' equity    
Balance at beginning of period (267.3) (300.0)
Other comprehensive income 4.2 17.3
Balance at end of period (263.1) (282.7)
Accumulated Defined benefit pension plans | Defined benefit pension plans    
Stockholders' equity    
Balance at beginning of period (29.0) (63.8)
Other comprehensive income 0.3 0.4
Balance at end of period (28.7) (63.4)
Accumulated Defined benefit pension plans | OPEB Plans    
Stockholders' equity    
Balance at beginning of period 0.7 0.3
Total Accumulated Other Comprehensive Loss    
Stockholders' equity    
Balance at beginning of period (295.6) (363.5)
Other comprehensive income 4.5 17.7
Balance at end of period $ (291.1) $ (345.8)