v3.25.4
Accumulated other comprehensive income (loss) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Changes in AOCI      
Beginning balance $ 5,956.7 $ 5,252.6 $ 4,855.4
Change due to income taxes 15.8 (4.4) 16.3
Ending balance 5,565.0 5,956.7 5,252.6
AOCI      
Changes in AOCI      
Beginning balance (184.0) (69.0) (100.3)
Unrealized gain (loss) 143.5 (82.5) 51.9
Reclassification of loss (gain) into earnings 7.8 (28.1) (36.9)
Change due to income taxes 15.8 (4.4) 16.3
Ending balance (16.9) (184.0) (69.0)
Foreign currency translation      
Changes in AOCI      
Beginning balance (177.4) (82.8) (131.3)
Unrealized gain (loss) 123.2 (83.3) 38.3
Reclassification of loss (gain) into earnings 0.0 (0.5) 0.0
Change due to income taxes 23.2 (10.8) 10.2
Ending balance (31.0) (177.4) (82.8)
Derivative instruments      
Changes in AOCI      
Beginning balance 0.2 12.6 19.9
Unrealized gain (loss) 9.3 18.2 21.3
Reclassification of loss (gain) into earnings (9.5) (34.5) (31.0)
Change due to income taxes 0.0 3.9 2.4
Ending balance 0.0 0.2 12.6
Defined benefit plans      
Changes in AOCI      
Beginning balance (6.8) 1.2 11.1
Unrealized gain (loss) 11.0 (17.4) (7.7)
Reclassification of loss (gain) into earnings 17.3 6.9 (5.9)
Change due to income taxes (7.4) 2.5 3.7
Ending balance $ 14.1 $ (6.8) $ 1.2