v3.26.1
Financial instruments and fair value measurements - Schedule of gross amounts and fair values of debt instruments (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Estimated Fair Value Of Financial Instruments [Line Items]    
Gross amount $ 3,715.4 $ 3,967.9
Fair value 3,670.1 3,910.1
Senior secured credit facilities: | Euro term loans B-6 | Euro    
Estimated Fair Value Of Financial Instruments [Line Items]    
Gross amount 427.1 645.2
Fair value 429.5 652.0
Senior secured credit facilities: | Euro term loans A-1 | Euro    
Estimated Fair Value Of Financial Instruments [Line Items]    
Gross amount 450.9 469.2
Fair value 453.2 445.5
Notes | 3.875% unsecured notes    
Estimated Fair Value Of Financial Instruments [Line Items]    
Gross amount 800.0 800.0
Fair value 764.0 765.9
Notes | 3.875% Euro unsecured notes    
Estimated Fair Value Of Financial Instruments [Line Items]    
Gross amount 456.6 469.2
Fair value 457.6 470.2
Notes | 4.625% unsecured notes    
Estimated Fair Value Of Financial Instruments [Line Items]    
Gross amount 1,550.0 1,550.0
Fair value 1,535.0 1,542.2
Finance lease liabilities    
Estimated Fair Value Of Financial Instruments [Line Items]    
Gross amount 25.6 26.9
Fair value 25.6 26.9
Other Debt    
Estimated Fair Value Of Financial Instruments [Line Items]    
Gross amount 5.2 7.4
Fair value $ 5.2 $ 7.4