Share Plans - Share-based compensation expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	$ 37.0	$ 39.7	$ 29.1
Equity Option
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	4.7	5.3	4.3
Restricted Stock Units
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	14.7	16.1	15.0
Performance Shares
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	$ 17.6	$ 18.3	$ 9.8