Share-Based Payments - Compensation Expense (Details) - Options, RSUs, DSUs and PSUs Awards - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax share-based compensation expense	$ 44.9	$ 33.6	$ 32.1
Tax benefit	(7.8)	(5.9)	(5.5)
After-tax share-based compensation expense	$ 37.1	$ 27.7	$ 26.6