Share-Based Compensation - Allocation of Compensation Expense (Benefit) by Plan (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-Based Compensation
Total share-based compensation expense (benefit) before tax	$ 25.6	$ (12.4)
Stock options
Share-Based Compensation
Total share-based compensation expense (benefit) before tax	5.7	4.9
RSUs
Share-Based Compensation
Total share-based compensation expense (benefit) before tax	15.5	12.2
STAP awards
Share-Based Compensation
Total share-based compensation expense (benefit) before tax	3.9	(30.0)
ESPP
Share-Based Compensation
Total share-based compensation expense (benefit) before tax	$ 0.5	$ 0.5