Stock Based Compensation Expense (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Stock-based Payment Award
Stock-based compensation expense		$ 52.9	$ 55.7	$ 84.8
Tax benefit		12.5	13.1	18.0
Stock-settled awards
Stock-based Payment Award
Stock-based compensation expense		27.8	26.3	36.7
Cash-settled awards
Stock-based Payment Award
Stock-based compensation expense		0.3	0.3	1.0
Performance-based awards
Stock-based Payment Award
Stock-based compensation expense		18.9	23.7	33.4
Employee stock purchase plan
Stock-based Payment Award
Stock-based compensation expense		2.9	3.1	2.1
Other
Stock-based Payment Award
Stock-based compensation expense	[1]	2.7	2.0	11.3
Equity Option
Stock-based Payment Award
Stock-based compensation expense		$ 0.3	$ 0.3	$ 0.3

[1] Represents charges recorded for severance expense related to stock-based compensation awards.