Stock Based Compensation Expense (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stock-based Payment Award
Stock-based compensation expense		$ 84.8	$ 71.1	$ 82.7
Tax benefit		18.0	17.3	20.0
Stock-settled awards
Stock-based Payment Award
Stock-based compensation expense		36.7	38.4	33.5
Cash-settled awards
Stock-based Payment Award
Stock-based compensation expense		1.3	1.0	0.8
Performance-based awards
Stock-based Payment Award
Stock-based compensation expense		33.4	28.6	46.7
Employee stock purchase plan
Stock-based Payment Award
Stock-based compensation expense		2.1	1.4	1.1
Other
Stock-based Payment Award
Stock-based compensation expense	[1]	$ 11.3	$ 1.7	$ 0.6

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