Comprehensive Income - Components of AOCL (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Components of Accumulated other comprehensive income, net of taxes
Beginning balance	$ 3,157.9	$ 3,341.9	$ 3,317.3	$ 3,499.1
Other comprehensive income before reclassifications			12.1
Amounts reclassified			(1.4)
Other comprehensive income (loss), net of tax	(21.6)	24.9	10.7	(53.5)
Ending balance	3,199.5	3,328.4	3,199.5	3,328.4
Total
Components of Accumulated other comprehensive income, net of taxes
Beginning balance			(162.2)
Ending balance	(151.5)		(151.5)
Foreign Currency Translation Adjustment
Components of Accumulated other comprehensive income, net of taxes
Beginning balance			(161.9)
Other comprehensive income before reclassifications			11.7
Amounts reclassified			0.0
Other comprehensive income (loss), net of tax	(19.7)	24.7	11.7	(51.4)
Ending balance	(150.2)		(150.2)
Realized and Unrealized Gains (Losses) on Derivative Financial Instruments
Components of Accumulated other comprehensive income, net of taxes
Beginning balance			(0.3)
Other comprehensive income before reclassifications			0.4
Amounts reclassified			(1.4)
Other comprehensive income (loss), net of tax	(1.9)	$ 0.2	(1.0)	$ (2.1)
Ending balance	$ (1.3)		$ (1.3)