Accumulated Other Comprehensive Loss - Schedule of Changes in the Components of AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Changes in the components of AOCI
Beginning balance	$ 5,585.5	$ 5,287.5
Other comprehensive income (loss) before reclassifications	0.2
Amounts reclassified from accumulated other comprehensive income (loss)	0.3
Other comprehensive income (loss), net of tax effect	0.5	(0.3)
Ending balance	5,501.3	5,288.3
Total
Changes in the components of AOCI
Beginning balance	(21.6)	(20.7)
Other comprehensive income (loss), net of tax effect	0.5	(0.3)
Ending balance	(21.1)	$ (22.3)
Minimum Pension Liability
Changes in the components of AOCI
Beginning balance	(5.1)
Other comprehensive income (loss) before reclassifications	(0.8)
Amounts reclassified from accumulated other comprehensive income (loss)	0.3
Other comprehensive income (loss), net of tax effect	(0.5)
Ending balance	(5.6)
Foreign Currency
Changes in the components of AOCI
Beginning balance	(16.5)
Other comprehensive income (loss) before reclassifications	1.0
Amounts reclassified from accumulated other comprehensive income (loss)	0.0
Other comprehensive income (loss), net of tax effect	1.0
Ending balance	$ (15.5)