Leases - Schedule of Operating Expense and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Mar. 31, 2019
Leases [Abstract]
Operating lease expense	$ 12.2	$ 36.7
Variable lease expense	2.6	8.1
Short-term lease expense	2.5	7.3
Total lease expense	17.3	52.1
Other assets:
Right-of-use assets	135.7	135.7
Accrued liabilities:
Current portion of lease liabilities	42.9	42.9	$ 0.0
Other long-term liabilities:
Non-current portion of lease liabilities	111.0	111.0
Total lease liabilities	$ 153.9	$ 153.9
Weighted average remaining lease-term (in years)	4 years 6 months	4 years 6 months
Weighted average discount rate	4.60%	4.60%