Special Charges and Other, Net - Summary of Activity in Special Charges and Other, Net (Details) - USD ($) $ in Millions		12 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Restructuring
Employee separation costs		$ 6.0	$ 65.3	$ 1.2
Gain on sale of assets		(1.5)	0.0	(4.4)
Impairment charges		3.2	3.6	0.0
Contract exit costs		13.4	(4.7)	0.7
Other		9.9	(0.3)	0.0
Legal contingencies		15.7	(30.2)	0.0
Non-restructuring contract exit costs and other		0.0	0.0	20.0
Total	[1]	$ 46.7	$ 33.7	$ 17.5

[1] Year ended March 31,(1) Includes share-based compensation expense as follows: Cost of sales$20.9 $14.9 $13.8Research and development$82.9 $72.0 $42.5Selling, general and administrative$66.4 $62.3 $36.9Special charges and other, net$— $17.2 $—