Special Charges and Other, Net - Summary of Activity in Special Charges and Other, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Restructuring
Employee separation costs	$ (1.3)	$ 6.0	$ 65.3
Gain on sale of assets	(5.8)	(1.5)	0.0
Impairment charges	0.0	0.7	3.6
Contract exit costs	(1.6)	5.2	(4.7)
Wafer fabrication restructuring	15.0	18.0	0.0
Other	0.1	2.6	(0.3)
Legal contingencies	0.2	15.7	(30.2)
Contingent consideration revaluation	(4.9)	0.0	0.0
Total	$ 1.7	$ 46.7	$ 33.7