Special Charges (Income) and Other, Net - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring cost incurred	$ 11.7
Restructuring and related costs, expected certain water fabrication	10.0		$ 10.0
Employee separation costs	3.4	$ 3.3	10.7	$ 60.5
Contract exit costs (income)	10.3	0.1	10.8	(2.9)
Restructuring reserve	40.0		40.0		$ 47.8
Employee Separation
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	14.6		14.6		$ 12.9
Employee Separation | Semiconductor products
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, costs incurred to date	116.3		116.3
Employee separation costs	3.4	$ 3.3	10.7	$ 60.5
Contract Termination | Semiconductor products
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, costs incurred to date	$ 50.9		$ 50.9