Special (Income) Charges and Other, Net - Restructuring (Details) $ in Millions	9 Months Ended
	Dec. 31, 2018 USD ($)
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	$ 47.2
Charges/income	41.2
Payments	(55.9)
Non-cash - Other	1.0
Restructuring reserve, ending balance	51.5
Current	29.1
Non-current	22.4
Employee Separation Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	0.8
Charges/income	44.1
Payments	(42.8)
Non-cash - Other	0.0
Restructuring reserve, ending balance	13.5
Exit Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	27.3
Charges/income	(2.9)
Payments	(9.7)
Non-cash - Other	0.4
Restructuring reserve, ending balance	21.7
Non-Restructuring, Exit Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	19.1
Charges/income	0.0
Payments	(3.4)
Non-cash - Other	0.6
Restructuring reserve, ending balance	16.3
Microsemi Corporation
Restructuring Reserve [Roll Forward]
Additions due to Microsemi acquisition	18.0
Microsemi Corporation | Employee Separation Costs
Restructuring Reserve [Roll Forward]
Additions due to Microsemi acquisition	11.4
Microsemi Corporation | Exit Costs
Restructuring Reserve [Roll Forward]
Additions due to Microsemi acquisition	6.6
Microsemi Corporation | Non-Restructuring, Exit Costs
Restructuring Reserve [Roll Forward]
Additions due to Microsemi acquisition	$ 0.0