Business Acquisitions - Narrative, Microsemi (Details) - USD ($) $ in Millions		12 Months Ended
	May 29, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2018
Business Acquisition [Line Items]
Acquisition of Microsemi, net of cash acquired		$ 7,850.6	$ 0.0	$ 0.0
Net sales		5,349.5	3,980.8	3,407.8
Net Income (Loss)		355.9	$ 255.4	$ 164.6
Microsemi Corporation
Business Acquisition [Line Items]
Cash paid for shares	$ 8,190.0
Non cash consideration of certain share-based payment awards	53.9
Total consideration transferred	8,240.0
Liabilities assumed	3,230.0	3,232.6			$ 3,183.3
Payments to acquire businesses portion funded by additional line of credit borrowings	8,100.0
Transaction and other fees incurred in transaction	$ 22.0
Useful life (in years)	13 years
Deferred tax liabilities	$ 856.7
Net sales		1,568.6
Net Income (Loss)		$ (570.8)
Revolving Credit Facility | Microsemi Corporation
Business Acquisition [Line Items]
Payments to acquire businesses portion funded by additional line of credit borrowings	3,100.0
Term Loan Facility | Microsemi Corporation
Business Acquisition [Line Items]
Payments to acquire businesses portion funded by additional line of credit borrowings	3,000.0
Senior Secured Notes | Microsemi Corporation
Business Acquisition [Line Items]
Payments to acquire businesses portion funded by additional line of credit borrowings	$ 2,000.0
Backlog | Microsemi Corporation
Business Acquisition [Line Items]
Useful life (in years)	1 year	1 year
Other Liabilities | Microsemi Corporation
Business Acquisition [Line Items]
Acquisition of Microsemi, net of cash acquired	$ 2,060.0