Intangible Assets, by Major Class (Details) - USD ($) $ in Millions		3 Months Ended
	May 29, 2018	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2018
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		$ 7,403.8		$ 2,683.1
Accumulated Amortization		(1,154.9)		(1,021.1)
Net Amount		6,248.9		1,662.0
In-process technology reaching technological feasibility and reclassified		1.0
Amortization of Intangible Assets		134.8	$ 122.8
Impairment of Intangible Assets		2.0	0.1
Projected Amortization Expense
2019		855.5
2020		1,045.1
2021		983.7
2022		704.3
2023		612.1
Core and developed technology
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		5,754.9		1,952.3
Accumulated Amortization		(737.6)		(644.4)
Net Amount		5,017.3		1,307.9
Customer-related
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		1,165.1		716.9
Accumulated Amortization		(416.0)		(375.9)
Net Amount		749.1		341.0
Backlog
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		36.9
Accumulated Amortization		(0.4)
Net Amount		36.5
In-process technology
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		445.1		12.1
Accumulated Amortization		0.0		0.0
Net Amount		445.1		12.1
Distribution rights
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		0.3		0.3
Accumulated Amortization		(0.1)		(0.1)
Net Amount		0.2		0.2
Other
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		1.5		1.5
Accumulated Amortization		(0.8)		(0.7)
Net Amount		$ 0.7		$ 0.8
Minimum
Finite-Lived Intangible Assets, Net [Abstract]
Useful life (in years)		1 year
Maximum
Finite-Lived Intangible Assets, Net [Abstract]
Useful life (in years)		15 years
Cost of Sales
Finite-Lived Intangible Assets, Net [Abstract]
Amortization of Intangible Assets		$ 1.0	2.0
Operating Expense
Finite-Lived Intangible Assets, Net [Abstract]
Amortization of Intangible Assets		$ 133.8	$ 120.8
Microsemi Corporation
Finite-Lived Intangible Assets, Net [Abstract]
Useful life (in years)	9 years
Purchased intangible assets	$ 4,722.0
Microsemi Corporation | Core and developed technology
Finite-Lived Intangible Assets, Net [Abstract]
Useful life (in years)	10 years	10 years
Purchased intangible assets	$ 3,803.0	$ 3,800.0
Microsemi Corporation | Customer-related
Finite-Lived Intangible Assets, Net [Abstract]
Useful life (in years)		10 years
Purchased intangible assets		$ 448.1
Microsemi Corporation | Backlog
Finite-Lived Intangible Assets, Net [Abstract]
Useful life (in years)	1 year	1 year
Purchased intangible assets	$ 36.9	$ 36.9
Microsemi Corporation | In-process technology
Finite-Lived Intangible Assets, Net [Abstract]
Purchased intangible assets		$ 434.0