Intangible Assets and Goodwill - Intangible Assets, by Major Class (Details) - USD ($) $ in Millions		12 Months Ended
	May 29, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross amount		$ 8,345.4	$ 2,683.1
Accumulated amortization		(1,659.8)	(1,021.1)
Net amount		6,685.6	1,662.0
Projected Amortization Expense
2020		1,005.8
2021		944.1
2022		873.1
2023		680.0
2024		608.3
Amortization of acquired intangible assets		695.8	492.2	$ 346.3
Impairment of intangible assets		3.1	0.5	11.9
Cost of Sales
Projected Amortization Expense
Amortization of acquired intangible assets		9.6	6.1	4.0
Operating Expense
Projected Amortization Expense
Amortization of acquired intangible assets		$ 686.2	486.1	$ 342.3
Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)		1 year
Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)		15 years
Core and developed technology
Finite-Lived Intangible Assets [Line Items]
Gross amount		$ 7,413.0	1,952.3
Accumulated amortization		(1,112.9)	(644.4)
Net amount		6,300.1	1,307.9
Customer-related
Finite-Lived Intangible Assets [Line Items]
Gross amount		917.1	716.9
Accumulated amortization		(544.0)	(375.9)
Net amount		373.1	341.0
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Gross amount		7.7	12.1
Accumulated amortization		0.0	0.0
Net amount		7.7	12.1
Distribution rights
Finite-Lived Intangible Assets [Line Items]
Gross amount		0.3	0.3
Accumulated amortization		(0.2)	(0.1)
Net amount		0.1	0.2
Other
Finite-Lived Intangible Assets [Line Items]
Gross amount		7.3	1.5
Accumulated amortization		(2.7)	(0.7)
Net amount		$ 4.6	$ 0.8
Microsemi Corporation
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	13 years
Purchased intangible assets	$ 5,634.5
Microsemi Corporation | Core and developed technology
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	15 years	15 years
Purchased intangible assets	$ 4,569.1	$ 4,570.0
Microsemi Corporation | Customer-related
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	12 years	12 years
Purchased intangible assets	$ 200.2	$ 200.2
Microsemi Corporation | Backlog
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	1 year	1 year
Purchased intangible assets	$ 12.3	$ 12.3
Microsemi Corporation | In-process research and development
Finite-Lived Intangible Assets [Line Items]
In-process research and development		847.1
In-process technology reaching technological feasibility and reclassified		$ 851.5
Microsemi Corporation | Other
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	4 years	4 years
Purchased intangible assets	$ 5.8	$ 5.8