Net Sales (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Total net sales	$ 2,073.2	$ 1,649.8	$ 4,036.8	$ 3,219.2
Remaining performance obligation, expected to be recognized over next 12 months, percentage	63.00%		63.00%
Semiconductor products
Disaggregation of Revenue [Line Items]
Total net sales	$ 2,028.2	1,617.0	$ 3,953.9	3,159.0
Deferred revenue	237.3		237.3		$ 117.6
Deferred revenue, to be recognized within next 12 months	87.1		87.1
Semiconductor products | Accrued liabilities
Disaggregation of Revenue [Line Items]
Deferred revenue	88.3		88.3		$ 73.2
Distributors
Disaggregation of Revenue [Line Items]
Total net sales	958.3	816.7	1,871.4	1,600.1
Direct customers
Disaggregation of Revenue [Line Items]
Total net sales	1,069.9	800.3	2,082.5	1,558.9
Licensees
Disaggregation of Revenue [Line Items]
Total net sales	45.0	32.8	82.9	60.2
Microcontrollers
Disaggregation of Revenue [Line Items]
Total net sales	1,179.5	894.0	2,242.5	1,796.5
Analog
Disaggregation of Revenue [Line Items]
Total net sales	572.5	490.9	1,152.5	923.0
Other
Disaggregation of Revenue [Line Items]
Total net sales	321.2	$ 264.9	641.8	$ 499.7
Long Term Supply Arrangement | Semiconductor products
Disaggregation of Revenue [Line Items]
Deferred revenue	150.2		150.2
Long Term Supply Arrangement | Semiconductor products | Accrued liabilities
Disaggregation of Revenue [Line Items]
Deferred revenue	6.8		6.8
Long Term Supply Arrangement | Semiconductor products | Other noncurrent liabilities
Disaggregation of Revenue [Line Items]
Deferred revenue	143.4		143.4
Other Arrangement | Semiconductor products
Disaggregation of Revenue [Line Items]
Deferred revenue	$ 87.1		$ 87.1