Net Sales (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Total net sales	$ 7,634.4	$ 8,438.7	$ 6,820.9
Semiconductor products
Disaggregation of Revenue [Line Items]
Total net sales	7,531.1	8,277.7	6,698.9
Deferred revenue	933.0	757.7
Deferred revenue recognized	126.1	73.2
Semiconductor products | Accrued liabilities
Disaggregation of Revenue [Line Items]
Deferred revenue, to be recognized within next 12 months	261.8	121.4
Semiconductor products | Other noncurrent liabilities
Disaggregation of Revenue [Line Items]
Deferred revenue, non current	671.2	636.3
Distributors
Disaggregation of Revenue [Line Items]
Total net sales	3,620.8	3,993.6	3,248.7
Direct customers
Disaggregation of Revenue [Line Items]
Total net sales	3,910.3	4,284.1	3,450.2
Licensees
Disaggregation of Revenue [Line Items]
Total net sales	103.3	161.0	122.0
Mixed-signal Microcontrollers
Disaggregation of Revenue [Line Items]
Total net sales	4,272.4	4,755.7	3,814.8
Analog
Disaggregation of Revenue [Line Items]
Total net sales	2,016.4	2,376.9	1,939.1
Other
Disaggregation of Revenue [Line Items]
Total net sales	1,345.6	$ 1,306.1	$ 1,067.0
Long Term Supply Arrangement | Semiconductor products
Disaggregation of Revenue [Line Items]
Deferred revenue	839.7
Remaining performance obligation	$ 3,510.0
Long Term Supply Arrangement | Semiconductor products | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, percentage	25.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months
Long Term Supply Arrangement | Semiconductor products | Accrued liabilities
Disaggregation of Revenue [Line Items]
Deferred revenue, to be recognized within next 12 months	$ 175.4
Long Term Supply Arrangement | Semiconductor products | Other noncurrent liabilities
Disaggregation of Revenue [Line Items]
Deferred revenue, non current	664.3
Other Arrangement | Semiconductor products
Disaggregation of Revenue [Line Items]
Deferred revenue	$ 93.3