Net Sales (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Total net sales	$ 1,757.5	$ 1,352.1	$ 4,976.7	$ 3,971.3
Distributors
Disaggregation of Revenue [Line Items]
Total net sales	787.1	681.6	2,387.2	2,003.7
Direct customers
Disaggregation of Revenue [Line Items]
Total net sales	938.4	638.3	2,497.3	1,890.2
Licensees
Disaggregation of Revenue [Line Items]
Total net sales	32.0	32.2	92.2	77.4
Microcontrollers
Disaggregation of Revenue [Line Items]
Total net sales	972.2	726.3	2,768.7	2,145.8
Analog
Disaggregation of Revenue [Line Items]
Total net sales	500.5	372.8	1,423.5	1,104.7
Other
Disaggregation of Revenue [Line Items]
Total net sales	$ 284.8	$ 253.0	$ 784.5	$ 720.8