Intangible Assets and Goodwill - Goodwill by Reporting Segment (Details) $ in Millions	6 Months Ended	12 Months Ended
Sep. 30, 2021 USD ($)	Mar. 31, 2021 USD ($) unit
Goodwill By Reporting Segment [Line Items]
Goodwill	$ 6,673.6	$ 6,670.6
Number of reporting units \| unit		2
Semiconductor Products Reporting Unit
Goodwill By Reporting Segment [Line Items]
Goodwill	6,654.4	$ 6,651.4
Additions	3.0
Technology Licensing Reporting Unit
Goodwill By Reporting Segment [Line Items]
Goodwill	19.2	$ 19.2
Additions	$ 0.0

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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