Intangible Assets and Goodwill - Goodwill by Reporting Segment (Details) $ in Millions	3 Months Ended	9 Months Ended
Jun. 30, 2020 USD ($) unit	Dec. 31, 2020 USD ($)
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 6,664.8	$ 6,664.8
Goodwill, Ending Balance		6,670.6
Number of reporting units \| unit	2
Semiconductor Products Reporting Unit
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 6,645.6	6,645.6
Additions		5.8
Goodwill, Ending Balance		6,651.4
Technology Licensing Reporting Unit
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 19.2	19.2
Additions		0.0
Goodwill, Ending Balance		$ 19.2

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
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(10)(1))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=120320667&loc=SL49117168-202975

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

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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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

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- Definition

Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment.

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