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Goodwill - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 162	$ 121
Business combination	149	43
Foreign currency translation	19	(2)
Goodwill, Ending Balance	330	162
Automotive and Discrete Group (ADG) [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	43
Business combination	38	43
Foreign currency translation	10
Goodwill, Ending Balance	91	43
Microcontrollers and Digital ICs Group (MDG) [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	117	119
Business combination	111
Foreign currency translation	9	(2)
Goodwill, Ending Balance	237	117
Analog, MEMS & Sensors Group (AMS) [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	2	2
Goodwill, Ending Balance	$ 2	$ 2

X

- Definition

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.

+ References

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

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-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
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-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

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X

- Definition

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
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-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
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X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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X

- Definition

Amount of increase (decrease) from foreign currency translation adjustments and purchase accounting adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e961-128460

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