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Income Taxes - Summary of Changes in Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Balance, beginning of year	$ 192	$ 198
Increase based on tax positions related to current year	27	21
Decrease based on tax positions of prior years	0	(2)
Increase related to acquisitions	11	3
Settlements	(1)	(4)
Statute expirations	(52)	(21)
Foreign currency translation	5	(3)
Balance, ending of year	$ 182	$ 192

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Amount of unrecognized tax benefits.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 10B
-URI http://asc.fasb.org/extlink&oid=120406818&loc=SL37586934-109318

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-Topic 740
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-Section 50
-Paragraph 15A
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-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

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