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Taxes on Income - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance January 1	$ 1,537	$ 1,225	$ 1,893
Additions related to current year positions	306	298	199
Additions related to prior year positions	63	110	46
Reductions for tax positions of prior years	(230)	(4)	(454)
Settlements	(46)	(70)	(356)
Lapse of statute of limitations	(58)	(22)	(103)
Spin-off of Organon	(43)	0	0
Balance December 31	1,529	1,537	1,225
Unrecognized tax benefits, reduction resulting from divestiture of Merck's consumer care business	$ (58)	$ (22)	(103)
consumer care business
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Lapse of statute of limitations			(78)
Unrecognized tax benefits, reduction resulting from divestiture of Merck's consumer care business			$ (78)

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Unrecognized Tax Benefits, Decrease Resulting from Spinoff Transaction

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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.

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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
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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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