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Taxes on Income - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Income Tax Contingency [Line Items] |  |  |
Unrecognized tax benefits, reduction resulting from divestiture of Merck's consumer care business | $ (22) | $ (103) | $ (29)
Reconciliation of Unrecognized Tax Benefits [Roll Forward] |  |  |
Balance January 1 | 1,225 | 1,893 | 1,723
Additions related to current year positions | 298 | 199 | 221
Additions related to prior year positions | 110 | 46 | 142
Reductions for tax positions of prior years | (4) | (454) | (73)
Settlements | (70) | (356) | (91)
Lapse of statute of limitations | (22) | (103) | (29)
Balance December 31 | $ 1,537 | 1,225 | $ 1,893
consumer care business |  |  |
Income Tax Contingency [Line Items] |  |  |
Unrecognized tax benefits, reduction resulting from divestiture of Merck's consumer care business |  | (78) |
Reconciliation of Unrecognized Tax Benefits [Roll Forward] |  |  |
Lapse of statute of limitations |  | $ (78) |

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- Definition Amount of unrecognized tax benefits. + References 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 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319 + Details
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- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319 + Details
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- Definition Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319 + Details
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