$MRK
Merck & Co., Inc. Stock $mrk

$mrk Overview Financials Valuation SEC Filings Company Website

2021 Q4 Form 10-K Financial Statement

#000031015822000003 Filed on February 25, 2022

Income Statement

Concept	2021 Q4	2021	2020 Q4
Revenue	$13.52B	$48.70B	$12.52B
YoY Change	8.04%	17.31%	5.45%
Cost Of Revenue	$3.827B	$13.63B	$5.489B
YoY Change	-30.28%	0.06%	90.99%
Gross Profit	$9.694B	$35.08B	$7.026B
YoY Change	37.97%	25.73%	-21.88%
Gross Profit Margin	71.7%	72.02%	56.14%
Selling, General & Admin	$2.820B	$9.634B	$3.075B
YoY Change	-8.29%	7.58%	6.48%
% of Gross Profit	29.09%	27.46%	43.77%
Research & Development	$3.061B	$12.25B	$5.821B
YoY Change	-47.41%	-8.6%	144.99%
% of Gross Profit	31.58%	34.91%	82.85%
Depreciation & Amortization	$835.0M	$1.600B	$904.0M
YoY Change	-7.63%	-5.88%	-3.42%
% of Gross Profit	8.61%	4.56%	12.87%
Operating Expenses	$5.881B	$21.88B	$8.896B
YoY Change	-33.89%	-2.12%	69.0%
Operating Profit	$3.813B	$13.20B	-$1.870B
YoY Change	-303.9%	137.91%	-150.13%
Interest Expense	$110.0M	$806.0M	$122.0M
YoY Change	-9.84%	-3.01%	-271.83%
% of Operating Profit	2.88%	6.11%
Other Income/Expense, Net	$224.0M	$1.341B	$134.0M
YoY Change	67.16%	50.67%	-54.42%
Pretax Income	$3.909B	$13.88B	-$1.993B
YoY Change	-296.14%	136.72%	-171.41%
Income Tax	$85.00M	$1.521B	$98.00M
% Of Pretax Income	2.17%	10.96%
Net Earnings	$3.758B	$13.05B	-$2.094B
YoY Change	-279.47%	84.65%	-188.88%
Net Earnings / Revenue	27.79%	26.79%	-16.73%
Basic Earnings Per Share		$5.16
Diluted Earnings Per Share	$1.482M	$5.14	-$827.7K
COMMON SHARES
Basic Shares Outstanding	2.526B shares	2.530B shares	2.530B shares
Diluted Shares Outstanding		2.538B shares

Balance Sheet

Concept	2021 Q4	2021	2020 Q4
SHORT-TERM ASSETS
Cash & Short-Term Investments	$8.096B	$8.096B	$8.062B
YoY Change	0.42%	0.42%	-22.67%
Cash & Equivalents	$8.096B	$8.096B	$8.050B
Short-Term Investments			$0.00
Other Short-Term Assets	$6.987B	$6.987B	$4.674B
YoY Change	49.49%	26.1%	9.28%
Inventory	$5.953B	$5.953B	$5.554B
Prepaid Expenses
Receivables	$9.230B	$9.230B	$6.803B
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$30.27B	$30.27B	$27.76B
YoY Change	9.01%	9.01%	1.02%
LONG-TERM ASSETS
Property, Plant & Equipment	$19.28B	$19.28B	$17.00B
YoY Change	13.41%	7.19%	18.91%
Goodwill	$21.26B		$18.88B
YoY Change	12.62%		4.5%
Intangibles	$22.93B		$14.10B
YoY Change	62.63%		-0.67%
Long-Term Investments	$966.0M	$966.0M	$785.0M
YoY Change	23.06%	23.06%	-46.56%
Other Assets	$10.99B	$10.99B	$10.21B
YoY Change	7.59%	7.59%	79.2%
Total Long-Term Assets	$75.43B	$75.43B	$63.82B
YoY Change	18.18%	18.18%	12.14%
TOTAL ASSETS
Total Short-Term Assets	$30.27B	$30.27B	$27.76B
Total Long-Term Assets	$75.43B	$75.43B	$63.82B
Total Assets	$105.7B	$105.7B	$91.59B
YoY Change	15.4%	15.4%	8.52%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$4.609B	$4.609B	$4.327B
YoY Change	6.52%	0.33%	15.76%
Accrued Expenses	$13.86B	$13.86B	$13.05B
YoY Change	6.17%	6.17%	4.82%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$2.300B	$2.412B	$2.300B
YoY Change	0.0%	-62.49%	21.05%
Total Short-Term Liabilities	$23.87B	$23.87B	$27.33B
YoY Change	-12.64%	-12.64%	22.98%
LONG-TERM LIABILITIES
Long-Term Debt	$30.69B	$30.69B	$25.36B
YoY Change	21.02%	21.02%	11.54%
Other Long-Term Liabilities	$9.434B	$9.434B	$12.31B
YoY Change	-23.34%	-24.42%	2.81%
Total Long-Term Liabilities	$40.12B	$40.12B	$37.67B
YoY Change	6.53%	6.03%	8.53%
TOTAL LIABILITIES
Total Short-Term Liabilities	$23.87B	$23.87B	$27.33B
Total Long-Term Liabilities	$40.12B	$40.12B	$37.67B
Total Liabilities	$64.00B	$67.51B	$64.99B
YoY Change	-1.53%	1.87%	14.17%
SHAREHOLDERS EQUITY
Retained Earnings	$53.70B		$47.36B
YoY Change	13.37%		1.63%
Common Stock	$46.03B		$41.38B
YoY Change	11.24%		-0.17%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$57.11B		$56.79B
YoY Change	0.57%		1.5%
Treasury Stock Shares	1.049B shares		1.047B shares
Shareholders Equity	$38.18B	$38.18B	$25.32B
YoY Change
Total Liabilities & Shareholders Equity	$105.7B	$105.7B	$91.59B
YoY Change	15.4%	15.4%	8.52%

Cashflow Statement

Concept	2021 Q4	2021	2020 Q4
OPERATING ACTIVITIES
Net Income	$3.758B	$13.05B	-$2.094B
YoY Change	-279.47%	84.65%	-188.88%
Depreciation, Depletion And Amortization	$835.0M	$1.600B	$904.0M
YoY Change	-7.63%	-5.88%	-3.42%
Cash From Operating Activities	$5.031B	$14.11B	$4.006B
YoY Change	25.59%	37.61%	-16.44%
INVESTING ACTIVITIES
Capital Expenditures	-$1.208B	-$4.448B	-$1.514B
YoY Change	-20.21%	-5.04%	33.16%
Acquisitions		$179.0M
YoY Change		-86.89%
Other Investing Activities	-$10.84B	$91.00M	-$3.264B
YoY Change	232.14%	-172.8%	-972.73%
Cash From Investing Activities	-$12.05B	-$16.56B	-$4.778B
YoY Change	152.18%	75.32%	526.21%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net		$840.0M
YoY Change		-34.43%
Debt Paid & Issued, Net		$2.319B
YoY Change		18.5%
Cash From Financing Activities	5.207B	2.593B	1.372B
YoY Change	279.52%	-191.56%	-168.22%
NET CHANGE
Cash From Operating Activities	5.031B	14.11B	4.006B
Cash From Investing Activities	-12.05B	-16.56B	-4.778B
Cash From Financing Activities	5.207B	2.593B	1.372B
Net Change In Cash	-1.811B	$14.00M	600.0M
YoY Change	-401.83%	-100.79%	-70.3%
FREE CASH FLOW
Cash From Operating Activities	$5.031B	$14.11B	$4.006B
Capital Expenditures	-$1.208B	-$4.448B	-$1.514B
Free Cash Flow	$6.239B	$18.56B	$5.520B
YoY Change	13.03%	24.24%	-6.93%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2021	dei	Amendment Flag AmendmentFlag	false
CY2021	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
CY2021	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2021	dei	Entity Central Index Key EntityCentralIndexKey	0000310158
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#DeferredIncomeTaxesAndOtherAssetsNoncurrent
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#DeferredIncomeTaxesAndOtherAssetsNoncurrent
CY2021Q4	us-gaap	Operating Lease Liability Current Statement Of Financial Position Extensible List OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherLiabilitiesCurrent
CY2020Q4	us-gaap	Operating Lease Liability Current Statement Of Financial Position Extensible List OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherLiabilitiesCurrent
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent Statement Of Financial Position Extensible List OperatingLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherLiabilitiesNoncurrent
CY2021Q4	us-gaap	Operating Lease Liability Noncurrent Statement Of Financial Position Extensible List OperatingLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherLiabilitiesNoncurrent
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Award Vesting Rights Percentage SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage	0.3333
CY2021	dei	Document Type DocumentType	10-K
CY2021	dei	Document Annual Report DocumentAnnualReport	true
CY2021	dei	Document Period End Date DocumentPeriodEndDate	2021-12-31
CY2021	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2021	dei	Document Transition Report DocumentTransitionReport	false
CY2021	dei	Entity File Number EntityFileNumber	1-6571
CY2021	dei	Entity Registrant Name EntityRegistrantName	Merck & Co., Inc.
CY2021	dei	Entity Address Address Line1 EntityAddressAddressLine1	2000 Galloping Hill Road
CY2021	dei	Entity Address City Or Town EntityAddressCityOrTown	Kenilworth
CY2021	dei	Entity Address State Or Province EntityAddressStateOrProvince	NJ
CY2021	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	07033
CY2021	dei	City Area Code CityAreaCode	908
CY2021	dei	Local Phone Number LocalPhoneNumber	740-4000
CY2021	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	NJ
CY2021	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	22-1918501
CY2021	dei	Security12b Title Security12bTitle	Common Stock ($0.50 par value)
CY2021	dei	Trading Symbol TradingSymbol	MRK
CY2021	dei	Security Exchange Name SecurityExchangeName	NYSE
CY2022Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	2527733606	shares
CY2021Q2	dei	Entity Public Float EntityPublicFloat	196870000000	USD
CY2021	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2021	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2021	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2021	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2021	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2021	dei	Entity Small Business EntitySmallBusiness	false
CY2021	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2021	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2021	dei	Entity Shell Company EntityShellCompany	false
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CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-129000000	USD
CY2021	mrk	Costs Expenses And Other CostsExpensesAndOther	34825000000	USD
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CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	5863000000	USD
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CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1521000000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1340000000	USD
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CY2021	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	12358000000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	4523000000	USD
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CY2021	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	13000000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	4000000	USD
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CY2021	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	704000000	USD
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CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	17000000000	USD
CY2021Q4	us-gaap	Goodwill Goodwill	21264000000	USD
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CY2021Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	30690000000	USD
CY2020Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	25360000000	USD
CY2021Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	3441000000	USD
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CY2021Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Noncurrent LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent	0	USD
CY2020Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Noncurrent LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent	186000000	USD
CY2020Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.50
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CY2020Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	6500000000	shares
CY2020Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	3577103522	shares
CY2021Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	3577103522	shares
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CY2020Q4	us-gaap	Common Stock Value CommonStockValue	1788000000	USD
CY2021Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	44238000000	USD
CY2020Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	39588000000	USD
CY2021Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	53696000000	USD
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CY2021Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	1049499023	shares
CY2020Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	1046877695	shares
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CY2020Q4	us-gaap	Treasury Stock Value TreasuryStockValue	56787000000	USD
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CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	25317000000	USD
CY2021Q4	us-gaap	Minority Interest MinorityInterest	73000000	USD
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CY2021Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	38257000000	USD
CY2020Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	25404000000	USD
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CY2020Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	91588000000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	26882000000	USD
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CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.26
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	5820000000	USD
CY2019	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	4780000000	USD
CY2019	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	-66000000	USD
CY2019	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	21000000	USD
CY2019	us-gaap	Stockholders Equity Other StockholdersEquityOther	-611000000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	26001000000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	7067000000	USD
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CY2020	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.48
CY2020	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	6307000000	USD
CY2020	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	1281000000	USD
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CY2020	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	22000000	USD
CY2020	us-gaap	Stockholders Equity Other StockholdersEquityOther	-372000000	USD
CY2020Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	25404000000	USD
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CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	1756000000	USD
CY2021	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.64
CY2021	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	6715000000	USD
CY2021	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	840000000	USD
CY2021	us-gaap	Stockholders Equity Note Spinoff Transaction StockholdersEquityNoteSpinoffTransaction	5091000000	USD
CY2021	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	16000000	USD
CY2021	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	29000000	USD
CY2021	us-gaap	Stockholders Equity Other StockholdersEquityOther	-525000000	USD
CY2021Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	38257000000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	12358000000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	4523000000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	5606000000	USD
CY2021	us-gaap	Adjustment For Amortization AdjustmentForAmortization	1636000000	USD
CY2020	us-gaap	Adjustment For Amortization AdjustmentForAmortization	1817000000	USD
CY2019	us-gaap	Adjustment For Amortization AdjustmentForAmortization	1695000000	USD
CY2021	us-gaap	Depreciation Depreciation	1578000000	USD
CY2020	us-gaap	Depreciation Depreciation	1669000000	USD
CY2019	us-gaap	Depreciation Depreciation	1615000000	USD
CY2021	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	302000000	USD
CY2020	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	1718000000	USD
CY2019	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	1040000000	USD
CY2021	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	1940000000	USD
CY2020	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	1338000000	USD
CY2019	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	170000000	USD
CY2021	us-gaap	Research And Development Asset Acquired Other Than Through Business Combination Written Off ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationWrittenOff	1556000000	USD
CY2020	us-gaap	Research And Development Asset Acquired Other Than Through Business Combination Written Off ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationWrittenOff	0	USD
CY2019	us-gaap	Research And Development Asset Acquired Other Than Through Business Combination Written Off ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationWrittenOff	0	USD
CY2021	mrk	Research And Development Asset Acquired Other Than Through Business Combination Written Off Asset Acquisition Two ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationWrittenOffAssetAcquisitionTwo	0	USD
CY2020	mrk	Research And Development Asset Acquired Other Than Through Business Combination Written Off Asset Acquisition Two ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationWrittenOffAssetAcquisitionTwo	2660000000	USD
CY2019	mrk	Research And Development Asset Acquired Other Than Through Business Combination Written Off Asset Acquisition Two ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationWrittenOffAssetAcquisitionTwo	0	USD
CY2021	mrk	Research And Development Asset Acquired Other Than Through Business Combination Written Off Asset Acquisition Three ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationWrittenOffAssetAcquisitionThree	0	USD
CY2020	mrk	Research And Development Asset Acquired Other Than Through Business Combination Written Off Asset Acquisition Three ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationWrittenOffAssetAcquisitionThree	0	USD
CY2019	mrk	Research And Development Asset Acquired Other Than Through Business Combination Written Off Asset Acquisition Three ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationWrittenOffAssetAcquisitionThree	993000000	USD
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	187000000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-566000000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-560000000	USD
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	479000000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	441000000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	388000000	USD
CY2021	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-805000000	USD
CY2020	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-1294000000	USD
CY2019	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-354000000	USD
CY2021	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	2033000000	USD
CY2020	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	1002000000	USD
CY2019	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-92000000	USD
CY2021	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	674000000	USD
CY2020	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	895000000	USD
CY2019	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	473000000	USD
CY2021	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	405000000	USD
CY2020	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	684000000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	443000000	USD
CY2021	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	277000000	USD
CY2020	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	-1152000000	USD
CY2019	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	413000000	USD
CY2021	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	-540000000	USD
CY2020	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	814000000	USD
CY2019	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	-1889000000	USD
CY2021	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	484000000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-617000000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-733000000	USD
CY2021	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	1758000000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	2433000000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-70000000	USD
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	13122000000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	7617000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	8884000000	USD
CY2021	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	4448000000	USD
CY2020	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	4429000000	USD
CY2019	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	3369000000	USD
CY2021	us-gaap	Payments To Acquire Equity Securities Fv Ni PaymentsToAcquireEquitySecuritiesFvNi	0	USD
CY2020	us-gaap	Payments To Acquire Equity Securities Fv Ni PaymentsToAcquireEquitySecuritiesFvNi	1000000000	USD
CY2019	us-gaap	Payments To Acquire Equity Securities Fv Ni PaymentsToAcquireEquitySecuritiesFvNi	0	USD
CY2021	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	1000000	USD
CY2020	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	95000000	USD
CY2019	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	3202000000	USD
CY2021	us-gaap	Proceeds From Sale Maturity And Collections Of Investments ProceedsFromSaleMaturityAndCollectionsOfInvestments	1026000000	USD
CY2020	us-gaap	Proceeds From Sale Maturity And Collections Of Investments ProceedsFromSaleMaturityAndCollectionsOfInvestments	2812000000	USD
CY2019	us-gaap	Proceeds From Sale Maturity And Collections Of Investments ProceedsFromSaleMaturityAndCollectionsOfInvestments	8622000000	USD
CY2021	us-gaap	Payments To Acquire Business Two Net Of Cash Acquired PaymentsToAcquireBusinessTwoNetOfCashAcquired	11174000000	USD
CY2020	us-gaap	Payments To Acquire Business Two Net Of Cash Acquired PaymentsToAcquireBusinessTwoNetOfCashAcquired	0	USD
CY2019	us-gaap	Payments To Acquire Business Two Net Of Cash Acquired PaymentsToAcquireBusinessTwoNetOfCashAcquired	0	USD
CY2021	us-gaap	Payments To Acquire Business Three Net Of Cash Acquired PaymentsToAcquireBusinessThreeNetOfCashAcquired	1554000000	USD
CY2020	us-gaap	Payments To Acquire Business Three Net Of Cash Acquired PaymentsToAcquireBusinessThreeNetOfCashAcquired	0	USD
CY2019	us-gaap	Payments To Acquire Business Three Net Of Cash Acquired PaymentsToAcquireBusinessThreeNetOfCashAcquired	0	USD
CY2021	mrk	Payments To Acquire Business Four Net Of Cash Acquired PaymentsToAcquireBusinessFourNetOfCashAcquired	0	USD
CY2020	mrk	Payments To Acquire Business Four Net Of Cash Acquired PaymentsToAcquireBusinessFourNetOfCashAcquired	2696000000	USD
CY2019	mrk	Payments To Acquire Business Four Net Of Cash Acquired PaymentsToAcquireBusinessFourNetOfCashAcquired	0	USD
CY2021	mrk	Payments To Acquire Business Five Net Of Cash Acquired PaymentsToAcquireBusinessFiveNetOfCashAcquired	0	USD
CY2020	mrk	Payments To Acquire Business Five Net Of Cash Acquired PaymentsToAcquireBusinessFiveNetOfCashAcquired	2545000000	USD
CY2019	mrk	Payments To Acquire Business Five Net Of Cash Acquired PaymentsToAcquireBusinessFiveNetOfCashAcquired	0	USD
CY2021	mrk	Payments To Acquire Business Six Net Of Cash Acquired PaymentsToAcquireBusinessSixNetOfCashAcquired	0	USD
CY2020	mrk	Payments To Acquire Business Six Net Of Cash Acquired PaymentsToAcquireBusinessSixNetOfCashAcquired	0	USD
CY2019	mrk	Payments To Acquire Business Six Net Of Cash Acquired PaymentsToAcquireBusinessSixNetOfCashAcquired	3620000000	USD
CY2021	mrk	Payments To Acquire Business Seven Net Of Cash Acquired PaymentsToAcquireBusinessSevenNetOfCashAcquired	0	USD
CY2020	mrk	Payments To Acquire Business Seven Net Of Cash Acquired PaymentsToAcquireBusinessSevenNetOfCashAcquired	0	USD
CY2019	mrk	Payments To Acquire Business Seven Net Of Cash Acquired PaymentsToAcquireBusinessSevenNetOfCashAcquired	1040000000	USD
CY2021	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	179000000	USD
CY2020	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	1365000000	USD
CY2019	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	294000000	USD
CY2021	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	91000000	USD
CY2020	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-125000000	USD
CY2019	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-374000000	USD
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-16421000000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-9193000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-2529000000	USD
CY2021	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-3986000000	USD
CY2020	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	2549000000	USD
CY2019	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-3710000000	USD
CY2021	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	2319000000	USD
CY2020	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	1957000000	USD
CY2019	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	0	USD
CY2021	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	7936000000	USD
CY2020	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	4419000000	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	4958000000	USD
CY2021	mrk	Disposal Group Including Discontinued Operations Distribution Received DisposalGroupIncludingDiscontinuedOperationsDistributionReceived	9000000000	USD
CY2020	mrk	Disposal Group Including Discontinued Operations Distribution Received DisposalGroupIncludingDiscontinuedOperationsDistributionReceived	0	USD
CY2019	mrk	Disposal Group Including Discontinued Operations Distribution Received DisposalGroupIncludingDiscontinuedOperationsDistributionReceived	0	USD
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	840000000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1281000000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	4780000000	USD
CY2021	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	6610000000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	6215000000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	5695000000	USD
CY2021	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	202000000	USD
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	89000000	USD
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	361000000	USD
CY2021	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-286000000	USD
CY2020	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-436000000	USD
CY2019	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	5000000	USD
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	3097000000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	-2832000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	-8861000000	USD
CY2021	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	987000000	USD
CY2020	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	2636000000	USD
CY2019	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	4556000000	USD
CY2021	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-134000000	USD
CY2020	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-250000000	USD
CY2019	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-100000000	USD
CY2021	us-gaap	Cash Provided By Used In Financing Activities Discontinued Operations CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations	-504000000	USD
CY2020	us-gaap	Cash Provided By Used In Financing Activities Discontinued Operations CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations	0	USD
CY2019	us-gaap	Cash Provided By Used In Financing Activities Discontinued Operations CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations	0	USD
CY2021	us-gaap	Net Cash Provided By Used In Discontinued Operations NetCashProvidedByUsedInDiscontinuedOperations	349000000	USD
CY2020	us-gaap	Net Cash Provided By Used In Discontinued Operations NetCashProvidedByUsedInDiscontinuedOperations	2386000000	USD
CY2019	us-gaap	Net Cash Provided By Used In Discontinued Operations NetCashProvidedByUsedInDiscontinuedOperations	4456000000	USD
CY2021	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-133000000	USD
CY2020	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	253000000	USD
CY2019	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	17000000	USD
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	14000000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-1769000000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	1967000000	USD
CY2020Q4	us-gaap	Restricted Cash RestrictedCash	103000000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	8153000000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	9934000000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	7967000000	USD
CY2021Q4	us-gaap	Disposal Group Including Discontinued Operation Cash And Cash Equivalents DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents	0	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Cash And Cash Equivalents DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents	12000000	USD
CY2019Q4	us-gaap	Disposal Group Including Discontinued Operation Cash And Cash Equivalents DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents	0	USD
CY2021Q4	us-gaap	Restricted Cash RestrictedCash	71000000	USD
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	8167000000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	8153000000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	9934000000	USD
CY2021	us-gaap	Nature Of Operations NatureOfOperations	Nature of Operations<div style="margin-top:5pt;text-align:justify;text-indent:45pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Merck & Co., Inc. (Merck or the Company) is a global health care company that delivers innovative health solutions through its prescription medicines, vaccines, biologic therapies and animal health products. The Company’s operations are principally managed on a products basis and include two operating segments, which are the Pharmaceutical and Animal Health segments, both of which are reportable segments. </span></div><div style="margin-top:5pt;text-align:justify;text-indent:45pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Pharmaceutical segment includes human health pharmaceutical and vaccine products. Human health pharmaceutical products consist of therapeutic and preventive agents, generally sold by prescription, for the treatment of human disorders. The Company sells these human health pharmaceutical products primarily to drug wholesalers and retailers, hospitals, government agencies and managed health care providers such as health maintenance organizations, pharmacy benefit managers and other institutions. Human health vaccine products consist of preventive pediatric, adolescent and adult vaccines. The Company sells these human health vaccines primarily to physicians, wholesalers, physician distributors and government entities. </span></div><div style="margin-top:5pt;text-align:justify;text-indent:45pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Animal Health segment discovers, develops, manufactures and markets a wide range of veterinary pharmaceutical and vaccine products, as well as health management solutions and services, for the prevention, treatment and control of disease in all major livestock and companion animal species. The Company also offers an extensive suite of digitally connected identification, traceability and monitoring products. The Company sells its products to veterinarians, distributors and animal producers. </span></div><div style="margin-top:5pt;text-align:justify;text-indent:45pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company previously had a Healthcare Services segment that provided services and solutions focused on engagement, health analytics and clinical services to improve the value of care delivered to patients. The Company divested the remaining businesses in this segment during the first quarter of 2020.</span></div><div style="margin-top:9pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Spin-Off of Organon & Co. </span></div><div style="margin-top:3pt;text-align:justify;text-indent:45pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On June 2, 2021, Merck completed the spin-off of products from its women’s health, biosimilars and established brands businesses into a new, independent, publicly traded company named Organon & Co. (Organon) through a distribution of Organon’s publicly traded stock to Company shareholders. The distribution is expected to qualify and has been treated as tax-free to the Company and its shareholders for U.S. federal income tax purposes. The established brands included in the transaction consisted of dermatology, non-opioid pain management, respiratory, select cardiovascular products, as well as the rest of Merck’s diversified brands franchise. Merck’s existing research pipeline programs continue to be owned and developed within Merck as planned. The historical results of the businesses that were contributed to Organon in the spin-off have been reflected as discontinued operations in the Company’s consolidated financial statements through the date of the spin-off (see Note 3).</span></div>
CY2021	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	2	segment
CY2021	mrk	Sales Discounts SalesDiscounts	12300000000	USD
CY2020	mrk	Sales Discounts SalesDiscounts	11400000000	USD
CY2019	mrk	Sales Discounts SalesDiscounts	9900000000	USD
CY2021Q4	mrk	Accrual For Chargebacks AccrualForChargebacks	207000000	USD
CY2021Q4	mrk	Accrual For Rebates AccrualForRebates	2600000000	USD
CY2020Q4	mrk	Accrual For Chargebacks AccrualForChargebacks	208000000	USD
CY2020Q4	mrk	Accrual For Rebates AccrualForRebates	2600000000	USD
CY2021	mrk	Revenue Recognition Goods Goods Return Period Afterto Expiration Date RevenueRecognitionGoodsGoodsReturnPeriodAftertoExpirationDate	P12M
CY2021	us-gaap	Depreciation Depreciation	1600000000	USD
CY2020	us-gaap	Depreciation Depreciation	1700000000	USD
CY2019	us-gaap	Depreciation Depreciation	1600000000	USD
CY2021	us-gaap	Advertising Expense AdvertisingExpense	2000000000	USD
CY2020	us-gaap	Advertising Expense AdvertisingExpense	1800000000	USD
CY2019	us-gaap	Advertising Expense AdvertisingExpense	1900000000	USD
CY2021	us-gaap	Use Of Estimates UseOfEstimates	<span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Use of Estimates — </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The consolidated financial statements are prepared in conformity with accounting principles generally accepted in the U.S. (GAAP) and, accordingly, include certain amounts that are based on management’s best estimates and judgments. Estimates are used when accounting for amounts recorded in connection with acquisitions, including initial fair value determinations of assets and liabilities (primarily IPR&D, other intangible assets and contingent consideration), as well as subsequent fair value measurements. Additionally, estimates are used in determining such items as provisions for sales discounts and returns, depreciable and amortizable lives, recoverability of inventories, including those produced in preparation for product launches, amounts recorded for contingencies, environmental liabilities, accruals for contingent sales-based milestone payments and other reserves, pension and other postretirement benefit plan assumptions, share-based compensation assumptions, restructuring costs, impairments of long-lived assets (including intangible assets and goodwill) and investments, and taxes on income. Because of the uncertainty inherent in such estimates, actual results may differ from these estimates.</span>
CY2021	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	Reclassifications — Certain reclassifications have been made to prior year amounts to conform to the current year presentation.
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CY2021	us-gaap	Disposal Group Including Discontinued Operation Other Expense DisposalGroupIncludingDiscontinuedOperationOtherExpense	556000000	USD
CY2020	us-gaap	Disposal Group Including Discontinued Operation Other Expense DisposalGroupIncludingDiscontinuedOperationOtherExpense	743000000	USD
CY2021	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	2512000000	USD
CY2020	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	6476000000	USD
CY2019	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	7719000000	USD
CY2021	us-gaap	Disposal Group Including Discontinued Operation Costs Of Goods Sold DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold	789000000	USD
CY2020	us-gaap	Disposal Group Including Discontinued Operation Costs Of Goods Sold DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold	1867000000	USD
CY2019	us-gaap	Disposal Group Including Discontinued Operation Costs Of Goods Sold DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSold	2096000000	USD
CY2021	us-gaap	Disposal Group Including Discontinued Operation General And Administrative Expense DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense	877000000	USD
CY2020	us-gaap	Disposal Group Including Discontinued Operation General And Administrative Expense DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense	1513000000	USD
CY2019	us-gaap	Disposal Group Including Discontinued Operation General And Administrative Expense DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense	1160000000	USD
CY2021	mrk	Disposal Group Including Discontinued Operations Research And Development Expenses DisposalGroupIncludingDiscontinuedOperationsResearchAndDevelopmentExpenses	103000000	USD
CY2020	mrk	Disposal Group Including Discontinued Operations Research And Development Expenses DisposalGroupIncludingDiscontinuedOperationsResearchAndDevelopmentExpenses	161000000	USD
CY2019	mrk	Disposal Group Including Discontinued Operations Research And Development Expenses DisposalGroupIncludingDiscontinuedOperationsResearchAndDevelopmentExpenses	148000000	USD
CY2021	mrk	Disposal Group Including Discontinued Operations Restructuring Costs DisposalGroupIncludingDiscontinuedOperationsRestructuringCosts	1000000	USD
CY2020	mrk	Disposal Group Including Discontinued Operations Restructuring Costs DisposalGroupIncludingDiscontinuedOperationsRestructuringCosts	3000000	USD
CY2019	mrk	Disposal Group Including Discontinued Operations Restructuring Costs DisposalGroupIncludingDiscontinuedOperationsRestructuringCosts	12000000	USD
CY2021	mrk	Disposal Group Including Discontinued Operation Other Income Expense Net DisposalGroupIncludingDiscontinuedOperationOtherIncomeExpenseNet	15000000	USD
CY2020	mrk	Disposal Group Including Discontinued Operation Other Income Expense Net DisposalGroupIncludingDiscontinuedOperationOtherIncomeExpenseNet	-4000000	USD
CY2019	mrk	Disposal Group Including Discontinued Operation Other Income Expense Net DisposalGroupIncludingDiscontinuedOperationOtherIncomeExpenseNet	-10000000	USD
CY2021	us-gaap	Disposal Group Including Discontinued Operation Operating Expense DisposalGroupIncludingDiscontinuedOperationOperatingExpense	1755000000	USD
CY2020	us-gaap	Disposal Group Including Discontinued Operation Operating Expense DisposalGroupIncludingDiscontinuedOperationOperatingExpense	3548000000	USD
CY2019	us-gaap	Disposal Group Including Discontinued Operation Operating Expense DisposalGroupIncludingDiscontinuedOperationOperatingExpense	3426000000	USD
CY2021	us-gaap	Discontinued Operation Income Loss From Discontinued Operation During Phase Out Period Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax	757000000	USD
CY2020	us-gaap	Discontinued Operation Income Loss From Discontinued Operation During Phase Out Period Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax	2928000000	USD
CY2019	us-gaap	Discontinued Operation Income Loss From Discontinued Operation During Phase Out Period Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax	4293000000	USD
CY2021	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Discontinued Operation During Phase Out Period DiscontinuedOperationTaxEffectOfIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriod	50000000	USD
CY2020	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Discontinued Operation During Phase Out Period DiscontinuedOperationTaxEffectOfIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriod	369000000	USD
CY2019	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Discontinued Operation During Phase Out Period DiscontinuedOperationTaxEffectOfIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriod	122000000	USD
CY2021	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	707000000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	2559000000	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	4171000000	USD
CY2021	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	3000000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	11000000	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	18000000	USD
CY2021	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	704000000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	2548000000	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	4153000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Cash And Cash Equivalents DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents	12000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Accounts Notes And Loans Receivable Net DisposalGroupIncludingDiscontinuedOperationAccountsNotesAndLoansReceivableNet	1048000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Inventory1 DisposalGroupIncludingDiscontinuedOperationInventory1	756000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Other Current Assets DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets	867000000	USD
CY2020Q4	us-gaap	Assets Of Disposal Group Including Discontinued Operation Current AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent	2683000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Property Plant And Equipment DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment	986000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Goodwill1 DisposalGroupIncludingDiscontinuedOperationGoodwill1	1356000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Intangible Assets DisposalGroupIncludingDiscontinuedOperationIntangibleAssets	503000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Other Assets DisposalGroupIncludingDiscontinuedOperationOtherAssets	330000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Assets Noncurrent DisposalGroupIncludingDiscontinuedOperationAssetsNoncurrent	3175000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Accounts Payable DisposalGroupIncludingDiscontinuedOperationAccountsPayable	267000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Accrued Liabilities DisposalGroupIncludingDiscontinuedOperationAccruedLiabilities	841000000	USD
CY2020Q4	mrk	Disposal Group Including Discontinued Operation Accrual Reversal Income Taxes Payable Current DisposalGroupIncludingDiscontinuedOperationAccrualReversalIncomeTaxesPayableCurrent	-22000000	USD
CY2020Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Current LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent	1086000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Deferred Tax Liabilities DisposalGroupIncludingDiscontinuedOperationDeferredTaxLiabilities	10000000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Other Noncurrent Liabilities DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities	176000000	USD
CY2020Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Noncurrent LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent	186000000	USD
CY2021Q2	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation	5100000000	USD
CY2021Q2	mrk	Disposal Group Including Discontinued Operations Debt DisposalGroupIncludingDiscontinuedOperationsDebt	9400000000	USD
CY2021Q2	us-gaap	Disposal Group Including Discontinued Operation Goodwill1 DisposalGroupIncludingDiscontinuedOperationGoodwill1	1400000000	USD
CY2021Q2	us-gaap	Disposal Group Including Discontinued Operation Property Plant And Equipment DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment	981000000	USD
CY2021Q2	us-gaap	Disposal Group Including Discontinued Operation Cash DisposalGroupIncludingDiscontinuedOperationCash	929000000	USD
CY2021Q2	us-gaap	Disposal Group Including Discontinued Operation Inventory1 DisposalGroupIncludingDiscontinuedOperationInventory1	815000000	USD
CY2021Q2	us-gaap	Disposal Group Including Discontinued Operation Intangible Assets DisposalGroupIncludingDiscontinuedOperationIntangibleAssets	519000000	USD
CY2021Q2	us-gaap	Disposal Group Including Discontinued Operation Other Liabilities DisposalGroupIncludingDiscontinuedOperationOtherLiabilities	328000000	USD
CY2021	mrk	Supply Commitment Minimum Number Of Markets SupplyCommitmentMinimumNumberOfMarkets	30	market
CY2021	mrk	Number Of Low And Middle Income Countries Reached Through Supply And Access Approach NumberOfLowAndMiddleIncomeCountriesReachedThroughSupplyAndAccessApproach	100	country
CY2021Q4	us-gaap	Restructuring And Related Cost Expected Cost1 RestructuringAndRelatedCostExpectedCost1	3500000000	USD
CY2021	mrk	Estimate Of Cumulative Pre Tax Costs That Will Result In Cash Outlays EstimateOfCumulativePreTaxCostsThatWillResultInCashOutlays	0.70
CY2021	mrk	Estimate Of Cumulative Pre Tax Costs That Will Be Noncash EstimateOfCumulativePreTaxCostsThatWillBeNoncash	0.30
CY2021	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	868000000	USD
CY2020	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	880000000	USD
CY2019	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	915000000	USD
CY2021Q4	us-gaap	Restructuring And Related Cost Cost Incurred To Date1 RestructuringAndRelatedCostCostIncurredToDate1	2700000000	USD
CY2021	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	868000000	USD
CY2020	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	880000000	USD
CY2019	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	915000000	USD
CY2019Q4	us-gaap	Restructuring Reserve RestructuringReserve	715000000	USD
CY2020	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	880000000	USD
CY2020	us-gaap	Payments For Restructuring PaymentsForRestructuring	779000000	USD
CY2020	mrk	Restructuring Reserve Increase Decrease Noncash Activity RestructuringReserveIncreaseDecreaseNoncashActivity	-230000000	USD
CY2020Q4	us-gaap	Restructuring Reserve RestructuringReserve	586000000	USD
CY2021	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	868000000	USD
CY2021	us-gaap	Payments For Restructuring PaymentsForRestructuring	608000000	USD
CY2021	mrk	Restructuring Reserve Increase Decrease Noncash Activity RestructuringReserveIncreaseDecreaseNoncashActivity	-209000000	USD
CY2021Q4	us-gaap	Restructuring Reserve RestructuringReserve	637000000	USD
CY2021Q4	us-gaap	Derivative Assets DerivativeAssets	549000000	USD
CY2021Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	121000000	USD
CY2021Q4	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	32958000000	USD
CY2020Q4	us-gaap	Derivative Assets DerivativeAssets	182000000	USD
CY2020Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	525000000	USD
CY2020Q4	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	32784000000	USD
CY2021Q4	us-gaap	Derivative Assets DerivativeAssets	549000000	USD
CY2021Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	121000000	USD
CY2020Q4	us-gaap	Derivative Assets DerivativeAssets	182000000	USD
CY2020Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	525000000	USD
CY2021Q4	us-gaap	Derivative Asset Not Offset Policy Election Deduction DerivativeAssetNotOffsetPolicyElectionDeduction	110000000	USD
CY2021Q4	us-gaap	Derivative Liability Not Offset Policy Election Deduction DerivativeLiabilityNotOffsetPolicyElectionDeduction	110000000	USD
CY2020Q4	us-gaap	Derivative Asset Not Offset Policy Election Deduction DerivativeAssetNotOffsetPolicyElectionDeduction	156000000	USD
CY2020Q4	us-gaap	Derivative Liability Not Offset Policy Election Deduction DerivativeLiabilityNotOffsetPolicyElectionDeduction	156000000	USD
CY2021Q4	us-gaap	Derivative Collateral Obligation To Return Cash DerivativeCollateralObligationToReturnCash	164000000	USD
CY2021Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	0	USD
CY2020Q4	us-gaap	Derivative Collateral Obligation To Return Cash DerivativeCollateralObligationToReturnCash	0	USD
CY2020Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	36000000	USD
CY2021Q4	us-gaap	Derivative Asset Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeAssetFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	275000000	USD
CY2021Q4	us-gaap	Derivative Liability Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeLiabilityFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	11000000	USD
CY2020Q4	us-gaap	Derivative Asset Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeAssetFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	26000000	USD
CY2020Q4	us-gaap	Derivative Liability Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeLiabilityFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	333000000	USD
CY2021	us-gaap	Revenues Revenues	48704000000	USD
CY2020	us-gaap	Revenues Revenues	41518000000	USD
CY2019	us-gaap	Revenues Revenues	39121000000	USD
CY2021	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	1341000000	USD
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	890000000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-129000000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	1756000000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-441000000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-648000000	USD
CY2021	us-gaap	Derivative Instruments Gain Loss Reclassification From Accumulated Oci To Income Estimated Net Amount To Be Transferred DerivativeInstrumentsGainLossReclassificationFromAccumulatedOCIToIncomeEstimatedNetAmountToBeTransferred	170000000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	86000000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	0	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	0	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	86000000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	89000000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	0	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	0	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	89000000	USD
CY2021Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	1647000000	USD
CY2020Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	1787000000	USD
CY2021Q4	mrk	Debt Securitiesand Equity Securities Fvni DebtSecuritiesandEquitySecuritiesFVNI	1733000000	USD
CY2020Q4	mrk	Debt Securitiesand Equity Securities Fvni DebtSecuritiesandEquitySecuritiesFVNI	1876000000	USD
CY2021	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-232000000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	163000000	USD
CY2021Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	596000000	USD
CY2020Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	586000000	USD
CY2021	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	110000000	USD
CY2021	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	1000000	USD
CY2020	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	62000000	USD
CY2020	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	3000000	USD
CY2021Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentCumulativeAmount	234000000	USD
CY2021Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount	7000000	USD
CY2021Q4	us-gaap	Equity Securities Fvni Noncurrent EquitySecuritiesFVNINoncurrent	1700000000	USD
CY2020Q4	us-gaap	Equity Securities Fvni Noncurrent EquitySecuritiesFVNINoncurrent	800000000	USD
CY2021	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	1400000000	USD
CY2020	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	583000000	USD
CY2019	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	-113000000	USD
CY2020Q4	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	841000000	USD
CY2019Q4	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	767000000	USD
CY2021	us-gaap	Business Combination Consideration Transferred Liabilities Incurred BusinessCombinationConsiderationTransferredLiabilitiesIncurred	0	USD
CY2020	us-gaap	Business Combination Consideration Transferred Liabilities Incurred BusinessCombinationConsiderationTransferredLiabilitiesIncurred	97000000	USD
CY2021	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	57000000	USD
CY2020	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	83000000	USD
CY2021	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements	109000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements	106000000	USD
CY2021	mrk	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Other FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityOther	12000000	USD
CY2020	mrk	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Other FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityOther	0	USD
CY2021Q4	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	777000000	USD
CY2020Q4	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	841000000	USD
CY2021Q4	us-gaap	Business Combination Contingent Consideration Liability Current BusinessCombinationContingentConsiderationLiabilityCurrent	151000000	USD
CY2021Q4	us-gaap	Debt Instrument Fair Value DebtInstrumentFairValue	35700000000	USD
CY2021Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	33100000000	USD
CY2020Q4	us-gaap	Debt Instrument Fair Value DebtInstrumentFairValue	36000000000	USD
CY2020Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	31800000000	USD
CY2021Q4	us-gaap	Accounts Receivable Sale AccountsReceivableSale	2800000000	USD
CY2020Q4	us-gaap	Accounts Receivable Sale AccountsReceivableSale	2100000000	USD
CY2021Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	62000000	USD
CY2020Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	102000000	USD
CY2021Q4	us-gaap	Derivative Collateral Obligation To Return Cash DerivativeCollateralObligationToReturnCash	164000000	USD
CY2020Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	36000000	USD
CY2021Q4	mrk	Long Term Debt Interest Payable Year Four LongTermDebtInterestPayableYearFour	771000000	USD
CY2021Q4	us-gaap	Inventory Finished Goods InventoryFinishedGoods	1747000000	USD
CY2020Q4	us-gaap	Inventory Finished Goods InventoryFinishedGoods	1610000000	USD
CY2021Q4	us-gaap	Inventory Work In Process And Raw Materials InventoryWorkInProcessAndRawMaterials	6220000000	USD
CY2020Q4	us-gaap	Inventory Work In Process And Raw Materials InventoryWorkInProcessAndRawMaterials	5949000000	USD
CY2021Q4	us-gaap	Other Inventory Supplies OtherInventorySupplies	196000000	USD
CY2020Q4	us-gaap	Other Inventory Supplies OtherInventorySupplies	146000000	USD
CY2021Q4	us-gaap	Inventory Gross InventoryGross	8163000000	USD
CY2020Q4	us-gaap	Inventory Gross InventoryGross	7705000000	USD
CY2021Q4	us-gaap	Inventory Lifo Reserve InventoryLIFOReserve	16000000	USD
CY2020Q4	us-gaap	Inventory Lifo Reserve InventoryLIFOReserve	81000000	USD
CY2021Q4	mrk	Inventory Net And Inventory Noncurrent InventoryNetAndInventoryNoncurrent	8147000000	USD
CY2020Q4	mrk	Inventory Net And Inventory Noncurrent InventoryNetAndInventoryNoncurrent	7624000000	USD
CY2021Q4	us-gaap	Inventory Net InventoryNet	5953000000	USD
CY2020Q4	us-gaap	Inventory Net InventoryNet	5554000000	USD
CY2021Q4	us-gaap	Inventory Noncurrent InventoryNoncurrent	2194000000	USD
CY2020Q4	us-gaap	Inventory Noncurrent InventoryNoncurrent	2070000000	USD
CY2021Q4	us-gaap	Lifo Inventory Amount LIFOInventoryAmount	3300000000	USD
CY2020Q4	us-gaap	Lifo Inventory Amount LIFOInventoryAmount	2800000000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	18069000000	USD
CY2020	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	847000000	USD
CY2020	us-gaap	Goodwill Written Off Related To Sale Of Business Unit GoodwillWrittenOffRelatedToSaleOfBusinessUnit	54000000	USD
CY2020	us-gaap	Goodwill Other Increase Decrease GoodwillOtherIncreaseDecrease	20000000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	18882000000	USD
CY2021	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	2436000000	USD
CY2021	us-gaap	Goodwill Other Increase Decrease GoodwillOtherIncreaseDecrease	-54000000	USD
CY2021Q4	us-gaap	Goodwill Goodwill	21264000000	USD
CY2020Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	531000000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	1600000000	USD
CY2021Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	531000000	USD
CY2021Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	42438000000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	19505000000	USD
CY2021Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	22933000000	USD
CY2020Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	33237000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	19136000000	USD
CY2020Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	14101000000	USD
CY2019	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	705000000	USD
CY2019	us-gaap	Impairment Of Intangible Assets Indefinitelived Excluding Goodwill ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill	172000000	USD
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1600000000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1800000000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1700000000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	1700000000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	1600000000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	1400000000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	1400000000	USD
CY2021Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	2300000000	USD
CY2020Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	2300000000	USD
CY2021Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	30690000000	USD
CY2020Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	25360000000	USD
CY2021Q4	us-gaap	Debt Instrument Face Amount DebtInstrumentFaceAmount	8000000000	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	2300000000	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	1700000000	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	1300000000	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	2500000000	USD
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	2300000000	USD
CY2021Q4	mrk	Long Term Debt Interest Payable Year One LongTermDebtInterestPayableYearOne	910000000	USD
CY2021Q4	mrk	Long Term Debt Interest Payable Year Two LongTermDebtInterestPayableYearTwo	875000000	USD
CY2021Q4	mrk	Long Term Debt Interest Payable Year Three LongTermDebtInterestPayableYearThree	838000000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	176000000	USD
CY2021Q4	mrk	Long Term Debt Interest Payable Year Five LongTermDebtInterestPayableYearFive	743000000	USD
CY2021Q4	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	6000000000	USD
CY2021	us-gaap	Operating Lease Cost OperatingLeaseCost	343000000	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	340000000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	333000000	USD
CY2021	us-gaap	Operating Lease Payments OperatingLeasePayments	340000000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	334000000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	275000000	USD
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	117000000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	473000000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	125000000	USD
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	1586000000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	1688000000	USD
CY2021Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	304000000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	291000000	USD
CY2021Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	1225000000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	1335000000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	1529000000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	1626000000	USD
CY2021Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P7Y
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P8Y
CY2021Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.026
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.028
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	336000000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	292000000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	242000000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	178000000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	146000000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	511000000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	1705000000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	1529000000	USD
CY2021Q4	mrk	Lessee Operating Lease Lease Notyet Commenced Amount LesseeOperatingLeaseLeaseNotyetCommencedAmount	86000000	USD
CY2021Q4	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	40000000	USD
CY2020Q4	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	43000000	USD
CY2021	mrk	Term For Paying Off Environmental Liabilities TermForPayingOffEnvironmentalLiabilities	P15Y
CY2021	us-gaap	Environmental Exit Costs Reasonably Possible Additional Loss EnvironmentalExitCostsReasonablyPossibleAdditionalLoss	40000000	USD
CY2021Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	6500000000	shares
CY2021Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000	shares
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	93000000	shares
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Award Requisite Service Period1 ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1	P3Y
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Award Requisite Service Period1 ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1	P3Y
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Award Requisite Service Period1 ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1	P3Y
CY2021	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	498000000	USD
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	475000000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	417000000	USD
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	479000000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	441000000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	388000000	USD
CY2021	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	69000000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	65000000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	57000000	USD
CY2021	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	75.99
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	77.67
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	80.05
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	9.80
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	9.93
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	10.63
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.031
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.031
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.032
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.010
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.004
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.024
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.209
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.221
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.187
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y10M24D
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y9M18D
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y10M24D
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	19446000	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	63.64
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod	4781000	shares
CY2021	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	75.99
CY2021	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	3728000	shares
CY2021	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	54.14
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	626000	shares
CY2021	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	73.97
CY2021	mrk	Share Based Compensation Arrangement By Share Based Payment Award Options Transferred In Spinoff Transaction ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsTransferredInSpinoffTransaction	1947000	shares
CY2021	mrk	Share Based Compensation Arrangement By Share Based Payment Award Options Transferred In Spinoff Transaction Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsTransferredInSpinoffTransactionWeightedAverageGrantDateFairValue	72.15
CY2021	mrk	Share Based Compensation Arrangement By Share Based Payment Award Options Spin Off Adjustment ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsSpinOffAdjustment	646000	shares
CY2021	mrk	Share Based Compensation Arrangement By Share Based Payment Award Options Spin Off Adjustment Weighted Average Exercise ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsSpinOffAdjustmentWeightedAverageExercise	0
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	18572000	shares
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	65.27
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P6Y3M18D
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	213000000	USD
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber	17829000	shares
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice	64.90
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1	P6Y2M12D
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue	212000000	USD
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	12136000	shares
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	60.41
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P5Y
CY2021Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	198000000	USD
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	106000000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	51000000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	295000000	USD
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	27000000	USD
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	25000000	USD
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	27000000	USD
CY2021	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	202000000	USD
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	89000000	USD
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	361000000	USD
CY2021Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	699000000	USD
CY2021	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P1Y10M24D
CY2021Q4	us-gaap	Defined Benefit Plan Accumulated Benefit Obligation DefinedBenefitPlanAccumulatedBenefitObligation	24900000000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Accumulated Benefit Obligation DefinedBenefitPlanAccumulatedBenefitObligation	26300000000	USD
CY2021	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	158000000	USD
CY2020	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	158000000	USD
CY2019	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	143000000	USD
CY2021	us-gaap	Investment Income Interest InvestmentIncomeInterest	36000000	USD
CY2020	us-gaap	Investment Income Interest InvestmentIncomeInterest	59000000	USD
CY2019	us-gaap	Investment Income Interest InvestmentIncomeInterest	274000000	USD
CY2021	us-gaap	Interest Expense InterestExpense	806000000	USD
CY2020	us-gaap	Interest Expense InterestExpense	831000000	USD
CY2019	us-gaap	Interest Expense InterestExpense	893000000	USD
CY2021	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-297000000	USD
CY2020	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-145000000	USD
CY2019	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-187000000	USD
CY2021	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	1940000000	USD
CY2020	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	1338000000	USD
CY2019	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	170000000	USD
CY2021	us-gaap	Net Periodic Defined Benefits Expense Reversal Of Expense Excluding Service Cost Component NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent	-212000000	USD
CY2020	us-gaap	Net Periodic Defined Benefits Expense Reversal Of Expense Excluding Service Cost Component NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent	-339000000	USD
CY2019	us-gaap	Net Periodic Defined Benefits Expense Reversal Of Expense Excluding Service Cost Component NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent	-545000000	USD
CY2021	mrk	Other Nonoperating Income Expense Other OtherNonoperatingIncomeExpenseOther	256000000	USD
CY2020	mrk	Other Nonoperating Income Expense Other OtherNonoperatingIncomeExpenseOther	130000000	USD
CY2019	mrk	Other Nonoperating Income Expense Other OtherNonoperatingIncomeExpenseOther	-38000000	USD
CY2021	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	1341000000	USD
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	890000000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-129000000	USD
CY2021	us-gaap	Interest Paid InterestPaid	779000000	USD
CY2020	us-gaap	Interest Paid InterestPaid	822000000	USD
CY2019	us-gaap	Interest Paid InterestPaid	841000000	USD
CY2021	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	2915000000	USD
CY2021	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	1231000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	1506000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2021	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-1446000000	USD
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.104
CY2020	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-965000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.165
CY2019	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-461000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.064
CY2021	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Amount EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionAmount	-75000000	USD
CY2021	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Percent EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionPercent	-0.005
CY2020	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Amount EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionAmount	349000000	USD
CY2020	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Percent EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionPercent	0.060
CY2019	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Amount EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionAmount	323000000	USD
CY2019	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Percent EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionPercent	0.045
CY2021	us-gaap	Income Tax Reconciliation Tax Settlements IncomeTaxReconciliationTaxSettlements	-275000000	USD
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Settlements EffectiveIncomeTaxRateReconciliationTaxSettlements	-0.020
CY2020	us-gaap	Income Tax Reconciliation Tax Settlements IncomeTaxReconciliationTaxSettlements	-13000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Settlements EffectiveIncomeTaxRateReconciliationTaxSettlements	-0.002
CY2019	us-gaap	Income Tax Reconciliation Tax Settlements IncomeTaxReconciliationTaxSettlements	-139000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Settlements EffectiveIncomeTaxRateReconciliationTaxSettlements	-0.019
CY2021	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	81000000	USD
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.006
CY2020	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	108000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.018
CY2019	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	116000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.016
CY2021	mrk	Effective Income Tax Rate Reconciliation Business Combination Three EffectiveIncomeTaxRateReconciliationBusinessCombinationThree	-9000000	USD
CY2021	mrk	Effective Income Tax Rate Reconciliation Business Combination Three Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationThreePercent	-0.001
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination Three EffectiveIncomeTaxRateReconciliationBusinessCombinationThree	559000000	USD
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination Three Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationThreePercent	0.095
CY2019	mrk	Effective Income Tax Rate Reconciliation Business Combination Three EffectiveIncomeTaxRateReconciliationBusinessCombinationThree	0	USD
CY2019	mrk	Effective Income Tax Rate Reconciliation Business Combination Three Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationThreePercent	0
CY2021	mrk	Effective Income Tax Rate Reconciliation Business Combination Four EffectiveIncomeTaxRateReconciliationBusinessCombinationFour	356000000	USD
CY2021	mrk	Effective Income Tax Rate Reconciliation Business Combination Four Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationFourPercent	0.026
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination Four EffectiveIncomeTaxRateReconciliationBusinessCombinationFour	0	USD
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination Four Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationFourPercent	0
CY2019	mrk	Effective Income Tax Rate Reconciliation Business Combination Four EffectiveIncomeTaxRateReconciliationBusinessCombinationFour	0	USD
CY2019	mrk	Effective Income Tax Rate Reconciliation Business Combination Four Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationFourPercent	0
CY2021	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	102000000	USD
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.007
CY2020	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	37000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.006
CY2019	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	115000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.016
CY2021	us-gaap	Income Tax Reconciliation Nondeductible Expense Restructuring Charges IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges	61000000	USD
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Restructuring Charges EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges	0.004
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Restructuring Charges IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges	105000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Restructuring Charges EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges	0.018
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Restructuring Charges IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges	39000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Restructuring Charges EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges	0.005
CY2021	mrk	Income Tax Reconciliation Amortization Of Purchase Accounting Adjustments IncomeTaxReconciliationAmortizationOfPurchaseAccountingAdjustments	8000000	USD
CY2021	mrk	Effective Income Tax Rate Reconciliation Amortization Of Purchase Accounting Adjustments EffectiveIncomeTaxRateReconciliationAmortizationOfPurchaseAccountingAdjustments	0.001
CY2020	mrk	Income Tax Reconciliation Amortization Of Purchase Accounting Adjustments IncomeTaxReconciliationAmortizationOfPurchaseAccountingAdjustments	38000000	USD
CY2020	mrk	Effective Income Tax Rate Reconciliation Amortization Of Purchase Accounting Adjustments EffectiveIncomeTaxRateReconciliationAmortizationOfPurchaseAccountingAdjustments	0.006
CY2019	mrk	Income Tax Reconciliation Amortization Of Purchase Accounting Adjustments IncomeTaxReconciliationAmortizationOfPurchaseAccountingAdjustments	70000000	USD
CY2019	mrk	Effective Income Tax Rate Reconciliation Amortization Of Purchase Accounting Adjustments EffectiveIncomeTaxRateReconciliationAmortizationOfPurchaseAccountingAdjustments	0.010
CY2021	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	2000000	USD
CY2021	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0
CY2020	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	57000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.010
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-12000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	-0.002
CY2021	mrk	Effective Income Tax Rate Reconciliation Business Combination Two EffectiveIncomeTaxRateReconciliationBusinessCombinationTwo	0	USD
CY2021	mrk	Effective Income Tax Rate Reconciliation Business Combination Two Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationTwoPercent	0
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination Two EffectiveIncomeTaxRateReconciliationBusinessCombinationTwo	97000000	USD
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination Two Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationTwoPercent	0.017
CY2019	mrk	Effective Income Tax Rate Reconciliation Business Combination Two EffectiveIncomeTaxRateReconciliationBusinessCombinationTwo	0	USD
CY2019	mrk	Effective Income Tax Rate Reconciliation Business Combination Two Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationTwoPercent	0
CY2021	mrk	Effective Income Tax Rate Reconciliation Business Combination EffectiveIncomeTaxRateReconciliationBusinessCombination	0	USD
CY2021	mrk	Effective Income Tax Rate Reconciliation Business Combination Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationPercent	0
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination EffectiveIncomeTaxRateReconciliationBusinessCombination	0	USD
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationPercent	0
CY2019	mrk	Effective Income Tax Rate Reconciliation Business Combination EffectiveIncomeTaxRateReconciliationBusinessCombination	209000000	USD
CY2019	mrk	Effective Income Tax Rate Reconciliation Business Combination Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationPercent	0.029
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Amount EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Amount	0	USD
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Percent EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent	0
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Amount EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Amount	0	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Percent EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent	0
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Amount EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Amount	117000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Percent EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent	0.016
CY2021	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-37000000	USD
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.002
CY2020	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-47000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.008
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-86000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.012
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1521000000	USD
CY2021	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.110
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1340000000	USD
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.229
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1565000000	USD
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.218
CY2021Q4	us-gaap	Tax Cuts And Jobs Act Of2017 Transition Tax For Accumulated Foreign Earnings Liability TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiability	2600000000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	1854000000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-3814000000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-66000000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	12025000000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	9677000000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	7237000000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	13879000000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	5863000000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	7171000000	USD
CY2021	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	74000000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	893000000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	642000000	USD
CY2021	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	1273000000	USD
CY2020	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	969000000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	1523000000	USD
CY2021	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-13000000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	44000000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-40000000	USD
CY2021	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	1334000000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	1906000000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	2125000000	USD
CY2021	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	240000000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-605000000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-328000000	USD
CY2021	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-77000000	USD
CY2020	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	64000000	USD
CY2019	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-228000000	USD
CY2021	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	24000000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-25000000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-4000000	USD
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	187000000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-566000000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-560000000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1521000000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1340000000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1565000000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Goodwill And Intangible Assets DeferredTaxAssetsGoodwillAndIntangibleAssets	0	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	2933000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Goodwill And Intangible Assets DeferredTaxAssetsGoodwillAndIntangibleAssets	109000000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	1250000000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Inventory DeferredTaxAssetsInventory	119000000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Capitalized Inventory Costs DeferredTaxLiabilitiesDeferredExpenseCapitalizedInventoryCosts	370000000	USD
CY2021Q4	mrk	Deferred Tax Assets Unrecognized Tax Benefits DeferredTaxAssetsUnrecognizedTaxBenefits	75000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Inventory DeferredTaxAssetsInventory	43000000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Capitalized Inventory Costs DeferredTaxLiabilitiesDeferredExpenseCapitalizedInventoryCosts	315000000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	0	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	589000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	0	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	587000000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Equity Method Investments DeferredTaxAssetsEquityMethodInvestments	0	USD
CY2021Q4	mrk	Deferred Tax Liabilities Equity Method Investment DeferredTaxLiabilitiesEquityMethodInvestment	335000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Equity Method Investments DeferredTaxAssetsEquityMethodInvestments	0	USD
CY2020Q4	mrk	Deferred Tax Liabilities Equity Method Investment DeferredTaxLiabilitiesEquityMethodInvestment	175000000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	487000000	USD
CY2021Q4	mrk	Deferred Tax Liabilities Pensions And Other Postretirement Benefit Plans DeferredTaxLiabilitiesPensionsAndOtherPostretirementBenefitPlans	338000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	826000000	USD
CY2020Q4	mrk	Deferred Tax Liabilities Pensions And Other Postretirement Benefit Plans DeferredTaxLiabilitiesPensionsAndOtherPostretirementBenefitPlans	248000000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	301000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	235000000	USD
CY2020Q4	mrk	Deferred Tax Assets Unrecognized Tax Benefits DeferredTaxAssetsUnrecognizedTaxBenefits	117000000	USD
CY2021Q4	mrk	Deferred Tax Assets Operating Loss Carryforwards And Other Tax Credit Carryforwards DeferredTaxAssetsOperatingLossCarryforwardsAndOtherTaxCreditCarryforwards	867000000	USD
CY2020Q4	mrk	Deferred Tax Assets Operating Loss Carryforwards And Other Tax Credit Carryforwards DeferredTaxAssetsOperatingLossCarryforwardsAndOtherTaxCreditCarryforwards	764000000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	434000000	USD
CY2021Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	180000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	743000000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	81000000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	2283000000	USD
CY2021Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	4745000000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	2837000000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	2656000000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	287000000	USD
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Merck & Co., Inc. Stock $mrk

2021 Q4 Form 10-K Financial Statement

#000031015822000003 Filed on February 25, 2022

Income Statement

Balance Sheet

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Facts In Submission

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$MRK Merck & Co., Inc. Stock $mrk

2021 Q4 Form 10-K Financial Statement

#000031015822000003 Filed on February 25, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$MRK
Merck & Co., Inc. Stock $mrk