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

$mrk Overview Financials Valuation SEC Filings Company Website

2020 Form 10-K Financial Statement

#000031015821000004 Filed on February 25, 2021

Income Statement

Concept	2020	2019 Q4	2019
Revenue	$41.52B	$11.87B	$39.12B
YoY Change	6.13%	7.91%	-7.5%
Cost Of Revenue	$13.62B	$2.874B	$12.02B
YoY Change	13.33%	-12.27%	-11.05%
Gross Profit	$27.90B	$8.994B	$27.11B
YoY Change	2.93%	16.47%	-5.84%
Gross Profit Margin	67.2%	75.78%	69.29%
Selling, General & Admin	$8.955B	$2.888B	$9.455B
YoY Change	-5.29%	10.65%	-6.4%
% of Gross Profit	32.1%	32.11%	34.88%
Research & Development	$13.40B	$2.376B	$9.724B
YoY Change	37.77%	15.28%	-0.29%
% of Gross Profit	48.02%	26.42%	35.88%
Depreciation & Amortization	$1.700B	$936.0M	$3.652B
YoY Change	-53.45%	-6.21%	-19.19%
% of Gross Profit	6.09%	10.41%	13.47%
Operating Expenses	$22.35B	$5.264B	$19.18B
YoY Change	16.54%	12.7%	-3.4%
Operating Profit	$5.548B	$3.730B	$7.926B
YoY Change	-30.0%	22.25%	-11.25%
Interest Expense	$831.0M	-$71.00M	$893.0M
YoY Change	-6.94%	-180.68%	15.67%
% of Operating Profit	14.98%	-1.9%	11.27%
Other Income/Expense, Net	$890.0M	$294.0M	-$129.0M
YoY Change	-789.92%	-248.48%	-132.09%
Pretax Income	$5.863B	$2.791B	$7.171B
YoY Change	-18.24%	7.18%	-17.58%
Income Tax	$1.340B	$378.0M	$1.565B
% Of Pretax Income	22.86%	13.54%	21.82%
Net Earnings	$7.067B	$2.356B	$9.843B
YoY Change	-28.2%	28.95%	58.25%
Net Earnings / Revenue	17.02%	19.85%	25.16%
Basic Earnings Per Share	$2.79		$3.84
Diluted Earnings Per Share	$2.78	$920.7K	$3.81
COMMON SHARES
Basic Shares Outstanding	2.530B shares	2.546B shares	2.565B shares
Diluted Shares Outstanding	2.541B shares		2.580B shares

Balance Sheet

Concept	2020	2019 Q4	2019
SHORT-TERM ASSETS
Cash & Short-Term Investments	$8.062B	$10.43B	$10.45B
YoY Change	-22.85%	17.68%	17.89%
Cash & Equivalents	$8.062B	$9.676B	$9.676B
Short-Term Investments	$0.00	$749.0M	$774.0M
Other Short-Term Assets	$5.541B	$4.277B	$4.277B
YoY Change	29.55%	-4.96%	-4.96%
Inventory	$6.310B	$5.978B	$5.978B
Prepaid Expenses
Receivables	$7.851B	$6.778B	$6.778B
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$27.76B	$27.48B	$27.48B
YoY Change	1.02%	6.21%	6.21%
LONG-TERM ASSETS
Property, Plant & Equipment	$17.99B	$14.30B	$16.13B
YoY Change	11.53%	7.57%	21.33%
Goodwill		$18.07B
YoY Change		-1.01%
Intangibles		$14.20B
YoY Change		8.33%
Long-Term Investments	$785.0M	$1.469B	$1.469B
YoY Change	-46.56%	-76.43%	-76.43%
Other Assets	$10.21B	$5.698B	$5.698B
YoY Change	79.2%	-24.57%	-24.57%
Total Long-Term Assets	$63.82B	$56.91B	$56.91B
YoY Change	12.14%	0.27%	0.27%
TOTAL ASSETS
Total Short-Term Assets	$27.76B	$27.48B	$27.48B
Total Long-Term Assets	$63.82B	$56.91B	$56.91B
Total Assets	$91.59B	$84.40B	$84.40B
YoY Change	8.52%	2.13%	2.13%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$4.594B	$3.738B	$3.738B
YoY Change	22.9%	12.66%	12.66%
Accrued Expenses	$13.05B	$12.45B	$12.45B
YoY Change	4.82%	23.63%	23.63%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$6.431B	$1.900B	$3.610B
YoY Change	78.14%	-64.2%	-31.99%
Total Short-Term Liabilities	$27.33B	$22.22B	$22.22B
YoY Change	22.98%	0.06%	0.06%
LONG-TERM LIABILITIES
Long-Term Debt	$25.36B	$22.74B	$22.74B
YoY Change	11.54%	14.79%	14.79%
Other Long-Term Liabilities	$12.48B	$11.97B	$11.97B
YoY Change	4.28%	-0.59%	-0.59%
Total Long-Term Liabilities	$37.84B	$34.71B	$34.71B
YoY Change	9.04%	8.98%	8.98%
TOTAL LIABILITIES
Total Short-Term Liabilities	$27.33B	$22.22B	$22.22B
Total Long-Term Liabilities	$37.84B	$34.71B	$34.71B
Total Liabilities	$66.27B	$56.93B	$58.49B
YoY Change	13.3%	5.32%	4.57%
SHAREHOLDERS EQUITY
Retained Earnings		$46.60B
YoY Change		9.45%
Common Stock		$41.45B
YoY Change		2.1%
Preferred Stock
YoY Change
Treasury Stock (at cost)		$55.95B
YoY Change		9.86%
Treasury Stock Shares		1.038B shares
Shareholders Equity	$25.32B	$25.91B	$25.91B
YoY Change
Total Liabilities & Shareholders Equity	$91.59B	$84.40B	$84.40B
YoY Change	8.52%	2.13%	2.13%

Cashflow Statement

Concept	2020	2019 Q4	2019
OPERATING ACTIVITIES
Net Income	$7.067B	$2.356B	$9.843B
YoY Change	-28.2%	28.95%	58.25%
Depreciation, Depletion And Amortization	$1.700B	$936.0M	$3.652B
YoY Change	-53.45%	-6.21%	-19.19%
Cash From Operating Activities	$10.25B	$4.794B	$13.44B
YoY Change	-23.71%	33.46%	23.05%
INVESTING ACTIVITIES
Capital Expenditures	-$4.684B	-$1.137B	-$3.473B
YoY Change	34.87%	22.39%	32.81%
Acquisitions	$1.365B		$294.0M
YoY Change	364.29%		-31.79%
Other Investing Activities	-$125.0M	$374.0M	-$374.0M
YoY Change	-66.58%	-87.96%	266.67%
Cash From Investing Activities	-$9.443B	-$763.0M	-$2.629B
YoY Change	259.19%	-135.03%	-160.94%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net	$1.281B		$4.780B
YoY Change	-73.2%		-47.42%
Debt Paid & Issued, Net	$1.957B		$0.00
YoY Change			-100.0%
Cash From Financing Activities	-$2.832B	-2.011B	-$8.861B
YoY Change	-68.04%	-63.87%	-32.67%
NET CHANGE
Cash From Operating Activities	$10.25B	4.794B	$13.44B
Cash From Investing Activities	-$9.443B	-763.0M	-$2.629B
Cash From Financing Activities	-$2.832B	-2.011B	-$8.861B
Net Change In Cash	-$1.769B	2.020B	$1.967B
YoY Change	-189.93%	890.2%	5.13%
FREE CASH FLOW
Cash From Operating Activities	$10.25B	$4.794B	$13.44B
Capital Expenditures	-$4.684B	-$1.137B	-$3.473B
Free Cash Flow	$14.94B	$5.931B	$16.91B
YoY Change	-11.68%	31.19%	24.94%

Facts In Submission

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CY2020	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
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CY2020	dei	Entity File Number EntityFileNumber	1-6571
CY2020	dei	Entity Registrant Name EntityRegistrantName	Merck & Co., Inc.
CY2020	dei	Entity Address Address Line1 EntityAddressAddressLine1	2000 Galloping Hill Road
CY2020	dei	Entity Address City Or Town EntityAddressCityOrTown	Kenilworth
CY2020	dei	Entity Address State Or Province EntityAddressStateOrProvince	NJ
CY2020	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	07033
CY2020	dei	City Area Code CityAreaCode	908
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CY2020	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	NJ
CY2020	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	22-1918501
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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
CY2018	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-205000000	USD
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CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	1967000000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	1871000000	USD
CY2019Q4	us-gaap	Restricted Cash RestrictedCash	258000000	USD
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CY2020Q4	us-gaap	Restricted Cash RestrictedCash	103000000	USD
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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
CY2020	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, primarily administered at physician offices. 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 in the first quarter of 2020.</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 an Alliances segment that primarily included activity from the Company’s relationship with AstraZeneca LP related to sales of Nexium and Prilosec, which concluded in 2018. </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%">Planned Spin-Off of Women’s Health, Biosimilars and Established Brands into a New Company </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%">In February 2020, Merck announced its intention to spin-off 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 as tax-free to the Company and its shareholders for U.S. federal income tax purposes. The established brands included in the transaction consist of dermatology, non-opioid pain management, respiratory, and select cardiovascular products including </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Zetia</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> and </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Vytorin</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, as well as the rest of Merck’s diversified brands franchise. Merck’s existing research pipeline programs will continue to be owned and developed within Merck as planned. Organon will have development capabilities initially focused on late-stage development and life-cycle management and is expected over time to develop research capabilities in selected therapeutic areas. The spin-off is expected to be completed late in the second quarter of 2021, subject to market and certain other conditions. Subsequent to the spin-off, the historical results of the women’s health, biosimilars and established brands businesses will be reflected as discontinued operations in the Company’s consolidated financial statements.</span></div>
CY2020	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	2	segment
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CY2018	us-gaap	Depreciation Depreciation	1400000000	USD
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CY2018	us-gaap	Advertising Expense AdvertisingExpense	2100000000	USD
CY2019Q4	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	30666000000	USD
CY2020	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 United States (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>
CY2020	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.
CY2020Q4	us-gaap	Restructuring And Related Cost Expected Cost1 RestructuringAndRelatedCostExpectedCost1	3000000000.0	USD
CY2020	mrk	Estimate Of Cumulative Pre Tax Costs That Will Result In Cash Outlays EstimateOfCumulativePreTaxCostsThatWillResultInCashOutlays	0.70
CY2020	mrk	Estimate Of Cumulative Pre Tax Costs That Will Be Noncash EstimateOfCumulativePreTaxCostsThatWillBeNoncash	0.30
CY2020	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	883000000	USD
CY2019	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	927000000	USD
CY2018	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	658000000	USD
CY2020Q4	us-gaap	Restructuring And Related Cost Cost Incurred To Date1 RestructuringAndRelatedCostCostIncurredToDate1	1800000000	USD
CY2020	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	883000000	USD
CY2019	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	927000000	USD
CY2018	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	658000000	USD
CY2018Q4	us-gaap	Restructuring Reserve RestructuringReserve	534000000	USD
CY2019	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	927000000	USD
CY2019	us-gaap	Payments For Restructuring PaymentsForRestructuring	461000000	USD
CY2019	mrk	Restructuring Reserve Noncash Activity RestructuringReserveNoncashActivity	241000000	USD
CY2019Q4	us-gaap	Restructuring Reserve RestructuringReserve	759000000	USD
CY2020	us-gaap	Restructuring And Related Cost Incurred Cost RestructuringAndRelatedCostIncurredCost	883000000	USD
CY2020	us-gaap	Payments For Restructuring PaymentsForRestructuring	809000000	USD
CY2020	mrk	Restructuring Reserve Noncash Activity RestructuringReserveNoncashActivity	230000000	USD
CY2020Q4	us-gaap	Restructuring Reserve RestructuringReserve	603000000	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
CY2019Q4	us-gaap	Derivative Assets DerivativeAssets	288000000	USD
CY2019Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	97000000	USD
CY2020Q4	us-gaap	Derivative Assets DerivativeAssets	182000000	USD
CY2020Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	525000000	USD
CY2019Q4	us-gaap	Derivative Assets DerivativeAssets	288000000	USD
CY2019Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	97000000	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
CY2019Q4	us-gaap	Derivative Asset Not Offset Policy Election Deduction DerivativeAssetNotOffsetPolicyElectionDeduction	84000000	USD
CY2019Q4	us-gaap	Derivative Liability Not Offset Policy Election Deduction DerivativeLiabilityNotOffsetPolicyElectionDeduction	84000000	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
CY2019Q4	us-gaap	Derivative Collateral Obligation To Return Cash DerivativeCollateralObligationToReturnCash	34000000	USD
CY2019Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	0	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
CY2019Q4	us-gaap	Derivative Asset Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeAssetFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	170000000	USD
CY2019Q4	us-gaap	Derivative Liability Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeLiabilityFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	13000000	USD
CY2020	us-gaap	Revenues Revenues	47994000000	USD
CY2019	us-gaap	Revenues Revenues	46840000000	USD
CY2018	us-gaap	Revenues Revenues	42294000000	USD
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	886000000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-139000000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	402000000	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
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-361000000	USD
CY2020	us-gaap	Derivative Instruments Gain Loss Reclassification From Accumulated Oci To Income Estimated Net Amount To Be Transferred DerivativeInstrumentsGainLossReclassificationFromAccumulatedOCIToIncomeEstimatedNetAmountToBeTransferred	-331000000	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
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1768000000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	17000000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	0	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1785000000	USD
CY2020Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	1787000000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	838000000	USD
CY2020Q4	mrk	Debt Securitiesand Equity Securities Fvni DebtSecuritiesandEquitySecuritiesFVNI	1876000000	USD
CY2019Q4	mrk	Debt Securitiesand Equity Securities Fvni DebtSecuritiesandEquitySecuritiesFVNI	2623000000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	163000000	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	160000000	USD
CY2020Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	586000000	USD
CY2019Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	420000000	USD
CY2020	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	62000000	USD
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	20000000	USD
CY2020	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	3000000	USD
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	13000000	USD
CY2020Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentCumulativeAmount	169000000	USD
CY2020Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Cumulative Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount	24000000	USD
CY2019Q4	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	767000000	USD
CY2018Q4	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	788000000	USD
CY2020	us-gaap	Business Combination Consideration Transferred Liabilities Incurred BusinessCombinationConsiderationTransferredLiabilitiesIncurred	97000000	USD
CY2019	us-gaap	Business Combination Consideration Transferred Liabilities Incurred BusinessCombinationConsiderationTransferredLiabilitiesIncurred	0	USD
CY2020	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	83000000	USD
CY2019	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	64000000	USD
CY2020	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements	106000000	USD
CY2019	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements	85000000	USD
CY2020Q4	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	841000000	USD
CY2019Q4	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	767000000	USD
CY2020Q4	us-gaap	Business Combination Contingent Consideration Liability Current BusinessCombinationContingentConsiderationLiabilityCurrent	148000000	USD
CY2020Q4	us-gaap	Debt Instrument Fair Value DebtInstrumentFairValue	36000000000.0	USD
CY2020Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	31800000000	USD
CY2019Q4	us-gaap	Debt Instrument Fair Value DebtInstrumentFairValue	28800000000	USD
CY2019Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	26300000000	USD
CY2020Q4	us-gaap	Accounts Receivable Sale AccountsReceivableSale	2300000000	USD
CY2019Q4	us-gaap	Accounts Receivable Sale AccountsReceivableSale	2700000000	USD
CY2020Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	102000000	USD
CY2019Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	256000000	USD
CY2020Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	36000000	USD
CY2019Q4	us-gaap	Derivative Collateral Obligation To Return Cash DerivativeCollateralObligationToReturnCash	34000000	USD
CY2020Q4	us-gaap	Inventory Finished Goods InventoryFinishedGoods	1963000000	USD
CY2019Q4	us-gaap	Inventory Finished Goods InventoryFinishedGoods	1772000000	USD
CY2020Q4	us-gaap	Inventory Work In Process And Raw Materials InventoryWorkInProcessAndRawMaterials	6420000000	USD
CY2019Q4	us-gaap	Inventory Work In Process And Raw Materials InventoryWorkInProcessAndRawMaterials	5650000000	USD
CY2020Q4	us-gaap	Other Inventory Supplies OtherInventorySupplies	206000000	USD
CY2019Q4	us-gaap	Other Inventory Supplies OtherInventorySupplies	207000000	USD
CY2020Q4	us-gaap	Inventory Gross InventoryGross	8589000000	USD
CY2019Q4	us-gaap	Inventory Gross InventoryGross	7629000000	USD
CY2020Q4	us-gaap	Inventory Lifo Reserve InventoryLIFOReserve	82000000	USD
CY2019Q4	us-gaap	Inventory Lifo Reserve InventoryLIFOReserve	171000000	USD
CY2020Q4	mrk	Inventory Net And Inventory Noncurrent InventoryNetAndInventoryNoncurrent	8507000000	USD
CY2019Q4	mrk	Inventory Net And Inventory Noncurrent InventoryNetAndInventoryNoncurrent	7458000000	USD
CY2020Q4	us-gaap	Inventory Net InventoryNet	6310000000	USD
CY2019Q4	us-gaap	Inventory Net InventoryNet	5978000000	USD
CY2020Q4	us-gaap	Inventory Noncurrent InventoryNoncurrent	2197000000	USD
CY2019Q4	us-gaap	Inventory Noncurrent InventoryNoncurrent	1480000000	USD
CY2020Q4	us-gaap	Lifo Inventory Amount LIFOInventoryAmount	2900000000	USD
CY2019Q4	us-gaap	Lifo Inventory Amount LIFOInventoryAmount	2600000000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	18253000000	USD
CY2019	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	1341000000	USD
CY2019	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	162000000	USD
CY2019	us-gaap	Goodwill Other Increase Decrease GoodwillOtherIncreaseDecrease	-7000000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	19425000000	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	20238000000	USD
CY2019Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	531000000	USD
CY2020Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	531000000	USD
CY2020Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	57597000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	42993000000	USD
CY2020Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	14604000000	USD
CY2019Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	55324000000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	41128000000	USD
CY2019Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	14196000000	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
CY2018	us-gaap	Impairment Of Intangible Assets Indefinitelived Excluding Goodwill ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill	152000000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1900000000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2000000000.0	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3100000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	1500000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	1500000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	1400000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	1300000000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	1200000000	USD
CY2020Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	2300000000	USD
CY2019Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	1900000000	USD
CY2020Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	25360000000	USD
CY2019Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	22736000000	USD
CY2020Q2	us-gaap	Debt Instrument Face Amount DebtInstrumentFaceAmount	4500000000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	2300000000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	2300000000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	1700000000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	1400000000	USD
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	2500000000	USD
CY2020Q4	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	6000000000.0	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	346000000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	339000000	USD
CY2018	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	322000000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	340000000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	281000000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	495000000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	129000000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	1725000000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	1073000000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	300000000	USD
CY2019Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	236000000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	1362000000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	768000000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	1662000000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	1004000000	USD
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P8Y
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P7Y4M24D
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.028
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.032
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	336000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	277000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	252000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	187000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	162000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	665000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	1879000000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	217000000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	1662000000	USD
CY2020Q4	mrk	Lessee Operating Lease Lease Notyet Commenced Amount LesseeOperatingLeaseLeaseNotyetCommencedAmount	475000000	USD
CY2020Q4	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	67000000	USD
CY2020	mrk	Term For Paying Off Environmental Liabilities TermForPayingOffEnvironmentalLiabilities	P15Y
CY2020	us-gaap	Environmental Exit Costs Reasonably Possible Additional Loss EnvironmentalExitCostsReasonablyPossibleAdditionalLoss	65000000	USD
CY2020Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	6500000000	shares
CY2020Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	100000000	shares
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Award Requisite Service Period1 ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1	P3Y
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Award Requisite Service Period1 ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1	P3Y
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Award Requisite Service Period1 ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1	P3Y
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	475000000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	417000000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	348000000	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
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	55000000	USD
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
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	58.15
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
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	8.26
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
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.034
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
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.029
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
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.191
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
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P6Y1M6D
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	17868000	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	59.88
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod	3564000	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	77.67
CY2020	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	1685000	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	52.73
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	301000	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	67.73
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
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P6Y3M7D
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	353000000	USD
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	13141000	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	58.30
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P5Y1M17D
CY2020Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	309000000	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
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	348000000	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
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	29000000	USD
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	89000000	USD
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	361000000	USD
CY2018	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	591000000	USD
CY2020Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	678000000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P1Y10M24D
CY2020Q4	us-gaap	Defined Benefit Plan Accumulated Benefit Obligation DefinedBenefitPlanAccumulatedBenefitObligation	26400000000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Accumulated Benefit Obligation DefinedBenefitPlanAccumulatedBenefitObligation	22800000000	USD
CY2020	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	166000000	USD
CY2019	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	149000000	USD
CY2018	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	136000000	USD
CY2020	us-gaap	Investment Income Interest InvestmentIncomeInterest	59000000	USD
CY2019	us-gaap	Investment Income Interest InvestmentIncomeInterest	274000000	USD
CY2018	us-gaap	Investment Income Interest InvestmentIncomeInterest	343000000	USD
CY2020	us-gaap	Interest Expense InterestExpense	831000000	USD
CY2019	us-gaap	Interest Expense InterestExpense	893000000	USD
CY2018	us-gaap	Interest Expense InterestExpense	772000000	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
CY2018	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-145000000	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
CY2018	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	324000000	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
CY2018	us-gaap	Net Periodic Defined Benefits Expense Reversal Of Expense Excluding Service Cost Component NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent	-512000000	USD
CY2020	mrk	Other Nonoperating Income Expense Other OtherNonoperatingIncomeExpenseOther	126000000	USD
CY2019	mrk	Other Nonoperating Income Expense Other OtherNonoperatingIncomeExpenseOther	-48000000	USD
CY2018	mrk	Other Nonoperating Income Expense Other OtherNonoperatingIncomeExpenseOther	140000000	USD
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	886000000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-139000000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	402000000	USD
CY2018	us-gaap	Impairment Of Long Lived Assets To Be Disposed Of ImpairmentOfLongLivedAssetsToBeDisposedOf	41000000	USD
CY2020	us-gaap	Interest Paid InterestPaid	822000000	USD
CY2019	us-gaap	Interest Paid InterestPaid	841000000	USD
CY2018	us-gaap	Interest Paid InterestPaid	777000000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	1846000000	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	2408000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	1827000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2020	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-1242000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.141
CY2019	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-1020000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.089
CY2018	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-245000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.028
CY2020	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Amount EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionAmount	364000000	USD
CY2020	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Percent EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionPercent	0.041
CY2019	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Amount EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionAmount	336000000	USD
CY2019	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Percent EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionPercent	0.029
CY2018	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Amount EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionAmount	-25000000	USD
CY2018	mrk	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income Foreign Derived Intangible Income Deduction Percent EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncomeForeignDerivedIntangibleIncomeDeductionPercent	-0.003
CY2020	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	110000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.013
CY2019	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	118000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.010
CY2018	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	96000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.011
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	-403000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Settlements EffectiveIncomeTaxRateReconciliationTaxSettlements	-0.035
CY2018	us-gaap	Income Tax Reconciliation Tax Settlements IncomeTaxReconciliationTaxSettlements	-22000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Settlements EffectiveIncomeTaxRateReconciliationTaxSettlements	-0.003
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination Two EffectiveIncomeTaxRateReconciliationBusinessCombinationTwo	559000000	USD
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination Two Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationTwoPercent	0.063
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
CY2018	mrk	Effective Income Tax Rate Reconciliation Business Combination Two EffectiveIncomeTaxRateReconciliationBusinessCombinationTwo	0	USD
CY2018	mrk	Effective Income Tax Rate Reconciliation Business Combination Two Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationTwoPercent	0
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	0.012
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	0.003
CY2019	mrk	Income Tax Reconciliation Amortization Of Purchase Accounting Adjustments IncomeTaxReconciliationAmortizationOfPurchaseAccountingAdjustments	95000000	USD
CY2019	mrk	Effective Income Tax Rate Reconciliation Amortization Of Purchase Accounting Adjustments EffectiveIncomeTaxRateReconciliationAmortizationOfPurchaseAccountingAdjustments	0.008
CY2018	mrk	Income Tax Reconciliation Amortization Of Purchase Accounting Adjustments IncomeTaxReconciliationAmortizationOfPurchaseAccountingAdjustments	267000000	USD
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Restructuring Charges IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges	56000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Restructuring Charges EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges	0.006
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination Three EffectiveIncomeTaxRateReconciliationBusinessCombinationThree	97000000	USD
CY2020	mrk	Effective Income Tax Rate Reconciliation Business Combination Three Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationThreePercent	0.011
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
CY2018	mrk	Effective Income Tax Rate Reconciliation Business Combination Three EffectiveIncomeTaxRateReconciliationBusinessCombinationThree	0	USD
CY2018	mrk	Effective Income Tax Rate Reconciliation Business Combination Three Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationThreePercent	0
CY2020	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	67000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.008
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-2000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	201000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.023
CY2020	mrk	Income Tax Reconciliation Amortization Of Purchase Accounting Adjustments IncomeTaxReconciliationAmortizationOfPurchaseAccountingAdjustments	46000000	USD
CY2020	mrk	Effective Income Tax Rate Reconciliation Amortization Of Purchase Accounting Adjustments EffectiveIncomeTaxRateReconciliationAmortizationOfPurchaseAccountingAdjustments	0.005
CY2018	mrk	Effective Income Tax Rate Reconciliation Amortization Of Purchase Accounting Adjustments EffectiveIncomeTaxRateReconciliationAmortizationOfPurchaseAccountingAdjustments	0.031
CY2020	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	42000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.005
CY2019	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	113000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.010
CY2018	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	269000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.031
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	0.018
CY2018	mrk	Effective Income Tax Rate Reconciliation Business Combination EffectiveIncomeTaxRateReconciliationBusinessCombination	0	USD
CY2018	mrk	Effective Income Tax Rate Reconciliation Business Combination Percent EffectiveIncomeTaxRateReconciliationBusinessCombinationPercent	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	0.010
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Amount EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Amount	289000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Cuts And Jobs Act Of2017 Percent EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017Percent	0.033
CY2020	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-52000000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.005
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-87000000	USD
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.007
CY2018	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-13000000	USD
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.001
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1709000000	USD
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.194
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1687000000	USD
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.147
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2508000000	USD
CY2018	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.288
CY2020Q4	us-gaap	Tax Cuts And Jobs Act Of2017 Transition Tax For Accumulated Foreign Earnings Liability TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsLiability	3000000000.0	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-3492000000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	439000000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	3717000000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	12283000000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	11025000000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	4984000000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	8791000000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	11464000000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	8701000000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	962000000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	514000000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	536000000	USD
CY2020	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	1362000000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	1806000000	USD
CY2018	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	2281000000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	53000000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-77000000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	200000000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	2377000000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	2243000000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	3017000000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-605000000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-330000000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-402000000	USD
CY2020	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-40000000	USD
CY2019	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-240000000	USD
CY2018	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-64000000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-23000000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	14000000	USD
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-43000000	USD
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2020 Form 10-K Financial Statement

#000031015821000004 Filed on February 25, 2021

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

2020 Form 10-K Financial Statement

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Merck & Co., Inc. Stock $mrk