Merck & Co. (MRK) 10-Q 5 Nov 21 2021 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 31, 2021
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	1-6571
Entity Registrant Name	Merck & Co., Inc.
Entity Incorporation, State or Country Code	NJ
Entity Tax Identification Number	22-1918501
Entity Address, Address Line One	2000 Galloping Hill Road
Entity Address, City or Town	Kenilworth
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	07033
City Area Code	(908)
Local Phone Number	740-4000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		2,525,943,936
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000310158
Current Fiscal Year End Date	--12-31
Common Stock ($0.50 par value)
Entity Information [Line Items]
Title of 12(b) Security	Common Stock ($0.50 par value)
Trading Symbol	MRK
Security Exchange Name	NYSE
0.500% Notes due 2024
Entity Information [Line Items]
Title of 12(b) Security	0.500% Notes due 2024
Trading Symbol	MRK 24
Security Exchange Name	NYSE
1.875% Notes due 2026
Entity Information [Line Items]
Title of 12(b) Security	1.875% Notes due 2026
Trading Symbol	MRK/26
Security Exchange Name	NYSE
2.500% Notes due 2034
Entity Information [Line Items]
Title of 12(b) Security	2.500% Notes due 2034
Trading Symbol	MRK/34
Security Exchange Name	NYSE
1.375% Notes due 2036
Entity Information [Line Items]
Title of 12(b) Security	1.375% Notes due 2036
Trading Symbol	MRK 36A
Security Exchange Name	NYSE

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENT OF INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Sales	$ 13,154	$ 10,929	$ 35,183	$ 30,570
Costs, Expenses and Other
Cost of sales	3,450	3,013	9,752	8,589
Selling, general and administrative	2,336	2,060	6,804	6,336
Research and development	2,445	3,349	9,177	7,609
Restructuring costs	107	113	487	265
Other (income) expense, net	(450)	(312)	(1,007)	(637)
Total Costs, Expenses and Other	7,888	8,223	25,213	22,162
Income from Continuing Operations Before Taxes	5,266	2,706	9,970	8,408
Taxes on Income from Continuing Operations	695	380	1,436	1,271
Net Income from Continuing Operations	4,571	2,326	8,534	7,137
Less: Net Income Attributable to Noncontrolling Interests	4	2	9	1
Net Income from Continuing Operations Attributable to Merck & Co., Inc.	4,567	2,324	8,525	7,136
Income from Discontinued Operations, Net of Taxes and Amounts Attributable to Noncontrolling Interests	0	617	766	2,025
Net Income Attributable to Merck & Co. Inc.	$ 4,567	$ 2,941	$ 9,291	$ 9,161
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders:
Income from Continuing Operations (in dollars per share)	$ 1.81	$ 0.92	$ 3.37	$ 2.82
Income from Discontinued Operations (in dollars per share)	0	0.24	0.30	0.80
Net Income (in dollars per share)	1.81	1.16	3.67	3.62
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders:
Income from Continuing Operations (in dollars per share)	1.80	0.92	3.36	2.81
Income from Discontinued Operations (in dollars per share)	0	0.24	0.30	0.80
Net Income (in dollars per share)	$ 1.80	$ 1.16	$ 3.66	$ 3.61

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net Income Attributable to Merck & Co., Inc.	$ 4,567	$ 2,941	$ 9,291	$ 9,161
Other Comprehensive Income (Loss) Net of Taxes:
Net unrealized gain (loss) on derivatives, net of reclassifications	84	(137)	324	(153)
Net unrealized loss on investments, net of reclassifications	0	0	0	(18)
Benefit plan net gain and prior service credit, net of amortization	38	62	1,522	161
Cumulative translation adjustment	(84)	85	(251)	(180)
Other comprehensive income (loss), net of taxes	38	10	1,595	(190)
Comprehensive Income Attributable to Merck & Co., Inc.	$ 4,605	$ 2,951	$ 10,886	$ 8,971

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEET - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Current Assets
Cash and cash equivalents	$ 10,016	$ 8,050
Accounts receivable (net of allowance for doubtful accounts of $69 in 2021 and $67 in 2020)	8,571	6,803
Inventories (excludes inventories of $2,373 in 2021 and $2,070 in 2020 classified in Other assets - see Note 7)	5,603	5,554
Other current assets	6,868	4,674
Current assets of discontinued operations	0	2,683
Total current assets	31,058	27,764
Investments	435	785
Property, Plant and Equipment, at cost, net of accumulated depreciation of $18,155 in 2021 and $18,162 in 2020	18,565	17,000
Goodwill	18,862	18,882
Other Intangibles, Net	13,384	14,101
Other Assets	11,190	9,881
Noncurrent Assets of Discontinued Operations	0	3,175
Total Assets	93,494	91,588
Current Liabilities
Loans payable and current portion of long-term debt	3,534	6,431
Trade accounts payable	3,366	4,327
Accrued and other current liabilities	14,214	12,212
Income taxes payable	954	1,597
Dividends payable	1,660	1,674
Current liabilities of discontinued operations	0	1,086
Total current liabilities	23,728	27,327
Long-Term Debt	22,907	25,360
Deferred Income Taxes	1,527	1,005
Other Noncurrent Liabilities	9,469	12,306
Noncurrent Liabilities of Discontinued Operations	0	186
Merck & Co., Inc. Stockholders’ Equity
Common stock, $0.50 par value Authorized - 6,500,000,000 shares Issued - 3,577,103,522 shares in 2021 and 2020	1,788	1,788
Other paid-in capital	44,149	39,588
Retained earnings	51,691	47,362
Accumulated other comprehensive loss	(4,590)	(6,634)
Stockholders' equity before deduction for treasury stock	93,038	82,104
Less treasury stock, at cost: 1,051,780,149 shares in 2021 and 1,046,877,695 shares in 2020	57,244	56,787
Total Merck & Co., Inc. stockholders’ equity	35,794	25,317
Noncontrolling Interests	69	87
Total equity	35,863	25,404
Liabilities and Equity	$ 93,494	$ 91,588

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEET (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 69	$ 67
Inventories classified in Other assets	2,373	2,070
Accumulated depreciation	$ 18,155	$ 18,162
Common stock, par value (in dollars per share)	$ 0.50	$ 0.50
Common stock, authorized (shares)	6,500,000,000	6,500,000,000
Common stock, issued (in shares)	3,577,103,522	3,577,103,522
Treasury stock (in shares)	1,051,780,149	1,046,877,695

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash Flows from Operating Activities
Net income from continuing operations	$ 8,534	$ 7,137
Adjustments to reconcile net income from continuing operations to net cash provided by operating activities:
Amortization	1,231	1,393
Depreciation	1,148	1,210
Intangible asset impairment charges	0	35
Income from investments in equity securities, net	(1,535)	(964)
Charge for the acquisition of Pandion Therapeutics, Inc.	1,556	0
Deferred income taxes	28	32
Share-based compensation	360	329
Other	499	519
Net changes in assets and liabilities	(3,794)	(5,484)
Net Cash Provided by Operating Activities from Continuing Operations	8,027	4,207
Cash Flows from Investing Activities
Capital expenditures	(3,240)	(2,998)
Purchases of securities and other investments	(1)	(78)
Proceeds from sales of securities and other investments	497	1,894
Acquisition of Pandion Therapeutics, Inc. net of cash acquired	(1,554)	0
Acquisition of ArQule, Inc., net of cash acquired	0	(2,545)
Other acquisitions, net of cash acquired	(89)	(907)
Other	15	138
Net Cash Used in Investing Activities from Continuing Operations	(4,372)	(4,496)
Cash Flows from Financing Activities
Net change in short-term borrowings	(3,983)	(311)
Payments on debt	(1,153)	(1,954)
Distribution from Organon & Co.	9,000	0
Proceeds from issuance of debt	0	4,419
Purchases of treasury stock	(822)	(1,281)
Dividends paid to stockholders	(4,967)	(4,673)
Proceeds from exercise of stock options	68	68
Other	(253)	(472)
Net Cash Used in Financing Activities from Continuing Operations	(2,110)	(4,204)
Discontinued Operations
Net cash provided by operating activities	1,051	2,040
Net cash used in investing activities	(134)	(169)
Net cash used in financing activities	(504)	0
Net Cash Flows Provided by Discontinued Operations	413	1,871
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	(65)	89
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	1,893	(2,533)
Cash, Cash Equivalents and Restricted Cash at Beginning of Year (includes restricted cash of $103 at January 1, 2021 included in Other Assets)	8,153	9,934
Cash, Cash Equivalents and Restricted Cash at End of Period (includes restricted cash of $30 at September 30, 2021 included in Other Assets)	$ 10,046	$ 7,401

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Statement of Cash Flows [Abstract]
Restricted cash	$ 30	$ 103

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements of Merck & Co., Inc. (Merck or the Company) have been prepared pursuant to the rules and regulations for reporting on Form 10-Q. Accordingly, certain information and disclosures required by accounting principles generally accepted in the United States (U.S.) (GAAP) for complete consolidated financial statements are not included herein. These interim statements should be read in conjunction with the audited financial statements and notes thereto included in Merck’s Form 10-K filed on February 25, 2021. The results of operations of any interim period are not necessarily indicative of the results of operations for the full year. In the Company’s opinion, all adjustments necessary for a fair statement of these interim statements have been included and are of a normal and recurring nature. Reclassifications — Certain reclassifications have been made to prior year amounts to conform to the current year presentation. Spin-Off of Organon & Co. 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 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 women’s health, biosimilars and established brands 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 2). Recently Adopted Accounting Standards In December 2019, the Financial Accounting Standards Board (FASB) issued amended guidance on the accounting and reporting of income taxes. The guidance is intended to simplify the accounting for income taxes by removing exceptions related to certain intraperiod tax allocations and deferred tax liabilities, clarifying guidance primarily related to evaluating the step-up tax basis for goodwill in a business combination, and reflecting enacted changes in tax laws or rates in the annual effective tax rate. The Company adopted the new guidance effective January 1, 2021. There was no impact to the Company’s consolidated financial statements upon adoption. In January 2020, the FASB issued new guidance intended to clarify certain interactions between accounting standards related to equity securities, equity method investments and certain derivatives. The guidance addresses accounting for the transition into and out of the equity method of accounting and measuring certain purchased options and forward contracts to acquire investments. The Company adopted the new guidance effective January 1, 2021. There was no impact to the Company’s consolidated financial statements upon adoption. Recently Issued Accounting Standards Not Yet Adopted In March 2020, the FASB issued optional guidance to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting and subsequently issued clarifying amendments. The guidance provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions that reference the London Interbank Offered Rate (LIBOR) or another reference rate expected to be discontinued because of reference rate reform. The optional guidance is effective upon issuance and can be applied on a prospective basis at any time between January 1, 2020 through December 31, 2022. The Company is currently evaluating the impact of adoption on its consolidated financial statements. In August 2020, the FASB issued amended guidance on the accounting for convertible instruments and contracts in an entity’s own equity. The guidance removes the separation model for convertible debt instruments and preferred stock, amends requirements for conversion options to be classified in equity as well as amends diluted earnings per share (EPS) calculations for certain convertible debt instruments. The amended guidance is effective for interim and annual periods in 2022. Early adoption is permitted. The application of the amendments in the new guidance are to be applied either on a modified retrospective or a retrospective basis. The Company is currently evaluating the impact of adoption on its consolidated financial statements.

Spin-Off of Organon & Co.

Spin-Off of Organon & Co.	9 Months Ended
	Sep. 30, 2021
Discontinued Operations and Disposal Groups [Abstract]
Spin-Off of Organon & Co.	Spin-Off of Organon & Co. On June 2, 2021, Merck completed the spin-off of Organon through a distribution of Organon’s publicly traded stock to Company shareholders. In connection with the spin-off, each Merck shareholder received one tenth of a share of Organon’s common stock for each share of Merck common stock held by such shareholder. The distribution is expected to qualify as tax free to Merck and its shareholders for U.S. federal income tax purposes. Indebtedness of $9.5 billion principal amount, consisting of term loans and senior notes, was issued in 2021 in connection with the spin-off and assumed by Organon. Merck is no longer the obligor of any Organon debt or financing arrangements. Cash proceeds of $9.0 billion were distributed by Organon to Merck in connection with the spin-off. Also in connection with the spin-off, Merck and Organon entered into a separation and distribution agreement and also entered into various other agreements to effect the spin-off and provide a framework for the relationship between Merck and Organon after the spin-off, including a transition services agreement (TSA), manufacturing and supply agreements (MSAs), trademark license agreements, intellectual property license agreements, an employee matters agreement, a tax matters agreement and certain other commercial agreements. Under the TSA, Merck will provide Organon various services and, similarly, Organon will provide Merck various services. The provision of services under the TSA agreement generally will terminate within 25 months following the spin-off. Merck and Organon also entered into a series of interim operating agreements pursuant to which in various jurisdictions where Merck held licenses, permits and other rights in connection with marketing, import and/or distribution of Organon products prior to the separation, Merck will continue to market, import and distribute such products until such time as the relevant licenses and permits are transferred to Organon. Under such interim operating agreements and in accordance with the separation and distribution agreement, Merck will continue operations in the affected markets on behalf of Organon, with Organon receiving all of the economic benefits and burdens of such activities. Additionally, Merck and Organon entered into a number of MSAs pursuant to which Merck will (a) manufacture and supply certain active pharmaceutical ingredients for Organon, (b) toll manufacture and supply certain formulated pharmaceutical products for Organon, and (c) package and label certain finished pharmaceutical products for Organon. Similarly, Organon and Merck entered into a number of MSAs pursuant to which Organon will (a) manufacture and supply certain formulated pharmaceutical products for Merck, and (b) package and label certain finished pharmaceutical products for Merck. The terms of the MSAs range in initial duration from four years to ten years. Amounts included in the condensed consolidated statement of income for the above agreements were immaterial in the third quarter and first nine months of 2021. The amount due from Organon under the above agreements was $1.4 billion at September 30, 2021 and is reflected in Other current assets . The amount due to Organon under these agreements was $930 million at September 30, 2021 and is included in A ccrued and other current liabilities . The results of the women’s health, biosimilars and established brands businesses (previously included in the Pharmaceutical segment) that were contributed to Organon in the spin-off, as well as interest expense related to the debt issuance in 2021, have been reflected as discontinued operations in the Company’s condensed consolidated statement of income as Income from Discontinued Operations, Net of Taxes and Amounts Attributable to Noncontrolling Interests through June 2, 2021, the date of the spin-off. Prior periods have been recast to reflect this presentation. As a result of the spin-off of Organon, Merck incurred separation costs of $556 million in the nine months ended September 30, 2021, and $193 million and $483 million in the three and nine months ended September 30, 2020, respectively, which are also included in Income from Discontinued Operations, Net of Taxes and Amounts Attributable to Noncontrolling Interests . These costs primarily relate to professional fees for separation activities within finance, tax, legal and information technology functions, as well as investment banking fees. As of December 31, 2020, the assets and liabilities associated with these businesses are classified as assets and liabilities of discontinued operations in the condensed consolidated balance sheet. Details of Income from Discontinued Operations, Net of Taxes and Amounts Attributable to Noncontrolling Interests are as follows: Three Months Ended Nine Months Ended ($ in millions) 2020 2021 (1) 2020 Sales $ 1,622 $ 2,512 $ 4,911 Costs, Expenses and Other Cost of sales 468 789 1,362 Selling, general and administrative 390 877 1,046 Research and development 41 103 113 Restructuring costs 1 1 4 Other (income) expense, net — (15) 7 900 1,755 2,532 Income from discontinued operations before taxes 722 757 2,379 Tax provision (benefit) 103 (12) 343 Income from discontinued operations, net of taxes 619 769 2,036 Less: Income of discontinued operations attributable to noncontrolling interests 2 3 11 Income from discontinued operations, net of taxes and amounts attributable to noncontrolling interests $ 617 $ 766 $ 2,025 (1) Reflects amounts through the June 2, 2021 spin-off date. Details of assets and liabilities of discontinued operations are as follows: ($ in millions) December 31, 2020 Cash and cash equivalents $ 12 Accounts receivable, less allowance for doubtful accounts 1,048 Inventories 756 Other current assets 867 Current assets of discontinued operations $ 2,683 Property, plant and equipment, net $ 986 Goodwill 1,356 Other intangibles, net 503 Other assets 330 Noncurrent Assets of Discontinued Operations $ 3,175 Trade accounts payable $ 267 Accrued and other current liabilities 841 Income taxes payable (22) Total current liabilities of discontinued operations $ 1,086 Deferred income taxes $ 10 Other noncurrent liabilities 176 Noncurrent Liabilities of Discontinued Operations $ 186 As a result of the spin-off of Organon, Merck distributed net liabilities of $5.1 billion as of June 2, 2021 consisting of debt of $9.4 billion (described above), goodwill of $1.4 billion, property, plant and equipment of $981 million, cash of $929 million, inventory of $815 million, other intangibles, net, of $519 million and other net liabilities of $328 million. The spin-off also resulted in a net decrease to Accumulated other comprehensive loss ( AOCL ) of $449 million consisting of $421 million for the derecognition of net losses on foreign currency translation adjustments and $28 million associated with employee benefit plans. The distribution of the net liabilities and reduction to AOCL resulted in a net $4.6 billion increase to Other paid-in capital .

Acquisitions, Research Collabor

Acquisitions, Research Collaborations and License Agreements	9 Months Ended
	Sep. 30, 2021
Business Combination and Asset Acquisition [Abstract]
Acquisitions, Research Collaborations and License Agreements	Acquisitions, Research Collaborations and License Agreements The Company continues to pursue acquisitions and the establishment of external alliances such as research collaborations and licensing agreements to complement its internal research capabilities. These arrangements often include upfront payments, as well as expense reimbursements or payments to the third party, and milestone, royalty or profit share arrangements, contingent upon the occurrence of certain future events linked to the success of the asset in development. The Company also reviews its marketed products and pipeline to examine candidates which may provide more value through out-licensing and, as part of its portfolio assessment process, may also divest certain assets. Pro forma financial information for acquired businesses is not presented if the historical financial results of the acquired entity are not significant when compared with the Company’s financial results. In September 2021, Merck and Acceleron Pharma Inc. (Acceleron), a publicly traded biopharmaceutical company, entered into a definitive agreement under which Merck will acquire Acceleron for $180 per share in cash for an approximate total equity value of $11.5 billion. Acceleron is focused on harnessing the power of the transforming growth factor (TGF)-beta superfamily of proteins that is known to play a central role in the regulation of cell growth, differentiation and repair. Acceleron’s lead therapeutic candidate, sotatercept, has a novel mechanism of action with the potential to improve short-term and/or long-term clinical outcomes in patients with pulmonary arterial hypertension (PAH). Sotatercept is in Phase 3 trials as add-on to current standard of care for the treatment of PAH. In addition to sotatercept, Acceleron’s portfolio includes Reblozyl (luspatercept-aamt), a first-in-class erythroid maturation recombinant fusion protein approved in the U.S., Europe, Canada and Australia for the treatment of anemia in certain rare blood disorders. Reblozyl is being developed and commercialized through a global collaboration with Bristol Myers Squibb. Under the terms of the acquisition agreement, Merck, through a subsidiary, initiated a tender offer to acquire all outstanding shares of Acceleron. The closing of the tender offer is subject to certain conditions, including the tender of shares representing at least a majority of the total number of Acceleron’s outstanding shares, receipt of applicable regulatory approvals, and other customary conditions. The acquisition agreement includes termination provisions providing that (i) in the event Acceleron terminates in order to enter into an agreement with respect to a superior proposal (as defined in the agreement), Acceleron will be required to pay a termination fee of $345 million, and (ii) in the event the acquisition is not consummated due to antitrust conditions, Merck will be required to pay Acceleron a reverse termination fee of $650 million to $750 million depending on the time of termination. The transaction is expected to close in the fourth quarter of 2021. In April 2021, Merck acquired Pandion Therapeutics, Inc. (Pandion), a clinical-stage biotechnology company developing novel therapeutics designed to address the unmet needs of patients living with autoimmune diseases. Pandion is advancing a pipeline of precision immune modulators targeting critical immune control nodes. Total consideration paid of $1.9 billion included $147 million of transaction costs primarily comprised of share-based compensation payments to settle equity awards. The transaction was accounted for as an acquisition of an asset. Merck recorded net assets of $156 million (primarily cash) and Research and development expenses of $1.7 billion in the first nine months of 2021 related to the transaction. There are no future contingent payments associated with the acquisition. In March 2021, Merck and Gilead Sciences, Inc. (Gilead) entered into an agreement to jointly develop and commercialize long-acting treatments in HIV that combine Merck’s investigational nucleoside reverse transcriptase translocation inhibitor, islatravir, and Gilead’s investigational capsid inhibitor, lenacapavir. The collaboration will initially focus on long-acting oral formulations and long-acting injectable formulations of these combination products, with other formulations potentially added to the collaboration as mutually agreed. There was no upfront payment made by either party upon entering into the agreement. Under the terms of the agreement, Gilead and Merck will share operational responsibilities, as well as development, commercialization and marketing costs, and any future revenues. Global development and commercialization costs will be shared 60% Gilead and 40% Merck across the oral and injectable formulation programs. For long-acting oral products, Gilead will lead commercialization in the U.S. and Merck will lead commercialization in the EU and the rest of the world. For long-acting injectable products, Merck will lead commercialization in the U.S. and Gilead will lead commercialization in the EU and the rest of the world. Gilead and Merck will co-promote in the U.S. and certain other major markets. Merck and Gilead will share global product revenues equally until product revenues surpass certain pre-agreed per formulation revenue tiers. Upon passing $2.0 billion a year in net product sales for the oral combination, the revenue split will adjust to 65% Gilead and 35% Merck for any revenues above the threshold. Upon passing $3.5 billion a year in net product sales for the injectable combination, the revenue split will adjust to 65% Gilead and 35% Merck for any revenues above the threshold. Beyond the potential combinations of investigational lenacapavir and investigational islatravir, Gilead will have the option to license certain of Merck’s investigational oral integrase inhibitors to develop in combination with lenacapavir. Reciprocally, Merck will have the option to license certain of Gilead’s investigational oral integrase inhibitors to develop in combination with islatravir. Each company may exercise its option for an investigational oral integrase inhibitor of the other company following completion of the first Phase 1 clinical trial of that integrase inhibitor. Upon exercise of an option, the companies will split development costs and revenues, unless the non-exercising company decides to opt-out. In January 2021, Merck entered into an exclusive license and research collaboration agreement with Artiva Biotherapeutics, Inc. (Artiva) to discover, develop and manufacture CAR-NK cells that target certain solid tumors using Artiva’s proprietary platform. Merck and Artiva agreed to engage in up to three different research programs, each covering a collaboration target. Merck has sole responsibility for all development and commercialization activities (including regulatory filing and approval). Under the terms of the agreement, Merck made an upfront payment of $30 million, which was included in Research and development expenses in the first nine months of 2021, for license and other rights for the first two collaboration targets and agreed to make another upfront payment of $15 million for license and other rights for the third collaboration target when it is selected by Merck and accepted by Artiva. In addition, Artiva is eligible to receive future contingent milestone payments (which span all three collaboration targets), aggregating up to: $217.5 million in developmental milestones, $570 million in regulatory milestones, and $1.05 billion in sales-based milestones. The agreement also provides for Merck to pay tiered royalties ranging from 7% to 14% on future sales. In December 2020, Merck acquired OncoImmune, a privately held, clinical-stage biopharmaceutical company, for an upfront payment of $423 million. OncoImmune’s lead therapeutic candidate MK-7110 (formerly known as CD24Fc) was being evaluated for the treatment of patients hospitalized with coronavirus disease 2019 (COVID-19). The transaction was accounted for as an acquisition of an asset. Under the agreement, prior to the completion of the acquisition, OncoImmune spun-out certain rights and assets unrelated to the MK-7110 program to a new entity owned by the existing shareholders of OncoImmune. In connection with the closing of the acquisition, Merck invested $50 million for a 20% ownership interest in the new entity, which was valued at $33 million resulting in a $17 million premium. Merck also recognized other net liabilities of $22 million. The Company recorded Research and development expenses of $462 million in 2020 related to this transaction. In 2021, Merck received feedback from the U.S. Food and Drug Administration (FDA) that additional data would be needed to support a potential Emergency Use Authorization application and therefore the Company did not expect MK-7110 would become available until the first half of 2022. Given this timeline and the technical, clinical and regulatory uncertainties, the availability of a number of medicines for patients hospitalized with COVID-19, and the need to concentrate Merck’s resources on accelerating the development and manufacture of the most viable therapeutics and vaccines, Merck decided to discontinue development of MK-7110 for the treatment of COVID-19. Due to the discontinuation, the Company recorded charges of $207 million in the first nine months of 2021, which are reflected in Cost of sales and relate to fixed-asset and materials write-offs, as well as the recognition of liabilities for purchase commitments . In September 2020, Merck and Seagen Inc. (Seagen, formerly known as Seattle Genetics, Inc.) announced an oncology collaboration to globally develop and commercialize Seagen’s ladiratuzumab vedotin (MK-6440), an investigational antibody-drug conjugate targeting LIV-1, which is currently in Phase 2 clinical trials. The collaboration will pursue a broad joint development program evaluating ladiratuzumab vedotin as monotherapy and in combination with Keytruda (pembrolizumab) in triple-negative breast cancer, hormone receptor-positive breast cancer and other LIV-1-expressing solid tumors. The companies will equally share profits worldwide. Under the terms of the agreement, Merck made an upfront payment of $600 million and a $1.0 billion equity investment in 5 million shares of Seagen common stock at a price of $200 per share. Merck recorded $622 million in Research and development expenses in the third quarter and first nine months of 2020 related to this transaction reflecting the upfront payment as well as a $22 million mark-to-market loss on the purchase commitment (forward contract) relating to the equity shares (calculated based on the closing price of Seagen common stock on September 30, 2020). The closing of the equity investment occurred in October 2020 and resulted in the recognition of a $6 million reduction to Research and development expenses based on the price of Seagen common stock on the closing date. Seagen is also eligible to receive future contingent milestone payments of up to $2.6 billion, including $850 million in development milestones and $1.75 billion in sales-based milestones. Concurrent with the above transaction, Seagen granted Merck an exclusive license to commercialize Tukysa (tucatinib), a small molecule tyrosine kinase inhibitor, for the treatment of human epidermal growth factor receptor 2 (HER2)- positive cancers, in Asia, the Middle East and Latin America and other regions outside of the U.S., Canada and Europe. Merck will be responsible for marketing applications seeking approval in its territories, supported by the positive results from the HER2CLIMB clinical trial. Merck will also co-fund a portion of the Tukysa global development plan, which encompasses several ongoing and planned trials across HER2-positive cancers, including breast, colorectal, gastric and other cancers set forth in a global product development plan. Merck will solely fund and conduct country-specific clinical trials necessary to support anticipated regulatory applications in its territories. Under the terms of the agreement, Merck made upfront payments aggregating $210 million, which were recorded as Research and development expenses in the third quarter and first nine months of 2020. Seagen is also eligible to receive future contingent regulatory approval milestones of up to $65 million and will receive tiered royalties ranging from 20% to 33% based on annual sales levels of Tukysa in Merck’s territories. Additionally in September 2020, Merck acquired a biologics manufacturing facility located in Dunboyne, Ireland from Takeda Pharmaceutical Company Limited for €256 million ($302 million). The transaction was accounted for as an acquisition of an asset. Merck recorded property, plant and equipment of $289 million and other net assets of $13 million. There are no future contingent payments associated with the acquisition. In July 2020, Merck acquired the U.S. rights to Sentinel Flavor Tabs and Sentinel Spectrum Chews from Virbac Corporation for $410 million. Sentinel products provide protection against common parasites in dogs. The transaction was accounted for as an acquisition of an asset. Merck recognized intangible assets of $401 million related to currently marketed products and inventory of $9 million at the acquisition date. The estimated fair values of the identifiable intangible assets related to currently marketed products were determined using an income approach. Actual cash flows are likely to be different than those assumed. The intangible assets related to currently marketed products will be amortized over their estimated useful lives of 15 years. There are no future contingent payments associated with the acquisition. Also in July 2020, Merck and Ridgeback Biotherapeutics LP (Ridgeback Bio), a closely held biotechnology company, closed a collaboration agreement to develop molnupiravir (MK-4482/EIDD-2801) an orally available antiviral candidate in clinical development for the treatment of patients with COVID-19. Merck gained exclusive worldwide rights to develop and commercialize molnupiravir and related molecules. Under the terms of the agreement, Ridgeback Bio received an upfront payment and is eligible to receive future contingent payments dependent upon the achievement of certain developmental and regulatory approval milestones. Any profits from the collaboration will be split between the partners equally. Merck and Ridgeback Bio are committed to ensure that any medicines developed for SARS-CoV-2 (the causative agent of COVID-19) will be accessible and affordable globally. In June 2020, Merck acquired privately held Themis Bioscience GmbH (Themis), a company focused on vaccines (including a COVID-19 vaccine candidate, V591) and immune-modulation therapies for infectious diseases and cancer for $366 million. The acquisition originally provided for Merck to make additional contingent payments of up to $740 million. The transaction was accounted for as an acquisition of a business. The Company determined the fair value of the contingent consideration was $85 million at the acquisition date utilizing a probability-weighted estimated cash flow stream using an appropriate discount rate dependent on the nature and timing of the milestone payments. Merck recognized intangible assets for in-process research and development (IPR&D) of $113 million, cash of $59 million, deferred tax assets of $72 million and other net liabilities of $32 million. The excess of the consideration transferred over the fair value of net assets acquired of $239 million was recorded as goodwill that was allocated to the Pharmaceutical segment and is not deductible for tax purposes. The fair values of the identifiable intangible assets related to IPR&D were determined using an income approach. Actual cash flows are likely to be different than those assumed. In January 2021, the Company announced it was discontinuing development of V591. As a result, in the fourth quarter of 2020, the Company recorded an IPR&D impairment charge of $90 million within Research and development expenses. The Company also recorded a reduction in Research and development expenses resulting from a decrease in the related liability for contingent consideration of $45 million since future contingent milestone payments have been reduced to $450 million in the aggregate, including up to $60 million for development milestones, up to $196 million for regulatory approval milestones, and up to $194 million for commercial milestones. In January 2020, Merck acquired ArQule, Inc. (ArQule), a publicly traded biopharmaceutical company focused on kinase inhibitor discovery and development for the treatment of patients with cancer and other diseases. Total consideration paid of $2.7 billion included $138 million of share-based compensation payments to settle equity awards attributable to precombination service and cash paid for transaction costs on behalf of ArQule. The Company incurred $95 million of transaction costs directly related to the acquisition of ArQule, consisting almost entirely of share-based compensation payments to settle non-vested equity awards attributable to postcombination service. These costs were included in Selling, general and administrative expenses in the first nine months of 2020. ArQule’s lead investigational candidate, MK-1026 (formerly known as ARQ 531), is a novel, oral Bruton’s tyrosine kinase (BTK) inhibitor currently being evaluated for the treatment of B-cell malignancies. The transaction was accounted for as an acquisition of a business. The estimated fair value of assets acquired and liabilities assumed from ArQule is as follows: ($ in millions) January 16, 2020 Cash and cash equivalents $ 145 IPR&D MK-1026 (formerly ARQ 531) (1) 2,280 Licensing arrangement for ARQ 087 80 Deferred income tax liabilities (361) Other assets and liabilities, net 34 Total identifiable net assets 2,178 Goodwill (2) 512 Consideration transferred $ 2,690 (1) The estimated fair value of the identifiable intangible asset related to IPR&D was determined using an income approach. The future net cash flows were discounted to present value utilizing a discount rate of 12.5%. Actual cash flows are likely to be different than those assumed. (2) The goodwill was allocated to the Pharmaceutical segment and is not deductible for tax purposes.

Collaborative Arrangements

Collaborative Arrangements	9 Months Ended
	Sep. 30, 2021
Collaborative Arrangements [Abstract]
Collaborative Arrangements	Collaborative Arrangements Merck has entered into collaborative arrangements that provide the Company with varying rights to develop, produce and market products together with its collaborative partners. Both parties in these arrangements are active participants and exposed to significant risks and rewards dependent on the commercial success of the activities of the collaboration. Merck’s more significant collaborative arrangements are discussed below. For further details refer to Note 4 to the consolidated financial statements included in Merck’s 2020 Form 10‑K. AstraZeneca In 2017, Merck and AstraZeneca PLC (AstraZeneca) entered into a global strategic oncology collaboration to co-develop and co-commercialize AstraZeneca’s Lynparza (olaparib) for multiple cancer types. Independently, Merck and AstraZeneca will develop and commercialize Lynparza in combinations with their respective PD-1 and PD-L1 medicines, Keytruda and Imfinzi. The companies are also jointly developing and commercializing AstraZeneca’s Koselugo (selumetinib) for multiple indications. Under the terms of the agreement, AstraZeneca and Merck will share the development and commercialization costs for Lynparza and Koselugo monotherapy and non-PD-L1/PD-1 combination therapy opportunities. Profits from Lynparza and Koselugo product sales generated through monotherapies or combination therapies are shared equally. AstraZeneca is the principal on Lynparza and Koselugo sales transactions. Merck records its share of Lynparza and Koselugo product sales, net of cost of sales and commercialization costs, as alliance revenue and its share of development costs associated with the collaboration as part of Research and development expenses. Reimbursements received from AstraZeneca for research and development expenses are recognized as reductions to Research and development costs. As part of the agreement, Merck made an upfront payment to AstraZeneca and also made payments over a multi-year period for certain license options. In addition, the agreement provides for additional contingent payments from Merck to AstraZeneca related to the successful achievement of sales-based and regulatory milestones. As of September 30, 2021, sales-based milestone payments accrued but not yet paid totaled $400 million. Potential future sales-based milestone payments of $2.7 billion have not yet been accrued as they are not deemed by the Company to be probable at this time. Additionally, potential future regulatory milestone payments of $1.4 billion remain under the agreement. The intangible asset balance related to Lynparza (which includes capitalized sales-based and regulatory milestone payments) was $1.1 billion at September 30, 2021 and is included in Other Intangibles, Net . The amount is being amortized over its estimated useful life through 2028 as supported by projected future cash flows, subject to impairment testing. Summarized financial information related to this collaboration is as follows: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Alliance revenue - Lynparza $ 246 $ 196 $ 721 $ 519 Alliance revenue - Koselugo 6 3 20 3 Total alliance revenue $ 252 $ 199 $ 741 $ 522 Cost of sales (1) 42 41 125 205 Selling, general and administrative 44 40 127 112 Research and development 27 20 87 93 ($ in millions) September 30, 2021 December 31, 2020 Receivables from AstraZeneca included in Other current assets $ 248 $ 215 Payables to AstraZeneca included in Accrued and other current liabilities (2) 415 423 (1) Represents amortization of capitalized milestone payments. (2) Includes accrued milestone payments. Eisai In 2018, Merck and Eisai Co., Ltd. (Eisai) announced a strategic collaboration for the worldwide co-development and co-commercialization of Lenvima (lenvatinib), an orally available tyrosine kinase inhibitor discovered by Eisai. Under the agreement, Merck and Eisai will develop and commercialize Lenvima jointly, both as monotherapy and in combination with Keytruda . Eisai records Lenvima product sales globally (Eisai is the principal on Lenvima sales transactions), and Merck and Eisai share applicable profits equally. Merck records its share of Lenvima product sales, net of cost of sales and commercialization costs, as alliance revenue. Expenses incurred during co-development are shared by the two companies in accordance with the collaboration agreement and reflected in Research and development expenses. Certain expenses incurred solely by Merck or Eisai are not shareable under the collaboration agreement, including costs incurred in excess of agreed upon caps and costs related to certain combination studies of Keytruda and Lenvima. Under the agreement, Merck made an upfront payment to Eisai and also made payments over a multi-year period for certain options rights (of which the final $125 million option payment was made in March 2021). In addition, the agreement provides for additional contingent payments from Merck to Eisai related to the successful achievement of sales-based and regulatory milestones. Merck made sales-based milestone payments of $200 million to Eisai in the first nine months of 2021. As of September 30, 2021, sales-based milestone payments accrued but not yet paid totaled $600 million. Potential future sales-based milestone payments of $2.6 billion have not yet been accrued as they are not deemed by the Company to be probable at this time. In the third quarter of 2021, Lenvima received a regulatory approval triggering a capitalized milestone payment of $75 million from Merck to Eisai. Potential future regulatory milestone payments of $50 million remain under the agreement. The intangible asset balance related to Lenvima (which includes capitalized sales-based and regulatory milestone payments) was $1.0 billion at September 30, 2021 and is included in Other Intangibles, Net . The amount is being amortized over its estimated useful life through 2026 as supported by projected future cash flows, subject to impairment testing. Summarized financial information related to this collaboration is as follows: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Alliance revenue - Lenvima $ 188 $ 142 $ 498 $ 421 Cost of sales (1) 49 46 143 215 Selling, general and administrative 34 18 88 48 Research and development 43 48 165 168 ($ in millions) September 30, 2021 December 31, 2020 Receivables from Eisai included in Other current assets $ 223 $ 157 Payables to Eisai included in Accrued and other current liabilities (2) 600 335 Payables to Eisai included in Other Noncurrent Liabilities (3) — 600 (1) Represents amortization of capitalized milestone payments. (2) Includes accrued milestone and future option payments. (3) Includes accrued milestone payments. Bayer AG In 2014, the Company entered into a worldwide clinical development collaboration with Bayer AG (Bayer) to market and develop soluble guanylate cyclase (sGC) modulators including Bayer’s Adempas (riociguat). The two companies have implemented a joint development and commercialization strategy. The collaboration also includes development of Bayer’s Verquvo (vericiguat), which was approved in the U.S. in January 2021, in Japan in June 2021 and in the EU in July 2021. Under the agreement, Bayer commercializes Adempas in the Americas, while Merck commercializes in the rest of the world. For Verquvo, Merck commercializes in the U.S. and Bayer commercializes in the rest of the world. Both companies share in development costs and profits on sales. Merck records sales of Adempas and Verquvo in its marketing territories, as well as alliance revenue. Alliance revenue represents Merck’s share of profits from sales in Bayer’s marketing territories, which are product sales net of cost of sales and commercialization costs. Cost of sales includes Bayer’s share of profits from sales in Merck’s marketing territories. In addition, the agreement provides for contingent payments from Merck to Bayer related to the successful achievement of sales-based milestones. In the first quarter of 2021, following the approval of Verquvo noted above, Merck determined it was probable that sales of Adempas and Verquvo in the future would trigger the remaining $400 million sales-based milestone payment that was outstanding under this agreement. Accordingly, Merck recorded a liability of $400 million and a corresponding increase to the intangible assets related to this collaboration. Merck also recognized $153 million of cumulative amortization expense related to the recognition of this milestone in the first nine months of 2021. The intangible asset balance related to Adempas (which includes the acquired intangible asset balance, as well as capitalized sales-based milestone payments attributed to Adempas) was $869 million at September 30, 2021 and is being amortized over its estimated useful life through 2027 as supported by projected future cash flows, subject to impairment testing. The intangible asset balance related to Verquvo (which reflects the portion of the final sales-based milestone payment that was attributed to Verquvo) was $72 million at September 30, 2021 and is being amortized over its estimated useful life through 2031 as supported by projected future cash flows, subject to impairment testing. Summarized financial information related to this collaboration is as follows: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Alliance revenue - Adempas/Verquvo $ 100 $ 83 $ 248 $ 216 Net sales of Adempas recorded by Merck 59 55 188 167 Net sales of Verquvo recorded by Merck 2 — 3 — Total sales $ 161 $ 138 $ 439 $ 383 Cost of sales (1) 53 81 328 229 Selling, general and administrative 31 12 84 32 Research and development 16 12 36 53 ($ in millions) September 30, 2021 December 31, 2020 Receivables from Bayer included in Other current assets $ 139 $ 65 Payables to Bayer included in Accrued and other current liabilities (2) 467 — (1) Includes amortization of intangible assets. Amount in the first nine months of 2021 includes $153 million of cumulative amortization as noted above. In addition, cost of sales in all periods now includes Bayer’s share of profits from sales in Merck’s marketing territories. (2) Includes accrued milestone payment.

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2021
Restructuring and Related Activities [Abstract]
Restructuring	Restructuring In 2019, Merck approved a new global restructuring program (Restructuring Program) as part of a worldwide initiative focused on further optimizing the Company’s manufacturing and supply network, as well as reducing its global real estate footprint. This program is a continuation of the Company’s plant rationalization, builds on prior restructuring programs and does not include any actions associated with the spin-off of Organon. As the Company continues to evaluate its global footprint and overall operating model, it subsequently identified additional actions under the Restructuring Program, and could identify further actions over time. The actions currently contemplated under the Restructuring Program are expected to be substantially completed by the end of 2023, with the cumulative pretax costs to be incurred by the Company to implement the program estimated to be approximately $3.0 billion. The Company estimates that approximately 70% of the cumulative pretax costs will result in cash outlays, primarily related to employee separation expense and facility shut-down costs. Approximately 30% of the cumulative pretax costs will be non-cash, relating primarily to the accelerated depreciation of facilities to be closed or divested. The Company recorded total pretax costs of $168 million and $185 million in the third quarter of 2021 and 2020, respectively, and $630 million and $500 million for the first nine months of 2021 and 2020, respectively, related to restructuring program activities. Since inception of the Restructuring Program through September 30, 2021, Merck has recorded total pretax accumulated costs of approximately $2.4 billion. For the full year of 2021, the Company expects to record charges of approximately $700 million related to the Restructuring Program. For segment reporting, restructuring charges are unallocated expenses. The following tables summarize the charges related to restructuring program activities by type of cost: Three Months Ended September 30, 2021 Nine Months Ended September 30, 2021 ($ in millions) Separation Accelerated Other Total Separation Accelerated Other Total Cost of sales $ — $ 11 $ 37 $ 48 $ — $ 32 $ 81 $ 113 Selling, general and administrative — 4 1 5 — 8 1 9 Research and development — 7 1 8 — 20 1 21 Restructuring costs 17 — 90 107 310 — 177 487 $ 17 $ 22 $ 129 $ 168 $ 310 $ 60 $ 260 $ 630 Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 ($ in millions) Separation Accelerated Other Total Separation Accelerated Other Total Cost of sales $ — $ 33 $ 5 $ 38 $ — $ 89 $ 42 $ 131 Selling, general and administrative — 15 — 15 — 37 — 37 Research and development — 18 1 19 — 66 1 67 Restructuring costs 61 — 52 113 143 — 122 265 $ 61 $ 66 $ 58 $ 185 $ 143 $ 192 $ 165 $ 500 Separation costs are associated with actual headcount reductions, as well as those headcount reductions which were probable and could be reasonably estimated. Accelerated depreciation costs primarily relate to manufacturing, research and administrative facilities and equipment to be sold or closed as part of the programs. Accelerated depreciation costs represent the difference between the depreciation expense to be recognized over the revised useful life of the asset, based upon the anticipated date the site will be closed or divested or the equipment disposed of, and depreciation expense as determined utilizing the useful life prior to the restructuring actions. All the sites have and will continue to operate up through the respective closure dates and, since future undiscounted cash flows are sufficient to recover the respective book values, Merck is recording accelerated depreciation over the revised useful life of the site assets. Anticipated site closure dates, particularly related to manufacturing locations, have been and may continue to be adjusted to reflect changes resulting from regulatory or other factors. Other activity in 2021 and 2020 includes asset abandonment, facility shut-down and other related costs, as well as pretax gains and losses resulting from the sales of facilities and related assets. Additionally, other activity includes certain employee-related costs associated with pension and other postretirement benefit plans (see Note 11) and share-based compensation. The following table summarizes the charges and spending relating to restructuring program activities for the nine months ended September 30, 2021: ($ in millions) Separation Accelerated Other Total Restructuring reserves January 1, 2021 $ 567 $ — $ 19 $ 586 Expense 310 60 260 630 (Payments) receipts, net (305) — (155) (460) Non-cash activity — (60) (84) (144) Restructuring reserves September 30, 2021 (1) $ 572 $ — $ 40 $ 612

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	Financial Instruments Derivative Instruments and Hedging Activities The Company manages the impact of foreign exchange rate movements and interest rate movements on its earnings, cash flows and fair values of assets and liabilities through operational means and through the use of various financial instruments, including derivative instruments. A significant portion of the Company’s revenues and earnings in foreign affiliates is exposed to changes in foreign exchange rates. The objectives and accounting related to the Company’s foreign currency risk management program, as well as its interest rate risk management activities are discussed below. Foreign Currency Risk Management The Company has established revenue hedging, balance sheet risk management and net investment hedging programs to protect against volatility of future foreign currency cash flows and changes in fair value caused by changes in foreign exchange rates. The objective of the revenue hedging program is to reduce the variability caused by changes in foreign exchange rates that would affect the U.S. dollar value of future cash flows derived from foreign currency denominated sales, primarily the euro, Japanese yen and Chinese renminbi. To achieve this objective, the Company will hedge a portion of its forecasted foreign currency denominated third-party and intercompany distributor entity sales (forecasted sales) that are expected to occur over its planning cycle, typically no more than two years into the future. The Company will layer in hedges over time, increasing the portion of forecasted sales hedged as it gets closer to the expected date of the forecasted sales. The portion of forecasted sales hedged is based on assessments of cost-benefit profiles that consider natural offsetting exposures, revenue and exchange rate volatilities and correlations, and the cost of hedging instruments. The Company manages its anticipated transaction exposure principally with purchased local currency put options, forward contracts and purchased collar options. The fair values of these derivative contracts are recorded as either assets (gain positions) or liabilities (loss positions) in the Condensed Consolidated Balance Sheet. Changes in the fair value of derivative contracts are recorded each period in either current earnings or Other comprehensive income ( OCI ), depending on whether the derivative is designated as part of a hedge transaction and, if so, the type of hedge transaction. For derivatives that are designated as cash flow hedges, the unrealized gains or losses on these contracts are recorded in AOCL and reclassified into Sales when the hedged anticipated revenue is recognized. For those derivatives which are not designated as cash flow hedges, but serve as economic hedges of forecasted sales, unrealized gains or losses are recorded in Sales each period. The cash flows from both designated and non- designated contracts are reported as operating activities in the Condensed Consolidated Statement of Cash Flows. The Company does not enter into derivatives for trading or speculative purposes. The Company manages operating activities and net asset positions at each local subsidiary in order to mitigate the effects of exchange on monetary assets and liabilities. The Company also uses a balance sheet risk management program to mitigate the exposure of net monetary assets that are denominated in a currency other than a subsidiary’s functional currency from the effects of volatility in foreign exchange. In these instances, Merck principally utilizes forward exchange contracts to offset the effects of exchange on exposures denominated in developed country currencies, primarily the euro and Japanese yen. For exposures in developing country currencies, the Company will enter into forward contracts to partially offset the effects of exchange on exposures when it is deemed economical to do so based on a cost-benefit analysis that considers the magnitude of the exposure, the volatility of the exchange rate and the cost of the hedging instrument. The cash flows from these contracts are reported as operating activities in the Condensed Consolidated Statement of Cash Flows. Monetary assets and liabilities denominated in a currency other than the functional currency of a given subsidiary are remeasured at spot rates in effect on the balance sheet date with the effects of changes in spot rates reported in Other (income) expense, net . The forward contracts are not designated as hedges and are marked to market through Other (income) expense, net . Accordingly, fair value changes in the forward contracts help mitigate the changes in the value of the remeasured assets and liabilities attributable to changes in foreign currency exchange rates, except to the extent of the spot-forward differences. These differences are not significant due to the short-term nature of the contracts, which typically have average maturities at inception of less than one year. The Company also uses forward exchange contracts to hedge a portion of its net investment in foreign operations against movements in exchange rates. The forward contracts are designated as hedges of the net investment in a foreign operation. The unrealized gains or losses on these contracts are recorded in foreign currency translation adjustment within OCI and remain in AOCL until either the sale or complete or substantially complete liquidation of the subsidiary. The Company excludes certain portions of the change in fair value of its derivative instruments from the assessment of hedge effectiveness (excluded components). Changes in fair value of the excluded components are recognized in OCI . The Company recognizes in earnings the initial value of the excluded components on a straight-line basis over the life of the derivative instrument, rather than using the mark-to-market approach. The cash flows from these contracts are reported as investing activities in the Condensed Consolidated Statement of Cash Flows. Foreign exchange risk is also managed through the use of foreign currency debt. The Company’s senior unsecured euro-denominated notes have been designated as, and are effective as, economic hedges of the net investment in a foreign operation. Accordingly, foreign currency transaction gains or losses due to spot rate fluctuations on the euro-denominated debt instruments are included in foreign currency translation adjustment within OCI . The effects of the Company’s net investment hedges on OCI and the Consolidated Statement of Income are shown below: Amount of Pretax (Gain) Loss Recognized in Other Comprehensive Income (1) Amount of Pretax (Gain) Loss Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing Three Months Ended September 30, Nine Months Ended September 30, Three Months Ended September 30, Nine Months Ended September 30, ($ in millions) 2021 2020 2021 2020 2021 2020 2021 2020 Net Investment Hedging Relationships Foreign exchange contracts $ 1 $ 10 $ (27) $ 15 $ (4) $ (4) $ (12) $ (15) Euro-denominated notes (77) 162 (199) 182 — — — — (1) No amounts were reclassified from AOCL into income related to the sale of a subsidiary. Interest Rate Risk Management The Company may use interest rate swap contracts on certain investing and borrowing transactions to manage its net exposure to interest rate changes and to reduce its overall cost of borrowing. The Company does not use leveraged swaps and, in general, does not leverage any of its investment activities that would put principal capital at risk. In January 2021, five interest rate swaps with a total notional amount of $1.15 billion matured. These swaps effectively converted the Company’s $1.15 billion, 3.875% fixed-rate notes due 2021 to variable rate debt. At September 30, 2021, the Company was a party to nine pay-floating, receive-fixed interest rate swap contracts designated as fair value hedges of fixed-rate notes in which the notional amounts match the amount of the hedged fixed-rate notes as detailed in the table below. September 30, 2021 ($ in millions) Par Value of Debt Number of Interest Rate Swaps Held Total Swap Notional Amount 2.40% notes due 2022 $ 1,000 4 $ 1,000 2.35% notes due 2022 1,250 5 1,250 The interest rate swap contracts are designated hedges of the fair value changes in the notes attributable to changes in the benchmark LIBOR swap rate. The fair value changes in the notes attributable to changes in the LIBOR swap rate are recorded in interest expense along with the offsetting fair value changes in the swap contracts. The cash flows from these contracts are reported as operating activities in the Condensed Consolidated Statement of Cash Flows. The table below presents the location of amounts recorded on the Condensed Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges: Carrying Amount of Hedged Liabilities Cumulative Amount of Fair Value Hedging Adjustment Increase (Decrease) Included in the Carrying Amount ($ in millions) September 30, 2021 December 31, 2020 September 30, 2021 December 31, 2020 Loans payable and current portion of long-term debt $ 2,274 $ 1,150 $ 25 $ — Long-Term Debt — 2,301 — 53 Presented in the table below is the fair value of derivatives on a gross basis segregated between those derivatives that are designated as hedging instruments and those that are not designated as hedging instruments: September 30, 2021 December 31, 2020 Fair Value of Derivative U.S. Dollar Fair Value of Derivative U.S. Dollar ($ in millions) Asset Liability Asset Liability Derivatives Designated as Hedging Instruments Balance Sheet Caption Interest rate swap contracts Other current assets $ 26 $ — $ 2,250 $ 1 $ — $ 1,150 Interest rate swap contracts Other Assets — — — 54 — 2,250 Foreign exchange contracts Other current assets 224 — 7,138 12 — 3,183 Foreign exchange contracts Other Assets 45 — 1,469 45 — 2,030 Foreign exchange contracts Accrued and other current liabilities — 15 1,601 — 217 5,049 Foreign exchange contracts Other Noncurrent Liabilities — 1 145 — 1 52 $ 295 $ 16 $ 12,603 $ 112 $ 218 $ 13,714 Derivatives Not Designated as Hedging Instruments Balance Sheet Caption Foreign exchange contracts Other current assets $ 82 $ — $ 6,333 $ 70 $ — $ 7,260 Foreign exchange contracts Accrued and other current liabilities — 117 9,522 — 307 11,810 $ 82 $ 117 $ 15,855 $ 70 $ 307 $ 19,070 $ 377 $ 133 $ 28,458 $ 182 $ 525 $ 32,784 As noted above, the Company records its derivatives on a gross basis in the Condensed Consolidated Balance Sheet. The Company has master netting agreements with several of its financial institution counterparties (see Concentrations of Credit Risk below). The following table provides information on the Company’s derivative positions subject to these master netting arrangements as if they were presented on a net basis, allowing for the right of offset by counterparty and cash collateral exchanged per the master agreements and related credit support annexes: September 30, 2021 December 31, 2020 ($ in millions) Asset Liability Asset Liability Gross amounts recognized in the condensed consolidated balance sheet $ 377 $ 133 $ 182 $ 525 Gross amounts subject to offset in master netting arrangements not offset in the condensed consolidated balance sheet (120) (120) (156) (156) Cash collateral received/posted (65) — — (36) Net amounts $ 192 $ 13 $ 26 $ 333 The table below provides information regarding the location and amount of pretax (gains) losses of derivatives designated in fair value or cash flow hedging relationships (including amounts attributable to discontinued operations): Sales Other (income) expense, net (1) Other comprehensive income (loss) Sales Other (income) expense, net (1) Other comprehensive income (loss) Three Months Ended September 30, Three Months Ended September 30, Three Months Ended September 30, Nine Months Ended September 30, Nine Months Ended September 30, Nine Months Ended September 30, ($ in millions) 2021 2020 2021 2020 2021 2020 2021 2020 2021 2020 2021 2020 Financial Statement Line Items in which Effects of Fair Value or Cash Flow Hedges are Recorded $ 13,154 $ 10,929 $ (450) $ (312) $ 38 $ 10 $ 35,183 $ 30,570 $ (1,007) $ (637) $ 1,595 $ (190) (Gain) loss on fair value hedging relationships Interest rate swap contracts Hedged items — — (9) (14) — — — — (29) 54 — — Derivatives designated as hedging instruments — — (1) — — — — — (1) (76) — — Impact of cash flow hedging relationships Foreign exchange contracts Amount of gain (loss) recognized in OCI on derivatives — — — — 72 (195) — — — — 193 (126) (Decrease) increase in Sales as a result of AOCL reclassifications (36) (23) — — 36 23 (219) 65 — — 219 (65) Interest rate contracts Amount of gain recognized in Other (income) expense, net on derivatives — — — (1) — — — — (2) (3) — — Amount of loss recognized in OCI on derivatives — — — — — (1) — — — — (2) (3) (1) Interest expense is a component of Other (income) expense, net. The table below provides information regarding the income statement effects of derivatives not designated as hedging instruments (including amounts attributable to discontinued operations): Amount of Derivative Pretax (Gain) Loss Recognized in Income Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Derivatives Not Designated as Hedging Instruments Income Statement Caption Foreign exchange contracts (1) Other (income) expense, net $ 18 $ (7) $ 234 $ (138) Foreign exchange contracts (2) Sales (4) 7 6 4 Interest rate contracts (3) Other (income) expense, net — — — 9 Forward contract related to Seagen common stock Research and development — 22 — 22 (1) These derivative contracts primarily mitigate changes in the value of remeasured foreign currency denominated monetary assets and liabilities attributable to changes in foreign currency exchange rates. Amount in the first nine months of 2021 includes a loss on forward exchange contracts entered into in conjunction with the spin-off of Organon. (2) These derivative contracts serve as economic hedges of forecasted transactions. (3) These derivative contracts serve as economic hedges against rising treasury rates. At September 30, 2021, the Company estimates $55 million of pretax net unrealized gains on derivatives maturing within the next 12 months that hedge foreign currency denominated sales over that same period will be reclassified from AOCL to Sales . The amount ultimately reclassified to Sales may differ as foreign exchange rates change. Realized gains and losses are ultimately determined by actual exchange rates at maturity. Investments in Debt and Equity Securities Information on investments in debt and equity securities is as follows: September 30, 2021 December 31, 2020 Amortized Gross Unrealized Fair Amortized Gross Unrealized Fair ($ in millions) Gains Losses Gains Losses U.S. government and agency securities $ 83 $ — $ — $ 83 $ 84 $ — $ — $ 84 Corporate notes and bonds 4 — — 4 — — — — Foreign government bonds 2 — — 2 5 — — 5 Total debt securities $ 89 $ — $ — $ 89 $ 89 $ — $ — $ 89 Publicly traded equity securities (1) 1,915 1,787 Total debt and publicly traded equity securities $ 2,004 $ 1,876 (1) Unrealized net gains of $90 million and unrealized net losses of $109 million were recorded in Other (income) expense, net on equity securities still held at September 30, 2021 in the third quarter and first nine months of 2021, respectively. Unrealized net gains recorded in Other (income) expense, net on equity securities still held at September 30, 2020 were $43 million and $512 million in the third quarter and first nine months of 2020, respectively. At September 30, 2021 and September 30, 2020, the Company also had $578 million and $508 million, respectively, of equity investments without readily determinable fair values included in Other Assets . The Company recognizes unrealized gains on these equity investments based on favorable observable price changes from transactions involving similar investments of the same investee and recognizes unrealized losses based on unfavorable observable price changes. During the first nine months of 2021 , the Company recorded unrealized gains of $104 million and unrealized losses of $1 million in Other (income) expense, net related to these equity investments held at September 30, 2021. During the first nine months of 2020 , the Company recorded unrealized gains of $21 million and unrealized losses of $3 million in Other (income) expense, net related to these equity investments held at September 30, 2020. Cumulative unrealized gains and cumulative unrealized losses based on observable prices changes for investments in equity investments without readily determinable fair values still held at September 30, 2021 were $229 million and $7 million, respectively. Fair Value Measurements Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company uses a fair value hierarchy which maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value. There are three levels of inputs used to measure fair value with Level 1 having the highest priority and Level 3 having the lowest: Level 1 - Quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 - Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; Level 3 - Unobservable inputs that are supported by little or no market activity. Level 3 assets or liabilities are those whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques with significant unobservable inputs, as well as assets or liabilities for which the determination of fair value requires significant judgment or estimation. If the inputs used to measure the financial assets and liabilities fall within more than one level described above, the categorization is based on the lowest level input that is significant to the fair value measurement of the instrument. Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis Financial assets and liabilities measured at fair value on a recurring basis are summarized below: Fair Value Measurements Using Fair Value Measurements Using Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total ($ in millions) September 30, 2021 December 31, 2020 Assets Investments Foreign government bonds $ — $ 2 $ — $ 2 $ — $ 5 $ — $ 5 Publicly traded equity securities 433 — — 433 780 — — 780 433 2 — 435 780 5 — 785 Other assets (1) U.S. government and agency securities 83 — — 83 84 — — 84 Corporate notes and bonds 4 — — 4 — — — — Publicly traded equity securities 1,482 — — 1,482 1,007 — — 1,007 1,569 — — 1,569 1,091 — — 1,091 Derivative assets (2) Forward exchange contracts — 230 — 230 — 90 — 90 Purchased currency options — 121 — 121 — 37 — 37 Interest rate swaps — 26 — 26 — 55 — 55 — 377 — 377 — 182 — 182 Total assets $ 2,002 $ 379 $ — $ 2,381 $ 1,871 $ 187 $ — $ 2,058 Liabilities Other liabilities Contingent consideration $ — $ — $ 902 $ 902 $ — $ — $ 841 $ 841 Derivative liabilities (2) Forward exchange contracts — 132 — 132 — 505 — 505 Written currency options — 1 — 1 — 20 — 20 — 133 — 133 — 525 — 525 Total liabilities $ — $ 133 $ 902 $ 1,035 $ — $ 525 $ 841 $ 1,366 (1) Investments included in other assets are restricted as to use, including for the payment of benefits under employee benefit plans. (2) The fair value determination of derivatives includes the impact of the credit risk of counterparties to the derivatives and the Company’s own credit risk, the effects of which were not significant. As of September 30, 2021 and December 31, 2020, Cash and cash equivalents included $9.2 billion and $6.8 billion of cash equivalents, respectively (which would be considered Level 2 in the fair value hierarchy). Contingent Consideration Summarized information about the changes in the fair value of liabilities for contingent consideration associated with business acquisitions is as follows: Nine Months Ended September 30, ($ in millions) 2021 2020 January 1 $ 841 $ 767 Additions — 97 Changes in estimated fair value (1) 73 71 Payments — (106) Other (12) — September 30 (2)(3) $ 902 $ 829 (1) Recorded in Cost of sales, Research and development expenses, and Other (income) expense, net . Includes cumulative translation adjustments. (2) Balance at September 30, 2021 includes $289 million recorded as a current liability for amounts expected to be paid within the next 12 months. (3) At September 30, 2021 and December 31, 2020, $747 million and $711 million, respectively, of the liabilities relate to the termination of the Sanofi Pasteur MSD joint venture in 2016. As part of the termination, Merck recorded a liability for contingent future royalty payments of 11.5% on net sales of all Merck products that were previously sold by the joint venture through December 31, 2024. The fair value of this liability is determined utilizing the estimated amount and timing of projected cash flows using a risk-adjusted discount rate of 8% to present value the cash flows. The additions to contingent consideration in 2020 relate to the acquisition of Themis (see Note 3). The payments of contingent consideration in 2020 relate to liabilities recorded in connection with the termination of the Sanofi-Pasteur MSD joint venture in 2016. Other Fair Value Measurements Some of the Company’s financial instruments, such as cash and cash equivalents, receivables and payables, are reflected in the balance sheet at carrying value, which approximates fair value due to their short-term nature. The estimated fair value of loans payable and long-term debt (including current portion) at September 30, 2021, was $29.1 billion compared with a carrying value of $26.4 billion and at December 31, 2020, was $36.0 billion compared with a carrying value of $31.8 billion. Fair value was estimated using recent observable market prices and would be considered Level 2 in the fair value hierarchy. Concentrations of Credit Risk On an ongoing basis, the Company monitors concentrations of credit risk associated with corporate and government issuers of securities and financial institutions with which it conducts business. Credit exposure limits are established to limit a concentration with any single issuer or institution. Cash and investments are placed in instruments that meet high credit quality standards as specified in the Company’s investment policy guidelines. The majority of the Company’s accounts receivable arise from product sales in the U.S., Europe and China and are primarily due from drug wholesalers and retailers, hospitals, government agencies, managed health care providers and pharmacy benefit managers. The Company monitors the financial performance and creditworthiness of its customers so that it can properly assess and respond to changes in their credit profile. The Company also continues to monitor global economic conditions, including the volatility associated with international sovereign economies, and associated impacts on the financial markets and its business. The Company has accounts receivable factoring agreements with financial institutions in certain countries to sell accounts receivable. The Company factored $2.4 billion and $2.1 billion of accounts receivable at September 30, 2021 and December 31, 2020, respectively, under these factoring arrangements, which reduced outstanding accounts receivable. The cash received from the financial institutions is reported within operating activities in the Consolidated Statement of Cash Flows. In certain of these factoring arrangements, for ease of administration, the Company will collect customer payments related to the factored receivables, which it then remits to the financial institutions. The net cash flows relating to these collections are reported as financing activities in the Consolidated Statement of Cash Flows. The cost of factoring such accounts receivable was de minimis . Derivative financial instruments are executed under International Swaps and Derivatives Association master agreements. The master agreements with several of the Company’s financial institution counterparties also include credit support annexes. These annexes contain provisions that require collateral to be exchanged depending on the value of the derivative assets and liabilities, the Company’s credit rating, and the credit rating of the counterparty. Cash collateral received by the Company from various counterparties was $65 million at September 30, 2021. The obligation to return such collateral is recorded in Accrued and other current liabilities . Cash collateral advanced by the Company to counterparties was $36 million at December 31, 2020.

Inventories

Inventories	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consisted of: ($ in millions) September 30, 2021 December 31, 2020 Finished goods $ 1,628 $ 1,610 Raw materials and work in process 6,135 5,949 Supplies 190 146 Total (approximates current cost) 7,953 7,705 Increase (decrease) to LIFO cost 23 (81) $ 7,976 $ 7,624 Recognized as: Inventories $ 5,603 $ 5,554 Other assets 2,373 2,070 Amounts recognized as Other Assets are comprised almost entirely of raw materials and work in process inventories. At September 30, 2021 and December 31, 2020, these amounts included $1.9 billion and $1.8 billion, respectively, of inventories not expected to be sold within one year. In addition, these amounts included $519 million and $279 million at September 30, 2021 and December 31, 2020, respectively, of inventories produced in preparation for product launches.

Goodwill and Intangibles

Goodwill and Intangibles	9 Months Ended
	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	Goodwill and IntangiblesIn connection with the spin-off of Organon (see Note 2), goodwill was reduced by $1.4 billion. Additionally, other intangibles, on a net basis, were reduced by $519 million, including products and products rights of $394 million and licenses of $125 million.

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies The Company is involved in various claims and legal proceedings of a nature considered normal to its business, including product liability, intellectual property, and commercial litigation, as well as certain additional matters including governmental and environmental matters. In the opinion of the Company, it is unlikely that the resolution of these matters will be material to the Company’s financial condition, results of operations or cash flows. Given the nature of the litigation discussed below and the complexities involved in these matters, the Company is unable to reasonably estimate a possible loss or range of possible loss for such matters until the Company knows, among other factors, (i) what claims, if any, will survive dispositive motion practice, (ii) the extent of the claims, including the size of any potential class, particularly when damages are not specified or are indeterminate, (iii) how the discovery process will affect the litigation, (iv) the settlement posture of the other parties to the litigation and (v) any other factors that may have a material effect on the litigation. The Company records accruals for contingencies when it is probable that a liability has been incurred and the amount can be reasonably estimated. These accruals are adjusted periodically as assessments change or additional information becomes available. For product liability claims, a portion of the overall accrual is actuarially determined and considers such factors as past experience, number of claims reported and estimates of claims incurred but not yet reported. Individually significant contingent losses are accrued when probable and reasonably estimable. Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable. The Company’s decision to obtain insurance coverage is dependent on market conditions, including cost and availability, existing at the time such decisions are made. The Company has evaluated its risks and has determined that the cost of obtaining product liability insurance outweighs the likely benefits of the coverage that is available and, as such, has no insurance for most product liabilities. Product Liability Litigation Fosamax As previously disclosed, Merck is a defendant in product liability lawsuits in the U.S. involving Fosamax ( Fosamax Litigation). As of September 30, 2021, approximately 3,470 cases are pending against Merck in either a federal multidistrict litigation (Femur Fracture MDL) or state court. Plaintiffs in the vast majority of these cases generally allege that they sustained femur fractures and/or other bone injuries (Femur Fractures) in association with the use of Fosamax . In March 2014, the Femur Fracture MDL court dismissed with prejudice approximately 650 cases on preemption grounds. Plaintiffs in approximately 515 of those cases appealed that decision to the U.S. Court of Appeals for the Third Circuit (Third Circuit). In March 2017, the Third Circuit issued a decision reversing the Femur Fracture MDL court’s preemption ruling and remanding the appealed cases back to the Femur Fracture MDL court. In May 2019, the U.S. Supreme Court decided that the Third Circuit had incorrectly concluded that the issue of preemption should be resolved by a jury, and accordingly vacated the judgment of the Third Circuit and remanded the proceedings back to the Third Circuit to address the issue in a manner consistent with the Supreme Court’s opinion. In November 2019, the Third Circuit remanded the cases back to the District Court in order to allow that court to determine in the first instance whether the plaintiffs’ state law claims are preempted by federal law under the standards described by the Supreme Court in its opinion. Briefing on the issue is closed, and the parties await the decision of the District Court. Discovery is presently stayed in the Femur Fracture MDL and in the state court in California. As part of the spin-off of Organon, Organon is required to indemnify Merck for all liabilities relating to, arising from, or resulting from the Fosamax Litigation. Januvia/Janumet As previously disclosed, Merck is a defendant in product liability lawsuits in the U.S. involving Januvia and/or Janumet . As of September 30, 2021, Merck is aware of approximately 730 product users alleging that Januvia and/or Janumet caused the development of pancreatic cancer and other injuries. Most claims have been filed in multidistrict litigation before the U.S. District Court for the Southern District of California (MDL). On March 9, 2021, the MDL Court issued an omnibus order granting defendants’ summary judgment motions based on preemption and failure to establish general causation, as well as granting defendants’ motions to exclude plaintiffs’ expert witnesses. The plaintiffs appealed that order. Since that time, more than half of these claims have been dismissed with prejudice as to Merck, and on October 5, 2021, the U.S. Court of Appeals for the Ninth Circuit dismissed the appeal as to Merck and two of its codefendants. Outside of the MDL, the majority of claims have been filed in coordinated proceedings before the Superior Court of California, County of Los Angeles (California State Court). On April 6, 2021, the court in California issued an omnibus order granting defendants’ summary judgment motions and also granting defendants’ motions to exclude plaintiffs’ expert witnesses. As of September 30, 2021, six product users have claims pending against Merck in state courts other than California, including Illinois. In June 2017, the Illinois trial court denied Merck’s motion for summary judgment based on federal preemption. Merck appealed, and the Illinois appellate court affirmed in December 2018. Merck filed a petition for leave to appeal to the Illinois Supreme Court in February 2019. In April 2019, the Illinois Supreme Court stayed consideration of the pending petition to appeal until the U.S. Supreme Court issued its opinion in Merck Sharp & Dohme Corp. v. Albrecht (relating to the Fosamax matter discussed above). Merck filed the opinion in Albrecht with the Illinois Supreme Court in June 2019. The petition for leave to appeal was decided in September 2019, in which the Illinois Supreme Court directed the intermediate appellate court to reconsider its earlier ruling. The Illinois Appellate Court issued a favorable decision concluding, consistent with Albrecht , that preemption presents a legal question to be resolved by the court. In May 2020, the Illinois Appellate Court issued a mandate to the state trial court, which, as of September 30, 2021, had not scheduled a case management conference or otherwise taken action. In addition to the claims noted above, the Company has agreed to toll the statute of limitations for approximately 50 additional claims. The Company intends to continue defending against any remaining lawsuits. Governmental Proceedings As previously disclosed, the Company’s subsidiaries in China have received and may continue to receive inquiries regarding their operations from various Chinese governmental agencies. Some of these inquiries may be related to matters involving other multinational pharmaceutical companies, as well as Chinese entities doing business with such companies. The Company’s policy is to cooperate with these authorities and to provide responses as appropriate. As previously disclosed, from time to time, the Company receives inquiries and is the subject of preliminary investigation activities from competition and other governmental authorities in markets outside the U.S. These authorities may include regulators, administrative authorities, and law enforcement and other similar officials, and these preliminary investigation activities may include site visits, formal or informal requests or demands for documents or materials, inquiries or interviews and similar matters. Certain of these preliminary inquiries or activities may lead to the commencement of formal proceedings. Should those proceedings be determined adversely to the Company, monetary fines and/or remedial undertakings may be required. Commercial and Other Litigation Zetia Antitrust Litigation As previously disclosed, Merck, MSD, Schering Corporation, Schering-Plough Corporation, and MSP Singapore Company LLC (collectively, the Merck Defendants) are defendants in putative class action and opt-out lawsuits filed in 2018 on behalf of direct and indirect purchasers of Zetia alleging violations of federal and state antitrust laws, as well as other state statutory and common law causes of action. The cases have been consolidated for pretrial purposes in a federal multidistrict litigation before Judge Rebecca Beach Smith in the Eastern District of Virginia. In December 2018, the court denied the Merck Defendants’ motions to dismiss or stay the direct purchaser putative class actions pending bilateral arbitration. In August 2019, the district court adopted in full the report and recommendation of the magistrate judge with respect to the Merck Defendants’ motions to dismiss on non-arbitration issues, thereby granting in part and denying in part Merck Defendants’ motions to dismiss. In addition, in June 2019, the representatives of the putative direct purchaser class filed an amended complaint, and in August 2019, retailer opt-out plaintiffs filed an amended complaint. In December 2019, the district court granted the Merck Defendants’ motion to dismiss to the extent the motion sought dismissal of claims for overcharges paid by entities that purchased generic ezetimibe from Par Pharmaceutical, Inc. (Par Pharmaceutical) and dismissed any claims for such overcharges. In November 2019, the direct purchaser plaintiffs and the indirect purchaser plaintiffs filed motions for class certification. In August 2020, the district court granted in part the direct purchasers’ motion for class certification and certified a class of 35 direct purchasers and, in November 2020, the U.S. Court of Appeals for the Fourth Circuit granted the Merck Defendants’ motion for permission to appeal the district court’s order. In August 2021, the Fourth Circuit vacated the district court’s class certification order and remanded for further proceedings consistent with the court’s ruling. In September 2021, the direct purchaser plaintiffs filed a renewed motion for class certification and briefing regarding that motion is pending. In August 2020, the Merck Defendants filed a motion for summary judgment and other motions, and plaintiffs filed a motion for partial summary judgment, and other motions. Those motions are now fully briefed, and the court has heard argument on certain of the motions. The court may hold additional hearings on the other motions. Trial in this matter has been adjourned. Also in August 2020, the magistrate judge recommended that the court grant the motion for class certification filed by the putative indirect purchaser class. The Merck Defendants objected to this report and recommendation. In August 2021, the district court overruled the Merck Defendants’ objections to the report and recommendation and granted certification of a class of indirect purchasers. In September 2021, the Merck Defendants petitioned to appeal the class certification decision to the Fourth Circuit. The Fourth Circuit denied that petition on September 30, 2021. In September 2020, United Healthcare Services, Inc. filed a lawsuit in the U.S. District Court for the District of Minnesota against the Merck Defendants and others (the UHC Action). The UHC Action makes similar allegations as those made in the Zetia class action. In September 2020, the U.S. Judicial Panel on Multidistrict Litigation transferred the case to the Eastern District of Virginia to proceed with the multidistrict Zetia litigation already in progress. Defendants have filed a motion to dismiss. In December 2020, Humana Inc. filed a lawsuit in the Superior Court of the State of California, County of San Francisco, against Merck and others, alleging defendants violated state antitrust laws in multiple states. Also, in December 2020, Centene Corporation and others filed a lawsuit in the Superior Court of the State of California, County of San Francisco, against the same defendants as Humana. Both lawsuits allege similar anticompetitive acts to those alleged in the Zetia class action. In July 2021, the California Court ruled on defendants’ Motion to Quash for lack of personal jurisdiction, granting the motion as to the out-of-state claims against defendants, and ordering limited jurisdictional discovery with regard to the California claims. In September 2021, the parties reached an agreement that Humana and Centene would file their claims in New Jersey federal court, seek a transfer of those claims to the multidistrict Zetia litigation already in progress, and subsequently dismiss the actions previously filed in California. The parties jointly sought a stay of the Superior Court action, pending filing of the federal action. The Superior Court granted the stay on September 17, 2021. Also, on July 16, 2021, Humana and Centene filed actions against the Merck Defendants in New Jersey in the Bergen County Superior Court, re-asserting the claims that were dismissed in their California action. Those complaints have not yet been served, and Humana and Centene have agreed to dismiss those actions once they have filed their complaints in New Jersey federal court. In June 2021, Kaiser Foundation Health Plan, Inc. similarly filed a lawsuit in the Superior Court of the State of California, County of San Francisco, against the same defendants as Humana and Centene. The Kaiser lawsuit alleges similar anticompetitive acts to those alleged in the Zetia class action. The Kaiser action was removed to the U.S. District Court for the Northern District of California on July 16, 2021. In September 2021, the U.S. Judicial Panel on Multidistrict Litigation transferred the case to the Eastern District of Virginia to proceed with the multidistrict Zetia litigation already in progress. Patent Litigation From time to time, generic manufacturers of pharmaceutical products file abbreviated New Drug Applications (NDAs) with the FDA seeking to market generic forms of the Company’s products prior to the expiration of relevant patents owned by the Company. To protect its patent rights, the Company may file patent infringement lawsuits against such generic companies. Similar lawsuits defending the Company’s patent rights may exist in other countries. The Company intends to vigorously defend its patents, which it believes are valid, against infringement by companies attempting to market products prior to the expiration of such patents. As with any litigation, there can be no assurance of the outcomes, which, if adverse, could result in significantly shortened periods of exclusivity for these products and, with respect to products acquired through acquisitions, potentially significant intangible asset impairment charges. Bridion — Between January and November 2020, the Company received multiple Paragraph IV Certification Letters under the Hatch-Waxman Act notifying the Company that generic drug companies have filed applications to the FDA seeking pre-patent expiry approval to sell generic versions of Bridion (sugammadex) Injection. In March, April and December 2020, the Company filed patent infringement lawsuits in the U.S. District Courts for the District of New Jersey and the Northern District of West Virginia against those generic companies. All actions in the District of New Jersey have been consolidated. These lawsuits, which assert one or more patents covering sugammadex and methods of using sugammadex, automatically stay FDA approval of the generic applications until June 2023 or until adverse court decisions, if any, whichever may occur earlier. Mylan Pharmaceuticals Inc., Mylan API US LLC, and Mylan Inc. (Mylan) have filed motions to dismiss in the District of New Jersey for lack of venue and failure to state a claim against certain defendants, and in the Northern District of West Virginia for failure to state a claim against certain defendants. The New Jersey motion has not yet been decided, and the West Virginia action is stayed pending resolution of the New Jersey motion. The Company has settled with three generic companies providing that these generic companies can bring their generic versions of Bridion to the market in January 2026 (which may be delayed by any applicable pediatric exclusivity) or earlier under certain circumstances. Januvia, Janumet, Janumet XR — As previously disclosed, the FDA has granted pediatric exclusivity with respect to Januvia , Janumet , and J anumet XR , which provides a further six months of exclusivity in the U.S. beyond the expiration of all patents listed in the FDA’s Orange Book. Adding this exclusivity to the term of the key patent protection extends exclusivity on these products to January 2023. The Company anticipates that sales of Januvia and Janumet in the U.S. will decline significantly after this loss of market exclusivity. However, Januvia , Janumet , and Janumet XR contain sitagliptin phosphate monohydrate and the Company has another patent covering certain phosphate salt and polymorphic forms of sitagliptin (2027 salt/polymorph patent), which, if determined to be valid, would preclude generic manufacturers from making sitagliptin phosphate salt and polymorphic forms until 2027 with the expiration of that patent, plus pediatric exclusivity. In 2019, Par Pharmaceutical filed suit against the Company in the U.S. District Court for the District of New Jersey, seeking a declaratory judgment of invalidity of the 2027 salt/polymorph patent. In response, the Company filed a patent infringement lawsuit in the U.S. District Court for the District of Delaware against Par Pharmaceutical and additional companies that also indicated an intent to market generic versions of Januvia , Janumet , and Janumet XR following expiration of key patent protection, but prior to the expiration of the 2027 salt/polymorph patent, and a later granted patent owned by the Company covering the Janumet formulation where its term plus the pediatric exclusivity ends in 2029. The Company also filed a patent infringement lawsuit against Mylan in the Northern District of West Virginia. The Judicial Panel on Multidistrict Litigation entered an order transferring the Company’s lawsuit against Mylan to the U.S. District Court for the District of Delaware for coordinated and consolidated pretrial proceedings with the other cases pending in that district. Prior to the beginning of the October 2021 trial in the U.S. District Court for the District of Delaware on invalidity issues, the Company settled with all defendants scheduled to participate in that trial. In the Company’s case against Mylan, the U.S. District Court for the Northern District of West Virginia has scheduled a five-day bench trial in December 2021. In total, the Company has settled with 16 generic companies providing that these generic companies can bring their generic versions of Januvia and Janumet to the market in May 2026 or earlier under certain circumstances, and their generic versions of Janumet XR to the market in July 2026 or earlier under certain circumstances. Additionally, in 2019, Mylan filed a petition for Inter Partes Review (IPR) at the U.S. Patent and Trademark Office (USPTO) seeking invalidity of some, but not all, of the claims of the 2027 salt/polymorph patent. The USPTO instituted IPR proceedings in May 2020, finding a reasonable likelihood that the challenged claims are not valid. A trial was held in February 2021 and a final decision was rendered in May 2021, holding that all of the challenged claims were not invalid. Mylan has appealed the USPTO’s decision to the U.S. Court of Appeals for the Federal Circuit. On March 1, 2021, the Company filed a patent infringement lawsuit in the U.S. District Court for the District of Delaware against Zydus Worldwide DMCC, Zydus Pharmaceuticals (USA) Inc., and Cadila Healthcare Ltd. (collectively, Zydus). In that lawsuit, the Company alleged infringement of the 2027 salt/polymorph patent based on the filing of Zydus’s application seeking approval under 21 U.S.C. § 355(b)(2) of its sitagliptin tablets. The U.S. District Court for the District of Delaware has set a three-day bench trial in this matter beginning on October 31, 2022. In Germany, generic companies have sought the revocation of the Supplementary Protection Certificate (SPC) for Janumet . If the generic companies are successful, Janumet could lose market exclusivity in Germany at the same time as the expiry of Januvia pediatric market exclusivity in September 2022. A hearing was held in June 2021 and the court decided that the SPC for Janumet is invalid, which decision the Company has appealed. Challenges to the Janumet SPC have also occurred in the following European countries: Austria, Czech Republic, Finland, France, Hungary, Italy, Portugal, Romania, Slovakia, and Sweden. Other Litigation There are various other pending legal proceedings involving the Company, principally product liability and intellectual property lawsuits. While it is not feasible to predict the outcome of such proceedings, in the opinion of the Company, either the likelihood of loss is remote or any reasonably possible loss associated with the resolution of such proceedings is not expected to be material to the Company’s financial condition, results of operations or cash flows either individually or in the aggregate. Legal Defense Reserves Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable. Some of the significant factors considered in the review of these legal defense reserves are as follows: the actual costs incurred by the Company; the development of the Company’s legal defense strategy and structure in light of the

Equity

Equity	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Equity	Equity Three Months Ended September 30, Common Stock Other Retained Accumulated Treasury Stock Non- Total ($ and shares in millions except per share amounts) Shares Par Value Shares Cost Balance at July 1, 2020 3,577 $ 1,788 $ 39,373 $ 49,724 $ (6,393) 1,048 $ (56,850) $ 102 $ 27,744 Net income attributable to Merck & Co., Inc. — — — 2,941 — — — — 2,941 Other comprehensive income, net of taxes — — — — 10 — — — 10 Cash dividends declared on common stock ($0.61 per share) — — — (1,558) — — — — (1,558) Share-based compensation plans and other — — 116 — — (1) 35 — 151 Net income attributable to noncontrolling interests — — — — — — — 4 4 Distributions attributable to noncontrolling interests — — — — — — — (22) (22) Balance at September 30, 2020 3,577 $ 1,788 $ 39,489 $ 51,107 $ (6,383) 1,047 $ (56,815) $ 84 $ 29,270 Balance at July 1, 2021 3,577 $ 1,788 $ 44,039 $ 48,777 $ (4,628) 1,044 $ (56,682) $ 94 $ 33,388 Net income attributable to Merck & Co., Inc. — — — 4,567 — — — — 4,567 Other comprehensive income, net of taxes — — — — 38 — — — 38 Cash dividends declared on common stock ($0.65 per share) — — — (1,653) — — — — (1,653) Treasury stock shares purchased — — — — — 8 (583) — (583) Share-based compensation plans and other — — 110 — — — 21 — 131 Net income attributable to noncontrolling interests — — — — — — — 4 4 Distributions attributable to noncontrolling interests — — — — — — — (29) (29) Balance at September 30, 2021 3,577 1,788 44,149 51,691 (4,590) 1,052 (57,244) 69 35,863 Nine Months Ended September 30, Common Stock Other Retained Accumulated Treasury Stock Non- Total ($ and shares in millions except per share amounts) Shares Par Value Shares Cost Balance at January 1, 2020 3,577 $ 1,788 $ 39,660 $ 46,602 $ (6,193) 1,038 $ (55,950) $ 94 $ 26,001 Net income attributable to Merck & Co., Inc. — — — 9,161 — — — — 9,161 Other comprehensive loss, net of taxes — — — — (190) — — — (190) Cash dividends declared on common stock ($1.83 per share) — — — (4,656) — — — — (4,656) Treasury stock shares purchased — — — — — 16 (1,281) — (1,281) Share-based compensation plans and other — — (171) — — (7) 416 — 245 Net income attributable to noncontrolling interests — — — — — — — 12 12 Distributions attributable to noncontrolling interests — — — — — — — (22) (22) Balance at September 30, 2020 3,577 1,788 39,489 51,107 (6,383) 1,047 (56,815) 84 29,270 Balance at January 1, 2021 3,577 $ 1,788 $ 39,588 $ 47,362 $ (6,634) 1,047 $ (56,787) $ 87 $ 25,404 Net income attributable to Merck & Co., Inc. — — — 9,291 — — — — 9,291 Other comprehensive income, net of taxes — — — — 1,595 — — — 1,595 Cash dividends declared on common stock ($1.95 per share) — — — (4,962) — — — — (4,962) Treasury stock shares purchased — — — — — 11 (822) — (822) Spin-off of Organon & Co. — — 4,643 — 449 — — (1) 5,091 Share-based compensation plans and other — — (82) — — (6) 365 — 283 Net income attributable to noncontrolling interests — — — — — — — 12 12 Distributions attributable to noncontrolling interests — — — — — — — (29) (29) Balance at September 30, 2021 3,577 1,788 44,149 51,691 (4,590) 1,052 (57,244) 69 35,863

Pension and Other Postretiremen

Pension and Other Postretirement Benefit Plans	9 Months Ended
	Sep. 30, 2021
Retirement Benefits [Abstract]
Pension and Other Postretirement Benefit Plans	Pension and Other Postretirement Benefit Plans The Company has defined benefit pension plans covering eligible employees in the U.S. and in certain of its international subsidiaries. The net periodic benefit cost of such plans (including certain costs reported as part of discontinued operations) consisted of the following components: Three Months Ended Nine Months Ended 2021 2020 2021 2020 ($ in millions) U.S. International U.S. International U.S. International U.S. International Service cost $ 104 $ 75 $ 96 $ 76 $ 302 $ 254 $ 270 $ 222 Interest cost 102 33 107 35 305 92 323 102 Expected return on plan assets (188) (105) (193) (104) (568) (313) (581) (309) Amortization of unrecognized prior service credit (9) (3) (12) (3) (29) (12) (37) (9) Net loss amortization 75 32 75 32 218 110 228 94 Termination benefits 2 — 1 1 54 3 5 2 Curtailments (1) — 1 — 15 (27) 4 (1) Settlements 139 — 2 — 139 2 11 2 $ 224 $ 32 $ 77 $ 37 $ 436 $ 109 $ 223 $ 103 The Company provides medical benefits, principally to its eligible U.S. retirees and similar benefits to their dependents, through its other postretirement benefit plans. The net credit of such plans consisted of the following components: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Service cost $ 11 $ 13 $ 37 $ 39 Interest cost 12 14 34 43 Expected return on plan assets (20) (19) (59) (56) Amortization of unrecognized prior service credit (16) (18) (48) (54) Net gain amortization (12) (5) (30) (13) Termination benefits — — 37 — Curtailments (1) — (29) (1) $ (26) $ (15) $ (58) $ (42) Net periodic benefit cost (credit) for pension and other postretirement benefit plans in the first nine months of 2021 includes expenses for curtailments, settlements and termination benefits provided to certain employees in connection with the spin-off of Organon. In connection with restructuring actions (see Note 5), termination charges were recorded on pension plans related to expanded eligibility for certain employees e x iting Merck. Also, in connection with these restructuring actions, curtailments and settlements were recorded on pension plans. In addition, lump sum payments to U.S. pension plan participants triggered a partial settlement resulting in a charge of approximately $125 million in the third quarter and first nine months of 2021. This partial settlement triggered a remeasurement of some of the Company’s U.S. pension plans. This remeasurement, which was calculated using discount rates and asset values as of September 30, 2021, resulted in a net increase of $160 million to net pension liabilities and also resulted in a related adjustment to AOCL . The components of net periodic benefit cost (credit) other than the service cost component are included in Other (income) expense, net (see Note 12), with the exception of certain amounts for termination benefits, curtailments and settlements, which are recorded in Restructuring costs if the event giving rise to the termination benefits, curtailment or settlement is related to restructuring actions or in Income from Discontinued Operations, Net of Taxes and Amounts Attributable to Noncontrolling Interests if related to the spin-off of Organon (each as noted above). The transfer of employees to Organon in connection with the spin-off triggered remeasurements of some of the Company’s pension plans. These remeasurements, which were calculated using discount rates and asset values as of the date of the spin-off, resulted in a $1.7 billion reduction to net pension liabilities primarily due to higher discount rates. In addition, $99 million of net pension liabilities were transferred to Organon. The remeasurements and plan transfers also resulted in a related adjustment to AOCL

Other (Income) Expense, Net

Other (Income) Expense, Net	9 Months Ended
	Sep. 30, 2021
Other Income and Expenses [Abstract]
Other (Income) Expense, Net	Other (Income) Expense, Net Other (income) expense, net, consisted of: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Interest income $ (7) $ (9) $ (27) $ (48) Interest expense 196 203 597 624 Exchange losses 46 10 202 89 Income from investments in equity securities, net (1) (683) (360) (1,535) (964) Net periodic defined benefit plan cost (credit) other than service cost 40 (88) (159) (259) Other, net (42) (68) (85) (79) $ (450) $ (312) $ (1,007) $ (637) (1) Includes net realized and unrealized gains and losses from investments in equity securities either owned directly or through ownership interests in investment funds. Unrealized gains and losses from investments that are directly owned are determined at the end of the reporting period, while ownership interests in investment funds are accounted for on a one quarter lag. The Company estimates that gains of approximately $540 million will be recorded in the fourth quarter of 2021 from ownership interests in investment funds. Interest paid for the nine months ended September 30, 2021 and 2020 was $570 million and $605 million, respectively.

Taxes on Income

Taxes on Income	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Taxes on Income	Taxes on Income The effective income tax rates from continuing operations were 13.2% and 14.0% for the third quarter of 2021 and 2020, respectively, and 14.4% and 15.1% for the first nine months of 2021 and 2020, respectively. The effective tax rates from continuing operations in the third quarter and first nine months of 2021 reflect the beneficial impact of the settlement of a foreign tax matter. The effective income tax rate from continuing operations for the first nine months of 2021 reflects the unfavorable effect of a charge for the acquisition of Pandion for which no tax benefit was recognized, as well as a net tax benefit of $207 million related to the settlement of certain federal income tax matters as discussed below. In the first quarter of 2021, the Internal Revenue Service (IRS) concluded its examinations of Merck’s 2015-2016 U.S. federal income tax returns. As a result, the Company was required to make a payment of $190 million (of which $172 million related to Merck continuing operations and $18 million related to Organon discontinued operations). The Company’s reserves for unrecognized tax benefits for the years under examination exceeded the adjustments relating to this examination period and therefore the Company recorded a $236 million net tax benefit in the first nine months of 2021 (of which $207 million related to Merck continuing operations and $29 million related to Organon discontinued operations). This net benefit reflects reductions in reserves for unrecognized tax benefits and other related liabilities for tax positions relating to the years that were under examination.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The calculations of earnings per share are as follows: Three Months Ended Nine Months Ended ($ and shares in millions except per share amounts) 2021 2020 2021 2020 Net Income from Continuing Operations Attributable to Merck & Co., Inc. $ 4,567 $ 2,324 $ 8,525 $ 7,136 Income from Discontinued Operations, Net of Taxes and Amounts Attributable to Noncontrolling Interests — 617 766 2,025 Net Income Attributable to Merck & Co., Inc. $ 4,567 $ 2,941 $ 9,291 $ 9,161 Average common shares outstanding 2,530 2,529 2,531 2,530 Common shares issuable (1) 6 9 8 11 Average common shares outstanding assuming dilution 2,536 2,538 2,539 2,541 Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders: Income from Continuing Operations $ 1.81 $ 0.92 $ 3.37 $ 2.82 Income from Discontinued Operations — 0.24 0.30 0.80 Net Income $ 1.81 $ 1.16 $ 3.67 $ 3.62 Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders: Income from Continuing Operations $ 1.80 $ 0.92 $ 3.36 $ 2.81 Income from Discontinued Operations — 0.24 0.30 0.80 Net Income $ 1.80 $ 1.16 $ 3.66 $ 3.61 (1) Issuable primarily under share-based compensation plans.

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss) Changes in each component of other comprehensive income (loss) are as follows: Three Months Ended September 30, ($ in millions) Derivatives Investments Employee Foreign Currency Accumulated Other Balance July 1, 2020, net of taxes $ 15 $ — $ (4,162) $ (2,246) $ (6,393) Other comprehensive income (loss) before reclassification adjustments, pretax (195) — 2 50 (143) Tax 41 — 1 35 77 Other comprehensive income (loss) before reclassification adjustments, net of taxes (154) — 3 85 (66) Reclassification adjustments, pretax 22 (1) — 72 (3) — 94 Tax (5) — (13) — (18) Reclassification adjustments, net of taxes 17 — 59 — 76 Other comprehensive income (loss), net of taxes (137) — 62 85 10 Balance September 30, 2020, net of taxes $ (122) $ — $ (4,100) $ (2,161) $ (6,383) Balance July 1, 2021, net of taxes $ (26) $ — $ (3,028) $ (1,574) $ (4,628) Other comprehensive income (loss) before reclassification adjustments, pretax 72 — (24) (96) (48) Tax (16) — 16 12 12 Other comprehensive income (loss) before reclassification adjustments, net of taxes 56 — (8) (84) (36) Reclassification adjustments, pretax 36 (1) — 68 (3) — 104 Tax (8) — (22) — (30) Reclassification adjustments, net of taxes 28 — 46 — 74 Other comprehensive income (loss), net of taxes 84 — 38 (84) 38 Balance September 30, 2021, net of taxes $ 58 $ — $ (2,990) $ (1,658) $ (4,590) Nine Months Ended September 30, ($ in millions) Derivatives Investments Employee Foreign Currency Accumulated Other Balance January 1, 2020, net of taxes $ 31 $ 18 $ (4,261) $ (1,981) $ (6,193) Other comprehensive income (loss) before reclassification adjustments, pretax (126) 3 (19) (220) (362) Tax 27 — 12 40 79 Other comprehensive income (loss) before reclassification adjustments, net of taxes (99) 3 (7) (180) (283) Reclassification adjustments, pretax (68) (1) (21) (2) 210 (3) — 121 Tax 14 — (42) — (28) Reclassification adjustments, net of taxes (54) (21) 168 — 93 Other comprehensive income (loss), net of taxes (153) (18) 161 (180) (190) Balance September 30, 2020, net of taxes $ (122) $ — $ (4,100) $ (2,161) $ (6,383) Balance January 1, 2021, net of taxes $ (266) $ — $ (4,540) $ (1,828) $ (6,634) Other comprehensive income (loss) before reclassification adjustments, pretax 193 — 1,739 (167) 1,765 Tax (41) — (385) (84) (510) Other comprehensive income (loss) before reclassification adjustments, net of taxes 152 — 1,354 (251) 1,255 Reclassification adjustments, pretax 218 (1) — 210 (3) — 428 Tax (46) — (42) — (88) Reclassification adjustments, net of taxes 172 — 168 — 340 Other comprehensive income (loss), net of taxes 324 — 1,522 (251) 1,595 Spin-off of Organon (see Note 2) — — 28 421 449 Balance September 30, 2021, net of taxes $ 58 $ — $ (2,990) $ (1,658) $ (4,590) (1) Primarily relates to foreign currency cash flow hedges that were reclassified from AOCL to Sales . (2) Represents net realized gains on the sales of available-for-sale debt securities that were reclassified from AOCL to Other (income) expense, net . (3) Includes net amortization of prior service cost and actuarial gains and losses included in net periodic benefit cost (see Note 11).

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting 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. 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. A large component of pediatric and adolescent vaccine sales are made to the U.S. Centers for Disease Control and Prevention Vaccines for Children program, which is funded by the U.S. government. Additionally, the Company sells vaccines to the Federal government for placement into vaccine stockpiles. 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. 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. Sales of the Company’s products were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 ($ in millions) U.S. Int’l Total U.S. Int’l Total U.S. Int’l Total U.S. Int’l Total Pharmaceutical: Oncology Keytruda $ 2,580 $ 1,954 $ 4,534 $ 2,157 $ 1,559 $ 3,715 $ 7,108 $ 5,501 $ 12,609 $ 6,106 $ 4,281 $ 10,387 Alliance revenue - Lynparza (1) 129 117 246 107 89 196 371 350 721 297 223 519 Alliance revenue - Lenvima (1) 114 74 188 82 60 142 287 211 498 270 152 421 Vaccines Gardasil/Gardasil 9 839 1,154 1,993 579 608 1,187 1,605 2,539 4,144 1,209 1,732 2,941 ProQuad/M-M-R II /Varivax 537 125 661 437 139 576 1,255 371 1,626 1,033 356 1,390 Pneumovax 23 181 97 277 276 99 375 354 247 600 478 270 748 RotaTeq 135 92 227 114 96 210 364 229 593 355 246 601 Vaqta 32 16 48 32 19 51 80 58 138 79 60 139 Hospital Acute Care Bridion 181 188 369 162 157 320 545 551 1,096 412 431 843 Prevymis 39 57 96 32 46 77 111 159 270 87 113 200 Noxafil 19 45 64 13 66 79 48 149 197 27 220 247 Primaxin — 69 70 1 73 74 — 194 194 2 187 189 Cancidas 1 56 56 1 49 50 4 164 168 2 147 148 Invanz (2) 55 53 1 50 51 (2) 159 157 7 152 159 Zerbaxa (1) (1) (2) 20 23 43 (5) (6) (11) 57 54 112 Immunology Simponi — 203 203 — 209 209 — 619 619 — 615 615 Remicade — 73 73 — 82 82 — 233 233 — 242 242 Neuroscience Belsomra 23 58 81 18 63 81 56 183 238 67 177 244 Virology Isentress/Isentress HD 77 112 189 92 113 205 222 368 590 243 403 646 Cardiovascular Alliance revenue-Adempas/Verquvo (2) 73 27 100 78 5 83 222 26 248 200 16 216 Adempas — 59 59 — 55 55 — 188 188 — 167 167 Diabetes Januvia 365 487 852 342 479 821 997 1,448 2,445 1,110 1,339 2,449 Janumet 86 401 487 105 400 506 244 1,205 1,449 361 1,138 1,499 Other pharmaceutical (3) 262 308 572 193 333 526 745 957 1,704 706 969 1,675 Total Pharmaceutical segment sales 5,670 5,826 11,496 4,842 4,872 9,714 14,611 16,103 30,714 13,108 13,690 26,797 Animal Health: Livestock 190 675 864 165 593 758 508 1,996 2,503 448 1,697 2,145 Companion Animals 277 276 553 234 228 462 855 948 1,804 676 714 1,390 Total Animal Health segment sales 467 951 1,417 399 821 1,220 1,363 2,944 4,307 1,124 2,411 3,535 Other segment sales (4) — — — — — — — — — 23 — 23 Total segment sales 6,137 6,777 12,913 5,241 5,693 10,934 15,974 19,047 35,021 14,255 16,101 30,355 Other (5) 139 101 241 9 (14) (5) 192 (30) 162 46 168 215 $ 6,276 $ 6,878 $ 13,154 $ 5,250 $ 5,679 $ 10,929 $ 16,166 $ 19,017 $ 35,183 $ 14,301 $ 16,269 $ 30,570 U.S. plus international may not equal total due to rounding. (1) Alliance revenue represents Merck’s share of profits, which are product sales net of cost of sales and commercialization costs (see Note 4). (2) Alliance revenue represents Merck’s share of profits from sales in Bayer’s marketing territories, which are product sales net of cost of sales and commercialization costs (see Note 4). (3) Other pharmaceutical primarily reflects sales of other human health pharmaceutical products, including products within the franchises not listed separately. (4) Represents sales for the Healthcare Services segment. All the businesses in the Healthcare Services segment were fully divested in the first quarter of 2020. (5) Other is primarily comprised of miscellaneous corporate revenues, including revenue hedging activities, as well as third-party manufacturing sales. Other for the three and nine months ended September 30, 2021 also includes $135 million and $185 million, respectively, related to the achievement of milestones for an out-licensed product that triggered contingent payments to Merck. Product sales are recorded net of the provision for discounts, including chargebacks, which are customer discounts that occur when a contracted customer purchases through an intermediary wholesale purchaser, and rebates that are owed based upon definitive contractual agreements or legal requirements with private sector and public sector (Medicaid and Medicare Part D) benefit providers, after the final dispensing of the product by a pharmacy to a benefit plan participant. These discounts, in the aggregate, reduced U.S. sales by $3.1 billion and $2.9 billion for the three months ended September 30, 2021 and 2020, respectively, and $9.1 billion and $8.3 billion for the nine months ended September 30, 2021 and 2020, respectively. Consolidated sales by geographic area where derived are as follows: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 United States $ 6,276 $ 5,250 $ 16,166 $ 14,301 Europe, Middle East and Africa 3,342 2,946 9,912 8,537 China 1,307 791 3,004 2,060 Japan 638 671 1,929 1,875 Asia Pacific (other than China and Japan) 613 545 1,782 1,560 Latin America 599 499 1,631 1,374 Other 379 227 759 863 $ 13,154 $ 10,929 $ 35,183 $ 30,570 A reconciliation of segment profits to Income from Continuing Operations Before Taxes is as follows: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Segment profits: Pharmaceutical segment $ 8,606 $ 7,026 $ 22,450 $ 19,235 Animal Health segment 505 459 1,629 1,347 Other segment — (1) — 1 Total segment profits 9,111 7,484 24,079 20,583 Other profits 141 (28) 29 135 Unallocated: Interest income 7 9 27 48 Interest expense (196) (203) (597) (624) Amortization (360) (406) (1,231) (1,393) Depreciation (358) (367) (1,031) (1,105) Research and development (2,312) (3,231) (8,775) (7,251) Restructuring costs (107) (113) (487) (265) Other unallocated, net (660) (439) (2,044) (1,720) $ 5,266 $ 2,706 $ 9,970 $ 8,408 Pharmaceutical segment profits are comprised of segment sales less standard costs, as well as selling, general and administrative expenses directly incurred by the segment. Animal Health segment profits are comprised of segment sales, less all cost of sales, as well as selling, general and administrative expenses and research and development costs directly incurred by the segment. For internal management reporting presented to the chief operating decision maker, Merck does not allocate the remaining cost of sales not included in segment profits as described above, research and development expenses incurred in Merck Research Laboratories, the Company’s research and development division that focuses on human health-related activities, or general and administrative expenses, nor the cost of financing these activities. Separate divisions maintain responsibility for monitoring and managing these costs, including depreciation related to fixed assets utilized by these divisions and, therefore, they are not included in segment profits. In addition, costs related to restructuring activities, as well as the amortization of intangible assets and purchase accounting adjustments are not allocated to segments. Other profits are primarily comprised of miscellaneous corporate profits, as well as operating profits related to third-party manufacturing sales. Other unallocated, net, includes expenses from corporate and manufacturing cost centers, goodwill and other intangible asset impairment charges, gains or losses on sales of businesses, expense or income related to changes in the estimated fair value measurement of liabilities for contingent consideration, and other miscellaneous income or expense items.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of PresentationThe accompanying unaudited condensed consolidated financial statements of Merck & Co., Inc. (Merck or the Company) have been prepared pursuant to the rules and regulations for reporting on Form 10-Q. Accordingly, certain information and disclosures required by accounting principles generally accepted in the United States (U.S.) (GAAP) for complete consolidated financial statements are not included herein. These interim statements should be read in conjunction with the audited financial statements and notes thereto included in Merck’s Form 10-K filed on February 25, 2021.The results of operations of any interim period are not necessarily indicative of the results of operations for the full year. In the Company’s opinion, all adjustments necessary for a fair statement of these interim statements have been included and are of a normal and recurring nature.
Recently Adopted Accounting Standards and Recently Issued Accounting Standards Not Yet Adopted	Recently Adopted Accounting Standards In December 2019, the Financial Accounting Standards Board (FASB) issued amended guidance on the accounting and reporting of income taxes. The guidance is intended to simplify the accounting for income taxes by removing exceptions related to certain intraperiod tax allocations and deferred tax liabilities, clarifying guidance primarily related to evaluating the step-up tax basis for goodwill in a business combination, and reflecting enacted changes in tax laws or rates in the annual effective tax rate. The Company adopted the new guidance effective January 1, 2021. There was no impact to the Company’s consolidated financial statements upon adoption. In January 2020, the FASB issued new guidance intended to clarify certain interactions between accounting standards related to equity securities, equity method investments and certain derivatives. The guidance addresses accounting for the transition into and out of the equity method of accounting and measuring certain purchased options and forward contracts to acquire investments. The Company adopted the new guidance effective January 1, 2021. There was no impact to the Company’s consolidated financial statements upon adoption. Recently Issued Accounting Standards Not Yet Adopted In March 2020, the FASB issued optional guidance to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting and subsequently issued clarifying amendments. The guidance provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions that reference the London Interbank Offered Rate (LIBOR) or another reference rate expected to be discontinued because of reference rate reform. The optional guidance is effective upon issuance and can be applied on a prospective basis at any time between January 1, 2020 through December 31, 2022. The Company is currently evaluating the impact of adoption on its consolidated financial statements. In August 2020, the FASB issued amended guidance on the accounting for convertible instruments and contracts in an entity’s own equity. The guidance removes the separation model for convertible debt instruments and preferred stock, amends requirements for conversion options to be classified in equity as well as amends diluted earnings per share (EPS) calculations for certain convertible debt instruments. The amended guidance is effective for interim and annual periods in 2022. Early adoption is permitted. The application of the amendments in the new guidance are to be applied either on a modified retrospective or a retrospective basis. The Company is currently evaluating the impact of adoption on its consolidated financial statements.
Legal Costs	Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable.

Spin-Off of Organon & Co. (Tabl

Spin-Off of Organon & Co. (Tables)	9 Months Ended
	Sep. 30, 2021
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations	Details of Income from Discontinued Operations, Net of Taxes and Amounts Attributable to Noncontrolling Interests are as follows: Three Months Ended Nine Months Ended ($ in millions) 2020 2021 (1) 2020 Sales $ 1,622 $ 2,512 $ 4,911 Costs, Expenses and Other Cost of sales 468 789 1,362 Selling, general and administrative 390 877 1,046 Research and development 41 103 113 Restructuring costs 1 1 4 Other (income) expense, net — (15) 7 900 1,755 2,532 Income from discontinued operations before taxes 722 757 2,379 Tax provision (benefit) 103 (12) 343 Income from discontinued operations, net of taxes 619 769 2,036 Less: Income of discontinued operations attributable to noncontrolling interests 2 3 11 Income from discontinued operations, net of taxes and amounts attributable to noncontrolling interests $ 617 $ 766 $ 2,025 (1) Reflects amounts through the June 2, 2021 spin-off date. Details of assets and liabilities of discontinued operations are as follows: ($ in millions) December 31, 2020 Cash and cash equivalents $ 12 Accounts receivable, less allowance for doubtful accounts 1,048 Inventories 756 Other current assets 867 Current assets of discontinued operations $ 2,683 Property, plant and equipment, net $ 986 Goodwill 1,356 Other intangibles, net 503 Other assets 330 Noncurrent Assets of Discontinued Operations $ 3,175 Trade accounts payable $ 267 Accrued and other current liabilities 841 Income taxes payable (22) Total current liabilities of discontinued operations $ 1,086 Deferred income taxes $ 10 Other noncurrent liabilities 176 Noncurrent Liabilities of Discontinued Operations $ 186

Acquisitions, Research Collab_2

Acquisitions, Research Collaborations and License Agreements (Tables)	9 Months Ended
	Sep. 30, 2021
Business Combination and Asset Acquisition [Abstract]
Fair Value of Assets Acquired and Liabilities Assumed	The estimated fair value of assets acquired and liabilities assumed from ArQule is as follows: ($ in millions) January 16, 2020 Cash and cash equivalents $ 145 IPR&D MK-1026 (formerly ARQ 531) (1) 2,280 Licensing arrangement for ARQ 087 80 Deferred income tax liabilities (361) Other assets and liabilities, net 34 Total identifiable net assets 2,178 Goodwill (2) 512 Consideration transferred $ 2,690 (1) The estimated fair value of the identifiable intangible asset related to IPR&D was determined using an income approach. The future net cash flows were discounted to present value utilizing a discount rate of 12.5%. Actual cash flows are likely to be different than those assumed. (2) The goodwill was allocated to the Pharmaceutical segment and is not deductible for tax purposes.

Collaborative Arrangements (Tab

Collaborative Arrangements (Tables)	9 Months Ended
	Sep. 30, 2021
Collaborative Arrangements [Abstract]
Collaboration Arrangements	Summarized financial information related to this collaboration is as follows: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Alliance revenue - Lynparza $ 246 $ 196 $ 721 $ 519 Alliance revenue - Koselugo 6 3 20 3 Total alliance revenue $ 252 $ 199 $ 741 $ 522 Cost of sales (1) 42 41 125 205 Selling, general and administrative 44 40 127 112 Research and development 27 20 87 93 ($ in millions) September 30, 2021 December 31, 2020 Receivables from AstraZeneca included in Other current assets $ 248 $ 215 Payables to AstraZeneca included in Accrued and other current liabilities (2) 415 423 (1) Represents amortization of capitalized milestone payments. (2) Includes accrued milestone payments. Summarized financial information related to this collaboration is as follows: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Alliance revenue - Lenvima $ 188 $ 142 $ 498 $ 421 Cost of sales (1) 49 46 143 215 Selling, general and administrative 34 18 88 48 Research and development 43 48 165 168 ($ in millions) September 30, 2021 December 31, 2020 Receivables from Eisai included in Other current assets $ 223 $ 157 Payables to Eisai included in Accrued and other current liabilities (2) 600 335 Payables to Eisai included in Other Noncurrent Liabilities (3) — 600 (1) Represents amortization of capitalized milestone payments. (2) Includes accrued milestone and future option payments. (3) Includes accrued milestone payments. Summarized financial information related to this collaboration is as follows: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Alliance revenue - Adempas/Verquvo $ 100 $ 83 $ 248 $ 216 Net sales of Adempas recorded by Merck 59 55 188 167 Net sales of Verquvo recorded by Merck 2 — 3 — Total sales $ 161 $ 138 $ 439 $ 383 Cost of sales (1) 53 81 328 229 Selling, general and administrative 31 12 84 32 Research and development 16 12 36 53 ($ in millions) September 30, 2021 December 31, 2020 Receivables from Bayer included in Other current assets $ 139 $ 65 Payables to Bayer included in Accrued and other current liabilities (2) 467 — (1) Includes amortization of intangible assets. Amount in the first nine months of 2021 includes $153 million of cumulative amortization as noted above. In addition, cost of sales in all periods now includes Bayer’s share of profits from sales in Merck’s marketing territories. (2) Includes accrued milestone payment.

Restructuring (Tables)

Restructuring (Tables)	9 Months Ended
	Sep. 30, 2021
Restructuring and Related Activities [Abstract]
Charges Related to Restructuring Program Activities by Type of Cost	The following tables summarize the charges related to restructuring program activities by type of cost: Three Months Ended September 30, 2021 Nine Months Ended September 30, 2021 ($ in millions) Separation Accelerated Other Total Separation Accelerated Other Total Cost of sales $ — $ 11 $ 37 $ 48 $ — $ 32 $ 81 $ 113 Selling, general and administrative — 4 1 5 — 8 1 9 Research and development — 7 1 8 — 20 1 21 Restructuring costs 17 — 90 107 310 — 177 487 $ 17 $ 22 $ 129 $ 168 $ 310 $ 60 $ 260 $ 630 Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 ($ in millions) Separation Accelerated Other Total Separation Accelerated Other Total Cost of sales $ — $ 33 $ 5 $ 38 $ — $ 89 $ 42 $ 131 Selling, general and administrative — 15 — 15 — 37 — 37 Research and development — 18 1 19 — 66 1 67 Restructuring costs 61 — 52 113 143 — 122 265 $ 61 $ 66 $ 58 $ 185 $ 143 $ 192 $ 165 $ 500
Charges and Spending Relating to Restructuring Activities by Program	The following table summarizes the charges and spending relating to restructuring program activities for the nine months ended September 30, 2021: ($ in millions) Separation Accelerated Other Total Restructuring reserves January 1, 2021 $ 567 $ — $ 19 $ 586 Expense 310 60 260 630 (Payments) receipts, net (305) — (155) (460) Non-cash activity — (60) (84) (144) Restructuring reserves September 30, 2021 (1) $ 572 $ — $ 40 $ 612

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Effect of Net Investment Hedges on OCI and the Consolidated Statement of Income	The effects of the Company’s net investment hedges on OCI and the Consolidated Statement of Income are shown below: Amount of Pretax (Gain) Loss Recognized in Other Comprehensive Income (1) Amount of Pretax (Gain) Loss Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing Three Months Ended September 30, Nine Months Ended September 30, Three Months Ended September 30, Nine Months Ended September 30, ($ in millions) 2021 2020 2021 2020 2021 2020 2021 2020 Net Investment Hedging Relationships Foreign exchange contracts $ 1 $ 10 $ (27) $ 15 $ (4) $ (4) $ (12) $ (15) Euro-denominated notes (77) 162 (199) 182 — — — — (1) No amounts were reclassified from AOCL into income related to the sale of a subsidiary.
Summary of Interest Rate Swaps Held	At September 30, 2021, the Company was a party to nine pay-floating, receive-fixed interest rate swap contracts designated as fair value hedges of fixed-rate notes in which the notional amounts match the amount of the hedged fixed-rate notes as detailed in the table below. September 30, 2021 ($ in millions) Par Value of Debt Number of Interest Rate Swaps Held Total Swap Notional Amount 2.40% notes due 2022 $ 1,000 4 $ 1,000 2.35% notes due 2022 1,250 5 1,250
Amounts Recorded on Balance Sheet Related to Fair Value Hedges	The table below presents the location of amounts recorded on the Condensed Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges: Carrying Amount of Hedged Liabilities Cumulative Amount of Fair Value Hedging Adjustment Increase (Decrease) Included in the Carrying Amount ($ in millions) September 30, 2021 December 31, 2020 September 30, 2021 December 31, 2020 Loans payable and current portion of long-term debt $ 2,274 $ 1,150 $ 25 $ — Long-Term Debt — 2,301 — 53
Fair Value of Derivatives on a Gross Basis Segregated between those Derivatives that are Designated as Hedging Instruments and those that are Not Designated as Hedging Instruments	Presented in the table below is the fair value of derivatives on a gross basis segregated between those derivatives that are designated as hedging instruments and those that are not designated as hedging instruments: September 30, 2021 December 31, 2020 Fair Value of Derivative U.S. Dollar Fair Value of Derivative U.S. Dollar ($ in millions) Asset Liability Asset Liability Derivatives Designated as Hedging Instruments Balance Sheet Caption Interest rate swap contracts Other current assets $ 26 $ — $ 2,250 $ 1 $ — $ 1,150 Interest rate swap contracts Other Assets — — — 54 — 2,250 Foreign exchange contracts Other current assets 224 — 7,138 12 — 3,183 Foreign exchange contracts Other Assets 45 — 1,469 45 — 2,030 Foreign exchange contracts Accrued and other current liabilities — 15 1,601 — 217 5,049 Foreign exchange contracts Other Noncurrent Liabilities — 1 145 — 1 52 $ 295 $ 16 $ 12,603 $ 112 $ 218 $ 13,714 Derivatives Not Designated as Hedging Instruments Balance Sheet Caption Foreign exchange contracts Other current assets $ 82 $ — $ 6,333 $ 70 $ — $ 7,260 Foreign exchange contracts Accrued and other current liabilities — 117 9,522 — 307 11,810 $ 82 $ 117 $ 15,855 $ 70 $ 307 $ 19,070 $ 377 $ 133 $ 28,458 $ 182 $ 525 $ 32,784
Information on Derivative Positions Subject to Master Netting Arrangements as if they were Presented on a Net Basis	The following table provides information on the Company’s derivative positions subject to these master netting arrangements as if they were presented on a net basis, allowing for the right of offset by counterparty and cash collateral exchanged per the master agreements and related credit support annexes: September 30, 2021 December 31, 2020 ($ in millions) Asset Liability Asset Liability Gross amounts recognized in the condensed consolidated balance sheet $ 377 $ 133 $ 182 $ 525 Gross amounts subject to offset in master netting arrangements not offset in the condensed consolidated balance sheet (120) (120) (156) (156) Cash collateral received/posted (65) — — (36) Net amounts $ 192 $ 13 $ 26 $ 333
Location and Amount of Pretax (Gains) Losses of Derivatives	The table below provides information regarding the location and amount of pretax (gains) losses of derivatives designated in fair value or cash flow hedging relationships (including amounts attributable to discontinued operations): Sales Other (income) expense, net (1) Other comprehensive income (loss) Sales Other (income) expense, net (1) Other comprehensive income (loss) Three Months Ended September 30, Three Months Ended September 30, Three Months Ended September 30, Nine Months Ended September 30, Nine Months Ended September 30, Nine Months Ended September 30, ($ in millions) 2021 2020 2021 2020 2021 2020 2021 2020 2021 2020 2021 2020 Financial Statement Line Items in which Effects of Fair Value or Cash Flow Hedges are Recorded $ 13,154 $ 10,929 $ (450) $ (312) $ 38 $ 10 $ 35,183 $ 30,570 $ (1,007) $ (637) $ 1,595 $ (190) (Gain) loss on fair value hedging relationships Interest rate swap contracts Hedged items — — (9) (14) — — — — (29) 54 — — Derivatives designated as hedging instruments — — (1) — — — — — (1) (76) — — Impact of cash flow hedging relationships Foreign exchange contracts Amount of gain (loss) recognized in OCI on derivatives — — — — 72 (195) — — — — 193 (126) (Decrease) increase in Sales as a result of AOCL reclassifications (36) (23) — — 36 23 (219) 65 — — 219 (65) Interest rate contracts Amount of gain recognized in Other (income) expense, net on derivatives — — — (1) — — — — (2) (3) — — Amount of loss recognized in OCI on derivatives — — — — — (1) — — — — (2) (3) (1) Interest expense is a component of Other (income) expense, net.
Income Statement Effects of Derivatives Not Designated as Hedging Instruments	The table below provides information regarding the income statement effects of derivatives not designated as hedging instruments (including amounts attributable to discontinued operations): Amount of Derivative Pretax (Gain) Loss Recognized in Income Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Derivatives Not Designated as Hedging Instruments Income Statement Caption Foreign exchange contracts (1) Other (income) expense, net $ 18 $ (7) $ 234 $ (138) Foreign exchange contracts (2) Sales (4) 7 6 4 Interest rate contracts (3) Other (income) expense, net — — — 9 Forward contract related to Seagen common stock Research and development — 22 — 22 (1) These derivative contracts primarily mitigate changes in the value of remeasured foreign currency denominated monetary assets and liabilities attributable to changes in foreign currency exchange rates. Amount in the first nine months of 2021 includes a loss on forward exchange contracts entered into in conjunction with the spin-off of Organon. (2) These derivative contracts serve as economic hedges of forecasted transactions. (3) These derivative contracts serve as economic hedges against rising treasury rates.
Information on Investments in Debt and Equity Securities	Information on investments in debt and equity securities is as follows: September 30, 2021 December 31, 2020 Amortized Gross Unrealized Fair Amortized Gross Unrealized Fair ($ in millions) Gains Losses Gains Losses U.S. government and agency securities $ 83 $ — $ — $ 83 $ 84 $ — $ — $ 84 Corporate notes and bonds 4 — — 4 — — — — Foreign government bonds 2 — — 2 5 — — 5 Total debt securities $ 89 $ — $ — $ 89 $ 89 $ — $ — $ 89 Publicly traded equity securities (1) 1,915 1,787 Total debt and publicly traded equity securities $ 2,004 $ 1,876 (1) Unrealized net gains of $90 million and unrealized net losses of $109 million were recorded in Other (income) expense, net on equity securities still held at September 30, 2021 in the third quarter and first nine months of 2021, respectively. Unrealized net gains recorded in Other (income) expense, net on equity securities still held at September 30, 2020 were $43 million and $512 million in the third quarter and first nine months of 2020, respectively.
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	Financial assets and liabilities measured at fair value on a recurring basis are summarized below: Fair Value Measurements Using Fair Value Measurements Using Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total ($ in millions) September 30, 2021 December 31, 2020 Assets Investments Foreign government bonds $ — $ 2 $ — $ 2 $ — $ 5 $ — $ 5 Publicly traded equity securities 433 — — 433 780 — — 780 433 2 — 435 780 5 — 785 Other assets (1) U.S. government and agency securities 83 — — 83 84 — — 84 Corporate notes and bonds 4 — — 4 — — — — Publicly traded equity securities 1,482 — — 1,482 1,007 — — 1,007 1,569 — — 1,569 1,091 — — 1,091 Derivative assets (2) Forward exchange contracts — 230 — 230 — 90 — 90 Purchased currency options — 121 — 121 — 37 — 37 Interest rate swaps — 26 — 26 — 55 — 55 — 377 — 377 — 182 — 182 Total assets $ 2,002 $ 379 $ — $ 2,381 $ 1,871 $ 187 $ — $ 2,058 Liabilities Other liabilities Contingent consideration $ — $ — $ 902 $ 902 $ — $ — $ 841 $ 841 Derivative liabilities (2) Forward exchange contracts — 132 — 132 — 505 — 505 Written currency options — 1 — 1 — 20 — 20 — 133 — 133 — 525 — 525 Total liabilities $ — $ 133 $ 902 $ 1,035 $ — $ 525 $ 841 $ 1,366 (1) Investments included in other assets are restricted as to use, including for the payment of benefits under employee benefit plans. (2) The fair value determination of derivatives includes the impact of the credit risk of counterparties to the derivatives and the Company’s own credit risk, the effects of which were not significant.
Information About the Changes in Liabilities for Contingent Consideration	Summarized information about the changes in the fair value of liabilities for contingent consideration associated with business acquisitions is as follows: Nine Months Ended September 30, ($ in millions) 2021 2020 January 1 $ 841 $ 767 Additions — 97 Changes in estimated fair value (1) 73 71 Payments — (106) Other (12) — September 30 (2)(3) $ 902 $ 829 (1) Recorded in Cost of sales, Research and development expenses, and Other (income) expense, net . Includes cumulative translation adjustments. (2) Balance at September 30, 2021 includes $289 million recorded as a current liability for amounts expected to be paid within the next 12 months. (3) At September 30, 2021 and December 31, 2020, $747 million and $711 million, respectively, of the liabilities relate to the termination of the Sanofi Pasteur MSD joint venture in 2016. As part of the termination, Merck recorded a liability for contingent future royalty payments of 11.5% on net sales of all Merck products that were previously sold by the joint venture through December 31, 2024. The fair value of this liability is determined utilizing the estimated amount and timing of projected cash flows using a risk-adjusted discount rate of 8% to present value the cash flows.

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Inventories	Inventories consisted of: ($ in millions) September 30, 2021 December 31, 2020 Finished goods $ 1,628 $ 1,610 Raw materials and work in process 6,135 5,949 Supplies 190 146 Total (approximates current cost) 7,953 7,705 Increase (decrease) to LIFO cost 23 (81) $ 7,976 $ 7,624 Recognized as: Inventories $ 5,603 $ 5,554 Other assets 2,373 2,070

Equity (Tables)

Equity (Tables)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Schedule of Equity	Three Months Ended September 30, Common Stock Other Retained Accumulated Treasury Stock Non- Total ($ and shares in millions except per share amounts) Shares Par Value Shares Cost Balance at July 1, 2020 3,577 $ 1,788 $ 39,373 $ 49,724 $ (6,393) 1,048 $ (56,850) $ 102 $ 27,744 Net income attributable to Merck & Co., Inc. — — — 2,941 — — — — 2,941 Other comprehensive income, net of taxes — — — — 10 — — — 10 Cash dividends declared on common stock ($0.61 per share) — — — (1,558) — — — — (1,558) Share-based compensation plans and other — — 116 — — (1) 35 — 151 Net income attributable to noncontrolling interests — — — — — — — 4 4 Distributions attributable to noncontrolling interests — — — — — — — (22) (22) Balance at September 30, 2020 3,577 $ 1,788 $ 39,489 $ 51,107 $ (6,383) 1,047 $ (56,815) $ 84 $ 29,270 Balance at July 1, 2021 3,577 $ 1,788 $ 44,039 $ 48,777 $ (4,628) 1,044 $ (56,682) $ 94 $ 33,388 Net income attributable to Merck & Co., Inc. — — — 4,567 — — — — 4,567 Other comprehensive income, net of taxes — — — — 38 — — — 38 Cash dividends declared on common stock ($0.65 per share) — — — (1,653) — — — — (1,653) Treasury stock shares purchased — — — — — 8 (583) — (583) Share-based compensation plans and other — — 110 — — — 21 — 131 Net income attributable to noncontrolling interests — — — — — — — 4 4 Distributions attributable to noncontrolling interests — — — — — — — (29) (29) Balance at September 30, 2021 3,577 1,788 44,149 51,691 (4,590) 1,052 (57,244) 69 35,863 Nine Months Ended September 30, Common Stock Other Retained Accumulated Treasury Stock Non- Total ($ and shares in millions except per share amounts) Shares Par Value Shares Cost Balance at January 1, 2020 3,577 $ 1,788 $ 39,660 $ 46,602 $ (6,193) 1,038 $ (55,950) $ 94 $ 26,001 Net income attributable to Merck & Co., Inc. — — — 9,161 — — — — 9,161 Other comprehensive loss, net of taxes — — — — (190) — — — (190) Cash dividends declared on common stock ($1.83 per share) — — — (4,656) — — — — (4,656) Treasury stock shares purchased — — — — — 16 (1,281) — (1,281) Share-based compensation plans and other — — (171) — — (7) 416 — 245 Net income attributable to noncontrolling interests — — — — — — — 12 12 Distributions attributable to noncontrolling interests — — — — — — — (22) (22) Balance at September 30, 2020 3,577 1,788 39,489 51,107 (6,383) 1,047 (56,815) 84 29,270 Balance at January 1, 2021 3,577 $ 1,788 $ 39,588 $ 47,362 $ (6,634) 1,047 $ (56,787) $ 87 $ 25,404 Net income attributable to Merck & Co., Inc. — — — 9,291 — — — — 9,291 Other comprehensive income, net of taxes — — — — 1,595 — — — 1,595 Cash dividends declared on common stock ($1.95 per share) — — — (4,962) — — — — (4,962) Treasury stock shares purchased — — — — — 11 (822) — (822) Spin-off of Organon & Co. — — 4,643 — 449 — — (1) 5,091 Share-based compensation plans and other — — (82) — — (6) 365 — 283 Net income attributable to noncontrolling interests — — — — — — — 12 12 Distributions attributable to noncontrolling interests — — — — — — — (29) (29) Balance at September 30, 2021 3,577 1,788 44,149 51,691 (4,590) 1,052 (57,244) 69 35,863

Pension and Other Postretirem_2

Pension and Other Postretirement Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2021
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Net Benefit Costs	The Company has defined benefit pension plans covering eligible employees in the U.S. and in certain of its international subsidiaries. The net periodic benefit cost of such plans (including certain costs reported as part of discontinued operations) consisted of the following components: Three Months Ended Nine Months Ended 2021 2020 2021 2020 ($ in millions) U.S. International U.S. International U.S. International U.S. International Service cost $ 104 $ 75 $ 96 $ 76 $ 302 $ 254 $ 270 $ 222 Interest cost 102 33 107 35 305 92 323 102 Expected return on plan assets (188) (105) (193) (104) (568) (313) (581) (309) Amortization of unrecognized prior service credit (9) (3) (12) (3) (29) (12) (37) (9) Net loss amortization 75 32 75 32 218 110 228 94 Termination benefits 2 — 1 1 54 3 5 2 Curtailments (1) — 1 — 15 (27) 4 (1) Settlements 139 — 2 — 139 2 11 2 $ 224 $ 32 $ 77 $ 37 $ 436 $ 109 $ 223 $ 103
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Net Benefit Costs	The Company provides medical benefits, principally to its eligible U.S. retirees and similar benefits to their dependents, through its other postretirement benefit plans. The net credit of such plans consisted of the following components: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Service cost $ 11 $ 13 $ 37 $ 39 Interest cost 12 14 34 43 Expected return on plan assets (20) (19) (59) (56) Amortization of unrecognized prior service credit (16) (18) (48) (54) Net gain amortization (12) (5) (30) (13) Termination benefits — — 37 — Curtailments (1) — (29) (1) $ (26) $ (15) $ (58) $ (42)

Other (Income) Expense, Net (Ta

Other (Income) Expense, Net (Tables)	9 Months Ended
	Sep. 30, 2021
Other Income and Expenses [Abstract]
Other (Income) Expense, Net	Other (income) expense, net, consisted of: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Interest income $ (7) $ (9) $ (27) $ (48) Interest expense 196 203 597 624 Exchange losses 46 10 202 89 Income from investments in equity securities, net (1) (683) (360) (1,535) (964) Net periodic defined benefit plan cost (credit) other than service cost 40 (88) (159) (259) Other, net (42) (68) (85) (79) $ (450) $ (312) $ (1,007) $ (637)

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Calculations of Earnings Per Share	The calculations of earnings per share are as follows: Three Months Ended Nine Months Ended ($ and shares in millions except per share amounts) 2021 2020 2021 2020 Net Income from Continuing Operations Attributable to Merck & Co., Inc. $ 4,567 $ 2,324 $ 8,525 $ 7,136 Income from Discontinued Operations, Net of Taxes and Amounts Attributable to Noncontrolling Interests — 617 766 2,025 Net Income Attributable to Merck & Co., Inc. $ 4,567 $ 2,941 $ 9,291 $ 9,161 Average common shares outstanding 2,530 2,529 2,531 2,530 Common shares issuable (1) 6 9 8 11 Average common shares outstanding assuming dilution 2,536 2,538 2,539 2,541 Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders: Income from Continuing Operations $ 1.81 $ 0.92 $ 3.37 $ 2.82 Income from Discontinued Operations — 0.24 0.30 0.80 Net Income $ 1.81 $ 1.16 $ 3.67 $ 3.62 Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders: Income from Continuing Operations $ 1.80 $ 0.92 $ 3.36 $ 2.81 Income from Discontinued Operations — 0.24 0.30 0.80 Net Income $ 1.80 $ 1.16 $ 3.66 $ 3.61 (1) Issuable primarily under share-based compensation plans.

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Changes in AOCI by Component	Changes in each component of other comprehensive income (loss) are as follows: Three Months Ended September 30, ($ in millions) Derivatives Investments Employee Foreign Currency Accumulated Other Balance July 1, 2020, net of taxes $ 15 $ — $ (4,162) $ (2,246) $ (6,393) Other comprehensive income (loss) before reclassification adjustments, pretax (195) — 2 50 (143) Tax 41 — 1 35 77 Other comprehensive income (loss) before reclassification adjustments, net of taxes (154) — 3 85 (66) Reclassification adjustments, pretax 22 (1) — 72 (3) — 94 Tax (5) — (13) — (18) Reclassification adjustments, net of taxes 17 — 59 — 76 Other comprehensive income (loss), net of taxes (137) — 62 85 10 Balance September 30, 2020, net of taxes $ (122) $ — $ (4,100) $ (2,161) $ (6,383) Balance July 1, 2021, net of taxes $ (26) $ — $ (3,028) $ (1,574) $ (4,628) Other comprehensive income (loss) before reclassification adjustments, pretax 72 — (24) (96) (48) Tax (16) — 16 12 12 Other comprehensive income (loss) before reclassification adjustments, net of taxes 56 — (8) (84) (36) Reclassification adjustments, pretax 36 (1) — 68 (3) — 104 Tax (8) — (22) — (30) Reclassification adjustments, net of taxes 28 — 46 — 74 Other comprehensive income (loss), net of taxes 84 — 38 (84) 38 Balance September 30, 2021, net of taxes $ 58 $ — $ (2,990) $ (1,658) $ (4,590) Nine Months Ended September 30, ($ in millions) Derivatives Investments Employee Foreign Currency Accumulated Other Balance January 1, 2020, net of taxes $ 31 $ 18 $ (4,261) $ (1,981) $ (6,193) Other comprehensive income (loss) before reclassification adjustments, pretax (126) 3 (19) (220) (362) Tax 27 — 12 40 79 Other comprehensive income (loss) before reclassification adjustments, net of taxes (99) 3 (7) (180) (283) Reclassification adjustments, pretax (68) (1) (21) (2) 210 (3) — 121 Tax 14 — (42) — (28) Reclassification adjustments, net of taxes (54) (21) 168 — 93 Other comprehensive income (loss), net of taxes (153) (18) 161 (180) (190) Balance September 30, 2020, net of taxes $ (122) $ — $ (4,100) $ (2,161) $ (6,383) Balance January 1, 2021, net of taxes $ (266) $ — $ (4,540) $ (1,828) $ (6,634) Other comprehensive income (loss) before reclassification adjustments, pretax 193 — 1,739 (167) 1,765 Tax (41) — (385) (84) (510) Other comprehensive income (loss) before reclassification adjustments, net of taxes 152 — 1,354 (251) 1,255 Reclassification adjustments, pretax 218 (1) — 210 (3) — 428 Tax (46) — (42) — (88) Reclassification adjustments, net of taxes 172 — 168 — 340 Other comprehensive income (loss), net of taxes 324 — 1,522 (251) 1,595 Spin-off of Organon (see Note 2) — — 28 421 449 Balance September 30, 2021, net of taxes $ 58 $ — $ (2,990) $ (1,658) $ (4,590) (1) Primarily relates to foreign currency cash flow hedges that were reclassified from AOCL to Sales . (2) Represents net realized gains on the sales of available-for-sale debt securities that were reclassified from AOCL to Other (income) expense, net . (3) Includes net amortization of prior service cost and actuarial gains and losses included in net periodic benefit cost (see Note 11).

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Sales from Products	Sales of the Company’s products were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 ($ in millions) U.S. Int’l Total U.S. Int’l Total U.S. Int’l Total U.S. Int’l Total Pharmaceutical: Oncology Keytruda $ 2,580 $ 1,954 $ 4,534 $ 2,157 $ 1,559 $ 3,715 $ 7,108 $ 5,501 $ 12,609 $ 6,106 $ 4,281 $ 10,387 Alliance revenue - Lynparza (1) 129 117 246 107 89 196 371 350 721 297 223 519 Alliance revenue - Lenvima (1) 114 74 188 82 60 142 287 211 498 270 152 421 Vaccines Gardasil/Gardasil 9 839 1,154 1,993 579 608 1,187 1,605 2,539 4,144 1,209 1,732 2,941 ProQuad/M-M-R II /Varivax 537 125 661 437 139 576 1,255 371 1,626 1,033 356 1,390 Pneumovax 23 181 97 277 276 99 375 354 247 600 478 270 748 RotaTeq 135 92 227 114 96 210 364 229 593 355 246 601 Vaqta 32 16 48 32 19 51 80 58 138 79 60 139 Hospital Acute Care Bridion 181 188 369 162 157 320 545 551 1,096 412 431 843 Prevymis 39 57 96 32 46 77 111 159 270 87 113 200 Noxafil 19 45 64 13 66 79 48 149 197 27 220 247 Primaxin — 69 70 1 73 74 — 194 194 2 187 189 Cancidas 1 56 56 1 49 50 4 164 168 2 147 148 Invanz (2) 55 53 1 50 51 (2) 159 157 7 152 159 Zerbaxa (1) (1) (2) 20 23 43 (5) (6) (11) 57 54 112 Immunology Simponi — 203 203 — 209 209 — 619 619 — 615 615 Remicade — 73 73 — 82 82 — 233 233 — 242 242 Neuroscience Belsomra 23 58 81 18 63 81 56 183 238 67 177 244 Virology Isentress/Isentress HD 77 112 189 92 113 205 222 368 590 243 403 646 Cardiovascular Alliance revenue-Adempas/Verquvo (2) 73 27 100 78 5 83 222 26 248 200 16 216 Adempas — 59 59 — 55 55 — 188 188 — 167 167 Diabetes Januvia 365 487 852 342 479 821 997 1,448 2,445 1,110 1,339 2,449 Janumet 86 401 487 105 400 506 244 1,205 1,449 361 1,138 1,499 Other pharmaceutical (3) 262 308 572 193 333 526 745 957 1,704 706 969 1,675 Total Pharmaceutical segment sales 5,670 5,826 11,496 4,842 4,872 9,714 14,611 16,103 30,714 13,108 13,690 26,797 Animal Health: Livestock 190 675 864 165 593 758 508 1,996 2,503 448 1,697 2,145 Companion Animals 277 276 553 234 228 462 855 948 1,804 676 714 1,390 Total Animal Health segment sales 467 951 1,417 399 821 1,220 1,363 2,944 4,307 1,124 2,411 3,535 Other segment sales (4) — — — — — — — — — 23 — 23 Total segment sales 6,137 6,777 12,913 5,241 5,693 10,934 15,974 19,047 35,021 14,255 16,101 30,355 Other (5) 139 101 241 9 (14) (5) 192 (30) 162 46 168 215 $ 6,276 $ 6,878 $ 13,154 $ 5,250 $ 5,679 $ 10,929 $ 16,166 $ 19,017 $ 35,183 $ 14,301 $ 16,269 $ 30,570 U.S. plus international may not equal total due to rounding. (1) Alliance revenue represents Merck’s share of profits, which are product sales net of cost of sales and commercialization costs (see Note 4). (2) Alliance revenue represents Merck’s share of profits from sales in Bayer’s marketing territories, which are product sales net of cost of sales and commercialization costs (see Note 4). (3) Other pharmaceutical primarily reflects sales of other human health pharmaceutical products, including products within the franchises not listed separately. (4) Represents sales for the Healthcare Services segment. All the businesses in the Healthcare Services segment were fully divested in the first quarter of 2020.
Consolidated Sales by Geographic Area	Consolidated sales by geographic area where derived are as follows: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 United States $ 6,276 $ 5,250 $ 16,166 $ 14,301 Europe, Middle East and Africa 3,342 2,946 9,912 8,537 China 1,307 791 3,004 2,060 Japan 638 671 1,929 1,875 Asia Pacific (other than China and Japan) 613 545 1,782 1,560 Latin America 599 499 1,631 1,374 Other 379 227 759 863 $ 13,154 $ 10,929 $ 35,183 $ 30,570
Reconciliation of Segment Profits to Income before Taxes	A reconciliation of segment profits to Income from Continuing Operations Before Taxes is as follows: Three Months Ended Nine Months Ended ($ in millions) 2021 2020 2021 2020 Segment profits: Pharmaceutical segment $ 8,606 $ 7,026 $ 22,450 $ 19,235 Animal Health segment 505 459 1,629 1,347 Other segment — (1) — 1 Total segment profits 9,111 7,484 24,079 20,583 Other profits 141 (28) 29 135 Unallocated: Interest income 7 9 27 48 Interest expense (196) (203) (597) (624) Amortization (360) (406) (1,231) (1,393) Depreciation (358) (367) (1,031) (1,105) Research and development (2,312) (3,231) (8,775) (7,251) Restructuring costs (107) (113) (487) (265) Other unallocated, net (660) (439) (2,044) (1,720) $ 5,266 $ 2,706 $ 9,970 $ 8,408

Spin-Off of Organon & Co. - Nar

Spin-Off of Organon & Co. - Narrative (Details) shares in Thousands, $ in Millions	Jun. 02, 2021USD ($)shares	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received	$ 9,000
Disposal group, other expense		$ 193	$ 556	$ 483
Disposal group, including discontinued operations, liabilities	5,100
Disposal group, including discontinued operations, debt	9,400
Disposal group, including discontinued operations, goodwill	1,400				$ 1,356
Disposal group, including discontinued operations, property, plant and equipment	981				986
Disposal group, including discontinued operation, cash	929
Disposal group, including discontinued operations, inventory	815				756
Disposal group, including discontinued operations, other intangible assets	519				$ 503
Disposal group, including discontinued operation, other net liabilities	$ 328
Spinoff transaction			5,091
Stock options, converted awards (in shares) | shares	1,900
Accumulated Other Comprehensive Loss
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Spinoff transaction	$ 449		449
Foreign Currency Translation Adjustment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Spinoff transaction	421		421
Employee Benefit Plans
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Spinoff transaction	28		28
Other Paid-In Capital
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Spinoff transaction	$ 4,600		4,643
Restricted Stock Units (RSUs)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Equity instruments other than options, converted awards (in shares) | shares	1,300
Performance Share Units (PSUs)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Equity instruments other than options, converted awards (in shares) | shares	248
Organon & Co.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Stock conversion ratio	0.1
Due from related parties, current			1,400
Due to related parties, current			$ 930
Maximum | Transition services agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Period of continuing involvement after disposal	25 months
Maximum | Manufacturing and supply agreements
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Period of continuing involvement after disposal	10 years
Minimum | Manufacturing and supply agreements
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Period of continuing involvement after disposal	4 years
Organon & Co.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Face amount of debt	$ 9,500

Spin-Off of Organon & Co. - Inc

Spin-Off of Organon & Co. - Income from Discontinued Operations, Net of Taxes and Amounts Attributable to Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Discontinued Operations and Disposal Groups [Abstract]
Sales		$ 1,622	$ 2,512	$ 4,911
Costs, Expenses and Other
Cost of sales		468	789	1,362
Selling, general and administrative		390	877	1,046
Research and development		41	103	113
Restructuring costs		1	1	4
Other (income) expense, net		0	(15)	7
Operating expenses		900	1,755	2,532
Income from discontinued operations before taxes		722	757	2,379
Tax provision (benefit)		103	(12)	343
Income from discontinued operations, net of taxes		619	769	2,036
Less: Income of discontinued operations attributable to noncontrolling interests		2	3	11
Income from Discontinued Operations, Net of Taxes and Amounts Attributable to Noncontrolling Interests	$ 0	$ 617	$ 766	$ 2,025

Spin-Off of Organon & Co. - Ass

Spin-Off of Organon & Co. - Assets and Liabilities of Discontinued Operations (Details) - USD ($) $ in Millions	Sep. 30, 2021	Jun. 02, 2021	Dec. 31, 2020
Discontinued Operations and Disposal Groups [Abstract]
Cash and cash equivalents			$ 12
Accounts receivable, less allowance for doubtful accounts			1,048
Inventories		$ 815	756
Other current assets			867
Current assets of discontinued operations	$ 0		2,683
Property, plant and equipment, net		981	986
Goodwill		1,400	1,356
Other intangibles, net		$ 519	503
Other assets			330
Noncurrent Assets of Discontinued Operations	0		3,175
Trade accounts payable			267
Accrued and other current liabilities			841
Income taxes payable			(22)
Current liabilities of discontinued operations	0		1,086
Deferred income taxes			10
Other noncurrent liabilities			176
Noncurrent Liabilities of Discontinued Operations	$ 0		$ 186

Acquisitions, Research Collab_3

Acquisitions, Research Collaborations and License Agreements - Narrative (Details) $ / shares in Units, € in Millions, shares in Millions, $ in Millions	1 Months Ended										3 Months Ended				9 Months Ended		12 Months Ended
	Apr. 30, 2021USD ($)	Mar. 31, 2021USD ($)	Jan. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Oct. 31, 2020USD ($)	Sep. 30, 2020USD ($)$ / sharesshares	Sep. 30, 2020EUR (€)	Jul. 31, 2020USD ($)	Jun. 30, 2020USD ($)	Jan. 31, 2020USD ($)	Dec. 31, 2021USD ($)$ / shares	Sep. 30, 2021USD ($)	Dec. 31, 2020USD ($)	Sep. 30, 2020USD ($)$ / sharesshares	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)$ / sharesshares	Dec. 31, 2020USD ($)	Jan. 16, 2020USD ($)	Dec. 31, 2019USD ($)
Business Acquisition [Line Items]
Research and development												$ 2,445		$ 3,349	$ 9,177	$ 7,609
Reduction to research and development expenses					$ 6
Contingent consideration				$ 841		$ 829						902	$ 841	829	902	829	$ 841		$ 767
Goodwill				18,882								18,862	18,882		18,862		18,882
Decrease in contingent consideration liability															(73)	(71)
Inventories				5,554								$ 5,603	5,554		5,603		5,554
Pandion Therapeutics
Business Acquisition [Line Items]
Consideration transferred, asset acquisition	$ 1,900
Transaction cost, asset acquisition	147
Research and development															1,700
OncoImmune
Business Acquisition [Line Items]
Consideration transferred, asset acquisition				423
Net assets (liabilities)				(22)									$ (22)				$ (22)
Amount paid for investment				$ 50
Ownership percentage				20.00%									20.00%				20.00%
Value of investment				$ 33									$ 33				$ 33
Premium on shares acquired				17
Research and development expenses																	462
Dunboyne
Business Acquisition [Line Items]
Consideration transferred, asset acquisition						302	€ 256
Net assets (liabilities)						13								13		13
Property, plant and equipment						289								289		289
Research and development
Business Acquisition [Line Items]
Premium on shares acquired						22
COVID-19
Business Acquisition [Line Items]
Charges related to program discontinuation															$ 207
Sentinel
Business Acquisition [Line Items]
Consideration transferred, asset acquisition								$ 410
Inventories								9
Sentinel | Technology Rights
Business Acquisition [Line Items]
Acquired intangible assets								$ 401
Acceleron Pharma Inc. | Forecast
Business Acquisition [Line Items]
Share price in acquisition of business (in dollars per share) | $ / shares											$ 180
Payment to acquire business											$ 11,500
Termination fee to be paid by acquiree in acquisition of business											345
Acceleron Pharma Inc. | Minimum | Forecast
Business Acquisition [Line Items]
Reverse termination fee in acquisition of business											650
Acceleron Pharma Inc. | Maximum | Forecast
Business Acquisition [Line Items]
Reverse termination fee in acquisition of business											$ 750
Pandion Therapeutics
Business Acquisition [Line Items]
Net assets (liabilities)	$ 156
Themis
Business Acquisition [Line Items]
Payment to acquire business									$ 366
Contingent consideration, maximum									740
Contingent consideration									85
In-process research and development									113
Cash and cash equivalents									59
Deferred tax assets									72
Other assets (liabilities), net									(32)
Goodwill									$ 239
Future milestone payments																	450
Themis | COVID-19
Business Acquisition [Line Items]
Impairment charge													90
Decrease in contingent consideration liability													45
ArQule
Business Acquisition [Line Items]
Payment to acquire business										$ 2,700
In-process research and development																		$ 2,280
Cash and cash equivalents																		145
Other assets (liabilities), net																		34
Goodwill																		$ 512
Share-based compensation payments attributable to precombination service										138
Transaction costs										$ 95
Development Milestones | Themis
Business Acquisition [Line Items]
Contingent consideration, maximum				60									60				60
Regulatory Milestones | Themis
Business Acquisition [Line Items]
Contingent consideration, maximum				196									196				196
Sales-Based Milestones | Themis
Business Acquisition [Line Items]
Contingent consideration, maximum				$ 194									$ 194				$ 194
Gilead Sciences | oral and injectable formulations programs | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Business Acquisition [Line Items]
Profit share by counterparty		60.00%
Profit share		40.00%
Gilead Sciences | oral formulation | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Business Acquisition [Line Items]
Profit share by counterparty		65.00%
Profit share		35.00%
Sales threshold		$ 2,000
Gilead Sciences | injectable formulation | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Business Acquisition [Line Items]
Profit share by counterparty		65.00%
Profit share		35.00%
Sales threshold		$ 3,500
Artiva Biotherapeutics, Inc. | Licensing Agreements
Business Acquisition [Line Items]
Upfront and milestone payments			$ 30
Upfront and milestone payments to be made			$ 15
Artiva Biotherapeutics, Inc. | Minimum | Licensing Agreements
Business Acquisition [Line Items]
Royalty rate			7.00%
Artiva Biotherapeutics, Inc. | Maximum | Licensing Agreements
Business Acquisition [Line Items]
Royalty rate			14.00%
Artiva Biotherapeutics, Inc. | Development Milestones | Licensing Agreements
Business Acquisition [Line Items]
Contingent milestone payments collaborative arrangement			$ 217.5
Artiva Biotherapeutics, Inc. | Regulatory Milestones | Licensing Agreements
Business Acquisition [Line Items]
Contingent milestone payments collaborative arrangement			570
Artiva Biotherapeutics, Inc. | Sales-Based Milestones | Licensing Agreements
Business Acquisition [Line Items]
Contingent milestone payments collaborative arrangement			$ 1,050
Seagen
Business Acquisition [Line Items]
Research and development														$ 622		$ 622
Upfront and milestone payments						600
Contingent milestone payments collaborative arrangement						2,600
Amount paid for investment						$ 1,000
Number of shares acquired through equity investment | shares						5								5		5
Share price (in dollars per share) | $ / shares						$ 200								$ 200		$ 200
Seagen | Tukysa
Business Acquisition [Line Items]
Upfront and milestone payments														$ 210		$ 210
Seagen | Tukysa | Minimum
Business Acquisition [Line Items]
Royalty rate						20.00%	20.00%
Seagen | Tukysa | Maximum
Business Acquisition [Line Items]
Royalty rate						33.00%	33.00%
Seagen | Development Milestones
Business Acquisition [Line Items]
Contingent milestone payments collaborative arrangement						$ 850
Seagen | Regulatory Milestones | Tukysa
Business Acquisition [Line Items]
Contingent milestone payments collaborative arrangement						65
Seagen | Sales-Based Milestones
Business Acquisition [Line Items]
Contingent milestone payments collaborative arrangement						$ 1,750
Sentinel | Technology Rights
Business Acquisition [Line Items]
Weighted average useful life of acquired finite-lived intangible assets								15 years

Acquisitions, Research Collab_4

Acquisitions, Research Collaborations and License Agreements - Fair Values of Assets Acquired and Liabilities Assumed (Details) $ in Millions	Sep. 30, 2021USD ($)	Dec. 31, 2020USD ($)	Jan. 16, 2020USD ($)
Business Acquisition [Line Items]
Goodwill	$ 18,862	$ 18,882
ArQule
Business Acquisition [Line Items]
Cash and cash equivalents			$ 145
IPR&D MK-1026 (formerly ARQ 531)			2,280
Licensing arrangement for ARQ 087			80
Deferred income tax liabilities			(361)
Other assets (liabilities), net			34
Total identifiable net assets			2,178
Goodwill			512
Consideration transferred			$ 2,690
ArQule | Measurement Input, Discount Rate
Business Acquisition [Line Items]
Present value discount rate			0.125

Collaborative Arrangements - Na

Collaborative Arrangements - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	Mar. 31, 2021	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amortization			$ 1,231	$ 1,393
Lynparza | Other Noncurrent Assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Finite-lived intangible assets		$ 1,100	1,100
Lenvima | Other Noncurrent Assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Finite-lived intangible assets		1,000	1,000
Verquvo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amortization			153
Verquvo | Other Intangible Assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Finite-lived intangible assets		72	72
Adempas | Other Intangible Assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Finite-lived intangible assets		869	869
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Lynparza
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payments accrued but not yet paid		400	400
Potential future sales-based milestone payments		2,700	2,700
Potential future regulatory milestone payments		1,400	1,400
Eisai
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License option payment related to collaborative arrangement	$ 125
Eisai | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Lenvima
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payments accrued but not yet paid		600	600
Potential future sales-based milestone payments		2,600	2,600
Potential future regulatory milestone payments		50	50
Sales-based milestone payments			$ 200
Eisai | Regulatory Milestones | Lenvima
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Capitalized milestone payment		$ 75
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payments accrued but not yet paid	400
Liabilities	$ 400

Collaborative Arrangements - Fi

Collaborative Arrangements - Financial Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	$ 13,154	$ 10,929	$ 35,183	$ 30,570
Cost of sales	3,450	3,013	9,752	8,589
Selling, general and administrative	2,336	2,060	6,804	6,336
Research and development	2,445	3,349	9,177	7,609
Payables included in Accrued and other liabilities	23,728		23,728		$ 27,327
Other current assets | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	248		248		215
Other current assets | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	223		223		157
Other current assets | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	139		139		65
Accounts Payable and Accrued Liabilities | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Accrued and other liabilities	415		415		423
Accounts Payable and Accrued Liabilities | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Accrued and other liabilities	600		600		335
Accounts Payable and Accrued Liabilities | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Accrued and other liabilities	467		467		0
Other Noncurrent Liabilities | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Other Noncurrent Liabilities	0		0		$ 600
Revenue | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	252	199	741	522
Revenue | AstraZeneca | Collaborative Arrangement | Alliance revenue - Lynparza
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	246	196	721	519
Revenue | AstraZeneca | Collaborative Arrangement | Alliance revenue - Koselugo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	6	3	20	3
Revenue | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	188	142	498	421
Revenue | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	100	83	248	216
Sales	161	138	439	383
Revenue | Bayer AG | Collaborative Arrangement | Adempas
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net sales by Merck	59	55	188	167
Revenue | Bayer AG | Collaborative Arrangement | Verquvo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net sales by Merck	2	0	3	0
Cost of sales | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	42	41	125	205
Cost of sales | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	49	46	143	215
Cost of sales | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	53	81	328	229
Amortization of intangible assets			153
Selling, general and administrative | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	44	40	127	112
Selling, general and administrative | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	34	18	88	48
Selling, general and administrative | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	31	12	84	32
Research and development | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	27	20	87	93
Research and development | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	43	48	165	168
Research and development | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	$ 16	$ 12	$ 36	$ 53

Restructuring - Narrative (Deta

Restructuring - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2021
Restructuring Cost and Reserve [Line Items]
Expected restructuring and related cost	$ 3,000		$ 3,000
Estimate of cumulative pre tax costs that will result in cash outlays			70.00%
Estimate of cumulative pre tax costs that will be noncash			30.00%
Total pretax restructuring costs	168	$ 185	$ 630	$ 500
Cumulative costs since program inception	$ 2,400		$ 2,400
Forecast
Restructuring Cost and Reserve [Line Items]
Expected restructuring and related cost					$ 700

Restructuring - Charges Activit

Restructuring - Charges Activities by Type of Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 168	$ 185	$ 630	$ 500
Separation Costs
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	17	61	310	143
Accelerated Depreciation
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	22	66	60	192
Other
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	129	58	260	165
Cost of sales
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	48	38	113	131
Cost of sales | Separation Costs
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	0	0	0	0
Cost of sales | Accelerated Depreciation
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	11	33	32	89
Cost of sales | Other
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	37	5	81	42
Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	5	15	9	37
Selling, general and administrative | Separation Costs
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	0	0	0	0
Selling, general and administrative | Accelerated Depreciation
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	4	15	8	37
Selling, general and administrative | Other
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	1	0	1	0
Research and development
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	8	19	21	67
Research and development | Separation Costs
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	0	0	0	0
Research and development | Accelerated Depreciation
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	7	18	20	66
Research and development | Other
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	1	1	1	1
Restructuring costs
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	107	113	487	265
Restructuring costs | Separation Costs
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	17	61	310	143
Restructuring costs | Accelerated Depreciation
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	0	0	0	0
Restructuring costs | Other
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 90	$ 52	$ 177	$ 122

Restructuring - Activities by P

Restructuring - Activities by Program (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			$ 586
Expense	$ 168	$ 185	630	$ 500
(Payments) receipts, net			(460)
Non-cash activity			(144)
Restructuring reserve, ending balance	612		612
Separation Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			567
Expense	17	61	310	143
(Payments) receipts, net			(305)
Non-cash activity			0
Restructuring reserve, ending balance	572		572
Accelerated Depreciation
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			0
Expense	22	66	60	192
(Payments) receipts, net			0
Non-cash activity			(60)
Restructuring reserve, ending balance	0		0
Other
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			19
Expense	129	$ 58	260	$ 165
(Payments) receipts, net			(155)
Non-cash activity			(84)
Restructuring reserve, ending balance	$ 40		$ 40

Financial Instruments - Narrati

Financial Instruments - Narrative (Details)	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2021USD ($)interest_rate_swap	Sep. 30, 2021USD ($)interest_rate_swap	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Jan. 31, 2021USD ($)interest_rate_swap
Derivative [Line Items]
Total swap notional amount	$ 28,458,000,000	$ 28,458,000,000		$ 32,784,000,000
Pretax net unrealized gains on derivatives maturing within next 12 months estimated to be reclassified from AOCI to sales		55,000,000
Equity investments without readily determinable fair values	578,000,000	578,000,000	$ 508,000,000
Unrealized gains recognized on investments in equity securities without readily determinable fair value		104,000,000	21,000,000
Unrealized losses recognized on investments in equity securities without readily determinable fair values		1,000,000	$ 3,000,000
Cumulative unrealized gains on investments	229,000,000	229,000,000
Cumulative unrealized losses on investments	7,000,000	7,000,000
Fair value of loans payable and long-term debt, including current portion	29,100,000,000	29,100,000,000		36,000,000,000
Debt, carrying amount	26,400,000,000	26,400,000,000		31,800,000,000
Factored accounts receivable	2,400,000,000			2,100,000,000
Cash collateral received from counterparties	65,000,000	65,000,000		0
Cash collateral advanced to counterparties	0	0		36,000,000
Level 2
Derivative [Line Items]
Cash equivalents	9,200,000,000	9,200,000,000		6,800,000,000
Derivatives Designated as Hedging Instruments
Derivative [Line Items]
Total swap notional amount	12,603,000,000	$ 12,603,000,000		13,714,000,000
Derivatives Designated as Hedging Instruments | Maximum
Derivative [Line Items]
Maximum average period of maturities of contracts in years (less than)		2 years
Derivatives Not Designated as Hedging Instruments
Derivative [Line Items]
Total swap notional amount	$ 15,855,000,000	$ 15,855,000,000		$ 19,070,000,000
Derivatives Not Designated as Hedging Instruments | Maximum
Derivative [Line Items]
Maximum average period of maturities of contracts in years (less than)		1 year
3.875% Notes Due 2021 [Member]
Derivative [Line Items]
Face amount of debt					$ 1,150,000,000
Stated interest rate					3.875%
Interest rate swap contracts
Derivative [Line Items]
Number of interest rate swaps held (in interest rate swaps) | interest_rate_swap	9	9			5
Total swap notional amount					$ 1,150,000,000

Financial Instruments - Effect

Financial Instruments - Effect of Net Investment Hedges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Pretax (Gain) Loss Recognized in Other Comprehensive Income	$ 1	$ 10	$ (27)	$ 15
Foreign exchange contracts | Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Pretax (Gain) Loss Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing	(4)	(4)	(12)	(15)
Euro-denominated notes
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Pretax (Gain) Loss Recognized in Other Comprehensive Income	(77)	162	(199)	182
Euro-denominated notes | Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Pretax (Gain) Loss Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing	$ 0	$ 0	$ 0	$ 0

Financial Instruments - Summary

Financial Instruments - Summary of Interest Rate Swaps Held (Details)	Sep. 30, 2021USD ($)interest_rate_swap	Jan. 31, 2021USD ($)interest_rate_swap	Dec. 31, 2020USD ($)
Derivative [Line Items]
Total swap notional amount	$ 28,458,000,000		$ 32,784,000,000
Interest rate swap contracts
Derivative [Line Items]
Number of Interest Rate Swaps Held (in interest rate swaps) | interest_rate_swap	9	5
Total swap notional amount		$ 1,150,000,000
2.40% notes due 2022 | Interest rate swap contracts
Derivative [Line Items]
Stated interest rate	2.40%
Par Value of Debt	$ 1,000,000,000
Number of Interest Rate Swaps Held (in interest rate swaps) | interest_rate_swap	4
Total swap notional amount	$ 1,000,000,000
2.35% notes due 2022 | Interest rate swap contracts
Derivative [Line Items]
Stated interest rate	2.35%
Par Value of Debt	$ 1,250,000,000
Number of Interest Rate Swaps Held (in interest rate swaps) | interest_rate_swap	5
Total swap notional amount	$ 1,250,000,000

Financial Instruments - Fair Va

Financial Instruments - Fair Value Hedges (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Loans payable and current portion of long-term debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Liabilities	$ 2,274	$ 1,150
Cumulative Amount of Fair Value Hedging Adjustment Increase (Decrease) Included in the Carrying Amount	25	0
Long-Term Debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Carrying Amount of Hedged Liabilities	0	2,301
Cumulative Amount of Fair Value Hedging Adjustment Increase (Decrease) Included in the Carrying Amount	$ 0	$ 53

Financial Instruments - Fair _2

Financial Instruments - Fair Value of Derivatives Segregated between those Derivatives that are Designated as Hedging Instruments and those that are Not Designated as Hedging Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	$ 377	$ 182
Fair Value of Derivative, Liability	133	525
U.S Dollar Notional Amount	28,458	32,784
Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	295	112
Fair Value of Derivative, Liability	16	218
U.S Dollar Notional Amount	12,603	13,714
Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	82	70
Fair Value of Derivative, Liability	117	307
U.S Dollar Notional Amount	15,855	19,070
Interest Rate Contract | Derivatives Designated as Hedging Instruments | Other current assets
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	26	1
U.S Dollar Notional Amount	2,250	1,150
Interest Rate Contract | Derivatives Designated as Hedging Instruments | Other Assets
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset		54
U.S Dollar Notional Amount	0	2,250
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other current assets
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	224	12
U.S Dollar Notional Amount	7,138	3,183
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other Assets
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	45	45
U.S Dollar Notional Amount	1,469	2,030
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Accrued and other current liabilities
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Liability	15	217
U.S Dollar Notional Amount	1,601	5,049
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Liability	1	1
U.S Dollar Notional Amount	145	52
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments | Other current assets
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	82	70
U.S Dollar Notional Amount	6,333	7,260
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments | Accrued and other current liabilities
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Liability	117	307
U.S Dollar Notional Amount	$ 9,522	$ 11,810

Financial Instruments - Informa

Financial Instruments - Information on Derivative Positions Subject to Master Netting Arrangements as if they were Presented on a Net Basis (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross amounts recognized in the consolidated balance sheet, asset	$ 377,000,000	$ 182,000,000
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, asset	(120,000,000)	(156,000,000)
Cash collateral received, asset	(65,000,000)	0
Net amounts, asset	192,000,000	26,000,000
Gross amounts recognized in the consolidated balance sheet, liability	133,000,000	525,000,000
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, liability	(120,000,000)	(156,000,000)
Cash collateral received, liability	0	(36,000,000)
Net amounts, liability	$ 13,000,000	$ 333,000,000

Financial Instruments - Locatio

Financial Instruments - Location and Amount of Pretax (Gains) Losses of Derivatives (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Sales	$ 13,154	$ 10,929	$ 35,183	$ 30,570
Other (income) expense, net	(450)	(312)	(1,007)	(637)
Other comprehensive income (loss)	38	10	1,595	(190)
Interest rate swap contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in OCI on derivatives	0	(1)	(2)	(3)
Interest rate swap contracts | Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	(9)	(14)	(29)	54
Derivatives designated as hedging instruments	(1)	0	(1)	(76)
Amount of gain recognized in Other (income) expense, net on derivatives	0	(1)	(2)	(3)
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in OCI on derivatives	72	(195)	193	(126)
(Decrease) increase in Sales as a result of AOCL reclassifications	36	23	219	(65)
Foreign exchange contracts | Reclassification out of Accumulated Other Comprehensive Income | Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest
Derivative Instruments, Gain (Loss) [Line Items]
Sales	$ (36)	$ (23)	$ (219)	$ 65

Financial Instruments - Income

Financial Instruments - Income Statement Effects on Derivatives Not Designated as Hedging Instruments (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Derivative Pretax (Gain) Loss Recognized in Income	$ (6)
Currency Swap | Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Derivative Pretax (Gain) Loss Recognized in Income		$ 18	$ (7)	$ 234	$ (138)
Foreign Exchange Future | Sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Derivative Pretax (Gain) Loss Recognized in Income		(4)	7	6	4
Interest Rate Contract | Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Derivative Pretax (Gain) Loss Recognized in Income		0	0	0	9
Forward Contracts | Research and development
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Derivative Pretax (Gain) Loss Recognized in Income		$ 0	$ 22	$ 0	$ 22

Financial Instruments - Infor_2

Financial Instruments - Information on Available-for-sale Investments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	$ 89		$ 89		$ 89
Debt securities, unrealized gains	0		0		0
Debt securities, unrealized losses	0		0		0
Debt securities, fair value	89		89		89
Publicly traded equity securities, fair value	1,915		1,915		1,787
Total debt and publicly traded equity securities, fair value	2,004		2,004		1,876
Unrealized net (losses) gains	90	$ 43	(109)	$ 512
U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	83		83		84
Debt securities, unrealized gains	0		0		0
Debt securities, unrealized losses	0		0		0
Debt securities, fair value	83		83		84
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	4		4		0
Debt securities, unrealized gains	0		0		0
Debt securities, unrealized losses	0		0		0
Debt securities, fair value	4		4		0
Foreign government bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	2		2		5
Debt securities, unrealized gains	0		0		0
Debt securities, unrealized losses	0		0		0
Debt securities, fair value	$ 2		$ 2		$ 5

Financial Instruments - Financi

Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Assets
Foreign government bonds	$ 89	$ 89
Publicly traded equity securities	1,915	1,787
Derivative assets	377	182
Liabilities
Contingent consideration	902	841	$ 829	$ 767
Derivative liabilities	133	525
Foreign government bonds
Assets
Foreign government bonds	2	5
U.S. government and agency securities
Assets
Foreign government bonds	83	84
Corporate notes and bonds
Assets
Foreign government bonds	4	0
Fair Value, Measurements, Recurring
Assets
Investments	435	785
Other assets	1,569	1,091
Derivative assets	377	182
Total assets	2,381	2,058
Liabilities
Contingent consideration	902	841
Derivative liabilities	133	525
Total liabilities	1,035	1,366
Fair Value, Measurements, Recurring | Foreign exchange contracts
Assets
Derivative assets	230	90
Liabilities
Derivative liabilities	132	505
Fair Value, Measurements, Recurring | Interest rate swaps
Assets
Derivative assets	26	55
Fair Value, Measurements, Recurring | Currency options
Assets
Derivative assets	121	37
Liabilities
Derivative liabilities	1	20
Fair Value, Measurements, Recurring | Level 1
Assets
Investments	433	780
Other assets	1,569	1,091
Derivative assets	0	0
Total assets	2,002	1,871
Liabilities
Contingent consideration	0	0
Derivative liabilities	0	0
Total liabilities	0	0
Fair Value, Measurements, Recurring | Level 1 | Foreign exchange contracts
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Level 1 | Interest rate swaps
Assets
Derivative assets	0	0
Fair Value, Measurements, Recurring | Level 1 | Currency options
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Level 2
Assets
Investments	2	5
Other assets	0	0
Derivative assets	377	182
Total assets	379	187
Liabilities
Contingent consideration	0	0
Derivative liabilities	133	525
Total liabilities	133	525
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts
Assets
Derivative assets	230	90
Liabilities
Derivative liabilities	132	505
Fair Value, Measurements, Recurring | Level 2 | Interest rate swaps
Assets
Derivative assets	26	55
Fair Value, Measurements, Recurring | Level 2 | Currency options
Assets
Derivative assets	121	37
Liabilities
Derivative liabilities	1	20
Fair Value, Measurements, Recurring | Level 3
Assets
Investments	0	0
Other assets	0	0
Derivative assets	0	0
Total assets	0	0
Liabilities
Contingent consideration	902	841
Derivative liabilities	0	0
Total liabilities	902	841
Fair Value, Measurements, Recurring | Level 3 | Foreign exchange contracts
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Level 3 | Interest rate swaps
Assets
Derivative assets	0	0
Fair Value, Measurements, Recurring | Level 3 | Currency options
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Foreign government bonds
Assets
Foreign government bonds	2	5
Fair Value, Measurements, Recurring | Foreign government bonds | Level 1
Assets
Foreign government bonds	0	0
Fair Value, Measurements, Recurring | Foreign government bonds | Level 2
Assets
Foreign government bonds	2	5
Fair Value, Measurements, Recurring | Foreign government bonds | Level 3
Assets
Foreign government bonds	0	0
Fair Value, Measurements, Recurring | Publicly traded equity securities
Assets
Publicly traded equity securities	433	780
Other assets	1,482	1,007
Fair Value, Measurements, Recurring | Publicly traded equity securities | Level 1
Assets
Publicly traded equity securities	433	780
Other assets	1,482	1,007
Fair Value, Measurements, Recurring | Publicly traded equity securities | Level 2
Assets
Publicly traded equity securities	0	0
Other assets	0	0
Fair Value, Measurements, Recurring | Publicly traded equity securities | Level 3
Assets
Publicly traded equity securities	0	0
Other assets	0	0
Fair Value, Measurements, Recurring | U.S. government and agency securities
Assets
Other assets	83	84
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 1
Assets
Other assets	83	84
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 2
Assets
Other assets	0	0
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 3
Assets
Other assets	0	0
Fair Value, Measurements, Recurring | Corporate notes and bonds
Assets
Other assets	4	0
Fair Value, Measurements, Recurring | Corporate notes and bonds | Level 1
Assets
Other assets	4	0
Fair Value, Measurements, Recurring | Corporate notes and bonds | Level 2
Assets
Other assets	0	0
Fair Value, Measurements, Recurring | Corporate notes and bonds | Level 3
Assets
Other assets	$ 0	$ 0

Financial Instruments - Infor_3

Financial Instruments - Information About Changes in Liabilities for Contingent Consideration (Details) $ in Millions	3 Months Ended	9 Months Ended
	Dec. 31, 2020USD ($)	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	$ 829	$ 841	$ 767
Additions		0	97
Changes in estimated fair value		73	71
Payments		0	(106)
Other		(12)	0
Fair value, ending balance	841	902	829
Current liability		289
Contingent consideration	841	902	$ 829
Sanofi Pasteur
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance		711
Fair value, ending balance	711	747
Contingent consideration	$ 711	$ 747
Contingent consideration, measurement input, discount rate		0.115
Measurement Input, Discount Rate | Sanofi Pasteur
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration, measurement input, discount rate		0.08

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Finished goods	$ 1,628	$ 1,610
Raw materials and work in process	6,135	5,949
Supplies	190	146
Total (approximates current cost)	7,953	7,705
Increase (decrease) to LIFO cost	23	(81)
Total current and noncurrent inventories	7,976	7,624
Recognized as:
Inventories	5,603	5,554
Other assets	$ 2,373	$ 2,070

Inventories - Narrative (Detail

Inventories - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Inventory [Line Items]
Inventories classified in Other assets	$ 2,373	$ 2,070
Inventories Not Expected to be Sold Within One Year
Inventory [Line Items]
Inventories classified in Other assets	1,900	1,800
Inventories Produced in Preparation for Product Launches
Inventory [Line Items]
Inventories classified in Other assets	$ 519	$ 279

Goodwill and Intangibles (Detai

Goodwill and Intangibles (Details) - USD ($) $ in Millions	Jun. 02, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 1,400	$ 1,356
Other intangibles, net	519	$ 503
Technology Rights
Finite-Lived Intangible Assets [Line Items]
Other intangibles, net	394
License
Finite-Lived Intangible Assets [Line Items]
Other intangibles, net	$ 125

Contingencies - Narrative (Deta

Contingencies - Narrative (Details) $ in Millions	1 Months Ended	9 Months Ended
	Mar. 31, 2014case	Sep. 30, 2021USD ($)caseclaim	Dec. 31, 2020USD ($)
Legal Defense Costs
Loss Contingencies [Line Items]
Legal defense costs reserve | $		$ 225	$ 235
Zetia antitrust litigation
Loss Contingencies [Line Items]
Loss contingency, pending claims | claim		35
Fosamax
Loss Contingencies [Line Items]
Loss contingency, pending claims		3,470
Fosamax | Femur Fracture Litigation | Federal
Loss Contingencies [Line Items]
Loss contingency, claims on appeal	515
Loss contingency, claims dismissed	650
Januvia
Loss Contingencies [Line Items]
Loss contingency, pending claims | claim		730
Januvia | Other State Court
Loss Contingencies [Line Items]
Loss contingency, pending claims | claim		6
Januvia | Cases Company Agreed To Toll Statute Of Limitations
Loss Contingencies [Line Items]
Loss contingency, pending claims | claim		50
Bridion | Patents
Loss Contingencies [Line Items]
Loss contingency, claims settled		3
Januvia and Janumet | Patents
Loss Contingencies [Line Items]
Loss contingency, claims settled		16

Equity - Rollforward Reconcilia

Equity - Rollforward Reconciliations (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 02, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, beginning balance (in shares)				3,577,103,522
Equity, beginning balance		$ 33,388	$ 27,744	$ 25,404	$ 26,001
Net income (loss) attributable to Merck & Co., Inc.		4,567	2,941	9,291	9,161
Other comprehensive income (loss), net of taxes		38	10	1,595	(190)
Cash dividends declared on common stock		(1,653)	(1,558)	(4,962)	(4,656)
Treasury stock shares purchased		(583)		(822)	(1,281)
Spin-off of Organon & Co.				5,091
Share-based compensation plans and other		131	151	283	245
Net income attributable to noncontrolling interests		4	4	12	12
Distributions attributable to noncontrolling interests		$ (29)	(22)	$ (29)	(22)
Shares, ending balance (in shares)		3,577,103,522		3,577,103,522
Equity, ending balance		$ 35,863	$ 29,270	$ 35,863	$ 29,270
Cash dividends declared on common stock (in dollars per share)		$ 0.65	$ 0.61	$ 1.95	$ 1.83
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, beginning balance (in shares)		3,577,000,000	3,577,000,000	3,577,000,000	3,577,000,000
Equity, beginning balance		$ 1,788	$ 1,788	$ 1,788	$ 1,788
Shares, ending balance (in shares)		3,577,000,000	3,577,000,000	3,577,000,000	3,577,000,000
Equity, ending balance		$ 1,788	$ 1,788	$ 1,788	$ 1,788
Other Paid-In Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity, beginning balance		44,039	39,373	39,588	39,660
Spin-off of Organon & Co.	$ 4,600			4,643
Share-based compensation plans and other		110	116	(82)	(171)
Equity, ending balance		44,149	39,489	44,149	39,489
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity, beginning balance		48,777	49,724	47,362	46,602
Net income (loss) attributable to Merck & Co., Inc.		4,567	2,941	9,291	9,161
Cash dividends declared on common stock		(1,653)	(1,558)	(4,962)	(4,656)
Equity, ending balance		51,691	51,107	51,691	51,107
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity, beginning balance		(4,628)	(6,393)	(6,634)	(6,193)
Other comprehensive income (loss), net of taxes		38	10	1,595	(190)
Spin-off of Organon & Co.	$ 449			449
Equity, ending balance		$ (4,590)	$ (6,383)	$ (4,590)	$ (6,383)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, beginning balance (in shares)		1,044,000,000	1,048,000,000	1,047,000,000	1,038,000,000
Equity, beginning balance		$ (56,682)	$ (56,850)	$ (56,787)	$ (55,950)
Treasury stock shares purchased (in shares)		8,000,000		11,000,000	16,000,000
Treasury stock shares purchased		$ (583)		$ (822)	$ (1,281)
Share-based compensation plans and other (in shares)			(1,000,000)	(6,000,000)	(7,000,000)
Share-based compensation plans and other		$ 21	$ 35	$ 365	$ 416
Shares, ending balance (in shares)		1,052,000,000	1,047,000,000	1,052,000,000	1,047,000,000
Equity, ending balance		$ (57,244)	$ (56,815)	$ (57,244)	$ (56,815)
Non- controlling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity, beginning balance		94	102	87	94
Spin-off of Organon & Co.				(1)
Net income attributable to noncontrolling interests		4	4	12	12
Distributions attributable to noncontrolling interests		(29)	(22)	(29)	(22)
Equity, ending balance		$ 69	$ 84	$ 69	$ 84

Pension and Other Postretirem_3

Pension and Other Postretirement Benefit Plans - Net Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 11	$ 13	$ 37	$ 39
Interest cost	12	14	34	43
Expected return on plan assets	(20)	(19)	(59)	(56)
Amortization of unrecognized prior service credit	(16)	(18)	(48)	(54)
Net loss (gain) amortization	(12)	(5)	(30)	(13)
Termination benefits	0	0	37	0
Curtailments	(1)	0	(29)	(1)
Net periodic benefit cost	(26)	(15)	(58)	(42)
U.S. | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	104	96	302	270
Interest cost	102	107	305	323
Expected return on plan assets	(188)	(193)	(568)	(581)
Amortization of unrecognized prior service credit	(9)	(12)	(29)	(37)
Net loss (gain) amortization	75	75	218	228
Termination benefits	2	1	54	5
Curtailments	(1)	1	15	4
Settlements	139	2	139	11
Net periodic benefit cost	224	77	436	223
International | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	75	76	254	222
Interest cost	33	35	92	102
Expected return on plan assets	(105)	(104)	(313)	(309)
Amortization of unrecognized prior service credit	(3)	(3)	(12)	(9)
Net loss (gain) amortization	32	32	110	94
Termination benefits	0	1	3	2
Curtailments	0	0	(27)	(1)
Settlements	0	0	2	2
Net periodic benefit cost	$ 32	$ 37	$ 109	$ 103

Pension and Other Postretirem_4

Pension and Other Postretirement Benefit Plans - Narrative (Details) - USD ($) $ in Millions	Jun. 02, 2021	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2021
Retirement Benefits [Abstract]
Partial settlement charge			$ 125	$ 125
Decrease (increase) to pension liabilities due to remeasurement	$ 1,700	$ (160)
Net pension liabilities transferred	$ 99

Other (Income) Expense, Net - S

Other (Income) Expense, Net - Schedule of Other (Income) Expense, Net (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Component of Other Income / Expense of Nonoperating [Line Items]
Interest income		$ (7)	$ (9)	$ (27)	$ (48)
Interest expense		196	203	597	624
Exchange losses		46	10	202	89
Income from investments in equity securities, net		(683)	(360)	(1,535)	(964)
Net periodic defined benefit plan cost (credit) other than service cost		40	(88)	(159)	(259)
Other, net		(42)	(68)	(85)	(79)
Other (income) expense, net		(450)	(312)	(1,007)	(637)
Unrealized net (losses) gains		$ 90	$ 43	$ (109)	$ 512
Forecast
Component of Other Income / Expense of Nonoperating [Line Items]
Unrealized net (losses) gains	$ 540

Other (Income) Expense, Net - N

Other (Income) Expense, Net - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Other Income and Expenses [Abstract]
Interest paid	$ 570	$ 605

Taxes on Income (Details)

Taxes on Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Examination [Line Items]
Effective income tax rate	13.20%	14.00%	14.40%	15.10%
Internal Revenue Service (IRS) | Domestic Tax Authority
Income Tax Examination [Line Items]
Tax benefit recognized related to settlement			$ 236
Income taxes paid			190
Internal Revenue Service (IRS) | Domestic Tax Authority | Continuing Operations
Income Tax Examination [Line Items]
Tax benefit recognized related to settlement			207
Income taxes paid			172
Internal Revenue Service (IRS) | Domestic Tax Authority | Discontinued Operations
Income Tax Examination [Line Items]
Tax benefit recognized related to settlement			29
Income taxes paid			$ 18

Earnings Per Share - Calculatio

Earnings Per Share - Calculations of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net Income from Continuing Operations Attributable to Merck & Co., Inc.	$ 4,567	$ 2,324	$ 8,525	$ 7,136
Income from Discontinued Operations, Net of Taxes and Amounts Attributable to Noncontrolling Interests	0	617	766	2,025
Net income attributable to Merck & Co., Inc., basic	4,567	2,941	9,291	9,161
Net income attributable to Merck & Co., Inc., diluted	$ 4,567	$ 2,941	$ 9,291	$ 9,161
Average common shares outstanding (in shares)	2,530	2,529	2,531	2,530
Common shares issuable (in shares)	6	9	8	11
Average common shares outstanding assuming dilution (in shares)	2,536	2,538	2,539	2,541
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders:
Income from Continuing Operations (in dollars per share)	$ 1.81	$ 0.92	$ 3.37	$ 2.82
Income from Discontinued Operations (in dollars per share)	0	0.24	0.30	0.80
Net Income (in dollars per share)	1.81	1.16	3.67	3.62
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders:
Income from Continuing Operations (in dollars per share)	1.80	0.92	3.36	2.81
Income from Discontinued Operations (in dollars per share)	0	0.24	0.30	0.80
Net Income (in dollars per share)	$ 1.80	$ 1.16	$ 3.66	$ 3.61
Antidilutive shares (in shares)	8	5	10	5

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Antidilutive shares (in shares)	8	5	10	5

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	Jun. 02, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Equity, beginning balance		$ 33,388	$ 27,744	$ 25,404	$ 26,001
Other comprehensive income (loss) before reclassification adjustments, pretax		(48)	(143)	1,765	(362)
Tax		12	77	(510)	79
Other comprehensive income (loss) before reclassification adjustments, net of taxes		(36)	(66)	1,255	(283)
Reclassification adjustments, pretax		104	94	428	121
Tax		(30)	(18)	(88)	(28)
Reclassification adjustments, net of taxes		74	76	340	93
Other comprehensive income (loss), net of taxes		38	10	1,595	(190)
Spin-off of Organon & Co.				5,091
Equity, ending balance		35,863	29,270	35,863	29,270
Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Equity, beginning balance		(26)	15	(266)	31
Other comprehensive income (loss) before reclassification adjustments, pretax		72	(195)	193	(126)
Tax		(16)	41	(41)	27
Other comprehensive income (loss) before reclassification adjustments, net of taxes		56	(154)	152	(99)
Reclassification adjustments, pretax		36	22	218	(68)
Tax		(8)	(5)	(46)	14
Reclassification adjustments, net of taxes		28	17	172	(54)
Other comprehensive income (loss), net of taxes		84	(137)	324	(153)
Spin-off of Organon & Co.				0
Equity, ending balance		58	(122)	58	(122)
Investments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Equity, beginning balance		0	0	0	18
Other comprehensive income (loss) before reclassification adjustments, pretax		0	0	0	3
Tax		0	0	0	0
Other comprehensive income (loss) before reclassification adjustments, net of taxes		0	0	0	3
Reclassification adjustments, pretax		0	0	0	(21)
Tax		0	0	0	0
Reclassification adjustments, net of taxes		0	0	0	(21)
Other comprehensive income (loss), net of taxes		0	0	0	(18)
Spin-off of Organon & Co.				0
Equity, ending balance		0	0	0	0
Employee Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Equity, beginning balance		(3,028)	(4,162)	(4,540)	(4,261)
Other comprehensive income (loss) before reclassification adjustments, pretax		(24)	2	1,739	(19)
Tax		16	1	(385)	12
Other comprehensive income (loss) before reclassification adjustments, net of taxes		(8)	3	1,354	(7)
Reclassification adjustments, pretax		68	72	210	210
Tax		(22)	(13)	(42)	(42)
Reclassification adjustments, net of taxes		46	59	168	168
Other comprehensive income (loss), net of taxes		38	62	1,522	161
Spin-off of Organon & Co.	$ 28			28
Equity, ending balance		(2,990)	(4,100)	(2,990)	(4,100)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Equity, beginning balance		(1,574)	(2,246)	(1,828)	(1,981)
Other comprehensive income (loss) before reclassification adjustments, pretax		(96)	50	(167)	(220)
Tax		12	35	(84)	40
Other comprehensive income (loss) before reclassification adjustments, net of taxes		(84)	85	(251)	(180)
Reclassification adjustments, pretax		0	0	0	0
Tax		0	0	0	0
Reclassification adjustments, net of taxes		0	0	0	0
Other comprehensive income (loss), net of taxes		(84)	85	(251)	(180)
Spin-off of Organon & Co.	421			421
Equity, ending balance		(1,658)	(2,161)	(1,658)	(2,161)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Equity, beginning balance		(4,628)	(6,393)	(6,634)	(6,193)
Spin-off of Organon & Co.	$ 449			449
Equity, ending balance		$ (4,590)	$ (6,383)	$ (4,590)	$ (6,383)

Segment Reporting - Narrative (

Segment Reporting - Narrative (Details) $ in Billions	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)segment	Sep. 30, 2020USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment			2
Sales discounts | $	$ 3.1	$ 2.9	$ 9.1	$ 8.3

Segment Reporting - Sales from

Segment Reporting - Sales from Products (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Sales	$ 13,154	$ 10,929	$ 35,183	$ 30,570
Revenue related to the sale of the marketing rights	135		185
Operating Segments
Segment Reporting Information [Line Items]
Sales	12,913	10,934	35,021	30,355
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Sales	241	(5)	162	215
United States
Segment Reporting Information [Line Items]
Sales	6,276	5,250	16,166	14,301
United States | Operating Segments
Segment Reporting Information [Line Items]
Sales	6,137	5,241	15,974	14,255
United States | Corporate, Non-Segment
Segment Reporting Information [Line Items]
Sales	139	9	192	46
Int’l
Segment Reporting Information [Line Items]
Sales	6,878	5,679	19,017	16,269
Int’l | Operating Segments
Segment Reporting Information [Line Items]
Sales	6,777	5,693	19,047	16,101
Int’l | Corporate, Non-Segment
Segment Reporting Information [Line Items]
Sales	101	(14)	(30)	168
Pharmaceutical | Operating Segments
Segment Reporting Information [Line Items]
Sales	11,496	9,714	30,714	26,797
Pharmaceutical | Operating Segments | Keytruda
Segment Reporting Information [Line Items]
Sales	4,534	3,715	12,609	10,387
Pharmaceutical | Operating Segments | Alliance revenue - Lynparza
Segment Reporting Information [Line Items]
Sales	246	196	721	519
Pharmaceutical | Operating Segments | Alliance revenue - Lenvima
Segment Reporting Information [Line Items]
Sales	188	142	498	421
Pharmaceutical | Operating Segments | Gardasil/Gardasil 9
Segment Reporting Information [Line Items]
Sales	1,993	1,187	4,144	2,941
Pharmaceutical | Operating Segments | ProQuad/M-M-R II/Varivax
Segment Reporting Information [Line Items]
Sales	661	576	1,626	1,390
Pharmaceutical | Operating Segments | Pneumovax 23
Segment Reporting Information [Line Items]
Sales	277	375	600	748
Pharmaceutical | Operating Segments | RotaTeq
Segment Reporting Information [Line Items]
Sales	227	210	593	601
Pharmaceutical | Operating Segments | Vaqta
Segment Reporting Information [Line Items]
Sales	48	51	138	139
Pharmaceutical | Operating Segments | Bridion
Segment Reporting Information [Line Items]
Sales	369	320	1,096	843
Pharmaceutical | Operating Segments | Prevymis
Segment Reporting Information [Line Items]
Sales	96	77	270	200
Pharmaceutical | Operating Segments | Noxafil
Segment Reporting Information [Line Items]
Sales	64	79	197	247
Pharmaceutical | Operating Segments | Primaxin
Segment Reporting Information [Line Items]
Sales	70	74	194	189
Pharmaceutical | Operating Segments | Cancidas
Segment Reporting Information [Line Items]
Sales	56	50	168	148
Pharmaceutical | Operating Segments | Invanz
Segment Reporting Information [Line Items]
Sales	53	51	157	159
Pharmaceutical | Operating Segments | Zerbaxa
Segment Reporting Information [Line Items]
Sales	(2)	43	(11)	112
Pharmaceutical | Operating Segments | Simponi
Segment Reporting Information [Line Items]
Sales	203	209	619	615
Pharmaceutical | Operating Segments | Remicade
Segment Reporting Information [Line Items]
Sales	73	82	233	242
Pharmaceutical | Operating Segments | Belsomra
Segment Reporting Information [Line Items]
Sales	81	81	238	244
Pharmaceutical | Operating Segments | Isentress/Isentress HD
Segment Reporting Information [Line Items]
Sales	189	205	590	646
Pharmaceutical | Operating Segments | Alliance revenue-Adempas/Verquvo
Segment Reporting Information [Line Items]
Sales	100	83	248	216
Pharmaceutical | Operating Segments | Adempas
Segment Reporting Information [Line Items]
Sales	59	55	188	167
Pharmaceutical | Operating Segments | Januvia
Segment Reporting Information [Line Items]
Sales	852	821	2,445	2,449
Pharmaceutical | Operating Segments | Janumet
Segment Reporting Information [Line Items]
Sales	487	506	1,449	1,499
Pharmaceutical | Operating Segments | Other pharmaceutical
Segment Reporting Information [Line Items]
Sales	572	526	1,704	1,675
Pharmaceutical | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales	5,670	4,842	14,611	13,108
Pharmaceutical | United States | Operating Segments | Keytruda
Segment Reporting Information [Line Items]
Sales	2,580	2,157	7,108	6,106
Pharmaceutical | United States | Operating Segments | Alliance revenue - Lynparza
Segment Reporting Information [Line Items]
Sales	129	107	371	297
Pharmaceutical | United States | Operating Segments | Alliance revenue - Lenvima
Segment Reporting Information [Line Items]
Sales	114	82	287	270
Pharmaceutical | United States | Operating Segments | Gardasil/Gardasil 9
Segment Reporting Information [Line Items]
Sales	839	579	1,605	1,209
Pharmaceutical | United States | Operating Segments | ProQuad/M-M-R II/Varivax
Segment Reporting Information [Line Items]
Sales	537	437	1,255	1,033
Pharmaceutical | United States | Operating Segments | Pneumovax 23
Segment Reporting Information [Line Items]
Sales	181	276	354	478
Pharmaceutical | United States | Operating Segments | RotaTeq
Segment Reporting Information [Line Items]
Sales	135	114	364	355
Pharmaceutical | United States | Operating Segments | Vaqta
Segment Reporting Information [Line Items]
Sales	32	32	80	79
Pharmaceutical | United States | Operating Segments | Bridion
Segment Reporting Information [Line Items]
Sales	181	162	545	412
Pharmaceutical | United States | Operating Segments | Prevymis
Segment Reporting Information [Line Items]
Sales	39	32	111	87
Pharmaceutical | United States | Operating Segments | Noxafil
Segment Reporting Information [Line Items]
Sales	19	13	48	27
Pharmaceutical | United States | Operating Segments | Primaxin
Segment Reporting Information [Line Items]
Sales	0	1	0	2
Pharmaceutical | United States | Operating Segments | Cancidas
Segment Reporting Information [Line Items]
Sales	1	1	4	2
Pharmaceutical | United States | Operating Segments | Invanz
Segment Reporting Information [Line Items]
Sales	(2)	1	(2)	7
Pharmaceutical | United States | Operating Segments | Zerbaxa
Segment Reporting Information [Line Items]
Sales	(1)	20	(5)	57
Pharmaceutical | United States | Operating Segments | Simponi
Segment Reporting Information [Line Items]
Sales	0	0	0	0
Pharmaceutical | United States | Operating Segments | Remicade
Segment Reporting Information [Line Items]
Sales	0	0	0	0
Pharmaceutical | United States | Operating Segments | Belsomra
Segment Reporting Information [Line Items]
Sales	23	18	56	67
Pharmaceutical | United States | Operating Segments | Isentress/Isentress HD
Segment Reporting Information [Line Items]
Sales	77	92	222	243
Pharmaceutical | United States | Operating Segments | Alliance revenue-Adempas/Verquvo
Segment Reporting Information [Line Items]
Sales	73	78	222	200
Pharmaceutical | United States | Operating Segments | Adempas
Segment Reporting Information [Line Items]
Sales	0	0	0	0
Pharmaceutical | United States | Operating Segments | Januvia
Segment Reporting Information [Line Items]
Sales	365	342	997	1,110
Pharmaceutical | United States | Operating Segments | Janumet
Segment Reporting Information [Line Items]
Sales	86	105	244	361
Pharmaceutical | United States | Operating Segments | Other pharmaceutical
Segment Reporting Information [Line Items]
Sales	262	193	745	706
Pharmaceutical | Int’l | Operating Segments
Segment Reporting Information [Line Items]
Sales	5,826	4,872	16,103	13,690
Pharmaceutical | Int’l | Operating Segments | Keytruda
Segment Reporting Information [Line Items]
Sales	1,954	1,559	5,501	4,281
Pharmaceutical | Int’l | Operating Segments | Alliance revenue - Lynparza
Segment Reporting Information [Line Items]
Sales	117	89	350	223
Pharmaceutical | Int’l | Operating Segments | Alliance revenue - Lenvima
Segment Reporting Information [Line Items]
Sales	74	60	211	152
Pharmaceutical | Int’l | Operating Segments | Gardasil/Gardasil 9
Segment Reporting Information [Line Items]
Sales	1,154	608	2,539	1,732
Pharmaceutical | Int’l | Operating Segments | ProQuad/M-M-R II/Varivax
Segment Reporting Information [Line Items]
Sales	125	139	371	356
Pharmaceutical | Int’l | Operating Segments | Pneumovax 23
Segment Reporting Information [Line Items]
Sales	97	99	247	270
Pharmaceutical | Int’l | Operating Segments | RotaTeq
Segment Reporting Information [Line Items]
Sales	92	96	229	246
Pharmaceutical | Int’l | Operating Segments | Vaqta
Segment Reporting Information [Line Items]
Sales	16	19	58	60
Pharmaceutical | Int’l | Operating Segments | Bridion
Segment Reporting Information [Line Items]
Sales	188	157	551	431
Pharmaceutical | Int’l | Operating Segments | Prevymis
Segment Reporting Information [Line Items]
Sales	57	46	159	113
Pharmaceutical | Int’l | Operating Segments | Noxafil
Segment Reporting Information [Line Items]
Sales	45	66	149	220
Pharmaceutical | Int’l | Operating Segments | Primaxin
Segment Reporting Information [Line Items]
Sales	69	73	194	187
Pharmaceutical | Int’l | Operating Segments | Cancidas
Segment Reporting Information [Line Items]
Sales	56	49	164	147
Pharmaceutical | Int’l | Operating Segments | Invanz
Segment Reporting Information [Line Items]
Sales	55	50	159	152
Pharmaceutical | Int’l | Operating Segments | Zerbaxa
Segment Reporting Information [Line Items]
Sales	(1)	23	(6)	54
Pharmaceutical | Int’l | Operating Segments | Simponi
Segment Reporting Information [Line Items]
Sales	203	209	619	615
Pharmaceutical | Int’l | Operating Segments | Remicade
Segment Reporting Information [Line Items]
Sales	73	82	233	242
Pharmaceutical | Int’l | Operating Segments | Belsomra
Segment Reporting Information [Line Items]
Sales	58	63	183	177
Pharmaceutical | Int’l | Operating Segments | Isentress/Isentress HD
Segment Reporting Information [Line Items]
Sales	112	113	368	403
Pharmaceutical | Int’l | Operating Segments | Alliance revenue-Adempas/Verquvo
Segment Reporting Information [Line Items]
Sales	27	5	26	16
Pharmaceutical | Int’l | Operating Segments | Adempas
Segment Reporting Information [Line Items]
Sales	59	55	188	167
Pharmaceutical | Int’l | Operating Segments | Januvia
Segment Reporting Information [Line Items]
Sales	487	479	1,448	1,339
Pharmaceutical | Int’l | Operating Segments | Janumet
Segment Reporting Information [Line Items]
Sales	401	400	1,205	1,138
Pharmaceutical | Int’l | Operating Segments | Other pharmaceutical
Segment Reporting Information [Line Items]
Sales	308	333	957	969
Animal Health | Operating Segments
Segment Reporting Information [Line Items]
Sales	1,417	1,220	4,307	3,535
Animal Health | Operating Segments | Livestock
Segment Reporting Information [Line Items]
Sales	864	758	2,503	2,145
Animal Health | Operating Segments | Companion Animals
Segment Reporting Information [Line Items]
Sales	553	462	1,804	1,390
Animal Health | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales	467	399	1,363	1,124
Animal Health | United States | Operating Segments | Livestock
Segment Reporting Information [Line Items]
Sales	190	165	508	448
Animal Health | United States | Operating Segments | Companion Animals
Segment Reporting Information [Line Items]
Sales	277	234	855	676
Animal Health | Int’l | Operating Segments
Segment Reporting Information [Line Items]
Sales	951	821	2,944	2,411
Animal Health | Int’l | Operating Segments | Livestock
Segment Reporting Information [Line Items]
Sales	675	593	1,996	1,697
Animal Health | Int’l | Operating Segments | Companion Animals
Segment Reporting Information [Line Items]
Sales	276	228	948	714
Other Segments | Operating Segments
Segment Reporting Information [Line Items]
Sales	0	0	0	23
Other Segments | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales	0	0	0	23
Other Segments | Int’l | Operating Segments
Segment Reporting Information [Line Items]
Sales	$ 0	$ 0	$ 0	$ 0

Segment Reporting - Consolidate

Segment Reporting - Consolidated Sales by Geographic Area (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue from External Customer [Line Items]
Sales	$ 13,154	$ 10,929	$ 35,183	$ 30,570
United States
Revenue from External Customer [Line Items]
Sales	6,276	5,250	16,166	14,301
Europe, Middle East and Africa
Revenue from External Customer [Line Items]
Sales	3,342	2,946	9,912	8,537
China
Revenue from External Customer [Line Items]
Sales	1,307	791	3,004	2,060
Japan
Revenue from External Customer [Line Items]
Sales	638	671	1,929	1,875
Asia Pacific (other than China and Japan)
Revenue from External Customer [Line Items]
Sales	613	545	1,782	1,560
Latin America
Revenue from External Customer [Line Items]
Sales	599	499	1,631	1,374
Other
Revenue from External Customer [Line Items]
Sales	$ 379	$ 227	$ 759	$ 863

Segment Reporting - Reconciliat

Segment Reporting - Reconciliation of Segment Profits to Income before Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Profits	$ 5,266	$ 2,706	$ 9,970	$ 8,408
Interest income	7	9	27	48
Interest expense	(196)	(203)	(597)	(624)
Amortization			(1,231)	(1,393)
Depreciation			(1,148)	(1,210)
Research and development	(2,445)	(3,349)	(9,177)	(7,609)
Restructuring costs	(107)	(113)	(487)	(265)
Operating Segments
Segment Reporting Information [Line Items]
Profits	9,111	7,484	24,079	20,583
Operating Segments | Pharmaceutical segment
Segment Reporting Information [Line Items]
Profits	8,606	7,026	22,450	19,235
Operating Segments | Animal Health segment
Segment Reporting Information [Line Items]
Profits	505	459	1,629	1,347
Operating Segments | Other segment
Segment Reporting Information [Line Items]
Profits	0	(1)	0	1
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Profits	141	(28)	29	135
Segment Reconciling Items
Segment Reporting Information [Line Items]
Interest income	7	9	27	48
Interest expense	(196)	(203)	(597)	(624)
Amortization	(360)	(406)	(1,231)	(1,393)
Depreciation	(358)	(367)	(1,031)	(1,105)
Research and development	(2,312)	(3,231)	(8,775)	(7,251)
Restructuring costs	(107)	(113)	(487)	(265)
Other unallocated, net	$ (660)	$ (439)	$ (2,044)	$ (1,720)