Merck & Co. (MRK) 10-Q 7 Aug 23 2023 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2023	Jul. 31, 2023
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2023
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	126 East Lincoln Avenue
Entity Address, City or Town	Rahway
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	07065
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		2,537,521,169
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
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 OPERATIONS - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
Sales	$ 15,035	$ 14,593	$ 29,522	$ 30,494
Costs, Expenses and Other
Cost of sales	4,024	4,216	7,951	9,596
Selling, general and administrative	2,702	2,512	5,182	4,834
Research and development	13,321	2,798	17,597	5,374
Restructuring costs	151	142	218	194
Other (income) expense, net	172	438	259	1,148
Total Costs, Expenses and Other	20,370	10,106	31,207	21,146
(Loss) Income Before Taxes	(5,335)	4,487	(1,685)	9,348
Income Tax Provision	637	538	1,462	1,092
Net (Loss) Income	(5,972)	3,949	(3,147)	8,256
Less: Net Income Attributable to Noncontrolling Interests	3	5	7	2
Net (Loss) Income Attributable to Merck & Co., Inc.	$ (5,975)	$ 3,944	$ (3,154)	$ 8,254
Basic (Loss) Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share)	$ (2.35)	$ 1.56	$ (1.24)	$ 3.26
(Loss) Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share)	$ (2.35)	$ 1.55	$ (1.24)	$ 3.25

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net (Loss) Income Attributable to Merck & Co., Inc.	$ (5,975)	$ 3,944	$ (3,154)	$ 8,254
Other Comprehensive (Loss) Income Net of Taxes:
Net unrealized gain on derivatives, net of reclassifications	145	183	12	246
Benefit plan net (loss) gain and prior service (cost) credit, net of amortization	(25)	246	(75)	278
Cumulative translation adjustment	(137)	(387)	(69)	(422)
Other comprehensive income (loss), net of taxes	(17)	42	(132)	102
Comprehensive (Loss) Income Attributable to Merck & Co., Inc.	$ (5,992)	$ 3,986	$ (3,286)	$ 8,356

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEET - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Current Assets
Cash and cash equivalents	$ 5,660	$ 12,694
Short-term investments	718	498
Accounts receivable (net of allowance for doubtful accounts of $86 in 2023 and $72 in 2022)	11,030	9,450
Inventories (excludes inventories of $3,220 in 2023 and $2,938 in 2022 classified in Other assets - see Note 7)	5,930	5,911
Other current assets	6,639	7,169
Total current assets	29,977	35,722
Investments	1,214	1,015
Property, Plant and Equipment, at cost, net of accumulated depreciation of $18,432 in 2023 and $17,985 in 2022	22,231	21,422
Goodwill	21,195	21,204
Other Intangibles, Net	19,665	20,269
Other Assets	10,187	9,528
Total Assets	104,469	109,160
Current Liabilities
Loans payable and current portion of long-term debt	2,839	1,946
Trade accounts payable	3,442	4,264
Accrued and other current liabilities	13,747	14,159
Income taxes payable	1,489	1,986
Dividends payable	1,877	1,884
Total current liabilities	23,394	24,239
Long-Term Debt	34,072	28,745
Deferred Income Taxes	996	1,795
Other Noncurrent Liabilities	7,265	8,323
Merck & Co., Inc. Stockholders’ Equity
Common stock, $0.50 par value Authorized - 6,500,000,000 shares Issued - 3,577,103,522 shares in 2023 and 2022	1,788	1,788
Other paid-in capital	44,219	44,379
Retained earnings	54,198	61,081
Accumulated other comprehensive loss	(4,900)	(4,768)
Stockholders' equity before deduction for treasury stock	95,305	102,480
Less treasury stock, at cost: 1,037,678,033 shares in 2023 and 1,039,269,638 shares in 2022	56,612	56,489
Total Merck & Co., Inc. stockholders’ equity	38,693	45,991
Noncontrolling Interests	49	67
Total equity	38,742	46,058
Liabilities and Equity	$ 104,469	$ 109,160

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEET (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 86	$ 72
Inventories classified in Other assets	3,220	2,938
Accumulated depreciation	$ 18,432	$ 17,985
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)	1,037,678,033	1,039,269,638

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash Flows from Operating Activities
Net (loss) income	$ (3,147)	$ 8,256
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Amortization	1,020	1,163
Depreciation	874	895
(Income) loss from investments in equity securities, net	(274)	991
Charge for the acquisition of Prometheus Biosciences, Inc.	10,217	0
Charge for the acquisition of Imago BioSciences, Inc.	1,192	0
Deferred income taxes	(632)	(600)
Share-based compensation	314	257
Other	5	799
Net changes in assets and liabilities	(4,526)	(2,698)
Net Cash Provided by Operating Activities	5,043	9,063
Cash Flows from Investing Activities
Capital expenditures	(1,972)	(2,113)
Purchases of securities and other investments	(587)	(705)
Proceeds from sales of securities and other investments	785	374
Acquisition of Prometheus Biosciences, Inc., net of cash acquired	(10,705)	0
Acquisition of Imago BioSciences, Inc., net of cash acquired	(1,327)	0
Other	4	194
Net Cash Used in Investing Activities	(13,802)	(2,250)
Cash Flows from Financing Activities
Net change in short-term borrowings	1,937	0
Proceeds from issuance of debt	5,946	0
Payments on debt	(1,751)	(1,250)
Purchases of treasury stock	(487)	0
Dividends paid to stockholders	(3,738)	(3,515)
Proceeds from exercise of stock options	112	109
Other	(315)	(207)
Net Cash Provided by (Used in) Financing Activities	1,704	(4,863)
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	(6)	(364)
Net (Decrease) Increase in Cash, Cash Equivalents and Restricted Cash	(7,061)	1,586
Cash, Cash Equivalents and Restricted Cash at Beginning of Year (includes restricted cash of $79 and $71 at January 1, 2023 and 2022, respectively, included in Other current assets)	12,773	8,167
Cash, Cash Equivalents and Restricted Cash at End of Period (includes restricted cash of $52 and $78 at June 30, 2023 and 2022, respectively, included in Other current assets)	$ 5,712	$ 9,753

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Statement of Cash Flows [Abstract]
Restricted cash	$ 52	$ 79	$ 78	$ 71

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2023
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 24, 2023. 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. Certain reclassifications have been made to prior year amounts to conform to the current year presentation. Recently Adopted Accounting Standards In October 2021, the FASB issued amended guidance that requires acquiring entities to recognize and measure contract assets and liabilities in a business combination in accordance with existing revenue recognition guidance. The Company adopted the guidance effective January 1, 2023. The adoption of this guidance did not have an impact on the Company’s consolidated financial statements for prior acquisitions; however, the impact in future periods will be dependent upon the contract assets and contract liabilities acquired in future business combinations. In June 2022, the FASB issued guidance related to the fair value measurement of an equity security subject to contractual restrictions that prohibit the sale of the equity security. The new guidance also introduces new disclosure requirements for equity securities subject to contractual sale restrictions that are measured at fair value. The Company adopted the guidance effective July 1, 2023. There was no impact to the Company’s consolidated financial statements upon adoption.

Acquisitions, Research Collabor

Acquisitions, Research Collaborations and License Agreements	6 Months Ended
	Jun. 30, 2023
Business Combination and Asset Acquisition [Abstract]
Acquisitions, Research Collaborations and License Agreements	Acquisitions, Research Collaborations and Licensing 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 June 2023, Merck acquired Prometheus Biosciences, Inc. (Prometheus), a clinical-stage biotechnology company pioneering a precision medicine approach for the discovery, development, and commercialization of novel therapeutic and companion diagnostic products for the treatment of immune-mediated diseases. Total consideration paid of $11.0 billion included $1.2 billion of costs to settle share-based equity awards (including $700 million to settle unvested equity awards). Prometheus’ lead candidate, MK-7240 (formerly PRA023), is a humanized monoclonal antibody directed to tumor necrosis factor-like ligand 1A, a target associated with both intestinal inflammation and fibrosis. MK-7240 is being developed for the treatment of immune-mediated diseases including ulcerative colitis, Crohn’s disease, and other autoimmune conditions. The transaction was accounted for as an acquisition of an asset since MK-7240 accounted for substantially all of the fair value of the gross assets acquired (excluding cash and deferred income taxes). Merck recorded net assets of $877 million, including cash of $368 million, investments of $296 million, deferred tax assets of $218 million and other net liabilities of $5 million, as well as Research and development expenses of $10.2 billion in the second quarter and first six months of 2023 related to the transaction. There are no future contingent payments associated with the acquisition. In February 2023, Merck and Kelun-Biotech (a holding subsidiary of Sichuan Kelun Pharmaceutical Co., Ltd.) closed a license and collaboration agreement expanding their relationship in which Merck gained exclusive rights for the research, development, manufacture and commercialization of up to seven investigational preclinical antibody drug conjugates (ADCs) for the treatment of cancer. Kelun-Biotech retained the right to research, develop, manufacture and commercialize certain licensed and option ADCs for Chinese mainland, Hong Kong and Macau. Merck made an upfront payment of $175 million, which was recorded in Research and development expenses in the first six months of 2023. In addition, Kelun-Biotech is eligible to receive future contingent development-related payments aggregating up to $1.0 billion, $2.8 billion in regulatory milestones, and $5.5 billion in sales-based milestones if Kelun-Biotech does not retain Chinese mainland, Hong Kong and Macau rights for the option ADCs and all candidates achieve regulatory approval. In addition, Kelun-Biotech is eligible to receive tiered royalties ranging from a mid-single-digit rate to a low-double-digit rate on future net sales for any commercialized ADC product. Also, in connection with the agreement, Merck invested $100 million in Kelun-Biotech’s Series B preferred shares in January 2023. In January 2023, Merck acquired Imago BioSciences, Inc. (Imago), a clinical stage biopharmaceutical company developing new medicines for the treatment of myeloproliferative neoplasms and other bone marrow diseases, for $1.35 billion (including payments to settle share-based equity awards) and also incurred approximately $60 million of transaction costs. Imago’s lead candidate bomedemstat, MK-3543 (formerly IMG-7289), is an investigational orally available lysine-specific demethylase 1 inhibitor currently being evaluated in multiple Phase 2 clinical trials for the treatment of essential thrombocythemia, myelofibrosis, and polycythemia vera, in addition to other indications. The transaction was accounted for as an acquisition of an asset since bomedemstat represented substantially all of the fair value of the gross assets acquired (excluding cash and deferred income taxes). Merck recorded net assets of $219 million, as well as Research and development expenses of $1.2 billion in the first six months of 2023 related to the transaction. There are no future contingent payments associated with the acquisition. In May 2022, in connection with an existing arrangement, Merck exercised its option to obtain an exclusive license outside of Chinese mainland, Hong Kong, Macau and Taiwan for the development, manufacture and commercialization of Kelun-Biotech’s trophoblast antigen 2 (TROP2)-targeting ADC programs, including its lead compound, SKB-264 (MK-2870), which is currently in Phase 2 clinical development. Under the terms of the agreement, Merck and Kelun-Biotech will collaborate on certain early clinical development plans, including evaluating the potential of MK-2870 as a monotherapy and in combination with Keytruda for advanced solid tumors. Upon option exercise, Merck made a payment of $30 million, which was recorded in Research and development expenses in the second quarter and first six months of 2022, and agreed to make additional payments of $30 million upon completion of specified project activities and $25 million upon technology transfer. Merck also agreed to make quarterly payments in 2022 and 2023 aggregating up to $111 million to fund Kelun-Biotech’s ongoing research and development activities, of which $81 million has been paid through June 2023. In addition, Kelun-Biotech is eligible to receive future contingent milestone payments (which include all program compounds) aggregating up to $90 million in developmental milestones, $290 million in first commercial sale milestones, and $780 million in sales-based milestones. The agreement also provides for Merck to pay tiered royalties ranging from a mid-single-digit rate to a low-double-digit rate on future net sales.

Collaborative Arrangements

Collaborative Arrangements	6 Months Ended
	Jun. 30, 2023
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. AstraZeneca PLC 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 (pembrolizumab) 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 contingent payments from Merck to AstraZeneca related to the successful achievement of sales-based and regulatory milestones. In the first quarter of 2022, Merck determined it was probable that sales of Lynparza in the future would trigger a $600 million sales-based milestone payment from Merck to AstraZeneca. Accordingly, Merck recorded a $600 million liability (which remained accrued at June 30, 2023) and a corresponding increase to the intangible asset related to Lynparza. Merck also recognized $250 million of cumulative amortization catch-up expense related to the recognition of this milestone in the first six months of 2022. Additionally, in the first six months of 2022, Merck made a sales-based milestone payment to AstraZeneca (which had been previously accrued for) of $400 million. Potential future sales-based milestone payments of $2.1 billion have not yet been accrued as they are not deemed by the Company to be probable at this time. In the first quarter of 2023, Merck made a regulatory milestone payment to AstraZeneca of $105 million (which had been previously accrued for). In the second quarter of 2023, Lynparza received a regulatory approval triggering a future milestone payment of up to $245 million from Merck to AstraZeneca. In 2022, Lynparza received regulatory approvals triggering capitalized milestone payments of $250 million from Merck to AstraZeneca (of which $175 million was paid in the first six months of 2022). Potential future regulatory milestone payments of $850 million remain under the agreement. The intangible asset balance related to Lynparza (which includes capitalized sales-based and regulatory milestone payments) was $1.7 billion at June 30, 2023 and is included in Other Intangibles, Net . The amount is being amortized over its estimated useful life through 2028 as supported by projected future cash flows, subject to impairment testing. Summarized financial information related to this collaboration is as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Alliance revenue - Lynparza $ 310 $ 275 $ 585 $ 541 Alliance revenue - Koselugo 25 24 48 33 Total alliance revenue $ 335 $ 299 $ 633 $ 574 Cost of sales (1) 78 62 148 361 Selling, general and administrative 51 46 98 90 Research and development 22 25 43 51 ($ in millions) June 30, 2023 December 31, 2022 Receivables from AstraZeneca included in Other current assets $ 332 $ 303 Payables to AstraZeneca included in Accrued and other current liabilities (2) 260 123 Payables to AstraZeneca included in Other Noncurrent Liabilities (2) 600 600 (1) Represents amortization of capitalized milestone payments. Amount in the first six months of 2022 includes $250 million of cumulative amortization catch-up expense as noted above. (2) Includes accrued milestone payments. Eisai Co., Ltd. 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 option rights. In addition, the agreement provides for contingent payments from Merck to Eisai related to the successful achievement of sales-based and regulatory milestones. In the first quarter of 2023, Merck determined it was probable that sales of Lenvima in the future would trigger a $125 million sales-based milestone payment from Merck to Eisai. Accordingly, Merck recorded a $125 million liability and a corresponding increase to the intangible asset related to Lenvima. Merck also recognized $72 million of cumulative amortization catch-up expense related to the recognition of this milestone in the first six months of 2023. The Company made this sales-based milestone payment to Eisai in the second quarter of 2023. In the first six months of 2022, Merck made sales-based milestone payments to Eisai (which had been previously accrued for) aggregating $600 million. Potential future sales-based milestone payments of $2.4 billion have not yet been accrued as they are not deemed by the Company to be probable at this time. In 2022, Lenvima received regulatory approvals triggering capitalized milestone payments of $50 million from Merck to Eisai (of which $25 million was paid in the first six months of 2022). There are no regulatory milestone payments remaining under the agreement. The intangible asset balance related to Lenvima (which includes capitalized sales-based and regulatory milestone payments) was $756 million at June 30, 2023 and is included in Other Intangibles, Net . The amount is being amortized over its estimated useful life through 2026 as supported by projected future cash flows, subject to impairment testing. Summarized financial information related to this collaboration is as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Alliance revenue - Lenvima $ 242 $ 231 $ 474 $ 459 Cost of sales (1) 57 53 183 106 Selling, general and administrative 48 42 99 73 Research and development 17 47 56 104 ($ in millions) June 30, 2023 December 31, 2022 Receivables from Eisai included in Other current assets $ 242 $ 214 (1) Represents amortization of capitalized milestone payments. Amount in the first six months of 2023 includes $72 million of cumulative amortization catch-up expense as noted above. 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., the European Union (EU) and Japan in 2021, and has since been approved in several other markets. 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 of Adempas and Verquvo 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 provided for contingent payments from Merck to Bayer related to the successful achievement of sales-based milestones. In the first six months of 2022, Merck made the final $400 million sales-based milestone payment under this collaboration to Bayer. The intangible asset balances related to Adempas (which includes the acquired intangible asset balance, as well as capitalized sales-based milestone payments attributed to Adempas) and Verquvo (which reflects the portion of the final sales-based milestone payment that was attributed to Verquvo) were $586 million and $55 million, respectively, at June 30, 2023 and are included in Other Intangibles, Net . The assets are being amortized over their estimated useful lives (through 2027 for Adempas and through 2031 for Verquvo) as supported by projected future cash flows, subject to impairment testing. Summarized financial information related to this collaboration is as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Alliance revenue - Adempas/Verquvo $ 68 $ 98 $ 167 $ 170 Net sales of Adempas recorded by Merck 65 63 125 124 Net sales of Verquvo recorded by Merck 9 6 16 9 Total sales $ 142 $ 167 $ 308 $ 303 Cost of sales (1) 56 54 113 103 Selling, general and administrative 34 42 67 65 Research and development 25 17 50 34 ($ in millions) June 30, 2023 December 31, 2022 Receivables from Bayer included in Other current assets $ 144 $ 143 Payables to Bayer included in Accrued and other current liabilities 82 80 (1) Includes amortization of intangible assets. Ridgeback Biotherapeutics LP In 2020, Merck and Ridgeback Biotherapeutics LP (Ridgeback), a closely held biotechnology company, entered into a collaboration agreement to develop Lagevrio (molnupiravir), an investigational orally available antiviral candidate for the treatment of patients with COVID-19. Merck gained exclusive worldwide rights to develop and commercialize Lagevrio and related molecules. Following initial authorizations in certain markets in the fourth quarter of 2021, Lagevrio has since received multiple additional authorizations worldwide. Under the terms of the agreement, Ridgeback received an upfront payment and is eligible to receive future contingent payments dependent upon the achievement of certain developmental and regulatory approval milestones. The agreement also provides for Merck to reimburse Ridgeback for a portion of certain third-party contingent milestone payments and royalties on net sales, which is part of the profit-sharing calculation. Merck is the principal on sales transactions, recognizing sales and related costs, with profit-sharing amounts recorded within Cost of sales . Profits from the collaboration are split equally between the partners. Reimbursements from Ridgeback for its share of research and development costs (deducted from Ridgeback’s share of profits) are reflected as decreases to Research and development expenses. Summarized financial information related to this collaboration is as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Net sales of Lagevrio recorded by Merck $ 203 $ 1,177 $ 595 $ 4,424 Cost of sales (1)(2) 193 615 414 2,341 Selling, general and administrative (2) 24 34 51 69 Research and development (2) 10 30 26 56 ($ in millions) June 30, 2023 December 31, 2022 Receivables from Ridgeback included in Other current assets (3) $ 51 $ — Payables to Ridgeback included in Accrued and other current liabilities (4) 30 348 (1) Includes royalty expense, amortization of capitalized milestone payments and inventory reserves. (2) Expenses include an allocation for overhead charges. (3) Includes partner advances. (4) Includes accrued royalties. Amount at December 31, 2022 also includes an accrued milestone payment . Bristol-Myers Squibb Company Reblozyl (luspatercept-aamt) is a first-in-class erythroid maturation recombinant fusion protein that is being commercialized through a global collaboration with Bristol-Myers Squibb Company (BMS). Reblozyl is approved in the U.S., Europe and certain other markets for the treatment of anemia in certain rare blood disorders and is also being evaluated for additional indications for hematology therapies. BMS is the principal on sales transactions for Reblozyl; however, Merck co-promotes Reblozyl (and will co-promote all future products approved under this collaboration) in North America, which is reimbursed by BMS. Merck receives a 20% sales royalty from BMS which could increase to a maximum of 24% based on sales levels. This royalty will be reduced by 50% upon the earlier of patent expiry or generic entry on an indication-by-indication basis in each market. Additionally, Merck is eligible to receive future contingent sales-based milestone payments of up to $80 million. Alliance revenue related to this collaboration (recorded within Sales ) consists of royalties and, for the first six months of 2022, also includes the receipt of a regulatory approval milestone payment of $20 million. Merck recorded alliance revenue related to this collaboration of $47 million and $90 million in the second quarter and first six months of 2023, respectively, compared with $33 million and $86 million in the second quarter and first six months of 2022, respectively.

Spin-Off of Organon & Co.

Spin-Off of Organon & Co.	6 Months Ended
	Jun. 30, 2023
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, 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 is providing Organon various services and, similarly, Organon is providing Merck various services. A majority of the services provided under the TSA terminated within 25 months following the spin-off; a majority of the remaining services will terminate within 35 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 is continuing 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 is continuing 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 is (a) manufacturing and supplying certain active pharmaceutical ingredients for Organon, (b) manufacturing and supplying certain formulated pharmaceutical products for Organon, and (c) packaging and labeling certain finished pharmaceutical products for Organon. Similarly, Organon and Merck entered into a number of MSAs pursuant to which Organon is (a) manufacturing and supplying certain formulated pharmaceutical products for Merck, and (b) packaging and labeling certain finished pharmaceutical products for Merck. The terms of the MSAs range in initial duration from four years to ten years. The amounts included in the condensed consolidated statement of operations for the above MSAs include sales of $96 million and $95 million and related cost of sales of $101 million and $103 million for the second quarter of 2023 and 2022, respectively, and sales of $191 million and $194 million and related cost of sales of $208 million and $208 million for the first six months of 2023 and 2022, respectively. Amounts included in the condensed consolidated statement of operations for the TSAs were immaterial for the three and six months ended June 30, 2023 and June 30, 2022. The amounts due from Organon under all of the above agreements were $539 million and $511 million at June 30, 2023 and December 31, 2022, respectively, and are reflected in Other current assets . The amounts due to Organon under these agreements were $351 million and $345 million at June 30, 2023 and December 31, 2022, respectively, and are included in Accrued and other current liabilities .

Restructuring

Restructuring	6 Months Ended
	Jun. 30, 2023
Restructuring and Related Activities [Abstract]
Restructuring	Restructuring In 2019, Merck approved a global restructuring program (Restructuring Program) as part of a worldwide initiative focused on optimizing the Company’s manufacturing and supply network, as well as reducing its global real estate footprint. The actions 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 $3.9 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 $236 million and $258 million in the second quarter of 2023 and 2022, respectively, and $333 million and $384 million for the first six months of 2023 and 2022, respectively, related to restructuring program activities. Since inception of the Restructuring Program through June 30, 2023, Merck has recorded total pretax accumulated costs of approximately $3.7 billion. For the full year of 2023, the Company expects to record charges of approximately $550 million related to the Restructuring Program. For segment reporting, restructuring charges are unallocated expenses. The following tables summarize the charges related to restructuring program activities by type of cost: Three Months Ended June 30, 2023 Six Months Ended June 30, 2023 ($ in millions) Separation Accelerated Other Total Separation Accelerated Other Total Cost of sales $ — $ 22 $ 10 $ 32 $ — $ 43 $ 18 $ 61 Selling, general and administrative — — 52 52 — — 53 53 Research and development — — 1 1 — — 1 1 Restructuring costs 110 — 41 151 151 — 67 218 $ 110 $ 22 $ 104 $ 236 $ 151 $ 43 $ 139 $ 333 Three Months Ended June 30, 2022 Six Months Ended June 30, 2022 ($ in millions) Separation Accelerated Other Total Separation Accelerated Other Total Cost of sales $ — $ 17 $ 50 $ 67 $ — $ 35 $ 78 $ 113 Selling, general and administrative — 8 19 27 — 12 36 48 Research and development — 22 — 22 — 29 — 29 Restructuring costs 106 — 36 142 132 — 62 194 $ 106 $ 47 $ 105 $ 258 $ 132 $ 76 $ 176 $ 384 Separation costs are associated with actual headcount reductions, as well as involuntary 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 program. 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 2023 and 2022 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 six months ended June 30, 2023: ($ in millions) Separation Accelerated Other Total Restructuring reserves January 1, 2023 $ 479 $ — $ 34 $ 513 Expenses 151 43 139 333 (Payments) receipts, net (84) — (74) (158) Non-cash activity — (43) (68) (111) Restructuring reserves June 30, 2023 (1) $ 546 $ — $ 31 $ 577

Financial Instruments

Financial Instruments	6 Months Ended
	Jun. 30, 2023
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 of 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 Accumulated Other Comprehensive Loss ( 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. 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 Company also uses a balance sheet risk management program to mitigate the exposure of such assets and liabilities from the effects of volatility in foreign exchange. Merck principally utilizes forward exchange contracts to offset the effects of exchange in developed country currencies, primarily the euro, Japanese yen, British pound, Canadian dollar, Australian dollar and Swiss franc. For exposures in developing country currencies, including the Chinese renminbi, the Company will enter into forward contracts to 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 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 six months. The cash flows from these contracts are reported as operating activities in the Condensed Consolidated Statement of Cash Flows. 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 Condensed Consolidated Statement of Operations 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 June 30, Six Months Ended June 30, Three Months Ended June 30, Six Months Ended June 30, ($ in millions) 2023 2022 2023 2022 2023 2022 2023 2022 Net Investment Hedging Relationships Foreign exchange contracts $ — $ (31) $ 1 $ (46) $ — $ (1) $ 1 $ (2) Euro-denominated notes 21 (128) 73 (181) — — — — (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 at risk. The Company is not currently a party to any interest rate swaps. 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: June 30, 2023 December 31, 2022 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 Foreign exchange contracts Other current assets $ 200 $ — $ 5,976 $ 220 $ — $ 4,824 Foreign exchange contracts Other Assets 43 — 1,750 27 — 1,609 Foreign exchange contracts Accrued and other current liabilities — 62 2,245 — 101 2,691 Foreign exchange contracts Other Noncurrent Liabilities — 1 328 — 1 91 $ 243 $ 63 $ 10,299 $ 247 $ 102 $ 9,215 Derivatives Not Designated as Hedging Instruments Balance Sheet Caption Foreign exchange contracts Other current assets $ 222 $ — $ 8,838 $ 186 $ — $ 8,540 Foreign exchange contracts Accrued and other current liabilities — 181 10,112 — 307 10,926 $ 222 $ 181 $ 18,950 $ 186 $ 307 $ 19,466 $ 465 $ 244 $ 29,249 $ 433 $ 409 $ 28,681 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: June 30, 2023 December 31, 2022 ($ in millions) Asset Liability Asset Liability Gross amounts recognized in the condensed consolidated balance sheet $ 465 $ 244 $ 433 $ 409 Gross amounts subject to offset in master netting arrangements not offset in the condensed consolidated balance sheet (180) (180) (220) (220) Cash collateral received/posted (102) — (66) (19) Net amounts $ 183 $ 64 $ 147 $ 170 The table below provides information regarding the location and amount of pretax gains and losses of derivatives designated in fair value or cash flow hedging relationships: Three Months Ended June 30, Six Months Ended June 30, ($ in millions) 2023 2022 2023 2022 2023 2022 2023 2022 2023 2022 2023 2022 Financial Statement Caption in which Effects of Fair Value or Cash Flow Hedges are Recorded Sales Other (income) expense, net (1) Other comprehensive income (loss) Sales Other (income) expense, net (1) Other comprehensive income (loss) $ 15,035 $ 14,593 $ 172 $ 438 $ (17) $ 42 $ 29,522 $ 30,494 $ 259 $ 1,148 $ (132) $ 102 (Gain) loss on fair value hedging relationships: Interest rate swap contracts Hedged items — — — (4) — — — — — (14) — — Derivatives designated as hedging instruments — — — 1 — — — — — 4 — — Impact of cash flow hedging relationships: Foreign exchange contracts Amount of gain recognized in OCI on derivatives — — — — 194 403 — — — — 128 551 Increase in Sales as a result of AOCL reclassifications 24 172 — — (24) (172) 125 239 — — (125) (239) Interest rate contracts Amount of gain recognized in Other (income) expense, net on derivatives — — — — — — — — (1) (1) — — Amount of gain (loss) recognized in OCI on derivatives — — — — 13 — — — — — 13 (1) (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: Amount of Derivative Pretax (Gain) Loss Recognized in Income Three Months Ended June 30, Six Months Ended June 30, ($ in millions) 2023 2022 2023 2022 Derivatives Not Designated as Hedging Instruments Income Statement Caption Foreign exchange contracts (1) Other (income) expense, net $ (41) $ (64) $ (28) $ (36) Foreign exchange contracts (2) Sales (5) (36) (3) (38) (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. (2) These derivative contracts serve as economic hedges of forecasted transactions . At June 30, 2023, the Company estimates $83 million of pretax net unrealized gains on derivatives maturing within the next 12 months that hedge foreign currency denominated sales over that same period will be reclassified from AOCL to Sales . The amount ultimately reclassified to Sales may differ as foreign exchange rates change. Realized gains and losses are ultimately determined by actual exchange rates at maturity. Investments in Debt and Equity Securities Information on investments in debt and equity securities is as follows: June 30, 2023 December 31, 2022 Amortized Gross Unrealized Fair Amortized Gross Unrealized Fair ($ in millions) Gains Losses Gains Losses Commercial paper $ 561 $ — $ — $ 561 $ 498 $ — $ — $ 498 U.S. government and agency securities 256 — — 256 68 — — 68 Corporate notes and bonds 4 — — 4 3 — — 3 Total debt securities $ 821 $ — $ — $ 821 $ 569 $ — $ — $ 569 Publicly traded equity securities (1) 1,520 1,284 Total debt and publicly traded equity securities $ 2,341 $ 1,853 (1) Unrealized net losses (gains) of $71 million and $(267) million were recorded in Other (income) expense, net in the second quarter and first six months of 2023, respectively, on equity securities still held at June 30, 2023. Unrealized net (gains) losses of $(25) million and $194 million were recorded in Other (income) expense, net in the second quarter and first six months of 2022, respectively, on equity securities still held at June 30, 2022. At June 30, 2023 and June 30, 2022, the Company also had $949 million and $671 million, respectively, of equity investments without readily determinable fair values included in Other Assets . The Company records unrealized gains on these equity investments based on favorable observable price changes from transactions involving similar investments of the same investee and records unrealized losses based on unfavorable observable price changes, which are included in Other (income) expense, net . During the first six months of 2023 , the Company recorded unrealized gains of $3 million and unrealized losses of $23 million related to certain of these equity investments still held at June 30, 2023. During the first six months of 2022 , the Company recorded unrealized gains of $20 million and unrealized losses of $1 million related to certain of these investments still held at June 30, 2022. Cumulative unrealized gains and cumulative unrealized losses based on observable price changes for investments in equity investments without readily determinable fair values still held at June 30, 2023 were $287 million and $42 million, respectively. At June 30, 2023 and June 30, 2022, the Company also had $622 million and $805 million, respectively, recorded in Other Assets for equity securities held through ownership interests in investment funds. (Gains) losses recorded in Other (income) expense, net relating to these investment funds were $105 million and $302 million for the second quarter of 2023 and 2022, respectively, and were $(27) million and $811 million for the first six months of 2023 and 2022, respectively. Fair Value Measurements Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company uses a fair value hierarchy which maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value. There are three levels of inputs used to measure fair value with Level 1 having the highest priority and Level 3 having the lowest: Level 1 - Quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 - Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; Level 3 - Unobservable inputs that are supported by little or no market activity. Level 3 assets or liabilities are those whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques with significant unobservable inputs, as well as assets or liabilities for which the determination of fair value requires significant judgment or estimation. If the inputs used to measure the financial assets and liabilities fall within more than one level described above, the categorization is based on the lowest level input that is significant to the fair value measurement of the instrument. Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis Financial assets and liabilities measured at fair value on a recurring basis are summarized below: Fair Value Measurements Using Fair Value Measurements Using Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total ($ in millions) June 30, 2023 December 31, 2022 Assets Investments Commercial paper $ — $ 561 $ — $ 561 $ — $ 498 $ — $ 498 U.S. government and agency securities — 187 — 187 — — — — Publicly traded equity securities 1,184 — — 1,184 1,015 — — 1,015 1,184 748 — 1,932 1,015 498 — 1,513 Other assets (1) U.S. government and agency securities 69 — — 69 68 — — 68 Corporate notes and bonds 4 — — 4 3 — — 3 Publicly traded equity securities 336 — — 336 269 — — 269 409 — — 409 340 — — 340 Derivative assets (2) Forward exchange contracts — 316 — 316 — 218 — 218 Purchased currency options — 149 — 149 — 215 — 215 — 465 — 465 — 433 — 433 Total assets $ 1,593 $ 1,213 $ — $ 2,806 $ 1,355 $ 931 $ — $ 2,286 Liabilities Other liabilities Contingent consideration $ — $ — $ 349 $ 349 $ — $ — $ 456 $ 456 Derivative liabilities (2) Forward exchange contracts — 235 — 235 — 402 — 402 Written currency options — 9 — 9 — 7 — 7 — 244 — 244 — 409 — 409 Total liabilities $ — $ 244 $ 349 $ 593 $ — $ 409 $ 456 $ 865 (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 June 30, 2023 and December 31, 2022, Cash and cash equivalents included $4.9 billion and $11.3 billion of cash equivalents, respectively (which would be considered Level 2 in the fair value hierarchy). Contingent Consideration Summarized information about the changes in the fair value of liabilities for contingent consideration associated with business combinations is as follows: ($ in millions) 2023 2022 Fair value January 1 $ 456 $ 777 Changes in estimated fair value (1) 10 (114) Payments (117) (119) Other — (2) Fair value June 30 (2) $ 349 $ 542 (1) Recorded in Cost of sales, Research and development expenses, and Other (income) expense, net . Includes cumulative translation adjustments. (2) At June 30, 2023, $262 million 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 to present value the cash flows. Balance at June 30, 2023 includes $130 million recorded as a current liability for amounts expected to be paid within the next 12 months. The payments of contingent consideration in both periods relate to the Sanofi Pasteur MSD liabilities described above. 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 June 30, 2023, was $34.0 billion compared with a carrying value of $36.9 billion and at December 31, 2022, was $26.7 billion compared with a carrying value of $30.7 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 and government agencies. 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 $2.9 billion and $2.5 billion of accounts receivable as of June 30, 2023 and December 31, 2022, respectively, under these factoring arrangements, which reduced outstanding accounts receivable. The cash received from the financial institutions is reported within operating activities in the Condensed 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. As of June 30, 2023 and December 31, 2022, the Company had collected $44 million and $67 million, respectively, on behalf of the financial institutions, which is reflected as restricted cash in Other current assets and the related obligation to remit the cash within Accrued and other current liabilities . The Company remitted the cash to the financial institutions in July 2023 and January 2023, respectively. The net cash flows related to these collections are reported as financing activities in the Condensed 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 $102 million and $66 million at June 30, 2023 and December 31, 2022, respectively. The obligation to return such collateral is recorded in Accrued and other current liabilities

Inventories

Inventories	6 Months Ended
	Jun. 30, 2023
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consisted of: ($ in millions) June 30, 2023 December 31, 2022 Finished goods $ 1,841 $ 1,841 Raw materials and work in process 7,453 7,063 Supplies 269 238 Total 9,563 9,142 Decrease to LIFO cost (413) (293) $ 9,150 $ 8,849 Recognized as: Inventories $ 5,930 $ 5,911 Other Assets 3,220 2,938 Amounts recognized as Other Assets are comprised almost entirely of raw materials and work in process inventories. At June 30, 2023 and December 31, 2022, these amounts included $2.6 billion and $2.4 billion, respectively, of inventories not expected to be sold within one year. In addition, these amounts included $663 million and $516 million at June 30, 2023 and December 31, 2022, respectively, of inventories produced in preparation for product launches.

Long-Term Debt

Long-Term Debt	6 Months Ended
	Jun. 30, 2023
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt In May 2023, the Company issued $6.0 billion principal amount of senior unsecured notes consisting of $500 million of 4.05% notes due 2028, $750 million of 4.30% notes due 2030, $1.5 billion of 4.50% notes due 2033, $750 million of 4.90% notes due 2044, $1.5 billion of 5.00% notes due 2053, and $1.0 billion of 5.15% notes due 2063. The Company used a portion of the $5.9 billion net proceeds from this offering to fund a portion of the cash consideration paid for the acquisition of Prometheus and related fees and expenses, and used the remaining net proceeds for general corporate purposes including to repay commercial paper borrowings and other indebtedness with upcoming maturities.

Contingencies

Contingencies	6 Months Ended
	Jun. 30, 2023
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 Gardasil/Gardasil 9 Merck is a defendant in product liability lawsuits in the U.S. involving Gardasil (Human Papillomavirus Quadrivalent [Types 6, 11, 16 and 18] Vaccine, Recombinant) and Gardasil 9 (Human Papillomavirus 9-valent Vaccine, Recombinant). As of June 30, 2023, approximately 95 cases were filed and pending against Merck in either federal or state court. In these actions, plaintiffs allege, among other things, that they suffered various personal injuries after vaccination with Gardasil or Gardasil 9, with postural orthostatic tachycardia syndrome as a predominate alleged injury. In August 2022, the Judicial Panel on Multidistrict Litigation ordered that Gardasil/Gardasil 9 product liability cases pending in federal courts nationwide be transferred to Judge Robert J. Conrad in the Western District of North Carolina for coordinated pre-trial proceedings. There are fewer than 15 product liability cases pending outside the U.S. Governmental Proceedings Inflation Reduction Act On June 6, 2023, Merck filed a complaint in the U.S. District Court for the District of Columbia against the U.S. government regarding the Inflation Reduction Act’s “Drug Price Negotiation Program” for Medicare (the Program). This litigation seeks relief from the Program by challenging its constitutionality as violative of the First and Fifth Amendments to the U.S. Constitution. Other Governmental Proceedings As previously disclosed, from time to time, the Company’s subsidiaries in China 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, Merck Sharp & Dohme, LLC. (MSD), Schering Corporation, Schering-Plough Corporation, and MSP Singapore Company LLC (collectively, the Merck Defendants) were defendants in a number of 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 were consolidated in a federal multidistrict litigation (the Zetia MDL) before Judge Rebecca Beach Smith in the Eastern District of Virginia. In 2020 and 2021, United Healthcare Services, Inc., Humana Inc., Centene Corporation and others, and Kaiser Foundation Health Plan, Inc. (collectively, the Insurer Plaintiffs), each filed a lawsuit in a jurisdiction outside of the Eastern District of Virginia against the Merck Defendants and others, making similar allegations as those made in the Zetia MDL, as well as additional allegations about Vytorin. These cases have been transferred to the Eastern District of Virginia to proceed with the Zetia MDL and remain pending. In February 2022, the Insurer Plaintiffs filed amended complaints. In March 2022, the Merck Defendants, jointly with other defendants, moved to dismiss certain aspects of the Insurer Plaintiffs’ complaints, including any claims for Vytorin damages. That motion to dismiss the Vytorin-related claims is still pending. As previously disclosed, in April 2023, the Merck Defendants reached settlements with the direct purchaser and retailer plaintiffs and a proposed settlement, subject to court approval, with the indirect purchaser class. Under these agreements, Merck agreed to pay $572.5 million to resolve the direct purchaser, retailer, and indirect purchaser plaintiffs’ claims, which was recorded as an expense in the Company’s first quarter 2023 financial results. On June 6, 2023, the court granted preliminary approval of the indirect purchaser class settlement and scheduled a fairness hearing for September 21, 2023. Qui Tam Litigation As previously disclosed, in June 2012, the U.S. District Court for the Eastern District of Pennsylvania unsealed a complaint that had been filed against the Company under the federal False Claims Act by two former employees alleging, among other things, that the Company defrauded the U.S. government by falsifying data in connection with a clinical study conducted on the mumps component of the Company’s M-M-R II vaccine. The complaint alleges the fraud took place between 1999 and 2001. The U.S. government had the right to participate in and take over the prosecution of this lawsuit but notified the court that it declined to exercise that right. The two former employees are pursuing the lawsuit without the involvement of the U.S. government. In addition, as previously disclosed, two putative class action lawsuits on behalf of direct purchasers of the M-M-R II vaccine, which charge that the Company misrepresented the efficacy of the M-M-R II vaccine in violation of federal antitrust laws and various state consumer protection laws, are pending in the Eastern District of Pennsylvania. In September 2014, the court denied Merck’s motion to dismiss the False Claims Act suit and granted in part and denied in part its motion to dismiss the then-pending antitrust suit. As a result, both the False Claims Act suit and the antitrust suits proceeded into discovery, which is complete, and the parties filed and briefed cross-motions for summary judgment. On July 27, 2023, in the False Claims Act case, the court denied relators’ motion for summary judgment, granted two of the Company’s motions for summary judgment, and denied the Company’s remaining motions for summary judgment as moot. The court entered judgment in favor of the Company and dismissed relators’ amended complaint in full with prejudice. Relators can appeal that decision. In the antitrust case, the court granted the Company’s motion for summary judgment as to plaintiffs’ state law claims and denied the motion as to plaintiffs’ antitrust claim. Plaintiffs’ antitrust claim will proceed in litigation. Patent Litigation From time to time, generic manufacturers of pharmaceutical products file abbreviated New Drug Applications (NDAs) with the U.S. Food and Drug Administration (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 accounted for as business combinations, potentially significant intangible asset impairment charges. Bridion — As previously disclosed, 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 were consolidated. The West Virginia case was jointly dismissed with prejudice on August 8, 2022 in favor of proceeding in New Jersey. The remaining defendants in the New Jersey action stipulated to infringement of the asserted claims and withdrew all remaining claims and defenses other than a defense seeking to shorten the patent term extension (PTE) of the sugammadex patent to December 2022. The U.S. District Court for the District of New Jersey held a one-day trial on December 19, 2022 on this remaining PTE calculation defense and held closing arguments on February 3, 2023. While the New Jersey action was pending, the Company settled with five 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. The Company agreed to stay the lawsuit filed against two generic companies, which in exchange agreed to be bound by a judgment on the merits of the consolidated action in the District of New Jersey. One of the generic companies in the consolidated action requested dismissal of the action against it and the Company did not oppose this request, which was subsequently granted by the court. The Company does not expect this company to bring its generic version of Bridion to the market before January 2026 or later, depending on any applicable pediatric exclusivity. On June 13, 2023, the U.S. District Court for the District of New Jersey ruled in Merck’s favor. The court held that Merck’s calculation of PTE for the sugammadex patent covering the compound is not invalid and that the U.S. Patent & Trademark Office correctly granted a full 5-year extension. This ruling affirms and validates Merck’s U.S. patent protection for Bridion through at least January 2026. On June 29, 2023, the U.S. District Court for the District of New Jersey issued a final judgment prohibiting the FDA from approving any of the pending or tentatively approved generic applications until January 27, 2026, except for any subsequent agreements between Defendants and Merck or further order by the court. Januvia, Janumet, Janumet XR — As previously disclosed, the FDA granted pediatric exclusivity with respect to Januvia (sitagliptin), Janumet (sitagliptin/metformin HCI), and Janumet XR (sitagliptin and metformin HCl extended-release), 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 extended exclusivity on these products to January 2023. 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 that expires in May 2027, including pediatric exclusivity (2027 salt/polymorph patent). 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. The Company also filed a patent infringement lawsuit against Mylan in the U.S. District Court for the Northern District of West Virginia. Prior to the beginning of the scheduled 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, a bench trial was held in December 2021 in the U.S. District Court for the Northern District of West Virginia, and the closing arguments were held in April 2022. In September 2022, the U.S. District Court for the Northern District of West Virginia issued a decision in the Company’s favor, upholding all asserted patent claims. Mylan (now Viatris) appealed to the U.S. Court of Appeals for the Federal Circuit. The parties have now settled the matter, and Viatris has agreed to voluntarily dismiss the appeal following entry of an amended final judgment by the district court. In total, the Company has settled with 25 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. In March 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 NDA seeking approval of its sitagliptin tablets. In December 2022, the parties reached settlement that included dismissal of the case without prejudice enabling Zydus to seek final approval of a non-automatically substitutable product containing a different form of sitagliptin than that used in Januvia . In January 2023, the Company received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying the Company that Zydus filed a NDA seeking approval of sitagliptin/metformin HCl tablets and certifying that no valid or enforceable claim of any of the patents listed in FDA’s Orange Book for Janumet will be infringed by the proposed Zydus product. In March 2023, the parties reached settlement enabling Zydus to seek final approval of a non-automatically substitutable product containing a different form of sitagliptin than that used in Janumet. As a result of these favorable court rulings and settlement agreements related to the later expiring 2027 salt/polymorph patent directed to the specific sitagliptin salt form of the products, the Company expects that Januvia and Janumet will not lose market exclusivity in the U.S. until May 2026 and Janumet XR will not lose market exclusivity in the U.S. until July 2026 , although another non-automatically substitutable form of sitagliptin could be available prior to 2026 . Supplementary Protection Certificates (SPCs) for Janumet expired in April 2023 for the majority of European countries. Prior to expiration, generic companies sought revocation of the Janumet SPCs in a number of European countries. In February 2022, a Finnish court referred certain questions to the Court of Justice of the European Union (CJEU) that could determine the validity of the Janumet SPCs in Europe, for which an oral hearing was held on March 8, 2023, and an Advocate General Opinion is expected in the third quarter with a decision in the fourth quarter of 2023. If the CJEU renders a decision that negatively impacts the validity of the Janumet SPCs throughout Europe, generic companies that were prevented from launching products during the SPC period in certain European countries may have an action for damages. Those countries include Belgium, Czech Republic, Ireland, Finland, France, Slovakia and Switzerland. If the Janumet SPCs are ultimately upheld, the Company has reserved its rights related to the pursuit of damages for those countries where a generic launched prior to expiry of the Janumet SPC. Keytruda — The Company filed a complaint against The Johns Hopkins University (JHU) on November 29, 2022, in the U.S. District Court of Maryland. This action concerns patents emerging from a joint research collaboration between Merck and JHU regarding the use of pembrolizumab, which Merck sells under the trade name Keytruda . Merck and JHU partnered to design and conduct a clinical study administering Keytruda to cancer patients having tumors that had the genetic biomarker known as microsatellite instability-high (MSI-H). After the conclusion of the study, JHU secured U.S. patents citing the joint research study. Merck alleges that JHU has breached the collaboration agreement by filing and obtaining these patents without informing or involving Merck and then licensing the patents to others. Merck therefore brought this action for breach of contract, declaratory judgment of noninfringement, and promissory estoppel. JHU answered the complaint on April 13, 2023, denying Merck’s claims, and counterclaiming for willful infringement of five issued U.S. patents, including a demand for damages. Lynparza — In December 2022, AstraZeneca Pharmaceuticals LP received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying AstraZeneca that Natco Pharma Limited (Natco) has filed an application to the FDA seeking pre-patent expiry approval to sell generic versions of Lynparza (olaparib) tablet. In February 2023, AstraZeneca and the Company filed a patent infringement lawsuit in the U.S. District Court for the District of New Jersey against Natco. This lawsuit, which asserts one or more patents covering olaparib, automatically stays FDA approval of the generic application until June 2025 or until an adverse court decision, if any, whichever may occur earlier. 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. Other Matters As previously disclosed, the Company was involved in an arbitration with Johnson & Johnson with respect to two agreements pursuant to which Merck was supporting the manufacture and supply of Johnson & Johnson’s SARS-CoV-2/COVID-19 vaccine and vaccine drug product. The arbitration has been settled with no material impact to the Company’s financial statements. 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 scope of its litigation; the number of cases being brought against the Company; the costs and outcomes of completed trials and the most current information regarding anticipated timing, progression, and related costs of pre-trial activities and trials in the associated litigation. The amount of legal defense reserves as of June 30, 2023 and December 31, 2022 of approximately $225 million and $230 million, respectively, represents the Company’s best estimate of the minimum amount of defense costs to be incurred in connection with its outstanding litigation; however, events such as additional trials and other events that could arise in the course of its litigation could affect the ultimate amount of legal defense costs to be incurred by the Company. The Company will continue to monitor its legal defense costs and review the adequacy of the associated reserves and may determine to increase the reserves at any time in the future if, based upon the factors set forth, it believes it would be appropriate to do so.

Equity

Equity	6 Months Ended
	Jun. 30, 2023
Equity [Abstract]
Equity	Equity Three Months Ended June 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 April 1, 2022 3,577 $ 1,788 $ 44,275 $ 56,252 $ (4,369) 1,049 $ (57,063) $ 70 $ 40,953 Net income attributable to Merck & Co., Inc. — — — 3,944 — — — — 3,944 Other comprehensive income, net of taxes — — — — 42 — — — 42 Cash dividends declared on common stock ($0.69 per share) — — — (1,759) — — — — (1,759) Share-based compensation plans and other — — (160) — — (5) 293 — 133 Net income attributable to noncontrolling interests — — — — — — — 5 5 Balance at June 30, 2022 3,577 $ 1,788 $ 44,115 $ 58,437 $ (4,327) 1,044 $ (56,770) $ 75 $ 43,318 Balance at April 1, 2023 3,577 $ 1,788 $ 44,467 $ 62,039 $ (4,883) 1,040 $ (56,577) $ 71 $ 46,905 Net loss attributable to Merck & Co., Inc. — — — (5,975) — — — — (5,975) Other comprehensive loss, net of taxes — — — — (17) — — — (17) Cash dividends declared on common stock ($0.73 per share) — — — (1,866) — — — — (1,866) Treasury stock shares purchased — — — — — 3 (338) — (338) Share-based compensation plans and other — — (248) — — (5) 303 — 55 Net income attributable to noncontrolling interests — — — — — — — 3 3 Distributions attributable to noncontrolling interests — — — — — — — (25) (25) Balance at June 30, 2023 3,577 $ 1,788 $ 44,219 $ 54,198 $ (4,900) 1,038 $ (56,612) $ 49 $ 38,742 Six Months Ended June 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, 2022 3,577 $ 1,788 $ 44,238 $ 53,696 $ (4,429) 1,049 $ (57,109) $ 73 $ 38,257 Net income attributable to Merck & Co., Inc. — — — 8,254 — — — — 8,254 Other comprehensive income, net of taxes — — — — 102 — — — 102 Cash dividends declared on common stock ($1.38 per share) — — — (3,513) — — — — (3,513) Share-based compensation plans and other — — (123) — — (5) 339 — 216 Net income attributable to noncontrolling interests — — — — — — — 2 2 Balance at June 30, 2022 3,577 $ 1,788 $ 44,115 $ 58,437 $ (4,327) 1,044 $ (56,770) $ 75 $ 43,318 Balance at January 1, 2023 3,577 $ 1,788 $ 44,379 $ 61,081 $ (4,768) 1,039 $ (56,489) $ 67 $ 46,058 Net loss attributable to Merck & Co., Inc. — — — (3,154) — — — — (3,154) Other comprehensive loss, net of taxes — — — — (132) — — — (132) Cash dividends declared on common stock ($1.46 per share) — — — (3,729) — — — — (3,729) Treasury stock shares purchased — — — — — 4 (487) — (487) Share-based compensation plans and other — — (160) — — (5) 364 — 204 Net income attributable to noncontrolling interests — — — — — — — 7 7 Distributions attributable to noncontrolling interests — — — — — — — (25) (25) Balance at June 30, 2023 3,577 $ 1,788 $ 44,219 $ 54,198 $ (4,900) 1,038 $ (56,612) $ 49 $ 38,742

Pension and Other Postretiremen

Pension and Other Postretirement Benefit Plans	6 Months Ended
	Jun. 30, 2023
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 (credit) of such plans consisted of the following components: Three Months Ended Six Months Ended 2023 2022 2023 2022 ($ in millions) U.S. International U.S. International U.S. International U.S. International Service cost $ 76 $ 50 $ 99 $ 72 $ 152 $ 99 $ 198 $ 147 Interest cost 133 75 103 37 266 149 206 75 Expected return on plan assets (185) (130) (197) (98) (372) (257) (393) (199) Amortization of unrecognized prior service cost (credit) — 16 (8) (3) (1) 12 (16) (7) Net (gain) loss amortization — (1) 56 25 — (2) 112 50 Termination benefits 1 — 1 — 1 — 1 — Curtailments 2 — 4 — 5 — 8 — Settlements 5 — 101 — 26 — 101 — $ 32 $ 10 $ 159 $ 33 $ 77 $ 1 $ 217 $ 66 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 Six Months Ended ($ in millions) 2023 2022 2023 2022 Service cost $ 8 $ 12 $ 17 $ 25 Interest cost 16 11 31 23 Expected return on plan assets (16) (21) (32) (43) Amortization of unrecognized prior service credit (12) (14) (25) (29) Net gain amortization (11) (11) (21) (21) $ (15) $ (23) $ (30) $ (45) 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 activities, curtailments were recorded on certain pension plans. In addition, lump sum payments to U.S. pension plan participants triggered partial settlement charges in the second quarter and first six months of both 2023 and 2022. These partial settlements triggered remeasurements of some of the Company’s U.S. pension plans. Remeasurements during the first six months of 2023 resulted in an increase of $47 million to net pension liabilities and 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 related to restructuring actions.

Other (Income) Expense, Net

Other (Income) Expense, Net	6 Months Ended
	Jun. 30, 2023
Other Income and Expenses [Abstract]
Other (Income) Expense, Net	Other (Income) Expense, Net Other (income) expense, net, consisted of: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Interest income $ (109) $ (15) $ (221) $ (22) Interest expense 277 240 519 483 Exchange losses 62 86 122 124 Loss (income) from investments in equity securities, net (1) 175 284 (274) 991 Net periodic defined benefit plan (credit) cost other than service cost (111) (27) (226) (148) Other, net (122) (130) 339 (280) $ 172 $ 438 $ 259 $ 1,148 (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 gains and losses from ownership interests in investment funds are accounted for on a one quarter lag. Other, net (as reflected in the table above) in the first six months of 2023 includes a $572.5 million charge related to settlements with certain plaintiffs in the Zetia antitrust litigation (see Note 9). Interest paid for both the six months ended June 30, 2023 and 2022 was $449 million.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesThe income tax provision of $637 million and $1.5 billion for the second quarter and first six months of 2023, respectively, on pretax losses of $5.3 billion and $1.7 billion, respectively, resulted in effective income tax rates of (11.9)% and (86.8)%, respectively. The second quarter 2023 effective tax rate includes the impact of a charge for the acquisition of Prometheus for which no tax benefit was recognized, which unfavorably affected the tax rate by 25.1 percentage points, as well as the favorable impact of net unrealized losses from investments in equity securities, which were taxed at the U.S. tax rate. The effective income tax rate for the first six months of 2023 includes a 101.9 percentage point combined unfavorable impact of charges for the acquisitions of Prometheus and Imago for which no tax benefits were recognized, as well as higher foreign taxes, the impact of the R&D capitalization provision of the Tax Cuts and Jobs Act of 2017 (TCJA) on the Company’s U.S. global intangible low-taxed income inclusion, and net unrealized gains from investments in equity securities, which were taxed at the U.S. tax rate, partially offset by higher foreign tax credits. The effective income tax rates of 12.0% for the second quarter of 2022 and 11.7% for the first six months of 2022 reflect the favorable impact of net unrealized losses from investments in equity securities, which were taxed at the U.S. tax rate.The Internal Revenue Service (IRS) is currently conducting examinations of the Company’s tax returns for the years 2017 and 2018, including the one-time transition tax enacted under the TCJA. If the IRS disagrees with the Company’s transition tax position, it may result in a significant tax liability.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The calculations of (loss) earnings per share are as follows: Three Months Ended Six Months Ended ($ and shares in millions except per share amounts) 2023 2022 2023 2022 Net (Loss) Income Attributable to Merck & Co., Inc. $ (5,975) $ 3,944 $ (3,154) $ 8,254 Average common shares outstanding 2,539 2,531 2,539 2,529 Common shares issuable (1) — 9 — 9 Average common shares outstanding assuming dilution 2,539 2,540 2,539 2,538 Basic (Loss) Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders $ (2.35) $ 1.56 $ (1.24) $ 3.26 (Loss) Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders $ (2.35) $ 1.55 $ (1.24) $ 3.25 (1) Issuable primarily under share-based compensation plans.

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	6 Months Ended
	Jun. 30, 2023
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 June 30, ($ in millions) Derivatives Employee Foreign Currency Accumulated Other Balance April 1, 2022, net of taxes $ 207 $ (2,711) $ (1,865) $ (4,369) Other comprehensive income (loss) before reclassification adjustments, pretax 403 168 (365) 206 Tax (85) (35) (22) (142) Other comprehensive income (loss) before reclassification adjustments, net of taxes 318 133 (387) 64 Reclassification adjustments, pretax (171) (1) 144 (2) — (27) Tax 36 (31) — 5 Reclassification adjustments, net of taxes (135) 113 — (22) Other comprehensive income (loss), net of taxes 183 246 (387) 42 Balance June 30, 2022, net of taxes $ 390 $ (2,465) $ (2,252) $ (4,327) Balance April 1, 2023, net of taxes $ (60) $ (2,458) $ (2,365) $ (4,883) Other comprehensive income (loss) before reclassification adjustments, pretax 194 (6) (115) 73 Tax (41) 1 (22) (62) Other comprehensive income (loss) before reclassification adjustments, net of taxes 153 (5) (137) 11 Reclassification adjustments, pretax (11) (1) (23) (2) — (34) Tax 3 3 — 6 Reclassification adjustments, net of taxes (8) (20) — (28) Other comprehensive income (loss), net of taxes 145 (25) (137) (17) Balance June 30, 2023, net of taxes $ 85 $ (2,483) $ (2,502) $ (4,900) Six Months Ended June 30, ($ in millions) Derivatives Employee Foreign Currency Accumulated Other Balance January 1, 2022, net of taxes $ 144 $ (2,743) $ (1,830) $ (4,429) Other comprehensive income (loss) before reclassification adjustments, pretax 551 169 (383) 337 Tax (116) (37) (39) (192) Other comprehensive income (loss) before reclassification adjustments, net of taxes 435 132 (422) 145 Reclassification adjustments, pretax (239) (1) 189 (2) — (50) Tax 50 (43) — 7 Reclassification adjustments, net of taxes (189) 146 — (43) Other comprehensive income (loss), net of taxes 246 278 (422) 102 Balance June 30, 2022, net of taxes $ 390 $ (2,465) $ (2,252) $ (4,327) Balance January 1, 2023, net of taxes $ 73 $ (2,408) $ (2,433) $ (4,768) Other comprehensive income (loss) before reclassification adjustments, pretax 128 (53) (36) 39 Tax (27) 3 (42) (66) Other comprehensive income (loss) before reclassification adjustments, net of taxes 101 (50) (78) (27) Reclassification adjustments, pretax (113) (1) (30) (2) 9 (134) Tax 24 5 — 29 Reclassification adjustments, net of taxes (89) (25) 9 (105) Other comprehensive income (loss), net of taxes 12 (75) (69) (132) Balance June 30, 2023, net of taxes $ 85 $ (2,483) $ (2,502) $ (4,900) (1) Primarily relates to foreign currency cash flow hedges that were reclassified from AOCL to Sales . (2) Includes net amortization of prior service cost, actuarial gains and losses, settlements and curtailments included in net periodic benefit cost (see Note 11)

Segment Reporting

Segment Reporting	6 Months Ended
	Jun. 30, 2023
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting The Company’s operations are principally managed on a product basis and include two operating segments, Pharmaceutical and Animal Health, 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. 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, animal producers, farmers and pet owners. Sales of the Company’s products were as follows: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 ($ 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 $ 3,863 $ 2,408 $ 6,271 $ 3,197 $ 2,055 $ 5,252 $ 7,348 $ 4,718 $ 12,065 $ 5,976 $ 4,085 $ 10,061 Alliance revenue-Lynparza (1) 144 166 310 143 132 275 286 299 585 283 257 541 Alliance revenue-Lenvima (1) 163 79 242 128 103 231 316 158 474 284 175 459 Welireg 49 2 50 27 — 27 90 3 92 45 — 45 Alliance revenue-Reblozyl (2) 36 11 47 28 5 33 66 24 90 55 30 86 Vaccines Gardasil/Gardasil 9 464 1,994 2,458 428 1,245 1,674 880 3,550 4,430 846 2,287 3,133 ProQuad/M-M-R II /Varivax 447 135 582 434 143 578 868 242 1,109 805 243 1,047 RotaTeq 93 37 131 98 75 173 273 155 428 273 116 389 Vaxneuvance 147 20 168 11 — 12 241 33 274 16 1 16 Pneumovax 23 23 69 92 94 59 153 63 125 188 212 114 325 Vaqta 29 13 42 16 19 35 59 23 82 45 25 71 Hospital Acute Care Bridion 299 203 502 237 190 426 576 413 989 432 389 821 Prevymis 61 82 143 47 56 103 116 157 273 87 110 197 Dificid 68 8 76 63 3 66 130 11 141 113 6 119 Primaxin (2) 56 53 — 64 64 2 132 133 1 122 122 Noxafil 11 45 55 16 45 60 25 91 116 25 92 118 Zerbaxa 30 24 54 22 24 46 57 47 104 40 36 76 Cardiovascular Alliance revenue-Adempas/Verquvo (3) 70 (2) 68 88 10 98 153 14 167 159 11 170 Adempas — 65 65 — 63 63 — 125 125 — 124 124 Virology Lagevrio 2 201 203 — 1,177 1,177 — 595 595 1,523 2,901 4,424 Isentress/Isentress HD 56 80 136 67 80 147 108 151 259 128 177 305 Neuroscience Belsomra 21 42 63 19 50 69 37 82 119 39 98 137 Immunology Simponi — 180 180 — 181 181 — 359 359 — 366 366 Remicade — 48 48 — 53 53 — 99 99 — 114 114 Diabetes Januvia 243 267 511 301 455 756 514 548 1,062 626 909 1,535 Janumet 82 272 354 105 371 476 138 544 683 168 762 931 Other pharmaceutical (4) 171 382 553 157 372 528 342 793 1,138 317 814 1,131 Total Pharmaceutical segment sales 6,570 6,887 13,457 5,726 7,030 12,756 12,688 13,491 26,179 12,498 14,364 26,863 Animal Health: Livestock 165 643 807 164 662 826 338 1,318 1,656 335 1,322 1,658 Companion Animal 310 339 649 313 328 641 618 673 1,291 616 676 1,291 Total Animal Health segment sales 475 982 1,456 477 990 1,467 956 1,991 2,947 951 1,998 2,949 Total segment sales 7,045 7,869 14,913 6,203 8,020 14,223 13,644 15,482 29,126 13,449 16,362 29,812 Other (5) (27) 149 122 35 335 370 32 364 396 128 555 682 $ 7,018 $ 8,018 $ 15,035 $ 6,238 $ 8,355 $ 14,593 $ 13,676 $ 15,846 $ 29,522 $ 13,577 $ 16,917 $ 30,494 U.S. plus international may not equal total due to rounding. (1) Alliance revenue for Lynparza and Lenvima represents Merck’s share of profits, which are product sales net of cost of sales and commercialization costs (see Note 3). (2) Alliance revenue for Reblozyl represents royalties and, for the first six months of 2022, also includes the receipt of a regulatory approval milestone payment (see Note 3). (3) Alliance revenue for Adempas/Verquvo 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 3). (4) Other pharmaceutical primarily reflects sales of other human health pharmaceutical products, including products within the franchises not listed separately. (5) Other is primarily comprised of miscellaneous corporate revenue, including revenue hedging activities which increased sales by $128 million and $277 million for the six months ended June 30, 2023 and 2022, respectively, as well as revenue from third-party manufacturing arrangements (including sales to Organon). Other for the six months ended June 30, 2023 and 2022 also includes $54 million and $146 million, respectively, related to upfront and milestone payments received by Merck for out-licensing arrangements. 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 $3.2 billion and $3.0 billion for the three months ended June 30, 2023 and 2022, respectively, and $6.3 billion and $5.9 billion for the six months ended June 30, 2023 and 2022, respectively. Consolidated sales by geographic area where derived are as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 United States $ 7,018 $ 6,238 $ 13,676 $ 13,577 Europe, Middle East and Africa 3,348 3,582 6,651 7,942 China 1,913 1,372 3,628 2,515 Asia Pacific (other than China and Japan) 848 1,008 1,694 1,938 Japan 675 1,114 1,434 2,103 Latin America 742 642 1,403 1,249 Other 491 637 1,036 1,170 $ 15,035 $ 14,593 $ 29,522 $ 30,494 A reconciliation of segment profits to (Loss) Income Before Taxes is as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Segment profits: Pharmaceutical segment $ 9,854 $ 9,173 $ 18,993 $ 18,673 Animal Health segment 467 571 1,032 1,156 Total segment profits 10,321 9,744 20,025 19,829 Other profits 19 260 184 454 Unallocated: Interest income 109 15 221 22 Interest expense (277) (240) (519) (483) Amortization (477) (463) (1,020) (1,163) Depreciation (376) (431) (775) (809) Research and development (13,194) (2,652) (17,341) (5,097) Restructuring costs (151) (142) (218) (194) Charge for Zetia antitrust litigation settlements — — (573) — Other unallocated, net (1,309) (1,604) (1,669) (3,211) $ (5,335) $ 4,487 $ (1,685) $ 9,348 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 arrangements. Other unallocated, net, includes expenses from corporate and manufacturing cost centers, 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.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pay vs Performance Disclosure
Net (Loss) Income Attributable to Merck & Co., Inc.	$ (5,975)	$ 3,944	$ (3,154)	$ 8,254

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Jun. 30, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Basis of Presentation (Policies

Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2023
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 24, 2023. 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.
Recently Adopted Accounting Standard	Recently Adopted Accounting Standards In October 2021, the FASB issued amended guidance that requires acquiring entities to recognize and measure contract assets and liabilities in a business combination in accordance with existing revenue recognition guidance. The Company adopted the guidance effective January 1, 2023. The adoption of this guidance did not have an impact on the Company’s consolidated financial statements for prior acquisitions; however, the impact in future periods will be dependent upon the contract assets and contract liabilities acquired in future business combinations. In June 2022, the FASB issued guidance related to the fair value measurement of an equity security subject to contractual restrictions that prohibit the sale of the equity security. The new guidance also introduces new disclosure requirements for equity securities subject to contractual sale restrictions that are measured at fair value. The Company adopted the guidance effective July 1, 2023. There was no impact to the Company’s consolidated financial statements upon adoption.
Legal Costs	Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable.

Collaborative Arrangements (Tab

Collaborative Arrangements (Tables)	6 Months Ended
	Jun. 30, 2023
Collaborative Arrangements [Abstract]
Collaboration Arrangements	Summarized financial information related to this collaboration is as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Alliance revenue - Lynparza $ 310 $ 275 $ 585 $ 541 Alliance revenue - Koselugo 25 24 48 33 Total alliance revenue $ 335 $ 299 $ 633 $ 574 Cost of sales (1) 78 62 148 361 Selling, general and administrative 51 46 98 90 Research and development 22 25 43 51 ($ in millions) June 30, 2023 December 31, 2022 Receivables from AstraZeneca included in Other current assets $ 332 $ 303 Payables to AstraZeneca included in Accrued and other current liabilities (2) 260 123 Payables to AstraZeneca included in Other Noncurrent Liabilities (2) 600 600 (1) Represents amortization of capitalized milestone payments. Amount in the first six months of 2022 includes $250 million of cumulative amortization catch-up expense as noted above. (2) Includes accrued milestone payments. Summarized financial information related to this collaboration is as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Alliance revenue - Lenvima $ 242 $ 231 $ 474 $ 459 Cost of sales (1) 57 53 183 106 Selling, general and administrative 48 42 99 73 Research and development 17 47 56 104 ($ in millions) June 30, 2023 December 31, 2022 Receivables from Eisai included in Other current assets $ 242 $ 214 (1) Represents amortization of capitalized milestone payments. Amount in the first six months of 2023 includes $72 million of cumulative amortization catch-up expense as noted above. Summarized financial information related to this collaboration is as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Alliance revenue - Adempas/Verquvo $ 68 $ 98 $ 167 $ 170 Net sales of Adempas recorded by Merck 65 63 125 124 Net sales of Verquvo recorded by Merck 9 6 16 9 Total sales $ 142 $ 167 $ 308 $ 303 Cost of sales (1) 56 54 113 103 Selling, general and administrative 34 42 67 65 Research and development 25 17 50 34 ($ in millions) June 30, 2023 December 31, 2022 Receivables from Bayer included in Other current assets $ 144 $ 143 Payables to Bayer included in Accrued and other current liabilities 82 80 (1) Includes amortization of intangible assets. Summarized financial information related to this collaboration is as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Net sales of Lagevrio recorded by Merck $ 203 $ 1,177 $ 595 $ 4,424 Cost of sales (1)(2) 193 615 414 2,341 Selling, general and administrative (2) 24 34 51 69 Research and development (2) 10 30 26 56 ($ in millions) June 30, 2023 December 31, 2022 Receivables from Ridgeback included in Other current assets (3) $ 51 $ — Payables to Ridgeback included in Accrued and other current liabilities (4) 30 348 (1) Includes royalty expense, amortization of capitalized milestone payments and inventory reserves. (2) Expenses include an allocation for overhead charges. (3) Includes partner advances. (4) Includes accrued royalties. Amount at December 31, 2022 also includes an accrued milestone payment .

Restructuring (Tables)

Restructuring (Tables)	6 Months Ended
	Jun. 30, 2023
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 June 30, 2023 Six Months Ended June 30, 2023 ($ in millions) Separation Accelerated Other Total Separation Accelerated Other Total Cost of sales $ — $ 22 $ 10 $ 32 $ — $ 43 $ 18 $ 61 Selling, general and administrative — — 52 52 — — 53 53 Research and development — — 1 1 — — 1 1 Restructuring costs 110 — 41 151 151 — 67 218 $ 110 $ 22 $ 104 $ 236 $ 151 $ 43 $ 139 $ 333 Three Months Ended June 30, 2022 Six Months Ended June 30, 2022 ($ in millions) Separation Accelerated Other Total Separation Accelerated Other Total Cost of sales $ — $ 17 $ 50 $ 67 $ — $ 35 $ 78 $ 113 Selling, general and administrative — 8 19 27 — 12 36 48 Research and development — 22 — 22 — 29 — 29 Restructuring costs 106 — 36 142 132 — 62 194 $ 106 $ 47 $ 105 $ 258 $ 132 $ 76 $ 176 $ 384
Charges and Spending Relating to Restructuring Activities by Program	The following table summarizes the charges and spending relating to restructuring program activities for the six months ended June 30, 2023: ($ in millions) Separation Accelerated Other Total Restructuring reserves January 1, 2023 $ 479 $ — $ 34 $ 513 Expenses 151 43 139 333 (Payments) receipts, net (84) — (74) (158) Non-cash activity — (43) (68) (111) Restructuring reserves June 30, 2023 (1) $ 546 $ — $ 31 $ 577

Financial Instruments (Tables)

Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Effect of Net Investment Hedges on OCI and the Consolidated Statement of Operations	The effects of the Company’s net investment hedges on OCI and the Condensed Consolidated Statement of Operations 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 June 30, Six Months Ended June 30, Three Months Ended June 30, Six Months Ended June 30, ($ in millions) 2023 2022 2023 2022 2023 2022 2023 2022 Net Investment Hedging Relationships Foreign exchange contracts $ — $ (31) $ 1 $ (46) $ — $ (1) $ 1 $ (2) Euro-denominated notes 21 (128) 73 (181) — — — — (1) No amounts were reclassified from AOCL into income related to the sale of a subsidiary.
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: June 30, 2023 December 31, 2022 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 Foreign exchange contracts Other current assets $ 200 $ — $ 5,976 $ 220 $ — $ 4,824 Foreign exchange contracts Other Assets 43 — 1,750 27 — 1,609 Foreign exchange contracts Accrued and other current liabilities — 62 2,245 — 101 2,691 Foreign exchange contracts Other Noncurrent Liabilities — 1 328 — 1 91 $ 243 $ 63 $ 10,299 $ 247 $ 102 $ 9,215 Derivatives Not Designated as Hedging Instruments Balance Sheet Caption Foreign exchange contracts Other current assets $ 222 $ — $ 8,838 $ 186 $ — $ 8,540 Foreign exchange contracts Accrued and other current liabilities — 181 10,112 — 307 10,926 $ 222 $ 181 $ 18,950 $ 186 $ 307 $ 19,466 $ 465 $ 244 $ 29,249 $ 433 $ 409 $ 28,681
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: June 30, 2023 December 31, 2022 ($ in millions) Asset Liability Asset Liability Gross amounts recognized in the condensed consolidated balance sheet $ 465 $ 244 $ 433 $ 409 Gross amounts subject to offset in master netting arrangements not offset in the condensed consolidated balance sheet (180) (180) (220) (220) Cash collateral received/posted (102) — (66) (19) Net amounts $ 183 $ 64 $ 147 $ 170
Location and Amount of Pretax Gains and Losses of Derivatives	The table below provides information regarding the location and amount of pretax gains and losses of derivatives designated in fair value or cash flow hedging relationships: Three Months Ended June 30, Six Months Ended June 30, ($ in millions) 2023 2022 2023 2022 2023 2022 2023 2022 2023 2022 2023 2022 Financial Statement Caption in which Effects of Fair Value or Cash Flow Hedges are Recorded Sales Other (income) expense, net (1) Other comprehensive income (loss) Sales Other (income) expense, net (1) Other comprehensive income (loss) $ 15,035 $ 14,593 $ 172 $ 438 $ (17) $ 42 $ 29,522 $ 30,494 $ 259 $ 1,148 $ (132) $ 102 (Gain) loss on fair value hedging relationships: Interest rate swap contracts Hedged items — — — (4) — — — — — (14) — — Derivatives designated as hedging instruments — — — 1 — — — — — 4 — — Impact of cash flow hedging relationships: Foreign exchange contracts Amount of gain recognized in OCI on derivatives — — — — 194 403 — — — — 128 551 Increase in Sales as a result of AOCL reclassifications 24 172 — — (24) (172) 125 239 — — (125) (239) Interest rate contracts Amount of gain recognized in Other (income) expense, net on derivatives — — — — — — — — (1) (1) — — Amount of gain (loss) recognized in OCI on derivatives — — — — 13 — — — — — 13 (1) (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: Amount of Derivative Pretax (Gain) Loss Recognized in Income Three Months Ended June 30, Six Months Ended June 30, ($ in millions) 2023 2022 2023 2022 Derivatives Not Designated as Hedging Instruments Income Statement Caption Foreign exchange contracts (1) Other (income) expense, net $ (41) $ (64) $ (28) $ (36) Foreign exchange contracts (2) Sales (5) (36) (3) (38) (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. (2) These derivative contracts serve as economic hedges of forecasted transactions .
Information on Investments in Debt and Equity Securities	Information on investments in debt and equity securities is as follows: June 30, 2023 December 31, 2022 Amortized Gross Unrealized Fair Amortized Gross Unrealized Fair ($ in millions) Gains Losses Gains Losses Commercial paper $ 561 $ — $ — $ 561 $ 498 $ — $ — $ 498 U.S. government and agency securities 256 — — 256 68 — — 68 Corporate notes and bonds 4 — — 4 3 — — 3 Total debt securities $ 821 $ — $ — $ 821 $ 569 $ — $ — $ 569 Publicly traded equity securities (1) 1,520 1,284 Total debt and publicly traded equity securities $ 2,341 $ 1,853 (1) Unrealized net losses (gains) of $71 million and $(267) million were recorded in Other (income) expense, net in the second quarter and first six months of 2023, respectively, on equity securities still held at June 30, 2023. Unrealized net (gains) losses of $(25) million and $194 million were recorded in Other (income) expense, net in the second quarter and first six months of 2022, respectively, on equity securities still held at June 30, 2022.
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	Financial assets and liabilities measured at fair value on a recurring basis are summarized below: Fair Value Measurements Using Fair Value Measurements Using Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total ($ in millions) June 30, 2023 December 31, 2022 Assets Investments Commercial paper $ — $ 561 $ — $ 561 $ — $ 498 $ — $ 498 U.S. government and agency securities — 187 — 187 — — — — Publicly traded equity securities 1,184 — — 1,184 1,015 — — 1,015 1,184 748 — 1,932 1,015 498 — 1,513 Other assets (1) U.S. government and agency securities 69 — — 69 68 — — 68 Corporate notes and bonds 4 — — 4 3 — — 3 Publicly traded equity securities 336 — — 336 269 — — 269 409 — — 409 340 — — 340 Derivative assets (2) Forward exchange contracts — 316 — 316 — 218 — 218 Purchased currency options — 149 — 149 — 215 — 215 — 465 — 465 — 433 — 433 Total assets $ 1,593 $ 1,213 $ — $ 2,806 $ 1,355 $ 931 $ — $ 2,286 Liabilities Other liabilities Contingent consideration $ — $ — $ 349 $ 349 $ — $ — $ 456 $ 456 Derivative liabilities (2) Forward exchange contracts — 235 — 235 — 402 — 402 Written currency options — 9 — 9 — 7 — 7 — 244 — 244 — 409 — 409 Total liabilities $ — $ 244 $ 349 $ 593 $ — $ 409 $ 456 $ 865 (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 combinations is as follows: ($ in millions) 2023 2022 Fair value January 1 $ 456 $ 777 Changes in estimated fair value (1) 10 (114) Payments (117) (119) Other — (2) Fair value June 30 (2) $ 349 $ 542 (1) Recorded in Cost of sales, Research and development expenses, and Other (income) expense, net . Includes cumulative translation adjustments. (2) At June 30, 2023, $262 million 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 to present value the cash flows. Balance at June 30, 2023 includes $130 million recorded as a current liability for amounts expected to be paid within the next 12 months.

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 30, 2023
Inventory Disclosure [Abstract]
Inventories	Inventories consisted of: ($ in millions) June 30, 2023 December 31, 2022 Finished goods $ 1,841 $ 1,841 Raw materials and work in process 7,453 7,063 Supplies 269 238 Total 9,563 9,142 Decrease to LIFO cost (413) (293) $ 9,150 $ 8,849 Recognized as: Inventories $ 5,930 $ 5,911 Other Assets 3,220 2,938

Equity (Tables)

Equity (Tables)	6 Months Ended
	Jun. 30, 2023
Equity [Abstract]
Schedule of Equity	Three Months Ended June 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 April 1, 2022 3,577 $ 1,788 $ 44,275 $ 56,252 $ (4,369) 1,049 $ (57,063) $ 70 $ 40,953 Net income attributable to Merck & Co., Inc. — — — 3,944 — — — — 3,944 Other comprehensive income, net of taxes — — — — 42 — — — 42 Cash dividends declared on common stock ($0.69 per share) — — — (1,759) — — — — (1,759) Share-based compensation plans and other — — (160) — — (5) 293 — 133 Net income attributable to noncontrolling interests — — — — — — — 5 5 Balance at June 30, 2022 3,577 $ 1,788 $ 44,115 $ 58,437 $ (4,327) 1,044 $ (56,770) $ 75 $ 43,318 Balance at April 1, 2023 3,577 $ 1,788 $ 44,467 $ 62,039 $ (4,883) 1,040 $ (56,577) $ 71 $ 46,905 Net loss attributable to Merck & Co., Inc. — — — (5,975) — — — — (5,975) Other comprehensive loss, net of taxes — — — — (17) — — — (17) Cash dividends declared on common stock ($0.73 per share) — — — (1,866) — — — — (1,866) Treasury stock shares purchased — — — — — 3 (338) — (338) Share-based compensation plans and other — — (248) — — (5) 303 — 55 Net income attributable to noncontrolling interests — — — — — — — 3 3 Distributions attributable to noncontrolling interests — — — — — — — (25) (25) Balance at June 30, 2023 3,577 $ 1,788 $ 44,219 $ 54,198 $ (4,900) 1,038 $ (56,612) $ 49 $ 38,742 Six Months Ended June 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, 2022 3,577 $ 1,788 $ 44,238 $ 53,696 $ (4,429) 1,049 $ (57,109) $ 73 $ 38,257 Net income attributable to Merck & Co., Inc. — — — 8,254 — — — — 8,254 Other comprehensive income, net of taxes — — — — 102 — — — 102 Cash dividends declared on common stock ($1.38 per share) — — — (3,513) — — — — (3,513) Share-based compensation plans and other — — (123) — — (5) 339 — 216 Net income attributable to noncontrolling interests — — — — — — — 2 2 Balance at June 30, 2022 3,577 $ 1,788 $ 44,115 $ 58,437 $ (4,327) 1,044 $ (56,770) $ 75 $ 43,318 Balance at January 1, 2023 3,577 $ 1,788 $ 44,379 $ 61,081 $ (4,768) 1,039 $ (56,489) $ 67 $ 46,058 Net loss attributable to Merck & Co., Inc. — — — (3,154) — — — — (3,154) Other comprehensive loss, net of taxes — — — — (132) — — — (132) Cash dividends declared on common stock ($1.46 per share) — — — (3,729) — — — — (3,729) Treasury stock shares purchased — — — — — 4 (487) — (487) Share-based compensation plans and other — — (160) — — (5) 364 — 204 Net income attributable to noncontrolling interests — — — — — — — 7 7 Distributions attributable to noncontrolling interests — — — — — — — (25) (25) Balance at June 30, 2023 3,577 $ 1,788 $ 44,219 $ 54,198 $ (4,900) 1,038 $ (56,612) $ 49 $ 38,742

Pension and Other Postretirem_2

Pension and Other Postretirement Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2023
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 (credit) of such plans consisted of the following components: Three Months Ended Six Months Ended 2023 2022 2023 2022 ($ in millions) U.S. International U.S. International U.S. International U.S. International Service cost $ 76 $ 50 $ 99 $ 72 $ 152 $ 99 $ 198 $ 147 Interest cost 133 75 103 37 266 149 206 75 Expected return on plan assets (185) (130) (197) (98) (372) (257) (393) (199) Amortization of unrecognized prior service cost (credit) — 16 (8) (3) (1) 12 (16) (7) Net (gain) loss amortization — (1) 56 25 — (2) 112 50 Termination benefits 1 — 1 — 1 — 1 — Curtailments 2 — 4 — 5 — 8 — Settlements 5 — 101 — 26 — 101 — $ 32 $ 10 $ 159 $ 33 $ 77 $ 1 $ 217 $ 66
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 Six Months Ended ($ in millions) 2023 2022 2023 2022 Service cost $ 8 $ 12 $ 17 $ 25 Interest cost 16 11 31 23 Expected return on plan assets (16) (21) (32) (43) Amortization of unrecognized prior service credit (12) (14) (25) (29) Net gain amortization (11) (11) (21) (21) $ (15) $ (23) $ (30) $ (45)

Other (Income) Expense, Net (Ta

Other (Income) Expense, Net (Tables)	6 Months Ended
	Jun. 30, 2023
Other Income and Expenses [Abstract]
Other (Income) Expense, Net	Other (income) expense, net, consisted of: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Interest income $ (109) $ (15) $ (221) $ (22) Interest expense 277 240 519 483 Exchange losses 62 86 122 124 Loss (income) from investments in equity securities, net (1) 175 284 (274) 991 Net periodic defined benefit plan (credit) cost other than service cost (111) (27) (226) (148) Other, net (122) (130) 339 (280) $ 172 $ 438 $ 259 $ 1,148

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
Calculations of (Loss) Earnings Per Share	The calculations of (loss) earnings per share are as follows: Three Months Ended Six Months Ended ($ and shares in millions except per share amounts) 2023 2022 2023 2022 Net (Loss) Income Attributable to Merck & Co., Inc. $ (5,975) $ 3,944 $ (3,154) $ 8,254 Average common shares outstanding 2,539 2,531 2,539 2,529 Common shares issuable (1) — 9 — 9 Average common shares outstanding assuming dilution 2,539 2,540 2,539 2,538 Basic (Loss) Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders $ (2.35) $ 1.56 $ (1.24) $ 3.26 (Loss) Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders $ (2.35) $ 1.55 $ (1.24) $ 3.25 (1) Issuable primarily under share-based compensation plans.

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jun. 30, 2023
Equity [Abstract]
Changes in AOCI by Component	Changes in each component of other comprehensive income (loss) are as follows: Three Months Ended June 30, ($ in millions) Derivatives Employee Foreign Currency Accumulated Other Balance April 1, 2022, net of taxes $ 207 $ (2,711) $ (1,865) $ (4,369) Other comprehensive income (loss) before reclassification adjustments, pretax 403 168 (365) 206 Tax (85) (35) (22) (142) Other comprehensive income (loss) before reclassification adjustments, net of taxes 318 133 (387) 64 Reclassification adjustments, pretax (171) (1) 144 (2) — (27) Tax 36 (31) — 5 Reclassification adjustments, net of taxes (135) 113 — (22) Other comprehensive income (loss), net of taxes 183 246 (387) 42 Balance June 30, 2022, net of taxes $ 390 $ (2,465) $ (2,252) $ (4,327) Balance April 1, 2023, net of taxes $ (60) $ (2,458) $ (2,365) $ (4,883) Other comprehensive income (loss) before reclassification adjustments, pretax 194 (6) (115) 73 Tax (41) 1 (22) (62) Other comprehensive income (loss) before reclassification adjustments, net of taxes 153 (5) (137) 11 Reclassification adjustments, pretax (11) (1) (23) (2) — (34) Tax 3 3 — 6 Reclassification adjustments, net of taxes (8) (20) — (28) Other comprehensive income (loss), net of taxes 145 (25) (137) (17) Balance June 30, 2023, net of taxes $ 85 $ (2,483) $ (2,502) $ (4,900) Six Months Ended June 30, ($ in millions) Derivatives Employee Foreign Currency Accumulated Other Balance January 1, 2022, net of taxes $ 144 $ (2,743) $ (1,830) $ (4,429) Other comprehensive income (loss) before reclassification adjustments, pretax 551 169 (383) 337 Tax (116) (37) (39) (192) Other comprehensive income (loss) before reclassification adjustments, net of taxes 435 132 (422) 145 Reclassification adjustments, pretax (239) (1) 189 (2) — (50) Tax 50 (43) — 7 Reclassification adjustments, net of taxes (189) 146 — (43) Other comprehensive income (loss), net of taxes 246 278 (422) 102 Balance June 30, 2022, net of taxes $ 390 $ (2,465) $ (2,252) $ (4,327) Balance January 1, 2023, net of taxes $ 73 $ (2,408) $ (2,433) $ (4,768) Other comprehensive income (loss) before reclassification adjustments, pretax 128 (53) (36) 39 Tax (27) 3 (42) (66) Other comprehensive income (loss) before reclassification adjustments, net of taxes 101 (50) (78) (27) Reclassification adjustments, pretax (113) (1) (30) (2) 9 (134) Tax 24 5 — 29 Reclassification adjustments, net of taxes (89) (25) 9 (105) Other comprehensive income (loss), net of taxes 12 (75) (69) (132) Balance June 30, 2023, net of taxes $ 85 $ (2,483) $ (2,502) $ (4,900) (1) Primarily relates to foreign currency cash flow hedges that were reclassified from AOCL to Sales . (2) Includes net amortization of prior service cost, actuarial gains and losses, settlements and curtailments included in net periodic benefit cost (see Note 11)

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
	Jun. 30, 2023
Segment Reporting [Abstract]
Sales from Products	Sales of the Company’s products were as follows: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 ($ 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 $ 3,863 $ 2,408 $ 6,271 $ 3,197 $ 2,055 $ 5,252 $ 7,348 $ 4,718 $ 12,065 $ 5,976 $ 4,085 $ 10,061 Alliance revenue-Lynparza (1) 144 166 310 143 132 275 286 299 585 283 257 541 Alliance revenue-Lenvima (1) 163 79 242 128 103 231 316 158 474 284 175 459 Welireg 49 2 50 27 — 27 90 3 92 45 — 45 Alliance revenue-Reblozyl (2) 36 11 47 28 5 33 66 24 90 55 30 86 Vaccines Gardasil/Gardasil 9 464 1,994 2,458 428 1,245 1,674 880 3,550 4,430 846 2,287 3,133 ProQuad/M-M-R II /Varivax 447 135 582 434 143 578 868 242 1,109 805 243 1,047 RotaTeq 93 37 131 98 75 173 273 155 428 273 116 389 Vaxneuvance 147 20 168 11 — 12 241 33 274 16 1 16 Pneumovax 23 23 69 92 94 59 153 63 125 188 212 114 325 Vaqta 29 13 42 16 19 35 59 23 82 45 25 71 Hospital Acute Care Bridion 299 203 502 237 190 426 576 413 989 432 389 821 Prevymis 61 82 143 47 56 103 116 157 273 87 110 197 Dificid 68 8 76 63 3 66 130 11 141 113 6 119 Primaxin (2) 56 53 — 64 64 2 132 133 1 122 122 Noxafil 11 45 55 16 45 60 25 91 116 25 92 118 Zerbaxa 30 24 54 22 24 46 57 47 104 40 36 76 Cardiovascular Alliance revenue-Adempas/Verquvo (3) 70 (2) 68 88 10 98 153 14 167 159 11 170 Adempas — 65 65 — 63 63 — 125 125 — 124 124 Virology Lagevrio 2 201 203 — 1,177 1,177 — 595 595 1,523 2,901 4,424 Isentress/Isentress HD 56 80 136 67 80 147 108 151 259 128 177 305 Neuroscience Belsomra 21 42 63 19 50 69 37 82 119 39 98 137 Immunology Simponi — 180 180 — 181 181 — 359 359 — 366 366 Remicade — 48 48 — 53 53 — 99 99 — 114 114 Diabetes Januvia 243 267 511 301 455 756 514 548 1,062 626 909 1,535 Janumet 82 272 354 105 371 476 138 544 683 168 762 931 Other pharmaceutical (4) 171 382 553 157 372 528 342 793 1,138 317 814 1,131 Total Pharmaceutical segment sales 6,570 6,887 13,457 5,726 7,030 12,756 12,688 13,491 26,179 12,498 14,364 26,863 Animal Health: Livestock 165 643 807 164 662 826 338 1,318 1,656 335 1,322 1,658 Companion Animal 310 339 649 313 328 641 618 673 1,291 616 676 1,291 Total Animal Health segment sales 475 982 1,456 477 990 1,467 956 1,991 2,947 951 1,998 2,949 Total segment sales 7,045 7,869 14,913 6,203 8,020 14,223 13,644 15,482 29,126 13,449 16,362 29,812 Other (5) (27) 149 122 35 335 370 32 364 396 128 555 682 $ 7,018 $ 8,018 $ 15,035 $ 6,238 $ 8,355 $ 14,593 $ 13,676 $ 15,846 $ 29,522 $ 13,577 $ 16,917 $ 30,494 U.S. plus international may not equal total due to rounding. (1) Alliance revenue for Lynparza and Lenvima represents Merck’s share of profits, which are product sales net of cost of sales and commercialization costs (see Note 3). (2) Alliance revenue for Reblozyl represents royalties and, for the first six months of 2022, also includes the receipt of a regulatory approval milestone payment (see Note 3). (3) Alliance revenue for Adempas/Verquvo 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 3). (4) Other pharmaceutical primarily reflects sales of other human health pharmaceutical products, including products within the franchises not listed separately. (5) Other is primarily comprised of miscellaneous corporate revenue, including revenue hedging activities which increased sales by $128 million and $277 million for the six months ended June 30, 2023 and 2022, respectively, as well as revenue from third-party manufacturing arrangements (including sales to Organon). Other for the six months ended June 30, 2023 and 2022 also includes $54 million and $146 million, respectively, related to upfront and milestone payments received by Merck for out-licensing arrangements.
Consolidated Sales by Geographic Area	Consolidated sales by geographic area where derived are as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 United States $ 7,018 $ 6,238 $ 13,676 $ 13,577 Europe, Middle East and Africa 3,348 3,582 6,651 7,942 China 1,913 1,372 3,628 2,515 Asia Pacific (other than China and Japan) 848 1,008 1,694 1,938 Japan 675 1,114 1,434 2,103 Latin America 742 642 1,403 1,249 Other 491 637 1,036 1,170 $ 15,035 $ 14,593 $ 29,522 $ 30,494
Reconciliation of Segment Profits to Income before Taxes	A reconciliation of segment profits to (Loss) Income Before Taxes is as follows: Three Months Ended Six Months Ended ($ in millions) 2023 2022 2023 2022 Segment profits: Pharmaceutical segment $ 9,854 $ 9,173 $ 18,993 $ 18,673 Animal Health segment 467 571 1,032 1,156 Total segment profits 10,321 9,744 20,025 19,829 Other profits 19 260 184 454 Unallocated: Interest income 109 15 221 22 Interest expense (277) (240) (519) (483) Amortization (477) (463) (1,020) (1,163) Depreciation (376) (431) (775) (809) Research and development (13,194) (2,652) (17,341) (5,097) Restructuring costs (151) (142) (218) (194) Charge for Zetia antitrust litigation settlements — — (573) — Other unallocated, net (1,309) (1,604) (1,669) (3,211) $ (5,335) $ 4,487 $ (1,685) $ 9,348

Acquisitions, Research Collab_2

Acquisitions, Research Collaborations and License Agreements (Details) - USD ($) $ in Millions		1 Months Ended				3 Months Ended		6 Months Ended		14 Months Ended	20 Months Ended
	Jan. 31, 2023	Jun. 30, 2023	Feb. 28, 2023	Jan. 31, 2023	May 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Dec. 31, 2023
Business Acquisition [Line Items]
Research and development						$ 13,321	$ 2,798	$ 17,597	$ 5,374
Prometheus Biosciences, Inc.
Business Acquisition [Line Items]
Consideration transferred, asset acquisition		$ 11,000
Consideration transferred, to settle share-based equity awards		1,200
Consideration transferred, to settle equity awards, unvested		700
Net assets acquired		877
Cash recorded for asset acquisition		368
Investments recorded for asset acquisition		296
Deferred tax assets recorded for asset acquisition		218
Other net liabilities recorded for asset acquisition		$ 5
Research and development						$ 10,200		10,200
Imago Bio Sciences, Inc.
Business Acquisition [Line Items]
Consideration transferred, asset acquisition				$ 1,350
Net assets acquired	$ 219
Research and development								$ 1,200
Asset acquisition costs				60
Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Business Acquisition [Line Items]
Upfront and milestone payments made to collaborative partner			$ 175				$ 30		$ 30
Eligible future contingent development-related payments (up to)			1,000
Eligible future contingent regulatory milestone payments (up to)			2,800
Eligible future contingent sales-based milestone payments (up to)			$ 5,500
Preferred stock investment in counterparty	$ 100			$ 100
Milestone payments to be made to a collaborative partner					$ 30
Milestone payment to be made to a collaborative partner					25
Research and development payments made to a collaborative partner										$ 81
Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Development Milestones
Business Acquisition [Line Items]
Eligible future contingent development-related payments (up to)					90
Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | First Commercial Sale Milestones
Business Acquisition [Line Items]
Eligible future contingent sales-based milestone payments (up to)					290
Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Sales-Based Milestones
Business Acquisition [Line Items]
Eligible future contingent sales-based milestone payments (up to)					$ 780
Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Forecast
Business Acquisition [Line Items]
Research and development payments to be made to a collaborative partner											$ 111

Collaborative Arrangements - Na

Collaborative Arrangements - Narrative (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amortization					$ 1,020	$ 1,163
Sales	$ 15,035		$ 14,593		29,522	30,494
Operating Segments
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	14,913		14,223		29,126	29,812
Operating Segments | Pharmaceutical
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	13,457		12,756		26,179	26,863
Lynparza
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amortization						250
Lynparza | Other Noncurrent Assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Finite-lived intangible assets	1,700				1,700
Lenvima
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amortization					72
Lenvima | Operating Segments | Pharmaceutical
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	242		231		474	459
Lenvima | Other Noncurrent Assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Finite-lived intangible assets	756				756
Verquvo | Other Intangible Assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Finite-lived intangible assets	55				55
Adempas | Operating Segments | Pharmaceutical
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	65		63		125	124
Adempas | Other Intangible Assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Finite-lived intangible assets	586				586
Alliance Revenue - Reblozyl | Operating Segments | Pharmaceutical
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	47		$ 33		90	86
AstraZeneca | Sales-Based Milestones | Lynparza
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Probable contingent payments				$ 600
Liabilities				$ 600
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Lynparza
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales-based milestone payments						400
Potential future sales-based milestone payments	2,100				2,100
Capitalized milestone payment	245	$ 105				175	$ 250
Potential future regulatory milestone payments	850				850
Eisai | Sales-Based Milestones | Lenvima
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Probable contingent payments		125
Liabilities		$ 125
Eisai | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Lenvima
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales-based milestone payments						600
Potential future sales-based milestone payments	$ 2,400				$ 2,400
Capitalized milestone payment						25	$ 50
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales-based milestone payments						400
Bristol Myers Squibb Company | Licensing Agreements
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty rate, deduction					0.50
Bristol Myers Squibb Company | Licensing Agreements | Sales-Based Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contingent proceeds collaborative arrangement					$ 80
Bristol Myers Squibb Company | Licensing Agreements | Regulatory Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Proceeds from collaborators						$ 20
Bristol Myers Squibb Company | Licensing Agreements | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty rate					20%
Bristol Myers Squibb Company | Licensing Agreements | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty rate					24%

Collaborative Arrangements - Fi

Collaborative Arrangements - Financial Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	$ 15,035	$ 14,593	$ 29,522	$ 30,494
Cost of sales	4,024	4,216	7,951	9,596
Selling, general and administrative	2,702	2,512	5,182	4,834
Research and development	13,321	2,798	17,597	5,374
Payables included in Accrued and other liabilities	23,394		23,394		$ 24,239
Amortization			1,020	1,163
Alliance revenue - Lenvima
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amortization			72
Other current assets | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	332		332		303
Other current assets | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	242		242		214
Other current assets | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	144		144		143
Other current assets | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivables included in Other current assets	51		51		0
Accounts Payable and Accrued Liabilities | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Accrued and other liabilities	260		260		123
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	82		82		80
Accounts Payable and Accrued Liabilities | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Accrued and other liabilities	30		30		348
Other Noncurrent Liabilities | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payables included in Other Noncurrent Liabilities	600		600		$ 600
Revenue | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	335	299	633	574
Revenue | AstraZeneca | Collaborative Arrangement | Alliance revenue - Lynparza
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	310	275	585	541
Revenue | AstraZeneca | Collaborative Arrangement | Alliance revenue - Koselugo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	25	24	48	33
Revenue | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	242	231	474	459
Revenue | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Alliance revenue - profit sharing	68	98	167	170
Sales	142	167	308	303
Revenue | Bayer AG | Collaborative Arrangement | Adempas
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net sales by Merck	65	63	125	124
Revenue | Bayer AG | Collaborative Arrangement | Verquvo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net sales by Merck	9	6	16	9
Revenue | Ridgeback Biotherapeutics LP | Collaborative Arrangement | Lagevrio
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales	203	1,177	595	4,424
Cost of sales | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	78	62	148	361
Amortization of intangible assets				250
Cost of sales | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	57	53	183	106
Cost of sales | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	56	54	113	103
Cost of sales | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of sales	193	615	414	2,341
Selling, general and administrative | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	51	46	98	90
Selling, general and administrative | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	48	42	99	73
Selling, general and administrative | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	34	42	67	65
Selling, general and administrative | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Selling, general and administrative	24	34	51	69
Research and development | AstraZeneca | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	22	25	43	51
Research and development | Eisai | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	17	47	56	104
Research and development | Bayer AG | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	25	17	50	34
Research and development | Ridgeback Biotherapeutics LP | Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development	$ 10	$ 30	$ 26	$ 56

Spin-Off of Organon & Co. (Deta

Spin-Off of Organon & Co. (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Jun. 02, 2021	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales		$ 15,035	$ 14,593	$ 29,522	$ 30,494
Cost of sales		4,024	4,216	7,951	9,596
Other current assets		6,639		6,639		$ 7,169
Accrued and other current liabilities		13,747		13,747		14,159
Related Party
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other current assets		539		539		511
Accrued and other current liabilities		351		351		$ 345
Manufacturing and Supply Agreements | Related Party
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales		96	95	191	194
Cost of sales		$ 101	$ 103	$ 208	$ 208
Minimum | Transition Services Agreement | Related Party
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Period of continuing involvement after disposal	25 months
Minimum | Manufacturing and Supply Agreements | Related Party
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Period of continuing involvement after disposal	4 years
Maximum | Transition Services Agreement | Related Party
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Period of continuing involvement after disposal	35 months
Maximum | Manufacturing and Supply Agreements | Related Party
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Period of continuing involvement after disposal	10 years

Restructuring - Narrative (Deta

Restructuring - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2023
Restructuring Cost and Reserve [Line Items]
Expected restructuring and related cost	$ 3,900		$ 3,900
Estimate of cumulative pre tax costs that will result in cash outlays			70%
Estimate of cumulative pre tax costs that will be noncash			30%
Total pretax restructuring costs	236	$ 258	$ 333	$ 384
Cumulative costs since program inception	$ 3,700		$ 3,700
Forecast
Restructuring Cost and Reserve [Line Items]
Expected restructuring and related cost					$ 550

Restructuring - Charges Activit

Restructuring - Charges Activities by Type of Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	$ 236	$ 258	$ 333	$ 384
Separation Costs
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	110	106	151	132
Accelerated Depreciation
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	22	47	43	76
Other
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	104	105	139	176
Cost of sales
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	32	67	61	113
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	22	17	43	35
Cost of sales | Other
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	10	50	18	78
Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	52	27	53	48
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	0	8	0	12
Selling, general and administrative | Other
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	52	19	53	36
Research and development
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	1	22	1	29
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	0	22	0	29
Research and development | Other
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	1	0	1	0
Restructuring costs
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	151	142	218	194
Restructuring costs | Separation Costs
Restructuring Cost and Reserve [Line Items]
Total pretax restructuring costs	110	106	151	132
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	$ 41	$ 36	$ 67	$ 62

Restructuring - Activities by P

Restructuring - Activities by Program (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			$ 513
Expenses	$ 236	$ 258	333	$ 384
(Payments) receipts, net			(158)
Non-cash activity			(111)
Restructuring reserve, ending balance	577		577
Separation Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			479
Expenses	110	106	151	132
(Payments) receipts, net			(84)
Non-cash activity			0
Restructuring reserve, ending balance	546		546
Accelerated Depreciation
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			0
Expenses	22	47	43	76
(Payments) receipts, net			0
Non-cash activity			(43)
Restructuring reserve, ending balance	0		0
Other
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			34
Expenses	104	$ 105	139	$ 176
(Payments) receipts, net			(74)
Non-cash activity			(68)
Restructuring reserve, ending balance	$ 31		$ 31

Financial Instruments - Narrati

Financial Instruments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Derivative [Line Items]
Pretax net unrealized gains on derivatives maturing within next 12 months estimated to be reclassified from AOCI to sales			$ 83
Equity investments without readily determinable fair values	$ 949	$ 671	949	$ 671
Unrealized gains recognized on investments in equity securities without readily determinable fair value			3	20
Unrealized losses recognized on investments in equity securities without readily determinable fair values			23	1
Cumulative unrealized gains on investments	287		287
Cumulative unrealized losses on investments	42		42
Equity securities, noncurrent	622	805	622	805
(Income) loss from investments in equity securities, net	175	284	(274)	991
Fair value of loans payable and long-term debt, including current portion	34,000		34,000		$ 26,700
Debt, carrying amount	36,900		36,900		30,700
Factored accounts receivable			2,900		2,500
Restricted cash	44		44		67
Cash collateral received from counterparties	102		102		66
Cash collateral advanced to counterparties					19
Equity Funds
Derivative [Line Items]
(Income) loss from investments in equity securities, net	105	$ 302	(27)	$ 811
Level 2
Derivative [Line Items]
Cash equivalents	$ 4,900		$ 4,900		$ 11,300
Maximum | Derivatives Designated as Hedging Instruments
Derivative [Line Items]
Maximum average period of maturities of contracts in years (less than)			2 years
Maximum | Derivatives Not Designated as Hedging Instruments
Derivative [Line Items]
Maximum average period of maturities of contracts in years (less than)			6 months

Financial Instruments - Effect

Financial Instruments - Effect of Net Investment Hedges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Pretax (Gain) Loss Recognized in Other Comprehensive Income	$ 0	$ (31)	$ 1	$ (46)
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	0	(1)	1	(2)
Euro-denominated notes
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Pretax (Gain) Loss Recognized in Other Comprehensive Income	21	(128)	73	(181)
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 - Fair Va

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	Jun. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	$ 465	$ 433
Fair Value of Derivative, Liability	244	409
U.S Dollar Notional Amount	29,249	28,681
Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	243	247
Fair Value of Derivative, Liability	63	102
U.S Dollar Notional Amount	10,299	9,215
Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	222	186
Fair Value of Derivative, Liability	181	307
U.S Dollar Notional Amount	18,950	19,466
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other Assets
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	$ 43	$ 27
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
U.S Dollar Notional Amount	$ 1,750	$ 1,609
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Liability	$ 1	$ 1
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Noncurrent Liabilities	Other Noncurrent Liabilities
U.S Dollar Notional Amount	$ 328	$ 91
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other current assets
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	$ 200	$ 220
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other current assets	Other current assets
U.S Dollar Notional Amount	$ 5,976	$ 4,824
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Accrued and other current liabilities
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Liability	$ 62	$ 101
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Accrued and other current liabilities	Accrued and other current liabilities
U.S Dollar Notional Amount	$ 2,245	$ 2,691
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Fair Value of Derivative, Asset	222	186
Fair Value of Derivative, Liability	181	307
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments | Other current assets
Derivatives, Fair Value [Line Items]
U.S Dollar Notional Amount	8,838	8,540
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments | Accrued and other current liabilities
Derivatives, Fair Value [Line Items]
U.S Dollar Notional Amount	$ 10,112	$ 10,926

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 ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross amounts recognized in the consolidated balance sheet, asset	$ 465	$ 433
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, asset	(180)	(220)
Cash collateral received, asset	(102)	(66)
Net amounts, asset	183	147
Gross amounts recognized in the consolidated balance sheet, liability	244	409
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, liability	(180)	(220)
Cash collateral received, liability	0	(19)
Net amounts, liability	$ 64	$ 170

Financial Instruments - Locatio

Financial Instruments - Location and Amount of Pretax (Gains) Losses of Derivatives (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Derivative Instruments, Gain (Loss) [Line Items]
Sales	$ 15,035	$ 14,593	$ 29,522	$ 30,494
Other (income) expense, net	172	438	259	1,148
Other comprehensive income (loss)	(17)	42	(132)	102
Interest rate swap contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in OCI on derivatives	13	0	13	(1)
Amount of gain recognized in Other (income) expense, net on derivatives	0	0	(1)	(1)
Interest rate swap contracts | Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	0	(4)	0	(14)
Derivatives designated as hedging instruments	0	1	0	4
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in OCI on derivatives	194	403	128	551
Increase in Sales as a result of AOCL reclassifications	(24)	(172)	(125)	(239)
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	$ 24	$ 172	$ 125	$ 239

Financial Instruments - Income

Financial Instruments - Income Statement Effects on Derivatives Not Designated as Hedging Instruments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Currency Swap | Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Derivative Pretax (Gain) Loss Recognized in Income	$ (41)	$ (64)	$ (28)	$ (36)
Foreign Exchange Future | Sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Derivative Pretax (Gain) Loss Recognized in Income	$ (5)	$ (36)	$ (3)	$ (38)

Financial Instruments - Infor_2

Financial Instruments - Information on Available-for-sale Investments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	$ 821		$ 821		$ 569
Debt securities, unrealized gains	0		0		0
Debt securities, unrealized losses	0		0		0
Debt securities, fair value	821		821		569
Publicly traded equity securities, fair value	1,520		1,520		1,284
Total debt and publicly traded equity securities, fair value	2,341		2,341		1,853
Unrealized net (gains) losses	71	$ (25)	(267)	$ 194
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	561		561		498
Debt securities, unrealized gains	0		0		0
Debt securities, unrealized losses	0		0		0
Debt securities, fair value	561		561		498
U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	256		256		68
Debt securities, unrealized gains	0		0		0
Debt securities, unrealized losses	0		0		0
Debt securities, fair value	256		256		68
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	4		4		3
Debt securities, unrealized gains	0		0		0
Debt securities, unrealized losses	0		0		0
Debt securities, fair value	$ 4		$ 4		$ 3

Financial Instruments - Financi

Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Assets
Investments	$ 821	$ 569
Publicly traded equity securities	1,520	1,284
Derivative assets	465	433
Liabilities
Contingent consideration	349	456	$ 542	$ 777
Derivative liabilities	244	409
Commercial paper
Assets
Investments	561	498
U.S. government and agency securities
Assets
Investments	256	68
Corporate notes and bonds
Assets
Investments	4	3
Fair Value, Measurements, Recurring
Assets
Investments	1,932	1,513
Other assets	409	340
Derivative assets	465	433
Total assets	2,806	2,286
Liabilities
Contingent consideration	349	456
Derivative liabilities	244	409
Total liabilities	593	865
Fair Value, Measurements, Recurring | Foreign exchange contracts
Assets
Derivative assets	316	218
Liabilities
Derivative liabilities	235	402
Fair Value, Measurements, Recurring | Currency options
Assets
Derivative assets	149	215
Liabilities
Derivative liabilities	9	7
Fair Value, Measurements, Recurring | Level 1
Assets
Investments	1,184	1,015
Other assets	409	340
Derivative assets	0	0
Total assets	1,593	1,355
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 | Currency options
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Level 2
Assets
Investments	748	498
Other assets	0	0
Derivative assets	465	433
Total assets	1,213	931
Liabilities
Contingent consideration	0	0
Derivative liabilities	244	409
Total liabilities	244	409
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts
Assets
Derivative assets	316	218
Liabilities
Derivative liabilities	235	402
Fair Value, Measurements, Recurring | Level 2 | Currency options
Assets
Derivative assets	149	215
Liabilities
Derivative liabilities	9	7
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	349	456
Derivative liabilities	0	0
Total liabilities	349	456
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 | Currency options
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Commercial paper
Assets
Investments	561	498
Fair Value, Measurements, Recurring | Commercial paper | Level 1
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Commercial paper | Level 2
Assets
Investments	561	498
Fair Value, Measurements, Recurring | Commercial paper | Level 3
Assets
Investments	0	0
Fair Value, Measurements, Recurring | U.S. government and agency securities
Assets
Investments	187	0
Other assets	69	68
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 1
Assets
Investments	0	0
Other assets	69	68
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 2
Assets
Investments	187	0
Other assets	0	0
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 3
Assets
Investments	0	0
Other assets	0	0
Fair Value, Measurements, Recurring | Corporate notes and bonds
Assets
Other assets	4	3
Fair Value, Measurements, Recurring | Corporate notes and bonds | Level 1
Assets
Other assets	4	3
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
Fair Value, Measurements, Recurring | Publicly traded equity securities
Assets
Publicly traded equity securities	1,184	1,015
Other assets	336	269
Fair Value, Measurements, Recurring | Publicly traded equity securities | Level 1
Assets
Publicly traded equity securities	1,184	1,015
Other assets	336	269
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

Financial Instruments - Infor_3

Financial Instruments - Information About Changes in Liabilities for Contingent Consideration (Details) $ in Millions	6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning balance	$ 456	$ 777
Changes in estimated fair value	10	(114)
Payments	(117)	(119)
Other	0	(2)
Fair value, ending balance	349	542
Contingent consideration	349	$ 542
Current liability	130
Sanofi Pasteur
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, ending balance	262
Contingent consideration	$ 262
Contingent consideration, measurement input, discount rate	0.115

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Finished goods	$ 1,841	$ 1,841
Raw materials and work in process	7,453	7,063
Supplies	269	238
Total	9,563	9,142
Decrease to LIFO cost	(413)	(293)
Total current and noncurrent inventories	9,150	8,849
Recognized as:
Inventories	5,930	5,911
Other Assets	$ 3,220	$ 2,938

Inventories - Narrative (Detail

Inventories - Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Inventory [Line Items]
Inventories classified in Other assets	$ 3,220	$ 2,938
Inventories Not Expected to be Sold Within One Year
Inventory [Line Items]
Inventories classified in Other assets	2,600	2,400
Inventories Produced in Preparation for Product Launches
Inventory [Line Items]
Inventories classified in Other assets	$ 663	$ 516

Long-Term Debt (Details)

Long-Term Debt (Details) - Senior Notes	1 Months Ended
	May 31, 2023 USD ($)
Debt Instrument [Line Items]
Face amount of debt	$ 6,000,000,000
Proceeds from issuance of debt	5,900,000,000
4.05% Notes due 2028
Debt Instrument [Line Items]
Face amount of debt	$ 500,000,000
Stated interest rate	4.05%
4.30% notes due 2030
Debt Instrument [Line Items]
Face amount of debt	$ 750,000,000
Stated interest rate	4.30%
4.50% Notes Due 2033
Debt Instrument [Line Items]
Face amount of debt	$ 1,500,000,000
Stated interest rate	4.50%
4.90% Notes Due 2044
Debt Instrument [Line Items]
Face amount of debt	$ 750,000,000
Stated interest rate	4.90%
5.00% Notes Due 2053
Debt Instrument [Line Items]
Face amount of debt	$ 1,500,000,000
Stated interest rate	5%
5.15% Notes Due 2063
Debt Instrument [Line Items]
Face amount of debt	$ 1,000,000,000
Stated interest rate	5.15%

Contingencies (Details)

Contingencies (Details) $ in Millions			6 Months Ended
	Apr. 13, 2023 patent	Dec. 19, 2022	Jun. 30, 2023 USD ($) company case Plaintiff	Jul. 27, 2023 motion_for_summary_judgment	Dec. 31, 2022 USD ($)
Commercial and Other Litigation
Loss Contingencies [Line Items]
Loss contingency, pending claims | case			2
Loss contingency, number of plaintiffs | Plaintiff			2
Commercial and Other Litigation | Subsequent Event
Loss Contingencies [Line Items]
Loss contingency, number of motion for summary judgments | motion_for_summary_judgment				2
Legal Defense Costs
Loss Contingencies [Line Items]
Legal defense costs reserve | $			$ 225		$ 230
Zetia antitrust litigation
Loss Contingencies [Line Items]
Loss related to litigation settlement | $			$ 572.5
Complaint Against The Johns Hopkins University | Pending Litigation
Loss Contingencies [Line Items]
Loss contingency, number of patents allegedly infringed | patent	5
Gardasil/Gardasil 9 | U.S.
Loss Contingencies [Line Items]
Loss contingency, pending claims | case			95
Gardasil/Gardasil 9 | Non-US
Loss Contingencies [Line Items]
Loss contingency, pending claims | case			15
Bridion | Patents
Loss Contingencies [Line Items]
Loss contingency, claims settled | company			5
Bridion | Patents | Pending Litigation
Loss Contingencies [Line Items]
Loss contingency, pending claims | company			2
Loss contingency, trial period		1 day
Januvia and Janumet | Patents
Loss Contingencies [Line Items]
Loss contingency, claims settled | company			25

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, beginning balance (in shares)			3,577,103,522
Treasury stock, beginning balance (in shares)			1,039,269,638
Equity, beginning balance	$ 46,905	$ 40,953	$ 46,058	$ 38,257
Net (loss) income attributable to Merck & Co., Inc.	(5,975)	3,944	(3,154)	8,254
Other comprehensive income (loss), net of taxes	(17)	42	(132)	102
Cash dividends declared on common stock	(1,866)	(1,759)	(3,729)	(3,513)
Treasury stock shares purchased	(338)		(487)
Share-based compensation plans and other	55	133	204	216
Net income attributable to noncontrolling interests	3	5	7	2
Distributions attributable to noncontrolling interests	$ (25)		$ (25)
Common stock, ending balance (in shares)	3,577,103,522		3,577,103,522
Treasury stock, ending balance (in shares)	1,037,678,033		1,037,678,033
Equity, ending balance	$ 38,742	$ 43,318	$ 38,742	$ 43,318
Cash dividends declared on common stock (in dollars per share)	$ 0.73	$ 0.69	$ 1.46	$ 1.38
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, 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
Common stock, 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	44,467	44,275	44,379	44,238
Share-based compensation plans and other	(248)	(160)	(160)	(123)
Equity, ending balance	44,219	44,115	44,219	44,115
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity, beginning balance	62,039	56,252	61,081	53,696
Net (loss) income attributable to Merck & Co., Inc.	(5,975)	3,944	(3,154)	8,254
Cash dividends declared on common stock	(1,866)	(1,759)	(3,729)	(3,513)
Equity, ending balance	54,198	58,437	54,198	58,437
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity, beginning balance	(4,883)	(4,369)	(4,768)	(4,429)
Other comprehensive income (loss), net of taxes	(17)	42	(132)	102
Equity, ending balance	$ (4,900)	$ (4,327)	$ (4,900)	$ (4,327)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock, beginning balance (in shares)	1,040,000,000	1,049,000,000	1,039,000,000	1,049,000,000
Equity, beginning balance	$ (56,577)	$ (57,063)	$ (56,489)	$ (57,109)
Treasury stock shares purchased (in shares)	3,000,000		4,000,000
Treasury stock shares purchased	$ (338)		$ (487)
Share-based compensation plans and other (in shares)	(5,000,000)	(5,000,000)	(5,000,000)	(5,000,000)
Share-based compensation plans and other	$ 303	$ 293	$ 364	$ 339
Treasury stock, ending balance (in shares)	1,038,000,000	1,044,000,000	1,038,000,000	1,044,000,000
Equity, ending balance	$ (56,612)	$ (56,770)	$ (56,612)	$ (56,770)
Non- controlling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity, beginning balance	71	70	67	73
Net income attributable to noncontrolling interests	3	5	7	2
Distributions attributable to noncontrolling interests	(25)		(25)
Equity, ending balance	$ 49	$ 75	$ 49	$ 75

Pension and Other Postretirem_3

Pension and Other Postretirement Benefit Plans - Net Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 8	$ 12	$ 17	$ 25
Interest cost	16	11	31	23
Expected return on plan assets	(16)	(21)	(32)	(43)
Amortization of unrecognized prior service cost (credit)	(12)	(14)	(25)	(29)
Net (gain) loss amortization	(11)	(11)	(21)	(21)
Net periodic benefit cost	(15)	(23)	(30)	(45)
U.S. | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	76	99	152	198
Interest cost	133	103	266	206
Expected return on plan assets	(185)	(197)	(372)	(393)
Amortization of unrecognized prior service cost (credit)	0	(8)	(1)	(16)
Net (gain) loss amortization	0	56	0	112
Termination benefits	1	1	1	1
Curtailments	2	4	5	8
Settlements	5	101	26	101
Net periodic benefit cost	32	159	77	217
International | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	50	72	99	147
Interest cost	75	37	149	75
Expected return on plan assets	(130)	(98)	(257)	(199)
Amortization of unrecognized prior service cost (credit)	16	(3)	12	(7)
Net (gain) loss amortization	(1)	25	(2)	50
Termination benefits	0	0	0	0
Curtailments	0	0	0	0
Settlements	0	0	0	0
Net periodic benefit cost	$ 10	$ 33	$ 1	$ 66

Pension and Other Postretirem_4

Pension and Other Postretirement Benefit Plans - Narrative (Details) $ in Millions	6 Months Ended
	Jun. 30, 2023 USD ($)
Retirement Benefits [Abstract]
Increase to pension liabilities due to remeasurement	$ 47

Other (Income) Expense, Net - S

Other (Income) Expense, Net - Schedule of Other (Income) Expense, Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Other Income and Expenses [Abstract]
Interest income	$ (109)	$ (15)	$ (221)	$ (22)
Interest expense	277	240	519	483
Exchange losses	62	86	122	124
Loss (income) from investments in equity securities, net	175	284	(274)	991
Net periodic defined benefit plan (credit) cost other than service cost	(111)	(27)	(226)	(148)
Other, net	(122)	(130)	339	(280)
Other (income) expense, net	$ 172	$ 438	$ 259	$ 1,148

Other (Income) Expense, Net - N

Other (Income) Expense, Net - Narrative (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Loss Contingencies [Line Items]
Interest paid	$ 449	$ 449
Zetia antitrust litigation
Loss Contingencies [Line Items]
Loss related to litigation settlement	$ 572.5

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Income tax provision	$ 637,000,000	$ 538,000,000	$ 1,462,000,000	$ 1,092,000,000
Effective income tax rate	(11.90%)	12%	(86.80%)	11.70%
Tax benefit resulting from acquisition charge	$ 0		$ 0
Effective income tax rate, unfavorable impact	25.10%		101.90%

Earnings Per Share - Calculatio

Earnings Per Share - Calculations of (Loss) Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Earnings Per Share [Abstract]
Net (loss) income attributable to Merck & Co., Inc., basic	$ (5,975)	$ 3,944	$ (3,154)	$ 8,254
Net (loss) income attributable to Merck & Co., Inc., diluted	$ (5,975)	$ 3,944	$ (3,154)	$ 8,254
Average common shares outstanding (in shares)	2,539	2,531	2,539	2,529
Common shares issuable (in shares)	0	9	0	9
Average common shares outstanding assuming dilution (in shares)	2,539	2,540	2,539	2,538
Basic (Loss) Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share)	$ (2.35)	$ 1.56	$ (1.24)	$ 3.26
(Loss) Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share)	$ (2.35)	$ 1.55	$ (1.24)	$ 3.25

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Earnings Per Share [Abstract]
Antidilutive shares (in shares)	0	2	0	6

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Equity, beginning balance	$ 46,905	$ 40,953	$ 46,058	$ 38,257
Other comprehensive income (loss) before reclassification adjustments, pretax	73	206	39	337
Tax	(62)	(142)	(66)	(192)
Other comprehensive income (loss) before reclassification adjustments, net of taxes	11	64	(27)	145
Reclassification adjustments, pretax	(34)	(27)	(134)	(50)
Tax	6	5	29	7
Reclassification adjustments, net of taxes	(28)	(22)	(105)	(43)
Other comprehensive income (loss), net of taxes	(17)	42	(132)	102
Equity, ending balance	38,742	43,318	38,742	43,318
Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Equity, beginning balance	(60)	207	73	144
Other comprehensive income (loss) before reclassification adjustments, pretax	194	403	128	551
Tax	(41)	(85)	(27)	(116)
Other comprehensive income (loss) before reclassification adjustments, net of taxes	153	318	101	435
Reclassification adjustments, pretax	(11)	(171)	(113)	(239)
Tax	3	36	24	50
Reclassification adjustments, net of taxes	(8)	(135)	(89)	(189)
Other comprehensive income (loss), net of taxes	145	183	12	246
Equity, ending balance	85	390	85	390
Employee Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Equity, beginning balance	(2,458)	(2,711)	(2,408)	(2,743)
Other comprehensive income (loss) before reclassification adjustments, pretax	(6)	168	(53)	169
Tax	1	(35)	3	(37)
Other comprehensive income (loss) before reclassification adjustments, net of taxes	(5)	133	(50)	132
Reclassification adjustments, pretax	(23)	144	(30)	189
Tax	3	(31)	5	(43)
Reclassification adjustments, net of taxes	(20)	113	(25)	146
Other comprehensive income (loss), net of taxes	(25)	246	(75)	278
Equity, ending balance	(2,483)	(2,465)	(2,483)	(2,465)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Equity, beginning balance	(2,365)	(1,865)	(2,433)	(1,830)
Other comprehensive income (loss) before reclassification adjustments, pretax	(115)	(365)	(36)	(383)
Tax	(22)	(22)	(42)	(39)
Other comprehensive income (loss) before reclassification adjustments, net of taxes	(137)	(387)	(78)	(422)
Reclassification adjustments, pretax	0	0	9	0
Tax	0	0	0	0
Reclassification adjustments, net of taxes	0	0	9	0
Other comprehensive income (loss), net of taxes	(137)	(387)	(69)	(422)
Equity, ending balance	(2,502)	(2,252)	(2,502)	(2,252)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Equity, beginning balance	(4,883)	(4,369)	(4,768)	(4,429)
Equity, ending balance	$ (4,900)	$ (4,327)	$ (4,900)	$ (4,327)

Segment Reporting - Narrative (

Segment Reporting - Narrative (Details) $ in Billions	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) segment	Jun. 30, 2022 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment			2
Sales discounts | $	$ 3.2	$ 3	$ 6.3	$ 5.9

Segment Reporting - Sales from

Segment Reporting - Sales from Products (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Sales	$ 15,035	$ 14,593	$ 29,522	$ 30,494
Increase in hedge revenue			128	277
Revenue related to the sale of the marketing rights			54	146
U.S.
Segment Reporting Information [Line Items]
Sales	7,018	6,238	13,676	13,577
Int’l
Segment Reporting Information [Line Items]
Sales	8,018	8,355	15,846	16,917
Operating Segments
Segment Reporting Information [Line Items]
Sales	14,913	14,223	29,126	29,812
Operating Segments | U.S.
Segment Reporting Information [Line Items]
Sales	7,045	6,203	13,644	13,449
Operating Segments | Int’l
Segment Reporting Information [Line Items]
Sales	7,869	8,020	15,482	16,362
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Sales	122	370	396	682
Corporate, Non-Segment | U.S.
Segment Reporting Information [Line Items]
Sales	(27)	35	32	128
Corporate, Non-Segment | Int’l
Segment Reporting Information [Line Items]
Sales	149	335	364	555
Pharmaceutical | Operating Segments
Segment Reporting Information [Line Items]
Sales	13,457	12,756	26,179	26,863
Pharmaceutical | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Sales	6,570	5,726	12,688	12,498
Pharmaceutical | Operating Segments | Int’l
Segment Reporting Information [Line Items]
Sales	6,887	7,030	13,491	14,364
Pharmaceutical | Operating Segments | Keytruda
Segment Reporting Information [Line Items]
Sales	6,271	5,252	12,065	10,061
Pharmaceutical | Operating Segments | Keytruda | U.S.
Segment Reporting Information [Line Items]
Sales	3,863	3,197	7,348	5,976
Pharmaceutical | Operating Segments | Keytruda | Int’l
Segment Reporting Information [Line Items]
Sales	2,408	2,055	4,718	4,085
Pharmaceutical | Operating Segments | Alliance revenue - Lynparza
Segment Reporting Information [Line Items]
Sales	310	275	585	541
Pharmaceutical | Operating Segments | Alliance revenue - Lynparza | U.S.
Segment Reporting Information [Line Items]
Sales	144	143	286	283
Pharmaceutical | Operating Segments | Alliance revenue - Lynparza | Int’l
Segment Reporting Information [Line Items]
Sales	166	132	299	257
Pharmaceutical | Operating Segments | Alliance revenue - Lenvima
Segment Reporting Information [Line Items]
Sales	242	231	474	459
Pharmaceutical | Operating Segments | Alliance revenue - Lenvima | U.S.
Segment Reporting Information [Line Items]
Sales	163	128	316	284
Pharmaceutical | Operating Segments | Alliance revenue - Lenvima | Int’l
Segment Reporting Information [Line Items]
Sales	79	103	158	175
Pharmaceutical | Operating Segments | Welireg
Segment Reporting Information [Line Items]
Sales	50	27	92	45
Pharmaceutical | Operating Segments | Welireg | U.S.
Segment Reporting Information [Line Items]
Sales	49	27	90	45
Pharmaceutical | Operating Segments | Welireg | Int’l
Segment Reporting Information [Line Items]
Sales	2	0	3	0
Pharmaceutical | Operating Segments | Alliance Revenue - Reblozyl
Segment Reporting Information [Line Items]
Sales	47	33	90	86
Pharmaceutical | Operating Segments | Alliance Revenue - Reblozyl | U.S.
Segment Reporting Information [Line Items]
Sales	36	28	66	55
Pharmaceutical | Operating Segments | Alliance Revenue - Reblozyl | Int’l
Segment Reporting Information [Line Items]
Sales	11	5	24	30
Pharmaceutical | Operating Segments | Gardasil/Gardasil 9
Segment Reporting Information [Line Items]
Sales	2,458	1,674	4,430	3,133
Pharmaceutical | Operating Segments | Gardasil/Gardasil 9 | U.S.
Segment Reporting Information [Line Items]
Sales	464	428	880	846
Pharmaceutical | Operating Segments | Gardasil/Gardasil 9 | Int’l
Segment Reporting Information [Line Items]
Sales	1,994	1,245	3,550	2,287
Pharmaceutical | Operating Segments | ProQuad/M-M-R II/Varivax
Segment Reporting Information [Line Items]
Sales	582	578	1,109	1,047
Pharmaceutical | Operating Segments | ProQuad/M-M-R II/Varivax | U.S.
Segment Reporting Information [Line Items]
Sales	447	434	868	805
Pharmaceutical | Operating Segments | ProQuad/M-M-R II/Varivax | Int’l
Segment Reporting Information [Line Items]
Sales	135	143	242	243
Pharmaceutical | Operating Segments | RotaTeq
Segment Reporting Information [Line Items]
Sales	131	173	428	389
Pharmaceutical | Operating Segments | RotaTeq | U.S.
Segment Reporting Information [Line Items]
Sales	93	98	273	273
Pharmaceutical | Operating Segments | RotaTeq | Int’l
Segment Reporting Information [Line Items]
Sales	37	75	155	116
Pharmaceutical | Operating Segments | Vaxneuvance
Segment Reporting Information [Line Items]
Sales	168	12	274	16
Pharmaceutical | Operating Segments | Vaxneuvance | U.S.
Segment Reporting Information [Line Items]
Sales	147	11	241	16
Pharmaceutical | Operating Segments | Vaxneuvance | Int’l
Segment Reporting Information [Line Items]
Sales	20	0	33	1
Pharmaceutical | Operating Segments | Pneumovax 23
Segment Reporting Information [Line Items]
Sales	92	153	188	325
Pharmaceutical | Operating Segments | Pneumovax 23 | U.S.
Segment Reporting Information [Line Items]
Sales	23	94	63	212
Pharmaceutical | Operating Segments | Pneumovax 23 | Int’l
Segment Reporting Information [Line Items]
Sales	69	59	125	114
Pharmaceutical | Operating Segments | Vaqta
Segment Reporting Information [Line Items]
Sales	42	35	82	71
Pharmaceutical | Operating Segments | Vaqta | U.S.
Segment Reporting Information [Line Items]
Sales	29	16	59	45
Pharmaceutical | Operating Segments | Vaqta | Int’l
Segment Reporting Information [Line Items]
Sales	13	19	23	25
Pharmaceutical | Operating Segments | Bridion
Segment Reporting Information [Line Items]
Sales	502	426	989	821
Pharmaceutical | Operating Segments | Bridion | U.S.
Segment Reporting Information [Line Items]
Sales	299	237	576	432
Pharmaceutical | Operating Segments | Bridion | Int’l
Segment Reporting Information [Line Items]
Sales	203	190	413	389
Pharmaceutical | Operating Segments | Prevymis
Segment Reporting Information [Line Items]
Sales	143	103	273	197
Pharmaceutical | Operating Segments | Prevymis | U.S.
Segment Reporting Information [Line Items]
Sales	61	47	116	87
Pharmaceutical | Operating Segments | Prevymis | Int’l
Segment Reporting Information [Line Items]
Sales	82	56	157	110
Pharmaceutical | Operating Segments | Dificid
Segment Reporting Information [Line Items]
Sales	76	66	141	119
Pharmaceutical | Operating Segments | Dificid | U.S.
Segment Reporting Information [Line Items]
Sales	68	63	130	113
Pharmaceutical | Operating Segments | Dificid | Int’l
Segment Reporting Information [Line Items]
Sales	8	3	11	6
Pharmaceutical | Operating Segments | Primaxin
Segment Reporting Information [Line Items]
Sales	53	64	133	122
Pharmaceutical | Operating Segments | Primaxin | U.S.
Segment Reporting Information [Line Items]
Sales	(2)	0	2	1
Pharmaceutical | Operating Segments | Primaxin | Int’l
Segment Reporting Information [Line Items]
Sales	56	64	132	122
Pharmaceutical | Operating Segments | Noxafil
Segment Reporting Information [Line Items]
Sales	55	60	116	118
Pharmaceutical | Operating Segments | Noxafil | U.S.
Segment Reporting Information [Line Items]
Sales	11	16	25	25
Pharmaceutical | Operating Segments | Noxafil | Int’l
Segment Reporting Information [Line Items]
Sales	45	45	91	92
Pharmaceutical | Operating Segments | Zerbaxa
Segment Reporting Information [Line Items]
Sales	54	46	104	76
Pharmaceutical | Operating Segments | Zerbaxa | U.S.
Segment Reporting Information [Line Items]
Sales	30	22	57	40
Pharmaceutical | Operating Segments | Zerbaxa | Int’l
Segment Reporting Information [Line Items]
Sales	24	24	47	36
Pharmaceutical | Operating Segments | Alliance revenue - Adempas/Verquvo
Segment Reporting Information [Line Items]
Sales	68	98	167	170
Pharmaceutical | Operating Segments | Alliance revenue - Adempas/Verquvo | U.S.
Segment Reporting Information [Line Items]
Sales	70	88	153	159
Pharmaceutical | Operating Segments | Alliance revenue - Adempas/Verquvo | Int’l
Segment Reporting Information [Line Items]
Sales	(2)	10	14	11
Pharmaceutical | Operating Segments | Adempas
Segment Reporting Information [Line Items]
Sales	65	63	125	124
Pharmaceutical | Operating Segments | Adempas | U.S.
Segment Reporting Information [Line Items]
Sales	0	0	0	0
Pharmaceutical | Operating Segments | Adempas | Int’l
Segment Reporting Information [Line Items]
Sales	65	63	125	124
Pharmaceutical | Operating Segments | Lagevrio
Segment Reporting Information [Line Items]
Sales	203	1,177	595	4,424
Pharmaceutical | Operating Segments | Lagevrio | U.S.
Segment Reporting Information [Line Items]
Sales	2	0	0	1,523
Pharmaceutical | Operating Segments | Lagevrio | Int’l
Segment Reporting Information [Line Items]
Sales	201	1,177	595	2,901
Pharmaceutical | Operating Segments | Isentress/Isentress HD
Segment Reporting Information [Line Items]
Sales	136	147	259	305
Pharmaceutical | Operating Segments | Isentress/Isentress HD | U.S.
Segment Reporting Information [Line Items]
Sales	56	67	108	128
Pharmaceutical | Operating Segments | Isentress/Isentress HD | Int’l
Segment Reporting Information [Line Items]
Sales	80	80	151	177
Pharmaceutical | Operating Segments | Belsomra
Segment Reporting Information [Line Items]
Sales	63	69	119	137
Pharmaceutical | Operating Segments | Belsomra | U.S.
Segment Reporting Information [Line Items]
Sales	21	19	37	39
Pharmaceutical | Operating Segments | Belsomra | Int’l
Segment Reporting Information [Line Items]
Sales	42	50	82	98
Pharmaceutical | Operating Segments | Simponi
Segment Reporting Information [Line Items]
Sales	180	181	359	366
Pharmaceutical | Operating Segments | Simponi | U.S.
Segment Reporting Information [Line Items]
Sales	0	0	0	0
Pharmaceutical | Operating Segments | Simponi | Int’l
Segment Reporting Information [Line Items]
Sales	180	181	359	366
Pharmaceutical | Operating Segments | Remicade
Segment Reporting Information [Line Items]
Sales	48	53	99	114
Pharmaceutical | Operating Segments | Remicade | U.S.
Segment Reporting Information [Line Items]
Sales	0	0	0	0
Pharmaceutical | Operating Segments | Remicade | Int’l
Segment Reporting Information [Line Items]
Sales	48	53	99	114
Pharmaceutical | Operating Segments | Januvia
Segment Reporting Information [Line Items]
Sales	511	756	1,062	1,535
Pharmaceutical | Operating Segments | Januvia | U.S.
Segment Reporting Information [Line Items]
Sales	243	301	514	626
Pharmaceutical | Operating Segments | Januvia | Int’l
Segment Reporting Information [Line Items]
Sales	267	455	548	909
Pharmaceutical | Operating Segments | Janumet
Segment Reporting Information [Line Items]
Sales	354	476	683	931
Pharmaceutical | Operating Segments | Janumet | U.S.
Segment Reporting Information [Line Items]
Sales	82	105	138	168
Pharmaceutical | Operating Segments | Janumet | Int’l
Segment Reporting Information [Line Items]
Sales	272	371	544	762
Pharmaceutical | Operating Segments | Other pharmaceutical
Segment Reporting Information [Line Items]
Sales	553	528	1,138	1,131
Pharmaceutical | Operating Segments | Other pharmaceutical | U.S.
Segment Reporting Information [Line Items]
Sales	171	157	342	317
Pharmaceutical | Operating Segments | Other pharmaceutical | Int’l
Segment Reporting Information [Line Items]
Sales	382	372	793	814
Animal Health | Operating Segments
Segment Reporting Information [Line Items]
Sales	1,456	1,467	2,947	2,949
Animal Health | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Sales	475	477	956	951
Animal Health | Operating Segments | Int’l
Segment Reporting Information [Line Items]
Sales	982	990	1,991	1,998
Animal Health | Operating Segments | Livestock
Segment Reporting Information [Line Items]
Sales	807	826	1,656	1,658
Animal Health | Operating Segments | Livestock | U.S.
Segment Reporting Information [Line Items]
Sales	165	164	338	335
Animal Health | Operating Segments | Livestock | Int’l
Segment Reporting Information [Line Items]
Sales	643	662	1,318	1,322
Animal Health | Operating Segments | Companion Animal
Segment Reporting Information [Line Items]
Sales	649	641	1,291	1,291
Animal Health | Operating Segments | Companion Animal | U.S.
Segment Reporting Information [Line Items]
Sales	310	313	618	616
Animal Health | Operating Segments | Companion Animal | Int’l
Segment Reporting Information [Line Items]
Sales	$ 339	$ 328	$ 673	$ 676

Segment Reporting - Consolidate

Segment Reporting - Consolidated Sales by Geographic Area (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenue from External Customer [Line Items]
Sales	$ 15,035	$ 14,593	$ 29,522	$ 30,494
United States
Revenue from External Customer [Line Items]
Sales	7,018	6,238	13,676	13,577
Europe, Middle East and Africa
Revenue from External Customer [Line Items]
Sales	3,348	3,582	6,651	7,942
China
Revenue from External Customer [Line Items]
Sales	1,913	1,372	3,628	2,515
Asia Pacific (other than China and Japan)
Revenue from External Customer [Line Items]
Sales	848	1,008	1,694	1,938
Japan
Revenue from External Customer [Line Items]
Sales	675	1,114	1,434	2,103
Latin America
Revenue from External Customer [Line Items]
Sales	742	642	1,403	1,249
Other
Revenue from External Customer [Line Items]
Sales	$ 491	$ 637	$ 1,036	$ 1,170

Segment Reporting - Reconciliat

Segment Reporting - Reconciliation of Segment Profits to Income before Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Profits	$ (5,335)	$ 4,487	$ (1,685)	$ 9,348
Interest income	109	15	221	22
Interest expense	(277)	(240)	(519)	(483)
Amortization			(1,020)	(1,163)
Depreciation			(874)	(895)
Research and development	(13,321)	(2,798)	(17,597)	(5,374)
Restructuring costs	(151)	(142)	(218)	(194)
Operating Segments
Segment Reporting Information [Line Items]
Profits	10,321	9,744	20,025	19,829
Operating Segments | Pharmaceutical segment
Segment Reporting Information [Line Items]
Profits	9,854	9,173	18,993	18,673
Operating Segments | Animal Health segment
Segment Reporting Information [Line Items]
Profits	467	571	1,032	1,156
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Profits	19	260	184	454
Segment Reconciling Items
Segment Reporting Information [Line Items]
Interest income	109	15	221	22
Interest expense	(277)	(240)	(519)	(483)
Amortization	(477)	(463)	(1,020)	(1,163)
Depreciation	(376)	(431)	(775)	(809)
Research and development	(13,194)	(2,652)	(17,341)	(5,097)
Restructuring costs	(151)	(142)	(218)	(194)
Charge for Zetia antitrust litigation settlements	0	0	(573)	0
Other unallocated, net	$ (1,309)	$ (1,604)	$ (1,669)	$ (3,211)