MERCK & CO., INC., 10-Q filed on 8/5/2025
Quarterly Report
v3.25.2
Cover Page - shares
 6 Months Ended
Jun. 30, 2025
Jul. 31, 2025
Entity Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2025  
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   2,497,783,211
Amendment Flag false  
Document Fiscal Year Focus 2025  
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 ($0.50 par value)  
Trading Symbol MRK  
Security Exchange Name NYSE  
1.875% Notes due 2026    
Entity Information [Line Items]    
Title of 12(b) Security 1.875% Notes due 2026  
Trading Symbol MRK/26  
Security Exchange Name NYSE  
3.250% Notes due 2032    
Entity Information [Line Items]    
Title of 12(b) Security 3.250% Notes due 2032  
Trading Symbol MRK/32  
Security Exchange Name NYSE  
2.500% Notes due 2034    
Entity Information [Line Items]    
Title of 12(b) Security 2.500% Notes due 2034  
Trading Symbol MRK/34  
Security Exchange Name NYSE  
1.375% Notes due 2036    
Entity Information [Line Items]    
Title of 12(b) Security 1.375% Notes due 2036  
Trading Symbol MRK 36A  
Security Exchange Name NYSE  
3.500% Notes due 2037    
Entity Information [Line Items]    
Title of 12(b) Security 3.500% Notes due 2037  
Trading Symbol MRK/37  
Security Exchange Name NYSE  
3.700% Notes due 2044    
Entity Information [Line Items]    
Title of 12(b) Security 3.700% Notes due 2044  
Trading Symbol MRK/44  
Security Exchange Name NYSE  
3.750% Notes due 2054    
Entity Information [Line Items]    
Title of 12(b) Security 3.750% Notes due 2054  
Trading Symbol MRK/54  
Security Exchange Name NYSE  
v3.25.2
CONDENSED CONSOLIDATED STATEMENT OF INCOME - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Income Statement [Abstract]        
Sales $ 15,806 $ 16,112 $ 31,335 $ 31,887
Costs, Expenses and Other        
Cost of sales 3,557 3,745 6,976 7,285
Selling, general and administrative 2,649 2,739 5,202 5,221
Research and development 4,048 3,500 7,669 7,492
Restructuring costs 560 80 629 202
Other (income) expense, net (7) 42 (43) 12
Total Costs, Expenses and Other 10,807 10,106 20,433 20,212
Income Before Taxes 4,999 6,006 10,902 11,675
Taxes on Income 571 545 1,388 1,447
Net Income 4,428 5,461 9,514 10,228
Less: Net Income Attributable to Noncontrolling Interests 1 6 8 11
Net Income Attributable to Merck & Co., Inc. $ 4,427 $ 5,455 $ 9,506 $ 10,217
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 1.76 $ 2.15 $ 3.78 $ 4.03
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 1.76 $ 2.14 $ 3.77 $ 4.02
v3.25.2
CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Statement of Comprehensive Income [Abstract]        
Net Income Attributable to Merck & Co., Inc. $ 4,427 $ 5,455 $ 9,506 $ 10,217
Other Comprehensive Loss Net of Taxes:        
Net unrealized (loss) gain on derivatives, net of reclassifications (410) 67 (627) 197
Benefit plan net loss and prior service cost, net of amortization (8) (10) (26) (15)
Cumulative translation adjustment (38) (144) 177 (382)
Other comprehensive income (loss), net of taxes (456) (87) (476) (200)
Comprehensive Income Attributable to Merck & Co., Inc. $ 3,971 $ 5,368 $ 9,030 $ 10,017
v3.25.2
CONDENSED CONSOLIDATED BALANCE SHEET - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Current Assets    
Cash and cash equivalents $ 8,007 $ 13,242
Short-term investments 615 447
Accounts receivable (net of allowance for doubtful accounts of $94 in 2025 and $89 in 2024) 11,846 10,278
Inventories (excludes inventories of $4,882 in 2025 and $4,193 in 2024 classified in Other assets - see Note 6) 6,601 6,109
Other current assets 9,996 8,706
Total current assets 37,065 38,782
Investments 774 463
Property, Plant and Equipment, at cost, net of accumulated depreciation of $20,256 in 2025 and $19,155 in 2024 25,236 23,779
Goodwill 21,591 21,668
Other Intangibles, Net 15,193 16,370
Other Assets 17,664 16,044
Total Assets 117,523 117,106
Current Liabilities    
Loans payable and current portion of long-term debt 1,434 2,649
Trade accounts payable 3,892 4,079
Accrued and other current liabilities 14,502 15,694
Income taxes payable 4,156 3,914
Dividends payable 2,053 2,084
Total current liabilities 26,037 28,420
Long-Term Debt 33,968 34,462
Deferred Income Taxes 1,427 1,387
Other Noncurrent Liabilities 7,031 6,465
Merck & Co., Inc. Stockholders’ Equity    
Common stock, $0.50 par value Authorized - 6,500,000,000 shares Issued - 3,577,103,522 shares in 2025 and 2024 1,788 1,788
Other paid-in capital 44,644 44,704
Retained earnings 68,477 63,069
Accumulated other comprehensive loss (5,421) (4,945)
Stockholders' equity before deduction for treasury stock 109,488 104,616
Less treasury stock, at cost: 1,073,963,194 shares in 2025 and 1,049,466,187 shares in 2024 60,495 58,303
Total Merck & Co., Inc. stockholders’ equity 48,993 46,313
Noncontrolling Interests 67 59
Total equity 49,060 46,372
Liabilities and Equity $ 117,523 $ 117,106
v3.25.2
CONDENSED CONSOLIDATED BALANCE SHEET (Parenthetical) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Statement of Financial Position [Abstract]    
Allowance for doubtful accounts $ 94 $ 89
Inventories classified in other assets 4,882 4,193
Accumulated depreciation $ 20,256 $ 19,155
Common stock, par value (in dollars per share) $ 0.50 $ 0.50
Common stock, authorized (in 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) 1,073,963,194 1,049,466,187
v3.25.2
CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Cash Flows from Operating Activities    
Net income $ 9,514 $ 10,228
Adjustments to reconcile net income to net cash provided by operating activities:    
Amortization 1,198 1,087
Depreciation 1,020 1,029
Income from investments in equity securities, net (189) (200)
Charge for research and development asset acquisition 0 656
Deferred income taxes (634) (232)
Share-based compensation 411 379
Other 444 174
Net changes in assets and liabilities (5,971) (4,394)
Net Cash Provided by Operating Activities 5,793 8,727
Cash Flows from Investing Activities    
Capital expenditures (2,092) (1,652)
Purchases of securities and other investments (1,207) (64)
Proceeds from sales of securities and other investments 1,057 320
Acquisition of Harpoon Therapeutics, Inc., net of cash acquired 0 (746)
Other (15) (303)
Net Cash Used in Investing Activities (2,257) (2,445)
Cash Flows from Financing Activities    
Net change in short-term borrowings 48 0
Proceeds from issuance of debt 0 3,600
Payments on debt (2,500) (751)
Dividends paid to stockholders (4,127) (3,936)
Purchases of treasury stock (2,509) (373)
Proceeds from exercise of stock options 31 160
Other (254) (298)
Net Cash Used in Financing Activities (9,311) (1,598)
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash 530 (220)
Net (Decrease) Increase in Cash, Cash Equivalents and Restricted Cash (5,245) 4,464
Cash, Cash Equivalents and Restricted Cash at Beginning of Year (includes restricted cash of $76 and $68 at January 1, 2025 and 2024, respectively, included in Other current assets) 13,318 6,909
Cash, Cash Equivalents and Restricted Cash at End of Period (includes restricted cash of $66 and $69 at June 30, 2025 and 2024, respectively, included in Other current assets) $ 8,073 $ 11,373
v3.25.2
CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Parenthetical) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Jun. 30, 2024
Dec. 31, 2023
Statement of Cash Flows [Abstract]        
Restricted cash $ 66 $ 76 $ 69 $ 68
v3.25.2
Basis of Presentation
 6 Months Ended
Jun. 30, 2025
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.) for complete consolidated financial statements are not included herein. These interim statements should be read in conjunction with the audited financial statements and notes thereto included in Merck’s Form 10-K filed on February 25, 2025.
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 Issued Accounting Standards Not Yet Adopted
In December 2023, the Financial Accounting Standards Board (FASB) issued guidance intended to improve the transparency of income tax disclosures by requiring consistent categories and disaggregation of information in the effective income tax rate reconciliation and income taxes paid disclosures by jurisdiction. The guidance also includes other amendments to improve the effectiveness of income tax disclosures by removing certain previously required disclosures. The guidance is effective for 2025 annual reporting and will result in incremental disclosures within the footnotes to the Company’s financial statements.
In November 2024, the FASB issued guidance intended to improve financial reporting by requiring entities to disclose additional information about specific expense categories at interim and annual reporting periods. The guidance is effective for 2027 annual reporting and 2028 interim reporting. Early adoption is permitted. The guidance, which can be applied on a prospective or retrospective basis, will result in incremental disclosures within the footnotes to the Company’s financial statements.
v3.25.2
Acquisitions, Research Collaborations and Licensing Agreements
 6 Months Ended
Jun. 30, 2025
Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract]  
Acquisitions, Research Collaborations and Licensing 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; expense reimbursements or payments to the third party; milestone, royalty or profit share arrangements contingent upon the occurrence of certain future events linked to the success of the asset in development; and can also include option and continuation payments. 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.
2025 Transactions
In July 2025, Merck entered into a definitive agreement to acquire Verona Pharma plc (Verona Pharma), a biopharmaceutical company focused on respiratory diseases, for $107 per American Depository Share (each of which represents eight Verona Pharma ordinary shares) for a total transaction value of approximately $10 billion. Through this acquisition, Merck will acquire Ohtuvayre (ensifentrine), a first-in-class selective dual inhibitor of phosphodiesterases 3 and 4 (PDE3 and PDE4), which was approved in the U.S. in June 2024 for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in adult patients and is also being evaluated in clinical trials for the treatment of non-cystic fibrosis bronchiectasis. Closing of the acquisition is expected in the fourth quarter of 2025, but is subject to certain conditions, including approval under the Hart-Scott-Rodino Antitrust Improvements Act, approval of Verona Pharma’s shareholders, sanction by the High Court of Justice of England and Wales and other customary conditions. If the proposed transaction closes, the Company expects to capitalize most of the purchase price as an intangible asset for Ohtuvayre.
In May 2025, Merck and Jiangsu Hengrui Pharmaceuticals Co., Ltd. (Hengrui Pharma) closed an exclusive license agreement for MK-7262 (HRS-5346), an investigational oral small molecule Lipoprotein(a) inhibitor, which is currently being evaluated in a Phase 2 clinical trial in China. Under the agreement, Hengrui Pharma granted Merck exclusive rights to develop, manufacture and commercialize MK-7262 (HRS-5346) worldwide, excluding the Greater China region. The agreement provides for an upfront payment of $200 million, which was recorded as a charge to Research and development expenses in the second quarter of 2025. Hengrui Pharma is also eligible to receive future contingent developmental milestone payments of up to $92.5 million, regulatory milestone payments of up to $177.5 million and sales-based milestone payments of up to $1.5 billion, as well as tiered royalties ranging from a mid-single-digit rate to a low-double-digit rate on future net sales of MK-7262 (HRS-5346), if approved.
In March 2025, Merck acquired the Dundalk, Ireland facility of WuXi Vaccines (a wholly owned subsidiary of WuXi Biologics), which was accounted for as an asset acquisition. Merck paid $437 million at closing which, combined with previous consideration transferred under a prior manufacturing arrangement with WuXi Vaccines related to this facility, resulted in $759 million being recorded as assets under construction within Property, Plant and Equipment. There are no future contingent payments associated with the acquisition.
2024 Transactions
In March 2024, Merck acquired Harpoon Therapeutics, Inc. (Harpoon), a clinical-stage immunotherapy company developing a novel class of T-cell engagers designed to harness the power of the body’s immune system to treat patients suffering from cancer and other diseases, for $765 million and also incurred $56 million of transaction costs. Harpoon’s lead candidate, gocatamig (MK-6070, formerly HPN328), is a T-cell engager targeting delta-like ligand 3 (DLL3), an inhibitory canonical Notch ligand that is expressed at high levels in small-cell lung cancer and neuroendocrine tumors. The transaction was accounted for as an asset acquisition since gocatamig represented substantially all of the fair value of the gross assets acquired (excluding cash and deferred income taxes). Merck recorded net assets of $165 million, as well as a charge of $656 million to Research and development expenses in the first six months of 2024 related to the transaction. There are no future contingent payments associated with the acquisition. In August 2024, Merck and Daiichi Sankyo expanded their existing global co-development and co-commercialization agreement to include gocatamig. See Note 3 for more information on Merck’s collaboration with Daiichi Sankyo.
v3.25.2
Collaborative Arrangements
 6 Months Ended
Jun. 30, 2025
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 are developing and commercializing 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 share the development and commercialization costs for Lynparza and Koselugo monotherapy and non-PD-1/PD-L1 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 six months of 2025, Merck made sales-based milestone payments aggregating $700 million to AstraZeneca of which $600 million related to Lynparza and $100 million related to Koselugo (both of which had been previously accrued for). Potential future sales-based milestone payments of $2.0 billion have not yet been accrued as they are not deemed by the Company to be probable at this time. Lynparza received a regulatory approval triggering a capitalized milestone payment from Merck to AstraZeneca of $245 million in the first six months of 2024 (which had been previously accrued for). The partners have agreed that no future regulatory milestone payments from Merck to AstraZeneca are likely under the agreement.
The intangible asset balances related to Lynparza and Koselugo (which reflect the capitalized sales-based and regulatory milestone payments attributed to each product) were $1.0 billion and $44 million, respectively, at June 30, 2025 and are included in Other Intangibles, Net. The assets are being amortized over their estimated useful lives (through 2028 for Lynparza and through 2029 for Koselugo) as supported by projected future cash flows, subject to impairment testing.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Alliance revenue - Lynparza$370 $317 $682 $609 
Alliance revenue - Koselugo43 37 87 75 
Total alliance revenue$413 $354 $769 $684 
Cost of sales (1)
86 82 169 163 
Selling, general and administrative40 43 72 82 
Research and development16 18 28 38 
($ in millions)June 30, 2025December 31, 2024
Receivables from AstraZeneca included in Other current assets
$411 $424 
Payables to AstraZeneca included in Accrued and other current liabilities (2)
12 713 
(1)    Represents amortization of capitalized milestone payments.
(2)    Balance at December 31, 2024 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 are developing and commercializing 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 six months of 2024, Merck made a $125 million sales-based milestone payment to Eisai (which had been previously accrued for). Potential future sales-based milestone payments of $2.3 billion have not yet been accrued as they are not deemed by the Company to be probable at this time. 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 $321 million at June 30, 2025 and is included in Other Intangibles, Net. The amount is being amortized over its estimated useful life through 2026 as supported by projected future cash flows, subject to impairment testing.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Alliance revenue - Lenvima$265 $249 $523 $504 
Cost of sales (1)
60 60 121 121 
Selling, general and administrative35 41 66 80 
Research and development3 6 7 13 
($ in millions)June 30, 2025December 31, 2024
Receivables from Eisai included in Other current assets
$265 $257 
(1)    Represents amortization of capitalized milestone payments.
Bayer AG
In 2014, the Company entered into a worldwide clinical development collaboration with Bayer AG (Bayer) to market and develop soluble guanylate cyclase (sGC) modulators including Bayer’s Adempas (riociguat) and Verquvo (vericiguat). The two companies have implemented a joint development and commercialization strategy. 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. There are no sales-based milestone payments remaining under this collaboration.
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 $348 million and $43 million, respectively, at June 30, 2025 and are included in Other Intangibles, Net. The assets are being amortized over their estimated useful lives (through 2027 for Adempas and through 2031 for Verquvo) as supported by projected future cash flows, subject to impairment testing.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Alliance revenue - Adempas/Verquvo$123 $106 $229 $203 
Net sales of Adempas recorded by Merck80 72 147 142 
Net sales of Verquvo recorded by Merck11 9 21 16 
Total sales$214 $187 $397 $361 
Cost of sales (1)
61 61 120 123 
Selling, general and administrative29 26 58 59 
Research and development20 28 43 55 
($ in millions)June 30, 2025December 31, 2024
Receivables from Bayer included in Other current assets
$173 $160 
Payables to Bayer included in Accrued and other current liabilities
88 82 
(1)    Includes amortization of intangible assets, cost of products sold by Merck, as well as Bayer’s share of profits from sales in Merck’s marketing territories.
Ridgeback Biotherapeutics LP
In 2020, Merck and Ridgeback Biotherapeutics LP (Ridgeback), a closely held biotechnology company, entered into a collaboration agreement to develop Lagevrio (molnupiravir), an investigational orally available antiviral candidate for the treatment of patients with COVID-19. Merck gained exclusive worldwide rights to develop and commercialize Lagevrio and related molecules. Following initial authorizations in certain markets in 2021, Lagevrio has since received multiple additional authorizations.
Under the terms of the agreement, Ridgeback received an upfront payment and is eligible to receive future contingent payments dependent upon the achievement of certain developmental and regulatory approval milestones. The agreement also provides for Merck to reimburse Ridgeback for a portion of certain third-party contingent milestone payments and royalties on net sales, which is part of the profit-sharing calculation. Merck is the principal on sales transactions, recognizing sales and related costs, with profit-sharing amounts recorded within Cost of sales. Profits from the collaboration are split equally between the partners. Reimbursements from Ridgeback for its share of research and development costs (deducted from Ridgeback’s share of profits) are reflected as decreases to Research and development expenses.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Net sales of Lagevrio recorded by Merck
$83 $110 $185 $460 
Cost of sales (1)
44 96 97 287 
Selling, general and administrative
14 16 28 32 
Research and development
6 7 14 2 
($ in millions)June 30, 2025December 31, 2024
Payables to Ridgeback included in Accrued and other current liabilities (2)
$31 $68 
(1)    Includes cost of products sold by Merck, Ridgeback’s share of profits, royalty expense, amortization of capitalized milestone payments and inventory reserves.
(2)    Includes accrued royalties.
Daiichi Sankyo
In 2023, Merck and Daiichi Sankyo entered into a global development and commercialization agreement for three of Daiichi Sankyo’s DXd antibody drug conjugate (ADC) candidates: patritumab deruxtecan (HER3-DXd) (MK-1022), ifinatamab deruxtecan (I-DXd) (MK-2400) and raludotatug deruxtecan (R-DXd) (MK-5909). All three potentially first-in-class DXd ADCs are in various stages of clinical development for the treatment of multiple solid tumors both as monotherapy and/or in combination with other treatments. The companies will jointly develop and potentially commercialize these ADC candidates worldwide, except in Japan where Daiichi Sankyo will maintain exclusive rights. Daiichi Sankyo will be solely responsible for manufacturing and supply.
Under the terms of the agreement, Merck made payments to Daiichi Sankyo totaling $4.0 billion in 2023. These payments included $1.0 billion ($500 million each for patritumab deruxtecan and ifinatamab deruxtecan) which may be refundable on a pro-rated basis in the event of early termination of development with respect to either program. In addition, the agreement provided for a continuation payment of $750 million related to patritumab deruxtecan, which Merck paid in October 2024, and a continuation payment of $750 million related to raludotatug deruxtecan due from Merck in October 2025. If Merck does not make the remaining continuation payment for raludotatug deruxtecan, the rights for that program will revert to Daiichi Sankyo and the non-refundable upfront payments already paid will be retained by Daiichi Sankyo. The agreement also provides for contingent payments from Merck to Daiichi Sankyo of up to an additional $5.5 billion for each DXd ADC upon the successful achievement of certain sales-based milestones. In conjunction with this transaction, Merck recorded an aggregate pretax charge of $5.5 billion to Research and development expenses in 2023 for the $4.0 billion of upfront payments and the $1.5 billion of continuation payments.
Merck and Daiichi Sankyo equally share research and development costs, except for raludotatug deruxtecan, where Merck is responsible for 75% of the first $2.0 billion of research and development expenses. Merck includes its share of development costs associated with the collaboration as part of Research and development expenses. Following regulatory approval, Daiichi Sankyo will generally record sales worldwide (Daiichi Sankyo will be the principal on sales transactions) and the companies will equally share expenses as well as profits worldwide except for Japan where Daiichi Sankyo retains exclusive rights and Merck will receive a 5% sales-based royalty. Merck will record its share of product sales, net of cost of sales and commercialization costs, as alliance revenue.
In August 2024, Merck and Daiichi Sankyo expanded their agreement to include gocatamig (MK-6070), an investigational delta-like ligand 3 (DLL3) targeting T-cell engager, which Merck obtained through its acquisition of Harpoon (see Note 2). The companies are planning to evaluate gocatamig in combination with ifinatamab deruxtecan in certain patients with small-cell-lung cancer, as well as other potential combinations. Merck received an upfront cash payment of $170 million from Daiichi Sankyo (recorded within Other (income) expense, net) and has also satisfied a contingent quid obligation from the original collaboration agreement. The companies will jointly develop and commercialize gocatamig worldwide and share research and development, as well as commercialization expenses. Research and development expenses related to gocatamig in combination with ifinatamab deruxtecan will be shared in a manner consistent with the original agreement for ifinatamab deruxtecan. Merck will be solely responsible for manufacturing and supply of gocatamig. If approved, Merck will generally record sales for gocatamig worldwide (Merck will be the principal on sales transactions) and the companies will equally share expenses as well as profits worldwide, except for Japan where Merck retains exclusive rights and Daiichi Sankyo will receive a 5% sales-based royalty.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Selling, general and administrative $4 $14 $13 $16 
Research and development
193 65 321 133 
($ in millions)June 30, 2025December 31, 2024
Receivables from Daiichi Sankyo included in Other current assets
$21 $8 
Payables to Daiichi Sankyo included in Accrued and other current liabilities (1)
850 817 
(1) Includes accrued continuation payment.
Moderna, Inc.
In 2022, Merck exercised its option to jointly develop and commercialize intismeran autogene (V940/mRNA-4157), an investigational individualized neoantigen therapy, pursuant to the terms of an existing collaboration and license agreement with Moderna, Inc. (Moderna). Intismeran autogene is currently being evaluated in combination with Keytruda in multiple Phase 3 clinical trials. Merck and Moderna share costs and will share any profits equally under this worldwide collaboration. Merck records its share of development costs associated with the collaboration as part of Research and development expenses. Any reimbursements received from Moderna for research and development expenses are recognized as reductions to Research and development costs. Merck has also capitalized certain of the shared costs, mainly related to facility costs, which aggregated $232 million at June 30, 2025 and will be amortized over the assets’ estimated useful lives.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Selling, general and administrative $6 $4 $12 $6 
Research and development
90 93 176 162 
($ in millions)June 30, 2025December 31, 2024
Payables to Moderna included in Accrued and other current liabilities
$22 $57 
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 may co-promote any future products approved under this collaboration) in North America, which is reimbursed by BMS. Merck receives tiered royalties ranging from 20% to 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, consisting of royalties (recorded within Sales), was $107 million and $226 million in the second quarter and first six months of 2025, respectively, compared with $90 million and $161 million in the second quarter and first six months of 2024, respectively.
v3.25.2
Restructuring
 6 Months Ended
Jun. 30, 2025
Restructuring and Related Activities [Abstract]  
Restructuring Restructuring
In July 2025, the Company approved a new restructuring program (2025 Restructuring Program) designed to position the Company for its next chapter of growth and to successfully advance its pipeline and launch new products across multiple therapeutic areas. As part of this program, the Company expects to eliminate certain positions in sales and administrative organizations, as well as research and development. The Company will, however, continue to hire employees into new roles across all strategic growth areas of the business. In addition, the Company will reduce its global real estate footprint and continue to optimize its manufacturing network, aligning the geography of its global manufacturing footprint to its customers and reflecting changes in the Company’s business. Most actions contemplated under the 2025 Restructuring Program are expected to be largely completed by the end of 2027, with the exception of certain manufacturing actions, which are expected to be substantially completed by the end of 2029. The cumulative pretax costs to be incurred by the Company to implement the program are estimated to be approximately $3.0 billion, of which approximately 60% will be cash, relating primarily to employee separation expense and contractual termination costs. The remainder of the costs will be non-cash, relating primarily to the accelerated depreciation of facilities. The Company recorded total pretax costs of $649 million in the second quarter of 2025 related to the 2025 Restructuring Program.
In January 2024, the Company approved a restructuring program (2024 Restructuring Program) intended to continue the optimization of the Company’s Human Health global manufacturing network as the future pipeline shifts to new modalities and also optimize the Animal Health global manufacturing network to improve supply reliability and increase efficiency. The actions contemplated under the 2024 Restructuring Program are expected to be substantially completed by the end of 2031, with the cumulative pretax costs to be incurred by the Company to implement the program estimated to be approximately $4.0 billion. Approximately 60% of the cumulative pretax costs will be non-cash, relating primarily to the accelerated depreciation of facilities to be closed or divested. The remainder of the costs will result in cash outlays, relating primarily to facility shut-down costs. The Company recorded total pretax costs of $130 million and $177 million in the second quarter of 2025 and 2024, respectively, and $235 million and $422 million in the first six months of 2025 and 2024, respectively, related to the 2024 Restructuring Program. Since inception of the 2024 Restructuring Program through June 30, 2025, Merck has incurred total cumulative pretax costs of $1.3 billion.
For segment reporting, restructuring charges are unallocated expenses.
The following tables summarize the charges related to restructuring program activities by type of cost:
 Three Months Ended June 30, 2025Six Months Ended June 30, 2025
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
Accelerated
Depreciation
Separation Costs
Other Exit Costs
Total
2025 Restructuring Program
Cost of sales$— $— $100 $100 $— $— $100 $100 
Research and development— — 53 53 — — 53 53 
Restructuring costs— 481 15 496 — 481 15 496 
— 481 168 649 — 481 168 649 
2024 Restructuring Program
Cost of sales55 — 10 65 96 — 5 101 
Selling, general and administrative— — 1 1 — — 1 1 
Restructuring costs— 6 58 64 — 7 126 133 
55 6 69 130 96 7 132 235 
$55 $487 $237 $779 $96 $488 $300 $884 
 Three Months Ended June 30, 2024Six Months Ended June 30, 2024
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
Accelerated
Depreciation
Separation Costs
Other Exit Costs
Total
2024 Restructuring Program
Cost of sales$66 $— $— $66 $131 $— $51 $182 
Selling, general and administrative— — 31 31 — — 36 36 
Research and development— — — — — — 2 2 
Restructuring costs— 19 61 80 — 111 91 202 
$66 $19 $92 $177 $131 $111 $180 $422 
Accelerated depreciation costs primarily relate to manufacturing, research and administrative facilities to be fully or partially closed or divested and equipment to be disposed of as part of the programs. Accelerated depreciation costs represent the difference between the depreciation expense to be recognized over the revised useful life of the asset, based upon the anticipated date the site will be closed or divested or the equipment disposed of, and depreciation expense as determined utilizing the useful life prior to the restructuring actions. All the sites will continue to operate up through the respective closure dates and, since future undiscounted cash flows are sufficient to recover the respective book values, Merck is recording accelerated depreciation over the revised useful life of the site assets. Anticipated site closure dates, particularly related to manufacturing locations, have been and may continue to be adjusted to reflect changes resulting from regulatory or other factors.
Separation costs are associated with actual headcount reductions, as well as involuntary headcount reductions which were probable and could be reasonably estimated.
Other exit costs in 2025 and 2024 include asset impairment, facility shut-down, contractual termination, and other related costs, as well as pretax gains and losses resulting from the sales of facilities and related assets. Additionally, other activity includes certain employee-related costs associated with pension and other postretirement benefit plans (see Note 9) and share-based compensation.
The following table summarizes the charges and spending related to restructuring program activities for the six months ended June 30, 2025:
($ in millions)
Accelerated Depreciation
Separation
Costs
Other Exit Costs
Total
2025 Restructuring Program
Restructuring reserves January 1, 2025$— $— $— $— 
Expenses
— 481 168 649 
Non-cash activity— — (53)(53)
Restructuring reserves June 30, 2025$— $481 $115 $596 
2024 Restructuring Program
Restructuring reserves January 1, 2025
$— $564 $— $564 
Expenses96 7 132 235 
(Payments) receipts, net— (23)(126)(149)
Non-cash activity(96)— (6)(102)
Restructuring reserves June 30, 2025
$— $548 $— $548 
v3.25.2
Financial Instruments
 6 Months Ended
Jun. 30, 2025
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 foreign 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. The amount reclassified into earnings as a result of the discontinuation of cash flow hedges because it was no longer deemed probable the forecasted hedged transactions would occur was not material for the second quarter or first six months of either 2025 or 2024. 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 foreign 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 foreign 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 foreign exchange rate and the cost of the hedging instrument (primarily the euro, Swiss franc, Japanese yen, and Chinese renminbi). 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 foreign 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. Certain of 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 Income are shown below:
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income (1)
Amount of Pretax Gain 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)20252024202520242025202420252024
Net Investment Hedging Relationships
Foreign exchange contracts$38 $5 $65 $3 $(5)$(1)$(8)$(1)
Euro-denominated notes411 (34)541 (96)— — — — 
(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.
At June 30, 2025, the Company was a party to seven pay-floating, receive-fixed interest rate swap contracts designated as fair value hedges of a portion of fixed-rate notes as detailed in the table below.
June 30, 2025
($ in millions)
Par Value of Debt
Number of Interest Rate Swaps Held
Total Swap Notional Amount
4.50% notes due 2033
$1,500 6 $1,500 
    5.00% notes due 2053
1,500 1 250
The interest rate swap contracts are designated hedges of the fair value changes in the notes attributable to changes in the benchmark Secured Overnight Financing Rate (SOFR) swap rate. The fair value changes in the notes attributable to changes in the SOFR swap rate are recorded in interest expense along with the offsetting fair value changes in the swap contracts. The cash flows from these contracts are reported as operating activities in the Condensed Consolidated Statement of Cash Flows. In August 2025, the Company entered into several forward starting swaps, each with a notional amount of $250 million.
The table below presents the location of amounts recorded in the Condensed Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges:
Carrying Amount of Hedged Liabilities
Cumulative Amount of Fair Value Hedging Adjustment Increase Included in the Carrying Amount
($ in millions)
June 30, 2025December 31, 2024June 30, 2025December 31, 2024
Balance Sheet Caption
Long-Term Debt
$1,814 $1,509 $75 $17 
Presented in the table below is the fair value of derivatives on a gross basis segregated between those derivatives that are designated as hedging instruments and those that are not designated as hedging instruments:
  June 30, 2025December 31, 2024
  Fair Value of DerivativeU.S. Dollar
Notional		Fair Value of DerivativeU.S. Dollar
Notional
($ in millions)AssetLiabilityAssetLiability
Derivatives Designated as Hedging InstrumentsBalance Sheet Caption
Interest rate swap contracts
Other Assets
$76 $— $1,750 $17 $— $1,500 
Foreign exchange contractsOther current assets23 — 2,289 323 — 8,662 
Foreign exchange contractsOther Assets29 — 2,076 66 — 2,125 
Foreign exchange contractsAccrued and other current liabilities— 433 8,732 — 1 162 
Foreign exchange contractsOther Noncurrent Liabilities— 16 556 — 1 16 
  $128 $449 $15,403 $406 $2 $12,465 
Derivatives Not Designated as Hedging InstrumentsBalance Sheet Caption      
Foreign exchange contractsOther current assets$417 $— $15,819 $323 $— $12,544 
Foreign exchange contractsOther Assets1 — 475 — — — 
Foreign exchange contractsAccrued and other current liabilities— 405 12,522 — 343 13,551 
Foreign exchange contractsOther Noncurrent Liabilities— 1 475 — — — 
  $418 $406 $29,291 $323 $343 $26,095 
  $546 $855 $44,694 $729 $345 $38,560 
As noted above, the Company records its derivatives on a gross basis in the Condensed Consolidated Balance Sheet. The Company has master netting agreements with several of its financial institution counterparties (see Concentrations of Credit Risk below). The following table provides information on the Company’s derivative positions subject to these master netting arrangements as if they were presented on a net basis, allowing for the right of offset by counterparty and cash collateral exchanged per the master agreements and related credit support annexes:
 June 30, 2025December 31, 2024
($ in millions)AssetLiabilityAssetLiability
Gross amounts recognized in the condensed consolidated balance sheet$546 $855 $729 $345 
Gross amounts subject to offset in master netting arrangements not offset in the condensed consolidated balance sheet(445)(445)(299)(299)
Cash collateral received/posted
(4)(97)(165)— 
Net amounts$97 $313 $265 $46 
The table below provides information regarding the location and amount of pretax gains and losses of derivatives designated in fair value or cash flow hedging relationships:
Three Months Ended June 30,Six Months Ended June 30,
($ in millions)202520242025202420252024202520242025202420252024
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)
$15,806 $16,112 $(7)$42 $(456)$(87)$31,335 $31,887 $(43)$12 $(476)$(200)
Loss (gain) on fair value hedging relationships:
Interest rate swap contracts
Hedged items— — 20 4 — — — — 58 (26)— — 
Derivatives designated as hedging instruments— — (19)(4)— — — — (58)27 — — 
Impact of cash flow hedging relationships:
Foreign exchange contracts
Amount of (loss) gain recognized in OCI on derivatives
— — — — (542)139 — — — — (743)348 
(Decrease) increase in Sales as a result of AOCL reclassifications
(23)54 — — 23 (54)50 98 — — (50)(98)
Interest rate contracts
Amount of gain recognized in Other (income) expense, net on derivatives
— — — — — — — — (1)(1)— — 
Amount of loss recognized in OCI on derivatives
— — — — — — — — — — (1)(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)2025202420252024
Derivatives Not Designated as Hedging InstrumentsIncome Statement Caption
Foreign exchange contracts (1)
Other (income) expense, net$(237)$9 $(256)$75 
Foreign exchange contracts (2)
Sales17 (10)34 (20)
(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, 2025, the Company estimates $473 million of pretax net unrealized losses on derivatives maturing within the next 12 months that hedge foreign currency denominated sales over that same period will be reclassified from AOCL to Sales. The amount ultimately reclassified to Sales may differ as foreign exchange rates change. Realized gains and losses are ultimately determined by actual foreign exchange rates at maturity.
Investments in Debt and Equity Securities
Information on investments in debt and equity securities is as follows:
 June 30, 2025December 31, 2024
 Amortized
Cost		Gross UnrealizedFair
Value		Amortized
Cost		Gross UnrealizedFair
Value
($ in millions)GainsLossesGainsLosses
Commercial paper$416 $— $— $416 $348 $— $— $348 
U.S. government and agency securities290 — — 290 188 — — 188 
Foreign government bonds
1 — — 1 — — — — 
Total debt securities$707 $— $— $707 $536 $— $— $536 
Publicly traded equity securities (1)
1,181 920 
Total debt and publicly traded equity securities$1,888 $1,456 
(1)    Unrealized net gains of $147 million and $262 million were recorded in Other (income) expense, net in the second quarter and first six months of 2025, respectively, on equity securities still held at June 30, 2025. Unrealized net losses (gains) of $8 million and $(125) million were recorded in Other (income) expense, net in the second quarter and first six months of 2024, respectively, on equity securities still held at June 30, 2024.
At June 30, 2025 and June 30, 2024, the Company also had $870 million and $936 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 2025, the Company recorded unrealized losses of $33 million related to certain of these equity investments still held at June 30, 2025. During the first six months of 2024, the Company recorded unrealized gains of $61 million and unrealized losses of $5 million related to certain of these equity investments still held at June 30, 2024. 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, 2025 were $307 million and $131 million, respectively.
At June 30, 2025 and June 30, 2024, the Company also had $221 million and $278 million, respectively, recorded in Other Assets for equity securities held through ownership interests in investment funds. Losses (gains) recorded in Other (income) expense, net relating to these investment funds were $27 million and $(7) million for the second quarter of 2025 and 2024, respectively, and were $50 million and $(5) million for the first six months of 2025 and 2024, respectively.
Fair Value Measurements
Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company uses a fair value hierarchy which maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value. There are three levels of inputs used to measure fair value with Level 1 having the highest priority and Level 3 having the lowest:
Level 1 - Quoted prices (unadjusted) in active markets for identical assets or liabilities.
Level 2 - Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
Level 3 - Unobservable inputs that are supported by little or no market activity. Level 3 assets or liabilities are those whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques with significant unobservable inputs, as well as assets or liabilities for which the determination of fair value requires significant judgment or estimation.
If the inputs used to measure the financial assets and liabilities fall within more than one level described above, the categorization is based on the lowest level input that is significant to the fair value measurement of the instrument.
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis
Financial assets and liabilities measured at fair value on a recurring basis are summarized below:
Fair Value Measurements UsingFair Value Measurements Using
 Level 1Level 2Level 3TotalLevel 1Level 2Level 3Total
($ in millions)June 30, 2025December 31, 2024
Assets
Investments
Commercial paper$— $416 $— $416 $— $348 $— $348 
U.S. government and agency securities— 198 — 198 — 99 — 99 
Foreign government bonds
— 1 — 1 — — — — 
Publicly traded equity securities774 — — 774 463 — — 463 
 774 615 — 1,389 463 447 — 910 
Other assets (1)
U.S. government and agency securities92 — — 92 89 — — 89 
Publicly traded equity securities (2)
407 — — 407 457 — — 457 
499 — — 499 546 — — 546 
Derivative assets (3)
Forward exchange contracts— 411 — 411 — 499 — 499 
Interest rate swaps
— 76 — 76 — 17 — 17 
Purchased currency options— 59 — 59 — 213 — 213 
 — 546 — 546 — 729 — 729 
Total assets$1,273 $1,161 $— $2,434 $1,009 $1,176 $— $2,185 
Liabilities
Other liabilities
Contingent consideration$— $— $— $— $— $— $193 $193 
Derivative liabilities (3)
Forward exchange contracts— 801 — 801 — 338 — 338 
Written currency options— 54 — 54 — 7 — 7 
— 855 — 855 — 345 — 345 
Total liabilities$— $855 $— $855 $— $345 $193 $538 
(1)    Investments included in other assets are restricted as to use, including for the payment of benefits under employee benefit plans.
(2)    Includes securities with an aggregate fair value of $81 million at December 31, 2024, which were subject to a contractual sale restriction that expired in April 2025.
(3)    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, 2025 and December 31, 2024, Cash and cash equivalents included $7.3 billion and $12.3 billion of cash equivalents, respectively (which would be considered Level 2 in the fair value hierarchy).
Contingent Consideration
Summarized information about the changes in the fair value of liabilities for contingent consideration associated with business combinations is as follows:
($ in millions)20252024
Fair value January 1$193 $354 
Changes in estimated fair value (1)
(52)(3)
Payments (2)
(141)(126)
Fair value June 30
$— $225 
(1)    Recorded in Cost of sales, Research and development expenses, and Other (income) expense, net. Includes cumulative translation adjustments. Amount in 2025 includes the reversal of $45 million for a Zerbaxa sales-based milestone as it was determined that payment was not probable.
(2)    Amount in both periods reflects payments related to the 2016 termination of the Sanofi Pasteur MSD joint venture. Amount in 2025 also includes a $25 million payment related to the achievement of a sales-based milestone for Zerbaxa.
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, 2025, was $31.3 billion compared with a carrying value of $35.4 billion and at December 31, 2024, was $32.6 billion compared with a carrying value of $37.1 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, distributors 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 $1.6 billion and $2.1 billion of accounts receivable as of June 30, 2025 and December 31, 2024, 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, generally within thirty days after receipt. As of June 30, 2025 and December 31, 2024, the Company had collected $43 million and $55 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 is recorded in Accrued and other current liabilities. 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 advanced by the Company to counterparties was $97 million at June 30, 2025. Cash collateral received by the Company from various counterparties was $4 million and $165 million at June 30, 2025 and December 31, 2024, respectively. The obligation to return such collateral is recorded in Accrued and other current liabilities.
v3.25.2
Inventories
 6 Months Ended
Jun. 30, 2025
Inventory Disclosure [Abstract]  
Inventories Inventories
Inventories consisted of:
($ in millions)June 30, 2025December 31, 2024
Finished goods$2,142 $2,022 
Raw materials and work in process9,888 8,831 
Supplies312 289 
Total12,342 11,142 
Decrease to LIFO cost(859)(840)
 $11,483 $10,302 
Recognized as:
Inventories$6,601 $6,109 
Other Assets4,882 4,193 
Amounts recognized as Other Assets are comprised almost entirely of raw materials and work in process inventories. At June 30, 2025 and December 31, 2024, these amounts included $4.3 billion and $3.8 billion, respectively, of inventories not expected to be sold within one year. In addition, these amounts included $572 million and $412 million at June 30, 2025 and December 31, 2024, respectively, of inventories produced in preparation for product launches (primarily MK-3475A, subcutaneous pembrolizumab).
v3.25.2
Contingencies
 6 Months Ended
Jun. 30, 2025
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, commercial litigation, and securities 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. Generally, 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
Dr. Scholl’s Foot Powder
As previously disclosed, Merck is a defendant in product liability lawsuits in the U.S. arising from consumers’ alleged exposure to talc in Dr. Scholl’s foot powder, which Merck acquired through its merger with Schering-Plough Corporation and sold as part of the divestiture of Merck’s consumer care business to Bayer in 2014. In these actions, plaintiffs allege that they were exposed to asbestos-contaminated talc and developed mesothelioma as a result. As of June 30, 2025, approximately 575 cases were pending against Merck in various state courts.
Gardasil/Gardasil 9
As previously disclosed, 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, 2025, approximately 125 cases were filed and are 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 (POTS) as a predominate alleged injury.
In August 2022, the U.S. 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. In February 2024, the multidistrict litigation (Gardasil MDL) was reassigned to Judge Kenneth D. Bell. On March 11, 2025, the court granted Merck’s motion for summary judgment in 16 bellwether cases on implied preemption grounds; plaintiffs have appealed to the Fourth Circuit. The parties’ letter submissions on next steps in the Gardasil MDL proceeding in light of the court’s decision were submitted on April 8, 2025. Expert discovery is set to commence on the remaining alleged conditions on September 2, 2025 with summary judgment briefing to follow.
On March 21, 2025, plaintiff’s co-lead counsel in the Gardasil MDL filed a seven-plaintiff complaint in New Jersey state court. On March 24, 2025, Merck removed the case to federal court and has requested that the U.S. Judicial Panel on Multidistrict Litigation transfer the case to the Gardasil MDL. Plaintiffs have opposed transfer to the Gardasil MDL and have moved to have the case remanded to New Jersey state court.
On May 1, 2025, plaintiff’s co-lead counsel in the Gardasil MDL filed a new six-plaintiff complaint in New Jersey state court. On May 30, 2025, Merck removed the case to federal court and has requested that the U.S. Judicial Panel on Multidistrict Litigation transfer the case to the Gardasil MDL. Plaintiffs have opposed transfer to the Gardasil MDL and have moved to have the case remanded to New Jersey state court.
On January 28, 2025, a trial commenced in California state court. Plaintiff claims that she suffers from POTS and fibromyalgia as a result of her Gardasil vaccinations. On February 14, 2025, after several weeks of trial and an opportunity to litigate plaintiff’s claims before a jury, plaintiff’s counsel approached Merck and proposed that the jury be discharged and the case adjourned. Merck agreed, subject to an explicit stipulation that Merck would provide no financial or other consideration in exchange for the agreement to adjourn. The case has thus been adjourned until a new trial date of September 15, 2025. Merck is vigorously defending this case and believes that evidence presented in court will show that Gardasil had no role in causing any of plaintiff’s conditions.
As previously disclosed, there are fewer than 15 product liability cases pending outside the U.S.
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.
Securities Litigation
As previously disclosed, in February 2025, a putative class action was filed against Merck and certain of its officers in the U.S. District Court for the District of New Jersey, captioned Cronin v. Merck & Co., Inc., et al., purportedly on behalf of all purchasers of Merck common stock between February 2022 and February 2025. Plaintiff alleges that Merck violated federal securities laws by making materially false and misleading statements and material omissions regarding demand for Gardasil/Gardasil 9 in China. Plaintiff seeks unspecified monetary damages, pre-judgment and post-judgment interest, and fees and costs. On April 7, 2025, the court entered a joint stipulation staying the defendants’ deadline to respond to the complaint until after a lead plaintiff is appointed and requiring the parties to confer and jointly propose deadlines for amending and responding to the complaint within 14 days of the lead plaintiff appointment. Lead plaintiff motions were filed on April 14, 2025, and remain pending.
On July 18, 2025, purported Merck stockholder Terence Collins filed a derivative lawsuit in the U.S. District Court for the District of New Jersey, captioned Collins v. Davis, et al., against certain Merck officers and board members. The complaint asserts claims of violation of the Exchange Act, breach of fiduciary duty, waste of corporate assets, and unjust enrichment based on the same allegations as in the putative securities class action. On behalf of the Company, the complaint seeks unspecified monetary damages, corporate governance reforms, injunctive relief, restitution, and fees and costs.
Commercial and Other Litigation
Zetia Antitrust Litigation
As previously disclosed, Merck, MSD, Schering Corporation, Schering-Plough Corporation, and MSP Singapore Company LLC (collectively, the Merck Defendants) were defendants in a number of lawsuits filed in 2018 on behalf of direct and indirect purchasers of Zetia (ezetimibe) 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 (Zetia MDL) before Judge Rebecca Beach Smith in the Eastern District of Virginia. In April 2023, the Merck Defendants reached settlements with the direct purchaser and retailer plaintiffs and a settlement with the indirect purchaser class that the court approved in October 2023.
As previously disclosed, in 2020 and 2021, United HealthCare Services, Inc. (United HealthCare), Humana Inc. (Humana), Centene Corporation and others (Centene), and Kaiser Foundation Health Plan, Inc. (Kaiser) (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 were transferred to the Eastern District of Virginia to proceed with the Zetia MDL.
In December 2023, the U.S. Judicial Panel on Multidistrict Litigation remanded the four Insurer Plaintiff cases to the transferor courts in the Northern District of California (Kaiser), the District of Minnesota (United HealthCare), and the District of New Jersey (Humana and Centene). The Merck Defendants filed motions to dismiss in each of the Insurer Plaintiff cases.
In December 2024, the district court in the District of New Jersey granted in part and denied in part the motions to dismiss in the Humana and Centene cases and, on January 29, 2025, Humana and Centene filed amended complaints. On March 5, 2025, the Merck Defendants filed motions to dismiss the amended complaints. On March 24, 2025, the Merck Defendants filed a third-party complaint against AmerisourceBergen Drug Corp., AmerisourceBergen Corp., and Cencora, Inc., (collectively, Cencora) seeking indemnification and a declaration of rights for Humana’s direct purchaser claims. On June 23, 2025, Cencora moved to dismiss the third-party complaint or, in the alternative, to transfer the third-party action to the Eastern District of Virginia.
On February 25, 2025, the district court in the District of Minnesota granted in part and denied in part the motion to dismiss in the United HealthCare case. On March 11, 2025, the Merck Defendants filed an answer and affirmative defenses in response to United HealthCare’s complaint. On March 24, 2025, the Merck Defendants filed a third-party complaint against Cardinal Health, Inc., Cardinal Health 110, LLC, and Cardinal Health 112, LLC (collectively, Cardinal), seeking indemnification and a declaration of rights for certain of United HealthCare’s direct and indirect purchaser claims. On June 6, 2025, Cardinal filed a motion to dismiss the Merck Defendants’ third-party complaint on forum grounds, or in the alternative, to stay the Merck Defendants’ third-party claims pending arbitration.
On March 18, 2025, the district court in the Northern District of California granted in part and denied in part the motion to dismiss in the Kaiser case. The court granted Kaiser leave to amend its complaint, and Kaiser filed its second amended complaint on April 15, 2025. On May 20, 2025, the Merck Defendants moved to dismiss certain claims in the second amended complaint.
Patent Litigation
From time to time, generic and biosimilar manufacturers of pharmaceutical products file abbreviated New Drug Applications (ANDAs) and Biologics License Applications, respectively, with the U.S. Food and Drug Administration (FDA) seeking to market generic and biosimilar 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 and biosimilar 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. In addition to these matters, the Company may be involved in other litigation involving its intellectual property and intellectual property owned or licensed by other companies.
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 had 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 in August 2022 in favor of proceeding in New Jersey. The remaining defendants in the New Jersey action have 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 in December 2022 on this remaining PTE calculation defense.
In June 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 five-year extension. Also in June 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. In July 2023, the defendants filed a notice of appeal with the U.S. Court of Appeals for the Federal Circuit. Oral argument took place on February 4, 2025. On March 13, 2025, the Federal Circuit affirmed the district court’s decision, holding that the patent term extension granted to the sugammadex patent covering Bridion was not invalid and that the patent is entitled to its full five-year patent term extension. The FDA has now granted Bridion six months of pediatric exclusivity. Thus, the Federal Circuit’s decision secures Bridion’s exclusivity in the U.S. through July 27, 2026.
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.
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 (salt/polymorph patent).
As previously disclosed, beginning in 2019, a number of generic drug companies filed ANDAs seeking approval of generic forms of Januvia and Janumet along with Paragraph IV certifications challenging the validity of the salt/polymorph patent. The Company has settled with over two dozen generic companies providing that these generic companies can bring their generic versions of Januvia and Janumet to the market in the U.S. 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 salt/polymorph patent based on the filing of Zydus’s NDA seeking approval of a form of sitagliptin that is different from than that used in Januvia. 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.
In January 2023, the Company received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying the Company that Zydus filed an ANDA seeking approval of sitagliptin/metformin HCl tablets. 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. In November 2023, the Company received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying the Company that Zydus filed an ANDA seeking approval of sitagliptin/metformin HCl Extended Release tablets. In January 2024, the parties reached settlement enabling Zydus to seek final approval of a non-automatically substitutable version containing a different form of sitagliptin than that used in Janumet XR.
As a result of these 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 Zydus has received FDA approval for a non-automatically substitutable form of sitagliptin that differs from the form in the Company’s sitagliptin products.
In March 2024, the Company received another Paragraph IV Certification Letter under the Hatch-Waxman Act from Azurity Pharmaceuticals, Inc. (Azurity) asserting that a different sitagliptin product subject to its ANDA does not infringe the salt/polymorph patent. In May 2024, Merck filed a civil action in the U.S. District Court of Delaware alleging infringement. The case
was dismissed without prejudice in July 2024. Following the dismissal, the Company granted Azurity a covenant not to assert the salt/polymorph patent against the Azurity product that is the subject of such ANDA.
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 that could impact the validity of the Janumet SPCs in Europe. A decision rendered in December 2024 provides guidance on points of law and does not directly apply to the Janumet SPCs. Thus, additional proceedings in certain countries where generic companies were prevented from launching products during the SPC period may be necessary to determine whether the SPCs are valid and if not, whether damages are appropriate. 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.
In October 2023, the Company filed a patent infringement lawsuit against Sawai Pharmaceuticals Co., Ltd. and Medisa Shinyaku Co., Ltd (collectively, Defendants) in the Tokyo District Court seeking an injunction to stop the manufacture, sale and offer for sale of the Defendants’ sitagliptin dihydrogen phosphate product, while the Company’s patents and patent term extensions are in force. The lawsuit is in response to the Defendants’ application for marketing authorization to sell a generic sitagliptin dihydrogen phosphate product, in the anhydrate form, which was approved in August 2023. Merck asserts that the Defendants’ activity infringes a patent term extension associated with Merck’s patent directed to the sitagliptin compound patent.
Keytruda — As previously disclosed, in November 2022, the Company filed a complaint against The Johns Hopkins University (JHU) in the U.S. District Court of Maryland. This action concerns a joint research collaboration between Merck and JHU regarding the use of Keytruda in certain indications. 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) (the Joint Clinical Study). Subsequently JHU obtained a number of U.S. patents specifically relying on the Joint Clinical Study. Merck alleges that JHU breached the collaboration agreement by obtaining issuance of these patents without informing or involving Merck, which were licensed to others, and then trying to enforce these patents against Merck. Merck therefore brought an action for breach of contract, declaratory judgment of noninfringement, and promissory estoppel. JHU answered the complaint in April and May 2023, denying Merck’s claims, and counterclaiming for willful infringement of nine issued U.S. patents, including a demand for damages. Between November 30, 2023, and March 13, 2024, the Company filed inter partes review petitions with the United States Patent Office’s Patent Trial and Appeal Board (PTAB), challenging the patentability of all nine patents asserted in the district court. Between June 2024 and October 2024, the PTAB instituted a review of all nine challenged patents. In June 2024, the district court granted Merck’s motion to stay the case in its entirety pending the outcome of the PTAB proceeding instituted in June 2024.
On June 9, 2025, the PTAB issued its final decision finding all claims of the first challenged JHU Patent (e.g., U.S. Patent No. 11,591,393) unpatentable. JHU has filed a request asking for the Director of the United States Patent & Trademark Office to review that decision.
Because the PTAB institution decisions for the nine different JHU patents were staggered between June 2024 and October 2024, the decision issued on June 9, 2025 is only with respect to the first challenged patent. The Company expects subsequent final decisions in the eight remaining proceedings in the fall. The district court’s stay is expected to continue until at least the issuance of all subsequent final decisions.
Subcutaneous Pembrolizumab — Halozyme, Inc. has publicly alleged that certain patents in its modified hyaluronidase (MDASE) portfolio cover the Company’s subcutaneous pembrolizumab candidate, which is currently under review by the FDA. In November 2024, the Company began filing a series of post grant review (PGR) petitions before the PTAB alleging that certain patents in the MDASE portfolio are invalid. On June 2, 2025, the PTAB instituted the first petition filed by the Company. Since then, the PTAB also instituted three additional petitions. Institution decisions on 10 additional patents in the MDASE portfolio are still pending.
On April 24, 2025, Halozyme, Inc. filed a complaint in the U.S. District Court for the District of New Jersey alleging that the Company’s activities related to subcutaneous pembrolizumab infringe or will infringe 15 patents belonging to the MDASE portfolio, 12 of which are the subject of the Company’s already filed PGR petitions. Although there are three patents that were not and cannot be challenged using the PGR process, the Company believes those patents are invalid and suffer from the same defects as the patents currently being challenged and those patents can be challenged in court proceedings if required.
Lynparza — As previously disclosed, between December 2022 and November 2024, AstraZeneca Pharmaceuticals LP received Paragraph IV Certification Letters under the Hatch-Waxman Act notifying AstraZeneca that Natco Pharma Limited, Sandoz Inc., Cipla USA, Inc and Cipla Limited (collectively Cipla), and Zydus Pharmaceuticals (USA) Inc. have filed separate applications to the FDA seeking pre-patent expiry approval to sell generic versions of Lynparza (olaparib) tablet. Between February 2023 and January 2025, AstraZeneca and the Company filed a series of patent infringement lawsuits in the U.S. District Court for the District of New Jersey against each generic company asserting a number of Orange-Book listed patents. The filing of the initial infringement suit generally stays FDA approval for 30 months from the date of the Paragraph IV notice or until an adverse court decision, if any, whichever may occur earlier. In these cases, however, none of the generic companies are challenging the patent specifically claiming the olaparib compound which expires in September 2027. Thus, the earliest date the FDA can approve any of the currently pending generic applications is September 2027. All cases have been consolidated and a trial is expected in 2026.
Other Litigation
There are various other pending legal proceedings involving the Company, principally product liability and intellectual property lawsuits. While it is not feasible to predict the outcome of such proceedings, in the opinion of the Company, either the likelihood of loss is remote or any reasonably possible loss associated with the resolution of such proceedings is not expected to be material to the Company’s financial condition, results of operations or cash flows either individually or in the aggregate.
Legal Defense Reserves
Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable. Some of the significant factors considered in the review of these legal defense reserves are as follows: the actual costs incurred by the Company; the development of the Company’s legal defense strategy and structure in light of the 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, 2025 and December 31, 2024 of approximately $255 million and $225 million, respectively, represents the Company’s best estimate of the minimum amount of defense costs to be incurred in connection with its outstanding litigation; however, events such as additional trials and other events that could arise in the course of its litigation could affect the ultimate amount of legal defense costs to be incurred by the Company. The Company will continue to monitor its legal defense costs and review the adequacy of the associated reserves and may determine to increase the reserves at any time in the future if, based upon the factors set forth, it believes it would be appropriate to do so.
v3.25.2
Equity
 6 Months Ended
Jun. 30, 2025
Equity [Abstract]  
Equity Equity
Three Months Ended June 30,
   Common StockOther
Paid-In
Capital		Retained
Earnings		Accumulated
Other
Comprehensive
Loss		 Treasury StockNon-
controlling
Interests		Total
($ and shares in millions except per share amounts)SharesPar ValueSharesCost
Balance at April 1, 2024
3,577 $1,788 $44,598 $56,697 $(5,274)1,044 $(57,445)$60 $40,424 
Net income attributable to Merck & Co., Inc.
— — — 5,455 — — — — 5,455 
Other comprehensive loss, net of taxes— — — — (87)— — — (87)
Cash dividends declared on common stock ($0.77 per share)
— — — (1,965)— — — — (1,965)
Treasury stock shares purchased— — — — — 2 (251)— (251)
Share-based compensation plans and other— — (236)— — (5)302 — 66 
Net income attributable to noncontrolling interests— — — — — — — 6 6 
Balance at June 30, 20243,577 $1,788 $44,362 $60,187 $(5,361)1,041 $(57,394)$66 $43,648 
Balance at April 1, 2025
3,577 $1,788 $44,816 $66,097 $(4,965)1,061 $(59,401)$65 $48,400 
Net income attributable to Merck & Co., Inc.— — — 4,427 — — — — 4,427 
Other comprehensive loss, net of taxes
— — — — (456)— — — (456)
Cash dividends declared on common stock ($0.81 per share)
— — — (2,047)— — — — (2,047)
Treasury stock shares purchased— — — — — 17 (1,345)— (1,345)
Share-based compensation plans and other— — (172)— — (4)251 1 80 
Net income attributable to noncontrolling interests— — — — — — — 1 1 
Balance at June 30, 20253,577 $1,788 $44,644 $68,477 $(5,421)1,074 $(60,495)$67 $49,060 
Six Months Ended June 30,
   Common StockOther
Paid-In
Capital		Retained
Earnings		Accumulated
Other
Comprehensive
Loss		 Treasury StockNon-
controlling
Interests		Total
($ and shares in millions except per share amounts)SharesPar ValueSharesCost
Balance at January 1, 2024
3,577 $1,788 $44,509 $53,895 $(5,161)1,045 $(57,450)$54 $37,635 
Net income attributable to Merck & Co., Inc.
— — — 10,217 — — — — 10,217 
Other comprehensive loss, net of taxes— — — — (200)— — — (200)
Cash dividends declared on common stock ($1.54 per share)
— — — (3,925)— — — — (3,925)
Treasury stock shares purchased— — — — — 3 (373)— (373)
Share-based compensation plans and other— — (147)— — (7)429 1 283 
Net income attributable to noncontrolling interests— — — — — — — 11 11 
Balance at June 30, 20243,577 $1,788 $44,362 $60,187 $(5,361)1,041 $(57,394)$66 $43,648 
Balance at January 1, 2025
3,577 $1,788 $44,704 $63,069 $(4,945)1,049 $(58,303)$59 $46,372 
Net income attributable to Merck & Co., Inc.— — — 9,506 — — — — 9,506 
Other comprehensive loss, net of taxes— — — — (476)— — — (476)
Cash dividends declared on common stock ($1.62 per share)
— — — (4,098)— — — — (4,098)
Treasury stock shares purchased— — — — — 29 (2,509)— (2,509)
Share-based compensation plans and other— — (60)— — (4)317 — 257 
Net income attributable to noncontrolling interests— — — — — — — 8 8 
Balance at June 30, 20253,577 $1,788 $44,644 $68,477 $(5,421)1,074 $(60,495)$67 $49,060 
v3.25.2
Pension and Other Postretirement Benefit Plans
 6 Months Ended
Jun. 30, 2025
Retirement Benefits [Abstract]  
Pension and Other Postretirement Benefit Plans Pension and Other Postretirement Benefit Plans
The Company has defined benefit pension plans covering eligible employees in the U.S. and in certain of its international subsidiaries. The net periodic benefit cost (credit) of such plans consisted of the following components: 
Three Months Ended
June 30,		Six Months Ended
June 30,
2025202420252024
($ in millions)U.S.InternationalU.S.InternationalU.S.InternationalU.S.International
Service cost$90 $60 $86 $60 $180 $114 $173 $122 
Interest cost141 75 134 73 282 146 269 147 
Expected return on plan assets(210)(152)(207)(137)(420)(295)(417)(278)
Amortization of unrecognized prior service credit
— (4)— (3)— (8)— (6)
Net loss amortization
13 2 10 1 25 5 20 3 
Termination benefits— — — — — — 4 — 
 $34 $(19)$23 $(6)$67 $(38)$49 $(12)
The Company provides medical benefits, principally to its eligible U.S. retirees and similar benefits to their dependents, through its other postretirement benefit plans. The net credit of such plans consisted of the following components: 
  Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Service cost$9 $8 $19 $15 
Interest cost16 14 31 28 
Expected return on plan assets(13)(20)(26)(40)
Amortization of unrecognized prior service credit(10)(11)(20)(21)
Net gain amortization(10)(12)(20)(24)
 $(8)$(21)$(16)$(42)
In connection with restructuring actions (see Note 4), termination charges were recorded on pension plans related to expanded eligibility for certain employees exiting Merck.
The components of net periodic benefit cost (credit) other than the service cost component are included in Other (income) expense, net (see Note 10), with the exception of certain amounts for termination benefits which are recorded in Restructuring costs if the event giving rise to the termination benefits related to restructuring actions.
v3.25.2
Other (Income) Expense, Net
 6 Months Ended
Jun. 30, 2025
Other Income and Expenses [Abstract]  
Other (Income) Expense, Net Other (Income) Expense, Net
Other (income) expense, net, consisted of: 
 Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Interest income$(69)$(69)$(178)$(141)
Interest expense305 310 618 613 
Exchange losses78 60 167 144 
Income from investments in equity securities, net (1)
(100)(56)(189)(200)
Net periodic defined benefit plan (credit) cost other than service cost(152)(159)(300)(319)
Other, net(69)(44)(161)(85)
 $(7)$42 $(43)$12 
(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.
Interest paid for the six months ended June 30, 2025 and 2024 was $616 million and $581 million, respectively.
v3.25.2
Income Taxes
 6 Months Ended
Jun. 30, 2025
Income Tax Disclosure [Abstract]  
Income Taxes Income Taxes
The effective income tax rates of 11.4% and 12.7% for the second quarter and first six months of 2025, respectively, reflect a 2.9 percentage point favorable impact and a 1.4 percentage point favorable impact, respectively, due to $146 million of tax benefits resulting primarily from favorable audit adjustments. The effective income tax rates in both the second quarter and first six months of 2025 also reflect the favorable impacts of geographical mix of income and expense, as well as certain discrete items.
The effective income tax rates of 9.1% and 12.4% for the second quarter and first six months of 2024, respectively, reflect a 4.3 percentage point favorable impact and a 2.2 percentage point favorable impact, respectively, due to a $259 million reduction in reserves for unrecognized income tax benefits resulting from the expiration in June 2024 of the statute of limitations for assessments related to the 2019 federal tax return year. The effective income tax rate for the first six months of 2024 also reflects a 0.7 percentage point unfavorable impact of a charge for the acquisition of Harpoon for which no tax benefit was recognized.
While many jurisdictions in which Merck operates have adopted the global minimum tax provision of the Organization for Economic Cooperation and Development (OECD) Pillar 2, effective for tax years beginning in January 2024, it resulted in a minimal impact to the Company’s 2024 effective income tax rate due to the accounting for the tax effects of intercompany transactions. The Company expects the impact of the global minimum tax to be approximately 2% for full year 2025. In addition, in July 2025, H.R.1 - One Big Beautiful Bill Act (OBBBA) was enacted into law. The Company is currently evaluating the effects of the OBBBA but does not expect a material tax impact.
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 Tax Cuts and Jobs Act of 2017 (TCJA). In April 2025, Merck received Notices of Proposed Adjustment (NOPAs) that would increase the amount of the one-time transition tax on certain undistributed earnings of foreign subsidiaries by approximately $1.3 billion. In addition, the NOPAs included penalties of approximately $260 million. These amounts are exclusive of any interest that may be due. The Company disagrees with the proposed adjustments and will vigorously contest the NOPAs through all available administrative and, if necessary, judicial proceedings. It is expected to take a number of years to reach resolution of this matter. If the Company is ultimately unsuccessful in defending its position, the impact could be material to its financial statements. The statute of limitations for assessments with respect to the 2019 and 2020 federal tax return years expired in June 2024 and October 2024, respectively. The IRS is also currently conducting examinations of the Company’s tax returns for the years 2021 and 2022. In addition, various state and foreign examinations are in progress.
v3.25.2
Earnings Per Share
 6 Months Ended
Jun. 30, 2025
Earnings Per Share [Abstract]  
Earnings Per Share Earnings Per Share
The calculations of earnings per share are as follows:
 Three Months Ended
June 30,		Six Months Ended
June 30,
($ and shares in millions except per share amounts)2025202420252024
Net Income Attributable to Merck & Co., Inc.
$4,427 $5,455 $9,506 $10,217 
Average common shares outstanding2,510 2,534 2,516 2,534 
Common shares issuable (1)
3 10 6 10 
Average common shares outstanding assuming dilution 2,513 2,544 2,522 2,544 
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders
$1.76 $2.15 $3.78 $4.03 
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders
$1.76 $2.14 $3.77 $4.02 
(1)    Issuable primarily under share-based compensation plans.
For the second quarter of 2025 and 2024, 19 million and 7 million, respectively, and for the first six months of 2025 and 2024, 12 million and 5 million, respectively, of common shares issuable under share-based compensation plans were excluded from the computations of earnings per common share assuming dilution because the effect would have been antidilutive.
v3.25.2
Other Comprehensive Income (Loss)
 6 Months Ended
Jun. 30, 2025
Equity [Abstract]  
Other Comprehensive Income (Loss) Other Comprehensive Income (Loss)
Changes in each component of other comprehensive income (loss) are as follows:
Three Months Ended June 30,
($ in millions)DerivativesEmployee
Benefit
Plans		Foreign Currency
Translation
Adjustment		Accumulated Other
Comprehensive
Loss
Balance April 1, 2024, net of taxes
$106 $(2,798)$(2,582)$(5,274)
Other comprehensive income (loss) before reclassification adjustments, pretax139 1 (157)(17)
Tax(29)2 (7)(34)
Other comprehensive income (loss) before reclassification adjustments, net of taxes110 3 (164)(51)
Reclassification adjustments, pretax(55)
(1)
(15)
(2)
20 (50)
Tax12 2 — 14 
Reclassification adjustments, net of taxes(43)

(13)

20 (36)
Other comprehensive income (loss), net of taxes67 (10)(144)(87)
Balance June 30, 2024, net of taxes
$173 $(2,808)$(2,726)$(5,361)
Balance April 1, 2025, net of taxes
$25 $(2,345)$(2,645)$(4,965)
Other comprehensive income (loss) before reclassification adjustments, pretax(542)(1)134 (409)
Tax114 (1)(172)(59)
Other comprehensive income (loss) before reclassification adjustments, net of taxes(428)(2)(38)(468)
Reclassification adjustments, pretax23 
(1)
(8)
(2)
— 15 
Tax(5)2 — (3)
Reclassification adjustments, net of taxes18 

(6)

— 12 
Other comprehensive income (loss), net of taxes(410)(8)(38)(456)
Balance June 30, 2025, net of taxes
$(385)$(2,353)$(2,683)$(5,421)
Six Months Ended June 30,
($ in millions)DerivativesEmployee
Benefit
Plans		Foreign Currency
Translation
Adjustment		Accumulated Other
Comprehensive
Loss
Balance January 1, 2024, net of taxes
$(24)$(2,793)$(2,344)$(5,161)
Other comprehensive income (loss) before reclassification adjustments, pretax348 6 (382)(28)
Tax(73)(2)(20)(95)
Other comprehensive income (loss) before reclassification adjustments, net of taxes275 4 (402)(123)
Reclassification adjustments, pretax(99)
(1)
(30)
(2)
20 (109)
Tax21 11 — 32 
Reclassification adjustments, net of taxes(78)(19)20 (77)
Other comprehensive income (loss), net of taxes197 (15)(382)(200)
Balance June 30, 2024, net of taxes
$173 $(2,808)$(2,726)$(5,361)
Balance January 1, 2025, net of taxes
$242 $(2,327)$(2,860)$(4,945)
Other comprehensive income (loss) before reclassification adjustments, pretax(743)(2)334 (411)
Tax156 (1)(157)(2)
Other comprehensive income (loss) before reclassification adjustments, net of taxes(587)(3)177 (413)
Reclassification adjustments, pretax(51)
(1)
(18)
(2)
— (69)
Tax11 (5)— 6 
Reclassification adjustments, net of taxes(40)(23)— (63)
Other comprehensive income (loss), net of taxes(627)(26)177 (476)
Balance June 30, 2025, net of taxes
$(385)$(2,353)$(2,683)$(5,421)
(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 9).
v3.25.2
Segment Reporting
 6 Months Ended
Jun. 30, 2025
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, 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,
2025202420252024
 ($ in millions)U.S.Int’lTotalU.S.Int’lTotalU.S.Int’lTotalU.S.Int’lTotal
Pharmaceutical:
Oncology
Keytruda$4,749 $3,207 $7,956 $4,412 $2,858 $7,270 $9,057 $6,104 $15,161 $8,531 $5,686 $14,217 
Alliance revenue-Lynparza (1)
174 195 370 153 165 317 319 363 682 288 321 609 
Alliance revenue-Lenvima (1)
183 83 265 177 73 249 368 155 523 349 155 504 
Welireg138 24 162 116 10 126 261 39 300 194 17 211 
Alliance revenue-Reblozyl (2)
88 19 107 75 15 90 189 37 226 133 28 161 
Vaccines
Gardasil/Gardasil 9
545 581 1,126 536 1,941 2,478 1,082 1,371 2,453 1,024 3,702 4,727 
ProQuad/M-M-R II/Varivax
481 128 609 490 127 617 903 245 1,148 928 259 1,187 
Vaxneuvance136 93 229 99 90 189 275 184 459 260 148 408 
RotaTeq60 61 121 107 56 163 225 125 349 257 123 379 
Capvaxive
129 — 129 — — — 235 1 236 — — — 
Pneumovax 23
5 33 38 11 48 59 3 76 79 17 103 120 
Hospital Acute Care
Bridion411 50 461 351 104 455 789 113 902 680 215 895 
Prevymis115 113 228 90 98 188 217 219 436 165 197 362 
Dificid83 13 96 79 12 92 155 24 179 147 17 165 
Zerbaxa45 29 74 33 28 62 87 57 145 67 51 118 
Cardiovascular
Winrevair
323 12 336 70 — 70 591 24 615 70 — 70 
Alliance revenue-Adempas/Verquvo (3)
108 15 123 98 8 106 205 23 229 188 16 203 
Adempas— 80 80 — 72 72 — 147 147 — 142 142 
Virology
Lagevrio30 52 83 15 95 110 66 119 185 60 400 460 
Isentress/Isentress HD
48 38 86 43 46 89 99 77 176 93 107 200 
Delstrigo
14 70 83 14 45 60 29 121 150 26 89 116 
Pifeltro
25 16 41 27 12 39 57 29 86 56 25 81 
Neuroscience
Belsomra18 21 40 19 34 53 31 58 90 33 66 99 
Immunology
Simponi— — — — 172 172 — — — — 356 356 
Remicade— — — — 35 35 — — — — 74 74 
Diabetes
Januvia216 155 372 177 227 405 561 360 921 361 463 824 
Janumet68 184 251 17 208 224 133 366 498 55 420 475 
Other pharmaceutical (4)
136 450 584 190 430 618 317 997 1,313 354 899 1,252 
Total Pharmaceutical segment sales8,328 5,722 14,050 7,399 7,009 14,408 16,254 11,434 27,688 14,336 14,079 28,415 
Animal Health:
Livestock190 771 961 168 669 837 384 1,501 1,885 334 1,352 1,686 
Companion Animal309 376 685 287 358 645 617 732 1,349 595 712 1,307 
Total Animal Health segment sales499 1,147 1,646 455 1,027 1,482 1,001 2,233 3,234 929 2,064 2,993 
Total segment sales8,827 6,869 15,696 7,854 8,036 15,890 17,255 13,667 30,922 15,265 16,143 31,408 
Other (5)
9 100 110 22 200 222 104 310 413 89 390 479 
 $8,836 $6,969 $15,806 $7,876 $8,236 $16,112 $17,359 $13,977 $31,335 $15,354 $16,533 $31,887 
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 (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 $16 million and $118 million for the six months ended June 30, 2025 and 2024, respectively, as well as revenue from third-party manufacturing arrangements (including sales to Organon & Co.). Other for the six months ended June 30, 2025 and 2024 also includes $100 million and $76 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 $2.5 billion and $3.3 billion for the three months ended June 30, 2025 and 2024, respectively, and $4.7 billion and $6.6 billion for the six months ended June 30, 2025 and 2024, respectively.
Consolidated sales by geographic area where derived are as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
United States$8,836 $7,876 $17,359 $15,354 
Europe, Middle East and Africa3,659 3,515 7,109 7,078 
Latin America859 858 1,651 1,655 
Asia Pacific (other than China and Japan)785 748 1,474 1,472 
Japan626 686 1,295 1,507 
China446 1,817 1,148 3,589 
Other595 612 1,299 1,232 
 $15,806 $16,112 $31,335 $31,887 
A reconciliation of segment profits to Income Before Taxes is as follows:
Three Months Ended June 30,Six Months Ended June 30,
2025202420252024
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
TotalPharma-ceutical
Animal
Health
TotalPharma-ceutical
Animal
Health
Total
Segment sales$14,050 $1,646 $15,696 $14,408 $1,482 $15,890 $27,688 $3,234 $30,922 $28,415 $2,993 $31,408 
Less segment costs: (1)
Cost of sales1,601 659 1,708 612 3,174 1,258 3,414 1,225 
Selling, general and administrative1,456 284 1,514 270 2,858 544 2,943 523 
Research and development (2)
— 110 — 91 — 205 — 181 
Other segment items (3)
(21)— (14)1 (70)1 (46)— 
Total segment profits$11,014 $593 $11,607 $11,200 $508 $11,708 $21,726 $1,226 $22,952 $22,104 $1,064 $23,168 
Other profits30 129 231 274 
Unallocated:
Interest income69 69 178 141 
Interest expense(305)(310)(618)(613)
Amortization(601)(614)(1,198)(1,087)
Depreciation(455)(450)(896)(902)
Research and development(3,844)(3,360)(7,321)(7,209)
Restructuring costs(560)(80)(629)(202)
Other unallocated, net(942)(1,086)(1,797)(1,895)
$4,999 $6,006 $10,902 $11,675 
(1)    The significant expense categories and amounts align with the segment level information that is regularly provided to the chief operating decision maker.
(2)    Human health-related research and development expenses incurred by Merck Research Laboratories are not allocated to segment profits as noted below.
(3)    Includes equity (income) loss from affiliates and other miscellaneous non-operating expenses.
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. The chief operating decision maker (Merck’s Chief Executive Officer) uses segment profit to allocate resources predominately during the planning and forecasting process. 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 by Merck Research Laboratories (the Company’s research and development division that focuses on human health-related activities), or general and administrative expenses not directly incurred by the segments, 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 amortization of purchase accounting adjustments are not allocated to segments.
Other profits are primarily comprised of miscellaneous corporate profits, as well as operating profits (losses) 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.
Equity income from affiliates and depreciation included in segment profits is as follows:
Three Months Ended June 30,Six Months Ended June 30,
2025202420252024
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
TotalPharma-ceutical
Animal
Health
TotalPharma-ceutical
Animal
Health
Total
Equity income from affiliates
$29 $— $29 $29 $— $29 $86 $— $86 $77 $— $77 
Depreciation
1 62 63 1 67 68 2 122 124 2 125 127 
Property, plant and equipment, net, by geographic area where located is as follows:
($ in millions)
June 30, 2025December 31, 2024
United States$15,182 $14,724 
Europe, Middle East and Africa8,554 7,548 
Asia Pacific (other than China and Japan)
966 982 
China204 202 
Japan144 143 
Latin America135 133 
Other51 47 
$25,236 $23,779 
The Company does not disaggregate assets on a products and services basis for internal management reporting and, therefore, such information is not presented.
v3.25.2
Pay vs Performance Disclosure - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Pay vs Performance Disclosure        
Net Income Attributable to Merck & Co., Inc. $ 4,427 $ 5,455 $ 9,506 $ 10,217
v3.25.2
Insider Trading Arrangements
 3 Months Ended
Jun. 30, 2025
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
v3.25.2
Basis of Presentation (Policies)
 6 Months Ended
Jun. 30, 2025
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.) for complete consolidated financial statements are not included herein. These interim statements should be read in conjunction with the audited financial statements and notes thereto included in Merck’s Form 10-K filed on February 25, 2025.
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 Issued Accounting Standards Not Yet Adopted
Recently Issued Accounting Standards Not Yet Adopted
In December 2023, the Financial Accounting Standards Board (FASB) issued guidance intended to improve the transparency of income tax disclosures by requiring consistent categories and disaggregation of information in the effective income tax rate reconciliation and income taxes paid disclosures by jurisdiction. The guidance also includes other amendments to improve the effectiveness of income tax disclosures by removing certain previously required disclosures. The guidance is effective for 2025 annual reporting and will result in incremental disclosures within the footnotes to the Company’s financial statements.
In November 2024, the FASB issued guidance intended to improve financial reporting by requiring entities to disclose additional information about specific expense categories at interim and annual reporting periods. The guidance is effective for 2027 annual reporting and 2028 interim reporting. Early adoption is permitted. The guidance, which can be applied on a prospective or retrospective basis, will result in incremental disclosures within the footnotes to the Company’s financial statements.
Legal Costs Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable.
v3.25.2
Collaborative Arrangements (Tables)
 6 Months Ended
Jun. 30, 2025
Collaborative Arrangements [Abstract]  
Collaboration Arrangements
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Alliance revenue - Lynparza$370 $317 $682 $609 
Alliance revenue - Koselugo43 37 87 75 
Total alliance revenue$413 $354 $769 $684 
Cost of sales (1)
86 82 169 163 
Selling, general and administrative40 43 72 82 
Research and development16 18 28 38 
($ in millions)June 30, 2025December 31, 2024
Receivables from AstraZeneca included in Other current assets
$411 $424 
Payables to AstraZeneca included in Accrued and other current liabilities (2)
12 713 
(1)    Represents amortization of capitalized milestone payments.
(2)    Balance at December 31, 2024 includes accrued milestone payments.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Alliance revenue - Lenvima$265 $249 $523 $504 
Cost of sales (1)
60 60 121 121 
Selling, general and administrative35 41 66 80 
Research and development3 6 7 13 
($ in millions)June 30, 2025December 31, 2024
Receivables from Eisai included in Other current assets
$265 $257 
(1)    Represents amortization of capitalized milestone payments.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Alliance revenue - Adempas/Verquvo$123 $106 $229 $203 
Net sales of Adempas recorded by Merck80 72 147 142 
Net sales of Verquvo recorded by Merck11 9 21 16 
Total sales$214 $187 $397 $361 
Cost of sales (1)
61 61 120 123 
Selling, general and administrative29 26 58 59 
Research and development20 28 43 55 
($ in millions)June 30, 2025December 31, 2024
Receivables from Bayer included in Other current assets
$173 $160 
Payables to Bayer included in Accrued and other current liabilities
88 82 
(1)    Includes amortization of intangible assets, cost of products sold by Merck, as well as Bayer’s share of profits from sales in Merck’s marketing territories.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Net sales of Lagevrio recorded by Merck
$83 $110 $185 $460 
Cost of sales (1)
44 96 97 287 
Selling, general and administrative
14 16 28 32 
Research and development
6 7 14 2 
($ in millions)June 30, 2025December 31, 2024
Payables to Ridgeback included in Accrued and other current liabilities (2)
$31 $68 
(1)    Includes cost of products sold by Merck, Ridgeback’s share of profits, royalty expense, amortization of capitalized milestone payments and inventory reserves.
(2)    Includes accrued royalties.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Selling, general and administrative $4 $14 $13 $16 
Research and development
193 65 321 133 
($ in millions)June 30, 2025December 31, 2024
Receivables from Daiichi Sankyo included in Other current assets
$21 $8 
Payables to Daiichi Sankyo included in Accrued and other current liabilities (1)
850 817 
(1) Includes accrued continuation payment.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Selling, general and administrative $6 $4 $12 $6 
Research and development
90 93 176 162 
($ in millions)June 30, 2025December 31, 2024
Payables to Moderna included in Accrued and other current liabilities
$22 $57 
v3.25.2
Restructuring (Tables)
 6 Months Ended
Jun. 30, 2025
Restructuring and Related Activities [Abstract]  
Charges Related to Restructuring Program Activities by Type of Cost
The following tables summarize the charges related to restructuring program activities by type of cost:
 Three Months Ended June 30, 2025Six Months Ended June 30, 2025
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
Accelerated
Depreciation
Separation Costs
Other Exit Costs
Total
2025 Restructuring Program
Cost of sales$— $— $100 $100 $— $— $100 $100 
Research and development— — 53 53 — — 53 53 
Restructuring costs— 481 15 496 — 481 15 496 
— 481 168 649 — 481 168 649 
2024 Restructuring Program
Cost of sales55 — 10 65 96 — 5 101 
Selling, general and administrative— — 1 1 — — 1 1 
Restructuring costs— 6 58 64 — 7 126 133 
55 6 69 130 96 7 132 235 
$55 $487 $237 $779 $96 $488 $300 $884 
 Three Months Ended June 30, 2024Six Months Ended June 30, 2024
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
Accelerated
Depreciation
Separation Costs
Other Exit Costs
Total
2024 Restructuring Program
Cost of sales$66 $— $— $66 $131 $— $51 $182 
Selling, general and administrative— — 31 31 — — 36 36 
Research and development— — — — — — 2 2 
Restructuring costs— 19 61 80 — 111 91 202 
$66 $19 $92 $177 $131 $111 $180 $422 
Charges and Spending Relating to Restructuring Activities by Program
The following table summarizes the charges and spending related to restructuring program activities for the six months ended June 30, 2025:
($ in millions)
Accelerated Depreciation
Separation
Costs
Other Exit Costs
Total
2025 Restructuring Program
Restructuring reserves January 1, 2025$— $— $— $— 
Expenses
— 481 168 649 
Non-cash activity— — (53)(53)
Restructuring reserves June 30, 2025$— $481 $115 $596 
2024 Restructuring Program
Restructuring reserves January 1, 2025
$— $564 $— $564 
Expenses96 7 132 235 
(Payments) receipts, net— (23)(126)(149)
Non-cash activity(96)— (6)(102)
Restructuring reserves June 30, 2025
$— $548 $— $548 
v3.25.2
Financial Instruments (Tables)
 6 Months Ended
Jun. 30, 2025
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Effect of Net Investment Hedges on OCI and the Consolidated Statement of Operations
The effects of the Company’s net investment hedges on OCI and the Condensed Consolidated Statement of Income are shown below:
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income (1)
Amount of Pretax Gain Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing
Three Months Ended June 30,Six Months Ended June 30,Three Months Ended June 30,Six Months Ended June 30,
($ in millions)20252024202520242025202420252024
Net Investment Hedging Relationships
Foreign exchange contracts$38 $5 $65 $3 $(5)$(1)$(8)$(1)
Euro-denominated notes411 (34)541 (96)— — — — 
(1)    No amounts were reclassified from AOCL into income related to the sale of a subsidiary.
Summary of Interest Rate Swaps Held
At June 30, 2025, the Company was a party to seven pay-floating, receive-fixed interest rate swap contracts designated as fair value hedges of a portion of fixed-rate notes as detailed in the table below.
June 30, 2025
($ in millions)
Par Value of Debt
Number of Interest Rate Swaps Held
Total Swap Notional Amount
4.50% notes due 2033
$1,500 6 $1,500 
    5.00% notes due 2053
1,500 1 250
Amounts Recorded on Balance Sheet Related to Fair Value Hedges
The table below presents the location of amounts recorded in the Condensed Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges:
Carrying Amount of Hedged Liabilities
Cumulative Amount of Fair Value Hedging Adjustment Increase Included in the Carrying Amount
($ in millions)
June 30, 2025December 31, 2024June 30, 2025December 31, 2024
Balance Sheet Caption
Long-Term Debt
$1,814 $1,509 $75 $17 
Fair Value of Derivatives on a Gross Basis Segregated between those Derivatives that are Designated as Hedging Instruments and those that are Not Designated as Hedging Instruments
Presented in the table below is the fair value of derivatives on a gross basis segregated between those derivatives that are designated as hedging instruments and those that are not designated as hedging instruments:
  June 30, 2025December 31, 2024
  Fair Value of DerivativeU.S. Dollar
Notional		Fair Value of DerivativeU.S. Dollar
Notional
($ in millions)AssetLiabilityAssetLiability
Derivatives Designated as Hedging InstrumentsBalance Sheet Caption
Interest rate swap contracts
Other Assets
$76 $— $1,750 $17 $— $1,500 
Foreign exchange contractsOther current assets23 — 2,289 323 — 8,662 
Foreign exchange contractsOther Assets29 — 2,076 66 — 2,125 
Foreign exchange contractsAccrued and other current liabilities— 433 8,732 — 1 162 
Foreign exchange contractsOther Noncurrent Liabilities— 16 556 — 1 16 
  $128 $449 $15,403 $406 $2 $12,465 
Derivatives Not Designated as Hedging InstrumentsBalance Sheet Caption      
Foreign exchange contractsOther current assets$417 $— $15,819 $323 $— $12,544 
Foreign exchange contractsOther Assets1 — 475 — — — 
Foreign exchange contractsAccrued and other current liabilities— 405 12,522 — 343 13,551 
Foreign exchange contractsOther Noncurrent Liabilities— 1 475 — — — 
  $418 $406 $29,291 $323 $343 $26,095 
  $546 $855 $44,694 $729 $345 $38,560 
Information on Derivative Positions Subject to Master Netting Arrangements as if they were Presented on a Net Basis The following table provides information on the Company’s derivative positions subject to these master netting arrangements as if they were presented on a net basis, allowing for the right of offset by counterparty and cash collateral exchanged per the master agreements and related credit support annexes:
 June 30, 2025December 31, 2024
($ in millions)AssetLiabilityAssetLiability
Gross amounts recognized in the condensed consolidated balance sheet$546 $855 $729 $345 
Gross amounts subject to offset in master netting arrangements not offset in the condensed consolidated balance sheet(445)(445)(299)(299)
Cash collateral received/posted
(4)(97)(165)— 
Net amounts$97 $313 $265 $46 
Location and Amount of Pretax Gains and Losses of Derivatives
The table below provides information regarding the location and amount of pretax gains and losses of derivatives designated in fair value or cash flow hedging relationships:
Three Months Ended June 30,Six Months Ended June 30,
($ in millions)202520242025202420252024202520242025202420252024
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)
$15,806 $16,112 $(7)$42 $(456)$(87)$31,335 $31,887 $(43)$12 $(476)$(200)
Loss (gain) on fair value hedging relationships:
Interest rate swap contracts
Hedged items— — 20 4 — — — — 58 (26)— — 
Derivatives designated as hedging instruments— — (19)(4)— — — — (58)27 — — 
Impact of cash flow hedging relationships:
Foreign exchange contracts
Amount of (loss) gain recognized in OCI on derivatives
— — — — (542)139 — — — — (743)348 
(Decrease) increase in Sales as a result of AOCL reclassifications
(23)54 — — 23 (54)50 98 — — (50)(98)
Interest rate contracts
Amount of gain recognized in Other (income) expense, net on derivatives
— — — — — — — — (1)(1)— — 
Amount of loss recognized in OCI on derivatives
— — — — — — — — — — (1)(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)2025202420252024
Derivatives Not Designated as Hedging InstrumentsIncome Statement Caption
Foreign exchange contracts (1)
Other (income) expense, net$(237)$9 $(256)$75 
Foreign exchange contracts (2)
Sales17 (10)34 (20)
(1)    These derivative contracts primarily mitigate changes in the value of remeasured foreign currency denominated monetary assets and liabilities attributable to changes in foreign currency exchange rates.
(2)    These derivative contracts serve as economic hedges of forecasted transactions.
Information on Investments in Debt and Equity Securities
Information on investments in debt and equity securities is as follows:
 June 30, 2025December 31, 2024
 Amortized
Cost		Gross UnrealizedFair
Value		Amortized
Cost		Gross UnrealizedFair
Value
($ in millions)GainsLossesGainsLosses
Commercial paper$416 $— $— $416 $348 $— $— $348 
U.S. government and agency securities290 — — 290 188 — — 188 
Foreign government bonds
1 — — 1 — — — — 
Total debt securities$707 $— $— $707 $536 $— $— $536 
Publicly traded equity securities (1)
1,181 920 
Total debt and publicly traded equity securities$1,888 $1,456 
(1)    Unrealized net gains of $147 million and $262 million were recorded in Other (income) expense, net in the second quarter and first six months of 2025, respectively, on equity securities still held at June 30, 2025. Unrealized net losses (gains) of $8 million and $(125) million were recorded in Other (income) expense, net in the second quarter and first six months of 2024, respectively, on equity securities still held at June 30, 2024.
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis
Financial assets and liabilities measured at fair value on a recurring basis are summarized below:
Fair Value Measurements UsingFair Value Measurements Using
 Level 1Level 2Level 3TotalLevel 1Level 2Level 3Total
($ in millions)June 30, 2025December 31, 2024
Assets
Investments
Commercial paper$— $416 $— $416 $— $348 $— $348 
U.S. government and agency securities— 198 — 198 — 99 — 99 
Foreign government bonds
— 1 — 1 — — — — 
Publicly traded equity securities774 — — 774 463 — — 463 
 774 615 — 1,389 463 447 — 910 
Other assets (1)
U.S. government and agency securities92 — — 92 89 — — 89 
Publicly traded equity securities (2)
407 — — 407 457 — — 457 
499 — — 499 546 — — 546 
Derivative assets (3)
Forward exchange contracts— 411 — 411 — 499 — 499 
Interest rate swaps
— 76 — 76 — 17 — 17 
Purchased currency options— 59 — 59 — 213 — 213 
 — 546 — 546 — 729 — 729 
Total assets$1,273 $1,161 $— $2,434 $1,009 $1,176 $— $2,185 
Liabilities
Other liabilities
Contingent consideration$— $— $— $— $— $— $193 $193 
Derivative liabilities (3)
Forward exchange contracts— 801 — 801 — 338 — 338 
Written currency options— 54 — 54 — 7 — 7 
— 855 — 855 — 345 — 345 
Total liabilities$— $855 $— $855 $— $345 $193 $538 
(1)    Investments included in other assets are restricted as to use, including for the payment of benefits under employee benefit plans.
(2)    Includes securities with an aggregate fair value of $81 million at December 31, 2024, which were subject to a contractual sale restriction that expired in April 2025.
(3)    The fair value determination of derivatives includes the impact of the credit risk of counterparties to the derivatives and the Company’s own credit risk, the effects of which were not significant.
Information About the Changes in Liabilities for Contingent Consideration
Summarized information about the changes in the fair value of liabilities for contingent consideration associated with business combinations is as follows:
($ in millions)20252024
Fair value January 1$193 $354 
Changes in estimated fair value (1)
(52)(3)
Payments (2)
(141)(126)
Fair value June 30
$— $225 
(1)    Recorded in Cost of sales, Research and development expenses, and Other (income) expense, net. Includes cumulative translation adjustments. Amount in 2025 includes the reversal of $45 million for a Zerbaxa sales-based milestone as it was determined that payment was not probable.
(2)    Amount in both periods reflects payments related to the 2016 termination of the Sanofi Pasteur MSD joint venture. Amount in 2025 also includes a $25 million payment related to the achievement of a sales-based milestone for Zerbaxa.
v3.25.2
Inventories (Tables)
 6 Months Ended
Jun. 30, 2025
Inventory Disclosure [Abstract]  
Inventory, current
Inventories consisted of:
($ in millions)June 30, 2025December 31, 2024
Finished goods$2,142 $2,022 
Raw materials and work in process9,888 8,831 
Supplies312 289 
Total12,342 11,142 
Decrease to LIFO cost(859)(840)
 $11,483 $10,302 
Recognized as:
Inventories$6,601 $6,109 
Other Assets4,882 4,193 
Inventory, noncurrent
Inventories consisted of:
($ in millions)June 30, 2025December 31, 2024
Finished goods$2,142 $2,022 
Raw materials and work in process9,888 8,831 
Supplies312 289 
Total12,342 11,142 
Decrease to LIFO cost(859)(840)
 $11,483 $10,302 
Recognized as:
Inventories$6,601 $6,109 
Other Assets4,882 4,193 
v3.25.2
Equity (Tables)
 6 Months Ended
Jun. 30, 2025
Equity [Abstract]  
Schedule of Equity
Three Months Ended June 30,
   Common StockOther
Paid-In
Capital		Retained
Earnings		Accumulated
Other
Comprehensive
Loss		 Treasury StockNon-
controlling
Interests		Total
($ and shares in millions except per share amounts)SharesPar ValueSharesCost
Balance at April 1, 2024
3,577 $1,788 $44,598 $56,697 $(5,274)1,044 $(57,445)$60 $40,424 
Net income attributable to Merck & Co., Inc.
— — — 5,455 — — — — 5,455 
Other comprehensive loss, net of taxes— — — — (87)— — — (87)
Cash dividends declared on common stock ($0.77 per share)
— — — (1,965)— — — — (1,965)
Treasury stock shares purchased— — — — — 2 (251)— (251)
Share-based compensation plans and other— — (236)— — (5)302 — 66 
Net income attributable to noncontrolling interests— — — — — — — 6 6 
Balance at June 30, 20243,577 $1,788 $44,362 $60,187 $(5,361)1,041 $(57,394)$66 $43,648 
Balance at April 1, 2025
3,577 $1,788 $44,816 $66,097 $(4,965)1,061 $(59,401)$65 $48,400 
Net income attributable to Merck & Co., Inc.— — — 4,427 — — — — 4,427 
Other comprehensive loss, net of taxes
— — — — (456)— — — (456)
Cash dividends declared on common stock ($0.81 per share)
— — — (2,047)— — — — (2,047)
Treasury stock shares purchased— — — — — 17 (1,345)— (1,345)
Share-based compensation plans and other— — (172)— — (4)251 1 80 
Net income attributable to noncontrolling interests— — — — — — — 1 1 
Balance at June 30, 20253,577 $1,788 $44,644 $68,477 $(5,421)1,074 $(60,495)$67 $49,060 
Six Months Ended June 30,
   Common StockOther
Paid-In
Capital		Retained
Earnings		Accumulated
Other
Comprehensive
Loss		 Treasury StockNon-
controlling
Interests		Total
($ and shares in millions except per share amounts)SharesPar ValueSharesCost
Balance at January 1, 2024
3,577 $1,788 $44,509 $53,895 $(5,161)1,045 $(57,450)$54 $37,635 
Net income attributable to Merck & Co., Inc.
— — — 10,217 — — — — 10,217 
Other comprehensive loss, net of taxes— — — — (200)— — — (200)
Cash dividends declared on common stock ($1.54 per share)
— — — (3,925)— — — — (3,925)
Treasury stock shares purchased— — — — — 3 (373)— (373)
Share-based compensation plans and other— — (147)— — (7)429 1 283 
Net income attributable to noncontrolling interests— — — — — — — 11 11 
Balance at June 30, 20243,577 $1,788 $44,362 $60,187 $(5,361)1,041 $(57,394)$66 $43,648 
Balance at January 1, 2025
3,577 $1,788 $44,704 $63,069 $(4,945)1,049 $(58,303)$59 $46,372 
Net income attributable to Merck & Co., Inc.— — — 9,506 — — — — 9,506 
Other comprehensive loss, net of taxes— — — — (476)— — — (476)
Cash dividends declared on common stock ($1.62 per share)
— — — (4,098)— — — — (4,098)
Treasury stock shares purchased— — — — — 29 (2,509)— (2,509)
Share-based compensation plans and other— — (60)— — (4)317 — 257 
Net income attributable to noncontrolling interests— — — — — — — 8 8 
Balance at June 30, 20253,577 $1,788 $44,644 $68,477 $(5,421)1,074 $(60,495)$67 $49,060 
v3.25.2
Pension and Other Postretirement Benefit Plans (Tables)
 6 Months Ended
Jun. 30, 2025
Pension Plans  
Defined Benefit Plan Disclosure [Line Items]  
Net Benefit Costs
The Company has defined benefit pension plans covering eligible employees in the U.S. and in certain of its international subsidiaries. The net periodic benefit cost (credit) of such plans consisted of the following components: 
Three Months Ended
June 30,		Six Months Ended
June 30,
2025202420252024
($ in millions)U.S.InternationalU.S.InternationalU.S.InternationalU.S.International
Service cost$90 $60 $86 $60 $180 $114 $173 $122 
Interest cost141 75 134 73 282 146 269 147 
Expected return on plan assets(210)(152)(207)(137)(420)(295)(417)(278)
Amortization of unrecognized prior service credit
— (4)— (3)— (8)— (6)
Net loss amortization
13 2 10 1 25 5 20 3 
Termination benefits— — — — — — 4 — 
 $34 $(19)$23 $(6)$67 $(38)$49 $(12)
Other Postretirement Benefit Plans  
Defined Benefit Plan Disclosure [Line Items]  
Net Benefit Costs
The Company provides medical benefits, principally to its eligible U.S. retirees and similar benefits to their dependents, through its other postretirement benefit plans. The net credit of such plans consisted of the following components: 
  Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Service cost$9 $8 $19 $15 
Interest cost16 14 31 28 
Expected return on plan assets(13)(20)(26)(40)
Amortization of unrecognized prior service credit(10)(11)(20)(21)
Net gain amortization(10)(12)(20)(24)
 $(8)$(21)$(16)$(42)
v3.25.2
Other (Income) Expense, Net (Tables)
 6 Months Ended
Jun. 30, 2025
Other Income and Expenses [Abstract]  
Other (Income) Expense, Net
Other (income) expense, net, consisted of: 
 Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
Interest income$(69)$(69)$(178)$(141)
Interest expense305 310 618 613 
Exchange losses78 60 167 144 
Income from investments in equity securities, net (1)
(100)(56)(189)(200)
Net periodic defined benefit plan (credit) cost other than service cost(152)(159)(300)(319)
Other, net(69)(44)(161)(85)
 $(7)$42 $(43)$12 
(1)    Includes net realized and unrealized gains and losses from investments in equity securities either owned directly or through ownership interests in investment funds. Unrealized gains and losses from investments that are directly owned are determined at the end of the reporting period, while gains and losses from ownership interests in investment funds are accounted for on a one quarter lag.
v3.25.2
Earnings Per Share (Tables)
 6 Months Ended
Jun. 30, 2025
Earnings Per Share [Abstract]  
Schedule of Calculations of Earnings Per Share
The calculations of earnings per share are as follows:
 Three Months Ended
June 30,		Six Months Ended
June 30,
($ and shares in millions except per share amounts)2025202420252024
Net Income Attributable to Merck & Co., Inc.
$4,427 $5,455 $9,506 $10,217 
Average common shares outstanding2,510 2,534 2,516 2,534 
Common shares issuable (1)
3 10 6 10 
Average common shares outstanding assuming dilution 2,513 2,544 2,522 2,544 
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders
$1.76 $2.15 $3.78 $4.03 
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders
$1.76 $2.14 $3.77 $4.02 
(1)    Issuable primarily under share-based compensation plans.
v3.25.2
Other Comprehensive Income (Loss) (Tables)
 6 Months Ended
Jun. 30, 2025
Equity [Abstract]  
Schedule of Changes in AOCI by Component
Changes in each component of other comprehensive income (loss) are as follows:
Three Months Ended June 30,
($ in millions)DerivativesEmployee
Benefit
Plans		Foreign Currency
Translation
Adjustment		Accumulated Other
Comprehensive
Loss
Balance April 1, 2024, net of taxes
$106 $(2,798)$(2,582)$(5,274)
Other comprehensive income (loss) before reclassification adjustments, pretax139 1 (157)(17)
Tax(29)2 (7)(34)
Other comprehensive income (loss) before reclassification adjustments, net of taxes110 3 (164)(51)
Reclassification adjustments, pretax(55)
(1)
(15)
(2)
20 (50)
Tax12 2 — 14 
Reclassification adjustments, net of taxes(43)

(13)

20 (36)
Other comprehensive income (loss), net of taxes67 (10)(144)(87)
Balance June 30, 2024, net of taxes
$173 $(2,808)$(2,726)$(5,361)
Balance April 1, 2025, net of taxes
$25 $(2,345)$(2,645)$(4,965)
Other comprehensive income (loss) before reclassification adjustments, pretax(542)(1)134 (409)
Tax114 (1)(172)(59)
Other comprehensive income (loss) before reclassification adjustments, net of taxes(428)(2)(38)(468)
Reclassification adjustments, pretax23 
(1)
(8)
(2)
— 15 
Tax(5)2 — (3)
Reclassification adjustments, net of taxes18 

(6)

— 12 
Other comprehensive income (loss), net of taxes(410)(8)(38)(456)
Balance June 30, 2025, net of taxes
$(385)$(2,353)$(2,683)$(5,421)
Six Months Ended June 30,
($ in millions)DerivativesEmployee
Benefit
Plans		Foreign Currency
Translation
Adjustment		Accumulated Other
Comprehensive
Loss
Balance January 1, 2024, net of taxes
$(24)$(2,793)$(2,344)$(5,161)
Other comprehensive income (loss) before reclassification adjustments, pretax348 6 (382)(28)
Tax(73)(2)(20)(95)
Other comprehensive income (loss) before reclassification adjustments, net of taxes275 4 (402)(123)
Reclassification adjustments, pretax(99)
(1)
(30)
(2)
20 (109)
Tax21 11 — 32 
Reclassification adjustments, net of taxes(78)(19)20 (77)
Other comprehensive income (loss), net of taxes197 (15)(382)(200)
Balance June 30, 2024, net of taxes
$173 $(2,808)$(2,726)$(5,361)
Balance January 1, 2025, net of taxes
$242 $(2,327)$(2,860)$(4,945)
Other comprehensive income (loss) before reclassification adjustments, pretax(743)(2)334 (411)
Tax156 (1)(157)(2)
Other comprehensive income (loss) before reclassification adjustments, net of taxes(587)(3)177 (413)
Reclassification adjustments, pretax(51)
(1)
(18)
(2)
— (69)
Tax11 (5)— 6 
Reclassification adjustments, net of taxes(40)(23)— (63)
Other comprehensive income (loss), net of taxes(627)(26)177 (476)
Balance June 30, 2025, net of taxes
$(385)$(2,353)$(2,683)$(5,421)
(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 9).
v3.25.2
Segment Reporting (Tables)
 6 Months Ended
Jun. 30, 2025
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,
2025202420252024
 ($ in millions)U.S.Int’lTotalU.S.Int’lTotalU.S.Int’lTotalU.S.Int’lTotal
Pharmaceutical:
Oncology
Keytruda$4,749 $3,207 $7,956 $4,412 $2,858 $7,270 $9,057 $6,104 $15,161 $8,531 $5,686 $14,217 
Alliance revenue-Lynparza (1)
174 195 370 153 165 317 319 363 682 288 321 609 
Alliance revenue-Lenvima (1)
183 83 265 177 73 249 368 155 523 349 155 504 
Welireg138 24 162 116 10 126 261 39 300 194 17 211 
Alliance revenue-Reblozyl (2)
88 19 107 75 15 90 189 37 226 133 28 161 
Vaccines
Gardasil/Gardasil 9
545 581 1,126 536 1,941 2,478 1,082 1,371 2,453 1,024 3,702 4,727 
ProQuad/M-M-R II/Varivax
481 128 609 490 127 617 903 245 1,148 928 259 1,187 
Vaxneuvance136 93 229 99 90 189 275 184 459 260 148 408 
RotaTeq60 61 121 107 56 163 225 125 349 257 123 379 
Capvaxive
129 — 129 — — — 235 1 236 — — — 
Pneumovax 23
5 33 38 11 48 59 3 76 79 17 103 120 
Hospital Acute Care
Bridion411 50 461 351 104 455 789 113 902 680 215 895 
Prevymis115 113 228 90 98 188 217 219 436 165 197 362 
Dificid83 13 96 79 12 92 155 24 179 147 17 165 
Zerbaxa45 29 74 33 28 62 87 57 145 67 51 118 
Cardiovascular
Winrevair
323 12 336 70 — 70 591 24 615 70 — 70 
Alliance revenue-Adempas/Verquvo (3)
108 15 123 98 8 106 205 23 229 188 16 203 
Adempas— 80 80 — 72 72 — 147 147 — 142 142 
Virology
Lagevrio30 52 83 15 95 110 66 119 185 60 400 460 
Isentress/Isentress HD
48 38 86 43 46 89 99 77 176 93 107 200 
Delstrigo
14 70 83 14 45 60 29 121 150 26 89 116 
Pifeltro
25 16 41 27 12 39 57 29 86 56 25 81 
Neuroscience
Belsomra18 21 40 19 34 53 31 58 90 33 66 99 
Immunology
Simponi— — — — 172 172 — — — — 356 356 
Remicade— — — — 35 35 — — — — 74 74 
Diabetes
Januvia216 155 372 177 227 405 561 360 921 361 463 824 
Janumet68 184 251 17 208 224 133 366 498 55 420 475 
Other pharmaceutical (4)
136 450 584 190 430 618 317 997 1,313 354 899 1,252 
Total Pharmaceutical segment sales8,328 5,722 14,050 7,399 7,009 14,408 16,254 11,434 27,688 14,336 14,079 28,415 
Animal Health:
Livestock190 771 961 168 669 837 384 1,501 1,885 334 1,352 1,686 
Companion Animal309 376 685 287 358 645 617 732 1,349 595 712 1,307 
Total Animal Health segment sales499 1,147 1,646 455 1,027 1,482 1,001 2,233 3,234 929 2,064 2,993 
Total segment sales8,827 6,869 15,696 7,854 8,036 15,890 17,255 13,667 30,922 15,265 16,143 31,408 
Other (5)
9 100 110 22 200 222 104 310 413 89 390 479 
 $8,836 $6,969 $15,806 $7,876 $8,236 $16,112 $17,359 $13,977 $31,335 $15,354 $16,533 $31,887 
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 (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 $16 million and $118 million for the six months ended June 30, 2025 and 2024, respectively, as well as revenue from third-party manufacturing arrangements (including sales to Organon & Co.). Other for the six months ended June 30, 2025 and 2024 also includes $100 million and $76 million, respectively, related to upfront and milestone payments received by Merck for out-licensing arrangements.
Consolidated Sales by Geographic Area
Consolidated sales by geographic area where derived are as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
($ in millions)2025202420252024
United States$8,836 $7,876 $17,359 $15,354 
Europe, Middle East and Africa3,659 3,515 7,109 7,078 
Latin America859 858 1,651 1,655 
Asia Pacific (other than China and Japan)785 748 1,474 1,472 
Japan626 686 1,295 1,507 
China446 1,817 1,148 3,589 
Other595 612 1,299 1,232 
 $15,806 $16,112 $31,335 $31,887 
Reconciliation of Segment Profits to Income before Taxes
A reconciliation of segment profits to Income Before Taxes is as follows:
Three Months Ended June 30,Six Months Ended June 30,
2025202420252024
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
TotalPharma-ceutical
Animal
Health
TotalPharma-ceutical
Animal
Health
Total
Segment sales$14,050 $1,646 $15,696 $14,408 $1,482 $15,890 $27,688 $3,234 $30,922 $28,415 $2,993 $31,408 
Less segment costs: (1)
Cost of sales1,601 659 1,708 612 3,174 1,258 3,414 1,225 
Selling, general and administrative1,456 284 1,514 270 2,858 544 2,943 523 
Research and development (2)
— 110 — 91 — 205 — 181 
Other segment items (3)
(21)— (14)1 (70)1 (46)— 
Total segment profits$11,014 $593 $11,607 $11,200 $508 $11,708 $21,726 $1,226 $22,952 $22,104 $1,064 $23,168 
Other profits30 129 231 274 
Unallocated:
Interest income69 69 178 141 
Interest expense(305)(310)(618)(613)
Amortization(601)(614)(1,198)(1,087)
Depreciation(455)(450)(896)(902)
Research and development(3,844)(3,360)(7,321)(7,209)
Restructuring costs(560)(80)(629)(202)
Other unallocated, net(942)(1,086)(1,797)(1,895)
$4,999 $6,006 $10,902 $11,675 
(1)    The significant expense categories and amounts align with the segment level information that is regularly provided to the chief operating decision maker.
(2)    Human health-related research and development expenses incurred by Merck Research Laboratories are not allocated to segment profits as noted below.
(3)    Includes equity (income) loss from affiliates and other miscellaneous non-operating expenses.
Equity Loss from Affiliates and Depreciation Included in Segment Profits
Equity income from affiliates and depreciation included in segment profits is as follows:
Three Months Ended June 30,Six Months Ended June 30,
2025202420252024
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
TotalPharma-ceutical
Animal
Health
TotalPharma-ceutical
Animal
Health
Total
Equity income from affiliates
$29 $— $29 $29 $— $29 $86 $— $86 $77 $— $77 
Depreciation
1 62 63 1 67 68 2 122 124 2 125 127 
Property, Plant and Equipment, Net by Geographic Area
Property, plant and equipment, net, by geographic area where located is as follows:
($ in millions)
June 30, 2025December 31, 2024
United States$15,182 $14,724 
Europe, Middle East and Africa8,554 7,548 
Asia Pacific (other than China and Japan)
966 982 
China204 202 
Japan144 143 
Latin America135 133 
Other51 47 
$25,236 $23,779 
v3.25.2
Acquisitions, Research Collaborations and Licensing Agreements - Narrative (Details) - USD ($)
$ / shares in Units, $ in Millions
 1 Months Ended 3 Months Ended 6 Months Ended
Jul. 31, 2025
Mar. 31, 2025
Mar. 31, 2024
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
May 31, 2025
Dec. 31, 2024
Business Combination [Line Items]                  
Research and development       $ 4,048.0 $ 3,500.0 $ 7,669.0 $ 7,492.0    
Property, plant and equipment, net       25,236.0   $ 25,236.0     $ 23,779.0
Verona Pharma plc | Subsequent Event                  
Business Combination [Line Items]                  
Consideration transferred, asset acquisition (in dollars per depository share) $ 107                
Asset acquisition, share conversion, ordinary shares per depository shares (in shares) 8                
Consideration transferred, asset acquisition $ 10,000.0                
HRS-5346 , Jiangsu Hengrui Pharmaceuticals Co., Ltd.                  
Business Combination [Line Items]                  
Research and development       $ 200.0          
Jiangsu Hengrui Pharmaceuticals Co., Ltd.                  
Business Combination [Line Items]                  
Future contingent developmental milestone payments (up to)               $ 92.5  
Future regulatory milestone payments (up to)               177.5  
Maximum aggregate sales-based milestone payments               $ 1,500.0  
WuXi Vaccines' facility                  
Business Combination [Line Items]                  
Consideration transferred, asset acquisition   $ 437.0              
WuXi Vaccines' facility | Asset under Construction                  
Business Combination [Line Items]                  
Property, plant and equipment, net   $ 759.0              
Harpoon Therapeutics, Inc.                  
Business Combination [Line Items]                  
Asset acquisition, transaction costs     $ 56.0            
Consideration transferred, asset acquisition     $ 765.0            
Research and development             656.0    
Net assets acquired             $ 165.0    
v3.25.2
Collaborative Arrangements - AstraZeneca PLC - Narrative (Details) - USD ($)
 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Lynparza | Licenses and Other    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Finite-lived intangible assets $ 1,000,000,000.0  
Koselugo | Licenses and Other    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Finite-lived intangible assets 44,000,000  
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Sales based milestone payments 700,000,000  
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Lynparza    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Sales based milestone payments 600,000,000  
Eligible future contingent sales-based milestone payments (up to) 2,000,000,000.0  
Regulatory milestone payments   $ 245,000,000
Eligible future contingent regulatory milestone payments (up to) 0  
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Koselugo    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Sales based milestone payments $ 100,000,000  
v3.25.2
Collaborative Arrangements - AstraZeneca PLC (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Cost of sales $ 3,557 $ 3,745 $ 6,976 $ 7,285  
Selling, general and administrative 2,649 2,739 5,202 5,221  
Research and development 4,048 3,500 7,669 7,492  
Other current assets 37,065   37,065   $ 38,782
Accrued and other current liabilities 14,502   14,502   15,694
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Revenue from collaborative arrangement 413 354 769 684  
Cost of sales 86 82 169 163  
Selling, general and administrative 40 43 72 82  
Research and development 16 18 28 38  
Other current assets 411   411   424
Accrued and other current liabilities 12   12   $ 713
AstraZeneca | Alliance revenue - Lynparza | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Revenue from collaborative arrangement 370 317 682 609  
AstraZeneca | Alliance revenue - Koselugo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Revenue from collaborative arrangement $ 43 $ 37 $ 87 $ 75  
v3.25.2
Collaborative Arrangements - Eisai Co., Ltd. - Narrative (Details) - Alliance revenue - Lenvima - USD ($)
 6 Months Ended
Jun. 30, 2024
Jun. 30, 2025
Licenses and Other    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Finite-lived intangible assets   $ 321,000,000
Eisai | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Sales based milestone payments $ 125,000,000  
Eligible future contingent sales-based milestone payments (up to)   2,300,000,000
Eligible future contingent regulatory milestone payments (up to)   $ 0
v3.25.2
Collaborative Arrangements - Eisai Co., Ltd. (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Cost of sales $ 3,557 $ 3,745 $ 6,976 $ 7,285  
Selling, general and administrative 2,649 2,739 5,202 5,221  
Research and development 4,048 3,500 7,669 7,492  
Other current assets 37,065   37,065   $ 38,782
Eisai | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Revenue from collaborative arrangement 265 249 523 504  
Cost of sales 60 60 121 121  
Selling, general and administrative 35 41 66 80  
Research and development 3 $ 6 7 $ 13  
Other current assets $ 265   $ 265   $ 257
v3.25.2
Collaborative Arrangements - Bayer AG (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Sales $ 15,806,000,000 $ 16,112,000,000 $ 31,335,000,000 $ 31,887,000,000  
Cost of sales 3,557,000,000 3,745,000,000 6,976,000,000 7,285,000,000  
Selling, general and administrative 2,649,000,000 2,739,000,000 5,202,000,000 5,221,000,000  
Research and development 4,048,000,000 3,500,000,000 7,669,000,000 7,492,000,000  
Other current assets 37,065,000,000   37,065,000,000   $ 38,782,000,000
Accrued and other current liabilities 14,502,000,000   14,502,000,000   15,694,000,000
Adempas | Licenses and Other          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Finite-lived intangible assets 348,000,000   348,000,000    
Verquvo | Licenses and Other          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Finite-lived intangible assets 43,000,000   43,000,000    
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Eligible future contingent sales-based milestone payments (up to) 0   0    
Revenue from collaborative arrangement 123,000,000 106,000,000 229,000,000 203,000,000  
Sales 214,000,000 187,000,000 397,000,000 361,000,000  
Cost of sales 61,000,000 61,000,000 120,000,000 123,000,000  
Selling, general and administrative 29,000,000 26,000,000 58,000,000 59,000,000  
Research and development 20,000,000 28,000,000 43,000,000 55,000,000  
Other current assets 173,000,000   173,000,000   160,000,000
Accrued and other current liabilities 88,000,000   88,000,000   $ 82,000,000
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Adempas          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Sales 80,000,000 72,000,000 147,000,000 142,000,000  
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Verquvo          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Sales $ 11,000,000 $ 9,000,000 $ 21,000,000 $ 16,000,000  
v3.25.2
Collaborative Arrangements - Ridgeback Biotherapeutics LP (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Sales $ 15,806 $ 16,112 $ 31,335 $ 31,887  
Cost of sales 3,557 3,745 6,976 7,285  
Selling, general and administrative 2,649 2,739 5,202 5,221  
Accrued and other current liabilities 14,502   14,502   $ 15,694
Ridgeback Biotherapeutics LP | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Cost of sales 44 96 97 287  
Selling, general and administrative 14 16 28 32  
Research and development 6 7 14 2  
Accrued and other current liabilities 31   31   $ 68
Ridgeback Biotherapeutics LP | Lagevrio | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Sales $ 83 $ 110 $ 185 $ 460  
v3.25.2
Collaborative Arrangements - Daiicho Sankyo - Narrative (Details)
$ in Millions
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Aug. 31, 2024
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2024
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2024
USD ($)
Dec. 31, 2023
USD ($)
candidate
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Research and development   $ 4,048 $ 3,500 $ 7,669 $ 7,492  
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Number of antibody drug conjugates obtained right and obligations | candidate           3
Aggregate upfront payments due upon execution in collaborative arrangement           $ 4,000
Refundable upfront payments in collaborative arrangement           1,000
Maximum aggregate contingent milestone payments, per product, in collaborative arrangement           5,500
Research and development   $ 193 $ 65 $ 321 $ 133 $ 5,500
Sales based royalty percentage 5.00%         5.00%
Upfront cash payment $ 170          
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Ifinatamab Deruxtecan            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Refundable upfront payments in collaborative arrangement           $ 500
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Patritumab Deruxtecan            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Refundable upfront payments in collaborative arrangement           500
Aggregate upfront payments due upon lapse of time in collaborative arrangement           750
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Raludotatug Deruxtecan            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Aggregate upfront payments due upon lapse of time in collaborative arrangement           $ 750
Liable contracted portion of research and development expenses to incur costs for in collaborative arrangement, percentage           75.00%
Liable contracted portion of research and development expenses to incur costs for in collaborative arrangement           $ 2,000
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Patritumab Deruxtecan and Ralduotatug Deruxtecan            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Aggregate upfront payments due upon lapse of time in collaborative arrangement           $ 1,500
v3.25.2
Collaborative Arrangements - Daiicho Sankyo (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2023
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Selling, general and administrative $ 2,649 $ 2,739 $ 5,202 $ 5,221    
Research and development 4,048 3,500 7,669 7,492    
Other current assets 9,996   9,996     $ 8,706
Accrued and other current liabilities 14,502   14,502     15,694
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Selling, general and administrative 4 14 13 16    
Research and development 193 $ 65 321 $ 133 $ 5,500  
Other current assets 21   21     8
Accrued and other current liabilities $ 850   $ 850     $ 817
v3.25.2
Collaborative Arrangements - Moderna, Inc. - Narrative (Details)
$ in Millions
Jun. 30, 2025
USD ($)
Moderna, Inc. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]  
Capitalization of shared costs $ 232
v3.25.2
Collaborative Arrangements - Moderna, Inc. (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Selling, general and administrative $ 2,649 $ 2,739 $ 5,202 $ 5,221  
Research and development 4,048 3,500 7,669 7,492  
Accrued and other current liabilities 14,502   14,502   $ 15,694
Moderna, Inc. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Selling, general and administrative 6 4 12 6  
Research and development 90 $ 93 176 $ 162  
Accrued and other current liabilities $ 22   $ 22   $ 57
v3.25.2
Collaborative Arrangements - Bristol Meyers Squibb Company - Narrative (Details) - Bristol Myers Squibb Company - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Licensing Agreements        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]        
Royalty rate, deduction     0.50  
Licensing Agreements | Alliance Revenue - Reblozyl        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]        
Eligible future contingent sales-based milestone payments (up to) $ 80   $ 80  
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]        
Revenue from collaborative arrangement $ 107 $ 90 $ 226 $ 161
Minimum | Licensing Agreements        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]        
Royalty rate     20.00%  
Maximum | Licensing Agreements        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]        
Royalty rate     24.00%  
v3.25.2
Restructuring - Narrative (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs $ 779   $ 884  
Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Expected restructuring and related cost 3,000   $ 3,000  
Estimate of cumulative pre tax costs that will be cash     60.00%  
Total pretax restructuring costs 649   $ 649  
Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Expected restructuring and related cost 4,000   $ 4,000  
Estimate of cumulative pre tax costs that will be noncash     60.00%  
Total pretax restructuring costs 130 $ 177 $ 235 $ 422
Cumulative costs since program inception $ 1,300   $ 1,300  
v3.25.2
Restructuring - Charges Activities by Type of Cost (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs $ 779   $ 884  
Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 649   649  
Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 130 $ 177 235 $ 422
Accelerated Depreciation        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 55   96  
Accelerated Depreciation | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 55 66 96 131
Separation Costs        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 487   488  
Separation Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 481   481  
Separation Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 6 19 7 111
Other Exit Costs        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 237   300  
Other Exit Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 168   168  
Other Exit Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 69 92 132 180
Cost of sales | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 100   100  
Cost of sales | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 65 66 101 182
Cost of sales | Accelerated Depreciation | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Cost of sales | Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 55 66 96 131
Cost of sales | Separation Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Cost of sales | Separation Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0 0 0 0
Cost of sales | Other Exit Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 100   100  
Cost of sales | Other Exit Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 10 0 5 51
Selling, general and administrative | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 1 31 1 36
Selling, general and administrative | Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0 0 0 0
Selling, general and administrative | Separation Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0 0 0 0
Selling, general and administrative | Other Exit Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 1 31 1 36
Research and development | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 53   53  
Research and development | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs   0   2
Research and development | Accelerated Depreciation | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Research and development | Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs   0   0
Research and development | Separation Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Research and development | Separation Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs   0   0
Research and development | Other Exit Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 53   53  
Research and development | Other Exit Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs   0   2
Restructuring costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 496   496  
Restructuring costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 64 80 133 202
Restructuring costs | Accelerated Depreciation | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Restructuring costs | Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0 0 0 0
Restructuring costs | Separation Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 481   481  
Restructuring costs | Separation Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 6 19 7 111
Restructuring costs | Other Exit Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 15   15  
Restructuring costs | Other Exit Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs $ 58 $ 61 $ 126 $ 91
v3.25.2
Restructuring - Activities by Program (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Restructuring Reserve [Roll Forward]        
Expenses $ 779   $ 884  
Restructuring Program, 2025        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 649   649  
Non-cash activity     (53)  
Restructuring reserve, ending balance 596   596  
Restructuring Program, 2024        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     564  
Expenses 130 $ 177 235 $ 422
(Payments) receipts, net     (149)  
Non-cash activity     (102)  
Restructuring reserve, ending balance 548   548  
Accelerated Depreciation        
Restructuring Reserve [Roll Forward]        
Expenses 55   96  
Accelerated Depreciation | Restructuring Program, 2025        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 0   0  
Non-cash activity     0  
Restructuring reserve, ending balance 0   0  
Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 55 66 96 131
(Payments) receipts, net     0  
Non-cash activity     (96)  
Restructuring reserve, ending balance 0   0  
Separation Costs        
Restructuring Reserve [Roll Forward]        
Expenses 487   488  
Separation Costs | Restructuring Program, 2025        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 481   481  
Non-cash activity     0  
Restructuring reserve, ending balance 481   481  
Separation Costs | Restructuring Program, 2024        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     564  
Expenses 6 19 7 111
(Payments) receipts, net     (23)  
Non-cash activity     0  
Restructuring reserve, ending balance 548   548  
Other Exit Costs        
Restructuring Reserve [Roll Forward]        
Expenses 237   300  
Other Exit Costs | Restructuring Program, 2025        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 168   168  
Non-cash activity     (53)  
Restructuring reserve, ending balance 115   115  
Other Exit Costs | Restructuring Program, 2024        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 69 $ 92 132 $ 180
(Payments) receipts, net     (126)  
Non-cash activity     (6)  
Restructuring reserve, ending balance $ 0   $ 0  
v3.25.2
Financial Instruments - Narrative (Details)
$ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2025
USD ($)
interest_rate_swap
Jun. 30, 2024
USD ($)
Jun. 30, 2025
USD ($)
interest_rate_swap
Jun. 30, 2024
USD ($)
Dec. 31, 2024
USD ($)
Aug. 31, 2025
USD ($)
Derivative [Line Items]            
Pretax net unrealized loss on derivatives maturing within the next 12 months estimated to be reclassified from AOCI to sales $ 473   $ 473      
Equity investments without readily determinable fair values 870 $ 936 870 $ 936    
Unrealized gains recognized on investments in equity securities without readily determinable fair value       61    
Unrealized losses recognized on investments in equity securities without readily determinable fair values     33 5    
Cumulative unrealized gains on investments 307   307      
Cumulative unrealized losses on investments 131   131      
Loss (income) from investments in equity securities, net (100) (56) (189) (200)    
Fair value of loans payable and long-term debt, including current portion 31,300   31,300   $ 32,600  
Debt, carrying amount 35,400   35,400   37,100  
Factored accounts receivable     1,600   2,100  
Cash collateral received from counterparties 4   4   165  
Cash collateral advanced to counterparties 97   97   0  
Derivative, notional amount 44,694   44,694   38,560  
Accounts Receivable Factoring Collections            
Derivative [Line Items]            
Restricted cash 43   43   55  
Level 2            
Derivative [Line Items]            
Cash equivalents 7,300   7,300   12,300  
Equity Funds            
Derivative [Line Items]            
Publicly traded equity securities 221 278 221 278    
Loss (income) from investments in equity securities, net $ 27 $ (7) $ 50 $ (5)    
Interest rate swap contracts            
Derivative [Line Items]            
Number of Interest Rate Swaps Held | interest_rate_swap 7   7      
Interest rate swap contracts | Subsequent Event            
Derivative [Line Items]            
Derivative, notional amount           $ 250
Derivatives Designated as Hedging Instruments            
Derivative [Line Items]            
Derivative, notional amount $ 15,403   $ 15,403   12,465  
Derivatives Not Designated as Hedging Instruments            
Derivative [Line Items]            
Derivative, notional amount $ 29,291   $ 29,291   $ 26,095  
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      
v3.25.2
Financial Instruments - Effect of Net Investment Hedges (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Foreign exchange contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income $ 38 $ 5 $ 65 $ 3
Foreign exchange contracts | Other (income) expense, net        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Pretax Gain Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing 5 1 8 1
Euro-denominated notes        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income 411 (34) 541 (96)
Euro-denominated notes | Other (income) expense, net        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Pretax Gain Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing $ 0 $ 0 $ 0 $ 0
v3.25.2
Financial Instruments - Summary of Interest Rate Swaps Held (Details)
Jun. 30, 2025
USD ($)
interest_rate_swap
Dec. 31, 2024
USD ($)
Derivative [Line Items]    
U.S dollar notional amount $ 44,694,000,000 $ 38,560,000,000
4.50% note due 2033 | 4.50% note due 2033    
Derivative [Line Items]    
Stated interest rate 4.50%  
5.00% note due 2053 | 5.00% note due 2053    
Derivative [Line Items]    
Stated interest rate 5.00%  
Interest rate swap contracts    
Derivative [Line Items]    
Number of Interest Rate Swaps Held | interest_rate_swap 7  
Interest rate swap contracts | 4.50% note due 2033    
Derivative [Line Items]    
Par Value of Debt $ 1,500,000,000  
Number of Interest Rate Swaps Held | interest_rate_swap 6  
U.S dollar notional amount $ 1,500,000,000  
Interest rate swap contracts | 5.00% note due 2053    
Derivative [Line Items]    
Par Value of Debt $ 1,500,000,000  
Number of Interest Rate Swaps Held | interest_rate_swap 1  
U.S dollar notional amount $ 250,000,000  
v3.25.2
Financial Instruments - Amounts Recorded on Balance Sheet Related to Fair Value Hedges (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Hedged Liability, Statement of Financial Position [Extensible Enumeration] Long-Term Debt Long-Term Debt
Carrying Amount of Hedged Liabilities $ 1,814 $ 1,509
Cumulative Amount of Fair Value Hedging Adjustment Increase Included in the Carrying Amount $ 75 $ 17
v3.25.2
Financial Instruments - Fair Value of Derivatives Segregated between those Derivatives that are Designated as Hedging Instruments and those that are Not Designated as Hedging Instruments (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Derivatives, Fair Value [Line Items]    
Fair value of derivative, asset $ 546 $ 729
Fair value of derivative, liability 855 345
U.S dollar notional amount 44,694 38,560
Derivatives Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Fair value of derivative, asset 128 406
Fair value of derivative, liability 449 2
U.S dollar notional amount 15,403 12,465
Derivatives Not Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Fair value of derivative, asset 418 323
Fair value of derivative, liability 406 343
U.S dollar notional amount $ 29,291 $ 26,095
Interest rate swap contracts | Derivatives Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other Assets Other Assets
Fair value of derivative, asset $ 76 $ 17
Derivative asset, notional amount $ 1,750 $ 1,500
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other Assets    
Derivatives, Fair Value [Line Items]    
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other Assets Other Assets
Fair value of derivative, asset $ 29 $ 66
Derivative asset, notional amount $ 2,076 $ 2,125
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other current assets    
Derivatives, Fair Value [Line Items]    
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other current assets Other current assets
Fair value of derivative, asset $ 23 $ 323
Derivative asset, notional amount $ 2,289 $ 8,662
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Accrued and other current liabilities    
Derivatives, Fair Value [Line Items]    
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Accrued and other current liabilities Accrued and other current liabilities
Fair value of derivative, liability $ 433 $ 1
Derivative liability, notional amount $ 8,732 $ 162
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other Noncurrent Liabilities    
Derivatives, Fair Value [Line Items]    
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Other Noncurrent Liabilities Other Noncurrent Liabilities
Fair value of derivative, liability $ 16 $ 1
Derivative liability, notional amount $ 556 $ 16
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments | Other Assets    
Derivatives, Fair Value [Line Items]    
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other Assets Other Assets
Fair value of derivative, asset $ 1 $ 0
Derivative asset, notional amount $ 475 $ 0
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments | Other current assets    
Derivatives, Fair Value [Line Items]    
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other current assets Other current assets
Fair value of derivative, asset $ 417 $ 323
Derivative asset, notional amount $ 15,819 $ 12,544
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments | Accrued and other current liabilities    
Derivatives, Fair Value [Line Items]    
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Accrued and other current liabilities Accrued and other current liabilities
Fair value of derivative, liability $ 405 $ 343
Derivative liability, notional amount $ 12,522 $ 13,551
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments | Other Noncurrent Liabilities    
Derivatives, Fair Value [Line Items]    
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Other Noncurrent Liabilities Other Noncurrent Liabilities
Fair value of derivative, liability $ 1 $ 0
Derivative liability, notional amount $ 475 $ 0
v3.25.2
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, 2025
Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Gross amounts recognized in the consolidated balance sheet, asset $ 546 $ 729
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, asset (445) (299)
Cash collateral received, asset (4) (165)
Net amounts, asset 97 265
Gross amounts recognized in the consolidated balance sheet, liability 855 345
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, liability (445) (299)
Cash collateral received, liability (97) 0
Net amounts, liability $ 313 $ 46
v3.25.2
Financial Instruments - Location and Amount of Pretax (Gains) Losses of Derivatives (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Derivative Instruments, Gain (Loss) [Line Items]        
Sales $ 15,806 $ 16,112 $ 31,335 $ 31,887
Other (income) expense, net (7) 42 (43) 12
Other comprehensive income (loss) (456) (87) (476) (200)
Interest rate swap contracts | Other (income) expense, net        
Derivative Instruments, Gain (Loss) [Line Items]        
Hedged items 20 4 58 (26)
Derivatives designated as hedging instruments (19) (4) (58) 27
Foreign exchange contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of (loss) gain recognized in OCI on derivatives (542) 139 (743) 348
(Decrease) increase in Sales as a result of AOCL reclassifications 23 (54) (50) (98)
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 $ (23) $ 54 50 98
Interest rate contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of (loss) gain recognized in OCI on derivatives     (1) (1)
Amount of gain recognized in Other (income) expense, net on derivatives     $ (1) $ (1)
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]     Other (income) expense, net Other (income) expense, net
v3.25.2
Financial Instruments - Income Statement Effects on Derivatives Not Designated as Hedging Instruments (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Currency Swap | Other (income) expense, net        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Derivative Pretax (Gain) Loss Recognized in Income $ (237) $ 9 $ (256) $ 75
Foreign Exchange Future | Sales        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Derivative Pretax (Gain) Loss Recognized in Income $ 17 $ (10) $ 34 $ (20)
v3.25.2
Financial Instruments - Information on Available-for-sale Investments (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]          
Amortized Cost $ 707   $ 707   $ 536
Debt securities, unrealized gains 0   0   0
Debt securities, unrealized losses 0   0   0
Debt securities, fair value 707   707   536
Publicly traded equity securities, fair value 1,181   1,181   920
Total debt and publicly traded equity securities, fair value 1,888   1,888   1,456
Unrealized net gains (losses) 147 $ (8) 262 $ 125  
Commercial paper          
Debt Securities, Available-for-sale [Line Items]          
Amortized Cost 416   416   348
Debt securities, unrealized gains 0   0   0
Debt securities, unrealized losses 0   0   0
Debt securities, fair value 416   416   348
U.S. government and agency securities          
Debt Securities, Available-for-sale [Line Items]          
Amortized Cost 290   290   188
Debt securities, unrealized gains 0   0   0
Debt securities, unrealized losses 0   0   0
Debt securities, fair value 290   290   188
Foreign government bonds          
Debt Securities, Available-for-sale [Line Items]          
Amortized Cost 1   1   0
Debt securities, unrealized gains 0   0   0
Debt securities, unrealized losses 0   0   0
Debt securities, fair value $ 1   $ 1   $ 0
v3.25.2
Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Jun. 30, 2024
Dec. 31, 2023
Assets        
Commercial paper $ 707 $ 536    
Publicly traded equity securities 1,181 920    
Other Assets 17,664 16,044    
Fair value of derivative, asset 546 729    
Liabilities        
Contingent consideration 0 193 $ 225 $ 354
Fair value of derivative, liability 855 345    
Commercial paper        
Assets        
Commercial paper 416 348    
U.S. government and agency securities        
Assets        
Commercial paper 290 188    
Foreign government bonds        
Assets        
Commercial paper 1 0    
Fair Value, Measurements, Recurring        
Assets        
Investments 1,389 910    
Other Assets 499 546    
Fair value of derivative, asset 546 729    
Total assets 2,434 2,185    
Liabilities        
Contingent consideration 0 193    
Fair value of derivative, liability 855 345    
Total liabilities 855 538    
Fair Value, Measurements, Recurring | Foreign exchange contracts        
Assets        
Fair value of derivative, asset 411 499    
Liabilities        
Fair value of derivative, liability 801 338    
Fair Value, Measurements, Recurring | Currency options        
Assets        
Fair value of derivative, asset 59 213    
Liabilities        
Fair value of derivative, liability 54 7    
Fair Value, Measurements, Recurring | Interest rate swap contracts        
Assets        
Fair value of derivative, asset 76 17    
Fair Value, Measurements, Recurring | Level 1        
Assets        
Investments 774 463    
Other Assets 499 546    
Fair value of derivative, asset 0 0    
Total assets 1,273 1,009    
Liabilities        
Contingent consideration 0 0    
Fair value of derivative, liability 0 0    
Total liabilities 0 0    
Fair Value, Measurements, Recurring | Level 1 | Foreign exchange contracts        
Assets        
Fair value of derivative, asset 0 0    
Liabilities        
Fair value of derivative, liability 0 0    
Fair Value, Measurements, Recurring | Level 1 | Currency options        
Assets        
Fair value of derivative, asset 0 0    
Liabilities        
Fair value of derivative, liability 0 0    
Fair Value, Measurements, Recurring | Level 1 | Interest rate swap contracts        
Assets        
Fair value of derivative, asset 0 0    
Fair Value, Measurements, Recurring | Level 2        
Assets        
Investments 615 447    
Other Assets 0 0    
Fair value of derivative, asset 546 729    
Total assets 1,161 1,176    
Liabilities        
Contingent consideration 0 0    
Fair value of derivative, liability 855 345    
Total liabilities 855 345    
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts        
Assets        
Fair value of derivative, asset 411 499    
Liabilities        
Fair value of derivative, liability 801 338    
Fair Value, Measurements, Recurring | Level 2 | Currency options        
Assets        
Fair value of derivative, asset 59 213    
Liabilities        
Fair value of derivative, liability 54 7    
Fair Value, Measurements, Recurring | Level 2 | Interest rate swap contracts        
Assets        
Fair value of derivative, asset 76 17    
Fair Value, Measurements, Recurring | Level 3        
Assets        
Investments 0 0    
Other Assets 0 0    
Fair value of derivative, asset 0 0    
Total assets 0 0    
Liabilities        
Contingent consideration 0 193    
Fair value of derivative, liability 0 0    
Total liabilities 0 193    
Fair Value, Measurements, Recurring | Level 3 | Foreign exchange contracts        
Assets        
Fair value of derivative, asset 0 0    
Liabilities        
Fair value of derivative, liability 0 0    
Fair Value, Measurements, Recurring | Level 3 | Currency options        
Assets        
Fair value of derivative, asset 0 0    
Liabilities        
Fair value of derivative, liability 0 0    
Fair Value, Measurements, Recurring | Level 3 | Interest rate swap contracts        
Assets        
Fair value of derivative, asset 0 0    
Fair Value, Measurements, Recurring | Commercial paper        
Assets        
Commercial paper 416 348    
Fair Value, Measurements, Recurring | Commercial paper | Level 1        
Assets        
Commercial paper 0 0    
Fair Value, Measurements, Recurring | Commercial paper | Level 2        
Assets        
Commercial paper 416 348    
Fair Value, Measurements, Recurring | Commercial paper | Level 3        
Assets        
Commercial paper 0 0    
Fair Value, Measurements, Recurring | U.S. government and agency securities        
Assets        
U.S. government and agency securities 198 99    
U.S. government and agency securities 92 89    
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 1        
Assets        
U.S. government and agency securities 0 0    
U.S. government and agency securities 92 89    
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 2        
Assets        
U.S. government and agency securities 198 99    
U.S. government and agency securities 0 0    
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 3        
Assets        
U.S. government and agency securities 0 0    
U.S. government and agency securities 0 0    
Fair Value, Measurements, Recurring | Publicly traded equity securities        
Assets        
Publicly traded equity securities 774 463    
Publicly traded equity securities 407 457    
Fair Value, Measurements, Recurring | Publicly traded equity securities | Level 1        
Assets        
Publicly traded equity securities 774 463    
Publicly traded equity securities 407 457    
Liabilities        
Securities subject to contractual sale restrictions   81    
Fair Value, Measurements, Recurring | Publicly traded equity securities | Level 2        
Assets        
Publicly traded equity securities 0 0    
Publicly traded equity securities 0 0    
Fair Value, Measurements, Recurring | Publicly traded equity securities | Level 3        
Assets        
Publicly traded equity securities 0 0    
Publicly traded equity securities 0 0    
Fair Value, Measurements, Recurring | Foreign government bonds        
Assets        
U.S. government and agency securities 1 0    
Fair Value, Measurements, Recurring | Foreign government bonds | Level 1        
Assets        
U.S. government and agency securities 0 0    
Fair Value, Measurements, Recurring | Foreign government bonds | Level 2        
Assets        
U.S. government and agency securities 1 0    
Fair Value, Measurements, Recurring | Foreign government bonds | Level 3        
Assets        
U.S. government and agency securities $ 0 $ 0    
v3.25.2
Financial Instruments - Information About Changes in Liabilities for Contingent Consideration (Details) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning balance $ 193 $ 354
Changes in estimated fair value (52) (3)
Payments (141) (126)
Fair value, ending balance 0 $ 225
Zerbaxa    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Changes in estimated fair value (45)  
Payments $ (25)  
v3.25.2
Inventories - Schedule of Inventories (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Inventory Disclosure [Abstract]    
Finished goods $ 2,142 $ 2,022
Raw materials and work in process 9,888 8,831
Supplies 312 289
Total 12,342 11,142
Decrease to LIFO cost (859) (840)
Total current and noncurrent inventories 11,483 10,302
Recognized as:    
Inventories 6,601 6,109
Other Assets $ 4,882 $ 4,193
v3.25.2
Inventories - Narrative (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Inventory [Line Items]    
Inventories classified in other assets $ 4,882 $ 4,193
Inventories Not Expected to be Sold Within One Year    
Inventory [Line Items]    
Inventories classified in other assets 4,300 3,800
Inventories Produced in Preparation for Product Launches    
Inventory [Line Items]    
Inventories classified in other assets $ 572 $ 412
v3.25.2
Contingencies (Details)
$ in Millions
 1 Months Ended 6 Months Ended
Apr. 24, 2025
patent
Mar. 13, 2025
Apr. 13, 2023
patent
Dec. 31, 2023
case
Jun. 30, 2023
Jun. 30, 2025
USD ($)
company
case
proceeding
Jun. 02, 2025
patent
May 01, 2025
plaintiff
Apr. 07, 2025
Mar. 21, 2025
plaintiff
Mar. 11, 2025
case
Dec. 31, 2024
USD ($)
Loss Contingencies [Line Items]                        
Number of plaintiffs in complaint | plaintiff               6,000,000   7,000,000    
Loss contingency, joint stipulation response period                 14 days      
Legal Defense Costs                        
Loss Contingencies [Line Items]                        
Legal defense costs reserve | $           $ 255           $ 225
Pending Litigation | Patents - PGR Petition                        
Loss Contingencies [Line Items]                        
Loss contingency, number of patents allegedly infringed 12                      
Dr. Scholl's | U.S. | Pending Litigation                        
Loss Contingencies [Line Items]                        
Loss contingency, pending claims | case           575            
Gardasil/Gardasil 9 | U.S. | Pending Litigation                        
Loss Contingencies [Line Items]                        
Loss contingency, pending claims | case           125            
Gardasil/Gardasil 9 | U.S. | Motion for Summary Judgement Granted                        
Loss Contingencies [Line Items]                        
Loss contingency, pending claims | case                     16  
Gardasil/Gardasil 9 | Non-US | Pending Litigation                        
Loss Contingencies [Line Items]                        
Loss contingency, pending claims | case           15            
Zetia | U.S. | Pending Litigation                        
Loss Contingencies [Line Items]                        
Loss contingency, number of cases remanded | case       4,000,000                
Bridion | Patents                        
Loss Contingencies [Line Items]                        
Loss contingency, claims settled, number of companies | company           5            
Bridion | Settled Litigation | Patents                        
Loss Contingencies [Line Items]                        
Patent extension, term   5 years     5 years              
Pediatric exclusivity, term   6 months                    
Januvia, Janumet, Janumet XR | Settled Litigation                        
Loss Contingencies [Line Items]                        
Loss contingency, companies settled with, minimum number | company           24            
Keytruda | Pending Litigation | Patents                        
Loss Contingencies [Line Items]                        
Loss contingency, pending claims | proceeding           8            
Loss contingency, number of patents allegedly infringed     9                  
Subcutaneous Pembrolizumab | Pending Litigation | Patents                        
Loss Contingencies [Line Items]                        
Loss contingency, pending claims             10          
Loss contingency, number of patents allegedly infringed 15                      
Subcutaneous Pembrolizumab | Pending Litigation | Patents - PGR Petition                        
Loss Contingencies [Line Items]                        
Loss contingency, pending claims             3          
Subcutaneous Pembrolizumab | Pending Litigation | PGR Petition Process, Ineligible to be Challenged                        
Loss Contingencies [Line Items]                        
Loss contingency, pending claims 3                      
v3.25.2
Equity (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Common stock, beginning balance (in shares)     3,577,103,522  
Equity, beginning balance $ 48,400 $ 40,424 $ 46,372 $ 37,635
Treasury stock, beginning balance (in shares)     1,049,466,187  
Net income attributable to Merck & Co., Inc. 4,427 5,455 $ 9,506 10,217
Other comprehensive loss, net of taxes (456) (87) (476) (200)
Cash dividends declared on common stock (2,047) (1,965) (4,098) (3,925)
Treasury stock shares purchased (1,345) (251) (2,509) (373)
Share-based compensation plans and other 80 66 257 283
Net income attributable to noncontrolling interests $ 1 6 $ 8 11
Common stock, ending balance (in shares) 3,577,103,522   3,577,103,522  
Equity, ending balance $ 49,060 $ 43,648 $ 49,060 $ 43,648
Treasury stock, ending balance (in shares) 1,073,963,194   1,073,963,194  
Cash dividends declared on common stock (in dollars per share) $ 0.81 $ 0.77 $ 1.62 $ 1.54
  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 44,816 44,598 44,704 44,509
Share-based compensation plans and other (172) (236) (60) (147)
Equity, ending balance 44,644 44,362 44,644 44,362
Retained Earnings        
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Equity, beginning balance 66,097 56,697 63,069 53,895
Net income attributable to Merck & Co., Inc. 4,427 5,455 9,506 10,217
Cash dividends declared on common stock (2,047) (1,965) (4,098) (3,925)
Equity, ending balance 68,477 60,187 68,477 60,187
Accumulated Other Comprehensive Loss        
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Equity, beginning balance (4,965) (5,274) (4,945) (5,161)
Other comprehensive loss, net of taxes (456) (87) (476) (200)
Equity, ending balance (5,421) (5,361) (5,421) (5,361)
 Treasury Stock        
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Equity, beginning balance $ (59,401) $ (57,445) $ (58,303) $ (57,450)
Treasury stock, beginning balance (in shares) 1,061,000,000 1,044,000,000 1,049,000,000 1,045,000,000
Treasury stock shares purchased (in shares) 17,000,000 2,000,000 29,000,000 3,000,000
Treasury stock shares purchased $ (1,345) $ (251) $ (2,509) $ (373)
Share-based compensation plans and other $ 251 $ 302 $ 317 $ 429
Share-based compensation plans and other (in shares) (4,000,000) (5,000,000) (4,000,000) (7,000,000)
Equity, ending balance $ (60,495) $ (57,394) $ (60,495) $ (57,394)
Treasury stock, ending balance (in shares) 1,074,000,000 1,041,000,000 1,074,000,000 1,041,000,000
Non- controlling Interests        
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Equity, beginning balance $ 65 $ 60 $ 59 $ 54
Share-based compensation plans and other 1     1
Net income attributable to noncontrolling interests 1 6 8 11
Equity, ending balance $ 67 $ 66 $ 67 $ 66
v3.25.2
Pension and Other Postretirement Benefit Plans - Net Benefit Costs (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Other Postretirement Benefit Plans        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 9 $ 8 $ 19 $ 15
Interest cost 16 14 31 28
Expected return on plan assets (13) (20) (26) (40)
Amortization of unrecognized prior service credit (10) (11) (20) (21)
Net (gain) loss amortization (10) (12) (20) (24)
Net periodic benefit cost (8) (21) (16) (42)
U.S. | Pension Plans        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 90 86 180 173
Interest cost 141 134 282 269
Expected return on plan assets (210) (207) (420) (417)
Amortization of unrecognized prior service credit 0 0 0 0
Net (gain) loss amortization 13 10 25 20
Termination benefits 0 0 0 4
Net periodic benefit cost 34 23 67 49
International | Pension Plans        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 60 60 114 122
Interest cost 75 73 146 147
Expected return on plan assets (152) (137) (295) (278)
Amortization of unrecognized prior service credit (4) (3) (8) (6)
Net (gain) loss amortization 2 1 5 3
Termination benefits 0 0 0 0
Net periodic benefit cost $ (19) $ (6) $ (38) $ (12)
v3.25.2
Other (Income) Expense, Net - Schedule of Other (Income) Expense, Net (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Other Income and Expenses [Abstract]        
Interest income $ (69) $ (69) $ (178) $ (141)
Interest expense 305 310 618 613
Exchange losses 78 60 167 144
Loss (income) from investments in equity securities, net (100) (56) (189) (200)
Net periodic defined benefit plan (credit) cost other than service cost (152) (159) (300) (319)
Other, net (69) (44) (161) (85)
Other (income) expense, net $ (7) $ 42 $ (43) $ 12
v3.25.2
Other (Income) Expense, Net - Narrative (Details) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Other Income and Expenses [Abstract]    
Interest paid $ 616 $ 581
v3.25.2
Income Taxes (Details) - USD ($)
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Apr. 30, 2025
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2025
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]            
Effective income tax rate   11.40% 9.10% 12.70% 12.40%  
Effective income tax rate reconciliation, tax contingency, favorable impact, percent   2.90% 4.30% 1.40% 2.20%  
Unrecognized tax benefits   $ 146,000,000 $ 259,000,000 $ 146,000,000 $ 259,000,000  
Income tax rate, unfavorable discrete impact         0.70%  
Tax benefit resulting from acquisition charge         $ 0  
Internal Revenue Service (IRS)            
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]            
Income tax examination, estimate of possible loss $ 1,300,000,000          
Internal Revenue Service (IRS) | Penalties            
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]            
Income tax examination, estimate of possible loss $ 260,000,000          
Forecast            
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]            
Global minimum tax impact on effective tax rate, percentage increase           2.00%
v3.25.2
Earnings Per Share - Calculations of Earnings Per Share (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Earnings Per Share [Abstract]        
Net Income Attributable to Merck & Co., Inc., basic $ 4,427 $ 5,455 $ 9,506 $ 10,217
Net Income Attributable to Merck & Co., Inc., diluted $ 4,427 $ 5,455 $ 9,506 $ 10,217
Average common shares outstanding (in shares) 2,510 2,534 2,516 2,534
Common shares issuable (in shares) 3 10 6 10
Average common shares outstanding assuming dilution (in shares) 2,513 2,544 2,522 2,544
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 1.76 $ 2.15 $ 3.78 $ 4.03
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 1.76 $ 2.14 $ 3.77 $ 4.02
v3.25.2
Earnings Per Share - Narrative (Details) - shares
shares in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Earnings Per Share [Abstract]        
Antidilutive shares (in shares) 19 7 12 5
v3.25.2
Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Equity, beginning balance $ 48,400 $ 40,424 $ 46,372 $ 37,635
Other comprehensive income (loss), net of taxes (456) (87) (476) (200)
Equity, ending balance 49,060 43,648 49,060 43,648
Accumulated Other Comprehensive Loss        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Equity, beginning balance (4,965) (5,274) (4,945) (5,161)
Other comprehensive income (loss) before reclassification adjustments, pretax (409) (17) (411) (28)
Tax (59) (34) (2) (95)
Other comprehensive income (loss) before reclassification adjustments, net of taxes (468) (51) (413) (123)
Reclassification adjustments, pretax 15 (50) (69) (109)
Tax (3) 14 6 32
Reclassification adjustments, net of taxes 12 (36) (63) (77)
Other comprehensive income (loss), net of taxes (456) (87) (476) (200)
Equity, ending balance (5,421) (5,361) (5,421) (5,361)
Derivatives        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Equity, beginning balance 25 106 242 (24)
Other comprehensive income (loss) before reclassification adjustments, pretax (542) 139 (743) 348
Tax 114 (29) 156 (73)
Other comprehensive income (loss) before reclassification adjustments, net of taxes (428) 110 (587) 275
Reclassification adjustments, pretax 23 (55) (51) (99)
Tax (5) 12 11 21
Reclassification adjustments, net of taxes 18 (43) (40) (78)
Other comprehensive income (loss), net of taxes (410) 67 (627) 197
Equity, ending balance (385) 173 (385) 173
Employee Benefit Plans        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Equity, beginning balance (2,345) (2,798) (2,327) (2,793)
Other comprehensive income (loss) before reclassification adjustments, pretax (1) 1 (2) 6
Tax (1) 2 (1) (2)
Other comprehensive income (loss) before reclassification adjustments, net of taxes (2) 3 (3) 4
Reclassification adjustments, pretax (8) (15) (18) (30)
Tax 2 2 (5) 11
Reclassification adjustments, net of taxes (6) (13) (23) (19)
Other comprehensive income (loss), net of taxes (8) (10) (26) (15)
Equity, ending balance (2,353) (2,808) (2,353) (2,808)
Foreign Currency Translation Adjustment        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Equity, beginning balance (2,645) (2,582) (2,860) (2,344)
Other comprehensive income (loss) before reclassification adjustments, pretax 134 (157) 334 (382)
Tax (172) (7) (157) (20)
Other comprehensive income (loss) before reclassification adjustments, net of taxes (38) (164) 177 (402)
Reclassification adjustments, pretax 0 20 0 20
Tax 0 0 0 0
Reclassification adjustments, net of taxes 0 20 0 20
Other comprehensive income (loss), net of taxes (38) (144) 177 (382)
Equity, ending balance $ (2,683) $ (2,726) $ (2,683) $ (2,726)
v3.25.2
Segment Reporting - Narrative (Details)
$ in Billions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
USD ($)
Jun. 30, 2024
USD ($)
Jun. 30, 2025
USD ($)
segment
Jun. 30, 2024
USD ($)
Segment Reporting [Abstract]        
Number of operating segments | segment     2  
Sales discounts | $ $ 2.5 $ 3.3 $ 4.7 $ 6.6
v3.25.2
Segment Reporting - Sales from Products (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Segment Reporting Information [Line Items]        
Sales $ 15,806 $ 16,112 $ 31,335 $ 31,887
Increase in hedge revenue     16 118
Revenue related to the sale of the marketing rights     100 76
U.S.        
Segment Reporting Information [Line Items]        
Sales 8,836 7,876 17,359 15,354
Non-US        
Segment Reporting Information [Line Items]        
Sales 6,969 8,236 13,977 16,533
Operating Segments        
Segment Reporting Information [Line Items]        
Sales 15,696 15,890 30,922 31,408
Operating Segments | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 14,050 14,408 27,688 28,415
Operating Segments | Animal Health        
Segment Reporting Information [Line Items]        
Sales 1,646 1,482 3,234 2,993
Operating Segments | U.S.        
Segment Reporting Information [Line Items]        
Sales 8,827 7,854 17,255 15,265
Operating Segments | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 8,328 7,399 16,254 14,336
Operating Segments | U.S. | Animal Health        
Segment Reporting Information [Line Items]        
Sales 499 455 1,001 929
Operating Segments | Non-US        
Segment Reporting Information [Line Items]        
Sales 6,869 8,036 13,667 16,143
Operating Segments | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 5,722 7,009 11,434 14,079
Operating Segments | Non-US | Animal Health        
Segment Reporting Information [Line Items]        
Sales 1,147 1,027 2,233 2,064
Operating Segments | Keytruda | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 7,956 7,270 15,161 14,217
Operating Segments | Keytruda | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 4,749 4,412 9,057 8,531
Operating Segments | Keytruda | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 3,207 2,858 6,104 5,686
Operating Segments | Alliance revenue - Lynparza | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 370 317 682 609
Operating Segments | Alliance revenue - Lynparza | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 174 153 319 288
Operating Segments | Alliance revenue - Lynparza | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 195 165 363 321
Operating Segments | Alliance revenue - Lenvima | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 265 249 523 504
Operating Segments | Alliance revenue - Lenvima | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 183 177 368 349
Operating Segments | Alliance revenue - Lenvima | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 83 73 155 155
Operating Segments | Welireg | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 162 126 300 211
Operating Segments | Welireg | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 138 116 261 194
Operating Segments | Welireg | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 24 10 39 17
Operating Segments | Alliance Revenue - Reblozyl | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 107 90 226 161
Operating Segments | Alliance Revenue - Reblozyl | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 88 75 189 133
Operating Segments | Alliance Revenue - Reblozyl | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 19 15 37 28
Operating Segments | Gardasil/Gardasil 9 | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 1,126 2,478 2,453 4,727
Operating Segments | Gardasil/Gardasil 9 | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 545 536 1,082 1,024
Operating Segments | Gardasil/Gardasil 9 | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 581 1,941 1,371 3,702
Operating Segments | ProQuad/M-M-R II/Varivax | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 609 617 1,148 1,187
Operating Segments | ProQuad/M-M-R II/Varivax | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 481 490 903 928
Operating Segments | ProQuad/M-M-R II/Varivax | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 128 127 245 259
Operating Segments | Vaxneuvance | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 229 189 459 408
Operating Segments | Vaxneuvance | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 136 99 275 260
Operating Segments | Vaxneuvance | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 93 90 184 148
Operating Segments | RotaTeq | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 121 163 349 379
Operating Segments | RotaTeq | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 60 107 225 257
Operating Segments | RotaTeq | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 61 56 125 123
Operating Segments | Capvaxive | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 129 0 236 0
Operating Segments | Capvaxive | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 129 0 235 0
Operating Segments | Capvaxive | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 0 1 0
Operating Segments | Pneumovax 23 | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 38 59 79 120
Operating Segments | Pneumovax 23 | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 5 11 3 17
Operating Segments | Pneumovax 23 | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 33 48 76 103
Operating Segments | Bridion | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 461 455 902 895
Operating Segments | Bridion | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 411 351 789 680
Operating Segments | Bridion | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 50 104 113 215
Operating Segments | Prevymis | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 228 188 436 362
Operating Segments | Prevymis | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 115 90 217 165
Operating Segments | Prevymis | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 113 98 219 197
Operating Segments | Dificid | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 96 92 179 165
Operating Segments | Dificid | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 83 79 155 147
Operating Segments | Dificid | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 13 12 24 17
Operating Segments | Zerbaxa | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 74 62 145 118
Operating Segments | Zerbaxa | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 45 33 87 67
Operating Segments | Zerbaxa | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 29 28 57 51
Operating Segments | Winrevair | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 336 70 615 70
Operating Segments | Winrevair | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 323 70 591 70
Operating Segments | Winrevair | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 12 0 24 0
Operating Segments | Alliance revenue - Adempas/Verquvo | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 123 106 229 203
Operating Segments | Alliance revenue - Adempas/Verquvo | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 108 98 205 188
Operating Segments | Alliance revenue - Adempas/Verquvo | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 15 8 23 16
Operating Segments | Adempas | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 80 72 147 142
Operating Segments | Adempas | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 0 0 0
Operating Segments | Adempas | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 80 72 147 142
Operating Segments | Lagevrio | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 83 110 185 460
Operating Segments | Lagevrio | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 30 15 66 60
Operating Segments | Lagevrio | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 52 95 119 400
Operating Segments | Isentress/Isentress HD | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 86 89 176 200
Operating Segments | Isentress/Isentress HD | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 48 43 99 93
Operating Segments | Isentress/Isentress HD | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 38 46 77 107
Operating Segments | Delstrigo | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 83 60 150 116
Operating Segments | Delstrigo | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 14 14 29 26
Operating Segments | Delstrigo | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 70 45 121 89
Operating Segments | Pifeltro | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 41 39 86 81
Operating Segments | Pifeltro | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 25 27 57 56
Operating Segments | Pifeltro | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 16 12 29 25
Operating Segments | Belsomra | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 40 53 90 99
Operating Segments | Belsomra | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 18 19 31 33
Operating Segments | Belsomra | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 21 34 58 66
Operating Segments | Simponi | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 172 0 356
Operating Segments | Simponi | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 0 0 0
Operating Segments | Simponi | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 172 0 356
Operating Segments | Remicade | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 35 0 74
Operating Segments | Remicade | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 0 0 0
Operating Segments | Remicade | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 35 0 74
Operating Segments | Januvia | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 372 405 921 824
Operating Segments | Januvia | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 216 177 561 361
Operating Segments | Januvia | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 155 227 360 463
Operating Segments | Janumet | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 251 224 498 475
Operating Segments | Janumet | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 68 17 133 55
Operating Segments | Janumet | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 184 208 366 420
Operating Segments | Other pharmaceutical | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 584 618 1,313 1,252
Operating Segments | Other pharmaceutical | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 136 190 317 354
Operating Segments | Other pharmaceutical | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 450 430 997 899
Operating Segments | Livestock | Animal Health        
Segment Reporting Information [Line Items]        
Sales 961 837 1,885 1,686
Operating Segments | Livestock | U.S. | Animal Health        
Segment Reporting Information [Line Items]        
Sales 190 168 384 334
Operating Segments | Livestock | Non-US | Animal Health        
Segment Reporting Information [Line Items]        
Sales 771 669 1,501 1,352
Operating Segments | Companion Animal | Animal Health        
Segment Reporting Information [Line Items]        
Sales 685 645 1,349 1,307
Operating Segments | Companion Animal | U.S. | Animal Health        
Segment Reporting Information [Line Items]        
Sales 309 287 617 595
Operating Segments | Companion Animal | Non-US | Animal Health        
Segment Reporting Information [Line Items]        
Sales 376 358 732 712
Corporate, Non-Segment        
Segment Reporting Information [Line Items]        
Sales 110 222 413 479
Corporate, Non-Segment | U.S.        
Segment Reporting Information [Line Items]        
Sales 9 22 104 89
Corporate, Non-Segment | Non-US        
Segment Reporting Information [Line Items]        
Sales $ 100 $ 200 $ 310 $ 390
v3.25.2
Segment Reporting - Consolidated Sales by Geographic Area (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Revenue from External Customer [Line Items]        
Sales $ 15,806 $ 16,112 $ 31,335 $ 31,887
United States        
Revenue from External Customer [Line Items]        
Sales 8,836 7,876 17,359 15,354
Europe, Middle East and Africa        
Revenue from External Customer [Line Items]        
Sales 3,659 3,515 7,109 7,078
Latin America        
Revenue from External Customer [Line Items]        
Sales 859 858 1,651 1,655
Asia Pacific (other than China and Japan)        
Revenue from External Customer [Line Items]        
Sales 785 748 1,474 1,472
Japan        
Revenue from External Customer [Line Items]        
Sales 626 686 1,295 1,507
China        
Revenue from External Customer [Line Items]        
Sales 446 1,817 1,148 3,589
Other        
Revenue from External Customer [Line Items]        
Sales $ 595 $ 612 $ 1,299 $ 1,232
v3.25.2
Segment Reporting - Reconciliation of Segment Profits to Income before Taxes (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Segment Reporting Information [Line Items]        
Sales $ 15,806 $ 16,112 $ 31,335 $ 31,887
Less segment costs:        
Cost of sales 3,557 3,745 6,976 7,285
Selling, general and administrative 2,649 2,739 5,202 5,221
Research and development (4,048) (3,500) (7,669) (7,492)
Other segment items 7 (42) 43 (12)
Total segment profits 4,999 6,006 10,902 11,675
Other profits 4,999 6,006 10,902 11,675
Unallocated:        
Interest income 69 69 178 141
Interest expense (305) (310) (618) (613)
Amortization     (1,198) (1,087)
Depreciation     (1,020) (1,029)
Research and development (4,048) (3,500) (7,669) (7,492)
Restructuring costs (560) (80) (629) (202)
Total segment profits        
Segment Reporting Information [Line Items]        
Sales 15,696 15,890 30,922 31,408
Less segment costs:        
Total segment profits 11,607 11,708 22,952 23,168
Other profits 11,607 11,708 22,952 23,168
Unallocated:        
Depreciation (63) (68) (124) (127)
Total segment profits | Pharma- ceutical        
Segment Reporting Information [Line Items]        
Sales 14,050 14,408 27,688 28,415
Less segment costs:        
Cost of sales 1,601 1,708 3,174 3,414
Selling, general and administrative 1,456 1,514 2,858 2,943
Research and development 0 0 0 0
Other segment items (21) (14) (70) (46)
Total segment profits 11,014 11,200 21,726 22,104
Other profits 11,014 11,200 21,726 22,104
Unallocated:        
Depreciation (1) (1) (2) (2)
Research and development 0 0 0 0
Total segment profits | Animal Health        
Segment Reporting Information [Line Items]        
Sales 1,646 1,482 3,234 2,993
Less segment costs:        
Cost of sales 659 612 1,258 1,225
Selling, general and administrative 284 270 544 523
Research and development (110) (91) (205) (181)
Other segment items 0 1 1 0
Total segment profits 593 508 1,226 1,064
Other profits 593 508 1,226 1,064
Unallocated:        
Depreciation (62) (67) (122) (125)
Research and development (110) (91) (205) (181)
Other profits        
Segment Reporting Information [Line Items]        
Sales 110 222 413 479
Less segment costs:        
Research and development (3,844) (3,360) (7,321) (7,209)
Total segment profits 30 129 231 274
Other profits 30 129 231 274
Unallocated:        
Interest income 69 69 178 141
Interest expense (305) (310) (618) (613)
Amortization (601) (614) (1,198) (1,087)
Depreciation (455) (450) (896) (902)
Research and development (3,844) (3,360) (7,321) (7,209)
Restructuring costs (560) (80) (629) (202)
Other unallocated, net $ (942) $ (1,086) $ (1,797) $ (1,895)
v3.25.2
Segment Reporting - Equity Income from Affiliates and Depreciation Included in Segment Profits (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Segment Reporting Information [Line Items]        
Depreciation     $ 1,020 $ 1,029
Operating Segments        
Segment Reporting Information [Line Items]        
Equity income from affiliates $ 29 $ 29 86 77
Depreciation 63 68 124 127
Operating Segments | Pharma- ceutical        
Segment Reporting Information [Line Items]        
Equity income from affiliates 29 29 86 77
Depreciation 1 1 2 2
Operating Segments | Animal Health        
Segment Reporting Information [Line Items]        
Equity income from affiliates 0 0 0 0
Depreciation $ 62 $ 67 $ 122 $ 125
v3.25.2
Segment Reporting - Property, Plant and Equipment, Net by Geographic Area (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net $ 25,236 $ 23,779
U.S.    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 15,182 14,724
Europe, Middle East and Africa    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 8,554 7,548
Asia Pacific (other than China and Japan)    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 966 982
China    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 204 202
Japan    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 144 143
Latin America    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 135 133
Other    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net $ 51 $ 47