MERCK & CO., INC., 10-Q filed on 5/4/2026
Quarterly Report
v3.26.1
Cover Page - shares
 3 Months Ended
Mar. 31, 2026
Apr. 30, 2026
Entity Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2026  
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   2,469,824,415
Amendment Flag false  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q1  
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 ($0.50 par value)  
Trading Symbol MRK  
Security Exchange Name NYSE  
1.875% Notes due 2026    
Entity Information [Line Items]    
Title of 12(b) Security 1.875% Notes due 2026  
Trading Symbol MRK/26  
Security Exchange Name NYSE  
3.250% Notes due 2032    
Entity Information [Line Items]    
Title of 12(b) Security 3.250% Notes due 2032  
Trading Symbol MRK/32  
Security Exchange Name NYSE  
2.500% Notes due 2034    
Entity Information [Line Items]    
Title of 12(b) Security 2.500% Notes due 2034  
Trading Symbol MRK/34  
Security Exchange Name NYSE  
1.375% Notes due 2036    
Entity Information [Line Items]    
Title of 12(b) Security 1.375% Notes due 2036  
Trading Symbol MRK 36A  
Security Exchange Name NYSE  
3.500% Notes due 2037    
Entity Information [Line Items]    
Title of 12(b) Security 3.500% Notes due 2037  
Trading Symbol MRK/37  
Security Exchange Name NYSE  
3.700% Notes due 2044    
Entity Information [Line Items]    
Title of 12(b) Security 3.700% Notes due 2044  
Trading Symbol MRK/44  
Security Exchange Name NYSE  
3.750% Notes due 2054    
Entity Information [Line Items]    
Title of 12(b) Security 3.750% Notes due 2054  
Trading Symbol MRK/54  
Security Exchange Name NYSE  
v3.26.1
CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Income Statement [Abstract]    
Sales $ 16,286 $ 15,529
Costs, Expenses and Other    
Cost of sales 4,195 3,419
Selling, general and administrative 2,700 2,552
Research and development 12,592 3,621
Restructuring costs 195 69
Other (income) expense, net 138 (35)
Total Costs, Expenses and Other 19,820 9,626
(Loss) Income Before Taxes (3,534) 5,903
Income Tax Provision 709 818
Net (Loss) Income (4,243) 5,085
Less: Net (Loss) Income Attributable to Noncontrolling Interests (3) 6
Net (Loss) Income Attributable to Merck & Co., Inc. $ (4,240) $ 5,079
Basic (Loss) Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ (1.72) $ 2.01
(Loss) Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ (1.72) $ 2.01
v3.26.1
CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE (LOSS) INCOME - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Statement of Comprehensive Income [Abstract]    
Net (Loss) Income Attributable to Merck & Co., Inc. $ (4,240) $ 5,079
Other Comprehensive Income (Loss) Net of Taxes:    
Net unrealized gain (loss) on derivatives, net of reclassifications 216 (217)
Benefit plan net gain (loss) and prior service credit (cost), net of amortization 5 (18)
Cumulative translation adjustment 6 215
Other comprehensive income (loss), net of taxes 227 (20)
Comprehensive (Loss) Income Attributable to Merck & Co., Inc. $ (4,013) $ 5,059
v3.26.1
CONDENSED CONSOLIDATED BALANCE SHEET - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Current Assets    
Cash and cash equivalents $ 5,327 $ 14,565
Short-term investments 375 0
Accounts receivable (net of allowance for doubtful accounts of $103 in 2026 and $97 in 2025) 12,210 11,775
Inventories (excludes inventories of $6,195 in 2026 and $5,681 in 2025 classified in Other assets - see Note 6) 6,479 6,658
Other current assets 10,624 10,518
Total current assets 35,015 43,516
Investments 1,105 956
Property, Plant and Equipment, at cost, net of accumulated depreciation of $22,288 in 2026 and $21,914 in 2025 25,433 25,316
Goodwill 21,581 21,579
Other Intangibles, Net 25,745 26,681
Other Assets 19,806 18,818
Total Assets 128,685 136,866
Current Liabilities    
Loans payable and current portion of long-term debt 2,444 2,589
Trade accounts payable 3,863 4,404
Accrued and other current liabilities 14,549 14,468
Income taxes payable 3,946 4,726
Dividends payable 2,143 2,140
Total current liabilities 26,945 28,327
Long-Term Debt 46,673 46,750
Deferred Income Taxes 1,494 1,439
Other Noncurrent Liabilities 7,642 7,688
Merck & Co., Inc. Stockholders’ Equity    
Common stock, $0.50 par value Authorized - 6,500,000,000 shares Issued - 3,577,103,522 shares in 2026 and 2025 1,788 1,788
Other paid-in capital 45,176 45,029
Retained earnings 66,721 73,075
Accumulated other comprehensive loss (4,060) (4,287)
Stockholders' equity before deduction for treasury stock 109,625 115,605
Less treasury stock, at cost: 1,107,410,143 shares in 2026 and 1,102,476,756 shares in 2025 63,747 62,999
Total Merck & Co., Inc. stockholders’ equity 45,878 52,606
Noncontrolling Interests 53 56
Total equity 45,931 52,662
Liabilities and Equity $ 128,685 $ 136,866
v3.26.1
CONDENSED CONSOLIDATED BALANCE SHEET (Parenthetical) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Statement of Financial Position [Abstract]    
Allowance for doubtful accounts $ 103 $ 97
Inventories classified in other assets 6,195 5,681
Accumulated depreciation $ 22,288 $ 21,914
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) 1,107,410,143 1,102,476,756
v3.26.1
CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Cash Flows from Operating Activities    
Net (loss) income $ (4,243) $ 5,085
Adjustments to reconcile net (loss) income to net cash provided by operating activities:    
Amortization 931 597
Depreciation 581 502
Income from investments in equity securities, net (168) (90)
Charge for research and development asset acquisition 8,540 0
Deferred income taxes (315) (186)
Share-based compensation 185 195
Other 20 109
Net changes in assets and liabilities (1,613) (3,712)
Net Cash Provided by Operating Activities 3,918 2,500
Cash Flows from Investing Activities    
Capital expenditures (991) (1,328)
Purchases of securities and other investments (374) (595)
Proceeds from sales of securities and other investments 0 456
Acquisition of Cidara Therapeutics, Inc., net of cash acquired (8,779) 0
Other (66) (20)
Net Cash Used in Investing Activities (10,210) (1,487)
Cash Flows from Financing Activities    
Net change in short-term borrowings 1,061 0
Payments on debt (1,140) (2,500)
Dividends paid to stockholders (2,105) (2,050)
Purchases of treasury stock (874) (1,164)
Proceeds from exercise of stock options 157 19
Other (80) (60)
Net Cash Used in Financing Activities (2,981) (5,755)
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash (19) 156
Net Decrease in Cash, Cash Equivalents and Restricted Cash (9,292) (4,586)
Cash, Cash Equivalents and Restricted Cash at Beginning of Year (includes restricted cash of $125 and $76 at January 1, 2026 and 2025, respectively, included in Other current assets) 14,690 13,318
Cash, Cash Equivalents and Restricted Cash at End of Period (includes restricted cash of $71 and $103 at March 31, 2026 and 2025, respectively, included in Other current assets) $ 5,398 $ 8,732
v3.26.1
CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Parenthetical) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Mar. 31, 2025
Dec. 31, 2024
Statement of Cash Flows [Abstract]        
Restricted cash $ 71 $ 125 $ 103 $ 76
v3.26.1
Basis of Presentation
 3 Months Ended
Mar. 31, 2026
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 24, 2026.
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 November 2024, the Financial Accounting Standards Board (FASB) issued guidance intended to improve financial reporting by requiring entities to disclose additional information about specific expense categories for 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.
In December 2025, the FASB issued guidance that includes requirements for recognition of government grants in a company’s financial statements as well as disclosure requirements, including the nature of the government grant received, the accounting policies used to account for the grant, and significant terms and conditions of the grant. The guidance is effective for 2029 interim and annual reporting on a modified prospective, modified retrospective or retrospective approach. Early adoption is permitted as of the beginning of an annual reporting period. The Company is currently evaluating the impact of adoption on its consolidated financial statements.
v3.26.1
Acquisitions, Research Collaborations and Licensing Agreements
 3 Months Ended
Mar. 31, 2026
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.
2026 Transactions
In March 2026, Merck entered into a definitive agreement to acquire Terns Pharmaceuticals, Inc. (Terns), a clinical-stage oncology company, for $53 per share, for a total transaction value of approximately $6.7 billion. Through this acquisition, Merck will acquire Terns’ lead candidate, TERN-701, a novel investigational oral allosteric BCR::ABL1 tyrosine kinase inhibitor (TKI) currently being evaluated in a Phase 1/2 trial for patients with Philadelphia chromosome-positive, chronic phase chronic myeloid leukemia previously treated with at least one prior TKI and who experienced treatment failure, suboptimal response or treatment intolerance. The transaction has been approved by both Merck’s and Terns’ Boards of Directors. The acquisition is subject to a majority of Terns’ stockholders tendering their shares in the tender offer initiated by Merck in April 2026. The consummation of the proposed transaction is also subject to customary closing conditions. Merck anticipates the transaction will be accounted for as an asset acquisition since TERN-701 is expected to account for substantially all of the fair value of the gross assets to be acquired (excluding cash and deferred income taxes). Upon closing of the transaction, which is anticipated in May 2026, Merck expects to record a charge of approximately $5.8 billion to Research and development expenses. There are no future contingent payments associated with the acquisition.
In January 2026, Merck acquired Cidara Therapeutics, Inc. (Cidara), a biotechnology company developing drug-Fc conjugate (DFC) therapeutics, for $9.2 billion (including $570 million of payments to settle share-based equity awards of which $406 million related to unvested equity awards). Cidara’s lead DFC candidate, MK-1406 (formerly CD388), is a long-acting antiviral designed to prevent seasonal and pandemic influenza. MK-1406 is currently being evaluated in a Phase 3 trial among adult and adolescent participants who are at higher risk of developing complications from influenza. The transaction was accounted for as an asset acquisition since MK-1406 accounted for substantially all of the fair value of the gross assets acquired (excluding cash and deferred income taxes). Merck recorded a charge of $9.0 billion to Research and development expenses (which primarily represented acquired in-process research and development with no alternative future use), as well as net assets of $332 million in the first quarter of 2026. Under a previous license agreement between Cidara and J&J Innovative Medicine (a Johnson & Johnson company, previously Janssen Pharmaceuticals, Inc.), which was assumed by Merck, J&J Innovative Medicine is eligible to receive up to $105 million in regulatory milestones and up to $455 million in sales-based milestones related to MK-1406.
2025 Transactions
In October 2025, Merck and Blackstone Life Sciences (Blackstone) entered into a funding arrangement under which Blackstone will pay Merck $700 million in the fourth quarter of 2026 (which is non-refundable, subject to the termination provisions of the agreement) to fund a portion of the Company’s development costs for MK-2870, sacituzumab tirumotecan (sac-TMT), expected to be incurred throughout 2026. Under the terms of the agreement, Merck recognized $200 million of funding in the first quarter of 2026 as a reduction to Research and development expenses, and also recognized a corresponding receivable from Blackstone, which was recorded in Other current assets. Upon receipt of regulatory approval for an indication in the U.S. for first-line triple-negative-breast cancer (TroFuse-011 trial), Blackstone will be eligible to receive low-to-mid single-digit royalties on net sales of sac-TMT subsequent to such approval across all approved indications in Merck’s marketing territories. Sac-TMT is an investigational trophoblast cell-surface antigen 2 (TROP2)-directed antibody drug conjugate (ADC) being developed as part of an exclusive license and collaboration agreement with Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (Kelun-Biotech) that is currently in clinical development for the treatment of a variety of cancers. The agreement between Merck and Kelun-Biotech with respect to sac-TMT is unchanged by the agreement with Blackstone. Merck retained decision-making authority and control over the development, manufacturing, and commercial activities relating to sac-TMT provided for in the agreement with Kelun-Biotech, and Blackstone did not receive any rights to sac-TMT.
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.
v3.26.1
Collaborative Arrangements
 3 Months Ended
Mar. 31, 2026
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. Under the terms of the agreement, AstraZeneca and Merck share the development and commercialization costs for Lynparza monotherapy and non-PD-1/PD-L1 combination therapy opportunities.
Profits from Lynparza product sales generated through monotherapies or combination therapies are shared equally. AstraZeneca is the principal on Lynparza sales transactions. Merck records its share of Lynparza 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.
The initial collaboration agreement also included the joint development and commercialization of AstraZeneca’s Koselugo (selumetinib) for multiple indications, with revenues, costs and profits being accounted for similar to Lynparza. In August 2025, Merck and AstraZeneca amended the terms of the original collaboration agreement, which resulted in the discontinuation of the revenue and cost sharing provisions of the collaboration and the simplification of the governance structure related to Koselugo. In exchange, Merck received a $150 million upfront payment (which was recorded within Sales as alliance revenue in the third quarter of 2025) and $150 million in February 2026 (which was recorded within Sales as alliance revenue in the first quarter of 2026). Merck may also receive $150 million in the first quarter of 2027 and $100 million in the first quarter of 2028, subject to an annual election by AstraZeneca in January of each year as discussed below. Additionally, the amended agreement provided for Merck to receive contingent regulatory milestone payments of up to $175 million in the aggregate, all of which were triggered in 2025 and recorded within Sales as alliance revenue. Of these milestone amounts, $50 million is due from AstraZeneca in the third quarter of 2026, $50 million is due in the third quarter of 2027, and $75 million is due in the third quarter of 2028. The Company is also receiving mid-single-digit royalties on net sales (which are included within Sales as alliance revenue). Merck remains eligible to receive future contingent payments for the achievement of sales-based milestones of up to $235 million. AstraZeneca has the option in January 2027 or January 2028 to revert back to the income and cost sharing terms of the original agreement (in which case any future annual, contingent milestone, and royalty payments referenced above would no longer be due) although Merck would retain any payments made by AstraZeneca prior to the exercise of that option and any amounts due from AstraZeneca would remain payable to Merck.
As part of the initial collaboration agreement, Merck made an upfront payment to AstraZeneca and also made payments over a multi-year period for certain license options. In addition, the initial collaboration agreement provided for contingent payments from Merck to AstraZeneca related to the successful achievement of sales-based and regulatory milestones. In the first quarter of 2025, Merck made sales-based milestone payments aggregating $700 million (related to the original collaboration agreement) 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. The partners have agreed that no future regulatory milestone payments from Merck to AstraZeneca are likely.
The intangible asset balances related to Lynparza and Koselugo (which reflect the capitalized sales-based and regulatory milestone payments attributed to each product) were $762 million and $36 million, respectively, at March 31, 2026 and are included in Other Intangibles, Net. The assets are being amortized over their estimated useful lives (through 2028 for Lynparza and through 2029 for Koselugo) as supported by projected future cash flows, subject to impairment testing.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Alliance revenue - Lynparza$341 $312 
Alliance revenue - Koselugo (1)
161 44 
Total alliance revenue$502 $356 
Cost of sales (2)
84 83 
Selling, general and administrative24 32 
Research and development5 12 
($ in millions)March 31, 2026December 31, 2025
Receivables from AstraZeneca included in Other current assets (3)
$401 $451 
Receivables from AstraZeneca included in Other assets (3)
125 125 
Payables to AstraZeneca included in Accrued and other current liabilities
12 6 
(1)    Amount in the first quarter of 2026 includes $150 million related to the amendment of the collaboration agreement noted above.
(2)    Represents amortization of capitalized milestone payments.
(3)    Includes milestone receivables.
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 TKI 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, as well as Welireg (belzutifan) 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. 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 $188 million at March 31, 2026 and is included in Other Intangibles, Net. The amount is being amortized over its estimated useful life through 2029 as supported by projected future cash flows, subject to impairment testing.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Alliance revenue - Lenvima$256 $258 
Cost of sales (1)
13 60 
Selling, general and administrative27 31 
Research and development2 5 
($ in millions)March 31, 2026December 31, 2025
Receivables from Eisai included in Other current assets
$252 $271 
(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. The agreement provided for contingent payments from Merck to Bayer related to the successful achievement of sales-based milestones. There are no such 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 $239 million and $37 million, respectively, at March 31, 2026 and are included in Other Intangibles, Net. The assets are being amortized over their estimated useful lives (through 2027 for Adempas and through 2031 for Verquvo) as supported by projected future cash flows, subject to impairment testing.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Alliance revenue - Adempas/Verquvo$109 $106 
Net sales of Adempas recorded by Merck78 68 
Net sales of Verquvo recorded by Merck9 9 
Total sales$196 $183 
Cost of sales (1)
67 58 
Selling, general and administrative12 29 
Research and development17 24 
($ in millions)March 31, 2026December 31, 2025
Receivables from Bayer included in Other current assets
$162 $167 
Payables to Bayer included in Accrued and other current liabilities
87 81 
(1)    Includes amortization of intangible assets, cost of products sold by Merck, as well as Bayer’s share of profits from sales in Merck’s marketing territories.
Ridgeback Biotherapeutics LP
In 2020, Merck and Ridgeback Biotherapeutics LP (Ridgeback), a closely held biotechnology company, entered into a collaboration agreement to develop Lagevrio (molnupiravir), an investigational orally available antiviral candidate for the treatment of patients with COVID-19. Merck gained exclusive worldwide rights to develop and commercialize Lagevrio and related molecules. Following initial authorizations in certain markets in 2021, Lagevrio has since received multiple additional authorizations.
Under the terms of the agreement, Ridgeback received an upfront payment and is eligible to receive future contingent payments dependent upon the achievement of certain developmental and regulatory approval milestones. The agreement also provides for Merck to reimburse Ridgeback for a portion of certain third-party contingent milestone payments and royalties on net sales, which is part of the profit-sharing calculation. Merck is the principal on sales transactions, recognizing sales and related costs, with profit-sharing amounts recorded within Cost of sales. Profits from the collaboration are split equally between the partners. Reimbursements from Ridgeback for its share of research and development costs (deducted from Ridgeback’s share of profits) are reflected as decreases to Research and development expenses.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Net sales of Lagevrio recorded by Merck
$28 $102 
Cost of sales (1)
54 53 
Selling, general and administrative
11 13 
Research and development
5 8 
(1)    Includes cost of products sold by Merck, Ridgeback’s share of profits, royalty expense, amortization of capitalized milestone payments and inventory reserves.
Daiichi Sankyo
In 2023, Merck and Daiichi Sankyo entered into a global development and commercialization agreement for three of Daiichi Sankyo’s DXd ADC candidates: patritumab deruxtecan (MK-1022), ifinatamab deruxtecan (MK-2400) and raludotatug deruxtecan (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 (which Merck paid in October 2025). 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.
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 2024, Merck and Daiichi Sankyo expanded their agreement to include gocatamig (MK-6070), an investigational DLL3 targeting T-cell engager, which Merck obtained through its acquisition of Harpoon Therapeutics, Inc. 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 $170 million from Daiichi Sankyo (recorded within Other (income) expense, net) and has also satisfied a contingent quid obligation from the original collaboration agreement. The companies will jointly develop and commercialize gocatamig worldwide and share research and development costs, as well as commercialization expenses. Research and development expenses related to gocatamig in combination with ifinatamab deruxtecan will be shared in a manner consistent with the original agreement for ifinatamab deruxtecan. Merck will be solely responsible for manufacturing and supply of gocatamig. If approved, Merck will generally record sales for gocatamig worldwide (Merck will be the principal on sales transactions) and the companies will equally share expenses as well as profits worldwide, except for Japan where Merck retains exclusive rights and Daiichi Sankyo will receive a 5% sales-based royalty.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Selling, general and administrative $12 $9 
Research and development
160 128 
($ in millions)March 31, 2026December 31, 2025
Receivables from Daiichi Sankyo included in Other current assets
$22 $15 
Payables to Daiichi Sankyo included in Accrued and other current liabilities
85 113 
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 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 a net $230 million of shared facility costs at March 31, 2026, primarily reflected within Other Assets. These costs are amortized over the assets’ estimated useful lives.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Selling, general and administrative $8 $6 
Research and development (1)
90 86 
($ in millions)March 31, 2026December 31, 2025
Receivables from Moderna included in Other current assets
$4 $— 
Payables to Moderna included in Accrued and other current liabilities
— 13 
(1)    Includes amortization of shared facility costs.
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. 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 $148 million and $119 million in the first quarter of 2026 and 2025, respectively.
v3.26.1
Restructuring
 3 Months Ended
Mar. 31, 2026
Restructuring and Related Activities [Abstract]  
Restructuring Restructuring
In July 2025, the Company approved a 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 $318 million in the first quarter of 2026 related to the 2025 Restructuring Program. Since inception of the 2025 Restructuring Program through March 31, 2026, Merck has incurred total cumulative pretax costs of $2.3 billion.
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 50% 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 $148 million and $105 million in the first quarter of 2026 and 2025, respectively, related to the 2024 Restructuring Program. Since inception of the 2024 Restructuring Program through March 31, 2026, Merck has incurred total cumulative pretax costs of $1.8 billion.
For segment reporting, restructuring charges are unallocated expenses.
The following tables summarize the charges related to restructuring program activities by type of cost:
 Three Months Ended March 31, 2026
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
2025 Restructuring Program
Cost of sales$12 $— $132 $144 
Research and development— — 34 34 
Restructuring costs— 123 17 140 
12 123 183 318 
2024 Restructuring Program
Cost of sales96 — (3)93 
Restructuring costs— — 55 55 
96 — 52 148 
$108 $123 $235 $466 
 Three Months Ended March 31, 2025
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
2024 Restructuring Program
Cost of sales$41 $— $(5)$36 
Restructuring costs— 1 68 69 
$41 $1 $63 $105 
Accelerated depreciation costs primarily relate to manufacturing, research and administrative facilities to be fully or partially closed or divested and equipment to be disposed of as part of the programs. Accelerated depreciation costs represent the difference between the depreciation expense to be recognized over the revised useful life of the asset, based upon the anticipated date the site will be closed or divested or the equipment disposed of, and depreciation expense as determined utilizing the useful life prior to the restructuring actions. All the sites will continue to operate up through the respective closure dates and, since future undiscounted cash flows are sufficient to recover the respective book values, Merck is recording accelerated depreciation over the revised useful life of the site assets. Anticipated site closure dates, particularly related to manufacturing locations, have been and may continue to be adjusted to reflect changes resulting from regulatory or other factors.
Separation costs are associated with actual headcount reductions, as well as involuntary headcount reductions which were probable and could be reasonably estimated.
Other exit costs in 2026 and 2025 include asset impairment, facility shut-down, contractual termination, and other related costs, as well as pretax gains and losses resulting from the sales of facilities and related assets. Additionally, other activity includes certain employee-related costs associated with pension and other postretirement benefit plans (see Note 10) and share-based compensation.
The following table summarizes the charges and spending related to restructuring program activities for the three months ended March 31, 2026:
($ in millions)
Accelerated Depreciation
Separation
Costs
Other Exit Costs
Total
2025 Restructuring Program
Restructuring reserves January 1, 2026
$— $502 $288 $790 
Expenses
12 123 183 318 
(Payments) receipts, net— (156)(166)(322)
Non-cash activity(12)(9)(117)(138)
Restructuring reserves March 31, 2026
$— $460 $188 $648 
2024 Restructuring Program
Restructuring reserves January 1, 2026
$— $506 $— $506 
Expenses96 — 52 148 
(Payments) receipts, net— (70)(53)(123)
Non-cash activity(96)12 1 (83)
Restructuring reserves March 31, 2026
$— $448 $— $448 
v3.26.1
Financial Instruments
 3 Months Ended
Mar. 31, 2026
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 first quarter of either 2026 or 2025. 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 (Gain) Loss 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 March 31,Three Months Ended March 31,
($ in millions)2026202520262025
Net Investment Hedging Relationships
Foreign exchange contracts$(15)$27 $(4)$(3)
Euro-denominated notes(137)130 — — 
(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 March 31, 2026, the Company was a party to ten 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.
March 31, 2026
($ 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 
4.75% notes due 2035
1,500 2 500 
5.00% notes due 2053
1,500 2 500 
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 February 2026, the Company entered into two 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)
March 31, 2026December 31, 2025March 31, 2026December 31, 2025
Balance Sheet Caption
Long-Term Debt
$2,539 $1,810 $57 $70 
Presented in the table below is the fair value of derivatives on a gross basis segregated between those derivatives that are designated as hedging instruments and those that are not designated as hedging instruments:
  March 31, 2026December 31, 2025
  Fair Value of DerivativeU.S. Dollar
Notional		Fair Value of DerivativeU.S. Dollar
Notional
($ in millions)AssetLiabilityAssetLiability
Derivatives Designated as Hedging InstrumentsBalance Sheet Caption
Interest rate swap contracts
Other Assets
$58 $— $2,500 $71 $— $1,750 
Interest rate contracts
Other Assets
8 — 500 — — — 
Foreign exchange contractsOther current assets247 — 7,751 113 — 6,430 
Foreign exchange contractsOther Assets55 — 1,828 32 — 1,793 
Foreign exchange contractsAccrued and other current liabilities— 48 3,705 — 131 4,726 
Foreign exchange contractsOther Noncurrent Liabilities— 1 33 — 1 13 
  $368 $49 $16,317 $216 $132 $14,712 
Derivatives Not Designated as Hedging InstrumentsBalance Sheet Caption      
Foreign exchange contractsOther current assets$194 $— $13,870 $107 $— $11,643 
Foreign exchange contractsAccrued and other current liabilities— 180 11,919 — 191 13,579 
Foreign exchange contracts
Other Noncurrent Liabilities
— — — — 1 357 
  $194 $180 $25,789 $107 $192 $25,579 
  $562 $229 $42,106 $323 $324 $40,291 
As noted above, the Company records its derivatives on a gross basis in the Condensed Consolidated Balance Sheet. The Company has master netting agreements with several of its financial institution counterparties (see Concentrations of Credit Risk below). The following table provides information on the Company’s derivative positions subject to these master netting arrangements as if they were presented on a net basis, allowing for the right of offset by counterparty and cash collateral exchanged per the master agreements and related credit support annexes:
 March 31, 2026December 31, 2025
($ in millions)AssetLiabilityAssetLiability
Gross amounts recognized in the condensed consolidated balance sheet$562 $229 $323 $324 
Gross amounts subject to offset in master netting arrangements not offset in the condensed consolidated balance sheet(225)(225)(245)(245)
Cash collateral received
(89)— (1)— 
Net amounts$248 $4 $77 $79 
The table below provides information regarding the location and amount of pretax gains and losses of derivatives designated in fair value or cash flow hedging relationships:
Three Months Ended March 31,
($ in millions)202620252026202520262025
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)
$16,286 $15,529 $138 $(35)$227 $(20)
(Gain) loss on fair value hedging relationships:
Interest rate swap contracts
Hedged items— — (14)38 — — 
Derivatives designated as hedging instruments— — 13 (39)— — 
Impact of cash flow hedging relationships:
Foreign exchange contracts
Amount of gain (loss) recognized in OCI on derivatives
— — — — 168 (201)
(Decrease) increase in Sales as a result of AOCL reclassifications
(98)74 — — 98 (74)
Interest rate contracts
Amount of gain recognized in Other (income) expense, net on derivatives
— — (1)— — — 
Amount of gain recognized in OCI on derivatives
— — — — 7 — 
(1)    Interest expense is a component of Other (income) expense, net.
The table below provides information regarding the income statement effects of derivatives not designated as hedging instruments:
Amount of Derivative Pretax Loss (Gain) Recognized in Income
Three Months Ended March 31,
($ in millions)20262025
Derivatives Not Designated as Hedging InstrumentsIncome Statement Caption
Foreign exchange contracts (1)
Other (income) expense, net$36 $(20)
Foreign exchange contracts (2)
Sales12 16 
(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 March 31, 2026, the Company estimates $69 million of pretax net unrealized gains on derivatives maturing within the next 12 months that hedge foreign currency denominated sales over that same period will be reclassified from AOCL to Sales. The amount ultimately reclassified to Sales may differ as foreign exchange rates change. Realized gains and losses are ultimately determined by actual foreign exchange rates at maturity.
Investments in Debt and Equity Securities
Information on investments in debt and equity securities is as follows:
 March 31, 2026December 31, 2025
 Amortized
Cost		Gross UnrealizedFair
Value		Amortized
Cost		Gross UnrealizedFair
Value
($ in millions)GainsLossesGainsLosses
Commercial paper$375 $— $— $375 $— $— $— $— 
U.S. government and agency securities100 — — 100 100 — — 100 
Foreign government bonds
1 — — 1 1 — — 1 
Total debt securities$476 $— $— $476 $101 $— $— $101 
Publicly traded equity securities (1)
1,571 1,392 
Total debt and publicly traded equity securities$2,047 $1,493 
(1)    Unrealized net gains of $126 million were recorded in Other (income) expense, net in the first quarter of 2026 on equity securities still held at March 31, 2026. Unrealized net gains of $115 million were recorded in Other (income) expense, net in the first quarter of 2025 on equity securities still held at March 31, 2025.
At March 31, 2026 and March 31, 2025, the Company also had $881 million and $872 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 quarter of 2026, the Company recorded unrealized gains of $35 million related to certain of these equity investments still held at March 31, 2026. During the first quarter of 2025, the Company recorded unrealized losses of $11 million related to certain of these equity investments still held at March 31, 2025. 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 March 31, 2026 were $320 million and $164 million, respectively.
At March 31, 2026 and March 31, 2025, the Company also had $229 million and $249 million, respectively, recorded in Other Assets for equity securities held through ownership interests in investment funds. (Gains) losses recorded in Other (income) expense, net relating to these investment funds were $(3) million and $23 million for the first quarter of 2026 and 2025, respectively.
Fair Value Measurements
Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company uses a fair value hierarchy which maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value. There are three levels of inputs used to measure fair value with Level 1 having the highest priority and Level 3 having the lowest:
Level 1 - Quoted prices (unadjusted) in active markets for identical assets or liabilities.
Level 2 - Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
Level 3 - Unobservable inputs that are supported by little or no market activity. Level 3 assets or liabilities are those whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques with significant unobservable inputs, as well as assets or liabilities for which the determination of fair value requires significant judgment or estimation.
If the inputs used to measure the financial assets and liabilities fall within more than one level described above, the categorization is based on the lowest level input that is significant to the fair value measurement of the instrument.
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis
Financial assets and liabilities measured at fair value on a recurring basis are summarized below:
Fair Value Measurements UsingFair Value Measurements Using
 Level 1Level 2Level 3TotalLevel 1Level 2Level 3Total
($ in millions)March 31, 2026December 31, 2025
Assets
Investments
Commercial paper$— $375 $— $375 $— $— $— $— 
Foreign government bonds
— 1 — 1 — 1 — 1 
Publicly traded equity securities1,104 — — 1,104 955 — — 955 
 1,104 376 — 1,480 955 1 — 956 
Other assets (1)
U.S. government and agency securities100 — — 100 100 — — 100 
Publicly traded equity securities (2)
467 — — 467 437 — — 437 
567 — — 567 537 — — 537 
Derivative assets (3)
Forward exchange contracts— 310 — 310 — 168 — 168 
Purchased currency options— 186 — 186 — 84 — 84 
Interest rate swaps
— 58 — 58 — 71 — 71 
Interest rate contracts
— 8 — 8 — — — — 
 — 562 — 562 — 323 — 323 
Total assets$1,671 $938 $— $2,609 $1,492 $324 $— $1,816 
Liabilities
Derivative liabilities (3)
Forward exchange contracts$— $202 $— $202 $— $293 $— $293 
Written currency options— 27 — 27 — 31 — 31 
Total liabilities$— $229 $— $229 $— $324 $— $324 
(1)    Investments included in other assets are restricted as to use, including for the payment of benefits under employee benefit plans.
(2)    Balance at March 31, 2026 includes securities with a fair value of $17 million that are subject to a contractual sale restriction that expires in July 2026, and securities with a fair value of $18 million that are subject to a contractual sale restriction that expires in August 2026.
(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 March 31, 2026 and December 31, 2025, Cash and cash equivalents included $4.4 billion and $13.8 billion of cash equivalents, respectively (which would be considered Level 2 in the fair value hierarchy).
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 March 31, 2026, was $44.7 billion compared with a carrying value of $49.1 billion and at December 31, 2025, was $45.6 billion compared with a carrying value of $49.3 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. and Europe 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 of accounts receivable as of both March 31, 2026 and December 31, 2025 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 March 31, 2026 and
December 31, 2025, the Company had collected $39 million and $45 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 received by the Company from various counterparties was $89 million and $1 million at March 31, 2026 and December 31, 2025, respectively. The obligation to return such collateral is recorded in Accrued and other current liabilities.
v3.26.1
Inventories
 3 Months Ended
Mar. 31, 2026
Inventory Disclosure [Abstract]  
Inventories Inventories
Inventories consisted of:
($ in millions)March 31, 2026December 31, 2025
Finished goods$2,211 $2,275 
Raw materials and work in process11,136 10,645 
Supplies334 331 
Total13,681 13,251 
Decrease to LIFO cost(1,007)(912)
 $12,674 $12,339 
Recognized as:
Inventories$6,479 $6,658 
Other Assets6,195 5,681 
Amounts recognized as Other Assets are comprised almost entirely of raw materials and work in process inventories. At March 31, 2026 and December 31, 2025, these amounts included $5.8 billion and $5.5 billion, respectively, of inventories not expected to be sold within one year. In addition, these amounts included $360 million and $211 million at March 31, 2026 and December 31, 2025, respectively, of inventories produced in preparation for product launches.
v3.26.1
Loans Payable
 3 Months Ended
Mar. 31, 2026
Debt Disclosure [Abstract]  
Loans Payable Loans Payable
In April 2026, Merck entered into a delayed draw term loan credit agreement (Credit Agreement) pursuant to which the lenders have committed (subject to satisfaction of certain conditions set forth in the Credit Agreement) to provide Merck with financing under a 364-day term loan facility in an aggregate amount not to exceed $6.0 billion. Borrowings under the Credit Agreement will bear interest at an annual rate of the SOFR rate plus 0.50% from the date loans are borrowed (Funding Date) to the date that is 180 days from the Funding Date, and then the SOFR rate plus 0.75% thereafter. The Company has given required notice to the lenders of its intention to draw down the $6.0 billion of funds under the facility, which will be used to fund a portion of the approximately $6.7 billion cash consideration for the acquisition of Terns. The Company intends to use the proceeds from a long-term debt financing to repay borrowings under the Credit Agreement.
v3.26.1
Contingencies
 3 Months Ended
Mar. 31, 2026
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 March 31, 2026, approximately 735 cases were pending against Merck in various state courts.
The Company was recently the defendant in a trial in Chicago, Illinois, in which it was found to be not liable for the plaintiff’s mesothelioma. The Company anticipates that there will be additional trials in the Dr. Scholl’s litigation in the future.
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 March 31, 2026, approximately 135 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 on the remaining alleged conditions and summary judgment briefing are to follow.
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 been adjourned until a new trial date of July 27, 2026. 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, in October 2025, Merck entered into a proposed agreement with plaintiffs’ counsel to substantially resolve the Gardasil product liability litigation. The proposed agreement sets forth various terms and conditions under which Merck would resolve the bulk of all pending Gardasil product liability claims in the U.S. in exchange for a total payment that is considerably less than Merck’s anticipated costs of defense in the litigation and that is not material to Merck. The proposed agreement requires that several conditions be met within specified time periods, including participation thresholds, in order for the proposed agreement to result in a final resolution of any pending litigation.
As previously disclosed, there are fewer than 15 product liability cases pending outside the U.S.
Governmental Proceedings
Civil Investigative Demands
As previously disclosed, in August 2025, the Company received a Civil Investigative Demand (CID) from the U.S. Department of Justice (DOJ), pursuant to a False Claims Act investigation, seeking documents, information, and testimony related to the Company’s programs and practices concerning diversity, equity, and inclusion. The CID states that the DOJ is investigating whether, in connection with the Company’s claims for payments under its federal contracts, the Company falsely certified compliance with federal antidiscrimination laws. The Company is cooperating with the investigation.
As previously disclosed, in June 2024, Merck received a CID from the DOJ, pursuant to a False Claims Act investigation, seeking documents and materials related to Steglatro, Januvia and certain related drugs. The CID states that it is investigating Merck’s price reporting under the Medicaid Drug Rebate Program as well as compliance with anti-kickback requirements in connection with patient assistance programs. The Company is cooperating with the investigation.
Other Matters
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, on February 12, 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 October 26, 2023, and February 3, 2025. Plaintiff alleges that Merck violated federal securities laws by making materially false and misleading statements and omissions regarding demand for Gardasil/Gardasil 9 in China. On December 17, 2025, the court appointed AMF Tjänstepension AB, KBC Asset Management NV, and Wayne County Employees’ Retirement System as lead plaintiffs (Lead Plaintiffs). Lead Plaintiffs filed an amended complaint on February 20, 2026, seeking unspecified damages allegedly caused by the purported false or misleading statements. Defendants filed a motion to dismiss on May 1, 2026. The opposition brief is due June 30, 2026 and the reply brief is due August 14, 2026.
As previously disclosed, various derivative lawsuits were filed in New Jersey state and federal court against certain current and former Merck officers and board members. The derivative lawsuits assert claims under state and federal securities statutes, as well as New Jersey common law, based on the same allegations as those made in the putative securities class action. These derivative lawsuits seek unspecified monetary damages, corporate governance reforms, injunctive relief, disgorgement of profits, restitution, fees, and costs. All the derivative proceedings are stayed pending further developments in the class action.
Commercial and Other Litigation
RotaTeq Antitrust Litigation
As previously disclosed, in March 2023, the Mayor and City Council of Baltimore filed a putative class action against MSD in the Eastern District of Pennsylvania on behalf of all third-party payers in states that indirectly purchased, paid, and/or provided reimbursement for some or all of the purchase price of RotaTeq (Rotavirus Vaccine, Live Oral, Pentavalent), other than for resale, from March 3, 2019 to the present. Plaintiff alleges that MSD violated federal and state antitrust laws and state consumer protection laws. Plaintiff alleges that MSD has implemented an anticompetitive vaccine bundling scheme whereby MSD leverages its alleged monopoly power in certain pediatric vaccine markets to maintain its alleged monopoly power in the U.S. market for rotavirus vaccines in order to charge supracompetitive prices for RotaTeq. Plaintiff seeks permanent injunctive relief and unspecified monetary damages on purchases of RotaTeq, trebled, and fees and costs. In May 2023, MSD moved to dismiss the complaint. In November 2023, the court granted in part and denied in part the motion to dismiss, dismissing plaintiff’s Idaho and Utah consumer law claims and allowing all other claims to proceed.
On January 20, 2026, plaintiff filed a motion to certify the proposed class. On February 10, 2026, Merck filed an opposition to plaintiff’s motion to certify the proposed class and a motion to exclude plaintiff’s expert’s class certification opinions. Plaintiff filed a reply in support of its request to certify the class and an opposition to the motion to exclude on March 17, 2026. On March 31, 2026, Merck filed a reply in support of the motion to exclude plaintiff’s expert’s opinions. Merck also filed a sur-reply to the class certification motion.
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, 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 against those generic companies. The defendants in the New Jersey action referred to below 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.
As previously disclosed, 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 March 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. In addition, the FDA has now granted Bridion six months of pediatric exclusivity.
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 were subject to delay by any applicable pediatric exclusivity which has been granted) or earlier under certain circumstances. Thus, the Federal Circuit’s decision and these settlements secure Bridion’s exclusivity in the U.S. through July 27, 2026.
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, and their generic versions of Janumet XR to the market in July 2026 or earlier under certain circumstances.
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, Januvia and Janumet will lose market exclusivity in the U.S. in May 2026 and Janumet XR will lose market exclusivity in the U.S. in July 2026, although the FDA has approved 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, Finland, and France. 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. (Sawai) 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 anhydride 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. In January 2026, the Tokyo District Court orally indicated its view that the extended patent covers Sawai’s tablets. Following this, Sawai conceded to all of the Company’s claims; thus, the case was concluded without a written decision. The relevant PTE for Januvia in Japan expired on March 30, 2026.
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 U.S. 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.
As previously disclosed, between June and November 2025, the PTAB issued Final Written Decisions finding all challenged claims of the nine patents unpatentable. JHU has filed notices of appeal to the Federal Circuit Court of Appeals. The district court’s stay is expected to continue until at least the issuance of the Federal Circuit decision.
Subcutaneous Pembrolizumab — As previously disclosed, Halozyme, Inc. (Halozyme) has publicly alleged that certain patents in its modified hyaluronidase (MDASE) portfolio cover an ingredient in the Company’s subcutaneous pembrolizumab product. 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. In June 2025, the PTAB instituted the first petition filed by the Company. Since then, the PTAB also instituted 13 additional petitions. An institution decision on one additional patent in the MDASE portfolio is still pending.
In April 2025, Halozyme 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. The Company believes the three patents not challenged via PGR petitions are invalid and suffer from at least the same defects as the patents currently being challenged by the PGR process. In March 2026, the Company filed inter partes review (IPR) petitions against those three patents. The Company expects that the U.S. Patent and Trademark Office will issue an institution decision on these IPR petitions by late-September 2026.
Between August and September 2025, the Company filed revocation actions against EP Patent No. 2 797 622 (the ‘622 patent) owned by Halozyme in the UK, France, Germany and The Netherlands. Halozyme counterclaimed for an injunction in the UK under the ‘622 patent as well as an additional patent but have undertaken not to enforce any injunction there until the validity of both patents, which is in dispute, is finally determined. In October 2025, the Company accepted service of a preliminary injunction filed by Halozyme under the ‘622 patent in Germany. Following a one day hearing in December 2025, a preliminary injunction was awarded against the Company, prohibiting sales in Germany. The Company has appealed the preliminary injunction decision and expects a decision on the appeal in the second or third quarter of 2026. In the Dutch action, in February 2026, Halozyme counterclaimed for infringement including also Belgium, Denmark, France, Ireland, Italy, Sweden and Switzerland. The Dutch action will be heard at the end of July 2026 with a decision expected within three months thereof.
Lenvima — As previously disclosed, between 2019 and 2024, Eisai Inc (Eisai) received Paragraph IV Certification Letters under the Hatch-Waxman Act, providing notice that Sun Pharmaceuticals (Sun), Shilpa Medicare Ltd. (Shilpa), Dr. Reddy’s Laboratories (DRL), and Torrent Pharmaceuticals (Torrent) filed separate applications to the FDA seeking pre-patent expiry approval to sell generic versions of Lenvima (lenvatinib) tablets. Between 2019 and 2024, Eisai 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 several Orange-Book listed patents. The Lenvima compound patent expired in April 2026 (including pediatric exclusivity) and was not challenged. Eisai and the Company settled with Sun, DRL, and Torrent regarding the remaining asserted patents covering Lenvima. Eisai has announced publicly, these generic companies can bring their generic versions of Lenvima to the market in the U.S. in July 2030 or earlier under certain circumstances. In May 2025, Eisai and the Company received a favorable trial decision against Shilpa from the U.S. District Court for the District of New Jersey. As a result of the decision, Shilpa is unable to receive approval from the FDA to sell its generic version of Lenvima until February 2036. Shilpa has appealed the district court’s decision to the U.S. Court of Appeals for the Federal Circuit, and the appeal is currently pending.
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 now expected in early 2027.
Capvaxive — As previously disclosed, in September 2025, Pogona, LLC filed a complaint in the U.S. District Court for the District of New Jersey alleging that the Company’s activities related to Capvaxive infringe U.S. Patent No. 11,058,757 (‘757 patent). Pogona, LLC is asserting the Company’s infringement is willful and is seeking monetary damages. The Company believes the asserted patent is invalid and not infringed. On January 26, 2026, the Company filed an inter-partes review petition with the U.S. Patent Trial and Appeal Board, challenging the validity of Pogona’s ‘757 patent, which is currently pending.
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 March 31, 2026 and December 31, 2025 of approximately $270 million and $245 million, respectively, represents the Company’s best estimate of the minimum amount of defense costs to be incurred in connection with its outstanding litigation; however, events such as additional trials and other events that could arise in the course of its litigation could affect the ultimate amount of legal defense costs to be incurred by the Company. The Company will continue to monitor its legal defense costs and review the adequacy of the associated reserves and may determine to increase the reserves at any time in the future if, based upon the factors set forth, it believes it would be appropriate to do so.
v3.26.1
Equity
 3 Months Ended
Mar. 31, 2026
Equity [Abstract]  
Equity Equity
Three Months Ended March 31,
   Common StockOther
Paid-In
Capital		Retained
Earnings		Accumulated
Other
Comprehensive
Loss		 Treasury StockNon-
controlling
Interests		Total
($ and shares in millions except per share amounts)SharesPar ValueSharesCost
Balance at January 1, 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.
— — — 5,079 — — — — 5,079 
Other comprehensive loss, net of taxes— — — — (20)— — — (20)
Cash dividends declared on common stock ($0.81 per share)
— — — (2,051)— — — — (2,051)
Treasury stock shares purchased— — — — — 13 (1,164)— (1,164)
Share-based compensation plans and other— — 112 — — (1)66 — 178 
Net income attributable to noncontrolling interests— — — — — — — 6 6 
Balance at March 31, 20253,577 $1,788 $44,816 $66,097 $(4,965)1,061 $(59,401)$65 $48,400 
Balance at January 1, 2026
3,577 $1,788 $45,029 $73,075 $(4,287)1,102 $(62,999)$56 $52,662 
Net loss attributable to Merck & Co., Inc.
— — — (4,240)— — — — (4,240)
Other comprehensive income, net of taxes
— — — — 227 — — — 227 
Cash dividends declared on common stock ($0.85 per share)
— — — (2,114)— — — — (2,114)
Treasury stock shares purchased— — — — — 8 (925)— (925)
Share-based compensation plans and other— — 147 — — (3)177 — 324 
Net loss attributable to noncontrolling interests
— — — — — — — (3)(3)
Balance at March 31, 20263,577 $1,788 $45,176 $66,721 $(4,060)1,107 $(63,747)$53 $45,931 
​
v3.26.1
Pension and Other Postretirement Benefit Plans
 3 Months Ended
Mar. 31, 2026
Retirement Benefits [Abstract]  
Pension and Other Postretirement Benefit Plans Pension and Other Postretirement Benefit Plans
The Company has defined benefit pension plans covering eligible employees in the U.S. and in certain of its international subsidiaries. The net periodic benefit cost (credit) of such plans consisted of the following components: 
Three Months Ended
March 31,
20262025
($ in millions)U.S.InternationalU.S.International
Service cost$98 $48 $89 $54 
Interest cost145 81 141 71 
Expected return on plan assets(207)(161)(210)(143)
Amortization of unrecognized prior service credit
— (4)— (4)
Net loss (gain) amortization
27 (1)13 3 
Termination benefits3 15 — — 
 $66 $(22)$33 $(19)
The Company provides medical benefits, principally to its eligible U.S. retirees and similar benefits to their dependents, through its other postretirement benefit plans. The net credit of such plans consisted of the following components: 
Three Months Ended
March 31,
($ in millions)20262025
Service cost$11 $10 
Interest cost16 16 
Expected return on plan assets(14)(14)
Amortization of unrecognized prior service credit(9)(10)
Net gain amortization(8)(10)
Terminations benefits
1 — 
 $(3)$(8)
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 11), 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.
v3.26.1
Other (Income) Expense, Net
 3 Months Ended
Mar. 31, 2026
Other Income and Expenses [Abstract]  
Other (Income) Expense, Net Other (Income) Expense, Net
Other (income) expense, net, consisted of: 
 Three Months Ended
March 31,
($ in millions)20262025
Interest income$(35)$(109)
Interest expense479 313 
Exchange losses38 90 
Income from investments in equity securities, net (1)
(168)(90)
Net periodic defined benefit plan (credit) cost other than service cost(134)(148)
Other, net(42)(91)
 $138 $(35)
(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 owned directly 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 three months ended March 31, 2026 and 2025 was $342 million and $233 million, respectively.
v3.26.1
Income Taxes
 3 Months Ended
Mar. 31, 2026
Income Tax Disclosure [Abstract]  
Income Taxes Income Taxes
The income tax provision of $709 million for the first quarter of 2026 on a pretax loss of $3.5 billion, resulted in an effective income tax rate of (20.1)%. The first quarter 2026 effective income tax rate reflects a 33.1 percentage point unfavorable impact of the charge for the acquisition of Cidara, which had no tax benefit, partially offset by the favorable impacts of jurisdictional mix of income and expense. The effective income tax rate of 13.9% for the first quarter of 2025 reflects the favorable impacts of jurisdictional mix of income and expense, as well as certain discrete items.
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. 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 $260 million. These amounts are exclusive of any interest that may be due. The Company disagrees with the proposed adjustments and will vigorously contest the NOPAs through all available administrative and, if necessary, judicial proceedings. It may take a number of years to reach resolution of this matter. If the Company is ultimately unsuccessful in defending its position, the impact could be material to its financial statements. The statute of limitations for assessments with respect to the 2019 and 2020 federal tax return years expired in June 2024 and October 2024, respectively. The IRS is also currently conducting examinations of the Company’s tax returns for the years 2021 and 2022. In addition, various state and foreign tax examinations are in progress.
v3.26.1
(Loss) Earnings Per Share
 3 Months Ended
Mar. 31, 2026
Earnings Per Share [Abstract]  
(Loss) Earnings Per Share (Loss) Earnings Per Share
The calculations of (loss) earnings per share are as follows:
 Three Months Ended
March 31,
($ and shares in millions except per share amounts)20262025
Net (Loss) Income Attributable to Merck & Co., Inc.
$(4,240)$5,079 
Average common shares outstanding2,472 2,523 
Common shares issuable (1)
— 8 
Average common shares outstanding assuming dilution 2,472 2,531 
Basic (Loss) Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders
$(1.72)$2.01 
(Loss) Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders
$(1.72)$2.01 
(1)    Issuable primarily under share-based compensation plans.
The Company recorded a net loss for the first quarter of 2026; therefore, no potential dilutive common shares were used in the computation of loss per common share assuming dilution because the effect would have been antidilutive. For the first quarter of 2025, 10 million of common shares issuable under share-based compensation plans were excluded from the computation of earnings per common share assuming dilution because the effect would have been antidilutive.
v3.26.1
Other Comprehensive Income (Loss)
 3 Months Ended
Mar. 31, 2026
Equity [Abstract]  
Other Comprehensive Income (Loss) Other Comprehensive Income (Loss)
Changes in each component of other comprehensive income (loss) are as follows:
Three Months Ended March 31,
($ in millions)DerivativesEmployee
Benefit
Plans		Foreign Currency
Translation
Adjustment		Accumulated Other
Comprehensive
Loss
Balance January 1, 2025, net of taxes
$242 $(2,327)$(2,860)$(4,945)
Other comprehensive income (loss) before reclassification adjustments, pretax(201)(1)200 (2)
Tax42 — 15 57 
Other comprehensive income (loss) before reclassification adjustments, net of taxes(159)(1)215 55 
Reclassification adjustments, pretax(73)
(1)
(10)
(2)
— (83)
Tax15 (7)— 8 
Reclassification adjustments, net of taxes(58)

(17)

— (75)
Other comprehensive income (loss), net of taxes(217)(18)215 (20)
Balance March 31, 2025, net of taxes
$25 $(2,345)$(2,645)$(4,965)
Balance January 1, 2026, net of taxes
$(105)$(1,499)$(2,683)$(4,287)
Other comprehensive income (loss) before reclassification adjustments, pretax168 1 15 184 
Tax(35)1 (9)(43)
Other comprehensive income (loss) before reclassification adjustments, net of taxes133 2 6 141 
Reclassification adjustments, pretax105 
(1)
5 
(2)
— 110 
Tax(22)(2)— (24)
Reclassification adjustments, net of taxes83 

3 

— 86 
Other comprehensive income (loss), net of taxes216 5 6 227 
Balance March 31, 2026, net of taxes
$111 $(1,494)$(2,677)$(4,060)
(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 10).
v3.26.1
Segment Reporting
 3 Months Ended
Mar. 31, 2026
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 March 31,
20262025
 ($ in millions)U.S.Int’lTotalU.S.Int’lTotal
Pharmaceutical:
Oncology
Keytruda$4,599 $3,307 $7,906 $4,308 $2,897 $7,205 
Keytruda Qlex
106 21 128 — — — 
Alliance revenue-Lynparza (1)
149 192 341 145 168 312 
Alliance revenue-Lenvima (1)
176 80 256 186 72 258 
Welireg152 47 199 123 15 137 
Alliance revenue-Reblozyl (2)
128 20 148 101 18 119 
Vaccines
Gardasil/Gardasil 9
485 585 1,069 536 790 1,327 
ProQuad/M-M-R II/Varivax
409 129 538 423 116 539 
RotaTeq165 42 206 164 64 228 
Vaxneuvance123 78 202 139 92 230 
Capvaxive
118 23 142 106 1 107 
Cardiometabolic and Respiratory
Winrevair
477 48 525 268 12 280 
Ohtuvayre
131 — 131 — — — 
Alliance revenue-Adempas/Verquvo (3)
109 — 109 97 9 106 
Adempas— 78 78 — 68 68 
Infectious Diseases
Bridion427 45 472 378 63 441 
Prevymis135 138 272 102 106 208 
Zerbaxa52 30 82 42 28 70 
Delstrigo
10 65 75 15 52 67 
Isentress/Isentress HD
35 24 59 51 39 90 
Dificid24 10 34 72 11 83 
Lagevrio16 12 28 35 67 102 
Diabetes
Januvia252 116 367 344 204 549 
Janumet68 139 207 65 182 247 
Other pharmaceutical (4)
166 608 775 227 637 865 
Total Pharmaceutical segment sales8,512 5,837 14,349 7,927 5,711 13,638 
Animal Health:
Livestock211 853 1,064 194 730 924 
Companion Animal308 419 727 308 356 664 
Total Animal Health segment sales519 1,272 1,791 502 1,086 1,588 
Total segment sales9,031 7,109 16,140 8,429 6,797 15,226 
Other (5)
133 13 146 93 210 303 
 $9,164 $7,122 $16,286 $8,522 $7,007 $15,529 
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. Also reflects total alliance revenue for Koselugo of $161 million and $44 million in the first quarter of 2026 and 2025, respectively (see Note 3).
(5)    Other is primarily comprised of miscellaneous corporate revenue, including revenue hedging activities which (decreased) increased sales by $(110) million and $58 million for the three months ended March 31, 2026 and 2025, respectively, as well as revenue from third-party manufacturing arrangements (including sales to Organon & Co.). Other for the three months ended March 31, 2026 and 2025 also includes $132 million and $95 million, respectively, related to 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 $2.1 billion for the three months ended March 31, 2026 and 2025, respectively.
Consolidated sales by geographic area where derived are as follows:
Three Months Ended
March 31,
($ in millions)20262025
United States$9,164 $8,522 
Europe, Middle East and Africa3,886 3,454 
Latin America874 792 
Asia Pacific (other than China and Japan)738 689 
Japan555 669 
China390 702 
Other679 701 
 $16,286 $15,529 
A reconciliation of segment profits to (Loss) Income Before Taxes is as follows:
Three Months Ended March 31,
20262025
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
Total
Segment sales$14,349 $1,791 $16,140 $13,638 $1,588 $15,226 
Less segment costs: (1)
Cost of sales1,553 675 1,573 600 
Selling, general and administrative1,332 282 1,402 260 
Research and development (2)
— 112 — 95 
Other segment items (3)
(55)— (49)(1)
Total segment profits$11,519 $722 $12,241 $10,712 $634 $11,346 
Other profits106 202 
Unallocated:
Interest income35 109 
Interest expense(479)(313)
Amortization(931)(597)
Depreciation(491)(441)
Research and development(12,404)(3,477)
Restructuring costs(195)(69)
Other unallocated, net(1,416)(857)
$(3,534)$5,903 
(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 consist of segment sales less standard costs, as well as selling, general and administrative expenses directly incurred by the segment. Animal Health segment profits consist 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 for the purpose of evaluating performance, allocating resources, informing incentive compensation targets and setting strategic Company goals during the planning and forecasting process. On a quarterly basis, the CEO considers forecast-to-actual variances in segment profit when assessing performance of the segments and making decisions about allocating resources to the segments. 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 the recognition of fair value step-up of inventories 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 March 31,
20262025
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
Total
Equity income from affiliates
$62 $— $62 $58 $— $58 
Depreciation
1 89 90 1 60 61 
Property, plant and equipment, net, by geographic area where located is as follows:
($ in millions)
March 31, 2026December 31, 2025
United States$15,097 $15,021 
Europe, Middle East and Africa8,966 8,856 
Asia Pacific (other than China and Japan)
842 898 
China213 218 
Japan136 144 
Latin America128 128 
Other51 51 
$25,433 $25,316 
The Company does not disaggregate assets on a products and services basis for internal management reporting and, therefore, such information is not presented.
v3.26.1
Insider Trading Arrangements
 3 Months Ended
Mar. 31, 2026
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
v3.26.1
Basis of Presentation (Policies)
 3 Months Ended
Mar. 31, 2026
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 24, 2026.
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 November 2024, the Financial Accounting Standards Board (FASB) issued guidance intended to improve financial reporting by requiring entities to disclose additional information about specific expense categories for 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.
In December 2025, the FASB issued guidance that includes requirements for recognition of government grants in a company’s financial statements as well as disclosure requirements, including the nature of the government grant received, the accounting policies used to account for the grant, and significant terms and conditions of the grant. The guidance is effective for 2029 interim and annual reporting on a modified prospective, modified retrospective or retrospective approach. Early adoption is permitted as of the beginning of an annual reporting period. The Company is currently evaluating the impact of adoption on its consolidated financial statements.
Legal Costs Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable.
v3.26.1
Collaborative Arrangements (Tables)
 3 Months Ended
Mar. 31, 2026
Collaborative Arrangements [Abstract]  
Schedule of Collaboration Arrangements
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Alliance revenue - Lynparza$341 $312 
Alliance revenue - Koselugo (1)
161 44 
Total alliance revenue$502 $356 
Cost of sales (2)
84 83 
Selling, general and administrative24 32 
Research and development5 12 
($ in millions)March 31, 2026December 31, 2025
Receivables from AstraZeneca included in Other current assets (3)
$401 $451 
Receivables from AstraZeneca included in Other assets (3)
125 125 
Payables to AstraZeneca included in Accrued and other current liabilities
12 6 
(1)    Amount in the first quarter of 2026 includes $150 million related to the amendment of the collaboration agreement noted above.
(2)    Represents amortization of capitalized milestone payments.
(3)    Includes milestone receivables.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Alliance revenue - Lenvima$256 $258 
Cost of sales (1)
13 60 
Selling, general and administrative27 31 
Research and development2 5 
($ in millions)March 31, 2026December 31, 2025
Receivables from Eisai included in Other current assets
$252 $271 
(1)    Represents amortization of capitalized milestone payments.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Alliance revenue - Adempas/Verquvo$109 $106 
Net sales of Adempas recorded by Merck78 68 
Net sales of Verquvo recorded by Merck9 9 
Total sales$196 $183 
Cost of sales (1)
67 58 
Selling, general and administrative12 29 
Research and development17 24 
($ in millions)March 31, 2026December 31, 2025
Receivables from Bayer included in Other current assets
$162 $167 
Payables to Bayer included in Accrued and other current liabilities
87 81 
(1)    Includes amortization of intangible assets, cost of products sold by Merck, as well as Bayer’s share of profits from sales in Merck’s marketing territories.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Net sales of Lagevrio recorded by Merck
$28 $102 
Cost of sales (1)
54 53 
Selling, general and administrative
11 13 
Research and development
5 8 
(1)    Includes cost of products sold by Merck, Ridgeback’s share of profits, royalty expense, amortization of capitalized milestone payments and inventory reserves.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Selling, general and administrative $12 $9 
Research and development
160 128 
($ in millions)March 31, 2026December 31, 2025
Receivables from Daiichi Sankyo included in Other current assets
$22 $15 
Payables to Daiichi Sankyo included in Accrued and other current liabilities
85 113 
Summarized financial information related to this collaboration is as follows:
Three Months Ended
March 31,
($ in millions)20262025
Selling, general and administrative $8 $6 
Research and development (1)
90 86 
($ in millions)March 31, 2026December 31, 2025
Receivables from Moderna included in Other current assets
$4 $— 
Payables to Moderna included in Accrued and other current liabilities
— 13 
(1)    Includes amortization of shared facility costs.
v3.26.1
Restructuring (Tables)
 3 Months Ended
Mar. 31, 2026
Restructuring and Related Activities [Abstract]  
Schedule of Charges Related to Restructuring Program Activities by Type of Cost
The following tables summarize the charges related to restructuring program activities by type of cost:
 Three Months Ended March 31, 2026
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
2025 Restructuring Program
Cost of sales$12 $— $132 $144 
Research and development— — 34 34 
Restructuring costs— 123 17 140 
12 123 183 318 
2024 Restructuring Program
Cost of sales96 — (3)93 
Restructuring costs— — 55 55 
96 — 52 148 
$108 $123 $235 $466 
 Three Months Ended March 31, 2025
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
2024 Restructuring Program
Cost of sales$41 $— $(5)$36 
Restructuring costs— 1 68 69 
$41 $1 $63 $105 
Schedule of Charges and Spending Relating to Restructuring Activities by Program
The following table summarizes the charges and spending related to restructuring program activities for the three months ended March 31, 2026:
($ in millions)
Accelerated Depreciation
Separation
Costs
Other Exit Costs
Total
2025 Restructuring Program
Restructuring reserves January 1, 2026
$— $502 $288 $790 
Expenses
12 123 183 318 
(Payments) receipts, net— (156)(166)(322)
Non-cash activity(12)(9)(117)(138)
Restructuring reserves March 31, 2026
$— $460 $188 $648 
2024 Restructuring Program
Restructuring reserves January 1, 2026
$— $506 $— $506 
Expenses96 — 52 148 
(Payments) receipts, net— (70)(53)(123)
Non-cash activity(96)12 1 (83)
Restructuring reserves March 31, 2026
$— $448 $— $448 
v3.26.1
Financial Instruments (Tables)
 3 Months Ended
Mar. 31, 2026
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of Effect of Net Investment Hedges on OCI and the Consolidated Statement of Operations
The effects of the Company’s net investment hedges on OCI and the Condensed Consolidated Statement of Income are shown below:
Amount of Pretax (Gain) Loss Recognized in Other Comprehensive Income (1)
Amount of Pretax Gain Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing
Three Months Ended March 31,Three Months Ended March 31,
($ in millions)2026202520262025
Net Investment Hedging Relationships
Foreign exchange contracts$(15)$27 $(4)$(3)
Euro-denominated notes(137)130 — — 
(1)    No amounts were reclassified from AOCL into income related to the sale of a subsidiary.
Schedule of Interest Rate Swaps Held
At March 31, 2026, the Company was a party to ten 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.
March 31, 2026
($ in millions)
Par Value of Debt
Number of Interest Rate Swaps Held
Total Swap Notional Amount
4.50% notes due 2033
$1,500 6 $1,500 
4.75% notes due 2035
1,500 2 500 
5.00% notes due 2053
1,500 2 500 
Schedule of Amounts Recorded on Balance Sheet Related to Fair Value Hedges
The table below presents the location of amounts recorded in the Condensed Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges:
Carrying Amount of Hedged Liabilities
Cumulative Amount of Fair Value Hedging Adjustment Increase Included in the Carrying Amount
($ in millions)
March 31, 2026December 31, 2025March 31, 2026December 31, 2025
Balance Sheet Caption
Long-Term Debt
$2,539 $1,810 $57 $70 
Schedule of Fair Value of Derivatives on a Gross Basis Segregated between those Derivatives that are Designated as Hedging Instruments and those that are Not Designated as Hedging Instruments
Presented in the table below is the fair value of derivatives on a gross basis segregated between those derivatives that are designated as hedging instruments and those that are not designated as hedging instruments:
  March 31, 2026December 31, 2025
  Fair Value of DerivativeU.S. Dollar
Notional		Fair Value of DerivativeU.S. Dollar
Notional
($ in millions)AssetLiabilityAssetLiability
Derivatives Designated as Hedging InstrumentsBalance Sheet Caption
Interest rate swap contracts
Other Assets
$58 $— $2,500 $71 $— $1,750 
Interest rate contracts
Other Assets
8 — 500 — — — 
Foreign exchange contractsOther current assets247 — 7,751 113 — 6,430 
Foreign exchange contractsOther Assets55 — 1,828 32 — 1,793 
Foreign exchange contractsAccrued and other current liabilities— 48 3,705 — 131 4,726 
Foreign exchange contractsOther Noncurrent Liabilities— 1 33 — 1 13 
  $368 $49 $16,317 $216 $132 $14,712 
Derivatives Not Designated as Hedging InstrumentsBalance Sheet Caption      
Foreign exchange contractsOther current assets$194 $— $13,870 $107 $— $11,643 
Foreign exchange contractsAccrued and other current liabilities— 180 11,919 — 191 13,579 
Foreign exchange contracts
Other Noncurrent Liabilities
— — — — 1 357 
  $194 $180 $25,789 $107 $192 $25,579 
  $562 $229 $42,106 $323 $324 $40,291 
Schedule of Information on Derivative Positions Subject to Master Netting Arrangements as if they were Presented on a Net Basis The following table provides information on the Company’s derivative positions subject to these master netting arrangements as if they were presented on a net basis, allowing for the right of offset by counterparty and cash collateral exchanged per the master agreements and related credit support annexes:
 March 31, 2026December 31, 2025
($ in millions)AssetLiabilityAssetLiability
Gross amounts recognized in the condensed consolidated balance sheet$562 $229 $323 $324 
Gross amounts subject to offset in master netting arrangements not offset in the condensed consolidated balance sheet(225)(225)(245)(245)
Cash collateral received
(89)— (1)— 
Net amounts$248 $4 $77 $79 
Schedule of Location and Amount of Pretax Gains and Losses of Derivatives
The table below provides information regarding the location and amount of pretax gains and losses of derivatives designated in fair value or cash flow hedging relationships:
Three Months Ended March 31,
($ in millions)202620252026202520262025
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)
$16,286 $15,529 $138 $(35)$227 $(20)
(Gain) loss on fair value hedging relationships:
Interest rate swap contracts
Hedged items— — (14)38 — — 
Derivatives designated as hedging instruments— — 13 (39)— — 
Impact of cash flow hedging relationships:
Foreign exchange contracts
Amount of gain (loss) recognized in OCI on derivatives
— — — — 168 (201)
(Decrease) increase in Sales as a result of AOCL reclassifications
(98)74 — — 98 (74)
Interest rate contracts
Amount of gain recognized in Other (income) expense, net on derivatives
— — (1)— — — 
Amount of gain recognized in OCI on derivatives
— — — — 7 — 
(1)    Interest expense is a component of Other (income) expense, net.
Schedule of Income Statement Effects of Derivatives Not Designated as Hedging Instruments
The table below provides information regarding the income statement effects of derivatives not designated as hedging instruments:
Amount of Derivative Pretax Loss (Gain) Recognized in Income
Three Months Ended March 31,
($ in millions)20262025
Derivatives Not Designated as Hedging InstrumentsIncome Statement Caption
Foreign exchange contracts (1)
Other (income) expense, net$36 $(20)
Foreign exchange contracts (2)
Sales12 16 
(1)    These derivative contracts primarily mitigate changes in the value of remeasured foreign currency denominated monetary assets and liabilities attributable to changes in foreign currency exchange rates.
(2)    These derivative contracts serve as economic hedges of forecasted transactions.
Schedule of Information on Investments in Debt and Equity Securities
Information on investments in debt and equity securities is as follows:
 March 31, 2026December 31, 2025
 Amortized
Cost		Gross UnrealizedFair
Value		Amortized
Cost		Gross UnrealizedFair
Value
($ in millions)GainsLossesGainsLosses
Commercial paper$375 $— $— $375 $— $— $— $— 
U.S. government and agency securities100 — — 100 100 — — 100 
Foreign government bonds
1 — — 1 1 — — 1 
Total debt securities$476 $— $— $476 $101 $— $— $101 
Publicly traded equity securities (1)
1,571 1,392 
Total debt and publicly traded equity securities$2,047 $1,493 
(1)    Unrealized net gains of $126 million were recorded in Other (income) expense, net in the first quarter of 2026 on equity securities still held at March 31, 2026. Unrealized net gains of $115 million were recorded in Other (income) expense, net in the first quarter of 2025 on equity securities still held at March 31, 2025.
Schedule of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis
Financial assets and liabilities measured at fair value on a recurring basis are summarized below:
Fair Value Measurements UsingFair Value Measurements Using
 Level 1Level 2Level 3TotalLevel 1Level 2Level 3Total
($ in millions)March 31, 2026December 31, 2025
Assets
Investments
Commercial paper$— $375 $— $375 $— $— $— $— 
Foreign government bonds
— 1 — 1 — 1 — 1 
Publicly traded equity securities1,104 — — 1,104 955 — — 955 
 1,104 376 — 1,480 955 1 — 956 
Other assets (1)
U.S. government and agency securities100 — — 100 100 — — 100 
Publicly traded equity securities (2)
467 — — 467 437 — — 437 
567 — — 567 537 — — 537 
Derivative assets (3)
Forward exchange contracts— 310 — 310 — 168 — 168 
Purchased currency options— 186 — 186 — 84 — 84 
Interest rate swaps
— 58 — 58 — 71 — 71 
Interest rate contracts
— 8 — 8 — — — — 
 — 562 — 562 — 323 — 323 
Total assets$1,671 $938 $— $2,609 $1,492 $324 $— $1,816 
Liabilities
Derivative liabilities (3)
Forward exchange contracts$— $202 $— $202 $— $293 $— $293 
Written currency options— 27 — 27 — 31 — 31 
Total liabilities$— $229 $— $229 $— $324 $— $324 
(1)    Investments included in other assets are restricted as to use, including for the payment of benefits under employee benefit plans.
(2)    Balance at March 31, 2026 includes securities with a fair value of $17 million that are subject to a contractual sale restriction that expires in July 2026, and securities with a fair value of $18 million that are subject to a contractual sale restriction that expires in August 2026.
(3)    The fair value determination of derivatives includes the impact of the credit risk of counterparties to the derivatives and the Company’s own credit risk, the effects of which were not significant.
v3.26.1
Inventories (Tables)
 3 Months Ended
Mar. 31, 2026
Inventory Disclosure [Abstract]  
Schedule of Inventory, current
Inventories consisted of:
($ in millions)March 31, 2026December 31, 2025
Finished goods$2,211 $2,275 
Raw materials and work in process11,136 10,645 
Supplies334 331 
Total13,681 13,251 
Decrease to LIFO cost(1,007)(912)
 $12,674 $12,339 
Recognized as:
Inventories$6,479 $6,658 
Other Assets6,195 5,681 
Schedule of Inventory, noncurrent
Inventories consisted of:
($ in millions)March 31, 2026December 31, 2025
Finished goods$2,211 $2,275 
Raw materials and work in process11,136 10,645 
Supplies334 331 
Total13,681 13,251 
Decrease to LIFO cost(1,007)(912)
 $12,674 $12,339 
Recognized as:
Inventories$6,479 $6,658 
Other Assets6,195 5,681 
v3.26.1
Equity (Tables)
 3 Months Ended
Mar. 31, 2026
Equity [Abstract]  
Schedule of Equity
Three Months Ended March 31,
   Common StockOther
Paid-In
Capital		Retained
Earnings		Accumulated
Other
Comprehensive
Loss		 Treasury StockNon-
controlling
Interests		Total
($ and shares in millions except per share amounts)SharesPar ValueSharesCost
Balance at January 1, 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.
— — — 5,079 — — — — 5,079 
Other comprehensive loss, net of taxes— — — — (20)— — — (20)
Cash dividends declared on common stock ($0.81 per share)
— — — (2,051)— — — — (2,051)
Treasury stock shares purchased— — — — — 13 (1,164)— (1,164)
Share-based compensation plans and other— — 112 — — (1)66 — 178 
Net income attributable to noncontrolling interests— — — — — — — 6 6 
Balance at March 31, 20253,577 $1,788 $44,816 $66,097 $(4,965)1,061 $(59,401)$65 $48,400 
Balance at January 1, 2026
3,577 $1,788 $45,029 $73,075 $(4,287)1,102 $(62,999)$56 $52,662 
Net loss attributable to Merck & Co., Inc.
— — — (4,240)— — — — (4,240)
Other comprehensive income, net of taxes
— — — — 227 — — — 227 
Cash dividends declared on common stock ($0.85 per share)
— — — (2,114)— — — — (2,114)
Treasury stock shares purchased— — — — — 8 (925)— (925)
Share-based compensation plans and other— — 147 — — (3)177 — 324 
Net loss attributable to noncontrolling interests
— — — — — — — (3)(3)
Balance at March 31, 20263,577 $1,788 $45,176 $66,721 $(4,060)1,107 $(63,747)$53 $45,931 
​
v3.26.1
Pension and Other Postretirement Benefit Plans (Tables)
 3 Months Ended
Mar. 31, 2026
Pension Plans  
Defined Benefit Plan Disclosure [Line Items]  
Schedule of Net Benefit Costs
The Company has defined benefit pension plans covering eligible employees in the U.S. and in certain of its international subsidiaries. The net periodic benefit cost (credit) of such plans consisted of the following components: 
Three Months Ended
March 31,
20262025
($ in millions)U.S.InternationalU.S.International
Service cost$98 $48 $89 $54 
Interest cost145 81 141 71 
Expected return on plan assets(207)(161)(210)(143)
Amortization of unrecognized prior service credit
— (4)— (4)
Net loss (gain) amortization
27 (1)13 3 
Termination benefits3 15 — — 
 $66 $(22)$33 $(19)
Other Postretirement Benefit Plans  
Defined Benefit Plan Disclosure [Line Items]  
Schedule of Net Benefit Costs
The Company provides medical benefits, principally to its eligible U.S. retirees and similar benefits to their dependents, through its other postretirement benefit plans. The net credit of such plans consisted of the following components: 
Three Months Ended
March 31,
($ in millions)20262025
Service cost$11 $10 
Interest cost16 16 
Expected return on plan assets(14)(14)
Amortization of unrecognized prior service credit(9)(10)
Net gain amortization(8)(10)
Terminations benefits
1 — 
 $(3)$(8)
v3.26.1
Other (Income) Expense, Net (Tables)
 3 Months Ended
Mar. 31, 2026
Other Income and Expenses [Abstract]  
Schedule of Other (Income) Expense, Net
Other (income) expense, net, consisted of: 
 Three Months Ended
March 31,
($ in millions)20262025
Interest income$(35)$(109)
Interest expense479 313 
Exchange losses38 90 
Income from investments in equity securities, net (1)
(168)(90)
Net periodic defined benefit plan (credit) cost other than service cost(134)(148)
Other, net(42)(91)
 $138 $(35)
(1)    Includes net realized and unrealized gains and losses from investments in equity securities either owned directly or through ownership interests in investment funds. Unrealized gains and losses from investments that are owned directly are determined at the end of the reporting period, while gains and losses from ownership interests in investment funds are accounted for on a one quarter lag.
v3.26.1
(Loss) Earnings Per Share (Tables)
 3 Months Ended
Mar. 31, 2026
Earnings Per Share [Abstract]  
Schedule of Calculations of Earnings Per Share
The calculations of (loss) earnings per share are as follows:
 Three Months Ended
March 31,
($ and shares in millions except per share amounts)20262025
Net (Loss) Income Attributable to Merck & Co., Inc.
$(4,240)$5,079 
Average common shares outstanding2,472 2,523 
Common shares issuable (1)
— 8 
Average common shares outstanding assuming dilution 2,472 2,531 
Basic (Loss) Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders
$(1.72)$2.01 
(Loss) Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders
$(1.72)$2.01 
(1)    Issuable primarily under share-based compensation plans.
v3.26.1
Other Comprehensive Income (Loss) (Tables)
 3 Months Ended
Mar. 31, 2026
Equity [Abstract]  
Schedule of Changes in AOCI by Component
Changes in each component of other comprehensive income (loss) are as follows:
Three Months Ended March 31,
($ in millions)DerivativesEmployee
Benefit
Plans		Foreign Currency
Translation
Adjustment		Accumulated Other
Comprehensive
Loss
Balance January 1, 2025, net of taxes
$242 $(2,327)$(2,860)$(4,945)
Other comprehensive income (loss) before reclassification adjustments, pretax(201)(1)200 (2)
Tax42 — 15 57 
Other comprehensive income (loss) before reclassification adjustments, net of taxes(159)(1)215 55 
Reclassification adjustments, pretax(73)
(1)
(10)
(2)
— (83)
Tax15 (7)— 8 
Reclassification adjustments, net of taxes(58)

(17)

— (75)
Other comprehensive income (loss), net of taxes(217)(18)215 (20)
Balance March 31, 2025, net of taxes
$25 $(2,345)$(2,645)$(4,965)
Balance January 1, 2026, net of taxes
$(105)$(1,499)$(2,683)$(4,287)
Other comprehensive income (loss) before reclassification adjustments, pretax168 1 15 184 
Tax(35)1 (9)(43)
Other comprehensive income (loss) before reclassification adjustments, net of taxes133 2 6 141 
Reclassification adjustments, pretax105 
(1)
5 
(2)
— 110 
Tax(22)(2)— (24)
Reclassification adjustments, net of taxes83 

3 

— 86 
Other comprehensive income (loss), net of taxes216 5 6 227 
Balance March 31, 2026, net of taxes
$111 $(1,494)$(2,677)$(4,060)
(1)    Primarily relates to foreign currency cash flow hedges that were reclassified from AOCL to Sales.
(2)    Includes net amortization of prior service cost, actuarial gains and losses, settlements and curtailments included in net periodic benefit cost (see Note 10).
v3.26.1
Segment Reporting (Tables)
 3 Months Ended
Mar. 31, 2026
Segment Reporting [Abstract]  
Schedule of Sales from Products
Sales of the Company’s products were as follows:
Three Months Ended March 31,
20262025
 ($ in millions)U.S.Int’lTotalU.S.Int’lTotal
Pharmaceutical:
Oncology
Keytruda$4,599 $3,307 $7,906 $4,308 $2,897 $7,205 
Keytruda Qlex
106 21 128 — — — 
Alliance revenue-Lynparza (1)
149 192 341 145 168 312 
Alliance revenue-Lenvima (1)
176 80 256 186 72 258 
Welireg152 47 199 123 15 137 
Alliance revenue-Reblozyl (2)
128 20 148 101 18 119 
Vaccines
Gardasil/Gardasil 9
485 585 1,069 536 790 1,327 
ProQuad/M-M-R II/Varivax
409 129 538 423 116 539 
RotaTeq165 42 206 164 64 228 
Vaxneuvance123 78 202 139 92 230 
Capvaxive
118 23 142 106 1 107 
Cardiometabolic and Respiratory
Winrevair
477 48 525 268 12 280 
Ohtuvayre
131 — 131 — — — 
Alliance revenue-Adempas/Verquvo (3)
109 — 109 97 9 106 
Adempas— 78 78 — 68 68 
Infectious Diseases
Bridion427 45 472 378 63 441 
Prevymis135 138 272 102 106 208 
Zerbaxa52 30 82 42 28 70 
Delstrigo
10 65 75 15 52 67 
Isentress/Isentress HD
35 24 59 51 39 90 
Dificid24 10 34 72 11 83 
Lagevrio16 12 28 35 67 102 
Diabetes
Januvia252 116 367 344 204 549 
Janumet68 139 207 65 182 247 
Other pharmaceutical (4)
166 608 775 227 637 865 
Total Pharmaceutical segment sales8,512 5,837 14,349 7,927 5,711 13,638 
Animal Health:
Livestock211 853 1,064 194 730 924 
Companion Animal308 419 727 308 356 664 
Total Animal Health segment sales519 1,272 1,791 502 1,086 1,588 
Total segment sales9,031 7,109 16,140 8,429 6,797 15,226 
Other (5)
133 13 146 93 210 303 
 $9,164 $7,122 $16,286 $8,522 $7,007 $15,529 
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. Also reflects total alliance revenue for Koselugo of $161 million and $44 million in the first quarter of 2026 and 2025, respectively (see Note 3).
(5)    Other is primarily comprised of miscellaneous corporate revenue, including revenue hedging activities which (decreased) increased sales by $(110) million and $58 million for the three months ended March 31, 2026 and 2025, respectively, as well as revenue from third-party manufacturing arrangements (including sales to Organon & Co.). Other for the three months ended March 31, 2026 and 2025 also includes $132 million and $95 million, respectively, related to milestone payments received by Merck for out-licensing arrangements.
Schedule of Consolidated Sales by Geographic Area
Consolidated sales by geographic area where derived are as follows:
Three Months Ended
March 31,
($ in millions)20262025
United States$9,164 $8,522 
Europe, Middle East and Africa3,886 3,454 
Latin America874 792 
Asia Pacific (other than China and Japan)738 689 
Japan555 669 
China390 702 
Other679 701 
 $16,286 $15,529 
Schedule of Reconciliation of Segment Profits to Income before Taxes
A reconciliation of segment profits to (Loss) Income Before Taxes is as follows:
Three Months Ended March 31,
20262025
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
Total
Segment sales$14,349 $1,791 $16,140 $13,638 $1,588 $15,226 
Less segment costs: (1)
Cost of sales1,553 675 1,573 600 
Selling, general and administrative1,332 282 1,402 260 
Research and development (2)
— 112 — 95 
Other segment items (3)
(55)— (49)(1)
Total segment profits$11,519 $722 $12,241 $10,712 $634 $11,346 
Other profits106 202 
Unallocated:
Interest income35 109 
Interest expense(479)(313)
Amortization(931)(597)
Depreciation(491)(441)
Research and development(12,404)(3,477)
Restructuring costs(195)(69)
Other unallocated, net(1,416)(857)
$(3,534)$5,903 
(1)    The significant expense categories and amounts align with the segment level information that is regularly provided to the chief operating decision maker.
(2)    Human health-related research and development expenses incurred by Merck Research Laboratories are not allocated to segment profits as noted below.
(3)    Includes equity (income) loss from affiliates and other miscellaneous non-operating expenses.
Schedule of Equity Loss from Affiliates and Depreciation Included in Segment Profits
Equity income from affiliates and depreciation included in segment profits is as follows:
Three Months Ended March 31,
20262025
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
Total
Equity income from affiliates
$62 $— $62 $58 $— $58 
Depreciation
1 89 90 1 60 61 
Schedule of Property, Plant and Equipment, Net by Geographic Area
Property, plant and equipment, net, by geographic area where located is as follows:
($ in millions)
March 31, 2026December 31, 2025
United States$15,097 $15,021 
Europe, Middle East and Africa8,966 8,856 
Asia Pacific (other than China and Japan)
842 898 
China213 218 
Japan136 144 
Latin America128 128 
Other51 51 
$25,433 $25,316 
v3.26.1
Acquisitions, Research Collaborations and Licensing Agreements (Details) - USD ($)
$ / shares in Units, $ in Millions
 1 Months Ended 3 Months Ended
May 31, 2026
Mar. 31, 2026
Jan. 31, 2026
Mar. 31, 2025
Dec. 31, 2026
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Business Combination [Line Items]                
Charge for research and development asset acquisition           $ 8,540 $ 0  
Property, plant and equipment, net   $ 25,433       $ 25,433   $ 25,316
Terns Pharmaceuticals, Inc.                
Business Combination [Line Items]                
Asset acquisition price per share   $ 53       $ 53    
Consideration transferred, asset acquisition   $ 6,700            
Terns Pharmaceuticals, Inc. | Forecast                
Business Combination [Line Items]                
Charge for research and development asset acquisition $ 5,800              
Cidara Therapeutics, Inc.                
Business Combination [Line Items]                
Consideration transferred, asset acquisition     $ 9,200          
Charge for research and development asset acquisition           $ 9,000    
Payments to settle share-based equity awards     570          
Asset acquisition, consideration transferred, settlement of unvested share-based payment awards     406          
Net assets acquired           332    
Future regulatory milestone payments (up to)     105          
Maximum aggregate sales-based milestone payments     $ 455          
sac-TMT                
Business Combination [Line Items]                
Research and development arrangement, contract to perform for others, compensation earned           $ 200    
sac-TMT | Forecast                
Business Combination [Line Items]                
Research and development arrangement, contract to perform for others, compensation earned         $ 700      
WuXi Vaccines' facility                
Business Combination [Line Items]                
Consideration transferred, asset acquisition       $ 437        
WuXi Vaccines' facility | Asset under Construction                
Business Combination [Line Items]                
Property, plant and equipment, net       $ 759     $ 759  
v3.26.1
Collaborative Arrangements - AstraZeneca PLC - Narrative (Details) - USD ($)
 1 Months Ended 3 Months Ended
Feb. 28, 2026
Sep. 30, 2028
Mar. 31, 2028
Sep. 30, 2027
Mar. 31, 2027
Sep. 30, 2026
Mar. 31, 2026
Sep. 30, 2025
Mar. 31, 2025
Dec. 31, 2025
Lynparza | Licenses and Other                    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                    
Finite-lived intangible assets             $ 762,000,000      
Koselugo | Licenses and Other                    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                    
Finite-lived intangible assets             36,000,000      
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement                    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                    
Upfront payments recognized as revenue             150,000,000      
Sales based milestone payments                 $ 700,000,000  
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Alliance revenue - Koselugo                    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                    
Upfront payments recognized as revenue $ 150,000,000             $ 150,000,000    
Sales milestone payments             $ 235,000,000      
Aggregate, regulatory milestones payments, maximum                   $ 175,000,000
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Alliance revenue - Koselugo | Forecast                    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                    
Future fixed upfront payments received     $ 100,000,000   $ 150,000,000          
Collaborative arrangement, milestone payment   $ 75,000,000   $ 50,000,000   $ 50,000,000        
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Lynparza                    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                    
Sales milestone payments                 2,000,000,000.0  
Sales based milestone payments                 600,000,000  
Aggregate, regulatory milestones payments, maximum                 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  
v3.26.1
Collaborative Arrangements - AstraZeneca PLC (Details) - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended
Feb. 28, 2026
Mar. 31, 2026
Sep. 30, 2025
Mar. 31, 2025
Dec. 31, 2025
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Cost of sales   $ 4,195   $ 3,419  
Selling, general and administrative   2,700   2,552  
Research and development   12,592   3,621  
Other current assets   35,015     $ 43,516
Accrued and other current liabilities   14,549     14,468
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Revenue from collaborative arrangement   502   356  
Cost of sales   84   83  
Selling, general and administrative   24   32  
Research and development   5   12  
Other current assets   401     451
Other assets   125     125
Accrued and other current liabilities   12     $ 6
Upfront payments recognized as revenue   150      
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   341   312  
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   $ 161   $ 44  
Upfront payments recognized as revenue $ 150   $ 150    
v3.26.1
Collaborative Arrangements - Eisai Co., Ltd. - Narrative (Details) - Alliance revenue - Lenvima
Mar. 31, 2026
USD ($)
Licenses and Other  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]  
Finite-lived intangible assets $ 188,000,000
Eisai | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]  
Sales milestone payments 2,300,000,000
Aggregate, regulatory milestones payments, maximum $ 0
v3.26.1
Collaborative Arrangements - Eisai Co., Ltd. (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Cost of sales $ 4,195 $ 3,419  
Selling, general and administrative 2,700 2,552  
Research and development 12,592 3,621  
Other current assets 35,015   $ 43,516
Eisai | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Revenue from collaborative arrangement 256 258  
Cost of sales 13 60  
Selling, general and administrative 27 31  
Research and development 2 $ 5  
Other current assets $ 252   $ 271
v3.26.1
Collaborative Arrangements - Bayer AG (Details) - USD ($)
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Sales $ 16,286,000,000 $ 15,529,000,000  
Cost of sales 4,195,000,000 3,419,000,000  
Selling, general and administrative 2,700,000,000 2,552,000,000  
Research and development 12,592,000,000 3,621,000,000  
Other current assets 35,015,000,000   $ 43,516,000,000
Accrued and other current liabilities 14,549,000,000   14,468,000,000
Adempas | Licenses and Other      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Finite-lived intangible assets 239,000,000    
Verquvo | Licenses and Other      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Finite-lived intangible assets 37,000,000    
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Sales milestone payments 0    
Revenue from collaborative arrangement 109,000,000 106,000,000  
Sales 196,000,000 183,000,000  
Cost of sales 67,000,000 58,000,000  
Selling, general and administrative 12,000,000 29,000,000  
Research and development 17,000,000 24,000,000  
Other current assets 162,000,000   167,000,000
Accrued and other current liabilities 87,000,000   $ 81,000,000
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Adempas      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Sales 78,000,000 68,000,000  
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Verquvo      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Sales $ 9,000,000 $ 9,000,000  
v3.26.1
Collaborative Arrangements - Ridgeback Biotherapeutics LP (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Sales $ 16,286 $ 15,529
Cost of sales 4,195 3,419
Selling, general and administrative 2,700 2,552
Ridgeback Biotherapeutics LP | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Cost of sales 54 53
Selling, general and administrative 11 13
Research and development 5 8
Ridgeback Biotherapeutics LP | Lagevrio | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Sales $ 28 $ 102
v3.26.1
Collaborative Arrangements - Daiicho Sankyo - Narrative (Details) - Daiichi Sankyo - Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
$ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
Oct. 31, 2025
USD ($)
Oct. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
candidate
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
Sales based royalty percentage 5.00%     5.00%
Upfront cash payment $ 170      
Ifinatamab Deruxtecan        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]        
Refundable upfront payments in collaborative arrangement       $ 500
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  
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
v3.26.1
Collaborative Arrangements - Schedule of Daiicho Sankyo (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Selling, general and administrative $ 2,700 $ 2,552  
Research and development 12,592 3,621  
Other current assets 10,624   $ 10,518
Accrued and other current liabilities 14,549   14,468
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Selling, general and administrative 12 9  
Research and development 160 $ 128  
Other current assets 22   15
Accrued and other current liabilities $ 85   $ 113
v3.26.1
Collaborative Arrangements - Moderna, Inc. - Narrative (Details)
$ in Millions
Mar. 31, 2026
USD ($)
Moderna, Inc. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]  
Capitalization of shared costs $ 230
v3.26.1
Collaborative Arrangements - Moderna, Inc. (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Selling, general and administrative $ 2,700 $ 2,552  
Research and development 12,592 3,621  
Other current assets 10,624   $ 10,518
Accrued and other current liabilities 14,549   14,468
Moderna, Inc. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Selling, general and administrative 8 6  
Research and development 90 $ 86  
Other current assets 4   0
Accrued and other current liabilities $ 0   $ 13
v3.26.1
Collaborative Arrangements - Bristol Meyers Squibb Company - Narrative (Details) - Bristol Myers Squibb Company - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
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]    
Sales milestone payments $ 80  
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Revenue from collaborative arrangement $ 148 $ 119
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%  
v3.26.1
Restructuring - Narrative (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs $ 466  
Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Expected restructuring and related cost $ 3,000  
Estimate of cumulative pre tax costs that will be cash 60.00%  
Total pretax restructuring costs $ 318  
Cumulative costs since program inception 2,300  
Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Expected restructuring and related cost 4,000  
Total pretax restructuring costs 148 $ 105
Cumulative costs since program inception $ 1,800  
Estimate of cumulative pre tax costs that will be noncash 50.00%  
v3.26.1
Restructuring - Schedule of Charges Activities by Type of Cost (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs $ 466  
Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 318  
Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 148 $ 105
Accelerated Depreciation    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 108  
Accelerated Depreciation | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 12  
Accelerated Depreciation | Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 96 41
Separation Costs    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 123  
Separation Costs | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 123  
Separation Costs | Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 0 1
Other Exit Costs    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 235  
Other Exit Costs | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 183  
Other Exit Costs | Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 52 63
Cost of sales | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 144  
Cost of sales | Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 93 36
Cost of sales | Accelerated Depreciation | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 12  
Cost of sales | Accelerated Depreciation | Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 96 41
Cost of sales | Separation Costs | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 0  
Cost of sales | Separation Costs | Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 0 0
Cost of sales | Other Exit Costs | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 132  
Cost of sales | Other Exit Costs | Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs (3) (5)
Research and development | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 34  
Research and development | Accelerated Depreciation | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 0  
Research and development | Separation Costs | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 0  
Research and development | Other Exit Costs | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 34  
Restructuring costs | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 140  
Restructuring costs | Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 55 69
Restructuring costs | Accelerated Depreciation | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 0  
Restructuring costs | Accelerated Depreciation | Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 0 0
Restructuring costs | Separation Costs | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 123  
Restructuring costs | Separation Costs | Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 0 1
Restructuring costs | Other Exit Costs | Restructuring Program, 2025    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs 17  
Restructuring costs | Other Exit Costs | Restructuring Program, 2024    
Restructuring Cost and Reserve [Line Items]    
Total pretax restructuring costs $ 55 $ 68
v3.26.1
Restructuring - Schedule of Activities by Program (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Restructuring Reserve [Roll Forward]    
Expenses $ 466  
Restructuring Program, 2025    
Restructuring Reserve [Roll Forward]    
Restructuring reserve, beginning balance 790  
Expenses 318  
(Payments) receipts, net (322)  
Non-cash activity (138)  
Restructuring reserve, ending balance 648  
Restructuring Program, 2024    
Restructuring Reserve [Roll Forward]    
Restructuring reserve, beginning balance 506  
Expenses 148 $ 105
(Payments) receipts, net (123)  
Non-cash activity (83)  
Restructuring reserve, ending balance 448  
Accelerated Depreciation    
Restructuring Reserve [Roll Forward]    
Expenses 108  
Accelerated Depreciation | Restructuring Program, 2025    
Restructuring Reserve [Roll Forward]    
Restructuring reserve, beginning balance 0  
Expenses 12  
(Payments) receipts, net 0  
Non-cash activity (12)  
Restructuring reserve, ending balance 0  
Accelerated Depreciation | Restructuring Program, 2024    
Restructuring Reserve [Roll Forward]    
Restructuring reserve, beginning balance 0  
Expenses 96 41
(Payments) receipts, net 0  
Non-cash activity (96)  
Restructuring reserve, ending balance 0  
Separation Costs    
Restructuring Reserve [Roll Forward]    
Expenses 123  
Separation Costs | Restructuring Program, 2025    
Restructuring Reserve [Roll Forward]    
Restructuring reserve, beginning balance 502  
Expenses 123  
(Payments) receipts, net (156)  
Non-cash activity (9)  
Restructuring reserve, ending balance 460  
Separation Costs | Restructuring Program, 2024    
Restructuring Reserve [Roll Forward]    
Restructuring reserve, beginning balance 506  
Expenses 0 1
(Payments) receipts, net (70)  
Non-cash activity 12  
Restructuring reserve, ending balance 448  
Other Exit Costs    
Restructuring Reserve [Roll Forward]    
Expenses 235  
Other Exit Costs | Restructuring Program, 2025    
Restructuring Reserve [Roll Forward]    
Restructuring reserve, beginning balance 288  
Expenses 183  
(Payments) receipts, net (166)  
Non-cash activity (117)  
Restructuring reserve, ending balance 188  
Other Exit Costs | Restructuring Program, 2024    
Restructuring Reserve [Roll Forward]    
Restructuring reserve, beginning balance 0  
Expenses 52 $ 63
(Payments) receipts, net (53)  
Non-cash activity 1  
Restructuring reserve, ending balance $ 0  
v3.26.1
Financial Instruments - Narrative (Details)
$ in Millions
 3 Months Ended
Mar. 31, 2026
USD ($)
interest_rate_swap
Dec. 31, 2025
USD ($)
Mar. 31, 2025
USD ($)
Feb. 28, 2026
USD ($)
interest_rate_swap
Derivative [Line Items]        
Derivative, notional amount $ 42,106 $ 40,291    
Pretax net unrealized gains on derivatives maturing within the next 12 months estimated to be reclassified from AOCI to sales 69      
Equity investments without readily determinable fair values 881   $ 872  
Unrealized gains recognized on investments in equity securities without readily determinable fair value 35      
Unrealized losses recognized on investments in equity securities without readily determinable fair values     11  
Cumulative unrealized gains on investments 320      
Cumulative unrealized losses on investments 164      
Income from investments in equity securities, net (168)   (90)  
Fair value of loans payable and long-term debt, including current portion 44,700 45,600    
Debt, carrying amount 49,100 49,300    
Factored accounts receivable 1,600 1,600    
Cash collateral received from counterparties 89 1    
Accounts Receivable Factoring Collections        
Derivative [Line Items]        
Restricted cash 39 45    
Level 2        
Derivative [Line Items]        
Cash equivalents 4,400 13,800    
Equity Funds        
Derivative [Line Items]        
Publicly traded equity securities 229   249  
Income from investments in equity securities, net $ (3)   $ 23  
Interest rate swap contracts        
Derivative [Line Items]        
Number of Interest Rate Swaps Held | interest_rate_swap 10     2
Derivative, notional amount       $ 250
Derivatives Designated as Hedging Instruments        
Derivative [Line Items]        
Derivative, notional amount $ 16,317 14,712    
Derivatives Not Designated as Hedging Instruments        
Derivative [Line Items]        
Derivative, notional amount $ 25,789 $ 25,579    
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      
v3.26.1
Financial Instruments - Schedule of Effect of Net Investment Hedges (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Foreign exchange contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income $ (15) $ 27
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 4 3
Euro-denominated notes    
Derivative Instruments, Gain (Loss) [Line Items]    
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income (137) 130
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
v3.26.1
Financial Instruments - Schedule of Interest Rate Swaps Held (Details)
Mar. 31, 2026
USD ($)
interest_rate_swap
Feb. 28, 2026
USD ($)
interest_rate_swap
Dec. 31, 2025
USD ($)
Derivative [Line Items]      
U.S dollar notional amount $ 42,106,000,000   $ 40,291,000,000
4.50% note due 2033 | 4.50% note due 2033      
Derivative [Line Items]      
Stated interest rate 4.50%    
4.75% notes due 2035 | 4.75% notes due 2035      
Derivative [Line Items]      
Stated interest rate 4.75%    
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 10 2  
U.S dollar notional amount   $ 250,000,000  
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 | 4.75% notes due 2035      
Derivative [Line Items]      
Par Value of Debt $ 1,500,000,000    
Number of Interest Rate Swaps Held | interest_rate_swap 2    
U.S dollar notional amount $ 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 2    
U.S dollar notional amount $ 500,000,000    
v3.26.1
Financial Instruments - Schedule of Amounts Recorded on Balance Sheet Related to Fair Value Hedges (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
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 $ 2,539 $ 1,810
Cumulative Amount of Fair Value Hedging Adjustment Increase Included in the Carrying Amount $ 57 $ 70
v3.26.1
Financial Instruments - Schedule of 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
Mar. 31, 2026
Feb. 28, 2026
Dec. 31, 2025
Derivatives, Fair Value [Line Items]      
Fair value of derivative, asset $ 562   $ 323
Fair value of derivative, liability 229   324
U.S dollar notional amount 42,106   40,291
Derivatives Designated as Hedging Instruments      
Derivatives, Fair Value [Line Items]      
Fair value of derivative, asset 368   216
Fair value of derivative, liability 49   132
U.S dollar notional amount 16,317   14,712
Derivatives Not Designated as Hedging Instruments      
Derivatives, Fair Value [Line Items]      
Fair value of derivative, asset 194   107
Fair value of derivative, liability 180   192
U.S dollar notional amount 25,789   25,579
Interest rate swap contracts      
Derivatives, Fair Value [Line Items]      
Fair value of derivative, asset $ 58   $ 71
U.S dollar notional amount   $ 250  
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 $ 58   $ 71
Derivative asset, notional amount 2,500   1,750
Interest rate contracts      
Derivatives, Fair Value [Line Items]      
Fair value of derivative, asset $ 8   $ 0
Interest rate 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 $ 8   $ 0
Derivative asset, notional amount 500   0
Foreign exchange contracts      
Derivatives, Fair Value [Line Items]      
Fair value of derivative, asset 310   168
Fair value of derivative, liability $ 202   $ 293
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 $ 247   $ 113
Derivative asset, notional amount $ 7,751   $ 6,430
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 $ 55   $ 32
Derivative asset, notional amount $ 1,828   $ 1,793
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 $ 48   $ 131
Derivative liability, notional amount $ 3,705   $ 4,726
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 $ 1   $ 1
Derivative liability, notional amount $ 33   $ 13
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments      
Derivatives, Fair Value [Line Items]      
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other current assets   Other current assets
Fair value of derivative, asset $ 194   $ 107
Derivative asset, notional amount $ 13,870   $ 11,643
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 $ 180   $ 191
Derivative liability, notional amount $ 11,919   $ 13,579
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 $ 0   $ 1
Derivative liability, notional amount $ 0   $ 357
v3.26.1
Financial Instruments - Schedule of Information on Derivative Positions Subject to Master Netting Arrangements as if they were Presented on a Net Basis (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Gross amounts recognized in the consolidated balance sheet, asset $ 562 $ 323
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, asset (225) (245)
Cash collateral received, asset (89) (1)
Net amounts, asset 248 77
Gross amounts recognized in the consolidated balance sheet, liability 229 324
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, liability (225) (245)
Cash collateral received, liability 0 0
Net amounts, liability $ 4 $ 79
v3.26.1
Financial Instruments - Schedule of Location and Amount of Pretax (Gains) Losses of Derivatives (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Derivative Instruments, Gain (Loss) [Line Items]    
Sales $ 16,286 $ 15,529
Other (income) expense, net 138 (35)
Other comprehensive income (loss) 227 (20)
Interest rate swap contracts | Other (income) expense, net    
Derivative Instruments, Gain (Loss) [Line Items]    
Hedged items (14) 38
Derivatives designated as hedging instruments 13 (39)
Foreign exchange contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Amount of gain (loss) recognized in OCI on derivatives 168 (201)
(Decrease) increase in Sales as a result of AOCL reclassifications 98 (74)
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 (98) 74
Interest rate contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Amount of gain (loss) recognized in OCI on derivatives $ 7 $ 0
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Other (income) expense, net Other (income) expense, net
Amount of gain recognized in Other (income) expense, net on derivatives $ (1) $ 0
v3.26.1
Financial Instruments - Schedule of Income Statement Effects on Derivatives Not Designated as Hedging Instruments (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Currency Swap | Other (income) expense, net    
Derivative Instruments, Gain (Loss) [Line Items]    
Amount of Derivative Pretax Loss (Gain) Recognized in Income $ 36 $ (20)
Foreign Exchange Future | Sales    
Derivative Instruments, Gain (Loss) [Line Items]    
Amount of Derivative Pretax Loss (Gain) Recognized in Income $ 12 $ 16
v3.26.1
Financial Instruments - Schedule of Information on Available-for-sale Investments (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]      
Amortized Cost $ 476   $ 101
Debt securities, unrealized gains 0   0
Debt securities, unrealized losses 0   0
Debt securities, fair value 476   101
Publicly traded equity securities, fair value 1,571   1,392
Total debt and publicly traded equity securities, fair value 2,047   1,493
Unrealized net gains (losses) 126 $ (115)  
Commercial paper      
Debt Securities, Available-for-sale [Line Items]      
Amortized Cost 375   0
Debt securities, unrealized gains 0   0
Debt securities, unrealized losses 0   0
Debt securities, fair value 375   0
U.S. government and agency securities      
Debt Securities, Available-for-sale [Line Items]      
Amortized Cost 100   100
Debt securities, unrealized gains 0   0
Debt securities, unrealized losses 0   0
Debt securities, fair value 100   100
Foreign government bonds      
Debt Securities, Available-for-sale [Line Items]      
Amortized Cost 1   1
Debt securities, unrealized gains 0   0
Debt securities, unrealized losses 0   0
Debt securities, fair value $ 1   $ 1
v3.26.1
Financial Instruments - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Assets    
Commercial paper $ 476 $ 101
Publicly traded equity securities 1,571 1,392
Investments 1,480 956
Other Assets 567 537
Fair value of derivative, asset 562 323
Total assets 2,609 1,816
Liabilities    
Fair value of derivative, liability 229 324
Total liabilities 229 324
Foreign exchange contracts    
Assets    
Fair value of derivative, asset 310 168
Liabilities    
Fair value of derivative, liability 202 293
Purchased currency options    
Assets    
Fair value of derivative, asset 186 84
Liabilities    
Fair value of derivative, liability 27 31
Interest rate swap contracts    
Assets    
Fair value of derivative, asset 58 71
Interest rate contracts    
Assets    
Fair value of derivative, asset 8 0
Level 1    
Assets    
Investments 1,104 955
Other Assets 567 537
Fair value of derivative, asset 0 0
Total assets 1,671 1,492
Liabilities    
Total liabilities 0 0
Level 1 | Foreign exchange contracts    
Assets    
Fair value of derivative, asset 0 0
Liabilities    
Fair value of derivative, liability 0 0
Level 1 | Purchased currency options    
Assets    
Fair value of derivative, asset 0 0
Liabilities    
Fair value of derivative, liability 0 0
Level 1 | Interest rate swap contracts    
Assets    
Fair value of derivative, asset 0 0
Level 1 | Interest rate contracts    
Assets    
Fair value of derivative, asset 0 0
Level 2    
Assets    
Investments 376 1
Other Assets 0 0
Fair value of derivative, asset 562 323
Total assets 938 324
Liabilities    
Total liabilities 229 324
Level 2 | Foreign exchange contracts    
Assets    
Fair value of derivative, asset 310 168
Liabilities    
Fair value of derivative, liability 202 293
Level 2 | Purchased currency options    
Assets    
Fair value of derivative, asset 186 84
Liabilities    
Fair value of derivative, liability 27 31
Level 2 | Interest rate swap contracts    
Assets    
Fair value of derivative, asset 58 71
Level 2 | Interest rate contracts    
Assets    
Fair value of derivative, asset 8 0
Level 3    
Assets    
Investments 0 0
Other Assets 0 0
Fair value of derivative, asset 0 0
Total assets 0 0
Liabilities    
Total liabilities 0 0
Level 3 | Foreign exchange contracts    
Assets    
Fair value of derivative, asset 0 0
Liabilities    
Fair value of derivative, liability 0 0
Level 3 | Purchased currency options    
Assets    
Fair value of derivative, asset 0 0
Liabilities    
Fair value of derivative, liability 0 0
Level 3 | Interest rate swap contracts    
Assets    
Fair value of derivative, asset 0 0
Level 3 | Interest rate contracts    
Assets    
Fair value of derivative, asset 0 0
Commercial paper    
Assets    
Commercial paper 375 0
Commercial paper | Level 1    
Assets    
Commercial paper 0 0
Commercial paper | Level 2    
Assets    
Commercial paper 375 0
Commercial paper | Level 3    
Assets    
Commercial paper 0 0
Foreign government bonds    
Assets    
Commercial paper 1 1
Foreign government bonds 1 1
Foreign government bonds | Level 1    
Assets    
Foreign government bonds 0 0
Foreign government bonds | Level 2    
Assets    
Foreign government bonds 1 1
Foreign government bonds | Level 3    
Assets    
Foreign government bonds 0 0
Publicly traded equity securities    
Assets    
Publicly traded equity securities 1,104 955
Publicly traded equity securities 467 437
Publicly traded equity securities | Level 1    
Assets    
Publicly traded equity securities 1,104 955
Publicly traded equity securities 467 437
Publicly traded equity securities | Level 1 | July 2026 Expiration    
Liabilities    
Securities subject to contractual sale restrictions 17  
Publicly traded equity securities | Level 1 | August 2026 Expiration    
Liabilities    
Securities subject to contractual sale restrictions 18  
Publicly traded equity securities | Level 2    
Assets    
Publicly traded equity securities 0 0
Publicly traded equity securities 0 0
Publicly traded equity securities | Level 3    
Assets    
Publicly traded equity securities 0 0
Publicly traded equity securities 0 0
U.S. government and agency securities    
Assets    
Commercial paper 100 100
U.S. government and agency securities 100 100
U.S. government and agency securities | Level 1    
Assets    
U.S. government and agency securities 100 100
U.S. government and agency securities | Level 2    
Assets    
U.S. government and agency securities 0 0
U.S. government and agency securities | Level 3    
Assets    
U.S. government and agency securities $ 0 $ 0
v3.26.1
Inventories - Schedule of Inventories (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Inventory Disclosure [Abstract]    
Finished goods $ 2,211 $ 2,275
Raw materials and work in process 11,136 10,645
Supplies 334 331
Total 13,681 13,251
Decrease to LIFO cost (1,007) (912)
Total current and noncurrent inventories 12,674 12,339
Recognized as:    
Inventories 6,479 6,658
Other Assets $ 6,195 $ 5,681
v3.26.1
Inventories - Narrative (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Inventory [Line Items]    
Inventories classified in other assets $ 6,195 $ 5,681
Inventories Not Expected to be Sold Within One Year    
Inventory [Line Items]    
Inventories classified in other assets 5,800 5,500
Inventories Produced in Preparation for Product Launches    
Inventory [Line Items]    
Inventories classified in other assets $ 360 $ 211
v3.26.1
Loans Payable (Details) - USD ($)
$ in Billions
 1 Months Ended
Apr. 30, 2026
Mar. 31, 2026
Terns Pharmaceuticals, Inc.    
Short-Term Debt [Line Items]    
Consideration transferred, asset acquisition   $ 6.7
Secured Debt | Delayed Draw Term Loan Credit Agreement | Line of Credit | Subsequent Event    
Short-Term Debt [Line Items]    
Debt instrument, term 364 days  
Line of credit facility, maximum borrowing capacity $ 6.0  
Secured Debt | Delayed Draw Term Loan Credit Agreement | Variable Rate Component One | Line of Credit | Subsequent Event    
Short-Term Debt [Line Items]    
Debt instrument, term 180 days  
Debt instrument, basis spread on variable rate 0.50%  
Secured Debt | Delayed Draw Term Loan Credit Agreement | Variable Rate Component Two | Line of Credit | Subsequent Event    
Short-Term Debt [Line Items]    
Debt instrument, basis spread on variable rate 0.75%  
v3.26.1
Contingencies (Details)
$ in Millions
 1 Months Ended 2 Months Ended 3 Months Ended 5 Months Ended
Apr. 24, 2025
patent
Mar. 13, 2025
Jun. 30, 2023
May 31, 2023
patent
Mar. 31, 2026
USD ($)
case
company
Oct. 31, 2025
patent
Oct. 31, 2024
patent
Dec. 31, 2025
USD ($)
Jun. 02, 2025
patent
Mar. 11, 2025
case
Legal Defense Costs                    
Loss Contingencies [Line Items]                    
Legal defense costs reserve | $         $ 270     $ 245    
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         735          
Gardasil/Gardasil 9 | U.S. | Pending Litigation                    
Loss Contingencies [Line Items]                    
Loss contingency, pending claims | case         135          
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          
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, number of patents allegedly infringed       9     9      
Number of additional patents unpatentable           9        
Subcutaneous Pembrolizumab | Pending Litigation | Patents                    
Loss Contingencies [Line Items]                    
Loss contingency, pending claims                 1  
Loss contingency, number of patents allegedly infringed 15                  
Subcutaneous Pembrolizumab | Pending Litigation | Patents - PGR Petition                    
Loss Contingencies [Line Items]                    
Loss contingency, pending claims                 13  
Subcutaneous Pembrolizumab | Pending Litigation | PGR Petition Process, Ineligible to be Challenged                    
Loss Contingencies [Line Items]                    
Loss contingency, pending claims 3                  
v3.26.1
Equity (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Common stock, beginning balance (in shares) 3,577,103,522  
Equity, beginning balance $ 52,662 $ 46,372
Treasury stock, beginning balance (in shares) 1,102,476,756  
Net income (loss) attributable to Merck & Co., Inc. $ (4,240) 5,079
Other comprehensive loss, net of taxes 227 (20)
Cash dividends declared on common stock (2,114) (2,051)
Treasury stock shares purchased (925) (1,164)
Share-based compensation plans and other 324 178
Net income (loss) attributable to noncontrolling interests $ (3) 6
Common stock, ending balance (in shares) 3,577,103,522  
Equity, ending balance $ 45,931 $ 48,400
Treasury stock, ending balance (in shares) 1,107,410,143  
Cash dividends declared on common stock (in dollars per share) $ 0.85 $ 0.81
  Common Stock    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Common stock, beginning balance (in shares) 3,577,000,000 3,577,000,000
Equity, beginning balance $ 1,788 $ 1,788
Common stock, ending balance (in shares) 3,577,000,000 3,577,000,000
Equity, ending balance $ 1,788 $ 1,788
Other Paid-In Capital    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Equity, beginning balance 45,029 44,704
Share-based compensation plans and other 147 112
Equity, ending balance 45,176 44,816
Retained Earnings    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Equity, beginning balance 73,075 63,069
Net income (loss) attributable to Merck & Co., Inc. (4,240) 5,079
Cash dividends declared on common stock (2,114) (2,051)
Equity, ending balance 66,721 66,097
Accumulated Other Comprehensive Loss    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Equity, beginning balance (4,287) (4,945)
Other comprehensive loss, net of taxes 227 (20)
Equity, ending balance (4,060) (4,965)
 Treasury Stock    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Equity, beginning balance $ (62,999) $ (58,303)
Treasury stock, beginning balance (in shares) 1,102,000,000 1,049,000,000
Treasury stock shares purchased (in shares) 8,000,000 13,000,000
Treasury stock shares purchased $ (925) $ (1,164)
Share-based compensation plans and other $ 177 $ 66
Share-based compensation plans and other (in shares) (3,000,000) (1,000,000)
Equity, ending balance $ (63,747) $ (59,401)
Treasury stock, ending balance (in shares) 1,107,000,000 1,061,000,000
Non- controlling Interests    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Equity, beginning balance $ 56 $ 59
Net income (loss) attributable to noncontrolling interests (3) 6
Equity, ending balance $ 53 $ 65
v3.26.1
Pension and Other Postretirement Benefit Plans - Schedule of Net Benefit Costs (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Other Postretirement Benefit Plans    
Defined Benefit Plan Disclosure [Line Items]    
Service cost $ 11 $ 10
Interest cost 16 16
Expected return on plan assets (14) (14)
Amortization of unrecognized prior service credit (9) (10)
Net loss (gain) amortization (8) (10)
Termination benefits 1 0
Net periodic benefit cost (3) (8)
U.S. | Pension Plans    
Defined Benefit Plan Disclosure [Line Items]    
Service cost 98 89
Interest cost 145 141
Expected return on plan assets (207) (210)
Amortization of unrecognized prior service credit 0 0
Net loss (gain) amortization 27 13
Termination benefits 3 0
Net periodic benefit cost 66 33
International | Pension Plans    
Defined Benefit Plan Disclosure [Line Items]    
Service cost 48 54
Interest cost 81 71
Expected return on plan assets (161) (143)
Amortization of unrecognized prior service credit (4) (4)
Net loss (gain) amortization (1) 3
Termination benefits 15 0
Net periodic benefit cost $ (22) $ (19)
v3.26.1
Other (Income) Expense, Net - Schedule of Other (Income) Expense, Net (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Other Income and Expenses [Abstract]    
Interest income $ (35) $ (109)
Interest expense 479 313
Exchange losses 38 90
Income from investments in equity securities, net (168) (90)
Net periodic defined benefit plan (credit) cost other than service cost (134) (148)
Other, net (42) (91)
Other (income) expense, net $ 138 $ (35)
v3.26.1
Other (Income) Expense, Net - Narrative (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Other Income and Expenses [Abstract]    
Interest paid $ 342 $ 233
v3.26.1
Income Taxes (Details) - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended
Apr. 30, 2025
Mar. 31, 2026
Mar. 31, 2025
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]      
Income tax provision   $ 709 $ 818
Pretax loss   $ (3,534) $ 5,903
Effective income tax rate   (20.10%) 13.90%
Income tax rate, unfavorable discrete impact   33.10%  
Internal Revenue Service (IRS)      
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]      
Income tax examination, estimate of possible loss $ 1,300    
Internal Revenue Service (IRS) | Penalties      
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]      
Income tax examination, estimate of possible loss $ 260    
v3.26.1
(Loss) Earnings Per Share - Calculations of (Loss) Earnings Per Share (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Earnings Per Share [Abstract]    
Net (Loss) Income Attributable to Merck & Co., basic $ (4,240) $ 5,079
Net (Loss) Income Attributable to Merck & Co., diluted $ (4,240) $ 5,079
Average common shares outstanding (in shares) 2,472 2,523
Common shares issuable (in shares) 0 8
Average common shares outstanding assuming dilution (in shares) 2,472 2,531
Basic (Loss) Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ (1.72) $ 2.01
(Loss) Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ (1.72) $ 2.01
v3.26.1
(Loss) Earnings Per Share - Narrative (Details) - shares
shares in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Earnings Per Share [Abstract]    
Antidilutive shares (in shares) 0 10
v3.26.1
Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Accumulated Other Comprehensive Income (Loss) [Roll Forward]    
Equity, beginning balance $ 52,662 $ 46,372
Other comprehensive income (loss), net of taxes 227 (20)
Equity, ending balance 45,931 48,400
Accumulated Other Comprehensive Loss    
Accumulated Other Comprehensive Income (Loss) [Roll Forward]    
Equity, beginning balance (4,287) (4,945)
Other comprehensive income (loss) before reclassification adjustments, pretax 184 (2)
Tax (43) 57
Other comprehensive income (loss) before reclassification adjustments, net of taxes 141 55
Reclassification adjustments, pretax 110 (83)
Tax (24) 8
Reclassification adjustments, net of taxes 86 (75)
Other comprehensive income (loss), net of taxes 227 (20)
Equity, ending balance (4,060) (4,965)
Derivatives    
Accumulated Other Comprehensive Income (Loss) [Roll Forward]    
Equity, beginning balance (105) 242
Other comprehensive income (loss) before reclassification adjustments, pretax 168 (201)
Tax (35) 42
Other comprehensive income (loss) before reclassification adjustments, net of taxes 133 (159)
Reclassification adjustments, pretax 105 (73)
Tax (22) 15
Reclassification adjustments, net of taxes 83 (58)
Other comprehensive income (loss), net of taxes 216 (217)
Equity, ending balance 111 25
Employee Benefit Plans    
Accumulated Other Comprehensive Income (Loss) [Roll Forward]    
Equity, beginning balance (1,499) (2,327)
Other comprehensive income (loss) before reclassification adjustments, pretax 1 (1)
Tax 1 0
Other comprehensive income (loss) before reclassification adjustments, net of taxes 2 (1)
Reclassification adjustments, pretax 5 (10)
Tax (2) (7)
Reclassification adjustments, net of taxes 3 (17)
Other comprehensive income (loss), net of taxes 5 (18)
Equity, ending balance (1,494) (2,345)
Foreign Currency Translation Adjustment    
Accumulated Other Comprehensive Income (Loss) [Roll Forward]    
Equity, beginning balance (2,683) (2,860)
Other comprehensive income (loss) before reclassification adjustments, pretax 15 200
Tax (9) 15
Other comprehensive income (loss) before reclassification adjustments, net of taxes 6 215
Reclassification adjustments, pretax 0 0
Tax 0 0
Reclassification adjustments, net of taxes 0 0
Other comprehensive income (loss), net of taxes 6 215
Equity, ending balance $ (2,677) $ (2,645)
v3.26.1
Segment Reporting - Narrative (Details)
$ in Billions
 3 Months Ended
Mar. 31, 2026
USD ($)
segment
Mar. 31, 2025
USD ($)
Segment Reporting [Abstract]    
Number of operating segments 2  
Number of reportable segments 2  
Sales discounts | $ $ 2.5 $ 2.1
v3.26.1
Segment Reporting - Schedule of Sales from Products (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Segment Reporting Information [Line Items]    
Sales $ 16,286 $ 15,529
Increase in hedge revenue (110) 58
Revenue related to the sale of the marketing rights 132 95
U.S.    
Segment Reporting Information [Line Items]    
Sales 9,164 8,522
Non-US    
Segment Reporting Information [Line Items]    
Sales 7,122 7,007
Operating Segments    
Segment Reporting Information [Line Items]    
Sales 16,140 15,226
Operating Segments | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 14,349 13,638
Operating Segments | Animal Health    
Segment Reporting Information [Line Items]    
Sales 1,791 1,588
Operating Segments | U.S.    
Segment Reporting Information [Line Items]    
Sales 9,031 8,429
Operating Segments | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 8,512 7,927
Operating Segments | U.S. | Animal Health    
Segment Reporting Information [Line Items]    
Sales 519 502
Operating Segments | Non-US    
Segment Reporting Information [Line Items]    
Sales 7,109 6,797
Operating Segments | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 5,837 5,711
Operating Segments | Non-US | Animal Health    
Segment Reporting Information [Line Items]    
Sales 1,272 1,086
Operating Segments | Keytruda | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 7,906 7,205
Operating Segments | Keytruda | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 4,599 4,308
Operating Segments | Keytruda | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 3,307 2,897
Operating Segments | Keytruda Qlex | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 128 0
Operating Segments | Keytruda Qlex | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 106 0
Operating Segments | Keytruda Qlex | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 21 0
Operating Segments | Alliance revenue - Lynparza | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 341 312
Operating Segments | Alliance revenue - Lynparza | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 149 145
Operating Segments | Alliance revenue - Lynparza | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 192 168
Operating Segments | Alliance revenue - Lenvima | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 256 258
Operating Segments | Alliance revenue - Lenvima | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 176 186
Operating Segments | Alliance revenue - Lenvima | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 80 72
Operating Segments | Welireg | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 199 137
Operating Segments | Welireg | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 152 123
Operating Segments | Welireg | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 47 15
Operating Segments | Alliance Revenue - Reblozyl | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 148 119
Operating Segments | Alliance Revenue - Reblozyl | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 128 101
Operating Segments | Alliance Revenue - Reblozyl | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 20 18
Operating Segments | Gardasil/Gardasil 9 | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 1,069 1,327
Operating Segments | Gardasil/Gardasil 9 | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 485 536
Operating Segments | Gardasil/Gardasil 9 | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 585 790
Operating Segments | ProQuad/M-M-R II/Varivax | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 538 539
Operating Segments | ProQuad/M-M-R II/Varivax | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 409 423
Operating Segments | ProQuad/M-M-R II/Varivax | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 129 116
Operating Segments | RotaTeq | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 206 228
Operating Segments | RotaTeq | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 165 164
Operating Segments | RotaTeq | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 42 64
Operating Segments | Vaxneuvance | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 202 230
Operating Segments | Vaxneuvance | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 123 139
Operating Segments | Vaxneuvance | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 78 92
Operating Segments | Capvaxive | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 142 107
Operating Segments | Capvaxive | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 118 106
Operating Segments | Capvaxive | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 23 1
Operating Segments | Winrevair | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 525 280
Operating Segments | Winrevair | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 477 268
Operating Segments | Winrevair | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 48 12
Operating Segments | Ohtuvayre | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 131 0
Operating Segments | Ohtuvayre | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 131 0
Operating Segments | Ohtuvayre | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 0 0
Operating Segments | Alliance revenue - Adempas/Verquvo | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 109 106
Operating Segments | Alliance revenue - Adempas/Verquvo | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 109 97
Operating Segments | Alliance revenue - Adempas/Verquvo | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 0 9
Operating Segments | Adempas | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 78 68
Operating Segments | Adempas | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 0 0
Operating Segments | Adempas | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 78 68
Operating Segments | Bridion | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 472 441
Operating Segments | Bridion | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 427 378
Operating Segments | Bridion | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 45 63
Operating Segments | Prevymis | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 272 208
Operating Segments | Prevymis | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 135 102
Operating Segments | Prevymis | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 138 106
Operating Segments | Zerbaxa | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 82 70
Operating Segments | Zerbaxa | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 52 42
Operating Segments | Zerbaxa | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 30 28
Operating Segments | Delstrigo | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 75 67
Operating Segments | Delstrigo | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 10 15
Operating Segments | Delstrigo | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 65 52
Operating Segments | Isentress/Isentress HD | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 59 90
Operating Segments | Isentress/Isentress HD | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 35 51
Operating Segments | Isentress/Isentress HD | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 24 39
Operating Segments | Dificid | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 34 83
Operating Segments | Dificid | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 24 72
Operating Segments | Dificid | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 10 11
Operating Segments | Lagevrio | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 28 102
Operating Segments | Lagevrio | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 16 35
Operating Segments | Lagevrio | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 12 67
Operating Segments | Januvia | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 367 549
Operating Segments | Januvia | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 252 344
Operating Segments | Januvia | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 116 204
Operating Segments | Janumet | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 207 247
Operating Segments | Janumet | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 68 65
Operating Segments | Janumet | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 139 182
Operating Segments | Other pharmaceutical | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 775 865
Operating Segments | Other pharmaceutical | U.S. | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 166 227
Operating Segments | Other pharmaceutical | Non-US | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 608 637
Operating Segments | Livestock | Animal Health    
Segment Reporting Information [Line Items]    
Sales 1,064 924
Operating Segments | Livestock | U.S. | Animal Health    
Segment Reporting Information [Line Items]    
Sales 211 194
Operating Segments | Livestock | Non-US | Animal Health    
Segment Reporting Information [Line Items]    
Sales 853 730
Operating Segments | Companion Animal | Animal Health    
Segment Reporting Information [Line Items]    
Sales 727 664
Operating Segments | Companion Animal | U.S. | Animal Health    
Segment Reporting Information [Line Items]    
Sales 308 308
Operating Segments | Companion Animal | Non-US | Animal Health    
Segment Reporting Information [Line Items]    
Sales 419 356
Operating Segments | Alliance revenue - Koselugo | Pharmaceutical    
Segment Reporting Information [Line Items]    
Sales 161 44
Corporate, Non-Segment    
Segment Reporting Information [Line Items]    
Sales 146 303
Corporate, Non-Segment | U.S.    
Segment Reporting Information [Line Items]    
Sales 133 93
Corporate, Non-Segment | Non-US    
Segment Reporting Information [Line Items]    
Sales $ 13 $ 210
v3.26.1
Segment Reporting - Schedule of Consolidated Sales by Geographic Area (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Revenue from External Customer [Line Items]    
Sales $ 16,286 $ 15,529
United States    
Revenue from External Customer [Line Items]    
Sales 9,164 8,522
Europe, Middle East and Africa    
Revenue from External Customer [Line Items]    
Sales 3,886 3,454
Latin America    
Revenue from External Customer [Line Items]    
Sales 874 792
Asia Pacific (other than China and Japan)    
Revenue from External Customer [Line Items]    
Sales 738 689
Japan    
Revenue from External Customer [Line Items]    
Sales 555 669
China    
Revenue from External Customer [Line Items]    
Sales 390 702
Other    
Revenue from External Customer [Line Items]    
Sales $ 679 $ 701
v3.26.1
Segment Reporting - Schedule of Reconciliation of Segment Profits to Income before Taxes (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Segment Reporting Information [Line Items]    
Sales $ 16,286 $ 15,529
Less segment costs:    
Cost of sales 4,195 3,419
Selling, general and administrative 2,700 2,552
Research and development (12,592) (3,621)
Other segment items (138) 35
Pretax loss (3,534) 5,903
Other profits (3,534) 5,903
Unallocated:    
Interest income 35 109
Interest expense (479) (313)
Amortization (931) (597)
Depreciation (581) (502)
Research and development (12,592) (3,621)
Restructuring costs (195) (69)
Total segment profits    
Segment Reporting Information [Line Items]    
Sales 16,140 15,226
Less segment costs:    
Pretax loss 12,241 11,346
Other profits 12,241 11,346
Unallocated:    
Depreciation (90) (61)
Total segment profits | Pharma- ceutical    
Segment Reporting Information [Line Items]    
Sales 14,349 13,638
Less segment costs:    
Cost of sales 1,553 1,573
Selling, general and administrative 1,332 1,402
Research and development 0 0
Other segment items (55) (49)
Pretax loss 11,519 10,712
Other profits 11,519 10,712
Unallocated:    
Depreciation (1) (1)
Research and development 0 0
Total segment profits | Animal Health    
Segment Reporting Information [Line Items]    
Sales 1,791 1,588
Less segment costs:    
Cost of sales 675 600
Selling, general and administrative 282 260
Research and development (112) (95)
Other segment items 0 (1)
Pretax loss 722 634
Other profits 722 634
Unallocated:    
Depreciation (89) (60)
Research and development (112) (95)
Other profits    
Segment Reporting Information [Line Items]    
Sales 146 303
Less segment costs:    
Research and development (12,404) (3,477)
Pretax loss 106 202
Other profits 106 202
Unallocated:    
Interest income 35 109
Interest expense (479) (313)
Amortization (931) (597)
Depreciation (491) (441)
Research and development (12,404) (3,477)
Restructuring costs (195) (69)
Other unallocated, net $ (1,416) $ (857)
v3.26.1
Segment Reporting - Schedule of Equity Income from Affiliates and Depreciation Included in Segment Profits (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Segment Reporting Information [Line Items]    
Depreciation $ 581 $ 502
Operating Segments    
Segment Reporting Information [Line Items]    
Equity income from affiliates 62 58
Depreciation 90 61
Operating Segments | Pharma- ceutical    
Segment Reporting Information [Line Items]    
Equity income from affiliates 62 58
Depreciation 1 1
Operating Segments | Animal Health    
Segment Reporting Information [Line Items]    
Equity income from affiliates 0 0
Depreciation $ 89 $ 60
v3.26.1
Segment Reporting - Schedule of Property, Plant and Equipment, Net by Geographic Area (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net $ 25,433 $ 25,316
United States    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 15,097 15,021
Europe, Middle East and Africa    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 8,966 8,856
Asia Pacific (other than China and Japan)    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 842 898
China    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 213 218
Japan    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 136 144
Latin America    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 128 128
Other    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net $ 51 $ 51