MERCK & CO., INC., 10-Q filed on 11/5/2025
Quarterly Report
v3.25.3
Cover Page - shares
9 Months Ended
Sep. 30, 2025
Oct. 31, 2025
Entity Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 30, 2025  
Document Transition Report false  
Entity File Number 1-6571  
Entity Registrant Name Merck & Co., Inc.  
Entity Incorporation, State or Country Code NJ  
Entity Tax Identification Number 22-1918501  
Entity Address, Address Line One 126 East Lincoln Avenue  
Entity Address, City or Town Rahway  
Entity Address, State or Province NJ  
Entity Address, Postal Zip Code 07065  
City Area Code (908)  
Local Phone Number 740-4000  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   2,482,022,536
Amendment Flag false  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q3  
Entity Central Index Key 0000310158  
Current Fiscal Year End Date --12-31  
Common Stock ($0.50 par value)    
Entity Information [Line Items]    
Title of 12(b) Security Common Stock ($0.50 par value)  
Trading Symbol MRK  
Security Exchange Name NYSE  
1.875% Notes due 2026    
Entity Information [Line Items]    
Title of 12(b) Security 1.875% Notes due 2026  
Trading Symbol MRK/26  
Security Exchange Name NYSE  
3.250% Notes due 2032    
Entity Information [Line Items]    
Title of 12(b) Security 3.250% Notes due 2032  
Trading Symbol MRK/32  
Security Exchange Name NYSE  
2.500% Notes due 2034    
Entity Information [Line Items]    
Title of 12(b) Security 2.500% Notes due 2034  
Trading Symbol MRK/34  
Security Exchange Name NYSE  
1.375% Notes due 2036    
Entity Information [Line Items]    
Title of 12(b) Security 1.375% Notes due 2036  
Trading Symbol MRK 36A  
Security Exchange Name NYSE  
3.500% Notes due 2037    
Entity Information [Line Items]    
Title of 12(b) Security 3.500% Notes due 2037  
Trading Symbol MRK/37  
Security Exchange Name NYSE  
3.700% Notes due 2044    
Entity Information [Line Items]    
Title of 12(b) Security 3.700% Notes due 2044  
Trading Symbol MRK/44  
Security Exchange Name NYSE  
3.750% Notes due 2054    
Entity Information [Line Items]    
Title of 12(b) Security 3.750% Notes due 2054  
Trading Symbol MRK/54  
Security Exchange Name NYSE  
v3.25.3
CONDENSED CONSOLIDATED STATEMENT OF INCOME - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Income Statement [Abstract]        
Sales $ 17,276 $ 16,657 $ 48,611 $ 48,544
Costs, Expenses and Other        
Cost of sales 3,855 4,080 10,831 11,365
Selling, general and administrative 2,633 2,731 7,835 7,952
Research and development 4,234 5,862 11,903 13,354
Restructuring costs 47 56 676 258
Other (income) expense, net (238) (162) (281) (151)
Total Costs, Expenses and Other 10,531 12,567 30,964 32,778
Income Before Taxes 6,745 4,090 17,647 15,766
Taxes on Income 958 929 2,346 2,377
Net Income 5,787 3,161 15,301 13,389
Less: Net Income Attributable to Noncontrolling Interests 2 4 10 15
Net Income Attributable to Merck & Co., Inc. $ 5,785 $ 3,157 $ 15,291 $ 13,374
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 2.32 $ 1.25 $ 6.09 $ 5.28
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 2.32 $ 1.24 $ 6.08 $ 5.26
v3.25.3
CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Statement of Comprehensive Income [Abstract]        
Net Income Attributable to Merck & Co., Inc. $ 5,785 $ 3,157 $ 15,291 $ 13,374
Other Comprehensive Income (Loss) Net of Taxes:        
Net unrealized gain (loss) on derivatives, net of reclassifications 170 (296) (457) (99)
Benefit plan net gain (loss) and prior service credit (cost), net of amortization 74 (13) 48 (28)
Cumulative translation adjustment (25) 299 152 (83)
Other comprehensive income (loss), net of taxes 219 (10) (257) (210)
Comprehensive Income Attributable to Merck & Co., Inc. $ 6,004 $ 3,147 $ 15,034 $ 13,164
v3.25.3
CONDENSED CONSOLIDATED BALANCE SHEET - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Current Assets    
Cash and cash equivalents $ 18,169 $ 13,242
Short-term investments 45 447
Accounts receivable (net of allowance for doubtful accounts of $93 in 2025 and $89 in 2024) 12,120 10,278
Inventories (excludes inventories of $5,412 in 2025 and $4,193 in 2024 classified in Other assets - see Note 6) 6,444 6,109
Other current assets 10,779 8,706
Total current assets 47,557 38,782
Investments 1,117 463
Property, Plant and Equipment, at cost, net of accumulated depreciation of $20,605 in 2025 and $19,155 in 2024 25,639 23,779
Goodwill 21,587 21,668
Other Intangibles, Net 15,313 16,370
Other Assets 18,333 16,044
Total Assets 129,546 117,106
Current Liabilities    
Loans payable and current portion of long-term debt 1,405 2,649
Trade accounts payable 4,147 4,079
Accrued and other current liabilities 16,186 15,694
Income taxes payable 4,848 3,914
Dividends payable 2,042 2,084
Total current liabilities 28,628 28,420
Long-Term Debt 39,969 34,462
Deferred Income Taxes 1,381 1,387
Other Noncurrent Liabilities 7,661 6,465
Merck & Co., Inc. Stockholders’ Equity    
Common stock, $0.50 par value Authorized - 6,500,000,000 shares Issued - 3,577,103,522 shares in 2025 and 2024 1,788 1,788
Other paid-in capital 44,832 44,704
Retained earnings 72,231 63,069
Accumulated other comprehensive loss (5,202) (4,945)
Stockholders' equity before deduction for treasury stock 113,649 104,616
Less treasury stock, at cost: 1,089,754,712 shares in 2025 and 1,049,466,187 shares in 2024 61,799 58,303
Total Merck & Co., Inc. stockholders’ equity 51,850 46,313
Noncontrolling Interests 57 59
Total equity 51,907 46,372
Liabilities and Equity $ 129,546 $ 117,106
v3.25.3
CONDENSED CONSOLIDATED BALANCE SHEET (Parenthetical) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Statement of Financial Position [Abstract]    
Allowance for doubtful accounts $ 93 $ 89
Inventories classified in other assets 5,412 4,193
Accumulated depreciation $ 20,605 $ 19,155
Common stock, par value (in dollars per share) $ 0.50 $ 0.50
Common stock, authorized (in shares) 6,500,000,000 6,500,000,000
Common stock, issued (in shares) 3,577,103,522 3,577,103,522
Treasury stock (in shares) 1,089,754,712 1,049,466,187
v3.25.3
CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Cash Flows from Operating Activities    
Net income $ 15,301 $ 13,389
Adjustments to reconcile net income to net cash provided by operating activities:    
Amortization 1,820 1,720
Depreciation 1,552 1,582
Income from investments in equity securities, net (563) (169)
Charges for research and development asset acquisitions 0 2,756
Deferred income taxes (846) (633)
Share-based compensation 615 574
Other 393 611
Net changes in assets and liabilities (4,657) (1,812)
Net Cash Provided by Operating Activities 13,615 18,018
Cash Flows from Investing Activities    
Capital expenditures (3,079) (2,435)
Purchases of securities and other investments (1,207) (64)
Proceeds from sales of securities and other investments 1,632 370
Acquisition of Eyebiotech Limited, net of cash acquired 0 (1,344)
Acquisition of Elanco Animal Health Incorporated aqua business 0 (1,301)
Acquisition of Harpoon Therapeutics, Inc., net of cash acquired 0 (746)
Acquisition of MK-1045 (formerly CN201) from Curon Pharmaceutical 0 (700)
Other 114 (70)
Net Cash Used in Investing Activities (2,540) (6,290)
Cash Flows from Financing Activities    
Net change in short-term borrowings 63 0
Proceeds from issuance of debt 5,962 3,599
Payments on debt (2,501) (751)
Dividends paid to stockholders (6,158) (5,889)
Purchases of treasury stock (3,832) (817)
Proceeds from exercise of stock options 45 165
Other (252) (330)
Net Cash Used in Financing Activities (6,673) (4,023)
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash 540 74
Net Increase in Cash, Cash Equivalents and Restricted Cash 4,942 7,779
Cash, Cash Equivalents and Restricted Cash at Beginning of Year (includes restricted cash of $76 and $68 at January 1, 2025 and 2024, respectively, included in Other current assets) 13,318 6,909
Cash, Cash Equivalents and Restricted Cash at End of Period (includes restricted cash of $91 and $95 at September 30, 2025 and 2024, respectively, included in Other current assets) $ 18,260 $ 14,688
v3.25.3
CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Parenthetical) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Sep. 30, 2024
Dec. 31, 2023
Statement of Cash Flows [Abstract]        
Restricted cash $ 91 $ 76 $ 95 $ 68
v3.25.3
Basis of Presentation
9 Months Ended
Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Basis of Presentation Basis of Presentation
The accompanying unaudited condensed consolidated financial statements of Merck & Co., Inc. (Merck or the Company) have been prepared pursuant to the rules and regulations for reporting on Form 10-Q. Accordingly, certain information and disclosures required by accounting principles generally accepted in the United States (U.S.) for complete consolidated financial statements are not included herein. These interim statements should be read in conjunction with the audited financial statements and notes thereto included in Merck’s Form 10-K filed on February 25, 2025.
The results of operations of any interim period are not necessarily indicative of the results of operations for the full year. In the Company’s opinion, all adjustments necessary for a fair statement of these interim statements have been included and are of a normal and recurring nature. Certain reclassifications have been made to prior year amounts to conform to the current year presentation.
Recently Issued Accounting Standards Not Yet Adopted
In December 2023, the Financial Accounting Standards Board (FASB) issued guidance intended to improve the transparency of income tax disclosures by requiring consistent categories and disaggregation of information in the effective income tax rate reconciliation and income taxes paid disclosures by jurisdiction. The guidance also includes other amendments to improve the effectiveness of income tax disclosures by removing certain previously required disclosures. The guidance is effective for 2025 annual reporting and will result in incremental disclosures within the footnotes to the Company’s financial statements.
In November 2024, the FASB issued guidance intended to improve financial reporting by requiring entities to disclose additional information about specific expense categories at interim and annual reporting periods. The guidance is effective for 2027 annual reporting and 2028 interim reporting. Early adoption is permitted. The guidance, which can be applied on a prospective or retrospective basis, will result in incremental disclosures within the footnotes to the Company’s financial statements.
In September 2025, the FASB issued guidance intended to clarify and modernize the accounting for costs related to internal-use software. The guidance removes all references to software development project stages and clarifies the criteria entities should apply to begin capitalizing costs. The guidance is effective for 2028 annual and interim reporting and can be applied on a prospective, retrospective, or modified retrospective basis. Early adoption is permitted. The Company is currently evaluating the impact of adoption on its consolidated financial statements.
v3.25.3
Acquisitions, Research Collaborations and Licensing Agreements
9 Months Ended
Sep. 30, 2025
Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract]  
Acquisitions, Research Collaborations and Licensing Agreements Acquisitions, Research Collaborations and Licensing Agreements
The Company continues to pursue acquisitions and the establishment of external alliances such as research collaborations and licensing agreements to complement its internal research capabilities. These arrangements often include upfront payments; expense reimbursements or payments to the third party; milestone, royalty or profit share arrangements contingent upon the occurrence of certain future events linked to the success of the asset in development; and can also include option and continuation payments. The Company also reviews its marketed products and pipeline to examine candidates which may provide more value through out-licensing and, as part of its portfolio assessment process, may also divest certain assets. Pro forma financial information for acquired businesses is not presented if the historical financial results of the acquired entity are not significant when compared with the Company’s financial results.
2025 Transactions
In November 2025, Merck reached an agreement with Dr. Falk Pharma GmbH (Falk) to discontinue an existing contract concerning co-development and co-commercialization rights in certain territories for MK-8690 (formerly PRA-052), and for Merck to assume full responsibility for the development program going forward. MK-8690 is an investigational anti-CD30 ligand monoclonal antibody being evaluated by the Company in an early-stage clinical trial. Under the terms of the agreement, Merck and Falk have discontinued their collaboration based on their existing co-development contract resulting in Merck having secured global rights to MK-8690. In exchange, Falk will receive a $150 million upfront payment, which the Company will record as a charge to Research and development expenses in the fourth quarter of 2025. Falk is also eligible to receive a developmental milestone payment, as well as tiered low-single-digit royalties on sales in certain territories.
In October 2025, Merck acquired Verona Pharma plc (Verona Pharma), a biopharmaceutical company focused on respiratory diseases, for total consideration of approximately $10.5 billion (including payments to settle share-based equity awards). Through this acquisition, Merck acquired Ohtuvayre (ensifentrine), a first-in-class selective dual inhibitor of phosphodiesterases 3 and 4 (PDE3 and PDE4), which was approved in the U.S. in June 2024 for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in adult patients and is also being evaluated in clinical trials for the treatment of non-cystic fibrosis bronchiectasis. The Company is in the process of determining the fair value of assets acquired and liabilities assumed in this transaction; however, it expects to capitalize most of the purchase price as an intangible asset for Ohtuvayre. There are no future contingent payments associated with the acquisition.
Also in October 2025, Merck and Blackstone Life Sciences (Blackstone) entered into a funding arrangement under which Blackstone will pay Merck $700 million (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. The funding will be recognized as a reduction to Research and development expenses as Merck incurs applicable development costs for the sac-TMT program. 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 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 new agreement with Blackstone. Merck will retain 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 will not receive any rights to sac-TMT. 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.
In July 2025, the technology transfer for MK-2010 (LM-299), a novel investigational PD-1/vascular endothelial growth factor (VEGF) bispecific antibody that was licensed from LaNova Medicines Ltd (LaNova) in 2024, was completed. Accordingly, Merck made a $300 million payment to LaNova (which has been acquired by Sino Biopharmaceutical Limited) that was recorded as a charge to Research and development expenses in the third quarter and first nine months of 2025.
In May 2025, Merck and Jiangsu Hengrui Pharmaceuticals Co., Ltd. (Hengrui Pharma) closed an exclusive license agreement for MK-7262 (HRS-5346), an investigational oral small molecule Lipoprotein(a) inhibitor, which is currently being evaluated in a Phase 2 clinical trial in China. Under the agreement, Hengrui Pharma granted Merck exclusive rights to develop, manufacture and commercialize MK-7262 (HRS-5346) worldwide, excluding the Greater China region. The agreement provided for an upfront payment of $200 million, which was recorded as a charge to Research and development expenses in the first nine months of 2025. Hengrui Pharma is also eligible to receive future contingent developmental milestone payments of up to $92.5 million, regulatory milestone payments of up to $177.5 million, and sales-based milestone payments of up to $1.5 billion, as well as tiered royalties ranging from a mid-single-digit rate to a low-double-digit rate on future net sales of MK-7262 (HRS-5346), if approved.
In March 2025, Merck acquired the Dundalk, Ireland facility of WuXi Vaccines (a wholly owned subsidiary of WuXi Biologics), which was accounted for as an asset acquisition. Merck paid $437 million at closing which, combined with previous consideration transferred under a prior manufacturing arrangement with WuXi Vaccines related to this facility, resulted in $759 million being recorded as assets under construction within Property, Plant and Equipment. There are no future contingent payments associated with the acquisition.
2024 Transactions
In September 2024, Merck acquired MK-1045 (formally CN201), a novel investigational clinical-stage bispecific antibody for the treatment of B-cell associated diseases, from Curon Biopharmaceutical (Curon) for an upfront payment of $700 million. In addition, Curon is eligible to receive future contingent developmental milestone payments of up to $300 million and regulatory milestone payments of up to $300 million. The transaction was accounted for as an asset acquisition. Merck recorded a charge of $750 million (reflecting the upfront payment and other related costs) to Research and development expenses in the third quarter and first nine months of 2024 related to the execution of the transaction. In connection with the agreement, Merck is also obligated to pay a third party future contingent developmental, regulatory and sales-based milestone payments of up to $128 million in the aggregate, as well as tiered royalties ranging from a mid-single-digit rate to a low-double-digit rate on future net sales of MK-1045, if approved.
In July 2024, Merck acquired the aqua business of Elanco Animal Health Incorporated (Elanco aqua business) for total consideration of $1.3 billion. The Elanco aqua business consists of an innovative portfolio of medicines and vaccines, nutritionals and supplements for aquatic species; two related aqua manufacturing facilities in Canada and Vietnam; as well as a research facility in Chile. The acquisition broadens Animal Health’s aqua portfolio with products, such as Clynav, a new generation DNA-based vaccine that protects Atlantic salmon against pancreas disease, and Imvixa, an anti-parasitic sea lice treatment. This acquisition also brings a portfolio of water treatment products for warm water production, complementing Animal Health’s warm water vaccine portfolio. In addition to these products, the DNA-based vaccine technology that is a part of the business has the potential to accelerate the development of novel vaccines to address the unmet needs of the aqua industry. There are no contingent payments associated with the acquisition, which was accounted for as a business combination.
The estimated fair values of assets acquired and liabilities assumed from the Elanco aqua business (inclusive of measurement period adjustments) are as follows:
($ in millions)
July 9, 2024
Inventories
$65 
Property, plant and equipment
66 
Product rights - Clynav (useful life 15 years) (1)
340 
Other product rights (useful lives 15 years) (1)
291 
Deferred tax asset
106 
Other assets and liabilities, net23 
Total identifiable net assets891 
Goodwill (2)
412 
Consideration transferred$1,303 
(1)     The estimated fair values of Clynav and other product rights were determined using an income approach, specifically the multi-period excess earnings method. The future probability-weighted net cash flows were discounted to present value utilizing a discount rate of 8.5%. Actual cash flows are likely to be different than those assumed.
(2)    The goodwill recognized is largely attributable to anticipated synergies expected to arise after the acquisition and was allocated to the Animal Health segment. This amount is expected to be deductible for tax purposes.
Also in July 2024, Merck acquired Eyebiotech Limited (EyeBio), a privately held ophthalmology-focused biotechnology company for $1.2 billion (including payments to settle share-based equity awards) and also incurred $207 million of transaction costs. The acquisition agreement also provides for former EyeBio shareholders to receive contingent developmental milestone payments of up to $1.0 billion (of which $200 million has since been paid associated with the achievement of milestones as noted below), regulatory milestone payments of up to $200 million and sales-based milestone payments of up to $500 million. EyeBio’s development work focused on candidates for the prevention and treatment of vision loss associated with retinal vascular leakage, a known risk factor for retinal diseases. EyeBio’s lead candidate, MK-3000 (formerly EYE103), is an investigational, potentially first-in-class tetravalent, tri-specific antibody that acts as an agonist of the Wingless-related integration site signaling pathway, which is in clinical development for the treatment of diabetic macular edema and neovascular age-related macular degeneration. The transaction was accounted for as an asset acquisition since MK-3000 accounted for substantially all of the fair value of the gross assets acquired (excluding cash and deferred income taxes). Merck recorded net assets of $21 million, as well as a charge of $1.35 billion to Research and development expenses in the third quarter and first nine months of 2024 related to the acquisition. Additionally, a $100 million developmental milestone was recorded as a charge to Research and development expenses in the third quarter and first nine months of 2024 and an additional $100 million developmental milestone was charged to Research and development expenses in the first nine months of 2025.
In March 2024, Merck acquired Harpoon Therapeutics, Inc. (Harpoon), a clinical-stage immunotherapy company developing a novel class of T-cell engagers designed to harness the power of the body’s immune system to treat patients suffering from cancer and other diseases, for $765 million and also incurred $56 million of transaction costs. Harpoon’s lead candidate, gocatamig (MK-6070, formerly HPN328), is a T-cell engager targeting delta-like ligand 3 (DLL3), an inhibitory canonical Notch ligand that is expressed at high levels in small cell lung cancer and neuroendocrine tumors. The transaction was accounted for as an asset acquisition since gocatamig represented substantially all of the fair value of the gross assets acquired (excluding cash and deferred income taxes). Merck recorded net assets of $165 million, as well as a charge of $656 million to Research and development expenses in the first nine months of 2024 related to the transaction. There are no future contingent payments associated with the acquisition. In August 2024, Merck and Daiichi Sankyo expanded their existing global co-development and co-commercialization agreement to include gocatamig. See Note 3 for more information on Merck’s collaboration with Daiichi Sankyo.
In February 2024, Merck and Alteogen Inc. (Alteogen) converted their existing non-exclusive license agreement into an exclusive license for the use of Alteogen’s proprietary berahyaluronidase alfa for the formulation of subcutaneous pembrolizumab. Pursuant to the amended agreement, Alteogen is eligible to receive regulatory approval milestone payments of up to $51 million, as well as annual and cumulative sales-based milestone payments of up to $1.0 billion in the aggregate. After the achievement of all sales-based milestones, a 2% royalty on net sales is payable to Alteogen. In September 2025, the U.S. Food and Drug Administration (FDA) approved Keytruda Qlex (pembrolizumab and berahyaluronidase alfa-pmph) injection, which triggered regulatory milestone payments of $25 million in the aggregate from Merck to Alteogen. Additionally, following FDA approval, the Company determined that it was probable that sales of Keytruda Qlex in the future would trigger $680 million of sales-based milestone payments from Merck to Alteogen. Accordingly, in the third quarter of 2025, Merck recorded a $705 million liability for these regulatory and sales-based milestone payments and a corresponding intangible asset related to Keytruda Qlex included in Other Intangibles, Net. The intangible asset will be amortized over its estimated useful life through December 2030. The $25 million of regulatory milestone payments were made in October 2025; the future sales-based milestone payments will be paid upon achievement of the corresponding milestone.
v3.25.3
Collaborative Arrangements
9 Months Ended
Sep. 30, 2025
Collaborative Arrangements [Abstract]  
Collaborative Arrangements Collaborative Arrangements
Merck has entered into collaborative arrangements that provide the Company with varying rights to develop, produce and market products together with its collaborative partners. Both parties in these arrangements are active participants and exposed to significant risks and rewards dependent on the commercial success of the activities of the collaboration. Merck’s more significant collaborative arrangements are discussed below.
AstraZeneca PLC
In 2017, Merck and AstraZeneca PLC (AstraZeneca) entered into a global strategic oncology collaboration to co-develop and co-commercialize AstraZeneca’s Lynparza (olaparib) for multiple cancer types. Independently, Merck and AstraZeneca are developing and commercializing Lynparza in combinations with their respective PD-1 and PD-L1 medicines, Keytruda (pembrolizumab) and Imfinzi. 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 simplified 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 may receive future payments of $150 million in each of January 2026 and January 2027, and $100 million in January 2028, subject to an annual election by AstraZeneca. Additionally, the amended agreement provides for Merck to receive contingent regulatory and sales-based milestone payments, as well as mid-single-digit royalties on future net sales. Koselugo received a regulatory approval in August 2025 triggering a milestone payment (due from AstraZeneca in 2026) of $50 million (which was recorded within Sales as alliance revenue in the third quarter of 2025) and another regulatory approval in October 2025 triggering an additional milestone payment (due from AstraZeneca in 2027) of $50 million (which will be recorded within Sales as alliance revenue in the fourth quarter of 2025). Merck remains eligible to receive future contingent payments for the achievement of regulatory milestones of up to $75 million and sales-based milestones of up to $235 million. AstraZeneca has the option 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 nine months 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. Lynparza received a regulatory approval triggering a capitalized milestone payment from Merck to AstraZeneca of $245 million in the first nine months of 2024 (which had been previously accrued for). The partners have agreed that no future regulatory milestone payments from Merck to AstraZeneca are likely.
The intangible asset balances related to Lynparza and Koselugo (which reflect the capitalized sales-based and regulatory milestone payments attributed to each product) were $926 million and $41 million, respectively, at September 30, 2025 and are included in Other Intangibles, Net. The assets are being amortized over their estimated useful lives (through 2028 for Lynparza and through 2029 for Koselugo) as supported by projected future cash flows, subject to impairment testing.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Alliance revenue - Lynparza$379 $337 $1,061 $947 
Alliance revenue - Koselugo (1)
214 39 301 114 
Total alliance revenue$593 $376 $1,362 $1,061 
Cost of sales (2)
84 82 253 245 
Selling, general and administrative31 39 103 121 
Research and development19 31 57 
($ in millions)September 30, 2025December 31, 2024
Receivables from AstraZeneca included in Other current assets (3)
$436 $424 
Payables to AstraZeneca included in Accrued and other current liabilities (4)
713 
(1)    Amounts in 2025 include the $150 million upfront payment and $50 million regulatory milestone triggered in the third quarter as a result of the amendment to the collaboration agreement noted above.
(2)    Represents amortization of capitalized milestone payments.
(3)    Balance at September 30, 2025 includes a milestone receivable.
(4)    Balance at December 31, 2024 includes accrued milestone payments.
Eisai Co., Ltd.
In 2018, Merck and Eisai Co., Ltd. (Eisai) announced a strategic collaboration for the worldwide co-development and co-commercialization of Lenvima (lenvatinib), an orally available tyrosine kinase inhibitor discovered by Eisai. Under the agreement, Merck and Eisai are developing and commercializing Lenvima jointly, both as monotherapy and in combination with Keytruda. Eisai records Lenvima product sales globally (Eisai is the principal on Lenvima sales transactions) and Merck and Eisai share applicable profits equally. Merck records its share of Lenvima product sales, net of cost of sales and commercialization costs, as alliance revenue. Expenses incurred during co-development are shared by the two companies in accordance with the collaboration agreement and reflected in Research and development expenses. Certain expenses incurred solely by Merck or Eisai are not shareable under the collaboration agreement, including costs incurred in excess of agreed upon caps, and costs related to certain combination studies of Keytruda and Lenvima, 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.
In the first nine months of 2024, Merck made a $125 million sales-based milestone payment to Eisai (which had been previously accrued for). Potential future sales-based milestone payments of $2.3 billion have not yet been accrued as they are not deemed by the Company to be probable at this time. There are no regulatory milestone payments remaining under the agreement.
The intangible asset balance related to Lenvima (which includes capitalized sales-based and regulatory milestone payments) was $261 million at September 30, 2025 and is included in Other Intangibles, Net. The amount is being amortized over its estimated useful life through 2026 as supported by projected future cash flows, subject to impairment testing.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Alliance revenue - Lenvima$258 $251 $781 $755 
Cost of sales (1)
60 60 181 181 
Selling, general and administrative33 40 99 120 
Research and development10 18 
($ in millions)September 30, 2025December 31, 2024
Receivables from Eisai included in Other current assets
$258 $257 
(1)    Represents amortization of capitalized milestone payments.
Bayer AG
In 2014, the Company entered into a worldwide clinical development collaboration with Bayer AG (Bayer) to market and develop soluble guanylate cyclase (sGC) modulators including Bayer’s Adempas (riociguat) and Verquvo (vericiguat). The two companies have implemented a joint development and commercialization strategy. Under the agreement, Bayer
commercializes Adempas in the Americas, while Merck commercializes in the rest of the world. For Verquvo, Merck commercializes in the U.S. and Bayer commercializes in the rest of the world. Both companies share in development costs and profits on sales. Merck records sales of Adempas and Verquvo in its marketing territories, as well as alliance revenue. Alliance revenue represents Merck’s share of profits from sales of Adempas and Verquvo in Bayer’s marketing territories, which are product sales net of cost of sales and commercialization costs. Cost of sales includes Bayer’s share of profits from sales in Merck’s marketing territories.
In addition, the agreement provided for contingent payments from Merck to Bayer related to the successful achievement of sales-based milestones. There are no sales-based milestone payments remaining under this collaboration.
The intangible asset balances related to Adempas (which includes the acquired intangible asset balance, as well as capitalized sales-based milestone payments attributed to Adempas) and Verquvo (which reflects the portion of the final sales-based milestone payment that was attributed to Verquvo) were $312 million and $41 million, respectively, at September 30, 2025 and are included in Other Intangibles, Net. The assets are being amortized over their estimated useful lives (through 2027 for Adempas and through 2031 for Verquvo) as supported by projected future cash flows, subject to impairment testing.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Alliance revenue - Adempas/Verquvo$112 $102 $340 $306 
Net sales of Adempas recorded by Merck82 72 229 214 
Net sales of Verquvo recorded by Merck12 11 33 25 
Total sales$206 $185 $602 $545 
Cost of sales (1)
71 59 190 182 
Selling, general and administrative22 29 80 88 
Research and development11 27 55 82 
($ in millions)September 30, 2025December 31, 2024
Receivables from Bayer included in Other current assets
$168 $160 
Payables to Bayer included in Accrued and other current liabilities
93 82 
(1)    Includes amortization of intangible assets, cost of products sold by Merck, as well as Bayer’s share of profits from sales in Merck’s marketing territories.
Ridgeback Biotherapeutics LP
In 2020, Merck and Ridgeback Biotherapeutics LP (Ridgeback), a closely held biotechnology company, entered into a collaboration agreement to develop Lagevrio (molnupiravir), an investigational orally available antiviral candidate for the treatment of patients with COVID-19. Merck gained exclusive worldwide rights to develop and commercialize Lagevrio and related molecules. Following initial authorizations in certain markets in 2021, Lagevrio has since received multiple additional authorizations.
Under the terms of the agreement, Ridgeback received an upfront payment and is eligible to receive future contingent payments dependent upon the achievement of certain developmental and regulatory approval milestones. The agreement also provides for Merck to reimburse Ridgeback for a portion of certain third-party contingent milestone payments and royalties on net sales, which is part of the profit-sharing calculation. Merck is the principal on sales transactions, recognizing sales and related costs, with profit-sharing amounts recorded within Cost of sales. Profits from the collaboration are split equally between the partners. Reimbursements from Ridgeback for its share of research and development costs (deducted from Ridgeback’s share of profits) are reflected as decreases to Research and development expenses.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Net sales of Lagevrio recorded by Merck
$138 $383 $323 $843 
Cost of sales (1)
81 204 178 491 
Selling, general and administrative
11 11 39 43 
Research and development
11 25 
($ in millions)September 30, 2025December 31, 2024
Payables to Ridgeback included in Accrued and other current liabilities (2)
$49 $68 
(1)    Includes cost of products sold by Merck, Ridgeback’s share of profits, royalty expense, amortization of capitalized milestone payments and inventory reserves.
(2)    Includes accrued royalties.
Daiichi Sankyo
In 2023, Merck and Daiichi Sankyo entered into a global development and commercialization agreement for three of Daiichi Sankyo’s DXd ADC candidates: patritumab deruxtecan (HER3-DXd) (MK-1022), ifinatamab deruxtecan (I-DXd) (MK-2400) and raludotatug deruxtecan (R-DXd) (MK-5909). All three potentially first-in-class DXd ADCs are in various stages of clinical development for the treatment of multiple solid tumors both as monotherapy and/or in combination with other treatments. The companies will jointly develop and potentially commercialize these ADC candidates worldwide, except in Japan where Daiichi Sankyo will maintain exclusive rights. Daiichi Sankyo will be solely responsible for manufacturing and supply.
Under the terms of the agreement, Merck made payments to Daiichi Sankyo totaling $4.0 billion in 2023. These payments included $1.0 billion ($500 million each for patritumab deruxtecan and ifinatamab deruxtecan), which may be refundable on a pro-rated basis in the event of early termination of development with respect to either program. In addition, the agreement provided for a continuation payment of $750 million related to patritumab deruxtecan (which Merck paid in October 2024) and a continuation payment of $750 million related to raludotatug deruxtecan (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. In conjunction with this transaction, Merck recorded an aggregate pretax charge of $5.5 billion to Research and development expenses in 2023 for the $4.0 billion of upfront payments and the $1.5 billion of continuation payments.
Merck and Daiichi Sankyo equally share research and development costs, except for raludotatug deruxtecan, where Merck is responsible for 75% of the first $2.0 billion of research and development expenses. Merck includes its share of development costs associated with the collaboration as part of Research and development expenses. Following regulatory approval, Daiichi Sankyo will generally record sales worldwide (Daiichi Sankyo will be the principal on sales transactions) and the companies will equally share expenses as well as profits worldwide except for Japan where Daiichi Sankyo retains exclusive rights and Merck will receive a 5% sales-based royalty. Merck will record its share of product sales, net of cost of sales and commercialization costs, as alliance revenue.
In August 2024, Merck and Daiichi Sankyo expanded their agreement to include gocatamig (MK-6070), an investigational DLL3 targeting T-cell engager, which Merck obtained through its acquisition of Harpoon (see Note 2). The companies are planning to evaluate gocatamig in combination with ifinatamab deruxtecan in certain patients with small cell lung cancer, as well as other potential combinations. Merck received an upfront cash payment of $170 million from Daiichi Sankyo (recorded within Other (income) expense, net) and has also satisfied a contingent quid obligation from the original collaboration agreement. The companies will jointly develop and commercialize gocatamig worldwide and share research and development, as well as commercialization expenses. Research and development expenses related to gocatamig in combination with ifinatamab deruxtecan will be shared in a manner consistent with the original agreement for ifinatamab deruxtecan. Merck will be solely responsible for manufacturing and supply of gocatamig. If approved, Merck will generally record sales for gocatamig worldwide (Merck will be the principal on sales transactions) and the companies will equally share expenses as well as profits worldwide, except for Japan where Merck retains exclusive rights and Daiichi Sankyo will receive a 5% sales-based royalty.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Cost of sales (1)
$67 $— $67 $— 
Selling, general and administrative 21 21 
Research and development
110 94 379 227 
($ in millions)September 30, 2025December 31, 2024
Receivables from Daiichi Sankyo included in Other current assets
$17 $
Payables to Daiichi Sankyo included in Accrued and other current liabilities (2)
869 817 
(1)    Represents Merck’s share of certain inventory-related costs.
(2)    Includes accrued continuation payment.
Moderna, Inc.
In 2022, Merck exercised its option to jointly develop and commercialize intismeran autogene (V940/mRNA-4157), an investigational individualized neoantigen therapy, pursuant to the terms of an existing collaboration and license agreement with Moderna, Inc. (Moderna). Intismeran autogene is currently being evaluated in combination with Keytruda in multiple 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 $235 million of shared facility costs at September 30, 2025, primarily reflected within Other Assets. These costs are amortized over the assets’ estimated useful lives.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Selling, general and administrative $$$19 $11 
Research and development (1)
96 93 272 255 
($ in millions)September 30, 2025December 31, 2024
Payables to Moderna included in Accrued and other current liabilities
$13 $57 
(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; however, Merck co-promotes Reblozyl (and may co-promote any future products approved under this collaboration) in North America, which is reimbursed by BMS. Merck receives tiered royalties ranging from 20% to 24% based on sales levels. This royalty will be reduced by 50% upon the earlier of patent expiry or generic entry on an indication-by-indication basis in each market. Additionally, Merck is eligible to receive future contingent sales-based milestone payments of up to $80 million. Alliance revenue related to this collaboration, consisting of royalties (recorded within Sales), was $136 million and $361 million in the third quarter and first nine months of 2025, respectively, compared with $100 million and $261 million in the third quarter and first nine months of 2024, respectively.
v3.25.3
Restructuring
9 Months Ended
Sep. 30, 2025
Restructuring and Related Activities [Abstract]  
Restructuring Restructuring
In July 2025, the Company approved a new restructuring program (2025 Restructuring Program) designed to position the Company for its next chapter of growth and to successfully advance its pipeline and launch new products across multiple therapeutic areas. As part of this program, the Company expects to eliminate certain positions in sales and administrative organizations, as well as research and development. The Company will, however, continue to hire employees into new roles across all strategic growth areas of the business. In addition, the Company will reduce its global real estate footprint and continue to optimize its manufacturing network, aligning the geography of its global manufacturing footprint to its customers and reflecting changes in the Company’s business. Most actions contemplated under the 2025 Restructuring Program are expected to be largely completed by the end of 2027, with the exception of certain manufacturing actions, which are expected to be substantially completed by the end of 2029. The cumulative pretax costs to be incurred by the Company to implement the program are estimated to be approximately $3.0 billion, of which approximately 60% will be cash, relating primarily to employee separation expense and contractual termination costs. The remainder of the costs will be non-cash, relating primarily to the accelerated depreciation of facilities. The Company recorded total pretax costs of $302 million and $951 million in the third quarter and first nine months of 2025, respectively, related to the 2025 Restructuring Program.
In January 2024, the Company approved a restructuring program (2024 Restructuring Program) intended to continue the optimization of the Company’s Human Health global manufacturing network as the future pipeline shifts to new modalities and also optimize the Animal Health global manufacturing network to improve supply reliability and increase efficiency. The actions contemplated under the 2024 Restructuring Program are expected to be substantially completed by the end of 2031, with the cumulative pretax costs to be incurred by the Company to implement the program estimated to be approximately $4.0 billion. Approximately 60% of the cumulative pretax costs will be non-cash, relating primarily to the accelerated depreciation of facilities to be closed or divested. The remainder of the costs will result in cash outlays, relating primarily to facility shut-down costs. The Company recorded total pretax costs of $88 million and $279 million in the third quarter of 2025 and 2024, respectively, and $323 million and $701 million in the first nine months of 2025 and 2024, respectively, related to the 2024 Restructuring Program. Since inception of the 2024 Restructuring Program through September 30, 2025, Merck has incurred total cumulative pretax costs of $1.4 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 September 30, 2025Nine Months Ended September 30, 2025
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
Accelerated
Depreciation
Separation Costs
Other Exit Costs
Total
2025 Restructuring Program
Cost of sales$— $— $72 $72 $— $— $172 $172 
Research and development— — 233 233 — — 286 286 
Restructuring costs— — (3)(3)— 481 12 493 
— — 302 302 — 481 470 951 
2024 Restructuring Program
Cost of sales56 — (18)38 152 — (13)139 
Selling, general and administrative— — — — — — 
Restructuring costs— 44 50 — 13 170 183 
56 26 88 152 13 158 323 
$56 $$328 $390 $152 $494 $628 $1,274 
 Three Months Ended September 30, 2024Nine Months Ended September 30, 2024
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
Accelerated
Depreciation
Separation Costs
Other Exit Costs
Total
2024 Restructuring Program
Cost of sales$40 $— $152 $192 $171 $— $203 $374 
Selling, general and administrative— — 31 31 — — 67 67 
Research and development— — — — — — 
Restructuring costs— 11 45 56 — 122 136 258 
$40 $11 $228 $279 $171 $122 $408 $701 
Accelerated depreciation costs primarily relate to manufacturing, research and administrative facilities to be fully or partially closed or divested and equipment to be disposed of as part of the programs. Accelerated depreciation costs represent the difference between the depreciation expense to be recognized over the revised useful life of the asset, based upon the anticipated date the site will be closed or divested or the equipment disposed of, and depreciation expense as determined utilizing the useful life prior to the restructuring actions. All the sites will continue to operate up through the respective closure dates and, since future undiscounted cash flows are sufficient to recover the respective book values, Merck is recording accelerated depreciation over the revised useful life of the site assets. Anticipated site closure dates, particularly related to manufacturing locations, have been and may continue to be adjusted to reflect changes resulting from regulatory or other factors.
Separation costs are associated with actual headcount reductions, as well as involuntary headcount reductions which were probable and could be reasonably estimated.
Other exit costs in 2025 and 2024 include asset impairment, facility shut-down, contractual termination, and other related costs, as well as pretax gains and losses resulting from the sales of facilities and related assets. Additionally, other activity includes certain employee-related costs associated with pension and other postretirement benefit plans (see Note 10) and share-based compensation.
The following table summarizes the charges and spending related to restructuring program activities for the nine months ended September 30, 2025:
($ in millions)
Accelerated Depreciation
Separation
Costs
Other Exit Costs
Total
2025 Restructuring Program
Restructuring reserves January 1, 2025
$— $— $— $— 
Expenses
— 481 470 951 
(Payments) receipts, net— (7)(2)(9)
Non-cash activity— — (81)(81)
Restructuring reserves September 30, 2025
$— $474 $387 $861 
2024 Restructuring Program
Restructuring reserves January 1, 2025
$— $564 $— $564 
Expenses152 13 158 323 
(Payments) receipts, net— (78)(161)(239)
Non-cash activity(152)— (149)
Restructuring reserves September 30, 2025
$— $499 $— $499 
v3.25.3
Financial Instruments
9 Months Ended
Sep. 30, 2025
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Financial Instruments Financial Instruments
Derivative Instruments and Hedging Activities
The Company manages the impact of foreign exchange rate movements and interest rate movements on its earnings, cash flows and fair values of assets and liabilities through operational means and through the use of various financial instruments, including derivative instruments.
A significant portion of the Company’s revenues and earnings in foreign affiliates is exposed to changes in foreign exchange rates. The objectives of and accounting related to the Company’s foreign currency risk management program, as well as its interest rate risk management activities are discussed below.
Foreign Currency Risk Management
The Company has established revenue hedging, balance sheet risk management and net investment hedging programs to protect against volatility of future foreign currency cash flows and changes in fair value caused by changes in foreign exchange rates.
The objective of the revenue hedging program is to reduce the variability caused by changes in foreign exchange rates that would affect the U.S. dollar value of future cash flows derived from foreign currency denominated sales, primarily the euro, Japanese yen and Chinese renminbi. To achieve this objective, the Company will hedge a portion of its forecasted foreign currency denominated third-party and intercompany distributor entity sales (forecasted sales) that are expected to occur over its planning cycle, typically no more than two years into the future. The Company will layer in hedges over time, increasing the portion of forecasted sales hedged as it gets closer to the expected date of the forecasted sales. The portion of forecasted sales hedged is based on assessments of cost-benefit profiles that consider natural offsetting exposures, revenue and foreign exchange rate volatilities and correlations, and the cost of hedging instruments. The Company manages its anticipated transaction exposure principally with purchased local currency put options, forward contracts, and purchased collar options.
The fair values of these derivative contracts are recorded as either assets (gain positions) or liabilities (loss positions) in the Condensed Consolidated Balance Sheet. Changes in the fair value of derivative contracts are recorded each period in either current earnings or Other comprehensive income (OCI), depending on whether the derivative is designated as part of a hedge transaction and, if so, the type of hedge transaction. For derivatives that are designated as cash flow hedges, the unrealized gains or losses on these contracts are recorded in Accumulated Other Comprehensive Loss (AOCL) and reclassified into Sales when the hedged anticipated revenue is recognized. The amount reclassified into earnings as a result of the discontinuation of cash flow hedges because it was no longer deemed probable the forecasted hedged transactions would occur was not material for the third quarter or first nine months of either 2025 or 2024. For those derivatives which are not designated as cash flow hedges, but serve as economic hedges of forecasted sales, unrealized gains or losses are recorded in Sales each period. The cash flows from both designated and non-designated contracts are reported as operating activities in the Condensed Consolidated Statement of Cash Flows. The Company does not enter into derivatives for trading or speculative purposes.
The Company manages operating activities and net asset positions at each local subsidiary in order to mitigate the effects of foreign exchange on monetary assets and liabilities. Monetary assets and liabilities denominated in a currency other than the functional currency of a given subsidiary are remeasured at spot rates in effect on the balance sheet date with the effects of changes in spot rates reported in Other (income) expense, net. The Company also uses a balance sheet risk management program to mitigate the exposure of such assets and liabilities from the effects of volatility in foreign exchange. Merck principally utilizes forward exchange contracts to offset the effects of foreign exchange on exposures when it is deemed economical to do so based on a cost-benefit analysis that considers the magnitude of the exposure, the volatility of the foreign exchange rate and the cost of the hedging instrument (primarily the euro, Swiss franc, Japanese yen, and Chinese renminbi). The forward contracts are not designated as hedges and are marked to market through Other (income) expense, net. Accordingly, fair value changes in the forward contracts help mitigate the changes in the value of the remeasured assets and liabilities attributable to changes in foreign currency exchange rates, except to the extent of the spot-forward differences. These differences are not significant due to the short-term nature of the contracts, which typically have average maturities at inception of less than six months. The cash flows from these contracts are reported as operating activities in the Condensed Consolidated Statement of Cash Flows.
The Company also uses forward exchange contracts to hedge a portion of its net investment in foreign operations against movements in foreign exchange rates. The forward contracts are designated as hedges of the net investment in a foreign operation. The unrealized gains or losses on these contracts are recorded in foreign currency translation adjustment within OCI and remain in AOCL until either the sale or complete or substantially complete liquidation of the subsidiary. The Company excludes certain portions of the change in fair value of its derivative instruments from the assessment of hedge effectiveness (excluded components). Changes in fair value of the excluded components are recognized in OCI. The Company recognizes in earnings the initial value of the excluded components on a straight-line basis over the life of the derivative instrument, rather than using the mark-to-market approach. The cash flows from these contracts are reported as investing activities in the Condensed Consolidated Statement of Cash Flows.
Foreign exchange risk is also managed through the use of foreign currency debt. Certain of the Company’s senior unsecured euro-denominated notes have been designated as, and are effective as, economic hedges of the net investment in a foreign operation. Accordingly, foreign currency transaction gains or losses due to spot rate fluctuations on the euro-denominated debt instruments are included in foreign currency translation adjustment within OCI.
The effects of the Company’s net investment hedges on OCI and the Condensed Consolidated Statement of Income are shown below:
Amount of Pretax (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 September 30,Nine Months Ended September 30,Three Months Ended September 30,Nine Months Ended September 30,
($ in millions)20252024202520242025202420252024
Net Investment Hedging Relationships
Foreign exchange contracts$(20)$$45 $$(3)$— $(11)$(2)
Euro-denominated notes(1)169 540 73 — — — — 
(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 September 30, 2025, the Company was a party to seven pay-floating, receive-fixed interest rate swap contracts designated as fair value hedges of a portion of fixed-rate notes as detailed in the table below.
September 30, 2025
($ in millions)
Par Value of Debt
Number of Interest Rate Swaps Held
Total Swap Notional Amount
4.50% notes due 2033
$1,500 $1,500 
    5.00% notes due 2053
1,500 250
The interest rate swap contracts are designated hedges of the fair value changes in the notes attributable to changes in the benchmark Secured Overnight Financing Rate (SOFR) swap rate. The fair value changes in the notes attributable to changes in the SOFR swap rate are recorded in interest expense along with the offsetting fair value changes in the swap contracts. The cash flows from these contracts are reported as operating activities in the Condensed Consolidated Statement of Cash Flows.
The table below presents the location of amounts recorded in the Condensed Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges:
Carrying Amount of Hedged Liabilities
Cumulative Amount of Fair Value Hedging Adjustment Increase Included in the Carrying Amount
($ in millions)
September 30, 2025December 31, 2024September 30, 2025December 31, 2024
Balance Sheet Caption
Long-Term Debt
$1,819 $1,509 $80 $17 

Presented in the table below is the fair value of derivatives on a gross basis segregated between those derivatives that are designated as hedging instruments and those that are not designated as hedging instruments:
  September 30, 2025December 31, 2024
  Fair Value of DerivativeU.S. Dollar
Notional
Fair Value of DerivativeU.S. Dollar
Notional
($ in millions)AssetLiabilityAssetLiability
Derivatives Designated as Hedging InstrumentsBalance Sheet Caption
Interest rate swap contracts
Other Assets
$80 $— $1,750 $17 $— $1,500 
Foreign exchange contractsOther current assets55 — 4,681 323 — 8,662 
Foreign exchange contractsOther Assets37 — 2,274 66 — 2,125 
Foreign exchange contractsAccrued and other current liabilities— 246 5,694 — 162 
Foreign exchange contractsOther Noncurrent Liabilities— — — — 16 
  $172 $246 $14,399 $406 $$12,465 
Derivatives Not Designated as Hedging InstrumentsBalance Sheet Caption      
Foreign exchange contractsOther current assets$144 $— $12,498 $323 $— $12,544 
Foreign exchange contractsAccrued and other current liabilities— 246 15,975 — 343 13,551 
  $144 $246 $28,473 $323 $343 $26,095 
  $316 $492 $42,872 $729 $345 $38,560 
As noted above, the Company records its derivatives on a gross basis in the Condensed Consolidated Balance Sheet. The Company has master netting agreements with several of its financial institution counterparties (see Concentrations of Credit Risk below). The following table provides information on the Company’s derivative positions subject to these master netting arrangements as if they were presented on a net basis, allowing for the right of offset by counterparty and cash collateral exchanged per the master agreements and related credit support annexes:
 September 30, 2025December 31, 2024
($ in millions)AssetLiabilityAssetLiability
Gross amounts recognized in the condensed consolidated balance sheet$316 $492 $729 $345 
Gross amounts subject to offset in master netting arrangements not offset in the condensed consolidated balance sheet(246)(246)(299)(299)
Cash collateral received
(1)— (165)— 
Net amounts$69 $246 $265 $46 
The table below provides information regarding the location and amount of pretax gains and losses of derivatives designated in fair value or cash flow hedging relationships:
Three Months Ended September 30,Nine Months Ended September 30,
($ in millions)202520242025202420252024202520242025202420252024
Financial Statement Caption in which Effects of Fair Value or Cash Flow
Hedges are Recorded
Sales
Other (income) expense, net (1)
Other comprehensive income (loss)Sales
Other (income) expense, net (1)
Other comprehensive income (loss)
$17,276 $16,657 $(238)$(162)$219 $(10)$48,611 $48,544 $(281)$(151)$(257)$(210)
Loss (gain) on fair value hedging relationships:
Interest rate swap contracts
Hedged items— — 68 — — — — 62 42 — — 
Derivatives designated as hedging instruments— — (5)(69)— — — — (63)(43)— — 
Impact of cash flow hedging relationships:
Foreign exchange contracts
Amount of gain (loss) recognized in OCI on derivatives
— — — — 113 (325)— — — — (630)22 
(Decrease) increase in Sales as a result of AOCL reclassifications
(85)48 — — 85 (48)(35)146 — — 35 (146)
Interest rate contracts
Amount of gain recognized in Other (income) expense, net on derivatives
— — — — — — — — (1)(1)— — 
Amount of gain (loss) recognized in OCI on derivatives
— — — — 18 — — — — — 17 (1)
(1)    Interest expense is a component of Other (income) expense, net.
The table below provides information regarding the income statement effects of derivatives not designated as hedging instruments:
Amount of Derivative Pretax Loss (Gain) Recognized in Income
Three Months Ended September 30,Nine Months Ended September 30,
($ in millions)2025202420252024
Derivatives Not Designated as Hedging InstrumentsIncome Statement Caption
Foreign exchange contracts (1)
Other (income) expense, net$39 $(139)$(217)$(65)
Foreign exchange contracts (2)
Sales(8)10 26 (10)
(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 September 30, 2025, the Company estimates $298 million of pretax net unrealized losses on derivatives maturing within the next 12 months that hedge foreign currency denominated sales over that same period will be reclassified from AOCL to Sales. The amount ultimately reclassified to Sales may differ as foreign exchange rates change. Realized gains and losses are ultimately determined by actual foreign exchange rates at maturity.
Investments in Debt and Equity Securities
Information on investments in debt and equity securities is as follows:
 September 30, 2025December 31, 2024
 Amortized
Cost
Gross UnrealizedFair
Value
Amortized
Cost
Gross UnrealizedFair
Value
($ in millions)GainsLossesGainsLosses
U.S. government and agency securities$99 $— $— $99 $188 $— $— $188 
Commercial paper45 — — 45 348 — — 348 
Foreign government bonds
— — — — — — 
Total debt securities$145 $— $— $145 $536 $— $— $536 
Publicly traded equity securities (1)
1,546 920 
Total debt and publicly traded equity securities$1,691 $1,456 
(1)    Unrealized net gains of $367 million and $630 million were recorded in Other (income) expense, net in the third quarter and first nine months of 2025, respectively, on equity securities still held at September 30, 2025. Unrealized net losses (gains) of $42 million and $(82) million were recorded in Other (income) expense, net in the third quarter and first nine months of 2024, respectively, on equity securities still held at September 30, 2024.
At September 30, 2025 and September 30, 2024, the Company also had $834 million and $848 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 nine months of 2025, the Company recorded unrealized gains of $1 million and unrealized losses of $33 million related to certain of these equity investments still held at September 30, 2025. During the first nine months of 2024, the Company recorded unrealized gains of $12 million and unrealized losses of $25 million related to certain of these equity investments still held at September 30, 2024. Cumulative unrealized gains and cumulative unrealized losses based on observable price changes for investments in equity investments without readily determinable fair values still held at September 30, 2025 were $293 million and $131 million, respectively.
At September 30, 2025 and September 30, 2024, the Company also had $226 million and $328 million, respectively, recorded in Other Assets for equity securities held through ownership interests in investment funds. Losses (gains) recorded in Other (income) expense, net relating to these investment funds were $2 million and $(21) million for the third quarter of 2025 and 2024, respectively, and were $53 million and $(26) million for the first nine months of 2025 and 2024, respectively.
Fair Value Measurements
Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company uses a fair value hierarchy which maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value. There are three levels of inputs used to measure fair value with Level 1 having the highest priority and Level 3 having the lowest:
Level 1 - Quoted prices (unadjusted) in active markets for identical assets or liabilities.
Level 2 - Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
Level 3 - Unobservable inputs that are supported by little or no market activity. Level 3 assets or liabilities are those whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques with significant unobservable inputs, as well as assets or liabilities for which the determination of fair value requires significant judgment or estimation.
If the inputs used to measure the financial assets and liabilities fall within more than one level described above, the categorization is based on the lowest level input that is significant to the fair value measurement of the instrument.
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis
Financial assets and liabilities measured at fair value on a recurring basis are summarized below:
Fair Value Measurements UsingFair Value Measurements Using
 Level 1Level 2Level 3TotalLevel 1Level 2Level 3Total
($ in millions)September 30, 2025December 31, 2024
Assets
Investments
Commercial paper$— $45 $— $45 $— $348 $— $348 
Foreign government bonds
— — — — — — 
U.S. government and agency securities— — — — — 99 — 99 
Publicly traded equity securities1,116 — — 1,116 463 — — 463 
 1,116 46 — 1,162 463 447 — 910 
Other assets (1)
U.S. government and agency securities99 — — 99 89 — — 89 
Publicly traded equity securities (2)
430 — — 430 457 — — 457 
529 — — 529 546 — — 546 
Derivative assets (3)
Forward exchange contracts— 169 — 169 — 499 — 499 
Interest rate swaps
— 80 — 80 — 17 — 17 
Purchased currency options— 67 — 67 — 213 — 213 
 — 316 — 316 — 729 — 729 
Total assets$1,645 $362 $— $2,007 $1,009 $1,176 $— $2,185 
Liabilities
Other liabilities
Contingent consideration$— $— $— $— $— $— $193 $193 
Derivative liabilities (3)
Forward exchange contracts— 461 — 461 — 338 — 338 
Written currency options— 31 — 31 — — 
— 492 — 492 — 345 — 345 
Total liabilities$— $492 $— $492 $— $345 $193 $538 
(1)    Investments included in other assets are restricted as to use, including for the payment of benefits under employee benefit plans.
(2)    Includes securities with an aggregate fair value of $81 million at December 31, 2024, which were subject to a contractual sale restriction that expired in April 2025.
(3)    The fair value determination of derivatives includes the impact of the credit risk of counterparties to the derivatives and the Company’s own credit risk, the effects of which were not significant.
As of September 30, 2025 and December 31, 2024, Cash and cash equivalents included $17.5 billion and $12.3 billion of cash equivalents, respectively (which would be considered Level 2 in the fair value hierarchy).
Contingent Consideration
Summarized information about the changes in the fair value of liabilities for contingent consideration associated with business combinations is as follows:
($ in millions)20252024
Fair value January 1$193 $354 
Changes in estimated fair value (1)
(52)
Payments (2)
(141)(148)
Fair value September 30
$— $208 
(1)    Recorded in Cost of sales, Research and development expenses, and Other (income) expense, net. Includes cumulative translation adjustments. Amount in 2025 includes the reversal of $45 million for a Zerbaxa sales-based milestone as it was determined that payment was not probable.
(2)    Amount in both periods reflects payments related to the 2016 termination of the Sanofi Pasteur MSD joint venture. Amount in 2025 also includes a $25 million payment related to the achievement of a sales-based milestone for Zerbaxa.
Other Fair Value Measurements
Some of the Company’s financial instruments, such as cash and cash equivalents, receivables and payables, are reflected in the balance sheet at carrying value, which approximates fair value due to their short-term nature.
The estimated fair value of loans payable and long-term debt (including current portion) at September 30, 2025, was $37.7 billion compared with a carrying value of $41.4 billion and at December 31, 2024, was $32.6 billion compared with a carrying value of $37.1 billion. Fair value was estimated using recent observable market prices and would be considered Level 2 in the fair value hierarchy.
Concentrations of Credit Risk
On an ongoing basis, the Company monitors concentrations of credit risk associated with corporate and government issuers of securities and financial institutions with which it conducts business. Credit exposure limits are established to limit a concentration with any single issuer or institution. Cash and investments are placed in instruments that meet high credit quality standards as specified in the Company’s investment policy guidelines.
The majority of the Company’s accounts receivable arise from product sales in the U.S. 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 $1.7 billion and $2.1 billion of accounts receivable as of September 30, 2025 and December 31, 2024, respectively, under these factoring arrangements, which reduced outstanding accounts receivable. The cash received from the financial institutions is reported within operating activities in the Condensed Consolidated Statement of Cash Flows. In certain of these factoring arrangements, for ease of administration, the Company will collect customer payments related to the factored receivables, which it then remits to the financial institutions, generally within thirty days after receipt. As of September 30, 2025 and December 31, 2024, the Company had collected $35 million and $55 million, respectively, on behalf of the financial institutions, which is reflected as restricted cash in Other current assets, and the related obligation to remit the cash is recorded in Accrued and other current liabilities. The net cash flows related to these collections are reported as financing activities in the Condensed Consolidated Statement of Cash Flows. The cost of factoring such accounts receivable was de minimis.
Derivative financial instruments are executed under International Swaps and Derivatives Association master agreements. The master agreements with several of the Company’s financial institution counterparties also include credit support annexes. These annexes contain provisions that require collateral to be exchanged depending on the value of the derivative assets and liabilities, the Company’s credit rating, and the credit rating of the counterparty. Cash collateral received by the Company from various counterparties was $1 million and $165 million at September 30, 2025 and December 31, 2024, respectively. The obligation to return such collateral is recorded in Accrued and other current liabilities.
v3.25.3
Inventories
9 Months Ended
Sep. 30, 2025
Inventory Disclosure [Abstract]  
Inventories Inventories
Inventories consisted of:
($ in millions)September 30, 2025December 31, 2024
Finished goods$2,249 $2,022 
Raw materials and work in process10,165 8,831 
Supplies325 289 
Total12,739 11,142 
Decrease to LIFO cost(883)(840)
 $11,856 $10,302 
Recognized as:
Inventories$6,444 $6,109 
Other Assets5,412 4,193 
Amounts recognized as Other Assets are comprised almost entirely of raw materials and work in process inventories. At September 30, 2025 and December 31, 2024, these amounts included $5.2 billion and $3.8 billion, respectively, of inventories not expected to be sold within one year. In addition, these amounts included $167 million and $412 million at September 30, 2025 and December 31, 2024, respectively, of inventories produced in preparation for product launches.
v3.25.3
Long-Term Debt
9 Months Ended
Sep. 30, 2025
Debt Disclosure [Abstract]  
Long-Term Debt Long-Term Debt
In September 2025, the Company issued $6.0 billion aggregate principal amount of senior unsecured notes consisting of $500 million of floating rate notes due 2027, $750 million of 3.85% notes due 2027, $750 million of 4.15% notes due 2030, $1.0 billion of 4.55% notes due 2032, $1.75 billion of 4.95% notes due 2035, and $1.25 billion of 5.70% notes due 2055. The Company used the net proceeds of the offering for general corporate purposes, including to fund a portion of the approximately $10.5 billion cash consideration and related fees and expenses payable in connection with Merck’s acquisition of Verona Pharma in October 2025 (see Note 2).
v3.25.3
Contingencies
9 Months Ended
Sep. 30, 2025
Commitments and Contingencies Disclosure [Abstract]  
Contingencies Contingencies
The Company is involved in various claims and legal proceedings of a nature considered normal to its business, including product liability, intellectual property, commercial litigation, and securities litigation, as well as certain additional matters including governmental and environmental matters. In the opinion of the Company, it is unlikely that the resolution of these matters will be material to the Company’s financial condition, results of operations or cash flows.
Given the nature of the litigation discussed below and the complexities involved in these matters, the Company is unable to reasonably estimate a possible loss or range of possible loss for such matters until the Company knows, among other factors, (i) what claims, if any, will survive dispositive motion practice, (ii) the extent of the claims, including the size of any potential class, particularly when damages are not specified or are indeterminate, (iii) how the discovery process will affect the litigation, (iv) the settlement posture of the other parties to the litigation and (v) any other factors that may have a material effect on the litigation.
The Company records accruals for contingencies when it is probable that a liability has been incurred and the amount can be reasonably estimated. These accruals are adjusted periodically as assessments change or additional information becomes available. Generally, for product liability claims, a portion of the overall accrual is actuarially determined and considers such factors as past experience, number of claims reported and estimates of claims incurred but not yet reported. Individually significant contingent losses are accrued when probable and reasonably estimable. Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable.
The Company’s decision to obtain insurance coverage is dependent on market conditions, including cost and availability, existing at the time such decisions are made. The Company has evaluated its risks and has determined that the cost of obtaining product liability insurance outweighs the likely benefits of the coverage that is available and, as such, has no insurance for most product liabilities.
Product Liability Litigation
Dr. Scholl’s Foot Powder
As previously disclosed, Merck is a defendant in product liability lawsuits in the U.S. arising from consumers’ alleged exposure to talc in Dr. Scholl’s foot powder, which Merck acquired through its merger with Schering-Plough Corporation and sold as part of the divestiture of Merck’s consumer care business to Bayer in 2014. In these actions, plaintiffs allege that they were exposed to asbestos-contaminated talc and developed mesothelioma as a result. As of September 30, 2025, approximately 605 cases were pending against Merck in various state courts.
Gardasil/Gardasil 9
As previously disclosed, Merck is a defendant in product liability lawsuits in the U.S. involving Gardasil (Human Papillomavirus Quadrivalent [Types 6, 11, 16 and 18] Vaccine, Recombinant) and Gardasil 9 (Human Papillomavirus 9-valent Vaccine, Recombinant). As of September 30, 2025, 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 March 21, 2025, plaintiff’s co-lead counsel in the Gardasil MDL filed a seven-plaintiff complaint in New Jersey state court. On March 24, 2025, Merck removed the case to federal court and requested that the U.S. Judicial Panel on Multidistrict Litigation transfer the case to the Gardasil MDL. Plaintiffs opposed transfer to the Gardasil MDL and moved to have the case remanded to New Jersey state court. On August 7, 2025, the U.S. Judicial Panel on Multidistrict Litigation issued an order transferring the case to the Gardasil MDL.
On May 1, 2025, plaintiff’s co-lead counsel in the Gardasil MDL filed a new six-plaintiff complaint in New Jersey state court. On May 30, 2025, Merck removed the case to federal court and has requested that the U.S. Judicial Panel on Multidistrict Litigation transfer the case to the Gardasil MDL. Plaintiffs have opposed transfer to the Gardasil MDL and have moved to have the case remanded to New Jersey state court.
On July 11, 2025, plaintiff’s co-lead counsel in the Gardasil MDL filed a new six-plaintiff complaint in New Jersey state court. On July 11, 2025, Merck removed the case to federal court and has requested that the U.S. Judicial Panel on Multidistrict Litigation transfer the case to the Gardasil MDL. Plaintiffs have opposed transfer to the Gardasil MDL and have moved to have the case remanded to New Jersey state court.
On January 28, 2025, a trial commenced in California state court. Plaintiff claims that she suffers from POTS and fibromyalgia as a result of her Gardasil vaccinations. On February 14, 2025, after several weeks of trial and an opportunity to litigate plaintiff’s claims before a jury, plaintiff’s counsel approached Merck and proposed that the jury be discharged and the case adjourned. Merck agreed, subject to an explicit stipulation that Merck would provide no financial or other consideration in
exchange for the agreement to adjourn. The case has thus been adjourned until a new trial date of February 2, 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.
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 Demand
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.
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 February 2022 and February 2025. Plaintiff alleges that Merck violated federal securities laws by making materially false and misleading statements and material omissions regarding demand for Gardasil/Gardasil 9 in China. Plaintiff seeks unspecified monetary damages, pre-judgment and post-judgment interest, and fees and costs. On April 7, 2025, the court entered a joint stipulation staying the defendants’ deadline to respond to the complaint until after a lead plaintiff is appointed and requiring the parties to confer and jointly propose deadlines for amending and responding to the complaint within 14 days of the lead plaintiff appointment. Lead plaintiff motions were filed on April 14, 2025, and remain pending.
As previously disclosed, on July 18, 2025, purported Merck stockholder Terence Collins filed a derivative lawsuit in the U.S. District Court for the District of New Jersey, captioned Collins v. Davis, et al., against certain Merck officers and board members. The complaint asserts claims of violation of Section 14(a) of the Securities Act of 1934 (the Exchange Act), breach of fiduciary duty, waste of corporate assets, and unjust enrichment based on the same allegations as in the putative securities class action. On behalf of the Company, the complaint seeks unspecified monetary damages, corporate governance reforms, injunctive relief, restitution, and fees and costs.
On September 2, 2025, purported Merck stockholders Robert Daniel and Daniel Gershen filed a derivative lawsuit in the U.S. District Court for the District of New Jersey, captioned Daniel, et al. v. Frazier, et al., against certain current and former Merck officers and board members for violations of Sections 10(b), 14(a), and 20(a) of the Exchange Act, breach of fiduciary duty, waste of corporate assets, and unjust enrichment based on the same allegations as the putative securities class action and the earlier-filed Collins derivative lawsuit. On behalf of the Company, the complaint seeks unspecified monetary damages, corporate governance reforms, injunctive relief, restitution, and fees and costs.
On September 19, 2025, the parties to the Collins and Daniel lawsuits concurrently filed joint stipulations to stay the lawsuits pending the earliest of the following: (i) dismissal of the securities class action; (ii) any defendant filing an answer in the securities class action; or (iii) any party to the stipulation giving 15 days’ notice that they no longer consent to the stay. The parties also filed joint stipulations to consolidate the Collins and Daniel derivative lawsuits. On October 1, 2025, the district court so-ordered the stay stipulations. The court has not yet taken action in response to the consolidation stipulations.
On September 23, 2025, purported Merck shareholders Gary Weniger, Kathie McGinty, and Pamela Young filed a derivative lawsuit in the Superior Court of New Jersey (Union County), captioned Weniger, et al. v. Frazier, et al., against certain
current and former Merck officers and board members. The complaint asserts claims of breach of fiduciary duty, gross mismanagement, waste of corporate assets, unjust enrichment, insider trading, and a violation of New Jersey securities law based on the same allegations as the putative securities class action and the earlier-filed Collins and Daniel derivative lawsuits. On behalf of the Company, the complaint seeks unspecified monetary damages, disgorgement of any illicitly gained proceeds, corporate governance reforms, injunctive relief, restitution, and fees and costs.
Commercial and Other Litigation
Zetia Antitrust Litigation
As previously disclosed, Merck, MSD, Schering Corporation, Schering-Plough Corporation, and MSP Singapore Company LLC (collectively, the Merck Defendants) were defendants in a number of lawsuits filed in 2018 on behalf of direct and indirect purchasers of Zetia (ezetimibe) alleging violations of federal and state antitrust laws, as well as other state statutory and common law causes of action. The cases were consolidated in a federal multidistrict litigation (Zetia MDL) before Judge Rebecca Beach Smith in the Eastern District of Virginia. In April 2023, the Merck Defendants reached settlements with the direct purchaser and retailer plaintiffs, and a settlement with the indirect purchaser class that the court approved in October 2023.
As previously disclosed, in 2020 and 2021, United HealthCare Services, Inc. (United HealthCare), Humana Inc. (Humana), Centene Corporation and others (Centene), and Kaiser Foundation Health Plan, Inc. (Kaiser) (collectively, the Insurer Plaintiffs), each filed a lawsuit in a jurisdiction outside of the Eastern District of Virginia against the Merck Defendants and others, making similar allegations as those made in the Zetia MDL, as well as additional allegations about Vytorin. These cases were transferred to the Eastern District of Virginia to proceed with the Zetia MDL.
In December 2023, the U.S. Judicial Panel on Multidistrict Litigation remanded the four Insurer Plaintiff cases to the transferor courts in the Northern District of California (Kaiser), the District of Minnesota (United HealthCare), and the District of New Jersey (Humana and Centene). The Merck Defendants filed motions to dismiss in each of the Insurer Plaintiff cases.
In December 2024, the district court in the District of New Jersey granted in part and denied in part the motions to dismiss in the Humana and Centene cases and, on January 29, 2025, Humana and Centene filed amended complaints. On March 5, 2025, the Merck Defendants filed motions to dismiss the amended complaints. On March 24, 2025, the Merck Defendants filed a third-party complaint against AmerisourceBergen Drug Corp., AmerisourceBergen Corp., and Cencora, Inc., (collectively, Cencora) seeking indemnification and a declaration of rights for Humana’s direct purchaser claims. On June 23, 2025, Cencora moved to dismiss the third-party complaint or, in the alternative, to transfer the third-party action to the Eastern District of Virginia.
On February 25, 2025, the district court in the District of Minnesota granted in part and denied in part the motion to dismiss in the United HealthCare case. On March 11, 2025, the Merck Defendants filed an answer and affirmative defenses in response to United HealthCare’s complaint. On March 24, 2025, the Merck Defendants filed a third-party complaint against Cardinal Health, Inc., Cardinal Health 110, LLC, and Cardinal Health 112, LLC (collectively, Cardinal), seeking indemnification and a declaration of rights for certain of United HealthCare’s direct and indirect purchaser claims. On June 6, 2025, Cardinal filed a motion to dismiss the Merck Defendants’ third-party complaint on forum grounds, or in the alternative, to stay the Merck Defendants’ third-party claims pending arbitration.
On March 18, 2025, the district court in the Northern District of California granted in part and denied in part the motion to dismiss in the Kaiser case. The court granted Kaiser leave to amend its complaint, and Kaiser filed its second amended complaint on April 15, 2025. On May 20, 2025, the Merck Defendants moved to dismiss certain claims in the second amended complaint.
Qui Tam Litigation
As previously disclosed, in June 2012, the U.S. District Court for the Eastern District of Pennsylvania unsealed a complaint that had been filed against the Company under the federal False Claims Act by two former employees alleging, among other things, that the Company defrauded the U.S. government by falsifying data in connection with a clinical study conducted on the mumps component of the Company’s M-M-R II vaccine. The complaint alleged the fraud took place between 1999 and 2001. The U.S. government had the right to participate in and take over the prosecution of this lawsuit but notified the court that it declined to exercise that right. The two former employees pursued the lawsuit without the involvement of the U.S. government. In July 2023, the court denied relators’ motion for summary judgment, granted two of the Company’s motions for summary judgment, and denied the Company’s remaining motions for summary judgment as moot. The court entered judgment in favor of the Company and dismissed relators’ amended complaint in full with prejudice. Relators appealed that decision, and in August 2024, the Third Circuit affirmed the district court’s decision.
In addition, as previously disclosed, two putative class action lawsuits on behalf of direct purchasers of the M‑M‑R II vaccine, which charge that the Company misrepresented the efficacy of the M-M-R II vaccine in violation of federal antitrust laws and various state consumer protection laws, are pending in the Eastern District of Pennsylvania. The court granted the Company’s motion for summary judgment as to plaintiffs’ state law claims and denied the motion as to plaintiffs’ antitrust claim. The Company appealed and, in October 2024, the Third Circuit reversed-in-part the district court’s order and remanded the case with instructions to enter summary judgment for the Company. In November 2024, plaintiffs-appellees filed a petition for rehearing and rehearing en banc and, on February 10, 2025, the court denied the petition. On October 20, 2025, the Supreme Court denied the plaintiffs’ certiorari petition, ending the matter.
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 FDA seeking to market generic and biosimilar forms of the Company’s products prior to the expiration of relevant patents owned by the Company. To protect its patent rights, the Company may file patent infringement lawsuits against such generic and biosimilar companies. Similar lawsuits defending the Company’s patent rights may exist in other countries. The Company intends to vigorously defend its patents, which it believes are valid, against infringement by companies attempting to market products prior to the expiration of such patents. As with any litigation, there can be no assurance of the outcomes, which, if adverse, could result in significantly shortened periods of exclusivity for these products and, with respect to products acquired through acquisitions accounted for as business combinations, potentially significant intangible asset impairment charges. In addition to these matters, the Company may be involved in other litigation involving its intellectual property and intellectual property owned or licensed by other companies.
Bridion As previously disclosed, between January and November 2020, the Company received multiple Paragraph IV Certification Letters under the Hatch-Waxman Act notifying the Company that generic drug companies had filed applications to the FDA seeking pre-patent expiry approval to sell generic versions of Bridion (sugammadex) Injection. In March, April and December 2020, the Company filed patent infringement lawsuits in the U.S. District Courts for the District of New Jersey and the Northern District of West Virginia against those generic companies. All actions in the District of New Jersey were consolidated. The West Virginia case was jointly dismissed with prejudice in August 2022 in favor of proceeding in New Jersey. The remaining defendants in the New Jersey action stipulated to infringement of the asserted claims and withdrew all remaining claims and defenses other than a defense seeking to shorten the patent term extension (PTE) of the sugammadex patent to December 2022. The U.S. District Court for the District of New Jersey held a one-day trial in December 2022 on this remaining PTE calculation defense.
In June 2023, the U.S. District Court for the District of New Jersey ruled in Merck’s favor. The court held that Merck’s calculation of PTE for the sugammadex patent covering the compound is not invalid and that the U.S. Patent & Trademark Office correctly granted a full five-year extension. Also in June 2023, the U.S. District Court for the District of New Jersey issued a final judgment prohibiting the FDA from approving any of the pending or tentatively approved generic applications until January 27, 2026, except for any subsequent agreements between defendants and Merck or further order by the court. In July 2023, the defendants filed a notice of appeal with the U.S. Court of Appeals for the Federal Circuit. Oral argument took place on February 4, 2025. On March 13, 2025, the Federal Circuit affirmed the district court’s decision, holding that the patent term extension granted to the sugammadex patent covering Bridion was not invalid and that the patent is entitled to its full five-year patent term extension. The FDA has now granted Bridion six months of pediatric exclusivity.
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) or earlier under certain circumstances. The FDA has now granted Bridion six months of pediatric exclusivity. 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 or earlier under certain circumstances, and their generic versions of Janumet XR to the market in July 2026 or earlier under certain circumstances.
In March 2021, the Company filed a patent infringement lawsuit in the U.S. District Court for the District of Delaware against Zydus Worldwide DMCC, Zydus Pharmaceuticals (USA) Inc., and Cadila Healthcare Ltd. (collectively, Zydus). In that lawsuit, the Company alleged infringement of the salt/polymorph patent based on the filing of Zydus’s NDA seeking approval of a form of sitagliptin that is different from than that used in Januvia. In December 2022, the parties reached settlement that included dismissal of the case without prejudice enabling Zydus to seek final approval of a non-automatically substitutable product. In January 2023, the Company received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying the Company that Zydus filed an ANDA seeking approval of sitagliptin/metformin HCl tablets. In March 2023, the parties reached settlement enabling Zydus to seek final approval of a non-automatically substitutable product containing a different form of sitagliptin than that used in Janumet. In November 2023, the Company received a Paragraph IV Certification Letter under the Hatch-Waxman Act notifying the Company that Zydus filed an ANDA seeking approval of sitagliptin/metformin HCl Extended Release tablets. In January 2024, the parties reached settlement enabling Zydus to seek final approval of a non-automatically substitutable version containing a different form of sitagliptin than that used in Janumet XR.
As a result of these settlement agreements related to the later expiring 2027 salt/polymorph patent directed to the specific sitagliptin salt form of the products, the Company expects that Januvia and Janumet will not lose market exclusivity in
the U.S. until May 2026 and Janumet XR will not lose market exclusivity in the U.S. until July 2026, although Zydus has received FDA approval for a non-automatically substitutable form of sitagliptin that differs from the form in the Company’s sitagliptin products.
In March 2024, the Company received another Paragraph IV Certification Letter under the Hatch-Waxman Act from Azurity Pharmaceuticals, Inc. (Azurity) asserting that a different sitagliptin product subject to its ANDA does not infringe the salt/polymorph patent. In May 2024, Merck filed a civil action in the U.S. District Court of Delaware alleging infringement. The case was dismissed without prejudice in July 2024. Following the dismissal, the Company granted Azurity a covenant not to assert the salt/polymorph patent against the Azurity product that is the subject of such ANDA.
Supplementary Protection Certificates (SPCs) for Janumet expired in April 2023 for the majority of European countries. Prior to expiration, generic companies sought revocation of the Janumet SPCs in a number of European countries. In February 2022, a Finnish court referred certain questions to the Court of Justice of the European Union that could impact the validity of the Janumet SPCs in Europe. A decision rendered in December 2024 provides guidance on points of law and does not directly apply to the Janumet SPCs. Thus, additional proceedings in certain countries where generic companies were prevented from launching products during the SPC period may be necessary to determine whether the SPCs are valid and if not, whether damages are appropriate. Those countries include Belgium, Czech Republic, 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. and Medisa Shinyaku Co., Ltd (collectively, Defendants) in the Tokyo District Court seeking an injunction to stop the manufacture, sale and offer for sale of the Defendants’ sitagliptin dihydrogen phosphate product, while the Company’s patents and patent term extensions are in force. The lawsuit is in response to the Defendants’ application for marketing authorization to sell a generic sitagliptin dihydrogen phosphate product, in the anhydrate form, which was approved in August 2023. Merck asserts that the Defendants’ activity infringes a patent term extension associated with Merck’s patent directed to the sitagliptin compound patent.
Keytruda As previously disclosed, in November 2022, the Company filed a complaint against The Johns Hopkins University (JHU) in the U.S. District Court of Maryland. This action concerns a joint research collaboration between Merck and JHU regarding the use of Keytruda in certain indications. Merck and JHU partnered to design and conduct a clinical study administering Keytruda to cancer patients having tumors that had the genetic biomarker known as microsatellite instability-high (MSI-H) (the Joint Clinical Study). Subsequently JHU obtained a number of U.S. patents specifically relying on the Joint Clinical Study. Merck alleges that JHU breached the collaboration agreement by obtaining issuance of these patents without informing or involving Merck, which were licensed to others, and then trying to enforce these patents against Merck. Merck therefore brought an action for breach of contract, declaratory judgment of noninfringement, and promissory estoppel. JHU answered the complaint in April and May 2023, denying Merck’s claims, and counterclaiming for willful infringement of nine issued U.S. patents, including a demand for damages. Between November 30, 2023, and March 13, 2024, the Company filed inter partes review petitions with the United States Patent Office’s Patent Trial and Appeal Board (PTAB), challenging the patentability of all nine patents asserted in the district court. Between June 2024 and October 2024, the PTAB instituted a review of all nine challenged patents. In June 2024, the district court granted Merck’s motion to stay the case in its entirety pending the outcome of the PTAB proceeding instituted in June 2024.
Between June and October of 2025, the PTAB issued Final Written Decisions finding all claims of the first six patents challenged unpatentable. JHU has filed notices of appeal to the Federal Circuit Court of Appeals for two of the patents invalidated by the PTAB. Director Review Requests and/or Appeals are still possible for the four additional patents invalidated by the PTAB. The remaining three patents are expected to have Final Written Decisions issued by the PTAB in mid to late November 2025. The district court’s stay is expected to continue until at least the issuance of Final Written Decisions for the three remaining patents.
Subcutaneous Pembrolizumab Halozyme, Inc. 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. On June 2, 2025, the PTAB instituted the first petition filed by the Company. Since then, the PTAB also instituted ten additional petitions. Institution decisions on three additional patents in the MDASE portfolio are still pending.
On April 24, 2025, Halozyme, Inc. filed a complaint in the U.S. District Court for the District of New Jersey alleging that the Company’s activities related to subcutaneous pembrolizumab infringe or will infringe 15 patents belonging to the MDASE portfolio, 12 of which are the subject of the Company’s already filed PGR petitions. Although there are three patents that were not and cannot be challenged using the PGR process, the Company believes those patents are invalid and suffer from the same defects as the patents currently being challenged and those patents can be challenged in court proceedings if required.
Between August and September 2025, the Company filed revocation actions against EP Patent No. 2 797 622 (the ‘622 patent) owned by Halozyme, Inc. in the UK, France, Germany and The Netherlands. Halozyme, Inc. 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. On October 2, 2025, the Company accepted service of a preliminary injunction filed by Halozyme, Inc. under the ‘622 patent in Germany. A preliminary injunction hearing is scheduled to occur on December 4, 2025.
Lynparza As previously disclosed, between December 2022 and November 2024, AstraZeneca Pharmaceuticals LP received Paragraph IV Certification Letters under the Hatch-Waxman Act notifying AstraZeneca that Natco Pharma Limited, Sandoz Inc., Cipla USA, Inc and Cipla Limited (collectively Cipla), and Zydus Pharmaceuticals (USA) Inc. have filed separate applications to the FDA seeking pre-patent expiry approval to sell generic versions of Lynparza (olaparib) tablet. Between February 2023 and January 2025, AstraZeneca and the Company filed a series of patent infringement lawsuits in the U.S. District Court for the District of New Jersey against each generic company asserting a number of Orange-Book listed patents. The filing of the initial infringement suit generally stays FDA approval for 30 months from the date of the Paragraph IV notice or until an adverse court decision, if any, whichever may occur earlier. In these cases, however, none of the generic companies are challenging the patent specifically claiming the olaparib compound which expires in September 2027. Thus, the earliest date the FDA can approve any of the currently pending generic applications is September 2027. All cases have been consolidated and a trial is expected in 2026.
Capvaxive On September 5, 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. 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.
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 September 30, 2025 and December 31, 2024 of approximately $220 million and $225 million, respectively, represents the Company’s best estimate of the minimum amount of defense costs to be incurred in connection with its outstanding litigation; however, events such as additional trials and other events that could arise in the course of its litigation could affect the ultimate amount of legal defense costs to be incurred by the Company. The Company will continue to monitor its legal defense costs and review the adequacy of the associated reserves and may determine to increase the reserves at any time in the future if, based upon the factors set forth, it believes it would be appropriate to do so.
v3.25.3
Equity
9 Months Ended
Sep. 30, 2025
Equity [Abstract]  
Equity Equity
Three Months Ended September 30,
   Common StockOther
Paid-In
Capital
Retained
Earnings
Accumulated
Other
Comprehensive
Loss
 Treasury StockNon-
controlling
Interests
Total
($ and shares in millions except per share amounts)SharesPar ValueSharesCost
Balance at July 1, 2024
3,577 $1,788 $44,362 $60,187 $(5,361)1,041 $(57,394)$66 $43,648 
Net income attributable to Merck & Co., Inc.
— — — 3,157 — — — — 3,157 
Other comprehensive loss, net of taxes— — — — (10)— — — (10)
Cash dividends declared on common stock ($0.77 per share)
— — — (1,960)— — — — (1,960)
Treasury stock shares purchased— — — — — (444)— (444)
Share-based compensation plans and other— — 168 — — — — 177 
Net income attributable to noncontrolling interests— — — — — — — 
Distributions attributable to noncontrolling interests— — — — — — — (12)(12)
Balance at September 30, 20243,577 $1,788 $44,530 $61,384 $(5,371)1,045 $(57,829)$58 $44,560 
Balance at July 1, 2025
3,577 $1,788 $44,644 $68,477 $(5,421)1,074 $(60,495)$67 $49,060 
Net income attributable to Merck & Co., Inc.— — — 5,785 — — — — 5,785 
Other comprehensive income, net of taxes
— — — — 219 — — — 219 
Cash dividends declared on common stock ($0.81 per share)
— — — (2,031)— — — — (2,031)
Treasury stock shares purchased— — — — — 16 (1,324)— (1,324)
Share-based compensation plans and other— — 188 — — — 20 — 208 
Net income attributable to noncontrolling interests— — — — — — — 
Distributions attributable to noncontrolling interests— — — — — — — (12)(12)
Balance at September 30, 20253,577 $1,788 $44,832 $72,231 $(5,202)1,090 $(61,799)$57 $51,907 
Nine Months Ended September 30,
   Common StockOther
Paid-In
Capital
Retained
Earnings
Accumulated
Other
Comprehensive
Loss
 Treasury StockNon-
controlling
Interests
Total
($ and shares in millions except per share amounts)SharesPar ValueSharesCost
Balance at January 1, 2024
3,577 $1,788 $44,509 $53,895 $(5,161)1,045 $(57,450)$54 $37,635 
Net income attributable to Merck & Co., Inc.
— — — 13,374 — — — — 13,374 
Other comprehensive loss, net of taxes— — — — (210)— — — (210)
Cash dividends declared on common stock ($2.31 per share)
— — — (5,885)— — — — (5,885)
Treasury stock shares purchased— — — — — (817)— (817)
Share-based compensation plans and other— — 21 — — (7)438 460 
Net income attributable to noncontrolling interests— — — — — — — 15 15 
Distributions attributable to noncontrolling interests— — — — — — — (12)(12)
Balance at September 30, 20243,577 $1,788 $44,530 $61,384 $(5,371)1,045 $(57,829)$58 $44,560 
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.— — — 15,291 — — — — 15,291 
Other comprehensive loss, net of taxes— — — — (257)— — — (257)
Cash dividends declared on common stock ($2.43 per share)
— — — (6,129)— — — — (6,129)
Treasury stock shares purchased— — — — — 46 (3,832)— (3,832)
Share-based compensation plans and other— — 128 — — (5)336 — 464 
Net income attributable to noncontrolling interests— — — — — — — 10 10 
Distributions attributable to noncontrolling interests— — — — — — — (12)(12)
Balance at September 30, 20253,577 $1,788 $44,832 $72,231 $(5,202)1,090 $(61,799)$57 $51,907 
v3.25.3
Pension and Other Postretirement Benefit Plans
9 Months Ended
Sep. 30, 2025
Retirement Benefits [Abstract]  
Pension and Other Postretirement Benefit Plans Pension and Other Postretirement Benefit Plans
The Company has defined benefit pension plans covering eligible employees in the U.S. and in certain of its international subsidiaries. The net periodic benefit cost (credit) of such plans consisted of the following components: 
Three Months Ended
September 30,
Nine Months Ended
September 30,
2025202420252024
($ in millions)U.S.InternationalU.S.InternationalU.S.InternationalU.S.International
Service cost$100 $57 $100 $60 $279 $171 $273 $182 
Interest cost143 78 134 74 425 225 403 220 
Expected return on plan assets(210)(159)(206)(139)(630)(454)(621)(416)
Amortization of unrecognized prior service credit
— (4)— (3)— (12)— (10)
Net loss amortization
16 12 42 30 
Termination benefits— — — — — 
Curtailments(16)— — (16)— — 
 $58 $(41)$41 $(7)$125 $(78)$90 $(20)
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
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Service cost$$$29 $23 
Interest cost15 14 46 42 
Expected return on plan assets(13)(20)(39)(60)
Amortization of unrecognized prior service credit(10)(11)(30)(32)
Net gain amortization(12)(14)(33)(38)
 $(11)$(24)$(27)$(65)
In connection with restructuring actions (see Note 4), termination charges were recorded on pension plans related to expanded eligibility for certain employees exiting Merck. Also, in connection with these restructuring activities, curtailments were recorded on certain pension plans.
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.
v3.25.3
Other (Income) Expense, Net
9 Months Ended
Sep. 30, 2025
Other Income and Expenses [Abstract]  
Other (Income) Expense, Net Other (Income) Expense, Net
Other (income) expense, net, consisted of: 
 Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Interest income$(96)$(127)$(274)$(269)
Interest expense327 330 946 943 
Exchange losses56 33 224 177 
(Income) loss from investments in equity securities, net (1)
(373)31 (563)(169)
Net periodic defined benefit plan (credit) cost other than service cost(152)(157)(452)(476)
Other, net— (272)(162)(357)
 $(238)$(162)$(281)$(151)
(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.
Other, net (as reflected in the table above) in the third quarter and first nine months of 2024 includes $170 million of income related to the expansion of the existing development and commercialization agreement with Daiichi Sankyo (see Note 3).
Interest paid for the nine months ended September 30, 2025 and 2024 was $849 million and $822 million, respectively.
v3.25.3
Income Taxes
9 Months Ended
Sep. 30, 2025
Income Tax Disclosure [Abstract]  
Income Taxes Income Taxes
The effective income tax rates of 14.2% and 13.3% for the third quarter and first nine months of 2025, respectively, reflect the favorable impacts of geographical mix of income and expense, as well as certain discrete items.
The effective income tax rate of 22.7% for the third quarter of 2024 reflects a 7.2 percentage point combined unfavorable impact of charges related to the acquisitions of EyeBio and MK-1045, which had minimal tax benefits. The effective income tax rate of 15.1% for the first nine months of 2024 reflects a 2.1 percentage point combined unfavorable impact of charges related to the acquisitions of Harpoon, EyeBio and MK-1045, which had minimal tax benefits. The effective income tax rate for the first nine months of 2024 also reflects a 1.6 percentage point favorable impact due to a $259 million reduction in reserves for unrecognized income tax benefits resulting from the expiration in June 2024 of the statute of limitations for assessments related to the 2019 federal tax return year.
While many jurisdictions in which Merck operates have adopted the global minimum tax provision of the Organization for Economic Cooperation and Development (OECD) Pillar 2, effective for tax years beginning in January 2024, it resulted in a minimal impact to the Company’s 2024 effective income tax rate due to the accounting for the tax effects of intercompany transactions. In addition, in July 2025, H.R.1 - One Big Beautiful Bill Act (OBBBA) was enacted into law, which had an immaterial impact to the effective tax rates for the third quarter and first nine months of 2025.
The Internal Revenue Service (IRS) is currently conducting examinations of the Company’s tax returns for the years 2017 and 2018, including the one-time transition tax enacted under the Tax Cuts and Jobs Act of 2017 (TCJA). In April 2025, Merck received Notices of Proposed Adjustment (NOPAs) that would increase the amount of the one-time transition tax on certain undistributed earnings of foreign subsidiaries by approximately $1.3 billion. In addition, the NOPAs included penalties of approximately $260 million. These amounts are exclusive of any interest that may be due. The Company disagrees with the proposed adjustments and will vigorously contest the NOPAs through all available administrative and, if necessary, judicial proceedings. It is expected to take a number of years to reach resolution of this matter. If the Company is ultimately unsuccessful in defending its position, the impact could be material to its financial statements. The statute of limitations for assessments with respect to the 2019 and 2020 federal tax return years expired in June 2024 (as noted above) and October 2024, respectively. The IRS is also currently conducting examinations of the Company’s tax returns for the years 2021 and 2022. In addition, various state and foreign examinations are in progress.
v3.25.3
Earnings Per Share
9 Months Ended
Sep. 30, 2025
Earnings Per Share [Abstract]  
Earnings Per Share Earnings Per Share
The calculations of earnings per share are as follows:
 Three Months Ended
September 30,
Nine Months Ended
September 30,
($ and shares in millions except per share amounts)2025202420252024
Net Income Attributable to Merck & Co., Inc.
$5,785 $3,157 $15,291 $13,374 
Average common shares outstanding2,495 2,534 2,509 2,534 
Common shares issuable (1)
Average common shares outstanding assuming dilution 2,498 2,541 2,514 2,543 
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders
$2.32 $1.25 $6.09 $5.28 
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders
$2.32 $1.24 $6.08 $5.26 
(1)    Issuable primarily under share-based compensation plans.
For the third quarter of 2025 and 2024, 15 million and 7 million, respectively, and for the first nine months of 2025 and 2024, 12 million and 6 million, respectively, of common shares issuable under share-based compensation plans were excluded from the computations of earnings per common share assuming dilution because the effect would have been antidilutive.
v3.25.3
Other Comprehensive Income (Loss)
9 Months Ended
Sep. 30, 2025
Equity [Abstract]  
Other Comprehensive Income (Loss) Other Comprehensive Income (Loss)
Changes in each component of other comprehensive income (loss) are as follows:
Three Months Ended September 30,
($ in millions)DerivativesEmployee
Benefit
Plans
Foreign Currency
Translation
Adjustment
Accumulated Other
Comprehensive
Loss
Balance July 1, 2024, net of taxes
$173 $(2,808)$(2,726)$(5,361)
Other comprehensive income (loss) before reclassification adjustments, pretax(325)— 279 (46)
Tax68 (3)20 85 
Other comprehensive income (loss) before reclassification adjustments, net of taxes(257)(3)299 39 
Reclassification adjustments, pretax(49)
(1)
(14)
(2)
— (63)
Tax10 — 14 
Reclassification adjustments, net of taxes(39)

(10)

— (49)
Other comprehensive income (loss), net of taxes(296)(13)299 (10)
Balance September 30, 2024, net of taxes
$(123)$(2,821)$(2,427)$(5,371)
Balance July 1, 2025, net of taxes
$(385)$(2,353)$(2,683)$(5,421)
Other comprehensive income (loss) before reclassification adjustments, pretax113 93 (64)142 
Tax(24)39 16 
Other comprehensive income (loss) before reclassification adjustments, net of taxes89 94 (25)158 
Reclassification adjustments, pretax103 
(1)
(22)
(2)
— 81 
Tax(22)— (20)
Reclassification adjustments, net of taxes81 

(20)

— 61 
Other comprehensive income (loss), net of taxes170 74 (25)219 
Balance September 30, 2025, net of taxes
$(215)$(2,279)$(2,708)$(5,202)

Nine Months Ended September 30,
($ in millions)DerivativesEmployee
Benefit
Plans
Foreign Currency
Translation
Adjustment
Accumulated Other
Comprehensive
Loss
Balance January 1, 2024, net of taxes
$(24)$(2,793)$(2,344)$(5,161)
Other comprehensive income (loss) before reclassification adjustments, pretax22 (103)(75)
Tax(5)(5)— (10)
Other comprehensive income (loss) before reclassification adjustments, net of taxes17 (103)(85)
Reclassification adjustments, pretax(147)
(1)
(44)
(2)
20 (171)
Tax31 15 — 46 
Reclassification adjustments, net of taxes(116)(29)20 (125)
Other comprehensive income (loss), net of taxes(99)(28)(83)(210)
Balance September 30, 2024, net of taxes
$(123)$(2,821)$(2,427)$(5,371)
Balance January 1, 2025, net of taxes
$242 $(2,327)$(2,860)$(4,945)
Other comprehensive income (loss) before reclassification adjustments, pretax(630)91 270 (269)
Tax132 — (118)14 
Other comprehensive income (loss) before reclassification adjustments, net of taxes(498)91 152 (255)
Reclassification adjustments, pretax52 
(1)
(40)
(2)
— 12 
Tax(11)(3)— (14)
Reclassification adjustments, net of taxes41 (43)— (2)
Other comprehensive income (loss), net of taxes(457)48 152 (257)
Balance September 30, 2025, net of taxes
$(215)$(2,279)$(2,708)$(5,202)
(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).
v3.25.3
Segment Reporting
9 Months Ended
Sep. 30, 2025
Segment Reporting [Abstract]  
Segment Reporting Segment Reporting
The Company’s operations are principally managed on a product basis and include two operating segments, Pharmaceutical and Animal Health, both of which are reportable segments.
The Pharmaceutical segment includes human health pharmaceutical and vaccine products. Human health pharmaceutical products consist of therapeutic and preventive agents, generally sold by prescription, for the treatment of human disorders. The Company sells these human health pharmaceutical products primarily to drug wholesalers and retailers, hospitals, government agencies and managed health care providers such as health maintenance organizations, pharmacy benefit managers and other institutions. Human health vaccine products consist of preventive pediatric, adolescent and adult vaccines. The Company sells these human health vaccines primarily to physicians, wholesalers, distributors and government entities. A large component of pediatric and adolescent vaccine sales are made to the U.S. Centers for Disease Control and Prevention Vaccines for Children program, which is funded by the U.S. government. Additionally, the Company sells vaccines to the Federal government for placement into vaccine stockpiles.
The Animal Health segment discovers, develops, manufactures and markets a wide range of veterinary pharmaceutical and vaccine products, as well as health management solutions and services, for the prevention, treatment and control of disease in all major livestock and companion animal species. The Company also offers an extensive suite of digitally connected identification, traceability and monitoring products. The Company sells its products to veterinarians, distributors, animal producers, farmers and pet owners.
Sales of the Company’s products were as follows:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
 ($ in millions)U.S.Int’lTotalU.S.Int’lTotalU.S.Int’lTotalU.S.Int’lTotal
Pharmaceutical:
Oncology
Keytruda$4,879 $3,263 $8,142 $4,500 $2,929 $7,429 $13,936 $9,367 $23,303 $13,031 $8,614 $21,646 
Alliance revenue-Lynparza (1)
184 195 379 161 177 337 503 558 1,061 449 498 947 
Alliance revenue-Lenvima (1)
177 81 258 173 78 251 545 236 781 523 233 755 
Welireg161 35 196 127 12 139 422 74 496 320 29 349 
Alliance revenue-Reblozyl (2)
111 25 136 82 18 100 299 62 361 215 45 261 
Vaccines
Gardasil/Gardasil 9
1,154 595 1,749 1,020 1,285 2,306 2,235 1,967 4,202 2,045 4,988 7,032 
ProQuad/M-M-R II/Varivax
554 130 684 572 131 703 1,457 374 1,832 1,500 391 1,891 
Vaxneuvance134 91 226 137 103 239 409 276 685 397 251 647 
RotaTeq141 63 204 131 62 193 366 187 554 388 185 572 
Capvaxive
238 244 47 — 47 473 480 47 — 47 
Pneumovax 23
10 35 45 19 49 68 13 111 124 36 152 188 
Hospital Acute Care
Bridion392 47 439 339 81 420 1,181 161 1,341 1,020 296 1,315 
Prevymis128 138 266 101 107 208 345 357 702 265 305 570 
Zerbaxa49 32 81 39 26 64 136 89 225 106 77 182 
Dificid30 13 43 83 13 96 185 37 222 231 30 261 
Cardiovascular
Winrevair
335 25 360 147 149 926 49 976 216 219 
Alliance revenue-Adempas/Verquvo (3)
103 112 96 102 308 32 340 283 22 306 
Adempas— 82 82 — 72 72 — 229 229 — 214 214 
Virology
Lagevrio24 114 138 84 299 383 90 233 323 144 699 843 
Isentress/Isentress HD
44 37 82 54 48 102 144 114 258 147 155 302 
Delstrigo
13 64 77 15 50 65 42 185 228 42 139 180 
Pifeltro
29 14 43 31 12 42 86 43 128 86 37 123 
Neuroscience
Belsomra28 19 47 20 58 78 59 77 137 53 124 177 
Immunology
Simponi— — — — 189 189 — — — — 545 545 
Remicade— — — — 41 41 — — — — 115 115 
Diabetes
Januvia258 124 382 67 211 278 819 483 1,302 428 674 1,102 
Janumet78 165 243 15 190 204 210 530 741 70 610 679 
Other pharmaceutical (4)
239 716 953 167 466 638 558 1,713 2,268 521 1,364 1,890 
Total Pharmaceutical segment sales9,493 6,118 15,611 8,227 6,717 14,943 25,747 17,552 43,299 22,563 20,795 43,358 
Animal Health:
Livestock213 811 1,023 194 692 886 598 2,312 2,909 529 2,044 2,573 
Companion Animal291 301 592 293 307 601 907 1,033 1,940 888 1,019 1,907 
Total Animal Health segment sales504 1,112 1,615 487 999 1,487 1,505 3,345 4,849 1,417 3,063 4,480 
Total segment sales9,997 7,230 17,226 8,714 7,716 16,430 27,252 20,897 48,148 23,980 23,858 47,838 
Other (5)
15 34 50 22 206 227 119 343 463 109 597 706 
 $10,012 $7,264 $17,276 $8,736 $7,922 $16,657 $27,371 $21,240 $48,611 $24,089 $24,455 $48,544 
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 $214 million and $39 million in the third quarter of 2025 and 2024, respectively, and $301 million and $114 million in the first nine months of 2025 and 2024, respectively (see Note 3).
(5)    Other is primarily comprised of miscellaneous corporate revenue, including revenue hedging activities which (decreased) increased sales by $(61) million and $156 million for the nine months ended September 30, 2025 and 2024, respectively, as well as revenue from third-party manufacturing arrangements (including sales to Organon & Co.). Other for the nine months ended September 30, 2025 and 2024 also includes $111 million and $91 million, respectively, related to upfront and milestone payments received by Merck for out-licensing arrangements.
Product sales are recorded net of the provision for discounts, including chargebacks, which are customer discounts that occur when a contracted customer purchases through an intermediary wholesale purchaser, and rebates that are owed based upon definitive contractual agreements or legal requirements with private sector and public sector (Medicaid and Medicare Part D) benefit providers, after the final dispensing of the product by a pharmacy to a benefit plan participant. These discounts, in the aggregate, reduced U.S. sales by $2.6 billion and $3.6 billion for the three months ended September 30, 2025 and 2024, respectively, and $7.2 billion and $10.1 billion for the nine months ended September 30, 2025 and 2024, respectively.
Consolidated sales by geographic area where derived are as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
United States$10,012 $8,736 $27,371 $24,089 
Europe, Middle East and Africa3,680 3,583 10,789 10,661 
Latin America905 936 2,556 2,591 
Asia Pacific (other than China and Japan)764 823 2,238 2,294 
Japan712 938 2,007 2,445 
China405 1,017 1,553 4,606 
Other798 624 2,097 1,858 
 $17,276 $16,657 $48,611 $48,544 
A reconciliation of segment profits to Income Before Taxes is as follows:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
TotalPharma-ceutical
Animal
Health
TotalPharma-ceutical
Animal
Health
Total
Segment sales$15,611 $1,615 $17,226 $14,943 $1,487 $16,430 $43,299 $4,849 $48,148 $43,358 $4,480 $47,838 
Less segment costs: (1)
Cost of sales1,664 710 1,904 613 4,838 1,968 5,319 1,838 
Selling, general and administrative1,469 277 1,519 268 4,327 822 4,462 791 
Research and development (2)
— 118 — 95 — 323 — 276 
Other segment items (3)
(60)(1)(27)(130)(1)(74)
Total segment profits$12,538 $511 $13,049 $11,547 $510 $12,057 $34,264 $1,737 $36,001 $33,651 $1,574 $35,225 
Other profits117 235 391 
Unallocated:
Interest income96 127 274 269 
Interest expense(327)(330)(946)(943)
Amortization(623)(633)(1,820)(1,720)
Depreciation(449)(467)(1,345)(1,368)
Research and development(3,839)(5,716)(11,159)(12,926)
Restructuring costs(47)(56)(676)(258)
Other unallocated, net(1,119)(1,009)(2,917)(2,904)
$6,745 $4,090 $17,647 $15,766 
(1)    The significant expense categories and amounts align with the segment level information that is regularly provided to the chief operating decision maker.
(2)    Human health-related research and development expenses incurred by Merck Research Laboratories are not allocated to segment profits as noted below.
(3)    Includes equity (income) loss from affiliates and other miscellaneous non-operating expenses.
Pharmaceutical segment profits are comprised of segment sales less standard costs, as well as selling, general and administrative expenses directly incurred by the segment. Animal Health segment profits are comprised of segment sales, less all cost of sales, as well as selling, general and administrative expenses and research and development costs directly incurred by the segment. The chief operating decision maker (Merck’s Chief Executive Officer) uses segment profit to allocate resources predominately during the planning and forecasting process. For internal management reporting presented to the chief operating decision maker, Merck does not allocate the remaining cost of sales not included in segment profits as described above, research and development expenses incurred by Merck Research Laboratories (the Company’s research and development division that focuses on human health-related activities), or general and administrative expenses not directly incurred by the segments, nor the cost of financing these activities. Separate divisions maintain responsibility for monitoring and managing these costs, including depreciation related to fixed assets utilized by these divisions and, therefore, they are not included in segment profits. In addition, costs related to restructuring activities, as well as the amortization of intangible assets and amortization of purchase accounting adjustments are not allocated to segments.
Other profits are primarily comprised of miscellaneous corporate profits, as well as operating profits (losses) related to third-party manufacturing arrangements.
Other unallocated, net, includes expenses from corporate and manufacturing cost centers, intangible asset impairment charges, gains or losses on sales of businesses, expense or income related to changes in the estimated fair value measurement of liabilities for contingent consideration, and other miscellaneous income or expense items.
Equity income from affiliates and depreciation included in segment profits is as follows:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
TotalPharma-ceutical
Animal
Health
TotalPharma-ceutical
Animal
Health
Total
Equity income from affiliates
$62 $— $62 $43 $— $43 $148 $— $148 $121 $— $121 
Depreciation
82 83 85 86 203 207 211 214 
Property, plant and equipment, net, by geographic area where located is as follows:
($ in millions)
September 30, 2025December 31, 2024
United States$15,482 $14,724 
Europe, Middle East and Africa8,665 7,548 
Asia Pacific (other than China and Japan)
948 982 
China208 202 
Japan147 143 
Latin America139 133 
Other50 47 
$25,639 $23,779 
The Company does not disaggregate assets on a products and services basis for internal management reporting and, therefore, such information is not presented.
v3.25.3
Insider Trading Arrangements
3 Months Ended
Sep. 30, 2025
Trading Arrangements, by Individual  
Rule 10b5-1 Arrangement Adopted false
Non-Rule 10b5-1 Arrangement Adopted false
Rule 10b5-1 Arrangement Terminated false
Non-Rule 10b5-1 Arrangement Terminated false
v3.25.3
Basis of Presentation (Policies)
9 Months Ended
Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Basis of Presentation Basis of Presentation
The accompanying unaudited condensed consolidated financial statements of Merck & Co., Inc. (Merck or the Company) have been prepared pursuant to the rules and regulations for reporting on Form 10-Q. Accordingly, certain information and disclosures required by accounting principles generally accepted in the United States (U.S.) for complete consolidated financial statements are not included herein. These interim statements should be read in conjunction with the audited financial statements and notes thereto included in Merck’s Form 10-K filed on February 25, 2025.
The results of operations of any interim period are not necessarily indicative of the results of operations for the full year. In the Company’s opinion, all adjustments necessary for a fair statement of these interim statements have been included and are of a normal and recurring nature.
Reclassifications Certain reclassifications have been made to prior year amounts to conform to the current year presentation.
Recently Issued Accounting Standards Not Yet Adopted
Recently Issued Accounting Standards Not Yet Adopted
In December 2023, the Financial Accounting Standards Board (FASB) issued guidance intended to improve the transparency of income tax disclosures by requiring consistent categories and disaggregation of information in the effective income tax rate reconciliation and income taxes paid disclosures by jurisdiction. The guidance also includes other amendments to improve the effectiveness of income tax disclosures by removing certain previously required disclosures. The guidance is effective for 2025 annual reporting and will result in incremental disclosures within the footnotes to the Company’s financial statements.
In November 2024, the FASB issued guidance intended to improve financial reporting by requiring entities to disclose additional information about specific expense categories at interim and annual reporting periods. The guidance is effective for 2027 annual reporting and 2028 interim reporting. Early adoption is permitted. The guidance, which can be applied on a prospective or retrospective basis, will result in incremental disclosures within the footnotes to the Company’s financial statements.
In September 2025, the FASB issued guidance intended to clarify and modernize the accounting for costs related to internal-use software. The guidance removes all references to software development project stages and clarifies the criteria entities should apply to begin capitalizing costs. The guidance is effective for 2028 annual and interim reporting and can be applied on a prospective, retrospective, or modified retrospective basis. Early adoption is permitted. 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.
v3.25.3
Acquisitions, Research Collaborations and Licensing Agreements (Tables)
9 Months Ended
Sep. 30, 2025
Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract]  
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed
The estimated fair values of assets acquired and liabilities assumed from the Elanco aqua business (inclusive of measurement period adjustments) are as follows:
($ in millions)
July 9, 2024
Inventories
$65 
Property, plant and equipment
66 
Product rights - Clynav (useful life 15 years) (1)
340 
Other product rights (useful lives 15 years) (1)
291 
Deferred tax asset
106 
Other assets and liabilities, net23 
Total identifiable net assets891 
Goodwill (2)
412 
Consideration transferred$1,303 
(1)     The estimated fair values of Clynav and other product rights were determined using an income approach, specifically the multi-period excess earnings method. The future probability-weighted net cash flows were discounted to present value utilizing a discount rate of 8.5%. Actual cash flows are likely to be different than those assumed.
(2)    The goodwill recognized is largely attributable to anticipated synergies expected to arise after the acquisition and was allocated to the Animal Health segment. This amount is expected to be deductible for tax purposes.
v3.25.3
Collaborative Arrangements (Tables)
9 Months Ended
Sep. 30, 2025
Collaborative Arrangements [Abstract]  
Schedule of Collaboration Arrangements
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Alliance revenue - Lynparza$379 $337 $1,061 $947 
Alliance revenue - Koselugo (1)
214 39 301 114 
Total alliance revenue$593 $376 $1,362 $1,061 
Cost of sales (2)
84 82 253 245 
Selling, general and administrative31 39 103 121 
Research and development19 31 57 
($ in millions)September 30, 2025December 31, 2024
Receivables from AstraZeneca included in Other current assets (3)
$436 $424 
Payables to AstraZeneca included in Accrued and other current liabilities (4)
713 
(1)    Amounts in 2025 include the $150 million upfront payment and $50 million regulatory milestone triggered in the third quarter as a result of the amendment to the collaboration agreement noted above.
(2)    Represents amortization of capitalized milestone payments.
(3)    Balance at September 30, 2025 includes a milestone receivable.
(4)    Balance at December 31, 2024 includes accrued milestone payments.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Alliance revenue - Lenvima$258 $251 $781 $755 
Cost of sales (1)
60 60 181 181 
Selling, general and administrative33 40 99 120 
Research and development10 18 
($ in millions)September 30, 2025December 31, 2024
Receivables from Eisai included in Other current assets
$258 $257 
(1)    Represents amortization of capitalized milestone payments.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Alliance revenue - Adempas/Verquvo$112 $102 $340 $306 
Net sales of Adempas recorded by Merck82 72 229 214 
Net sales of Verquvo recorded by Merck12 11 33 25 
Total sales$206 $185 $602 $545 
Cost of sales (1)
71 59 190 182 
Selling, general and administrative22 29 80 88 
Research and development11 27 55 82 
($ in millions)September 30, 2025December 31, 2024
Receivables from Bayer included in Other current assets
$168 $160 
Payables to Bayer included in Accrued and other current liabilities
93 82 
(1)    Includes amortization of intangible assets, cost of products sold by Merck, as well as Bayer’s share of profits from sales in Merck’s marketing territories.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Net sales of Lagevrio recorded by Merck
$138 $383 $323 $843 
Cost of sales (1)
81 204 178 491 
Selling, general and administrative
11 11 39 43 
Research and development
11 25 
($ in millions)September 30, 2025December 31, 2024
Payables to Ridgeback included in Accrued and other current liabilities (2)
$49 $68 
(1)    Includes cost of products sold by Merck, Ridgeback’s share of profits, royalty expense, amortization of capitalized milestone payments and inventory reserves.
(2)    Includes accrued royalties.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Cost of sales (1)
$67 $— $67 $— 
Selling, general and administrative 21 21 
Research and development
110 94 379 227 
($ in millions)September 30, 2025December 31, 2024
Receivables from Daiichi Sankyo included in Other current assets
$17 $
Payables to Daiichi Sankyo included in Accrued and other current liabilities (2)
869 817 
(1)    Represents Merck’s share of certain inventory-related costs.
(2)    Includes accrued continuation payment.
Summarized financial information related to this collaboration is as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Selling, general and administrative $$$19 $11 
Research and development (1)
96 93 272 255 
($ in millions)September 30, 2025December 31, 2024
Payables to Moderna included in Accrued and other current liabilities
$13 $57 
(1)    Includes amortization of shared facility costs.
v3.25.3
Restructuring (Tables)
9 Months Ended
Sep. 30, 2025
Restructuring and Related Activities [Abstract]  
Schedule of Charges Related to Restructuring Program Activities by Type of Cost
The following tables summarize the charges related to restructuring program activities by type of cost:
 Three Months Ended September 30, 2025Nine Months Ended September 30, 2025
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
Accelerated
Depreciation
Separation Costs
Other Exit Costs
Total
2025 Restructuring Program
Cost of sales$— $— $72 $72 $— $— $172 $172 
Research and development— — 233 233 — — 286 286 
Restructuring costs— — (3)(3)— 481 12 493 
— — 302 302 — 481 470 951 
2024 Restructuring Program
Cost of sales56 — (18)38 152 — (13)139 
Selling, general and administrative— — — — — — 
Restructuring costs— 44 50 — 13 170 183 
56 26 88 152 13 158 323 
$56 $$328 $390 $152 $494 $628 $1,274 
 Three Months Ended September 30, 2024Nine Months Ended September 30, 2024
($ in millions)
Accelerated Depreciation
Separation Costs
Other Exit Costs
Total
Accelerated
Depreciation
Separation Costs
Other Exit Costs
Total
2024 Restructuring Program
Cost of sales$40 $— $152 $192 $171 $— $203 $374 
Selling, general and administrative— — 31 31 — — 67 67 
Research and development— — — — — — 
Restructuring costs— 11 45 56 — 122 136 258 
$40 $11 $228 $279 $171 $122 $408 $701 
Schedule of Charges and Spending Relating to Restructuring Activities by Program
The following table summarizes the charges and spending related to restructuring program activities for the nine months ended September 30, 2025:
($ in millions)
Accelerated Depreciation
Separation
Costs
Other Exit Costs
Total
2025 Restructuring Program
Restructuring reserves January 1, 2025
$— $— $— $— 
Expenses
— 481 470 951 
(Payments) receipts, net— (7)(2)(9)
Non-cash activity— — (81)(81)
Restructuring reserves September 30, 2025
$— $474 $387 $861 
2024 Restructuring Program
Restructuring reserves January 1, 2025
$— $564 $— $564 
Expenses152 13 158 323 
(Payments) receipts, net— (78)(161)(239)
Non-cash activity(152)— (149)
Restructuring reserves September 30, 2025
$— $499 $— $499 
v3.25.3
Financial Instruments (Tables)
9 Months Ended
Sep. 30, 2025
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of Effect of Net Investment Hedges on OCI and the Consolidated Statement of Operations
The effects of the Company’s net investment hedges on OCI and the Condensed Consolidated Statement of Income are shown below:
Amount of Pretax (Gain) Loss Recognized in Other Comprehensive Income (1)
Amount of Pretax Gain Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing
Three Months Ended September 30,Nine Months Ended September 30,Three Months Ended September 30,Nine Months Ended September 30,
($ in millions)20252024202520242025202420252024
Net Investment Hedging Relationships
Foreign exchange contracts$(20)$$45 $$(3)$— $(11)$(2)
Euro-denominated notes(1)169 540 73 — — — — 
(1)    No amounts were reclassified from AOCL into income related to the sale of a subsidiary.
Schedule of Interest Rate Swaps Held
At September 30, 2025, the Company was a party to seven pay-floating, receive-fixed interest rate swap contracts designated as fair value hedges of a portion of fixed-rate notes as detailed in the table below.
September 30, 2025
($ in millions)
Par Value of Debt
Number of Interest Rate Swaps Held
Total Swap Notional Amount
4.50% notes due 2033
$1,500 $1,500 
    5.00% notes due 2053
1,500 250
Schedule of Amounts Recorded on Balance Sheet Related to Fair Value Hedges
The table below presents the location of amounts recorded in the Condensed Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges:
Carrying Amount of Hedged Liabilities
Cumulative Amount of Fair Value Hedging Adjustment Increase Included in the Carrying Amount
($ in millions)
September 30, 2025December 31, 2024September 30, 2025December 31, 2024
Balance Sheet Caption
Long-Term Debt
$1,819 $1,509 $80 $17 
Schedule of Fair Value of Derivatives on a Gross Basis Segregated between those Derivatives that are Designated as Hedging Instruments and those that are Not Designated as Hedging Instruments
Presented in the table below is the fair value of derivatives on a gross basis segregated between those derivatives that are designated as hedging instruments and those that are not designated as hedging instruments:
  September 30, 2025December 31, 2024
  Fair Value of DerivativeU.S. Dollar
Notional
Fair Value of DerivativeU.S. Dollar
Notional
($ in millions)AssetLiabilityAssetLiability
Derivatives Designated as Hedging InstrumentsBalance Sheet Caption
Interest rate swap contracts
Other Assets
$80 $— $1,750 $17 $— $1,500 
Foreign exchange contractsOther current assets55 — 4,681 323 — 8,662 
Foreign exchange contractsOther Assets37 — 2,274 66 — 2,125 
Foreign exchange contractsAccrued and other current liabilities— 246 5,694 — 162 
Foreign exchange contractsOther Noncurrent Liabilities— — — — 16 
  $172 $246 $14,399 $406 $$12,465 
Derivatives Not Designated as Hedging InstrumentsBalance Sheet Caption      
Foreign exchange contractsOther current assets$144 $— $12,498 $323 $— $12,544 
Foreign exchange contractsAccrued and other current liabilities— 246 15,975 — 343 13,551 
  $144 $246 $28,473 $323 $343 $26,095 
  $316 $492 $42,872 $729 $345 $38,560 
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:
 September 30, 2025December 31, 2024
($ in millions)AssetLiabilityAssetLiability
Gross amounts recognized in the condensed consolidated balance sheet$316 $492 $729 $345 
Gross amounts subject to offset in master netting arrangements not offset in the condensed consolidated balance sheet(246)(246)(299)(299)
Cash collateral received
(1)— (165)— 
Net amounts$69 $246 $265 $46 
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 September 30,Nine Months Ended September 30,
($ in millions)202520242025202420252024202520242025202420252024
Financial Statement Caption in which Effects of Fair Value or Cash Flow
Hedges are Recorded
Sales
Other (income) expense, net (1)
Other comprehensive income (loss)Sales
Other (income) expense, net (1)
Other comprehensive income (loss)
$17,276 $16,657 $(238)$(162)$219 $(10)$48,611 $48,544 $(281)$(151)$(257)$(210)
Loss (gain) on fair value hedging relationships:
Interest rate swap contracts
Hedged items— — 68 — — — — 62 42 — — 
Derivatives designated as hedging instruments— — (5)(69)— — — — (63)(43)— — 
Impact of cash flow hedging relationships:
Foreign exchange contracts
Amount of gain (loss) recognized in OCI on derivatives
— — — — 113 (325)— — — — (630)22 
(Decrease) increase in Sales as a result of AOCL reclassifications
(85)48 — — 85 (48)(35)146 — — 35 (146)
Interest rate contracts
Amount of gain recognized in Other (income) expense, net on derivatives
— — — — — — — — (1)(1)— — 
Amount of gain (loss) recognized in OCI on derivatives
— — — — 18 — — — — — 17 (1)
(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 September 30,Nine Months Ended September 30,
($ in millions)2025202420252024
Derivatives Not Designated as Hedging InstrumentsIncome Statement Caption
Foreign exchange contracts (1)
Other (income) expense, net$39 $(139)$(217)$(65)
Foreign exchange contracts (2)
Sales(8)10 26 (10)
(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:
 September 30, 2025December 31, 2024
 Amortized
Cost
Gross UnrealizedFair
Value
Amortized
Cost
Gross UnrealizedFair
Value
($ in millions)GainsLossesGainsLosses
U.S. government and agency securities$99 $— $— $99 $188 $— $— $188 
Commercial paper45 — — 45 348 — — 348 
Foreign government bonds
— — — — — — 
Total debt securities$145 $— $— $145 $536 $— $— $536 
Publicly traded equity securities (1)
1,546 920 
Total debt and publicly traded equity securities$1,691 $1,456 
(1)    Unrealized net gains of $367 million and $630 million were recorded in Other (income) expense, net in the third quarter and first nine months of 2025, respectively, on equity securities still held at September 30, 2025. Unrealized net losses (gains) of $42 million and $(82) million were recorded in Other (income) expense, net in the third quarter and first nine months of 2024, respectively, on equity securities still held at September 30, 2024.
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)September 30, 2025December 31, 2024
Assets
Investments
Commercial paper$— $45 $— $45 $— $348 $— $348 
Foreign government bonds
— — — — — — 
U.S. government and agency securities— — — — — 99 — 99 
Publicly traded equity securities1,116 — — 1,116 463 — — 463 
 1,116 46 — 1,162 463 447 — 910 
Other assets (1)
U.S. government and agency securities99 — — 99 89 — — 89 
Publicly traded equity securities (2)
430 — — 430 457 — — 457 
529 — — 529 546 — — 546 
Derivative assets (3)
Forward exchange contracts— 169 — 169 — 499 — 499 
Interest rate swaps
— 80 — 80 — 17 — 17 
Purchased currency options— 67 — 67 — 213 — 213 
 — 316 — 316 — 729 — 729 
Total assets$1,645 $362 $— $2,007 $1,009 $1,176 $— $2,185 
Liabilities
Other liabilities
Contingent consideration$— $— $— $— $— $— $193 $193 
Derivative liabilities (3)
Forward exchange contracts— 461 — 461 — 338 — 338 
Written currency options— 31 — 31 — — 
— 492 — 492 — 345 — 345 
Total liabilities$— $492 $— $492 $— $345 $193 $538 
(1)    Investments included in other assets are restricted as to use, including for the payment of benefits under employee benefit plans.
(2)    Includes securities with an aggregate fair value of $81 million at December 31, 2024, which were subject to a contractual sale restriction that expired in April 2025.
(3)    The fair value determination of derivatives includes the impact of the credit risk of counterparties to the derivatives and the Company’s own credit risk, the effects of which were not significant.
Schedule of Information About the Changes in Liabilities for Contingent Consideration
Summarized information about the changes in the fair value of liabilities for contingent consideration associated with business combinations is as follows:
($ in millions)20252024
Fair value January 1$193 $354 
Changes in estimated fair value (1)
(52)
Payments (2)
(141)(148)
Fair value September 30
$— $208 
(1)    Recorded in Cost of sales, Research and development expenses, and Other (income) expense, net. Includes cumulative translation adjustments. Amount in 2025 includes the reversal of $45 million for a Zerbaxa sales-based milestone as it was determined that payment was not probable.
(2)    Amount in both periods reflects payments related to the 2016 termination of the Sanofi Pasteur MSD joint venture. Amount in 2025 also includes a $25 million payment related to the achievement of a sales-based milestone for Zerbaxa.
v3.25.3
Inventories (Tables)
9 Months Ended
Sep. 30, 2025
Inventory Disclosure [Abstract]  
Schedule of Inventory, current
Inventories consisted of:
($ in millions)September 30, 2025December 31, 2024
Finished goods$2,249 $2,022 
Raw materials and work in process10,165 8,831 
Supplies325 289 
Total12,739 11,142 
Decrease to LIFO cost(883)(840)
 $11,856 $10,302 
Recognized as:
Inventories$6,444 $6,109 
Other Assets5,412 4,193 
Schedule of Inventory, noncurrent
Inventories consisted of:
($ in millions)September 30, 2025December 31, 2024
Finished goods$2,249 $2,022 
Raw materials and work in process10,165 8,831 
Supplies325 289 
Total12,739 11,142 
Decrease to LIFO cost(883)(840)
 $11,856 $10,302 
Recognized as:
Inventories$6,444 $6,109 
Other Assets5,412 4,193 
v3.25.3
Equity (Tables)
9 Months Ended
Sep. 30, 2025
Equity [Abstract]  
Schedule of Equity
Three Months Ended September 30,
   Common StockOther
Paid-In
Capital
Retained
Earnings
Accumulated
Other
Comprehensive
Loss
 Treasury StockNon-
controlling
Interests
Total
($ and shares in millions except per share amounts)SharesPar ValueSharesCost
Balance at July 1, 2024
3,577 $1,788 $44,362 $60,187 $(5,361)1,041 $(57,394)$66 $43,648 
Net income attributable to Merck & Co., Inc.
— — — 3,157 — — — — 3,157 
Other comprehensive loss, net of taxes— — — — (10)— — — (10)
Cash dividends declared on common stock ($0.77 per share)
— — — (1,960)— — — — (1,960)
Treasury stock shares purchased— — — — — (444)— (444)
Share-based compensation plans and other— — 168 — — — — 177 
Net income attributable to noncontrolling interests— — — — — — — 
Distributions attributable to noncontrolling interests— — — — — — — (12)(12)
Balance at September 30, 20243,577 $1,788 $44,530 $61,384 $(5,371)1,045 $(57,829)$58 $44,560 
Balance at July 1, 2025
3,577 $1,788 $44,644 $68,477 $(5,421)1,074 $(60,495)$67 $49,060 
Net income attributable to Merck & Co., Inc.— — — 5,785 — — — — 5,785 
Other comprehensive income, net of taxes
— — — — 219 — — — 219 
Cash dividends declared on common stock ($0.81 per share)
— — — (2,031)— — — — (2,031)
Treasury stock shares purchased— — — — — 16 (1,324)— (1,324)
Share-based compensation plans and other— — 188 — — — 20 — 208 
Net income attributable to noncontrolling interests— — — — — — — 
Distributions attributable to noncontrolling interests— — — — — — — (12)(12)
Balance at September 30, 20253,577 $1,788 $44,832 $72,231 $(5,202)1,090 $(61,799)$57 $51,907 
Nine Months Ended September 30,
   Common StockOther
Paid-In
Capital
Retained
Earnings
Accumulated
Other
Comprehensive
Loss
 Treasury StockNon-
controlling
Interests
Total
($ and shares in millions except per share amounts)SharesPar ValueSharesCost
Balance at January 1, 2024
3,577 $1,788 $44,509 $53,895 $(5,161)1,045 $(57,450)$54 $37,635 
Net income attributable to Merck & Co., Inc.
— — — 13,374 — — — — 13,374 
Other comprehensive loss, net of taxes— — — — (210)— — — (210)
Cash dividends declared on common stock ($2.31 per share)
— — — (5,885)— — — — (5,885)
Treasury stock shares purchased— — — — — (817)— (817)
Share-based compensation plans and other— — 21 — — (7)438 460 
Net income attributable to noncontrolling interests— — — — — — — 15 15 
Distributions attributable to noncontrolling interests— — — — — — — (12)(12)
Balance at September 30, 20243,577 $1,788 $44,530 $61,384 $(5,371)1,045 $(57,829)$58 $44,560 
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.— — — 15,291 — — — — 15,291 
Other comprehensive loss, net of taxes— — — — (257)— — — (257)
Cash dividends declared on common stock ($2.43 per share)
— — — (6,129)— — — — (6,129)
Treasury stock shares purchased— — — — — 46 (3,832)— (3,832)
Share-based compensation plans and other— — 128 — — (5)336 — 464 
Net income attributable to noncontrolling interests— — — — — — — 10 10 
Distributions attributable to noncontrolling interests— — — — — — — (12)(12)
Balance at September 30, 20253,577 $1,788 $44,832 $72,231 $(5,202)1,090 $(61,799)$57 $51,907 
v3.25.3
Pension and Other Postretirement Benefit Plans (Tables)
9 Months Ended
Sep. 30, 2025
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
September 30,
Nine Months Ended
September 30,
2025202420252024
($ in millions)U.S.InternationalU.S.InternationalU.S.InternationalU.S.International
Service cost$100 $57 $100 $60 $279 $171 $273 $182 
Interest cost143 78 134 74 425 225 403 220 
Expected return on plan assets(210)(159)(206)(139)(630)(454)(621)(416)
Amortization of unrecognized prior service credit
— (4)— (3)— (12)— (10)
Net loss amortization
16 12 42 30 
Termination benefits— — — — — 
Curtailments(16)— — (16)— — 
 $58 $(41)$41 $(7)$125 $(78)$90 $(20)
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
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Service cost$$$29 $23 
Interest cost15 14 46 42 
Expected return on plan assets(13)(20)(39)(60)
Amortization of unrecognized prior service credit(10)(11)(30)(32)
Net gain amortization(12)(14)(33)(38)
 $(11)$(24)$(27)$(65)
v3.25.3
Other (Income) Expense, Net (Tables)
9 Months Ended
Sep. 30, 2025
Other Income and Expenses [Abstract]  
Schedule of Other (Income) Expense, Net
Other (income) expense, net, consisted of: 
 Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
Interest income$(96)$(127)$(274)$(269)
Interest expense327 330 946 943 
Exchange losses56 33 224 177 
(Income) loss from investments in equity securities, net (1)
(373)31 (563)(169)
Net periodic defined benefit plan (credit) cost other than service cost(152)(157)(452)(476)
Other, net— (272)(162)(357)
 $(238)$(162)$(281)$(151)
(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.
v3.25.3
Earnings Per Share (Tables)
9 Months Ended
Sep. 30, 2025
Earnings Per Share [Abstract]  
Schedule of Calculations of Earnings Per Share
The calculations of earnings per share are as follows:
 Three Months Ended
September 30,
Nine Months Ended
September 30,
($ and shares in millions except per share amounts)2025202420252024
Net Income Attributable to Merck & Co., Inc.
$5,785 $3,157 $15,291 $13,374 
Average common shares outstanding2,495 2,534 2,509 2,534 
Common shares issuable (1)
Average common shares outstanding assuming dilution 2,498 2,541 2,514 2,543 
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders
$2.32 $1.25 $6.09 $5.28 
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders
$2.32 $1.24 $6.08 $5.26 
(1)    Issuable primarily under share-based compensation plans.
v3.25.3
Other Comprehensive Income (Loss) (Tables)
9 Months Ended
Sep. 30, 2025
Equity [Abstract]  
Schedule of Changes in AOCI by Component
Changes in each component of other comprehensive income (loss) are as follows:
Three Months Ended September 30,
($ in millions)DerivativesEmployee
Benefit
Plans
Foreign Currency
Translation
Adjustment
Accumulated Other
Comprehensive
Loss
Balance July 1, 2024, net of taxes
$173 $(2,808)$(2,726)$(5,361)
Other comprehensive income (loss) before reclassification adjustments, pretax(325)— 279 (46)
Tax68 (3)20 85 
Other comprehensive income (loss) before reclassification adjustments, net of taxes(257)(3)299 39 
Reclassification adjustments, pretax(49)
(1)
(14)
(2)
— (63)
Tax10 — 14 
Reclassification adjustments, net of taxes(39)

(10)

— (49)
Other comprehensive income (loss), net of taxes(296)(13)299 (10)
Balance September 30, 2024, net of taxes
$(123)$(2,821)$(2,427)$(5,371)
Balance July 1, 2025, net of taxes
$(385)$(2,353)$(2,683)$(5,421)
Other comprehensive income (loss) before reclassification adjustments, pretax113 93 (64)142 
Tax(24)39 16 
Other comprehensive income (loss) before reclassification adjustments, net of taxes89 94 (25)158 
Reclassification adjustments, pretax103 
(1)
(22)
(2)
— 81 
Tax(22)— (20)
Reclassification adjustments, net of taxes81 

(20)

— 61 
Other comprehensive income (loss), net of taxes170 74 (25)219 
Balance September 30, 2025, net of taxes
$(215)$(2,279)$(2,708)$(5,202)

Nine Months Ended September 30,
($ in millions)DerivativesEmployee
Benefit
Plans
Foreign Currency
Translation
Adjustment
Accumulated Other
Comprehensive
Loss
Balance January 1, 2024, net of taxes
$(24)$(2,793)$(2,344)$(5,161)
Other comprehensive income (loss) before reclassification adjustments, pretax22 (103)(75)
Tax(5)(5)— (10)
Other comprehensive income (loss) before reclassification adjustments, net of taxes17 (103)(85)
Reclassification adjustments, pretax(147)
(1)
(44)
(2)
20 (171)
Tax31 15 — 46 
Reclassification adjustments, net of taxes(116)(29)20 (125)
Other comprehensive income (loss), net of taxes(99)(28)(83)(210)
Balance September 30, 2024, net of taxes
$(123)$(2,821)$(2,427)$(5,371)
Balance January 1, 2025, net of taxes
$242 $(2,327)$(2,860)$(4,945)
Other comprehensive income (loss) before reclassification adjustments, pretax(630)91 270 (269)
Tax132 — (118)14 
Other comprehensive income (loss) before reclassification adjustments, net of taxes(498)91 152 (255)
Reclassification adjustments, pretax52 
(1)
(40)
(2)
— 12 
Tax(11)(3)— (14)
Reclassification adjustments, net of taxes41 (43)— (2)
Other comprehensive income (loss), net of taxes(457)48 152 (257)
Balance September 30, 2025, net of taxes
$(215)$(2,279)$(2,708)$(5,202)
(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).
v3.25.3
Segment Reporting (Tables)
9 Months Ended
Sep. 30, 2025
Segment Reporting [Abstract]  
Schedule of Sales from Products
Sales of the Company’s products were as follows:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
 ($ in millions)U.S.Int’lTotalU.S.Int’lTotalU.S.Int’lTotalU.S.Int’lTotal
Pharmaceutical:
Oncology
Keytruda$4,879 $3,263 $8,142 $4,500 $2,929 $7,429 $13,936 $9,367 $23,303 $13,031 $8,614 $21,646 
Alliance revenue-Lynparza (1)
184 195 379 161 177 337 503 558 1,061 449 498 947 
Alliance revenue-Lenvima (1)
177 81 258 173 78 251 545 236 781 523 233 755 
Welireg161 35 196 127 12 139 422 74 496 320 29 349 
Alliance revenue-Reblozyl (2)
111 25 136 82 18 100 299 62 361 215 45 261 
Vaccines
Gardasil/Gardasil 9
1,154 595 1,749 1,020 1,285 2,306 2,235 1,967 4,202 2,045 4,988 7,032 
ProQuad/M-M-R II/Varivax
554 130 684 572 131 703 1,457 374 1,832 1,500 391 1,891 
Vaxneuvance134 91 226 137 103 239 409 276 685 397 251 647 
RotaTeq141 63 204 131 62 193 366 187 554 388 185 572 
Capvaxive
238 244 47 — 47 473 480 47 — 47 
Pneumovax 23
10 35 45 19 49 68 13 111 124 36 152 188 
Hospital Acute Care
Bridion392 47 439 339 81 420 1,181 161 1,341 1,020 296 1,315 
Prevymis128 138 266 101 107 208 345 357 702 265 305 570 
Zerbaxa49 32 81 39 26 64 136 89 225 106 77 182 
Dificid30 13 43 83 13 96 185 37 222 231 30 261 
Cardiovascular
Winrevair
335 25 360 147 149 926 49 976 216 219 
Alliance revenue-Adempas/Verquvo (3)
103 112 96 102 308 32 340 283 22 306 
Adempas— 82 82 — 72 72 — 229 229 — 214 214 
Virology
Lagevrio24 114 138 84 299 383 90 233 323 144 699 843 
Isentress/Isentress HD
44 37 82 54 48 102 144 114 258 147 155 302 
Delstrigo
13 64 77 15 50 65 42 185 228 42 139 180 
Pifeltro
29 14 43 31 12 42 86 43 128 86 37 123 
Neuroscience
Belsomra28 19 47 20 58 78 59 77 137 53 124 177 
Immunology
Simponi— — — — 189 189 — — — — 545 545 
Remicade— — — — 41 41 — — — — 115 115 
Diabetes
Januvia258 124 382 67 211 278 819 483 1,302 428 674 1,102 
Janumet78 165 243 15 190 204 210 530 741 70 610 679 
Other pharmaceutical (4)
239 716 953 167 466 638 558 1,713 2,268 521 1,364 1,890 
Total Pharmaceutical segment sales9,493 6,118 15,611 8,227 6,717 14,943 25,747 17,552 43,299 22,563 20,795 43,358 
Animal Health:
Livestock213 811 1,023 194 692 886 598 2,312 2,909 529 2,044 2,573 
Companion Animal291 301 592 293 307 601 907 1,033 1,940 888 1,019 1,907 
Total Animal Health segment sales504 1,112 1,615 487 999 1,487 1,505 3,345 4,849 1,417 3,063 4,480 
Total segment sales9,997 7,230 17,226 8,714 7,716 16,430 27,252 20,897 48,148 23,980 23,858 47,838 
Other (5)
15 34 50 22 206 227 119 343 463 109 597 706 
 $10,012 $7,264 $17,276 $8,736 $7,922 $16,657 $27,371 $21,240 $48,611 $24,089 $24,455 $48,544 
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 $214 million and $39 million in the third quarter of 2025 and 2024, respectively, and $301 million and $114 million in the first nine months of 2025 and 2024, respectively (see Note 3).
(5)    Other is primarily comprised of miscellaneous corporate revenue, including revenue hedging activities which (decreased) increased sales by $(61) million and $156 million for the nine months ended September 30, 2025 and 2024, respectively, as well as revenue from third-party manufacturing arrangements (including sales to Organon & Co.). Other for the nine months ended September 30, 2025 and 2024 also includes $111 million and $91 million, respectively, related to upfront and milestone payments received by Merck for out-licensing arrangements.
Schedule of Consolidated Sales by Geographic Area
Consolidated sales by geographic area where derived are as follows:
Three Months Ended
September 30,
Nine Months Ended
September 30,
($ in millions)2025202420252024
United States$10,012 $8,736 $27,371 $24,089 
Europe, Middle East and Africa3,680 3,583 10,789 10,661 
Latin America905 936 2,556 2,591 
Asia Pacific (other than China and Japan)764 823 2,238 2,294 
Japan712 938 2,007 2,445 
China405 1,017 1,553 4,606 
Other798 624 2,097 1,858 
 $17,276 $16,657 $48,611 $48,544 
Schedule of Reconciliation of Segment Profits to Income before Taxes
A reconciliation of segment profits to Income Before Taxes is as follows:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
TotalPharma-ceutical
Animal
Health
TotalPharma-ceutical
Animal
Health
Total
Segment sales$15,611 $1,615 $17,226 $14,943 $1,487 $16,430 $43,299 $4,849 $48,148 $43,358 $4,480 $47,838 
Less segment costs: (1)
Cost of sales1,664 710 1,904 613 4,838 1,968 5,319 1,838 
Selling, general and administrative1,469 277 1,519 268 4,327 822 4,462 791 
Research and development (2)
— 118 — 95 — 323 — 276 
Other segment items (3)
(60)(1)(27)(130)(1)(74)
Total segment profits$12,538 $511 $13,049 $11,547 $510 $12,057 $34,264 $1,737 $36,001 $33,651 $1,574 $35,225 
Other profits117 235 391 
Unallocated:
Interest income96 127 274 269 
Interest expense(327)(330)(946)(943)
Amortization(623)(633)(1,820)(1,720)
Depreciation(449)(467)(1,345)(1,368)
Research and development(3,839)(5,716)(11,159)(12,926)
Restructuring costs(47)(56)(676)(258)
Other unallocated, net(1,119)(1,009)(2,917)(2,904)
$6,745 $4,090 $17,647 $15,766 
(1)    The significant expense categories and amounts align with the segment level information that is regularly provided to the chief operating decision maker.
(2)    Human health-related research and development expenses incurred by Merck Research Laboratories are not allocated to segment profits as noted below.
(3)    Includes equity (income) loss from affiliates and other miscellaneous non-operating expenses.
Schedule of Equity Loss from Affiliates and Depreciation Included in Segment Profits
Equity income from affiliates and depreciation included in segment profits is as follows:
Three Months Ended September 30,Nine Months Ended September 30,
2025202420252024
($ in millions)
Pharma-
ceutical
Animal
Health
Total
Pharma-
ceutical
Animal
 Health
TotalPharma-ceutical
Animal
Health
TotalPharma-ceutical
Animal
Health
Total
Equity income from affiliates
$62 $— $62 $43 $— $43 $148 $— $148 $121 $— $121 
Depreciation
82 83 85 86 203 207 211 214 
Schedule of Property, Plant and Equipment, Net by Geographic Area
Property, plant and equipment, net, by geographic area where located is as follows:
($ in millions)
September 30, 2025December 31, 2024
United States$15,482 $14,724 
Europe, Middle East and Africa8,665 7,548 
Asia Pacific (other than China and Japan)
948 982 
China208 202 
Japan147 143 
Latin America139 133 
Other50 47 
$25,639 $23,779 
v3.25.3
Acquisitions, Research Collaborations and Licensing Agreements - Narrative (Details)
$ in Millions
1 Months Ended 3 Months Ended 9 Months Ended 15 Months Ended
Oct. 31, 2025
USD ($)
Sep. 30, 2025
USD ($)
Mar. 31, 2025
USD ($)
Sep. 30, 2024
USD ($)
Jul. 31, 2024
USD ($)
aqua_facility
Mar. 31, 2024
USD ($)
Dec. 31, 2025
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2024
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2024
USD ($)
Sep. 30, 2025
USD ($)
May 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Feb. 29, 2024
USD ($)
Business Combination [Line Items]                              
Research and development               $ 4,234.0 $ 5,862.0 $ 11,903.0 $ 13,354.0        
Property, plant and equipment, net   $ 25,639.0           25,639.0   25,639.0   $ 25,639.0   $ 23,779.0  
Intangible assets   15,313.0           15,313.0   15,313.0   15,313.0   $ 16,370.0  
Elanco Animal Health Incorporated Aqua Business                              
Business Combination [Line Items]                              
Cash paid for acquisition of business         $ 1,300.0                    
Aqua manufacturing facilities | aqua_facility         2,000,000                    
Verona Pharma plc | Subsequent Event                              
Business Combination [Line Items]                              
Consideration transferred, asset acquisition $ 10,500.0                            
LaNova Medicines Ltd                              
Business Combination [Line Items]                              
Research and development               300.0   300.0          
HRS-5346 , Jiangsu Hengrui Pharmaceuticals Co., Ltd.                              
Business Combination [Line Items]                              
Research and development                   200.0          
Jiangsu Hengrui Pharmaceuticals Co., Ltd.                              
Business Combination [Line Items]                              
Future contingent developmental milestone payments (up to)                         $ 92.5    
Future regulatory milestone payments (up to)                         177.5    
Maximum aggregate sales-based milestone payments                         $ 1,500.0    
WuXi Vaccines' facility                              
Business Combination [Line Items]                              
Consideration transferred, asset acquisition     $ 437.0                        
WuXi Vaccines' facility | Asset under Construction                              
Business Combination [Line Items]                              
Property, plant and equipment, net     $ 759.0                        
MK-1045/CN201, Curon Biopharmaceutical                              
Business Combination [Line Items]                              
Research and development                 750.0   750.0        
Consideration transferred, asset acquisition       $ 700.0                      
Future contingent developmental milestone payments (up to)       300.0         300.0   300.0        
Future regulatory milestone payments (up to)       300.0         300.0   300.0        
Eyebiotech Limited                              
Business Combination [Line Items]                              
Research and development                 1,350.0   1,350.0        
Consideration transferred, asset acquisition         $ 1,200.0                    
Future contingent developmental milestone payments (up to)         1,000.0                    
Future regulatory milestone payments (up to)         200.0                    
Maximum aggregate sales-based milestone payments         500.0                    
Asset acquisition, transaction costs         207.0                    
Developmental milestone payment triggered and paid                 100.0 100.0 100.0 200.0      
Net assets acquired         $ 21.0                    
Harpoon Therapeutics, Inc.                              
Business Combination [Line Items]                              
Research and development                     656.0        
Consideration transferred, asset acquisition           $ 765.0                  
Asset acquisition, transaction costs           $ 56.0                  
Net assets acquired                     165.0        
Forecast | sac-TMT                              
Business Combination [Line Items]                              
Research and development arrangement, contract to perform for others, compensation earned 700.0                            
Dr. Falk Pharma | Forecast                              
Business Combination [Line Items]                              
Research and development             $ 150.0                
Third-Party | MK-1045/CN201, Curon Biopharmaceutical                              
Business Combination [Line Items]                              
Net assets acquired       $ 128.0         $ 128.0   $ 128.0        
Alteogen Inc.                              
Business Combination [Line Items]                              
Aggregate, regulatory milestones payments, maximum                             $ 51.0
Sales milestone payments                             $ 1,000.0
Sales based royalty percentage                             2.00%
Collaborative arrangement, rights and obligations, probable contingent payments   680.0                          
Alteogen Inc. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Keytruda Qlex                              
Business Combination [Line Items]                              
Liabilities resulting milestone payments   705.0           705.0   705.0   705.0      
Intangible assets   $ 705.0           $ 705.0   $ 705.0   $ 705.0      
Alteogen Inc. | Subsequent Event | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Keytruda Qlex                              
Business Combination [Line Items]                              
Liabilities resulting milestone payments $ 25.0                            
v3.25.3
Acquisitions, Research Collaborations and Licensing Agreements - Estimated Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Jul. 09, 2024
Business Combination [Line Items]      
Goodwill $ 21,587 $ 21,668  
Elanco Animal Health Incorporated Aqua Business      
Business Combination [Line Items]      
Inventories     $ 65
Property, plant and equipment     66
Deferred tax asset     106
Other assets and liabilities, net     23
Total identifiable net assets     891
Goodwill     412
Consideration transferred     $ 1,303
Discount rate     8.50%
Elanco Animal Health Incorporated Aqua Business | Product Rights      
Business Combination [Line Items]      
Product rights and other     $ 340
Estimated useful life of intangible assets     15 years
Elanco Animal Health Incorporated Aqua Business | Other Product Rights      
Business Combination [Line Items]      
Product rights and other     $ 291
Estimated useful life of intangible assets     15 years
v3.25.3
Collaborative Arrangements - AstraZeneca PLC - Narrative (Details) - USD ($)
3 Months Ended 9 Months Ended
Dec. 31, 2025
Sep. 30, 2025
Sep. 30, 2025
Sep. 30, 2024
Jan. 31, 2028
Jan. 31, 2027
Jan. 31, 2026
Koselugo | Licenses and Other              
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Finite-lived intangible assets   $ 41,000,000 $ 41,000,000        
Lynparza | Licenses and Other              
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Finite-lived intangible assets   926,000,000 926,000,000        
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          
Aggregate, regulatory milestones payments, maximum   75,000,000 75,000,000        
Sales milestone payments   235,000,000 235,000,000        
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 $ 150,000,000
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Koselugo              
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Upfront payments recognized as revenue   50,000,000 50,000,000        
Sales based milestone payments     100,000,000        
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Koselugo | Forecast              
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Upfront payments recognized as revenue $ 50,000,000            
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Lynparza              
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Aggregate, regulatory milestones payments, maximum   0 0        
Sales milestone payments   $ 2,000,000,000.0 2,000,000,000.0        
Sales based milestone payments     $ 600,000,000        
Regulatory milestone payments       $ 245,000,000      
v3.25.3
Collaborative Arrangements - AstraZeneca PLC (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Cost of sales $ 3,855 $ 4,080 $ 10,831 $ 11,365  
Selling, general and administrative 2,633 2,731 7,835 7,952  
Research and development 4,234 5,862 11,903 13,354  
Other current assets 47,557   47,557   $ 38,782
Accrued and other current liabilities 16,186   16,186   15,694
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Revenue from collaborative arrangement 593 376 1,362 1,061  
Cost of sales 84 82 253 245  
Selling, general and administrative 31 39 103 121  
Research and development 3 19 31 57  
Other current assets 436   436   424
Accrued and other current liabilities 4   4   $ 713
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 379 337 1,061 947  
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 214 $ 39 301 $ 114  
Upfront payments recognized as revenue 150        
AstraZeneca | Koselugo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Upfront payments recognized as revenue $ 50   $ 50    
v3.25.3
Collaborative Arrangements - Eisai Co., Ltd. - Narrative (Details) - Alliance revenue - Lenvima - USD ($)
9 Months Ended
Sep. 30, 2024
Sep. 30, 2025
Licenses and Other    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Finite-lived intangible assets   $ 261,000,000
Eisai | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement    
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]    
Sales based milestone payments $ 125,000,000  
Sales milestone payments   2,300,000,000
Aggregate, regulatory milestones payments, maximum   $ 0
v3.25.3
Collaborative Arrangements - Eisai Co., Ltd. (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Cost of sales $ 3,855 $ 4,080 $ 10,831 $ 11,365  
Selling, general and administrative 2,633 2,731 7,835 7,952  
Research and development 4,234 5,862 11,903 13,354  
Other current assets 47,557   47,557   $ 38,782
Eisai | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Revenue from collaborative arrangement 258 251 781 755  
Cost of sales 60 60 181 181  
Selling, general and administrative 33 40 99 120  
Research and development 2 $ 4 10 $ 18  
Other current assets $ 258   $ 258   $ 257
v3.25.3
Collaborative Arrangements - Bayer AG (Details) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Sales $ 17,276,000,000 $ 16,657,000,000 $ 48,611,000,000 $ 48,544,000,000  
Cost of sales 3,855,000,000 4,080,000,000 10,831,000,000 11,365,000,000  
Selling, general and administrative 2,633,000,000 2,731,000,000 7,835,000,000 7,952,000,000  
Research and development 4,234,000,000 5,862,000,000 11,903,000,000 13,354,000,000  
Other current assets 47,557,000,000   47,557,000,000   $ 38,782,000,000
Accrued and other current liabilities 16,186,000,000   16,186,000,000   15,694,000,000
Adempas | Licenses and Other          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Finite-lived intangible assets 312,000,000   312,000,000    
Verquvo | Licenses and Other          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Finite-lived intangible assets 41,000,000   41,000,000    
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Sales milestone payments 0   0    
Revenue from collaborative arrangement 112,000,000 102,000,000 340,000,000 306,000,000  
Sales 206,000,000 185,000,000 602,000,000 545,000,000  
Cost of sales 71,000,000 59,000,000 190,000,000 182,000,000  
Selling, general and administrative 22,000,000 29,000,000 80,000,000 88,000,000  
Research and development 11,000,000 27,000,000 55,000,000 82,000,000  
Other current assets 168,000,000   168,000,000   160,000,000
Accrued and other current liabilities 93,000,000   93,000,000   $ 82,000,000
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Adempas          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Sales 82,000,000 72,000,000 229,000,000 214,000,000  
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Verquvo          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Sales $ 12,000,000 $ 11,000,000 $ 33,000,000 $ 25,000,000  
v3.25.3
Collaborative Arrangements - Ridgeback Biotherapeutics LP (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Sales $ 17,276 $ 16,657 $ 48,611 $ 48,544  
Cost of sales 3,855 4,080 10,831 11,365  
Selling, general and administrative 2,633 2,731 7,835 7,952  
Accrued and other current liabilities 16,186   16,186   $ 15,694
Ridgeback Biotherapeutics LP | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Cost of sales 81 204 178 491  
Selling, general and administrative 11 11 39 43  
Research and development 11 5 25 7  
Accrued and other current liabilities 49   49   $ 68
Ridgeback Biotherapeutics LP | Lagevrio | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Sales $ 138 $ 383 $ 323 $ 843  
v3.25.3
Collaborative Arrangements - Daiicho Sankyo - Narrative (Details)
$ in Millions
1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
Aug. 31, 2024
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2024
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2024
USD ($)
Dec. 31, 2023
USD ($)
candidate
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Research and development   $ 4,234 $ 5,862 $ 11,903 $ 13,354  
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Number of antibody drug conjugates obtained right and obligations | candidate           3
Aggregate upfront payments due upon execution in collaborative arrangement           $ 4,000
Refundable upfront payments in collaborative arrangement           1,000
Maximum aggregate contingent milestone payments, per product, in collaborative arrangement           5,500
Research and development   $ 110 $ 94 $ 379 $ 227 $ 5,500
Sales based royalty percentage 5.00%         5.00%
Upfront cash payment $ 170          
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Ifinatamab Deruxtecan            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Refundable upfront payments in collaborative arrangement           $ 500
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Patritumab Deruxtecan            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Refundable upfront payments in collaborative arrangement           500
Aggregate upfront payments due upon lapse of time in collaborative arrangement           750
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Raludotatug Deruxtecan            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Aggregate upfront payments due upon lapse of time in collaborative arrangement           $ 750
Liable contracted portion of research and development expenses to incur costs for in collaborative arrangement, percentage           75.00%
Liable contracted portion of research and development expenses to incur costs for in collaborative arrangement           $ 2,000
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Patritumab Deruxtecan and Ralduotatug Deruxtecan            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Aggregate upfront payments due upon lapse of time in collaborative arrangement           $ 1,500
v3.25.3
Collaborative Arrangements - Schedule of Daiicho Sankyo (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2023
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Cost of sales $ 3,855 $ 4,080 $ 10,831 $ 11,365    
Selling, general and administrative 2,633 2,731 7,835 7,952    
Research and development 4,234 5,862 11,903 13,354    
Other current assets 10,779   10,779     $ 8,706
Accrued and other current liabilities 16,186   16,186     15,694
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement            
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]            
Cost of sales 67 0 67 0    
Selling, general and administrative 8 5 21 21    
Research and development 110 $ 94 379 $ 227 $ 5,500  
Other current assets 17   17     8
Accrued and other current liabilities $ 869   $ 869     $ 817
v3.25.3
Collaborative Arrangements - Moderna, Inc. - Narrative (Details)
$ in Millions
Sep. 30, 2025
USD ($)
Moderna, Inc. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]  
Capitalization of shared costs $ 235
v3.25.3
Collaborative Arrangements - Moderna, Inc. (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Selling, general and administrative $ 2,633 $ 2,731 $ 7,835 $ 7,952  
Research and development 4,234 5,862 11,903 13,354  
Accrued and other current liabilities 16,186   16,186   $ 15,694
Moderna, Inc. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement          
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Selling, general and administrative 7 5 19 11  
Research and development 96 $ 93 272 $ 255  
Accrued and other current liabilities $ 13   $ 13   $ 57
v3.25.3
Collaborative Arrangements - Bristol Meyers Squibb Company - Narrative (Details) - Bristol Myers Squibb Company - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Licensing Agreements        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]        
Royalty rate, deduction     0.50  
Licensing Agreements | Alliance Revenue - Reblozyl        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]        
Sales milestone payments $ 80   $ 80  
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]        
Revenue from collaborative arrangement $ 136 $ 100 $ 361 $ 261
Minimum | Licensing Agreements        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]        
Royalty rate     20.00%  
Maximum | Licensing Agreements        
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]        
Royalty rate     24.00%  
v3.25.3
Restructuring - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs $ 390   $ 1,274  
Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Expected restructuring and related cost 3,000   $ 3,000  
Estimate of cumulative pre tax costs that will be cash     60.00%  
Total pretax restructuring costs 302   $ 951  
Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Expected restructuring and related cost 4,000   $ 4,000  
Estimate of cumulative pre tax costs that will be noncash     60.00%  
Total pretax restructuring costs 88 $ 279 $ 323 $ 701
Cumulative costs since program inception $ 1,400   $ 1,400  
v3.25.3
Restructuring - Schedule of Charges Activities by Type of Cost (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs $ 390   $ 1,274  
Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 302   951  
Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 88 $ 279 323 $ 701
Accelerated Depreciation        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 56   152  
Accelerated Depreciation | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 56 40 152 171
Separation Costs        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 6   494  
Separation Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   481  
Separation Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 6 11 13 122
Other Exit Costs        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 328   628  
Other Exit Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 302   470  
Other Exit Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 26 228 158 408
Cost of sales | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 72   172  
Cost of sales | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 38 192 139 374
Cost of sales | Accelerated Depreciation | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Cost of sales | Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 56 40 152 171
Cost of sales | Separation Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Cost of sales | Separation Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0 0 0 0
Cost of sales | Other Exit Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 72   172  
Cost of sales | Other Exit Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs (18) 152 (13) 203
Selling, general and administrative | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0 31 1 67
Selling, general and administrative | Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0 0 0 0
Selling, general and administrative | Separation Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0 0 0 0
Selling, general and administrative | Other Exit Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0 31 1 67
Research and development | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 233   286  
Research and development | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs   0   2
Research and development | Accelerated Depreciation | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Research and development | Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs   0   0
Research and development | Separation Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Research and development | Separation Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs   0   0
Research and development | Other Exit Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 233   286  
Research and development | Other Exit Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs   0   2
Restructuring costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs (3)   493  
Restructuring costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 50 56 183 258
Restructuring costs | Accelerated Depreciation | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   0  
Restructuring costs | Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0 0 0 0
Restructuring costs | Separation Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 0   481  
Restructuring costs | Separation Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs 6 11 13 122
Restructuring costs | Other Exit Costs | Restructuring Program, 2025        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs (3)   12  
Restructuring costs | Other Exit Costs | Restructuring Program, 2024        
Restructuring Cost and Reserve [Line Items]        
Total pretax restructuring costs $ 44 $ 45 $ 170 $ 136
v3.25.3
Restructuring - Schedule of Activities by Program (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Restructuring Reserve [Roll Forward]        
Expenses $ 390   $ 1,274  
Restructuring Program, 2025        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 302   951  
(Payments) receipts, net     (9)  
Non-cash activity     (81)  
Restructuring reserve, ending balance 861   861  
Restructuring Program, 2024        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     564  
Expenses 88 $ 279 323 $ 701
(Payments) receipts, net     (239)  
Non-cash activity     (149)  
Restructuring reserve, ending balance 499   499  
Accelerated Depreciation        
Restructuring Reserve [Roll Forward]        
Expenses 56   152  
Accelerated Depreciation | Restructuring Program, 2025        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 0   0  
(Payments) receipts, net     0  
Non-cash activity     0  
Restructuring reserve, ending balance 0   0  
Accelerated Depreciation | Restructuring Program, 2024        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 56 40 152 171
(Payments) receipts, net     0  
Non-cash activity     (152)  
Restructuring reserve, ending balance 0   0  
Separation Costs        
Restructuring Reserve [Roll Forward]        
Expenses 6   494  
Separation Costs | Restructuring Program, 2025        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 0   481  
(Payments) receipts, net     (7)  
Non-cash activity     0  
Restructuring reserve, ending balance 474   474  
Separation Costs | Restructuring Program, 2024        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     564  
Expenses 6 11 13 122
(Payments) receipts, net     (78)  
Non-cash activity     0  
Restructuring reserve, ending balance 499   499  
Other Exit Costs        
Restructuring Reserve [Roll Forward]        
Expenses 328   628  
Other Exit Costs | Restructuring Program, 2025        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 302   470  
(Payments) receipts, net     (2)  
Non-cash activity     (81)  
Restructuring reserve, ending balance 387   387  
Other Exit Costs | Restructuring Program, 2024        
Restructuring Reserve [Roll Forward]        
Restructuring reserve, beginning balance     0  
Expenses 26 $ 228 158 $ 408
(Payments) receipts, net     (161)  
Non-cash activity     3  
Restructuring reserve, ending balance $ 0   $ 0  
v3.25.3
Financial Instruments - Narrative (Details)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
USD ($)
interest_rate_swap
Dec. 31, 2024
USD ($)
Sep. 30, 2024
USD ($)
Sep. 30, 2025
USD ($)
interest_rate_swap
Sep. 30, 2024
USD ($)
Derivative [Line Items]          
Pretax net unrealized loss on derivatives maturing within the next 12 months estimated to be reclassified from AOCI to sales $ 298     $ 298  
Equity investments without readily determinable fair values 834   $ 848 834 $ 848
Unrealized gains recognized on investments in equity securities without readily determinable fair value       1 12
Unrealized losses recognized on investments in equity securities without readily determinable fair values       33 25
Cumulative unrealized gains on investments 293     293  
Cumulative unrealized losses on investments 131     131  
(Income) loss from investments in equity securities, net (373)   31 (563) (169)
Fair value of loans payable and long-term debt, including current portion 37,700 $ 32,600   37,700  
Debt, carrying amount 41,400 37,100   41,400  
Factored accounts receivable 1,700 2,100      
Cash collateral received from counterparties 1 165   1  
Cash collateral advanced to counterparties 0 0   0  
Derivative, notional amount 42,872 38,560   42,872  
Accounts Receivable Factoring Collections          
Derivative [Line Items]          
Restricted cash 35 55   35  
Level 2          
Derivative [Line Items]          
Cash equivalents 17,500 12,300   17,500  
Equity Funds          
Derivative [Line Items]          
Publicly traded equity securities 226   328 226 328
(Income) loss from investments in equity securities, net $ 2   $ (21) $ 53 $ (26)
Interest rate swap contracts          
Derivative [Line Items]          
Number of Interest Rate Swaps Held | interest_rate_swap 7     7  
Derivatives Designated as Hedging Instruments          
Derivative [Line Items]          
Derivative, notional amount $ 14,399 12,465   $ 14,399  
Derivatives Not Designated as Hedging Instruments          
Derivative [Line Items]          
Derivative, notional amount $ 28,473 $ 26,095   $ 28,473  
Maximum | Derivatives Designated as Hedging Instruments          
Derivative [Line Items]          
Maximum average period of maturities of contracts in years (less than)       2 years  
Maximum | Derivatives Not Designated as Hedging Instruments          
Derivative [Line Items]          
Maximum average period of maturities of contracts in years (less than)       6 months  
v3.25.3
Financial Instruments - Schedule of Effect of Net Investment Hedges (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Foreign exchange contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income $ (20) $ 1 $ 45 $ 4
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 3 0 11 2
Euro-denominated notes        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income (1) 169 540 73
Euro-denominated notes | Other (income) expense, net        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Pretax Gain Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing $ 0 $ 0 $ 0 $ 0
v3.25.3
Financial Instruments - Schedule of Interest Rate Swaps Held (Details)
Sep. 30, 2025
USD ($)
interest_rate_swap
Dec. 31, 2024
USD ($)
Derivative [Line Items]    
U.S dollar notional amount $ 42,872,000,000 $ 38,560,000,000
4.50% note due 2033 | 4.50% note due 2033    
Derivative [Line Items]    
Stated interest rate 4.50%  
5.00% note due 2053 | 5.00% note due 2053    
Derivative [Line Items]    
Stated interest rate 5.00%  
Interest rate swap contracts    
Derivative [Line Items]    
Number of Interest Rate Swaps Held | interest_rate_swap 7  
Interest rate swap contracts | 4.50% note due 2033    
Derivative [Line Items]    
Par Value of Debt $ 1,500,000,000  
Number of Interest Rate Swaps Held | interest_rate_swap 6  
U.S dollar notional amount $ 1,500,000,000  
Interest rate swap contracts | 5.00% note due 2053    
Derivative [Line Items]    
Par Value of Debt $ 1,500,000,000  
Number of Interest Rate Swaps Held | interest_rate_swap 1  
U.S dollar notional amount $ 250,000,000  
v3.25.3
Financial Instruments - Schedule of Amounts Recorded on Balance Sheet Related to Fair Value Hedges (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Hedged Liability, Statement of Financial Position [Extensible Enumeration] Long-Term Debt Long-Term Debt
Carrying Amount of Hedged Liabilities $ 1,819 $ 1,509
Cumulative Amount of Fair Value Hedging Adjustment Increase Included in the Carrying Amount $ 80 $ 17
v3.25.3
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
Sep. 30, 2025
Dec. 31, 2024
Derivatives, Fair Value [Line Items]    
Fair value of derivative, asset $ 316 $ 729
Fair value of derivative, liability 492 345
U.S dollar notional amount 42,872 38,560
Derivatives Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Fair value of derivative, asset 172 406
Fair value of derivative, liability 246 2
U.S dollar notional amount 14,399 12,465
Derivatives Not Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Fair value of derivative, asset 144 323
Fair value of derivative, liability 246 343
U.S dollar notional amount $ 28,473 $ 26,095
Interest rate swap contracts | Derivatives Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other Assets Other Assets
Fair value of derivative, asset $ 80 $ 17
Derivative asset, notional amount $ 1,750 $ 1,500
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other Assets    
Derivatives, Fair Value [Line Items]    
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other Assets Other Assets
Fair value of derivative, asset $ 37 $ 66
Derivative asset, notional amount $ 2,274 $ 2,125
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other current assets    
Derivatives, Fair Value [Line Items]    
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other current assets Other current assets
Fair value of derivative, asset $ 55 $ 323
Derivative asset, notional amount $ 4,681 $ 8,662
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Accrued and other current liabilities    
Derivatives, Fair Value [Line Items]    
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Accrued and other current liabilities Accrued and other current liabilities
Fair value of derivative, liability $ 246 $ 1
Derivative liability, notional amount $ 5,694 $ 162
Foreign exchange contracts | Derivatives Designated as Hedging Instruments | Other Noncurrent Liabilities    
Derivatives, Fair Value [Line Items]    
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Other Noncurrent Liabilities Other Noncurrent Liabilities
Fair value of derivative, liability $ 0 $ 1
Derivative liability, notional amount $ 0 $ 16
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 $ 144 $ 323
Derivative asset, notional amount $ 12,498 $ 12,544
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Accrued and other current liabilities Accrued and other current liabilities
Fair value of derivative, liability $ 246 $ 343
Derivative liability, notional amount $ 15,975 $ 13,551
v3.25.3
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
Sep. 30, 2025
Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Gross amounts recognized in the consolidated balance sheet, asset $ 316 $ 729
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, asset (246) (299)
Cash collateral received, asset (1) (165)
Net amounts, asset 69 265
Gross amounts recognized in the consolidated balance sheet, liability 492 345
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, liability (246) (299)
Cash collateral received, liability 0 0
Net amounts, liability $ 246 $ 46
v3.25.3
Financial Instruments - Schedule of Location and Amount of Pretax (Gains) Losses of Derivatives (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Derivative Instruments, Gain (Loss) [Line Items]        
Sales $ 17,276 $ 16,657 $ 48,611 $ 48,544
Other (income) expense, net (238) (162) (281) (151)
Other comprehensive income (loss) 219 (10) (257) (210)
Interest rate swap contracts | Other (income) expense, net        
Derivative Instruments, Gain (Loss) [Line Items]        
Hedged items 4 68 62 42
Derivatives designated as hedging instruments (5) (69) (63) (43)
Foreign exchange contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of gain (loss) recognized in OCI on derivatives 113 (325) (630) 22
(Decrease) increase in Sales as a result of AOCL reclassifications 85 (48) 35 (146)
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 (85) $ 48 (35) 146
Interest rate contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of gain (loss) recognized in OCI on derivatives $ 18   17 (1)
Amount of gain recognized in Other (income) expense, net on derivatives     $ (1) $ (1)
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]     Other (income) expense, net Other (income) expense, net
v3.25.3
Financial Instruments - Schedule of Income Statement Effects on Derivatives Not Designated as Hedging Instruments (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Currency Swap | Other (income) expense, net        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Derivative Pretax Loss (Gain) Recognized in Income $ 39 $ (139) $ (217) $ (65)
Foreign Exchange Future | Sales        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Derivative Pretax Loss (Gain) Recognized in Income $ (8) $ 10 $ 26 $ (10)
v3.25.3
Financial Instruments - Schedule of Information on Available-for-sale Investments (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]          
Amortized Cost $ 145   $ 145   $ 536
Debt securities, unrealized gains 0   0   0
Debt securities, unrealized losses 0   0   0
Debt securities, fair value 145   145   536
Publicly traded equity securities, fair value 1,546   1,546   920
Total debt and publicly traded equity securities, fair value 1,691   1,691   1,456
Unrealized net gains (losses) 367 $ (42) 630 $ 82  
U.S. government and agency securities          
Debt Securities, Available-for-sale [Line Items]          
Amortized Cost 99   99   188
Debt securities, unrealized gains 0   0   0
Debt securities, unrealized losses 0   0   0
Debt securities, fair value 99   99   188
Commercial paper          
Debt Securities, Available-for-sale [Line Items]          
Amortized Cost 45   45   348
Debt securities, unrealized gains 0   0   0
Debt securities, unrealized losses 0   0   0
Debt securities, fair value 45   45   348
Foreign government bonds          
Debt Securities, Available-for-sale [Line Items]          
Amortized Cost 1   1   0
Debt securities, unrealized gains 0   0   0
Debt securities, unrealized losses 0   0   0
Debt securities, fair value $ 1   $ 1   $ 0
v3.25.3
Financial Instruments - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Sep. 30, 2024
Dec. 31, 2023
Assets        
Commercial paper $ 145 $ 536    
Publicly traded equity securities 1,546 920    
Other Assets 18,333 16,044    
Fair value of derivative, asset 316 729    
Liabilities        
Contingent consideration 0 193 $ 208 $ 354
Fair value of derivative, liability 492 345    
Commercial paper        
Assets        
Commercial paper 45 348    
Foreign government bonds        
Assets        
Commercial paper 1 0    
U.S. government and agency securities        
Assets        
Commercial paper 99 188    
Fair Value, Measurements, Recurring        
Assets        
Investments 1,162 910    
Other Assets 529 546    
Fair value of derivative, asset 316 729    
Total assets 2,007 2,185    
Liabilities        
Contingent consideration 0 193    
Fair value of derivative, liability 492 345    
Total liabilities 492 538    
Fair Value, Measurements, Recurring | Foreign exchange contracts        
Assets        
Fair value of derivative, asset 169 499    
Liabilities        
Fair value of derivative, liability 461 338    
Fair Value, Measurements, Recurring | Interest rate swap contracts        
Assets        
Fair value of derivative, asset 80 17    
Fair Value, Measurements, Recurring | Currency options        
Assets        
Fair value of derivative, asset 67 213    
Liabilities        
Fair value of derivative, liability 31 7    
Fair Value, Measurements, Recurring | Level 1        
Assets        
Investments 1,116 463    
Other Assets 529 546    
Fair value of derivative, asset 0 0    
Total assets 1,645 1,009    
Liabilities        
Contingent consideration 0 0    
Fair value of derivative, liability 0 0    
Total liabilities 0 0    
Fair Value, Measurements, Recurring | Level 1 | Foreign exchange contracts        
Assets        
Fair value of derivative, asset 0 0    
Liabilities        
Fair value of derivative, liability 0 0    
Fair Value, Measurements, Recurring | Level 1 | Interest rate swap contracts        
Assets        
Fair value of derivative, asset 0 0    
Fair Value, Measurements, Recurring | Level 1 | Currency options        
Assets        
Fair value of derivative, asset 0 0    
Liabilities        
Fair value of derivative, liability 0 0    
Fair Value, Measurements, Recurring | Level 2        
Assets        
Investments 46 447    
Other Assets 0 0    
Fair value of derivative, asset 316 729    
Total assets 362 1,176    
Liabilities        
Contingent consideration 0 0    
Fair value of derivative, liability 492 345    
Total liabilities 492 345    
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange contracts        
Assets        
Fair value of derivative, asset 169 499    
Liabilities        
Fair value of derivative, liability 461 338    
Fair Value, Measurements, Recurring | Level 2 | Interest rate swap contracts        
Assets        
Fair value of derivative, asset 80 17    
Fair Value, Measurements, Recurring | Level 2 | Currency options        
Assets        
Fair value of derivative, asset 67 213    
Liabilities        
Fair value of derivative, liability 31 7    
Fair Value, Measurements, Recurring | Level 3        
Assets        
Investments 0 0    
Other Assets 0 0    
Fair value of derivative, asset 0 0    
Total assets 0 0    
Liabilities        
Contingent consideration 0 193    
Fair value of derivative, liability 0 0    
Total liabilities 0 193    
Fair Value, Measurements, Recurring | Level 3 | Foreign exchange contracts        
Assets        
Fair value of derivative, asset 0 0    
Liabilities        
Fair value of derivative, liability 0 0    
Fair Value, Measurements, Recurring | Level 3 | Interest rate swap contracts        
Assets        
Fair value of derivative, asset 0 0    
Fair Value, Measurements, Recurring | Level 3 | Currency options        
Assets        
Fair value of derivative, asset 0 0    
Liabilities        
Fair value of derivative, liability 0 0    
Fair Value, Measurements, Recurring | Commercial paper        
Assets        
Commercial paper 45 348    
Fair Value, Measurements, Recurring | Commercial paper | Level 1        
Assets        
Commercial paper 0 0    
Fair Value, Measurements, Recurring | Commercial paper | Level 2        
Assets        
Commercial paper 45 348    
Fair Value, Measurements, Recurring | Commercial paper | Level 3        
Assets        
Commercial paper 0 0    
Fair Value, Measurements, Recurring | Foreign government bonds        
Assets        
U.S. government and agency securities 1 0    
Fair Value, Measurements, Recurring | Foreign government bonds | Level 1        
Assets        
U.S. government and agency securities 0 0    
Fair Value, Measurements, Recurring | Foreign government bonds | Level 2        
Assets        
U.S. government and agency securities 1 0    
Fair Value, Measurements, Recurring | Foreign government bonds | Level 3        
Assets        
U.S. government and agency securities 0 0    
Fair Value, Measurements, Recurring | U.S. government and agency securities        
Assets        
U.S. government and agency securities 0 99    
U.S. government and agency securities 99 89    
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 1        
Assets        
U.S. government and agency securities 0 0    
U.S. government and agency securities 99 89    
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 2        
Assets        
U.S. government and agency securities 0 99    
U.S. government and agency securities 0 0    
Fair Value, Measurements, Recurring | U.S. government and agency securities | Level 3        
Assets        
U.S. government and agency securities 0 0    
U.S. government and agency securities 0 0    
Fair Value, Measurements, Recurring | Publicly traded equity securities        
Assets        
Publicly traded equity securities 1,116 463    
Publicly traded equity securities 430 457    
Fair Value, Measurements, Recurring | Publicly traded equity securities | Level 1        
Assets        
Publicly traded equity securities 1,116 463    
Publicly traded equity securities 430 457    
Liabilities        
Securities subject to contractual sale restrictions   81    
Fair Value, Measurements, Recurring | Publicly traded equity securities | Level 2        
Assets        
Publicly traded equity securities 0 0    
Publicly traded equity securities 0 0    
Fair Value, Measurements, Recurring | Publicly traded equity securities | Level 3        
Assets        
Publicly traded equity securities 0 0    
Publicly traded equity securities $ 0 $ 0    
v3.25.3
Financial Instruments - Schedule of Information About Changes in Liabilities for Contingent Consideration (Details) - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Fair value, beginning balance $ 193 $ 354
Changes in estimated fair value (52) 2
Payments (141) (148)
Fair value, ending balance 0 $ 208
Zerbaxa    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Changes in estimated fair value (45)  
Payments $ (25)  
v3.25.3
Inventories - Schedule of Inventories (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Inventory Disclosure [Abstract]    
Finished goods $ 2,249 $ 2,022
Raw materials and work in process 10,165 8,831
Supplies 325 289
Total 12,739 11,142
Decrease to LIFO cost (883) (840)
Total current and noncurrent inventories 11,856 10,302
Recognized as:    
Inventories 6,444 6,109
Other Assets $ 5,412 $ 4,193
v3.25.3
Inventories - Narrative (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Inventory [Line Items]    
Inventories classified in other assets $ 5,412 $ 4,193
Inventories Not Expected to be Sold Within One Year    
Inventory [Line Items]    
Inventories classified in other assets 5,200 3,800
Inventories Produced in Preparation for Product Launches    
Inventory [Line Items]    
Inventories classified in other assets $ 167 $ 412
v3.25.3
Long-Term Debt (Details) - USD ($)
$ in Millions
1 Months Ended
Oct. 31, 2025
Sep. 30, 2025
Verona Pharma plc | Subsequent Event    
Debt Instrument [Line Items]    
Consideration transferred, asset acquisition $ 10,500  
Senior Notes    
Debt Instrument [Line Items]    
Face amount of debt   $ 6,000
Floating Rate Notes Due 2027 | Senior Notes    
Debt Instrument [Line Items]    
Face amount of debt   500
3.85% notes due 2027 | Senior Notes    
Debt Instrument [Line Items]    
Face amount of debt   $ 750
Stated interest rate   3.85%
4.15% notes due 2030 | Senior Notes    
Debt Instrument [Line Items]    
Face amount of debt   $ 750
Stated interest rate   4.15%
4.55% notes due 2032 | Senior Notes    
Debt Instrument [Line Items]    
Face amount of debt   $ 1,000
Stated interest rate   4.55%
4.95% notes due 2035 | Senior Notes    
Debt Instrument [Line Items]    
Face amount of debt   $ 1,750
Stated interest rate   4.95%
5.70% notes due 2055 | Senior Notes    
Debt Instrument [Line Items]    
Face amount of debt   $ 1,250
Stated interest rate   5.70%
v3.25.3
Contingencies (Details)
$ in Millions
1 Months Ended 2 Months Ended 5 Months Ended 9 Months Ended
Apr. 24, 2025
patent
Mar. 13, 2025
Nov. 30, 2025
patent
Dec. 31, 2023
case
Jul. 31, 2023
motion
Jun. 30, 2023
May 31, 2023
patent
Oct. 31, 2025
patent
interest_rate_swap
Oct. 31, 2024
patent
Sep. 30, 2025
USD ($)
case
plaintiff
company
Sep. 19, 2025
Jul. 11, 2025
plaintiff
Jun. 02, 2025
patent
May 01, 2025
plaintiff
Apr. 07, 2025
Mar. 21, 2025
plaintiff
Mar. 11, 2025
case
Dec. 31, 2024
USD ($)
Loss Contingencies [Line Items]                                    
Number of plaintiffs in complaint | plaintiff                       6   6,000,000   7,000,000    
Loss contingency, joint stipulation response period                     15 days       14 days      
Legal Defense Costs                                    
Loss Contingencies [Line Items]                                    
Legal defense costs reserve | $                   $ 220               $ 225
Pending Litigation | Commercial and Other Litigation                                    
Loss Contingencies [Line Items]                                    
Loss contingency, pending claims | plaintiff                   2                
Loss contingency, number of plaintiffs | plaintiff                   2                
Pending Litigation | Patents - PGR Petition                                    
Loss Contingencies [Line Items]                                    
Loss contingency, number of patents allegedly infringed 12                                  
U.S. | Settled Litigation | Qui Tam                                    
Loss Contingencies [Line Items]                                    
Loss contingency, new claims filed, number | motion         2                          
Dr. Scholl's | U.S. | Pending Litigation                                    
Loss Contingencies [Line Items]                                    
Loss contingency, pending claims | case                   605                
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                
Zetia | U.S. | Pending Litigation                                    
Loss Contingencies [Line Items]                                    
Loss contingency, number of cases remanded | case       4,000,000                            
Bridion | Patents                                    
Loss Contingencies [Line Items]                                    
Loss contingency, claims settled, number of companies | company                   5                
Bridion | Settled Litigation | Patents                                    
Loss Contingencies [Line Items]                                    
Patent extension, term   5 years       5 years                        
Pediatric exclusivity, term   6 months                                
Januvia, Janumet, Janumet XR | Settled Litigation                                    
Loss Contingencies [Line Items]                                    
Loss contingency, companies settled with, minimum number | company                   24                
Keytruda | Patents | Subsequent Event                                    
Loss Contingencies [Line Items]                                    
Loss contingency, number of appeals issued               2                    
Loss contingency, number of possible appeals | interest_rate_swap               4                    
Keytruda | Patents | Forecast                                    
Loss Contingencies [Line Items]                                    
Loss contingency, number of patents allegedly infringed     3                              
Keytruda | Pending Litigation | Patents                                    
Loss Contingencies [Line Items]                                    
Loss contingency, number of patents allegedly infringed             9   9                  
Keytruda | Pending Litigation | Patents | Subsequent Event                                    
Loss Contingencies [Line Items]                                    
Number of additional patents unpatentable               6                    
Subcutaneous Pembrolizumab | Pending Litigation | Patents                                    
Loss Contingencies [Line Items]                                    
Loss contingency, pending claims                         3          
Loss contingency, number of patents allegedly infringed 15                                  
Subcutaneous Pembrolizumab | Pending Litigation | Patents - PGR Petition                                    
Loss Contingencies [Line Items]                                    
Loss contingency, pending claims                         10          
Subcutaneous Pembrolizumab | Pending Litigation | PGR Petition Process, Ineligible to be Challenged                                    
Loss Contingencies [Line Items]                                    
Loss contingency, pending claims 3                                  
v3.25.3
Equity (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Common stock, beginning balance (in shares)     3,577,103,522  
Equity, beginning balance $ 49,060 $ 43,648 $ 46,372 $ 37,635
Treasury stock, beginning balance (in shares)     1,049,466,187  
Net income attributable to Merck & Co., Inc. 5,785 3,157 $ 15,291 13,374
Other comprehensive loss, net of taxes 219 (10) (257) (210)
Cash dividends declared on common stock (2,031) (1,960) (6,129) (5,885)
Treasury stock shares purchased (1,324) (444) (3,832) (817)
Share-based compensation plans and other 208 177 464 460
Net income attributable to noncontrolling interests 2 4 10 15
Distributions attributable to noncontrolling interests $ (12) (12) $ (12) (12)
Common stock, ending balance (in shares) 3,577,103,522   3,577,103,522  
Equity, ending balance $ 51,907 $ 44,560 $ 51,907 $ 44,560
Treasury stock, ending balance (in shares) 1,089,754,712   1,089,754,712  
Cash dividends declared on common stock (in dollars per share) $ 0.81 $ 0.77 $ 2.43 $ 2.31
  Common Stock        
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Common stock, beginning balance (in shares) 3,577,000,000 3,577,000,000 3,577,000,000 3,577,000,000
Equity, beginning balance $ 1,788 $ 1,788 $ 1,788 $ 1,788
Common stock, ending balance (in shares) 3,577,000,000 3,577,000,000 3,577,000,000 3,577,000,000
Equity, ending balance $ 1,788 $ 1,788 $ 1,788 $ 1,788
Other Paid-In Capital        
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Equity, beginning balance 44,644 44,362 44,704 44,509
Share-based compensation plans and other 188 168 128 21
Equity, ending balance 44,832 44,530 44,832 44,530
Retained Earnings        
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Equity, beginning balance 68,477 60,187 63,069 53,895
Net income attributable to Merck & Co., Inc. 5,785 3,157 15,291 13,374
Cash dividends declared on common stock (2,031) (1,960) (6,129) (5,885)
Equity, ending balance 72,231 61,384 72,231 61,384
Accumulated Other Comprehensive Loss        
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Equity, beginning balance (5,421) (5,361) (4,945) (5,161)
Other comprehensive loss, net of taxes 219 (10) (257) (210)
Equity, ending balance (5,202) (5,371) (5,202) (5,371)
 Treasury Stock        
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Equity, beginning balance $ (60,495) $ (57,394) $ (58,303) $ (57,450)
Treasury stock, beginning balance (in shares) 1,074,000,000 1,041,000,000 1,049,000,000 1,045,000,000
Treasury stock shares purchased (in shares) 16,000,000 4,000,000 46,000,000 7,000,000
Treasury stock shares purchased $ (1,324) $ (444) $ (3,832) $ (817)
Share-based compensation plans and other $ 20 $ 9 $ 336 $ 438
Share-based compensation plans and other (in shares) 0 0 (5,000,000) (7,000,000)
Equity, ending balance $ (61,799) $ (57,829) $ (61,799) $ (57,829)
Treasury stock, ending balance (in shares) 1,090,000,000 1,045,000,000 1,090,000,000 1,045,000,000
Non- controlling Interests        
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Equity, beginning balance $ 67 $ 66 $ 59 $ 54
Share-based compensation plans and other 0     1
Net income attributable to noncontrolling interests 2 4 10 15
Distributions attributable to noncontrolling interests (12) (12) (12) (12)
Equity, ending balance $ 57 $ 58 $ 57 $ 58
v3.25.3
Pension and Other Postretirement Benefit Plans - Schedule of Net Benefit Costs (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Other Postretirement Benefit Plans        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 9 $ 7 $ 29 $ 23
Interest cost 15 14 46 42
Expected return on plan assets (13) (20) (39) (60)
Amortization of unrecognized prior service credit (10) (11) (30) (32)
Net (gain) loss amortization (12) (14) (33) (38)
Net periodic benefit cost (11) (24) (27) (65)
U.S. | Pension Plans        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 100 100 279 273
Interest cost 143 134 425 403
Expected return on plan assets (210) (206) (630) (621)
Amortization of unrecognized prior service credit 0 0 0 0
Net (gain) loss amortization 16 12 42 30
Termination benefits 0 1 1 5
Curtailments 9 0 8 0
Net periodic benefit cost 58 41 125 90
International | Pension Plans        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 57 60 171 182
Interest cost 78 74 225 220
Expected return on plan assets (159) (139) (454) (416)
Amortization of unrecognized prior service credit (4) (3) (12) (10)
Net (gain) loss amortization 3 1 8 4
Termination benefits 0 0 0 0
Curtailments (16) 0 (16) 0
Net periodic benefit cost $ (41) $ (7) $ (78) $ (20)
v3.25.3
Other (Income) Expense, Net - Schedule of Other (Income) Expense, Net (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Other Income and Expenses [Abstract]        
Interest income $ (96) $ (127) $ (274) $ (269)
Interest expense 327 330 946 943
Exchange losses 56 33 224 177
(Income) loss from investments in equity securities, net (373) 31 (563) (169)
Net periodic defined benefit plan (credit) cost other than service cost (152) (157) (452) (476)
Other, net 0 (272) (162) (357)
Other (income) expense, net $ (238) $ (162) $ (281) $ (151)
v3.25.3
Other (Income) Expense, Net - Narrative (Details) - USD ($)
$ in Millions
1 Months Ended 9 Months Ended
Aug. 31, 2024
Sep. 30, 2025
Sep. 30, 2024
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Interest paid   $ 849 $ 822
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Upfront cash payment $ 170    
v3.25.3
Income Taxes (Details) - USD ($)
$ in Millions
1 Months Ended 3 Months Ended 9 Months Ended
Apr. 30, 2025
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]          
Effective income tax rate   14.20% 22.70% 13.30% 15.10%
Income tax rate, unfavorable discrete impact     7.20%   2.10%
Effective income tax rate reconciliation, tax contingency, favorable impact, percent         1.60%
Unrecognized tax benefits         $ 259
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        
v3.25.3
Earnings Per Share - Calculations of Earnings Per Share (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Earnings Per Share [Abstract]        
Net Income Attributable to Merck & Co., Inc., basic $ 5,785 $ 3,157 $ 15,291 $ 13,374
Net Income Attributable to Merck & Co., Inc., diluted $ 5,785 $ 3,157 $ 15,291 $ 13,374
Average common shares outstanding (in shares) 2,495 2,534 2,509 2,534
Common shares issuable (in shares) 3 7 5 9
Average common shares outstanding assuming dilution (in shares) 2,498 2,541 2,514 2,543
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 2.32 $ 1.25 $ 6.09 $ 5.28
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 2.32 $ 1.24 $ 6.08 $ 5.26
v3.25.3
Earnings Per Share - Narrative (Details) - shares
shares in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Earnings Per Share [Abstract]        
Antidilutive shares (in shares) 15 7 12 6
v3.25.3
Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Equity, beginning balance $ 49,060 $ 43,648 $ 46,372 $ 37,635
Other comprehensive income (loss), net of taxes 219 (10) (257) (210)
Equity, ending balance 51,907 44,560 51,907 44,560
Accumulated Other Comprehensive Loss        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Equity, beginning balance (5,421) (5,361) (4,945) (5,161)
Other comprehensive income (loss) before reclassification adjustments, pretax 142 (46) (269) (75)
Tax 16 85 14 (10)
Other comprehensive income (loss) before reclassification adjustments, net of taxes 158 39 (255) (85)
Reclassification adjustments, pretax 81 (63) 12 (171)
Tax (20) 14 (14) 46
Reclassification adjustments, net of taxes 61 (49) (2) (125)
Other comprehensive income (loss), net of taxes 219 (10) (257) (210)
Equity, ending balance (5,202) (5,371) (5,202) (5,371)
Derivatives        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Equity, beginning balance (385) 173 242 (24)
Other comprehensive income (loss) before reclassification adjustments, pretax 113 (325) (630) 22
Tax (24) 68 132 (5)
Other comprehensive income (loss) before reclassification adjustments, net of taxes 89 (257) (498) 17
Reclassification adjustments, pretax 103 (49) 52 (147)
Tax (22) 10 (11) 31
Reclassification adjustments, net of taxes 81 (39) 41 (116)
Other comprehensive income (loss), net of taxes 170 (296) (457) (99)
Equity, ending balance (215) (123) (215) (123)
Employee Benefit Plans        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Equity, beginning balance (2,353) (2,808) (2,327) (2,793)
Other comprehensive income (loss) before reclassification adjustments, pretax 93 0 91 6
Tax 1 (3) 0 (5)
Other comprehensive income (loss) before reclassification adjustments, net of taxes 94 (3) 91 1
Reclassification adjustments, pretax (22) (14) (40) (44)
Tax 2 4 (3) 15
Reclassification adjustments, net of taxes (20) (10) (43) (29)
Other comprehensive income (loss), net of taxes 74 (13) 48 (28)
Equity, ending balance (2,279) (2,821) (2,279) (2,821)
Foreign Currency Translation Adjustment        
Accumulated Other Comprehensive Income (Loss) [Roll Forward]        
Equity, beginning balance (2,683) (2,726) (2,860) (2,344)
Other comprehensive income (loss) before reclassification adjustments, pretax (64) 279 270 (103)
Tax 39 20 (118) 0
Other comprehensive income (loss) before reclassification adjustments, net of taxes (25) 299 152 (103)
Reclassification adjustments, pretax 0 0 0 20
Tax 0 0 0 0
Reclassification adjustments, net of taxes 0 0 0 20
Other comprehensive income (loss), net of taxes (25) 299 152 (83)
Equity, ending balance $ (2,708) $ (2,427) $ (2,708) $ (2,427)
v3.25.3
Segment Reporting - Narrative (Details)
$ in Billions
3 Months Ended 9 Months Ended
Sep. 30, 2025
USD ($)
Sep. 30, 2024
USD ($)
Sep. 30, 2025
USD ($)
segment
Sep. 30, 2024
USD ($)
Segment Reporting [Abstract]        
Number of operating segments | segment     2  
Sales discounts | $ $ 2.6 $ 3.6 $ 7.2 $ 10.1
v3.25.3
Segment Reporting - Schedule of Sales from Products (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Segment Reporting Information [Line Items]        
Sales $ 17,276 $ 16,657 $ 48,611 $ 48,544
Increase in hedge revenue     (61) 156
Revenue related to the sale of the marketing rights     111 91
U.S.        
Segment Reporting Information [Line Items]        
Sales 10,012 8,736 27,371 24,089
Non-US        
Segment Reporting Information [Line Items]        
Sales 7,264 7,922 21,240 24,455
Operating Segments        
Segment Reporting Information [Line Items]        
Sales 17,226 16,430 48,148 47,838
Operating Segments | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 15,611 14,943 43,299 43,358
Operating Segments | Animal Health        
Segment Reporting Information [Line Items]        
Sales 1,615 1,487 4,849 4,480
Operating Segments | U.S.        
Segment Reporting Information [Line Items]        
Sales 9,997 8,714 27,252 23,980
Operating Segments | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 9,493 8,227 25,747 22,563
Operating Segments | U.S. | Animal Health        
Segment Reporting Information [Line Items]        
Sales 504 487 1,505 1,417
Operating Segments | Non-US        
Segment Reporting Information [Line Items]        
Sales 7,230 7,716 20,897 23,858
Operating Segments | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 6,118 6,717 17,552 20,795
Operating Segments | Non-US | Animal Health        
Segment Reporting Information [Line Items]        
Sales 1,112 999 3,345 3,063
Operating Segments | Keytruda | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 8,142 7,429 23,303 21,646
Operating Segments | Keytruda | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 4,879 4,500 13,936 13,031
Operating Segments | Keytruda | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 3,263 2,929 9,367 8,614
Operating Segments | Alliance revenue - Lynparza | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 379 337 1,061 947
Operating Segments | Alliance revenue - Lynparza | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 184 161 503 449
Operating Segments | Alliance revenue - Lynparza | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 195 177 558 498
Operating Segments | Alliance revenue - Lenvima | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 258 251 781 755
Operating Segments | Alliance revenue - Lenvima | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 177 173 545 523
Operating Segments | Alliance revenue - Lenvima | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 81 78 236 233
Operating Segments | Welireg | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 196 139 496 349
Operating Segments | Welireg | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 161 127 422 320
Operating Segments | Welireg | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 35 12 74 29
Operating Segments | Alliance Revenue - Reblozyl | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 136 100 361 261
Operating Segments | Alliance Revenue - Reblozyl | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 111 82 299 215
Operating Segments | Alliance Revenue - Reblozyl | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 25 18 62 45
Operating Segments | Gardasil/Gardasil 9 | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 1,749 2,306 4,202 7,032
Operating Segments | Gardasil/Gardasil 9 | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 1,154 1,020 2,235 2,045
Operating Segments | Gardasil/Gardasil 9 | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 595 1,285 1,967 4,988
Operating Segments | ProQuad/M-M-R II/Varivax | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 684 703 1,832 1,891
Operating Segments | ProQuad/M-M-R II/Varivax | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 554 572 1,457 1,500
Operating Segments | ProQuad/M-M-R II/Varivax | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 130 131 374 391
Operating Segments | Vaxneuvance | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 226 239 685 647
Operating Segments | Vaxneuvance | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 134 137 409 397
Operating Segments | Vaxneuvance | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 91 103 276 251
Operating Segments | RotaTeq | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 204 193 554 572
Operating Segments | RotaTeq | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 141 131 366 388
Operating Segments | RotaTeq | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 63 62 187 185
Operating Segments | Capvaxive | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 244 47 480 47
Operating Segments | Capvaxive | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 238 47 473 47
Operating Segments | Capvaxive | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 7 0 8 0
Operating Segments | Pneumovax 23 | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 45 68 124 188
Operating Segments | Pneumovax 23 | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 10 19 13 36
Operating Segments | Pneumovax 23 | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 35 49 111 152
Operating Segments | Bridion | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 439 420 1,341 1,315
Operating Segments | Bridion | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 392 339 1,181 1,020
Operating Segments | Bridion | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 47 81 161 296
Operating Segments | Prevymis | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 266 208 702 570
Operating Segments | Prevymis | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 128 101 345 265
Operating Segments | Prevymis | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 138 107 357 305
Operating Segments | Zerbaxa | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 81 64 225 182
Operating Segments | Zerbaxa | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 49 39 136 106
Operating Segments | Zerbaxa | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 32 26 89 77
Operating Segments | Dificid | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 43 96 222 261
Operating Segments | Dificid | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 30 83 185 231
Operating Segments | Dificid | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 13 13 37 30
Operating Segments | Winrevair | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 360 149 976 219
Operating Segments | Winrevair | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 335 147 926 216
Operating Segments | Winrevair | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 25 3 49 3
Operating Segments | Alliance revenue - Adempas/Verquvo | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 112 102 340 306
Operating Segments | Alliance revenue - Adempas/Verquvo | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 103 96 308 283
Operating Segments | Alliance revenue - Adempas/Verquvo | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 8 7 32 22
Operating Segments | Adempas | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 82 72 229 214
Operating Segments | Adempas | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 0 0 0
Operating Segments | Adempas | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 82 72 229 214
Operating Segments | Lagevrio | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 138 383 323 843
Operating Segments | Lagevrio | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 24 84 90 144
Operating Segments | Lagevrio | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 114 299 233 699
Operating Segments | Isentress/Isentress HD | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 82 102 258 302
Operating Segments | Isentress/Isentress HD | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 44 54 144 147
Operating Segments | Isentress/Isentress HD | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 37 48 114 155
Operating Segments | Delstrigo | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 77 65 228 180
Operating Segments | Delstrigo | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 13 15 42 42
Operating Segments | Delstrigo | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 64 50 185 139
Operating Segments | Pifeltro | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 43 42 128 123
Operating Segments | Pifeltro | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 29 31 86 86
Operating Segments | Pifeltro | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 14 12 43 37
Operating Segments | Belsomra | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 47 78 137 177
Operating Segments | Belsomra | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 28 20 59 53
Operating Segments | Belsomra | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 19 58 77 124
Operating Segments | Simponi | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 189 0 545
Operating Segments | Simponi | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 0 0 0
Operating Segments | Simponi | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 189 0 545
Operating Segments | Remicade | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 41 0 115
Operating Segments | Remicade | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 0 0 0
Operating Segments | Remicade | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 0 41 0 115
Operating Segments | Januvia | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 382 278 1,302 1,102
Operating Segments | Januvia | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 258 67 819 428
Operating Segments | Januvia | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 124 211 483 674
Operating Segments | Janumet | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 243 204 741 679
Operating Segments | Janumet | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 78 15 210 70
Operating Segments | Janumet | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 165 190 530 610
Operating Segments | Other pharmaceutical | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 953 638 2,268 1,890
Operating Segments | Other pharmaceutical | U.S. | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 239 167 558 521
Operating Segments | Other pharmaceutical | Non-US | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 716 466 1,713 1,364
Operating Segments | Livestock | Animal Health        
Segment Reporting Information [Line Items]        
Sales 1,023 886 2,909 2,573
Operating Segments | Livestock | U.S. | Animal Health        
Segment Reporting Information [Line Items]        
Sales 213 194 598 529
Operating Segments | Livestock | Non-US | Animal Health        
Segment Reporting Information [Line Items]        
Sales 811 692 2,312 2,044
Operating Segments | Companion Animal | Animal Health        
Segment Reporting Information [Line Items]        
Sales 592 601 1,940 1,907
Operating Segments | Companion Animal | U.S. | Animal Health        
Segment Reporting Information [Line Items]        
Sales 291 293 907 888
Operating Segments | Companion Animal | Non-US | Animal Health        
Segment Reporting Information [Line Items]        
Sales 301 307 1,033 1,019
Operating Segments | Alliance revenue - Koselugo | Pharmaceutical        
Segment Reporting Information [Line Items]        
Sales 214 39 301 114
Corporate, Non-Segment        
Segment Reporting Information [Line Items]        
Sales 50 227 463 706
Corporate, Non-Segment | U.S.        
Segment Reporting Information [Line Items]        
Sales 15 22 119 109
Corporate, Non-Segment | Non-US        
Segment Reporting Information [Line Items]        
Sales $ 34 $ 206 $ 343 $ 597
v3.25.3
Segment Reporting - Schedule of Consolidated Sales by Geographic Area (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Revenue from External Customer [Line Items]        
Sales $ 17,276 $ 16,657 $ 48,611 $ 48,544
United States        
Revenue from External Customer [Line Items]        
Sales 10,012 8,736 27,371 24,089
Europe, Middle East and Africa        
Revenue from External Customer [Line Items]        
Sales 3,680 3,583 10,789 10,661
Latin America        
Revenue from External Customer [Line Items]        
Sales 905 936 2,556 2,591
Asia Pacific (other than China and Japan)        
Revenue from External Customer [Line Items]        
Sales 764 823 2,238 2,294
Japan        
Revenue from External Customer [Line Items]        
Sales 712 938 2,007 2,445
China        
Revenue from External Customer [Line Items]        
Sales 405 1,017 1,553 4,606
Other        
Revenue from External Customer [Line Items]        
Sales $ 798 $ 624 $ 2,097 $ 1,858
v3.25.3
Segment Reporting - Schedule of Reconciliation of Segment Profits to Income before Taxes (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Segment Reporting Information [Line Items]        
Sales $ 17,276 $ 16,657 $ 48,611 $ 48,544
Less segment costs:        
Cost of sales 3,855 4,080 10,831 11,365
Selling, general and administrative 2,633 2,731 7,835 7,952
Research and development (4,234) (5,862) (11,903) (13,354)
Other segment items 238 162 281 151
Total segment profits 6,745 4,090 17,647 15,766
Other profits 6,745 4,090 17,647 15,766
Unallocated:        
Interest income 96 127 274 269
Interest expense (327) (330) (946) (943)
Amortization     (1,820) (1,720)
Depreciation     (1,552) (1,582)
Research and development (4,234) (5,862) (11,903) (13,354)
Restructuring costs (47) (56) (676) (258)
Total segment profits        
Segment Reporting Information [Line Items]        
Sales 17,226 16,430 48,148 47,838
Less segment costs:        
Total segment profits 13,049 12,057 36,001 35,225
Other profits 13,049 12,057 36,001 35,225
Unallocated:        
Depreciation (83) (86) (207) (214)
Total segment profits | Pharma- ceutical        
Segment Reporting Information [Line Items]        
Sales 15,611 14,943 43,299 43,358
Less segment costs:        
Cost of sales 1,664 1,904 4,838 5,319
Selling, general and administrative 1,469 1,519 4,327 4,462
Research and development 0 0 0 0
Other segment items (60) (27) (130) (74)
Total segment profits 12,538 11,547 34,264 33,651
Other profits 12,538 11,547 34,264 33,651
Unallocated:        
Depreciation (1) (1) (4) (3)
Research and development 0 0 0 0
Total segment profits | Animal Health        
Segment Reporting Information [Line Items]        
Sales 1,615 1,487 4,849 4,480
Less segment costs:        
Cost of sales 710 613 1,968 1,838
Selling, general and administrative 277 268 822 791
Research and development (118) (95) (323) (276)
Other segment items (1) 1 (1) 1
Total segment profits 511 510 1,737 1,574
Other profits 511 510 1,737 1,574
Unallocated:        
Depreciation (82) (85) (203) (211)
Research and development (118) (95) (323) (276)
Other profits        
Segment Reporting Information [Line Items]        
Sales 50 227 463 706
Less segment costs:        
Research and development (3,839) (5,716) (11,159) (12,926)
Total segment profits 4 117 235 391
Other profits 4 117 235 391
Unallocated:        
Interest income 96 127 274 269
Interest expense (327) (330) (946) (943)
Amortization (623) (633) (1,820) (1,720)
Depreciation (449) (467) (1,345) (1,368)
Research and development (3,839) (5,716) (11,159) (12,926)
Restructuring costs (47) (56) (676) (258)
Other unallocated, net $ (1,119) $ (1,009) $ (2,917) $ (2,904)
v3.25.3
Segment Reporting - Schedule of Equity Income from Affiliates and Depreciation Included in Segment Profits (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Segment Reporting Information [Line Items]        
Depreciation     $ 1,552 $ 1,582
Operating Segments        
Segment Reporting Information [Line Items]        
Equity income from affiliates $ 62 $ 43 148 121
Depreciation 83 86 207 214
Operating Segments | Pharma- ceutical        
Segment Reporting Information [Line Items]        
Equity income from affiliates 62 43 148 121
Depreciation 1 1 4 3
Operating Segments | Animal Health        
Segment Reporting Information [Line Items]        
Equity income from affiliates 0 0 0 0
Depreciation $ 82 $ 85 $ 203 $ 211
v3.25.3
Segment Reporting - Schedule of Property, Plant and Equipment, Net by Geographic Area (Details) - USD ($)
$ in Millions
Sep. 30, 2025
Dec. 31, 2024
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net $ 25,639 $ 23,779
U.S.    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 15,482 14,724
Europe, Middle East and Africa    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 8,665 7,548
Asia Pacific (other than China and Japan)    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 948 982
China    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 208 202
Japan    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 147 143
Latin America    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net 139 133
Other    
Revenues from External Customers and Long-Lived Assets [Line Items]    
Property, plant and equipment, net $ 50 $ 47