MERCK & CO., INC., 10-K filed on 2/24/2026
Annual Report
v3.25.4
Cover Page - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Jan. 31, 2026
Jun. 30, 2025
Document Information [Line Items]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2025    
Current Fiscal Year End Date --12-31    
Document Transition Report false    
Entity File Number 1-6571    
Entity Registrant Name Merck & Co., Inc.    
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 Incorporation, State or Country Code NJ    
Entity Tax Identification Number 22-1918501    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
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    
ICFR Auditor Attestation Flag true    
Document Financial Statement Error Correction [Flag] false    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding   2,472,392,003  
Entity Public Float     $ 198,051
Documents Incorporated by Reference
Proxy Statement for the Annual Meeting of Shareholders to be held May 26, 2026, to be filed with the
Securities and Exchange Commission within 120 days after the close of the fiscal year covered by this report
   
Amendment Flag false    
Document Fiscal Year Focus 2025    
Document Fiscal Period Focus FY    
Entity Central Index Key 0000310158    
Common Stock ($0.50 par value)      
Document Information [Line Items]      
Title of 12(b) Security Common Stock ($0.50 par value)    
Trading Symbol MRK    
Security Exchange Name NYSE    
1.875% Notes due 2026      
Document Information [Line Items]      
Title of 12(b) Security 1.875% Notes due 2026    
Trading Symbol MRK/26    
Security Exchange Name NYSE    
3.250% Notes due 2032      
Document Information [Line Items]      
Title of 12(b) Security 3.250% Notes due 2032    
Trading Symbol MRK/32    
Security Exchange Name NYSE    
2.500% Notes due 2034      
Document Information [Line Items]      
Title of 12(b) Security 2.500% Notes due 2034    
Trading Symbol MRK/34    
Security Exchange Name NYSE    
1.375% Notes due 2036      
Document Information [Line Items]      
Title of 12(b) Security 1.375% Notes due 2036    
Trading Symbol MRK 36A    
Security Exchange Name NYSE    
3.500% Notes due 2037      
Document Information [Line Items]      
Title of 12(b) Security 3.500% Notes due 2037    
Trading Symbol MRK/37    
Security Exchange Name NYSE    
3.700% Notes due 2044      
Document Information [Line Items]      
Title of 12(b) Security 3.700% Notes due 2044    
Trading Symbol MRK/44    
Security Exchange Name NYSE    
3.750% Notes due 2054      
Document Information [Line Items]      
Title of 12(b) Security 3.750% Notes due 2054    
Trading Symbol MRK/54    
Security Exchange Name NYSE    
v3.25.4
Audit Information
12 Months Ended
Dec. 31, 2025
Audit Information [Abstract]  
Auditor Name PricewaterhouseCoopers LLP
Auditor Location Florham Park, New Jersey
Auditor Firm ID 238
v3.25.4
Consolidated Statement of Income - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Income Statement [Abstract]      
Sales $ 65,011 $ 64,168 $ 60,115
Costs, Expenses and Other      
Cost of sales 16,382 15,193 16,126
Selling, general and administrative 10,733 10,816 10,504
Research and development 15,789 17,938 30,531
Restructuring costs 889 309 599
Other (income) expense, net 151 (24) 466
Total costs, expenses and other 43,944 44,232 58,226
Income Before Taxes 21,067 19,936 1,889
Taxes on Income 2,804 2,803 1,512
Net Income 18,263 17,133 377
Less: Net Income Attributable to Noncontrolling Interests 9 16 12
Net Income Attributable to Merck & Co., Inc. $ 18,254 $ 17,117 $ 365
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 7.30 $ 6.76 $ 0.14
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 7.28 $ 6.74 $ 0.14
v3.25.4
Consolidated Statement of Comprehensive Income (Loss) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Statement of Comprehensive Income [Abstract]      
Net Income Attributable to Merck & Co., Inc. $ 18,254 $ 17,117 $ 365
Other Comprehensive Income (Loss) Net of Taxes:      
Net unrealized (loss) income on derivatives, net of reclassifications (347) 266 (97)
Benefit plan net gain (loss) and prior service credit (cost), net of amortization 828 466 (385)
Cumulative translation adjustment 177 (516) 89
Other comprehensive income (loss), net of taxes 658 216 (393)
Comprehensive Income (Loss) Attributable to Merck & Co., Inc. $ 18,912 $ 17,333 $ (28)
v3.25.4
Consolidated Balance Sheet - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Current Assets    
Cash and cash equivalents $ 14,565 $ 13,242
Short-term investments 0 447
Accounts receivable (net of allowance for doubtful accounts of $97 in 2025 and $89 in 2024) 11,775 10,278
Inventories (excludes inventories of $5,681 in 2025 and $4,193 in 2024 classified in Other assets - see Note 7) 6,658 6,109
Other current assets 10,518 8,706
Total current assets 43,516 38,782
Investments 956 463
Property, Plant and Equipment (at cost)    
Land 321 307
Buildings 17,983 16,360
Machinery, equipment and office furnishings 19,760 18,283
Construction in progress 9,166 7,984
Property, plant and equipment (at cost) 47,230 42,934
Less: accumulated depreciation 21,914 19,155
Property, plant and equipment, net 25,316 23,779
Goodwill 21,579 21,668
Other Intangibles, Net 26,681 16,370
Other Assets 18,818 16,044
Total Assets 136,866 117,106
Current Liabilities    
Loans payable and current portion of long-term debt 2,589 2,649
Trade accounts payable 4,404 4,079
Accrued and other current liabilities 14,468 15,694
Income taxes payable 4,726 3,914
Dividends payable 2,140 2,084
Total current liabilities 28,327 28,420
Long-Term Debt 46,750 34,462
Deferred Income Taxes 1,439 1,387
Other Noncurrent Liabilities 7,688 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 45,029 44,704
Retained earnings 73,075 63,069
Accumulated other comprehensive loss (4,287) (4,945)
Stockholders' equity before deduction for treasury stock 115,605 104,616
Less treasury stock, at cost: 1,102,476,756 shares in 2025 and 1,049,466,187 shares in 2024 62,999 58,303
Total Merck & Co., Inc. stockholders’ equity 52,606 46,313
Noncontrolling Interests 56 59
Total equity 52,662 46,372
Total Liabilities and Equity $ 136,866 $ 117,106
v3.25.4
Consolidated Balance Sheet (Parenthetical) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Statement of Financial Position [Abstract]    
Allowance for doubtful accounts $ 97 $ 89
Inventory classified in other assets $ 5,681 $ 4,193
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, shares issued (in shares) 3,577,103,522 3,577,103,522
Treasury stock, shares (in shares) 1,102,476,756 1,049,466,187
v3.25.4
Consolidated Statement of Equity - USD ($)
$ in Millions
Total
Common Stock
Other Paid-In Capital
Retained Earnings
Accumulated Other Comprehensive Loss
Treasury Stock
Non- controlling Interests
Beginning balance at Dec. 31, 2022 $ 46,058 $ 1,788 $ 44,379 $ 61,081 $ (4,768) $ (56,489) $ 67
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income attributable to Merck & Co., Inc. 365     365      
Other comprehensive income (loss), net of taxes (393)       (393)    
Cash dividends declared on common stock (7,551)     (7,551)      
Treasury stock shares purchased (1,346)         (1,346)  
Net income attributable to noncontrolling interests 12           12
Distributions attributable to noncontrolling interests (25)           (25)
Share-based compensation plans and other 515   130     385  
Ending balance at Dec. 31, 2023 37,635 1,788 44,509 53,895 (5,161) (57,450) 54
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income attributable to Merck & Co., Inc. 17,117     17,117      
Other comprehensive income (loss), net of taxes 216       216    
Cash dividends declared on common stock (7,943)     (7,943)      
Treasury stock shares purchased (1,306)         (1,306)  
Net income attributable to noncontrolling interests 16           16
Distributions attributable to noncontrolling interests (12)           (12)
Share-based compensation plans and other 649   195     453 1
Ending balance at Dec. 31, 2024 46,372 1,788 44,704 63,069 (4,945) (58,303) 59
Increase (Decrease) in Stockholders' Equity [Roll Forward]              
Net income attributable to Merck & Co., Inc. 18,254     18,254      
Other comprehensive income (loss), net of taxes 658       658    
Cash dividends declared on common stock (8,248)     (8,248)      
Treasury stock shares purchased (5,084)         (5,084)  
Net income attributable to noncontrolling interests 9           9
Distributions attributable to noncontrolling interests (12)           (12)
Share-based compensation plans and other 713   325     388  
Ending balance at Dec. 31, 2025 $ 52,662 $ 1,788 $ 45,029 $ 73,075 $ (4,287) $ (62,999) $ 56
v3.25.4
Consolidated Statement of Equity (Parenthetical) - $ / shares
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Statement of Stockholders' Equity [Abstract]      
Common stock, dividends declared (in dollars per share) $ 3.28 $ 3.12 $ 2.96
v3.25.4
Consolidated Statement of Cash Flows - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Cash Flows from Operating Activities      
Net income $ 18,263 $ 17,133 $ 377
Adjustments to reconcile net income to net cash provided by operating activities:      
Amortization 2,793 2,395 2,044
Depreciation 3,045 2,104 1,828
Intangible asset impairment charges 55 39 792
Income from investments in equity securities, net (368) (14) (340)
Charges for certain research and development asset acquisitions 0 3,456 11,409
Deferred income taxes (1,671) (1,249) (1,899)
Share-based compensation 820 761 645
Other 511 510 355
Net changes in assets and liabilities:      
Accounts receivable (1,090) (244) (1,148)
Inventories (1,180) (835) (816)
Trade accounts payable 110 182 (380)
Accrued and other current liabilities (1,841) (2,328) 1,783
Income taxes payable 137 1,023 214
Noncurrent liabilities 195 (49) 456
Other (3,307) (1,416) (2,314)
Net Cash Provided by Operating Activities 16,472 21,468 13,006
Cash Flows from Investing Activities      
Capital expenditures (4,112) (3,372) (3,863)
Purchases of securities and other investments (1,207) (519) (955)
Proceeds from sales of securities and other investments 1,678 377 1,658
Proceeds from sale of Seagen Inc. common stock 0 0 1,145
Acquisition of Verona Pharma plc, net of cash acquired (10,042) 0 0
Acquisition of Eyebiotech Limited, net of cash acquired 0 (1,344) 0
Acquisition of Elanco Animal Health Incorporated aqua business 0 (1,303) 0
Acquisition of Harpoon Therapeutics, Inc., net of cash acquired 0 (746) 0
Acquisition of MK-1045 from Curon Pharmaceutical 0 (700) 0
Acquisition of Prometheus Biosciences, Inc., net of cash acquired 0 0 (10,705)
Acquisition of Imago BioSciences Inc., net of cash acquired 0 0 (1,327)
Other (58) (127) (36)
Net Cash Used in Investing Activities (13,741) (7,734) (14,083)
Cash Flows from Financing Activities      
Payments on debt (2,503) (1,290) (1,755)
Proceeds from issuance of debt 13,880 3,599 5,939
Purchases of treasury stock (5,084) (1,306) (1,346)
Dividends paid to stockholders (8,176) (7,840) (7,445)
Proceeds from exercise of stock options 92 177 125
Other (131) (372) (328)
Net Cash Used in Financing Activities (1,922) (7,032) (4,810)
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash 563 (293) 23
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash 1,372 6,409 (5,864)
Cash, Cash Equivalents and Restricted Cash at Beginning of Year (includes $76, $68 and $79 of restricted cash at January 1, 2025, 2024 and 2023, respectively, included in Other current assets) 13,318 6,909 12,773
Cash, Cash Equivalents and Restricted Cash at End of Year (includes $125, $76 and $68 of restricted cash at December 31, 2025, 2024 and 2023, respectively, included in Other current assets) $ 14,690 $ 13,318 $ 6,909
v3.25.4
Consolidated Statement of Cash Flows (Parenthetical) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Statement of Cash Flows [Abstract]        
Cash, cash equivalents, and restricted cash $ 125 $ 76 $ 68 $ 79
v3.25.4
Nature of Operations
12 Months Ended
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Nature of Operations Nature of Operations
Merck & Co., Inc. (Merck or the Company) is a global health care company that delivers innovative health solutions through its prescription medicines, including biologic therapies, vaccines and animal health products. 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.
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.
v3.25.4
Summary of Accounting Policies
12 Months Ended
Dec. 31, 2025
Accounting Policies [Abstract]  
Summary of Accounting Policies Summary of Accounting Policies
Principles of Consolidation — The consolidated financial statements include the accounts of the Company and all of its subsidiaries in which a controlling interest is maintained. Intercompany balances and transactions are eliminated. Controlling interest is determined by majority ownership interest and the absence of substantive third-party participating rights or, in the case of variable interest entities, by majority exposure to expected losses, residual returns or both. For those consolidated subsidiaries where Merck ownership is less than 100%, the outside shareholders’ interests are shown as Noncontrolling Interests in equity. Investments in affiliates over which the Company has significant influence but not a controlling interest, such as interests in entities owned equally by the Company and a third party that are under shared control, are carried on the equity method basis.
Acquisitions — In a business combination, the acquisition method of accounting requires that the assets acquired and liabilities assumed be recorded as of the date of the acquisition at their respective fair values with limited exceptions. Assets acquired and liabilities assumed in a business combination that arise from contingencies are generally recognized at fair value. If fair value cannot be determined, the asset or liability is recognized if probable and reasonably estimable; if these criteria are not met, no asset or liability is recognized. 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. Accordingly, the Company may be required to value assets at fair value measures that do not reflect the Company’s intended use of those assets. Any excess of the purchase price (consideration transferred) over the estimated fair values of net assets acquired is recorded as goodwill. Transaction costs and costs to restructure the acquired company are expensed as incurred. The operating results of the acquired business are reflected in the Company’s consolidated financial statements after the date of the acquisition.
If the Company determines the assets acquired do not meet the definition of a business under the acquisition method of accounting, the transaction will be accounted for as an asset acquisition rather than a business combination and, therefore, no goodwill will be recorded. In an asset acquisition, acquired in-process research and development (IPR&D) with no alternative future use is charged to expense, currently marketed products are capitalized as intangible assets, and contingent consideration is not recognized at the acquisition date.
Foreign Currency Translation — The net assets of international subsidiaries where the local currencies have been determined to be the functional currencies are translated into U.S. dollars using current exchange rates and results of operations are translated at average exchange rates. The U.S. dollar effects that arise from translating the net assets of these subsidiaries at changing rates are recorded in Other Comprehensive Income (OCI) and remain in Accumulated other comprehensive loss (AOCL) until either the sale or complete or substantially complete liquidation of the subsidiary. For those subsidiaries that operate in highly inflationary economies and for those subsidiaries where the U.S. dollar has been determined to be the functional currency, non-monetary foreign currency
assets and liabilities are translated using historical rates, while monetary assets and liabilities are translated at current rates, with the U.S. dollar effects of rate changes included in Other (income) expense, net.
Cash Equivalents — Cash equivalents consist of certain highly liquid investments with original maturities of less than three months.
Inventories — Inventories are valued at the lower of cost or net realizable value. The cost of a substantial majority of U.S. human health inventories is determined using the last-in, first-out (LIFO) method for both financial reporting and tax purposes. The cost of all other inventories is determined using the first-in, first-out (FIFO) method. Inventories consist of currently marketed products, as well as certain inventories produced in preparation for product launches that are considered by the Company to be probable of obtaining regulatory approval. In evaluating the recoverability of inventories produced in preparation for product launches, the Company considers the likelihood that revenue will be obtained from the future sale of the related inventory together with the status of the product during the research and regulatory approval process.
Investments — Investments in marketable debt securities classified as available-for-sale are reported at fair value. Fair values of the Company’s investments in marketable debt securities are determined using quoted market prices in active markets for identical assets or quoted prices for similar assets or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Changes in fair value that are not impairment related are reported net of taxes in OCI. The Company considers available evidence in evaluating potential impairments of its investments in marketable debt securities, including the extent to which fair value is less than cost, whether an allowance for credit loss is required, as well as adverse factors that could affect the value of the securities. An impairment has occurred if the Company does not expect to recover the entire amortized cost basis of the marketable debt security. If the Company does not intend to sell the impaired debt security, and it is not more likely than not it will be required to sell the debt security before the recovery of its amortized cost basis, the amount of the impairment recognized in earnings, recorded in Other (income) expense, net, is limited to the portion attributed to credit loss. The remaining portion of the impairment related to other factors is recognized in OCI. Realized gains and losses for debt securities are included in Other (income) expense, net.
Investments in publicly traded equity securities are reported at fair value as determined using quoted market prices in active markets for identical assets or quoted prices for similar assets or other inputs that are observable or can be corroborated by observable market data. Changes in fair value are included in Other (income) expense, net. Unrealized gains and losses from investments that are directly owned are determined at the end of the reporting period. Gains and losses from ownership interests in investment funds, which are accounted for as equity method investments, are reported on a one quarter lag. Investments in equity securities without readily determinable fair values are recorded at cost, plus or minus subsequent observable price changes in orderly transactions for identical or similar investments, minus impairments. Such adjustments are recognized in Other (income) expense, net. Realized gains and losses for equity securities are included in Other (income) expense, net.
Revenue Recognition — Recognition of revenue requires evidence of a contract, probable collection of sales proceeds and completion of substantially all performance obligations. Merck acts as the principal in substantially all of its customer arrangements and therefore records revenue on a gross basis. The majority of the Company’s contracts related to the Pharmaceutical and Animal Health segments have a single performance obligation - the promise to transfer goods. Shipping is considered immaterial in the context of the overall customer arrangement and damages or loss of goods in transit are rare. Therefore, shipping is not deemed a separately recognized performance obligation.
The vast majority of revenues from sales of products are recognized at a point in time when control of the goods is transferred to the customer, which the Company has determined is when title and risks and rewards of ownership transfer to the customer and the Company is entitled to payment. The Company recognizes revenue from the sales of vaccines to the U.S. federal government for placement into vaccine stockpiles in accordance with Securities and Exchange Commission (SEC) Interpretation, Commission Guidance Regarding Accounting for Sales of Vaccines and BioTerror Countermeasures to the Federal Government for Placement into the Pediatric Vaccine Stockpile or the Strategic National Stockpile. This interpretation allows companies to recognize revenue for sales of vaccines into U.S. government stockpiles even though these sales might not meet the criteria for revenue recognition under other accounting guidance. For certain services in the Animal Health segment, revenue is recognized over time, generally ratably over the contract term as services are provided. These service revenues are not material.
The nature of the Company’s business gives rise to several types of variable consideration including discounts and returns, which are estimated at the time of sale generally using the expected value method, although the most likely amount method is used for prompt pay discounts.
In the U.S., sales discounts are issued to customers at the point-of-sale, through an intermediary wholesaler (known as chargebacks), or in the form of rebates. Additionally, sales are generally made with a limited right of return under certain conditions. Revenues are recorded net of provisions for sales discounts and returns, which are established at the time of sale. In addition, if collection of accounts receivable is expected to be in excess of one year, sales are recorded net of time value of money discounts, which have not been material.
The U.S. provision for aggregate customer discounts covering chargebacks and rebates was $10.0 billion in 2025, $13.3 billion in 2024 and $12.5 billion in 2023. Chargebacks are discounts that occur when a contracted customer purchases through an intermediary wholesaler. The wholesaler then charges the Company back for the difference between the price initially paid by the wholesaler and the contract price agreed to between Merck and the customer. The provision for chargebacks is based on expected sell-through levels by the Company’s wholesale customers to contracted customers, as well as estimated wholesaler inventory levels. Rebates are amounts 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 to a benefit plan participant. The provision for rebates is based on expected patient usage, as well as inventory levels in the distribution channel to determine the contractual obligation to the benefit providers. The Company uses historical customer segment utilization mix, sales forecasts, changes to product mix and price, inventory levels in the distribution channel, government pricing calculations and prior payment history in order to estimate the expected provision. Amounts accrued for aggregate customer discounts are evaluated on a quarterly basis through comparison of information provided by the wholesalers, health maintenance organizations, pharmacy benefit managers, federal and state agencies, and other customers to the amounts accrued. The accrued balances relative to the provisions for chargebacks and rebates included in Accounts receivable and Accrued and other current liabilities were $295 million and $1.5 billion, respectively, at December 31, 2025 and were $293 million and $2.2 billion, respectively, at December 31, 2024.
Outside of the U.S., variable consideration in the form of discounts and rebates are a combination of commercially-driven discounts in highly competitive product classes, discounts required to gain or maintain reimbursement, or legislatively mandated rebates. In certain European countries, legislatively mandated rebates are calculated based on an estimate of the government’s total unbudgeted health care spending and the Company’s specific payback obligation. Rebates may also be required based on specific product sales thresholds. The Company applies an estimated factor against its actual invoiced sales to represent the expected level of future discount or rebate obligations associated with the sale.
The Company maintains a returns policy that allows its U.S. pharmaceutical customers to return product within a specified period prior to and subsequent to the expiration date (generally, three to six months before and 12 months after product expiration). The estimate of the provision for returns is based upon historical experience with actual returns. Additionally, the Company considers factors such as levels of inventory in the distribution channel, product dating and expiration period, whether products have been discontinued, entrance in the market of generic or other competition, changes in formularies or launch of over-the-counter products, among others. Outside of the U.S., returns are only allowed in certain countries on a limited basis.
Merck’s payment terms for U.S. pharmaceutical products are typically 35 days from receipt of invoice and for U.S. animal health products are typically 30 days from receipt of invoice; however, certain products have longer payment terms, including Keytruda (pembrolizumab), which has payment terms of 90 days. Payment terms for vaccine products in the U.S. typically range from 30 days to 60 days. Outside of the U.S., payment terms are typically 30 days to 90 days, although certain markets have longer payment terms.
See Note 18 for disaggregated revenue disclosures.
Depreciation — Depreciation is provided over the estimated useful lives of the assets, principally using the straight-line method. For tax purposes, accelerated tax methods are used. The estimated useful lives primarily range from 25 to 45 years for Buildings, and from 3 to 15 years for Machinery, equipment and office furnishings. Depreciation expense was $3.0 billion in 2025, $2.1 billion in 2024 and $1.8 billion in 2023.
Advertising and Promotion Costs — Advertising and promotion costs are expensed as incurred. The Company recorded advertising and promotion expenses of $2.3 billion in 2025, $2.4 billion in 2024 and $2.3 billion in 2023.
Software Capitalization — The Company capitalizes certain costs incurred in connection with obtaining or developing internal-use software including external direct costs of material and services, and payroll costs for employees directly involved with the software development. These costs are included in Property, plant and equipment. The Company also capitalizes certain costs incurred to implement cloud computing arrangements, which
are considered service agreements. These costs are included in Other Assets. Capitalized software costs are being amortized over periods ranging from 2 to 10 years (which include contract renewal periods for cloud computing arrangements that are reasonably certain to occur), with the longer lives generally associated with enterprise-wide projects implemented over multiple years. Costs incurred during the preliminary project stage and post-implementation stage, as well as maintenance and training costs, are expensed as incurred.
Goodwill — Goodwill represents the excess of the consideration transferred over the fair value of net assets acquired in a business combination. Goodwill is assigned to reporting units and evaluated for impairment at least annually, or more frequently if impairment indicators exist, by first assessing qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If the Company concludes it is more likely than not that the fair value of a reporting unit is less than its carrying amount, a quantitative fair value test is performed. If the carrying value of a reporting unit is greater than its fair value, a goodwill impairment charge will be recorded for the difference (up to the carrying value of goodwill).
Acquired Intangibles — Intangibles acquired in business combinations and asset acquisitions include product rights, trade names and patents, licenses and other, which are initially recorded at fair value, assigned an estimated useful life, and amortized primarily on a straight-line basis over their estimated useful lives ranging from 2 to 24 years. The Company periodically evaluates whether current facts or circumstances indicate that the carrying values of its acquired intangibles may not be recoverable. If such circumstances are determined to exist, an estimate of the undiscounted future cash flows of these assets, or appropriate asset groupings, is compared to the carrying value to determine whether an impairment exists. If the asset is determined to be impaired, the loss is measured based on the difference between the carrying value of the intangible asset and its fair value, which is determined based on the net present value of estimated future cash flows.
Acquired In-Process Research and Development — IPR&D that the Company acquires in conjunction with a business combination represents the fair value assigned to incomplete research projects which, at the time of acquisition, have not reached technological feasibility. The amounts are capitalized and are accounted for as indefinite-lived intangible assets, subject to impairment testing until completion or abandonment of the projects. Upon successful completion of each IPR&D project, Merck will make a determination as to the then-useful life of the intangible asset, generally determined by the period in which the substantial majority of the cash flows are expected to be generated, and begin amortization. The Company evaluates IPR&D for impairment at least annually, or more frequently if impairment indicators exist, by performing a quantitative test that compares the fair value of the IPR&D intangible asset with its carrying value. If the fair value is less than the carrying amount, an impairment loss is recognized in operating results.
Contingent Consideration for Business Combinations — Certain of the Company’s acquisitions involve the potential for future payment of consideration that is contingent upon the achievement of performance milestones, including product development milestones and royalty payments on future product sales. If the transaction is accounted for as a business combination, the fair value of contingent consideration liabilities is determined at the acquisition date using unobservable inputs. These inputs include the estimated amount and timing of projected cash flows, the probability of success (achievement of the contingent event) and the risk-adjusted discount rate used to present value the probability-weighted cash flows. Subsequent to the acquisition date, at each reporting period until the contingency is resolved, the contingent consideration liability is remeasured at current fair value with changes (either expense or income) recorded in earnings. Significant events that increase or decrease the probability of achieving development and regulatory milestones or that increase or decrease projected cash flows will result in corresponding increases or decreases in the fair values of the related contingent consideration obligations.
Research and Development — Research and development is expensed as incurred. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Research and development expenses include restructuring costs and IPR&D impairment charges. In addition, research and development expenses include expense or income related to changes in the estimated fair value measurement of liabilities for contingent consideration associated with IPR&D assets. Research and development expenses also include upfront and milestone payments related to asset acquisitions and licensing transactions involving clinical development programs that have not yet received regulatory approval.
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. When Merck is the principal on sales transactions with third parties, the Company recognizes sales, cost of sales and selling, general and administrative expenses on a gross basis. Profit sharing amounts it pays to its collaborative partners are recorded within Cost of sales. When the collaborative partner is the principal on sales transactions with
third parties, the Company records profit sharing amounts received from its collaborative partners as alliance revenue (within Sales). Alliance revenue is recorded net of cost of sales and includes an adjustment to share commercialization costs between the partners in accordance with the collaboration agreement. The adjustment is determined by comparing the commercialization costs Merck has incurred directly and reported within Selling, general and administrative expenses with the costs the collaborative partner has incurred. Research and development costs Merck incurs related to collaborations are recorded within Research and development expenses. Cost reimbursements to the collaborative partner or payments received from the collaborative partner to share these costs pursuant to the terms of the collaboration agreements are recorded as increases or decreases to Research and development expenses, respectively.
In addition, the terms of the collaboration agreements may require the Company to make payments based upon the achievement of certain developmental, regulatory approval or commercial milestones. Upfront and milestone payments payable by Merck to collaborative partners prior to regulatory approval are expensed as incurred and included in Research and development expenses. Payments due to collaborative partners upon or subsequent to regulatory approval are capitalized and amortized to Cost of sales over the estimated useful life of the corresponding intangible asset, provided that future cash flows support the amounts capitalized. Sales-based milestones payable by Merck to collaborative partners are accrued and capitalized, subject to cumulative amortization catch-up, when determined by the Company to be probable of being achieved based on future sales forecasts. The amortization catch-up is calculated either from the time of the first regulatory approval for products that were unapproved at the time the collaboration was formed or, for new indications of approved products, from the time of the formation of the collaboration. The related intangible asset that is recognized is amortized to Cost of sales over its estimated remaining useful life, subject to impairment testing.
Share-Based Compensation — The Company expenses all share-based payments to employees over the requisite service period based on the grant-date fair value of the awards.
Restructuring Costs — The Company records liabilities for costs associated with exit or disposal activities in the period in which the liability is incurred. In accordance with existing benefit arrangements, future employee termination costs to be incurred in conjunction with involuntary separations are accrued when such separations are probable and estimable. When accruing these costs, the Company will recognize the amount within a range of costs that is the best estimate within the range. When no amount within the range is a better estimate than any other amount, the Company recognizes the minimum amount within the range. Costs for one-time termination benefits in which the employee is required to render service until termination in order to receive the benefits are recognized ratably over the future service period.
Contingencies and Legal Defense Costs — The Company records accruals for contingencies and legal defense costs expected to be incurred in connection with a loss contingency when it is probable that a liability has been incurred and the amount can be reasonably estimated.
Taxes on Income — Deferred taxes are recognized for the future tax effects of temporary differences between financial and income tax reporting based on enacted tax laws and rates. The Company evaluates tax positions to determine whether the benefits of tax positions are more likely than not of being sustained upon audit based on the technical merits of the tax position. For tax positions that are more likely than not of being sustained upon audit, the Company recognizes the amount of the benefit that is greater than 50% likely of being realized upon ultimate settlement in the financial statements. For tax positions that are not more likely than not of being sustained upon audit, the Company does not recognize any portion of the benefit in the financial statements. The Company recognizes interest and penalties associated with uncertain tax positions as a component of Taxes on Income. The Company accounts for the tax effects of the tax on global intangible low-taxed income (GILTI) of certain foreign subsidiaries in the income tax provision in the period the tax arises. H.R. 1 - One Big Beautiful Bill Act (OBBBA) renamed the provision for taxes on foreign earnings from GILTI to net controlled foreign corporation tested income (NCTI). The Company’s policy for releasing disproportionate income tax effects from AOCL is to utilize the item-by-item approach.
Reclassifications — Certain reclassifications have been made to prior year amounts to conform to the current year presentation.
Use of Estimates — The consolidated financial statements are prepared in conformity with accounting principles generally accepted in the U.S. (GAAP) and, accordingly, include certain amounts that are based on management’s best estimates and judgments. Estimates are used when accounting for amounts recorded in connection with acquisitions, including initial fair value determinations of assets and liabilities in a business combination (primarily IPR&D, other intangible assets and contingent consideration), as well as subsequent fair value
measurements. Additionally, estimates are used in determining such items as provisions for sales discounts, rebates and returns, depreciable and amortizable lives, recoverability of inventories (including those produced in preparation for product launches), amounts recorded for contingencies, environmental liabilities, contingent sales-based milestone payments and other reserves, pension and other postretirement benefit plan assumptions, share-based compensation assumptions, restructuring costs, impairments of long-lived assets (including intangible assets and goodwill) and investments, and taxes on income. Because of the uncertainty inherent in such estimates, actual results may differ from these estimates.
Recently Adopted Accounting Standards — 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 Company elected to prospectively adopt the guidance effective for 2025 annual reporting. The adoption primarily resulted in incremental disclosures to the Company’s income tax disclosures contained in Note 15.
In September 2025, the FASB issued amended guidance to reduce the complexity of evaluating whether contracts are derivatives by adding a scope exception (which may apply to certain R&D funding arrangements) to exclude from derivative accounting non-exchange-traded contracts with variables (underlyings) that are based on operations or activities specific to one of the parties to the contract. The Company adopted the guidance on October 1, 2025, effective for full year 2025 on a prospective basis. The Company did not have any contracts that were affected by the adoption of this new standard; therefore, there was no impact to the Company’s consolidated financial statements upon adoption.
Recently Issued Accounting Standards Not Yet Adopted — In November 2024, the FASB issued guidance intended to improve financial reporting by requiring entities to disclose additional information about specific expense categories for interim and annual reporting periods. The guidance is effective for 2027 annual reporting and 2028 interim reporting. Early adoption is permitted. The guidance, which can be applied on a prospective or retrospective basis, will result in incremental disclosures within the footnotes to the Company’s financial statements.
In December 2025, the FASB issued guidance that includes requirements for recognition of government grants in a Company’s financial statements as well as disclosure requirements, including the nature of the government grant received, the accounting policies used to account for the grant, and significant terms and conditions of the grant. The guidance is effective for 2029 interim and annual reporting on a modified prospective, modified retrospective or retrospective approach. Early adoption is permitted as of the beginning of an annual reporting period. The Company is currently evaluating the impact of adoption on its consolidated financial statements.
v3.25.4
Acquisitions, Research Collaborations and Licensing Agreements
12 Months Ended
Dec. 31, 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.
Recent Transactions
In January 2026, Merck acquired Cidara Therapeutics, Inc. (Cidara), a biotechnology company developing drug-Fc conjugate (DFC) therapeutics, for approximately $9.2 billion (including payments to settle share-based equity awards). Cidara’s lead DFC candidate, MK-1406 (formerly CD388), is a long-acting antiviral designed to prevent seasonal and pandemic influenza. MK-1406 is currently being evaluated among adult and adolescent participants who are at higher risk of developing complications from influenza. Merck anticipates the transaction will be accounted for as an asset acquisition since MK-1406 is expected to account for substantially all of the fair value of the gross assets to be acquired (excluding cash and deferred income taxes). Merck expects to record a charge of approximately $9.0 billion to Research and development expenses in the first quarter of 2026 for acquired IPR&D with no alternative future use. There are no future contingent payments associated with the acquisition.
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, Merck made a $150 million upfront payment, which the Company recorded as a charge to Research and development expenses in 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 $10.4 billion (including payments to settle share-based equity awards). Through this acquisition, Merck acquired Ohtuvayre (ensifentrine), an inhaled phosphodiesterases 3 and 4 (PDE3 and PDE4) inhibitor, which was approved in the U.S. in June 2024 for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in adults. Ohtuvayre is also being evaluated in clinical trials for the treatment of non-cystic fibrosis bronchiectasis. The transaction was accounted for as an asset acquisition since Ohtuvayre accounted for substantially all of the fair value of the gross assets acquired (excluding cash and deferred income taxes). Merck recorded an intangible asset of $12.1 billion for Ohtuvayre, cash of $495 million, inventories of $522 million (including $498 million of step-up to fair value), deferred tax liabilities of $2.7 billion and other net liabilities of $51 million. The estimated fair value of the Ohtuvayre intangible asset was determined using an income approach. Actual cash flows are likely to be different than those assumed. The Ohtuvayre intangible asset will be amortized over its estimated useful life of nine years, subject to impairment testing. 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 up to $700 million in the fourth quarter of 2026 (which is non-refundable, subject to the termination provisions of the agreement) to fund a portion of the Company’s development costs for MK-2870, sacituzumab tirumotecan (sac-TMT), expected to be incurred throughout 2026. The funding will be recognized as a reduction to Research and development expenses as Merck incurs applicable development costs for the sac-TMT program. Upon receipt of regulatory approval for an indication in the U.S. for first-line triple-negative-breast cancer (TroFuse-011 trial), Blackstone will be eligible to receive low-to-mid single-digit royalties on net sales of sac-TMT subsequent to such approval across all approved indications in Merck’s marketing territories. Sac-TMT is an investigational trophoblast cell-surface antigen 2 (TROP2)-directed antibody drug conjugate (ADC) being developed as part of an exclusive license and collaboration agreement with Kelun-Biotech that is currently in clinical development for the treatment of a variety of cancers. The agreement between Merck and Kelun-Biotech with respect to sac-TMT is unchanged by the agreement with Blackstone. Merck 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.
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. 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 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 December 2024, Merck closed an exclusive global license to develop, manufacture and commercialize MK-2010 (LM-299), a novel investigational PD-1/vascular endothelial growth factor (VEGF) bispecific antibody from LaNova Medicines Ltd (LaNova). Merck recorded a charge of $588 million to Research and development expenses in 2024 for the upfront payment, which was made in January 2025. In 2025, the technology transfer for MK-2010 (LM-299) was completed. Accordingly, Merck made a $300 million payment to LaNova (acquired by Sino Biopharmecutical Limited), which was recorded as a charge to Research and development expenses in 2025. LaNova is also eligible to receive future contingent developmental milestone payments of up to $140 million, regulatory milestone payments of up to $860 million and sales-based milestone payments of up to $1.4 billion.
Also in December 2024, Merck closed an exclusive global license to develop, manufacture and commercialize MK-4082 (HS-10535), an investigational preclinical oral small molecule GLP-1 receptor agonist from Hansoh Pharma (Hansoh). Merck recorded a charge of $112 million to Research and development expenses in 2024 for the upfront payment, which was made in February 2025. Hansoh is also eligible to receive contingent development-related milestone payments of up to $115 million (of which $15 million was paid in 2025), regulatory milestone payments of up to $315 million and sales-based milestone payments of up to $1.47 billion, as well as tiered royalties ranging from a high-single-digit rate to a low-double-digit rate on future net sales of MK-4082 (HS-10535), if approved. Under the agreement, Hansoh may co-promote or solely commercialize MK-4082 (HS-10535) in Chinese mainland, Hong Kong and Macau, subject to certain conditions.
In September 2024, Merck acquired MK-1045 (formerly 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 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:
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 2024 for acquired IPR&D with no alternative future use. Additionally, developmental milestones of $100 million were recorded as charges to Research and development expenses in each of 2025 and 2024.
Additionally in July 2024, Merck and Orion Corporation (Orion) announced the mutual exercise of an option to convert the companies’ ongoing co-development and co-commercialization agreement for opevesostat (MK-5684/ODM-208), an investigational cytochrome P450 11A1 (CYP11A1) inhibitor, and other candidates targeting CYP11A1, into an exclusive global license for Merck. With the exercise of the option, Merck assumed full responsibility for all past and future development and commercialization expenses associated with the candidates covered by the original agreement entered into in 2022. In addition, Orion became eligible to receive developmental milestone payments of up to $30 million, regulatory milestone payments of up to $625 million and sales-based milestone payments of up to $975 million, as well as annually tiered royalties ranging from a low double-digit rate up to a rate in the low twenties on net sales for any commercialized licensed product. Orion retained responsibility for the manufacture of clinical and commercial supply for Merck. No payment was associated with the exercise of the option, which became effective in September 2024.
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 2024 for acquired IPR&D with no alternative future use. 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 4 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 low single digit royalty on net sales is payable to Alteogen. In 2025, the U.S. Food and Drug Administration (FDA) approved Keytruda Qlex (pembrolizumab and berahyaluronidase alfa-pmph) injection and the European Commission approved a new subcutaneous route of administration and a new pharmaceutical form (solution for injection) of Keytruda. These approvals triggered regulatory milestone payments of $40 million in the aggregate from Merck to Alteogen. Additionally, following FDA and EC approvals, the Company determined that it was probable that sales of Keytruda Qlex in the future would trigger $890 million of sales-based milestone payments from Merck to Alteogen. Accordingly, Merck recorded a $930 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 is being amortized over its estimated useful life through December 2030. The $40 million of regulatory milestone payments were made in 2025; the future sales-based milestone payments will be paid upon achievement of the corresponding milestone.
2023 Transactions
In October 2023, Merck and Daiichi Sankyo entered into a global development and commercialization agreement for three of Daiichi Sankyo’s deruxtecan (DXd) ADC candidates: patritumab deruxtecan (HER3-DXd) (MK-1022), ifinatamab deruxtecan (I-DXd) (MK-2400) and raludotatug deruxtecan (R-DXd) (MK-5909). See Note 4 for additional information related to this collaboration.
In June 2023, Merck acquired Prometheus Biosciences, Inc. (Prometheus), a clinical-stage biotechnology company pioneering a precision medicine approach for the discovery, development, and commercialization of novel therapeutic and companion diagnostic products for the treatment of immune-mediated diseases. Total consideration paid of $11.0 billion included $1.2 billion of costs to settle share-based equity awards (including $700 million to settle unvested equity awards). Prometheus’ lead candidate, tulisokibart (MK-7240, formerly PRA023), is a humanized monoclonal antibody directed to tumor necrosis factor-like ligand 1A, a central amplifier of inflammatory pathways and fibrotic mechanisms in inflammatory bowel disease. Tulisokibart is being developed for the treatment of immune-mediated diseases including ulcerative colitis, Crohn’s disease, and other autoimmune conditions. The transaction was accounted for as an asset acquisition since tulisokibart accounted for substantially all of the fair value of the gross assets acquired (excluding cash and deferred income taxes). Merck recorded net assets of $877 million, including cash of $368 million, investments of $296 million, deferred tax assets of $218 million and other net liabilities of $5 million, as well as a charge of $10.2 billion to Research and development expenses in 2023 for acquired IPR&D with no alternative future use. There are no future contingent payments associated with the acquisition.
In February 2023, Merck and Kelun-Biotech closed a license and collaboration agreement expanding their relationship in which Merck gained exclusive rights for the research, development, manufacture and commercialization of up to seven investigational preclinical ADCs for the treatment of cancer. Kelun-Biotech retained the right to research, develop, manufacture and commercialize certain licensed and option ADCs for Chinese mainland, Hong Kong and Macau. Merck made an upfront payment of $175 million, which was recorded as a charge to Research and development expenses in 2023. In October 2023, Merck notified Kelun-Biotech it was terminating two of the seven candidates under the agreement. Subsequently, in April 2024, Merck notified Kelun-Biotech it was terminating one additional candidate under the agreement. In July 2024, Merck notified Kelun-Biotech that it was exercising an existing license option for one of the candidates under the agreement, granting Merck a license for the development, manufacture and commercialization worldwide excluding China. There are now three candidates licensed under the original agreement and one candidate for which the license option remains unexercised. Merck paid Kelun-Biotech $38 million in connection with the July 2024 option exercise, following which Kelun-Biotech is eligible to receive contingent payments aggregating up to $540 million in development-related payments (of which $20 million was paid in 2025), $1.5 billion in regulatory milestones, and $3.1 billion in sales-based milestones, if Kelun-Biotech does not retain Chinese mainland, Hong Kong and Macau rights for the remaining option ADC and all remaining candidates achieve regulatory approval. In addition, Kelun-Biotech is eligible to receive tiered royalties ranging from a mid-single-digit rate to a low-double-digit rate on future net sales for any commercialized ADC product. Also, in connection with the agreement, Merck invested $100 million in Kelun-Biotech shares in January 2023.
In January 2023, Merck acquired Imago BioSciences, Inc. (Imago), a clinical-stage biopharmaceutical company developing new medicines for the treatment of myeloproliferative neoplasms and other bone marrow diseases, for $1.35 billion (including payments to settle share-based equity awards) and also incurred approximately $60 million of transaction costs. Imago’s lead candidate, bomedemstat (MK-3543, formerly IMG-7289), is an investigational orally available lysine-specific demethylase 1 inhibitor currently being evaluated in multiple clinical trials for the treatment of essential thrombocythemia, myelofibrosis, and polycythemia vera, in addition to other indications. The transaction was accounted for as an asset acquisition since bomedemstat represented substantially all of the fair value of the gross assets acquired (excluding cash and deferred income taxes). Merck recorded net assets of $219 million, as well as a charge of $1.2 billion to Research and development expenses in 2023 for acquired IPR&D with no alternative future use. There are no future contingent payments associated with the acquisition.
v3.25.4
Collaborative Arrangements
12 Months Ended
Dec. 31, 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 the simplification of the governance structure related to Koselugo. In exchange, Merck received a $150 million upfront payment in 2025 (which was recorded within Sales as alliance revenue in 2025) and $150 million in February 2026 (which will be recorded within Sales as alliance revenue in 2026). Merck may also receive $150 million in the first quarter of 2027 and $100 million in the first quarter of 2028, subject to an annual election by AstraZeneca in January of each year as discussed below. Additionally, the amended agreement provided for Merck to receive contingent regulatory milestone payments of up to $175 million in the aggregate, all of which were triggered in 2025 and recorded within Sales as alliance revenue. Of these milestone amounts, $50 million is due from AstraZeneca in 2026, $50 million is due in 2027 and $75 million is due in 2028. The Company is also receiving mid-single-digit royalties on net sales (which are included within Sales as alliance revenue). Merck remains eligible to receive future contingent payments for the achievement of sales-based milestones of up to $235 million. AstraZeneca has the option in January of 2027 or January 2028 to revert back to the income and cost sharing terms of the original agreement (in which case any future annual, contingent milestone, and royalty payments referenced above would no longer be due) although Merck would retain any payments made by AstraZeneca prior to the exercise of that option and any amounts due from AstraZeneca would remain payable to Merck.
As part of the initial collaboration agreement, Merck made an upfront payment to AstraZeneca and also made payments over a multi-year period for certain license options. In addition, the initial collaboration agreement provided for contingent payments from Merck to AstraZeneca related to the successful achievement of sales-based and regulatory milestones.
In 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). Merck recognized $48 million of cumulative amortization catch-up expense related to the recognition of the $100 million Koselugo milestone in 2024. 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 regulatory approvals triggering capitalized milestone payments from Merck to AstraZeneca of $245 million and $105 million in 2024 and 2023, respectively (both of 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 $844 million and $38 million, respectively, at December 31, 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:
Years Ended December 31202520242023
Alliance revenue - Lynparza$1,450 $1,311 $1,199 
Alliance revenue - Koselugo (1)
436 170 97 
Total alliance revenue$1,886 $1,481 $1,296 
Cost of sales (2)
338 378 311 
Selling, general and administrative133 165 192 
Research and development36 77 79 
December 3120252024
Receivables from AstraZeneca included in Other current assets (3)
$451 $424 
Receivables from AstraZeneca included in Other assets (3)
125 — 
Payables to AstraZeneca included in Accrued and other current liabilities (4)
6 713 
(1)    Amounts in 2025 include the $150 million upfront payment and $175 million regulatory milestones triggered as a result of the amendment to the collaboration agreement noted above.
(2)    Represents amortization of capitalized milestone payments. Amount in 2024 includes $48 million of cumulative amortization catch-up expense as noted above.
(3)    Balance at December 31, 2025 includes milestone receivables.
(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 2023, Merck determined it was probable that sales of Lenvima in the future would trigger $250 million of sales-based milestone payments from Merck to Eisai. Accordingly, Merck recorded $250 million of liabilities (of which $125 million was subsequently paid in each of 2024 and 2023) and corresponding increases to the intangible asset related to Lenvima. Merck also recognized $154 million of cumulative amortization catch-up expense related to the recognition of these milestones in 2023. 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 $201 million at December 31, 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:
Years Ended December 31202520242023
Alliance revenue - Lenvima$1,053 $1,010 $960 
Cost of sales (1)
241 241 381 
Selling, general and administrative134 159 189 
Research and development11 21 66 
December 3120252024
Receivables from Eisai included in Other current assets
$271 $257 
(1)     Represents amortization of capitalized milestone payments. Amount in 2023 includes $154 million of cumulative amortization catch-up expense as noted above.
Bayer AG
In 2014, the Company entered into a worldwide clinical development collaboration with Bayer AG (Bayer) to market and develop soluble guanylate cyclase (sGC) modulators including Bayer’s Adempas (riociguat) and Verquvo (vericiguat). The two companies have implemented a joint development and commercialization strategy. Under the agreement, Bayer commercializes Adempas in the Americas, while Merck commercializes in the rest of the world. For Verquvo, Merck commercializes in the U.S. and Bayer commercializes in the rest of the world. Both companies share in development costs and profits on sales. Merck records sales of Adempas and Verquvo in its marketing territories, as well as alliance revenue. Alliance revenue represents Merck’s share of profits from sales of Adempas and Verquvo in Bayer’s marketing territories, which are product sales net of cost of sales and commercialization costs. Cost of sales includes Bayer’s share of profits from sales in Merck’s marketing territories. The agreement provided for contingent payments from Merck to Bayer related to the successful achievement of sales-based milestones. There are no such payments remaining under this collaboration.
The intangible asset balances related to Adempas (which includes the acquired intangible asset balance, as well as capitalized sales-based milestone payments attributed to Adempas) and Verquvo (which reflects the portion of the final sales-based milestone payment that was attributed to Verquvo) were $280 million and $40 million, respectively, at December 31, 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:
Years Ended December 31202520242023
Alliance revenue - Adempas/Verquvo$470 $415 $367 
Net sales of Adempas recorded by Merck312 287 255 
Net sales of Verquvo recorded by Merck48 37 36 
Total sales$830 $739 $658 
Cost of sales (1)
256 244 224 
Selling, general and administrative97 111 131 
Research and development56 102 90 
December 3120252024
Receivables from Bayer included in Other current assets
$167 $160 
Payables to Bayer included in Accrued and other current liabilities
81 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:
Years Ended December 31202520242023
Net sales of Lagevrio recorded by Merck
$380 $964 $1,428 
Cost of sales (1)
235 554 852 
Selling, general and administrative
54 57 97 
Research and development
31 13 60 
December 3120252024
Receivables from Ridgeback included in Other current assets
$27 $— 
Payables to Ridgeback included in Accrued and other current liabilities (2)
11 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 3). The companies are planning to evaluate gocatamig in combination with ifinatamab deruxtecan in certain patients with small cell lung cancer, as well as other potential combinations. Merck received an upfront cash payment of $170 million from Daiichi Sankyo (recorded within Other (income) expense, net) and has also satisfied a contingent quid obligation from the original collaboration agreement. The companies will jointly develop and commercialize gocatamig
worldwide and share research and development costs, as well as commercialization expenses. Research and development expenses related to gocatamig in combination with ifinatamab deruxtecan will be shared in a manner consistent with the original agreement for ifinatamab deruxtecan. Merck will be solely responsible for manufacturing and supply of gocatamig. If approved, Merck will generally record sales for gocatamig worldwide (Merck will be the principal on sales transactions) and the companies will equally share expenses as well as profits worldwide, except for Japan where Merck retains exclusive rights, and Daiichi Sankyo will receive a 5% sales-based royalty.
Summarized financial information related to this collaboration is as follows:
Years Ended December 31202520242023
Cost of sales (1)
$66 $— $— 
Selling, general and administrative
28 26 
Research and development (2)
524 351 5,549 
December 3120252024
Receivables from Daiichi Sankyo included in Other current assets
$15 $
Payables to Daiichi Sankyo included in Accrued and other current liabilities (3)
113 817 
(1)    Represents Merck’s share of certain inventory-related costs.
(2)    Expenses in 2023 include the $5.5 billion charge for the upfront and continuing option payments noted above.
(3)    Balance at December 31, 2024 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 $236 million of shared facility costs at December 31, 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:
Years Ended December 31202520242023
Selling, general and administrative
$27 $16 $
Research and development (1)
375 358 218 
December 3120252024
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. 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 $525 million in 2025, $371 million in 2024 and $212 million in 2023.
v3.25.4
Restructuring
12 Months Ended
Dec. 31, 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 $2.0 billion in 2025 related to the 2025 Restructuring Program, which includes charges of $910 million to Cost of sales for the accelerated depreciation of manufacturing lines at two sites.
In January 2024, the Company approved a restructuring program (2024 Restructuring Program) intended to continue the optimization of the Company’s Human Health global manufacturing network as the future pipeline shifts to new modalities and also optimize the Animal Health global manufacturing network to improve supply reliability and increase efficiency. The actions contemplated under the 2024 Restructuring Program are expected to be substantially completed by the end of 2031, with the cumulative pretax costs to be incurred by the Company to implement the program estimated to be approximately $4.0 billion. Approximately 50% of the cumulative pretax costs will be non-cash, relating primarily to the accelerated depreciation of facilities to be closed or divested. The remainder of the costs will result in cash outlays, relating primarily to facility shut-down costs. The Company recorded total pretax costs of $539 million and $888 million in 2025 and 2024, respectively, related to the 2024 Restructuring Program, bringing total cumulative pretax costs incurred through December 31, 2025 to $1.6 billion.
In 2019, Merck approved a global restructuring program (2019 Restructuring Program) as part of a worldwide initiative focused on optimizing the Company’s manufacturing and supply network, as well as reducing its global real estate footprint. The actions under the 2019 Restructuring Program were substantially complete at the end of 2023 and, as of January 1, 2024, any remaining activities are being accounted for as part of the 2024 Restructuring Program.
For segment reporting, restructuring charges are unallocated expenses.
The following table summarizes the charges related to restructuring program activities by type of cost:
Accelerated
Depreciation
Separation
Costs
Other Exit Costs
Total
Year Ended December 31, 2025
2025 Restructuring Program
Cost of sales$910 $ $322 $1,232 
Selling, general and administrative
  2 2 
Research and development
  175 175 
Restructuring costs 548 55 603 
910 548 554 2,012 
2024 Restructuring Program
Cost of sales247  5 252 
Selling, general and administrative  1 1 
Restructuring costs 61 225 286 
247 61 231 539 
$1,157 $609 $785 $2,551 
Year Ended December 31, 2024
2024 Restructuring Program
Cost of sales$254 $— $241 $495 
Selling, general and administrative— — 83 83 
Research and development— — 
Restructuring costs— 122 187 309 
$254 $122 $512 $888 
Year Ended December 31, 2023
2024 Restructuring Program
Cost of sales$— $— $62 $62 
Restructuring costs— 115 13 128 
— 115 75 190 
2019 Restructuring Program
Cost of sales131 — 18 149 
Selling, general and administrative— 113 122 
Research and development— — 
Restructuring costs— 339 132 471 
 140 339 264 743 
$140 $454 $339 $933 
Accelerated depreciation costs primarily relate to manufacturing, research and administrative facilities to be fully or partially closed or divested and equipment to be disposed of as part of the programs. Accelerated depreciation costs represent the difference between the depreciation expense to be recognized over the revised useful life of the asset, based upon the anticipated date the site will be closed or divested or the equipment disposed of, and depreciation expense as determined utilizing the useful life prior to the restructuring actions. All the sites will continue to operate up through the respective closure dates and, since future undiscounted cash flows are sufficient to recover the respective book values, Merck is recording accelerated depreciation over the revised useful life of the site assets. Anticipated site closure dates, particularly related to manufacturing locations, have been and may continue to be adjusted to reflect changes resulting from regulatory or other factors.
Separation costs are associated with actual headcount reductions, as well as involuntary headcount reductions which were probable and could be reasonably estimated.
Other exit costs in 2025, 2024 and 2023 include asset impairment, facility shut-down, contractual termination, and other related costs, as well as pretax gains and losses resulting from the sales of facilities and related assets. Additionally, other activity includes certain employee-related costs associated with pension and other postretirement benefit plans (see Note 13) and share-based compensation.
The following table summarizes the charges and spending related to restructuring program activities:
Accelerated
Depreciation
Separation
Costs
Other Exit Costs
Total
2025 Restructuring Program
Restructuring reserves January 1, 2025$— $— $— $— 
Expenses910 548 554 2,012 
(Payments) receipts, net (46)(50)(96)
Non-cash activity(910) (216)(1,126)
Restructuring reserves December 31, 2025$ $502 $288 $790 
2024 Restructuring Program
Restructuring reserves January 1, 2024
$— $681 $31 $712 
Expenses254 122 512 888 
(Payments) receipts, net— (239)(206)(445)
Non-cash activity(254)— (337)(591)
Restructuring reserves December 31, 2024
— 564 — 564 
Expenses247 61 231 539 
(Payments) receipts, net (119)(210)(329)
Non-cash activity(247) (21)(268)
Restructuring reserves December 31, 2025
$ $506 $ $506 
v3.25.4
Financial Instruments
12 Months Ended
Dec. 31, 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 Consolidated Balance Sheet. Changes in the fair value of derivative contracts are recorded each period in either current earnings or OCI depending on whether the derivative is designated as part of a hedge transaction and, if so, the type of hedge transaction. For derivatives that are designated as cash flow hedges, the unrealized gains or losses on these contracts are recorded in AOCL and reclassified into Sales when the hedged anticipated revenue is recognized. 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 years ended December 31, 2025, 2024 or 2023. 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 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 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 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 Consolidated Statement of Income are shown below:
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income (1)
Amount of Pretax (Gain) Loss Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing
Years Ended December 31202520242023202520242023
Net Investment Hedging Relationships
Foreign exchange contracts$32 $(30)$— $(15)$(4)$
Euro-denominated notes591 (192)105  — — 
(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 December 31, 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.
Par Value of DebtNumber of Interest Rate Swaps HeldTotal 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. In February 2026, the Company entered into an additional interest rate swap contract with a notional amount of $250 million related to its 5.00% notes due 2053. The cash flows from these contracts are reported as operating activities in the Consolidated Statement of Cash Flows.
The table below presents the location of amounts recorded in the Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges as of December 31:
Carrying Amount of Hedged Liabilities
Cumulative Amount of Fair Value Hedging Adjustment Increase Included in the Carrying Amount
2025202420252024
Balance Sheet Caption
Long-Term Debt $1,810 $1,509 $70 $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 as of December 31:
  20252024
  Fair Value of
Derivative
U.S. Dollar
Notional
Fair Value of
Derivative
U.S. Dollar
Notional
 AssetLiabilityAssetLiability
Derivatives Designated as Hedging InstrumentsBalance Sheet Caption      
Interest rate swap contracts
Other Assets
$71 $ $1,750 $17 $— $1,500 
Foreign exchange contractsOther current assets113  6,430 323 — 8,662 
Foreign exchange contractsOther Assets32  1,793 66 — 2,125 
Foreign exchange contractsAccrued and other current liabilities 131 4,726 — 162 
Foreign exchange contractsOther Noncurrent Liabilities 1 13 — 16 
  $216 $132 $14,712 $406 $$12,465 
Derivatives Not Designated as Hedging InstrumentsBalance Sheet Caption      
Foreign exchange contractsOther current assets$107 $ $11,643 $323 $— $12,544 
Foreign exchange contractsAccrued and other current liabilities 191 13,579 — 343 13,551 
Foreign exchange contractsOther Noncurrent Liabilities 1 357 — — — 
  $107 $192 $25,579 $323 $343 $26,095 
  $323 $324 $40,291 $729 $345 $38,560 
As noted above, the Company records its derivatives on a gross basis in the 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 as of December 31:
20252024
AssetLiabilityAssetLiability
Gross amounts recognized in the consolidated balance sheet$323 $324 $729 $345 
Gross amounts subject to offset in master netting arrangements not offset in the consolidated balance sheet(245)(245)(299)(299)
Cash collateral received
(1) (165)— 
Net amounts$77 $79 $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:
Years Ended December 31202520242023202520242023202520242023
Financial Statement Caption in which Effects of Fair Value or Cash Flow Hedges are RecordedSales
Other (income) expense, net (1)
Other comprehensive income (loss)
$65,011 $64,168 $60,115 $151 $(24)$466 $658 $216 $(393)
Loss (gain) on fair value hedging relationships:
Interest rate swap contracts
Hedged items — — 53 (39)56  — — 
Derivatives designated as hedging instruments — — (54)39 (57) — — 
Impact of cash flow hedging relationships:
Foreign exchange contracts
Amount of (loss) gain recognized in OCI on derivatives
 — —  — — (577)508 114 
(Decrease) increase in Sales as a result of AOCL reclassifications
(106)167 249  — — 106 (167)(249)
Interest rate contracts
Amount of gain recognized in Other (income) expense, net on derivatives
 — — (1)(1)(1) — — 
Amount of gain (loss) recognized in OCI on derivatives
 — —  — — 28 (1)13 
(1)    Interest expense is a component of Other (income) expense, net.
The table below provides information regarding the income statement effects of derivatives not designated as hedging instruments:
Amount of Derivative Pretax (Gain) Loss Recognized in Income
Years Ended December 31202520242023
Derivatives Not Designated as Hedging InstrumentsIncome Statement Caption
Foreign exchange contracts (1)
Other (income) expense, net$(196)$251 $(6)
Foreign exchange contracts (2)
Sales21 (28)
(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 December 31, 2025, the Company estimates $178 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 at December 31 is as follows:
 
 20252024
 Amortized
Cost
Gross UnrealizedFair
Value
Amortized
Cost
Gross UnrealizedFair
Value
GainsLossesGainsLosses
U.S. government and agency securities$100 $ $ $100 $188 $— $— $188 
Foreign government bonds
1   1 — — — — 
Commercial paper    348 — — 348 
Total debt securities$101 $ $ $101 $536 $— $— $536 
Publicly traded equity securities (1)
1,392 920 
Total debt and publicly traded equity securities$1,493 $1,456 
(1)    Unrealized net gains of $474 million were recorded in Other (income) expense, net in 2025 on equity securities still held at December 31, 2025. Unrealized net losses of $30 million were recorded in Other (income) expense, net in 2024 on equity securities still held at December 31, 2024.
At December 31, 2025 and 2024, the Company also had $831 million and $863 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 2025, the Company recorded unrealized gains of $3 million and unrealized losses of $70 million related to certain of these equity investments still held at December 31, 2025. During 2024, the Company recorded unrealized gains of $19 million and unrealized losses of $51 million related to certain of these equity investments still held at December 31, 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 December 31, 2025 were $292 million and $166 million, respectively.
At December 31, 2025, 2024 and 2023, the Company also had $224 million, $267 million and $417 million, respectively, recorded in Other Assets for equity securities held through ownership interests in investment funds. Losses recorded in Other (income) expense, net relating to these investment funds were $55 million, $29 million and $106 million for the years ended December 31, 2025, 2024 and 2023, 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 at December 31 are summarized below:
 Fair Value Measurements UsingFair Value Measurements Using
Level 1Level 2Level 3TotalLevel 1Level 2Level 3Total
  20252024
Assets
Investments
Foreign government bonds
$ $1 $ $1 $— $— $— $— 
Commercial paper    — 348 — 348 
U.S. government and agency securities    — 99 — 99 
Publicly traded equity securities955   955 463 — — 463 
 955 1  956 463 447 — 910 
Other assets (1)
U.S. government and agency securities100   100 89 — — 89 
Publicly traded equity securities (2)
437   437 457 — — 457 
537   537 546 — — 546 
Derivative assets (3)
Forward exchange contracts 168  168 — 499 — 499 
Purchased currency options 84  84 — 213 — 213 
Interest rate swaps 71  71 — 17 — 17 
  323  323 — 729 — 729 
Total assets$1,492 $324 $ $1,816 $1,009 $1,176 $— $2,185 
Liabilities
Other liabilities
Contingent consideration$ $ $ $ $— $— $193 $193 
Derivative liabilities (3)
Forward exchange contracts 293  293 — 338 — 338 
Written currency options 31  31 — — 
 324  324 — 345 — 345 
Total liabilities$ $324 $ $324 $— $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)    Balance at December 31, 2024 includes securities with an aggregate fair value of $81 million, 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 December 31, 2025 and 2024, Cash and cash equivalents included $13.8 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:
20252024
Fair value January 1$193 $354 
Changes in estimated fair value (1)
(52)(10)
Payments (2)
(141)(151)
Fair value December 31
$ $193 
(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 (ceftolozane and tazobactam) 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 and amount in 2024 also includes a $25 million payment related to the first commercial sale of Lyfnua (gefapixant) in the European Union.
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 December 31, 2025, was $45.6 billion compared with a carrying value of $49.3 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’s customers with the largest accounts receivable balances are: McKesson Corporation, Cencora, Inc. and Cardinal Health, Inc., which represented approximately 22%, 21% and 13%, respectively, of total accounts receivable at December 31, 2025. The Company monitors the creditworthiness of its customers to which it grants credit terms in the normal course of business. Bad debts have been minimal. The Company does not normally require collateral or other security to support credit sales.
The Company has accounts receivable factoring agreements with financial institutions in certain countries to sell accounts receivable. The Company factored $1.6 billion and $2.1 billion of accounts receivable as of December 31, 2025 and 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 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. At December 31, 2025 and 2024, the Company had collected $45 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 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 December 31, 2025 and 2024, respectively. The obligation to return such collateral is recorded in Accrued and other current liabilities.
v3.25.4
Inventories
12 Months Ended
Dec. 31, 2025
Inventory Disclosure [Abstract]  
Inventories Inventories
Inventories at December 31 consisted of:
20252024
Finished goods$2,275 $2,022 
Raw materials and work in process10,645 8,831 
Supplies331 289 

13,251 11,142 
Decrease to LIFO cost(912)(840)
 $12,339 $10,302 
Recognized as:
Inventories$6,658 $6,109 
Other Assets5,681 4,193 
Inventories valued under the LIFO method comprised approximately $4.3 billion and $3.4 billion at December 31, 2025 and 2024, respectively, after reflecting the decrease to LIFO cost. Amounts recognized as Other Assets are comprised almost entirely of raw materials and work in process inventories. At December 31, 2025 and 2024, these amounts included $5.5 billion and $3.8 billion, respectively, of inventories not expected to be sold within one year. In addition, these amounts included $211 million and $412 million at December 31, 2025 and 2024, respectively, of inventories produced in preparation for product launches.
v3.25.4
Goodwill and Other Intangibles
12 Months Ended
Dec. 31, 2025
Goodwill and Intangible Assets Disclosure [Abstract]  
Goodwill and Other Intangibles Goodwill and Other Intangibles
The following table summarizes goodwill activity by segment:
PharmaceuticalAnimal HealthTotal
Balance January 1, 2024
$17,922 $3,275 $21,197 
Acquisitions (1)
— 518 518 
Other (2)
(19)(28)(47)
Balance December 31, 2024 (3)
17,903 3,765 21,668 
Acquisitions (1)
 (106)(106)
Other (2)
2 15 17 
Balance December 31, 2025 (3)
$17,905 $3,674 $21,579 
(1)    Activity is related to the 2024 acquisition of the Elanco aqua business and related measurement period adjustments in 2025.
(2)    Includes cumulative translation adjustments on goodwill balances.
(3)    Accumulated goodwill impairment losses were $531 million at both December 31, 2025 and 2024.
Other acquired intangibles at December 31 consisted of:
 20252024
Gross
Carrying
Amount
Accumulated
Amortization
NetGross
Carrying
Amount
Accumulated
Amortization
Net
Product rights
$42,038 $20,710 $21,328 $29,988 $19,066 $10,922 
IPR&D427  427 430 — 430 
Trade names2,881 1,158 1,723 2,881 954 1,927 
Licenses and other10,064 6,861 3,203 8,863 5,772 3,091 
 $55,410 $28,729 $26,681 $42,162 $25,792 $16,370 
Some of the more significant acquired intangibles included in product rights, on a net basis, related to human health marketed products at December 31, 2025 were Ohtuvayre $11.8 billion; Winrevair, $5.4 billion; and Reblozyl, $2.5 billion. Additionally, the Company had $3.7 billion of net acquired intangibles related to animal health at December 31, 2025, of which $1.3 billion related to product rights and $1.7 billion was attributable to trade names, primarily related to Allflex. At December 31, 2025, IPR&D primarily relates to MK-1026 (nemtabrutinib), obtained through the 2020 acquisition of ArQule, Inc., which had a balance of $418 million. Some of the more significant net intangible assets included in licenses and other above at December 31, 2025 include Keytruda Qlex $886 million, related to a license agreement with Alteogen; Lynparza, $844 million, related to a collaboration with AstraZeneca;
Lenvima, $201 million, related to a collaboration with Eisai; and Adempas, $280 million, related to a collaboration with Bayer. See Note 3 for additional information related to the intangible asset associated with the license agreement and Note 4 for additional information related to the intangible assets associated with the collaborations.
IPR&D that the Company acquires through business combinations represents the fair value assigned to incomplete research projects which, at the time of acquisition, have not reached technological feasibility. Amounts capitalized as IPR&D are accounted for as indefinite-lived intangible assets, subject to impairment testing until completion or abandonment of the projects. Upon successful completion of each IPR&D project, the Company will make a separate determination as to the then-useful life of the asset and begin amortization.
In 2023, the Company recorded a $779 million IPR&D impairment charge within Research and development expenses related to MK-7264, gefapixant, a non-narcotic, oral selective P2X3 receptor antagonist, that was in development for the treatment of refractory or unexplained chronic cough in adults. In December 2023, the FDA issued a Complete Response Letter (CRL) regarding the resubmission of Merck’s New Drug Application (NDA) for gefapixant. In the CRL, the FDA concluded that Merck’s application did not meet substantial evidence of effectiveness for treating refractory chronic cough and unexplained chronic cough. The CRL was not related to the safety of gefapixant. The marketing application for gefapixant was based on results from the COUGH-1 and COUGH-2 clinical trials. In January 2022, the FDA issued a CRL regarding Merck’s original NDA for gefapixant. In that CRL, the FDA requested additional information related to the cough counting system that was used to assess efficacy. Receipt of the second CRL from the FDA constituted a triggering event that required the evaluation of the gefapixant intangible asset for impairment. The Company estimated the current fair value of gefapixant utilizing an income approach, which calculates the present value of projected future cash flows. The market participant assumptions used to derive the forecasted cash flows were updated to reflect revised market launch plans, resulting in a reduction in the estimated fair value. The revised estimated fair value of gefapixant when compared with its related carrying value resulted in the impairment charge noted above.
The IPR&D projects that remain in development are subject to the inherent risks and uncertainties in drug development and it is possible that the Company will not be able to successfully develop and complete the IPR&D programs and profitably commercialize the underlying product candidates.
The Company may recognize non-cash impairment charges in the future related to marketed products or pipeline programs and such charges could be material.
Aggregate amortization expense primarily recorded within Cost of sales was $2.8 billion in 2025, $2.4 billion in 2024 and $2.0 billion in 2023. The estimated aggregate amortization expense for each of the next five years is as follows: 2026, $3.8 billion; 2027, $3.6 billion; 2028, $3.3 billion; 2029, $3.0 billion; 2030, $2.7 billion.
v3.25.4
Loans Payable, Long-Term Debt and Leases
12 Months Ended
Dec. 31, 2025
Debt Disclosure [Abstract]  
Loans Payable, Long-Term Debt and Leases Loans Payable, Long-Term Debt and Leases
Loans Payable
Loans payable at December 31, 2025 included $2.3 billion of notes due in 2026, $215 million of long-dated notes that are subject to repayment at the option of the holders, and $63 million under a foreign financing facility. Loans payable at December 31, 2024 included $2.5 billion of notes due in 2025 and $149 million of long-dated notes that are subject to repayment at the option of the holders. The weighted-average interest rate of commercial paper borrowings was 4.32% and 5.18% for the years ended December 31, 2025 and 2024, respectively. There were no commercial paper borrowings outstanding at December 31, 2025 or 2024.
Long-Term Debt
Long-term debt at December 31 consisted of:
20252024
2.15% notes due 2031
$1,991 $1,989 
2.75% notes due 2051
1,981 1,980 
3.70% notes due 2045
1,981 1,980 
3.40% notes due 2029
1,744 1,742 
4.95% notes due 2035
1,739 — 
4.50% notes due 2033
1,553 1,509 
1.70% notes due 2027
1,498 1,497 
5.00% notes due 2053
1,492 1,482 
4.75% notes due 2035
1,486 — 
2.90% notes due 2061
1,485 1,484 
5.55% notes due 2055
1,477 — 
4.00% notes due 2049
1,475 1,474 
1.45% notes due 2030
1,242 1,240 
4.15% notes due 2043
1,241 1,240 
5.70% notes due 2055
1,235 — 
2.45% notes due 2050
1,217 1,216 
1.90% notes due 2028
997 996 
4.55% notes due 2032
995 — 
4.45% notes due 2032
994 — 
4.15% notes due 2031
994 — 
3.25% euro-denominated notes due 2032
993 880 
3.50% euro-denominated notes due 2037
990 877 
5.15% notes due 2063
988 987 
3.90% notes due 2039
988 987 
3.70% euro-denominated notes due 2044
988 876 
2.35% notes due 2040
987 986 
3.75% euro-denominated notes due 2054
985 873 
5.70% notes due 2065
984 — 
4.30% notes due 2030
747 746 
3.85% notes due 2027
747 — 
3.85% notes due 2029
746 — 
4.15% notes due 2030
745 — 
5.50% notes due 2046
742 — 
4.90% notes due 2044
740 740 
6.50% notes due 2033
698 702 
1.375% euro-denominated notes due 2036
583 517 
2.50% euro-denominated notes due 2034
583 517 
4.05% notes due 2028
499 498 
Floating rate notes due 2027 (1)
499 — 
Floating rate notes due 2029 (2)
498 — 
3.60% notes due 2042
493 492 
6.55% notes due 2037
402 404 
5.75% notes due 2036
339 339 
5.95% debentures due 2028
308 307 
5.85% notes due 2039
271 271 
6.40% debentures due 2028
251 251 
1.875% euro-denominated notes due 2026
 1,041 
0.75% notes due 2026
 998 
6.30% debentures due 2026
 135 
Other139 209 
$46,750 $34,462 
(1)    Floating rate is compounded SOFR plus 46 bps, which at December 31, 2025 was 4.16%.
(2)    Floating rate is compounded SOFR plus 57 bps, which at December 31, 2025 was 4.35%.
Other (as presented in the table above) includes borrowings at variable rates that resulted in effective interest rates of 4.18% and 5.02% for 2025 and 2024, respectively.
With the exception of the 6.30% debentures due 2026, the notes listed in the table above are redeemable in whole or in part, at Merck’s option at any time, at varying redemption prices. Effective as of November 3, 2009, the Company executed a full and unconditional guarantee of the then existing debt of its subsidiary Merck Sharp & Dohme Corp. (MSD, now Merck Sharp & Dohme LLC) and MSD executed a full and unconditional guarantee of the then existing debt of the Company (excluding commercial paper), including for payments of principal and interest. These guarantees do not extend to debt issued subsequent to that date.
In December 2025, the Company issued $8.0 billion aggregate principal amount of senior unsecured notes consisting of $500 million of floating rate notes due 2029, $750 million of 3.85% notes due 2029, $1.0 billion of 4.15% notes due 2031, $1.0 billion of 4.45% notes due 2032, $1.5 billion of 4.75% notes due 2035, $750 million of 5.50% notes due 2046, $1.5 billion of 5.55% notes due 2055, and $1.0 billion of 5.70% notes due 2065. The Company used the net proceeds from the offering for general corporate purposes, including to fund a portion of the approximately $9.2 billion cash consideration for the January 2026 acquisition of Cidara, including related fees and expenses (see Note 3).
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 from the offering for general corporate purposes, including to fund a portion of the $10.4 billion cash consideration for the October 2025 acquisition of Verona Pharma, including related fees and expenses (see Note 3).
In May 2024, MSD Netherlands Capital B.V., a wholly owned finance subsidiary of Merck, completed a registered public offering of €3.4 billion in aggregate principal amount of euro-dominated senior notes comprised of €850 million of 3.25% senior notes due 2032, €850 million of 3.50% senior notes due 2037, €850 million of 3.70% senior notes due 2044, and €850 million of 3.75% senior notes due 2054 (collectively, the Euronotes). The Company has fully and unconditionally guaranteed all of MSD Netherlands Capital B.V.’s obligations under the Euronotes and no other subsidiary of the Company will guarantee these obligations. MSD Netherlands Capital B.V. is a “finance subsidiary” as defined in Rule 13-01(a)(4)(vi) of Regulation S-X of the Exchange Act, with no assets or operations other than those related to the issuance, administration and repayment of the Euronotes. The financial condition, results of operations and cash flows of MSD Netherlands Capital B.V. are consolidated in the financial statements of the Company. The net cash proceeds from the offering were used for general corporate purposes.
Certain of the Company’s borrowings require that Merck comply with covenants and, at December 31, 2025, the Company was in compliance with these covenants.
The aggregate maturities of long-term debt for each of the next five years are as follows: 2026, $2.6 billion; 2027, $2.7 billion; 2028, $2.1 billion; 2029, $3.0 billion; 2030, $2.7 billion. Interest payments related to these debt obligations are as follows: 2026, $1.8 billion; 2027, $1.8 billion; 2028, $1.7 billion; 2029, $1.6 billion; 2030, $1.5 billion.
The Company has a $6.0 billion credit facility that matures in May 2030. The facility provides backup liquidity for the Company’s commercial paper borrowing facility and is to be used for general corporate purposes. The Company has not drawn funding from this facility.
Leases
The Company has operating leases primarily for manufacturing facilities, research and development facilities, corporate offices, employee housing, vehicles and certain equipment. The Company determines if an arrangement is a lease at inception. When evaluating contracts for embedded leases, the Company exercises judgment to determine if there is an explicit or implicit identified asset in the contract and if Merck controls the use of that asset. Embedded leases, primarily associated with contract manufacturing organizations, are immaterial. The lease term includes options to extend or terminate the lease when it is reasonably certain that Merck will exercise that option. Real estate leases for facilities have an average remaining lease term of approximately seven years, which include options to extend the lease term for periods ranging up to five years where applicable. Vehicle leases are generally in effect for four years. The Company elected to exclude short-term leases (leases with an initial term of 12 months or less) from the lease assets and liabilities on the balance sheet.
Lease expense for operating lease payments is recognized on a straight-line basis over the term of the lease. Operating lease assets and liabilities are recognized based on the present value of lease payments over the lease term. Since the Company’s leases do not have a readily determinable implicit discount rate, the Company uses
its incremental borrowing rate to calculate the present value of lease payments by asset class. On a quarterly basis, an updated incremental borrowing rate is determined based on the average remaining lease term of each asset class and the Company’s pretax cost of debt for that same term. The updated rates for each asset class are applied prospectively to new leases. The Company does not separate lease components (e.g., payments for rent, real estate taxes and insurance costs) from non-lease components (e.g. common-area maintenance costs) in the event that the agreement contains both. Merck includes both the lease and non-lease components for purposes of calculating the right-of-use asset and related lease liability (if the non-lease components are fixed). For vehicle leases and employee housing, the Company applies a portfolio approach to account for the operating lease assets and liabilities.
Certain of the Company’s lease agreements contain variable lease payments that are adjusted periodically for inflation or for actual operating expense true-ups compared with estimated amounts; however, these amounts are immaterial. Sublease income was immaterial and there were no sale and leaseback transactions in 2025. Merck’s lease agreements do not contain any material residual value guarantees or material restrictive covenants.
Operating lease cost was $423 million in 2025, $348 million in 2024 and $339 million in 2023. Cash paid for amounts included in the measurement of operating lease liabilities was $349 million in 2025, $357 million in 2024 and $347 million in 2023. Operating lease assets obtained in exchange for lease obligations were $162 million in 2025, $47 million in 2024 and $122 million in 2023.
Supplemental balance sheet information related to operating leases is as follows:
December 3120252024
Assets
Other Assets (1)
$1,507 $1,370 
Liabilities
Accrued and other current liabilities294 282 
Other Noncurrent Liabilities901 877 
$1,195 $1,159 
Weighted-average remaining lease term (years)7.06.0
Weighted-average discount rate3.5 %3.2 %
(1)    Includes prepaid leases that have no related lease liability.
Maturities of operating leases liabilities are as follows:
2026$335 
2027261 
2028204 
2029125 
2030103 
Thereafter415 
Total lease payments1,443 
Less: Imputed interest248 
$1,195 
At December 31, 2025, the Company had entered into additional real estate leases that had not yet commenced; the obligations associated with these leases total $400 million, of which $300 million relates to a lease that will commence in February 2026 and has a lease term of 20 years.
Loans Payable, Long-Term Debt and Leases Loans Payable, Long-Term Debt and Leases
Loans Payable
Loans payable at December 31, 2025 included $2.3 billion of notes due in 2026, $215 million of long-dated notes that are subject to repayment at the option of the holders, and $63 million under a foreign financing facility. Loans payable at December 31, 2024 included $2.5 billion of notes due in 2025 and $149 million of long-dated notes that are subject to repayment at the option of the holders. The weighted-average interest rate of commercial paper borrowings was 4.32% and 5.18% for the years ended December 31, 2025 and 2024, respectively. There were no commercial paper borrowings outstanding at December 31, 2025 or 2024.
Long-Term Debt
Long-term debt at December 31 consisted of:
20252024
2.15% notes due 2031
$1,991 $1,989 
2.75% notes due 2051
1,981 1,980 
3.70% notes due 2045
1,981 1,980 
3.40% notes due 2029
1,744 1,742 
4.95% notes due 2035
1,739 — 
4.50% notes due 2033
1,553 1,509 
1.70% notes due 2027
1,498 1,497 
5.00% notes due 2053
1,492 1,482 
4.75% notes due 2035
1,486 — 
2.90% notes due 2061
1,485 1,484 
5.55% notes due 2055
1,477 — 
4.00% notes due 2049
1,475 1,474 
1.45% notes due 2030
1,242 1,240 
4.15% notes due 2043
1,241 1,240 
5.70% notes due 2055
1,235 — 
2.45% notes due 2050
1,217 1,216 
1.90% notes due 2028
997 996 
4.55% notes due 2032
995 — 
4.45% notes due 2032
994 — 
4.15% notes due 2031
994 — 
3.25% euro-denominated notes due 2032
993 880 
3.50% euro-denominated notes due 2037
990 877 
5.15% notes due 2063
988 987 
3.90% notes due 2039
988 987 
3.70% euro-denominated notes due 2044
988 876 
2.35% notes due 2040
987 986 
3.75% euro-denominated notes due 2054
985 873 
5.70% notes due 2065
984 — 
4.30% notes due 2030
747 746 
3.85% notes due 2027
747 — 
3.85% notes due 2029
746 — 
4.15% notes due 2030
745 — 
5.50% notes due 2046
742 — 
4.90% notes due 2044
740 740 
6.50% notes due 2033
698 702 
1.375% euro-denominated notes due 2036
583 517 
2.50% euro-denominated notes due 2034
583 517 
4.05% notes due 2028
499 498 
Floating rate notes due 2027 (1)
499 — 
Floating rate notes due 2029 (2)
498 — 
3.60% notes due 2042
493 492 
6.55% notes due 2037
402 404 
5.75% notes due 2036
339 339 
5.95% debentures due 2028
308 307 
5.85% notes due 2039
271 271 
6.40% debentures due 2028
251 251 
1.875% euro-denominated notes due 2026
 1,041 
0.75% notes due 2026
 998 
6.30% debentures due 2026
 135 
Other139 209 
$46,750 $34,462 
(1)    Floating rate is compounded SOFR plus 46 bps, which at December 31, 2025 was 4.16%.
(2)    Floating rate is compounded SOFR plus 57 bps, which at December 31, 2025 was 4.35%.
Other (as presented in the table above) includes borrowings at variable rates that resulted in effective interest rates of 4.18% and 5.02% for 2025 and 2024, respectively.
With the exception of the 6.30% debentures due 2026, the notes listed in the table above are redeemable in whole or in part, at Merck’s option at any time, at varying redemption prices. Effective as of November 3, 2009, the Company executed a full and unconditional guarantee of the then existing debt of its subsidiary Merck Sharp & Dohme Corp. (MSD, now Merck Sharp & Dohme LLC) and MSD executed a full and unconditional guarantee of the then existing debt of the Company (excluding commercial paper), including for payments of principal and interest. These guarantees do not extend to debt issued subsequent to that date.
In December 2025, the Company issued $8.0 billion aggregate principal amount of senior unsecured notes consisting of $500 million of floating rate notes due 2029, $750 million of 3.85% notes due 2029, $1.0 billion of 4.15% notes due 2031, $1.0 billion of 4.45% notes due 2032, $1.5 billion of 4.75% notes due 2035, $750 million of 5.50% notes due 2046, $1.5 billion of 5.55% notes due 2055, and $1.0 billion of 5.70% notes due 2065. The Company used the net proceeds from the offering for general corporate purposes, including to fund a portion of the approximately $9.2 billion cash consideration for the January 2026 acquisition of Cidara, including related fees and expenses (see Note 3).
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 from the offering for general corporate purposes, including to fund a portion of the $10.4 billion cash consideration for the October 2025 acquisition of Verona Pharma, including related fees and expenses (see Note 3).
In May 2024, MSD Netherlands Capital B.V., a wholly owned finance subsidiary of Merck, completed a registered public offering of €3.4 billion in aggregate principal amount of euro-dominated senior notes comprised of €850 million of 3.25% senior notes due 2032, €850 million of 3.50% senior notes due 2037, €850 million of 3.70% senior notes due 2044, and €850 million of 3.75% senior notes due 2054 (collectively, the Euronotes). The Company has fully and unconditionally guaranteed all of MSD Netherlands Capital B.V.’s obligations under the Euronotes and no other subsidiary of the Company will guarantee these obligations. MSD Netherlands Capital B.V. is a “finance subsidiary” as defined in Rule 13-01(a)(4)(vi) of Regulation S-X of the Exchange Act, with no assets or operations other than those related to the issuance, administration and repayment of the Euronotes. The financial condition, results of operations and cash flows of MSD Netherlands Capital B.V. are consolidated in the financial statements of the Company. The net cash proceeds from the offering were used for general corporate purposes.
Certain of the Company’s borrowings require that Merck comply with covenants and, at December 31, 2025, the Company was in compliance with these covenants.
The aggregate maturities of long-term debt for each of the next five years are as follows: 2026, $2.6 billion; 2027, $2.7 billion; 2028, $2.1 billion; 2029, $3.0 billion; 2030, $2.7 billion. Interest payments related to these debt obligations are as follows: 2026, $1.8 billion; 2027, $1.8 billion; 2028, $1.7 billion; 2029, $1.6 billion; 2030, $1.5 billion.
The Company has a $6.0 billion credit facility that matures in May 2030. The facility provides backup liquidity for the Company’s commercial paper borrowing facility and is to be used for general corporate purposes. The Company has not drawn funding from this facility.
Leases
The Company has operating leases primarily for manufacturing facilities, research and development facilities, corporate offices, employee housing, vehicles and certain equipment. The Company determines if an arrangement is a lease at inception. When evaluating contracts for embedded leases, the Company exercises judgment to determine if there is an explicit or implicit identified asset in the contract and if Merck controls the use of that asset. Embedded leases, primarily associated with contract manufacturing organizations, are immaterial. The lease term includes options to extend or terminate the lease when it is reasonably certain that Merck will exercise that option. Real estate leases for facilities have an average remaining lease term of approximately seven years, which include options to extend the lease term for periods ranging up to five years where applicable. Vehicle leases are generally in effect for four years. The Company elected to exclude short-term leases (leases with an initial term of 12 months or less) from the lease assets and liabilities on the balance sheet.
Lease expense for operating lease payments is recognized on a straight-line basis over the term of the lease. Operating lease assets and liabilities are recognized based on the present value of lease payments over the lease term. Since the Company’s leases do not have a readily determinable implicit discount rate, the Company uses
its incremental borrowing rate to calculate the present value of lease payments by asset class. On a quarterly basis, an updated incremental borrowing rate is determined based on the average remaining lease term of each asset class and the Company’s pretax cost of debt for that same term. The updated rates for each asset class are applied prospectively to new leases. The Company does not separate lease components (e.g., payments for rent, real estate taxes and insurance costs) from non-lease components (e.g. common-area maintenance costs) in the event that the agreement contains both. Merck includes both the lease and non-lease components for purposes of calculating the right-of-use asset and related lease liability (if the non-lease components are fixed). For vehicle leases and employee housing, the Company applies a portfolio approach to account for the operating lease assets and liabilities.
Certain of the Company’s lease agreements contain variable lease payments that are adjusted periodically for inflation or for actual operating expense true-ups compared with estimated amounts; however, these amounts are immaterial. Sublease income was immaterial and there were no sale and leaseback transactions in 2025. Merck’s lease agreements do not contain any material residual value guarantees or material restrictive covenants.
Operating lease cost was $423 million in 2025, $348 million in 2024 and $339 million in 2023. Cash paid for amounts included in the measurement of operating lease liabilities was $349 million in 2025, $357 million in 2024 and $347 million in 2023. Operating lease assets obtained in exchange for lease obligations were $162 million in 2025, $47 million in 2024 and $122 million in 2023.
Supplemental balance sheet information related to operating leases is as follows:
December 3120252024
Assets
Other Assets (1)
$1,507 $1,370 
Liabilities
Accrued and other current liabilities294 282 
Other Noncurrent Liabilities901 877 
$1,195 $1,159 
Weighted-average remaining lease term (years)7.06.0
Weighted-average discount rate3.5 %3.2 %
(1)    Includes prepaid leases that have no related lease liability.
Maturities of operating leases liabilities are as follows:
2026$335 
2027261 
2028204 
2029125 
2030103 
Thereafter415 
Total lease payments1,443 
Less: Imputed interest248 
$1,195 
At December 31, 2025, the Company had entered into additional real estate leases that had not yet commenced; the obligations associated with these leases total $400 million, of which $300 million relates to a lease that will commence in February 2026 and has a lease term of 20 years.
v3.25.4
Contingencies and Environmental Liabilities
12 Months Ended
Dec. 31, 2025
Commitments and Contingencies Disclosure [Abstract]  
Contingencies and Environmental Liabilities Contingencies and Environmental Liabilities
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 December 31, 2025, approximately 610 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 December 31, 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, May 1, 2025, and July 11, 2025, plaintiff’s co-lead counsel in the Gardasil MDL filed multi-plaintiff complaints in New Jersey state court. Merck removed the cases 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. The U.S. Judicial Panel on Multidistrict Litigation issued orders transferring the cases to the Gardasil MDL.
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 May 4, 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 Demands
As previously disclosed, in August 2025, the Company received a Civil Investigative Demand (CID) from the U.S. Department of Justice (DOJ), pursuant to a False Claims Act investigation, seeking documents, information, and testimony related to the Company’s programs and practices concerning diversity, equity, and inclusion. The CID states that the DOJ is investigating whether, in connection with the Company’s claims for payments under its federal contracts, the Company falsely certified compliance with federal antidiscrimination laws. The Company is cooperating with the investigation.
As previously disclosed, in June 2024, Merck received a Civil Investigative Demand (CID) from the DOJ, pursuant to a False Claims Act investigation, seeking documents and materials related to Steglatro, Januvia and certain related drugs. The CID states that it is investigating Merck’s price reporting under the Medicaid Drug Rebate Program as well as compliance with anti-kickback requirements in connection with patient assistance programs. The Company is cooperating with the investigation.
As previously disclosed, in June 2020, Merck received a CID from the DOJ. The CID requested answers to interrogatories, as well as various documents, regarding temperature excursions at a third-party storage facility containing certain Merck products. Merck cooperated with the government’s investigation. The government has ended its investigation and the matter is now closed.
Inflation Reduction Act
As previously disclosed, in June 2023, Merck filed a complaint in the U.S. District Court for the District of Columbia against the U.S. government regarding the Inflation Reduction Act’s “Drug Price Negotiation Program” for Medicare (the Program). This litigation seeks relief from the Program by challenging its constitutionality as violative of the First and Fifth Amendments to the U.S. Constitution.
Other Matters
As previously disclosed, in April 2019, Merck received a set of investigative interrogatories from the California Attorney General’s Office pursuant to its investigation of conduct and agreements that allegedly affected or delayed competition to Lantus in the insulin market. The interrogatories seek information concerning Merck’s development of an insulin glargine product, and its subsequent termination, as well as Merck’s patent litigation against Sanofi S.A. concerning Lantus and the resolution of that litigation. Merck is cooperating with the California Attorney General’s investigation.
As previously disclosed, from time to time, the Company’s subsidiaries in China receive inquiries regarding their operations from various Chinese governmental agencies. Some of these inquiries may be related to matters involving other multinational pharmaceutical companies, as well as Chinese entities doing business with such companies. The Company’s policy is to cooperate with these authorities and to provide responses as appropriate.
As previously disclosed, from time to time, the Company receives inquiries and is the subject of preliminary investigation activities from competition and other governmental authorities in markets outside the U.S. These authorities may include regulators, administrative authorities, and law enforcement and other similar officials, and these preliminary investigation activities may include site visits, formal or informal requests or demands for documents or materials, inquiries or interviews and similar matters. Certain of these preliminary inquiries or activities may lead to the commencement of formal proceedings. Should those proceedings be determined adversely to the Company, monetary fines and/or remedial undertakings may be required.
Securities Litigation
As previously disclosed, on February 12, 2025, a putative class action was filed against Merck and certain of its officers in the U.S. District Court for the District of New Jersey, captioned Cronin v. Merck & Co., Inc., et al.,
purportedly on behalf of all purchasers of Merck common stock between October 26, 2023 and February 3, 2025. Plaintiff alleges that Merck violated federal securities laws by making materially false and misleading statements and 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 December 4, 2025, the court entered an order approving appointment of a lead plaintiff group comprised of purported Merck shareholders AMF Tjänstepension AB, KBC Asset Management NV, and Wayne County Employees’ Retirement System (Lead Plaintiffs). On December 17, 2025, the court approved the parties’ joint stipulation and scheduling order setting the deadline to file an operative amended complaint and motion-to-dismiss briefing. Per the stipulation, Lead Plaintiffs’ amended complaint was filed on February 20, 2026; defendants’ motion to dismiss is due May 1, 2026; Lead Plaintiffs’ opposition to the motion to dismiss is due June 30, 2026; and defendants’ reply brief is due August 14, 2026.
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 a violation of Section 14(a) of the Securities Exchange Act of 1934 (the Exchange Act), as well as claims of 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.
As previously disclosed, 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.
As previously disclosed, 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 and consolidation stipulations. The cases are now consolidated and stayed under the caption In re Merck & Co., Inc. Stockholder Derivative Litigation.
As previously disclosed, 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.
On November 3, 2025, purported Merck shareholder The Vladimir Gusinsky Revocable Trust filed a derivative lawsuit in the Superior Court of New Jersey (Union County), captioned The Vladimir Gusinsky Revocable Trust v. Frazier, et al., against certain current and former Merck officers and board members. The complaint asserts claims of breach of fiduciary duty and unjust enrichment based on the same allegations as the putative securities class action and the earlier-filed derivative lawsuits. On behalf of the Company, the complaint seeks unspecified monetary damages, corporate governance reforms, restitution, disgorgement of profits, and fees and costs.
On November 17, 2025, the parties to the Weniger and Gusinsky derivative lawsuits filed a joint stipulation to stay the proceedings 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 stipulated to consolidate the Weniger and Gusinsky derivative lawsuits. On November 18, 2025, the court approved the parties’ stipulation to consolidate the Weniger and Gusinsky lawsuits. On December 4, 2025, the parties filed a joint status letter with a renewed request for a stay.
On December 5, 2025, purported Merck shareholder Mark Kistenmacher filed a derivative lawsuit in the Superior Court of New Jersey (Union County), captioned Kistenmacher v. Baker, et al., against certain current and former Merck officers and board members. The complaint asserts claims of breach of fiduciary duty, unjust enrichment, waste of corporate assets, gross mismanagement, and abuse of control based on the same allegations
as the putative securities class action and the earlier-filed derivative lawsuits. On behalf of the Company, the complaint seeks unspecified monetary damages, disgorgement of profits and special benefits, punitive damages, 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.
As previously disclosed, 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.
As previously disclosed, 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 February 12, 2026, the district court in the Northern District of California granted in part and denied in part the motion to dismiss in the Kaiser case.
RotaTeq Antitrust Litigation
As previously disclosed, in March 2023, the Mayor and City Council of Baltimore filed a putative class action against MSD in the Eastern District of Pennsylvania on behalf of all third-party payers in states that indirectly purchased, paid, and/or provided reimbursement for some or all of the purchase price of RotaTeq (Rotavirus Vaccine, Live Oral, Pentavalent), other than for resale, from March 3, 2019 to the present. Plaintiff alleges that MSD violated federal and state antitrust laws and state consumer protection laws. Plaintiff alleges that MSD has implemented an anticompetitive vaccine bundling scheme whereby MSD leverages its alleged monopoly power in certain pediatric vaccine markets to maintain its alleged monopoly power in the U.S. market for rotavirus vaccines in order to charge supracompetitive prices for RotaTeq. Plaintiff seeks permanent injunctive relief and unspecified monetary damages on purchases of RotaTeq, trebled, and fees and costs. In May 2023, MSD moved to dismiss the complaint. In November 2023, the court granted in part and denied in part the motion to dismiss, dismissing plaintiff’s Idaho and Utah consumer law claims and allowing all other claims to proceed.
Bravecto Litigation
As previously disclosed, in January 2020, the Company was served with a complaint in the U.S. District Court for the District of New Jersey. Following motion practice, the plaintiffs filed a third amended complaint in August 2024, seeking to certify a nationwide class as well as five statewide classes of purchasers or users of Bravecto (fluralaner) products from its launch through the present. Plaintiffs contend Bravecto causes neurological events in dogs and cats and alleges violations of the consumer fraud statutes of certain of their home states (Connecticut, New York, Florida and Texas), Breach of Warranty, Product Liability, and related theories. The Company moved to dismiss or, alternatively, to strike the class allegations from the third amended complaint, and that motion was granted in part and denied in part. The Company sought permission from the court to file a motion for summary judgment directed at the named plaintiffs’ claims and that motion is pending. The Company anticipates that plaintiffs will file a motion for class certification in March 2026 and that it will oppose plaintiffs’ motion thereafter. A similar case was filed in Quebec, Canada in May 2019. The Superior Court certified a class of dog owners in Quebec who gave Bravecto Chew to their dogs between February 16, 2017 and November 2, 2018 whose dogs experienced one of the conditions in the post-marketing adverse reactions section of the labeling approved on November 2, 2018. The Company and plaintiffs each appealed the class certification decision. The Court of Appeal of Quebec amended the class period to start July 2,
2014, allowed the second plaintiff to serve as a class representative, and modified the list of conditions in the class definition. The Company sought leave to appeal to the Supreme Court of Canada, which was denied. The case is proceeding in the Superior Court.
Merck KGaA Litigation
As previously disclosed, in January 2016, to protect its long-established brand rights in the U.S., the Company filed a lawsuit against Merck KGaA, Darmstadt, Germany (KGaA), historically operating as the EMD Group in the U.S., alleging it improperly uses the name “Merck” in the U.S. KGaA has filed suit against the Company in a number of jurisdictions outside of the U.S. alleging, among other things, unfair competition, trademark infringement and/or corporate name infringement. In certain of those jurisdictions, KGaA also alleges breach of the parties’ coexistence agreement. The litigation is ongoing in the U.S. with no trial date set, and also ongoing in jurisdictions outside of the U.S.
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, potentially significant intangible asset impairment charges. In addition to these matters, the Company may be involved in other litigation involving its intellectual property and intellectual property owned or licensed by other companies.
Bridion As previously disclosed, between January and November 2020, the Company received multiple Paragraph IV Certification Letters under the Hatch-Waxman Act notifying the Company that generic drug companies had filed applications to the FDA seeking pre-patent expiry approval to sell generic versions of Bridion (sugammadex) Injection. In March, April and December 2020, the Company filed patent infringement lawsuits against those generic companies. The defendants in the New Jersey action referred to below stipulated to infringement of the asserted claims and withdrew all remaining claims and defenses other than a defense seeking to shorten the patent term extension (PTE) of the sugammadex patent to December 2022. The U.S. District Court for the District of New Jersey held a one-day trial in December 2022 on this remaining PTE calculation defense.
As previously disclosed, in June 2023, the U.S. District Court for the District of New Jersey ruled in Merck’s favor. The court held that Merck’s calculation of PTE for the sugammadex patent covering the compound is not invalid and that the U.S. Patent & Trademark Office correctly granted a full five-year extension. Also in June 2023, the U.S. District Court for the District of New Jersey issued a final judgment prohibiting the FDA from approving any of the pending or tentatively approved generic applications until January 27, 2026, except for any subsequent agreements between defendants and Merck or further order by the court. In March 2025, the Federal Circuit affirmed the district court’s decision, holding that the patent term extension granted to the sugammadex patent covering Bridion was not invalid and that the patent is entitled to its full five-year patent term extension. In addition, the FDA has now granted Bridion six months of pediatric exclusivity.
While the New Jersey action was pending, the Company settled with five generic companies providing that these generic companies can bring their generic versions of Bridion to the market in January 2026 (which were subject to delay by any applicable pediatric exclusivity) or earlier under certain circumstances. Thus, the Federal Circuit’s decision and these settlements secure Bridion’s exclusivity in the U.S. through July 27, 2026.
Januvia, Janumet, Janumet XR As previously disclosed, the FDA granted pediatric exclusivity with respect to Januvia (sitagliptin), Janumet (sitagliptin/metformin HCl), 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.
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 the FDA has approved a non-automatically substitutable form of sitagliptin that differs from the form in the Company’s sitagliptin products.
In March 2024, the Company received another Paragraph IV Certification Letter under the Hatch-Waxman Act from Azurity Pharmaceuticals, Inc. (Azurity) asserting that a different sitagliptin product subject to its ANDA does not infringe the salt/polymorph patent. In May 2024, Merck filed a civil action in the U.S. District Court of Delaware alleging infringement. The case was dismissed without prejudice in July 2024. Following the dismissal, the Company granted Azurity a covenant not to assert the salt/polymorph patent against the Azurity product that is the subject of such ANDA.
Supplementary Protection Certificates (SPCs) for Janumet expired in April 2023 for the majority of European countries. Prior to expiration, generic companies sought revocation of the Janumet SPCs in a number of European countries. In February 2022, a Finnish court referred certain questions to the Court of Justice of the European Union that could impact the validity of the Janumet SPCs in Europe. A decision rendered in December 2024 provides guidance on points of law and does not directly apply to the Janumet SPCs. Thus, additional proceedings in certain countries where generic companies were prevented from launching products during the SPC period may be necessary to determine whether the SPCs are valid and if not, whether damages are appropriate. Those countries include Belgium, Czech Republic, Finland, and France. If the Janumet SPCs are ultimately upheld, the Company has reserved its rights related to the pursuit of damages for those countries where a generic launched prior to expiry of the Janumet SPC.
In October 2023, the Company filed a patent infringement lawsuit against Sawai Pharmaceuticals Co., Ltd. (Sawai) and Medisa Shinyaku Co., Ltd (collectively, Defendants) in the Tokyo District Court seeking an injunction to stop the manufacture, sale and offer for sale of the Defendants’ sitagliptin dihydrogen phosphate product, while the Company’s patents and patent term extensions are in force. The lawsuit is in response to the Defendants’ application for marketing authorization to sell a generic sitagliptin dihydrogen phosphate product, in the anhydride form, which was approved in August 2023. Merck asserts that the Defendants’ activity infringes a patent term extension associated with Merck’s patent directed to the sitagliptin compound patent. In January 2026, the Tokyo District Court orally indicated its view that the extended patent covers Sawai’s tablets. Following this, Sawai conceded to all of the Company’s claims; thus, the case was concluded without a written decision. The relevant PTE for Januvia in Japan remains in effect until it expires on March 30, 2026.
Keytruda As previously disclosed, in November 2022, the Company filed a complaint against The Johns Hopkins University (JHU) in the U.S. District Court of Maryland. This action concerns a joint research collaboration between Merck and JHU regarding the use of Keytruda in certain indications. Merck and JHU partnered to design and conduct a clinical study administering Keytruda to cancer patients having tumors that had the genetic biomarker known as microsatellite instability-high (MSI-H) (the Joint Clinical Study). Subsequently JHU obtained a number of U.S. patents specifically relying on the Joint Clinical Study. Merck alleges that JHU breached the collaboration agreement by obtaining issuance of these patents without informing or involving Merck, which were licensed to others, and then trying to enforce these patents against Merck. Merck therefore brought an action for breach of contract, declaratory judgment of noninfringement, and promissory estoppel. JHU answered the complaint in April and May 2023, denying Merck’s claims, and counterclaiming for willful infringement of nine issued U.S. patents, including a demand for damages. Between November 30, 2023 and March 13, 2024, the Company filed inter partes review petitions with the U.S. Patent Office’s Patent Trial and Appeal Board (PTAB), challenging the patentability of all nine patents asserted in the district court. Between June 2024 and October 2024, the PTAB instituted a review of all nine challenged patents. In June 2024, the district court granted Merck’s motion to stay the case in its entirety pending the outcome of the PTAB proceeding instituted in June 2024.
Between June and November of 2025, the PTAB issued Final Written Decisions finding all challenged claims of the nine patents unpatentable. JHU has filed notices of appeal to the Federal Circuit Court of Appeals. The district court’s stay is expected to continue until at least the issuance of the Federal Circuit decision.
Lenvima Between 2019 and 2024, Eisai Inc (Eisai) received Paragraph IV Certification Letters under the Hatch-Waxman Act, providing notice that Sun Pharmaceuticals (Sun), Shilpa Medicare Ltd. (Shilpa), Dr. Reddy’s Laboratories (DRL), and Torrent Pharmaceuticals (Torrent) filed separate applications to the FDA seeking pre-patent expiry approval to sell generic versions of Lenvima (lenvatinib) tablets. Between 2019 and 2024, Eisai and the Company filed a series of patent infringement lawsuits in the U.S. District Court for the District of New Jersey against
each generic company asserting several Orange-Book listed patents. The Lenvima compound patent expires in April 2026 (including pediatric exclusivity) and was not challenged. Eisai and the Company settled with Sun, DRL, and Torrent regarding the remaining asserted patents covering Lenvima. Eisai has announced publicly, these generic companies can bring their generic versions of Lenvima to the market in the U.S. in July 2030 or earlier under certain circumstances. In May 2025, Eisai and the Company received a favorable trial decision against Shilpa from the U.S. District Court for the District of New Jersey. As a result of the decision, Shilpa is unable to receive approval from the FDA to sell its generic version of Lenvima until February 2036. Shilpa has appealed the district court’s decision to the U.S. Court of Appeals for the Federal Circuit, and the appeal is currently pending.
Subcutaneous Pembrolizumab As previously disclosed, Halozyme, Inc. (Halozyme) has publicly alleged that certain patents in its modified hyaluronidase (MDASE) portfolio cover an ingredient in the Company’s subcutaneous pembrolizumab product. In November 2024, the Company began filing a series of post grant review (PGR) petitions before the PTAB alleging that certain patents in the MDASE portfolio are invalid. In June 2025, the PTAB instituted the first petition filed by the Company. Since then, the PTAB also instituted 13 additional petitions. An institution decision on one additional patent in the MDASE portfolio is still pending.
In April 2025, Halozyme filed a complaint in the U.S. District Court for the District of New Jersey alleging that the Company’s activities related to subcutaneous pembrolizumab infringe or will infringe 15 patents belonging to the MDASE portfolio, 12 of which are the subject of the Company’s already filed PGR petitions. 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 in the UK, France, Germany and The Netherlands. Halozyme counterclaimed for an injunction in the UK under the ‘622 patent as well as an additional patent but have undertaken not to enforce any injunction there until the validity of both patents, which is in dispute, is finally determined. In October 2025, the Company accepted service of a preliminary injunction filed by Halozyme under the ‘622 patent in Germany. Following a one day hearing in December 2025, a preliminary injunction was awarded against the Company prohibiting sales in Germany. The Company has appealed the preliminary injunction decision and expects a decision on the appeal in the second quarter of 2026.
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 As previously disclosed, in September 2025, Pogona, LLC filed a complaint in the U.S. District Court for the District of New Jersey alleging that the Company’s activities related to Capvaxive infringe U.S. Patent No. 11,058,757. 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 December 31, 2025 and 2024 of approximately $245 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.
Environmental Matters
The Company and its subsidiaries are parties to a number of proceedings brought under the Comprehensive Environmental Response, Compensation and Liability Act, commonly known as Superfund, and other federal and state equivalents. These proceedings seek to require the operators of hazardous waste disposal facilities, transporters of waste to the sites and generators of hazardous waste disposed of at the sites to clean up the sites or to reimburse the government for cleanup costs. The Company has been made a party to these proceedings as an alleged generator of waste disposed of at the sites. In each case, the government alleges that the defendants are jointly and severally liable for the cleanup costs. Although joint and several liability is alleged, these proceedings are frequently resolved so that the allocation of cleanup costs among the parties more nearly reflects the relative contributions of the parties to the site situation. The Company’s potential liability varies greatly from site to site. For some sites the potential liability is de minimis and for others the final costs of cleanup have not yet been determined. While it is not feasible to predict the outcome of many of these proceedings brought by federal or state agencies or private litigants, in the opinion of the Company, such proceedings should not ultimately result in any liability which would have a material adverse effect on the financial condition, results of operations or liquidity of the Company. The Company has taken an active role in identifying and accruing for these costs and such amounts do not include any reduction for anticipated recoveries of cleanup costs from former site owners or operators or other recalcitrant potentially responsible parties.
In management’s opinion, the liabilities for all environmental matters that are probable and reasonably estimable have been accrued and totaled $42 million and $41 million at December 31, 2025 and 2024, respectively. These liabilities are undiscounted, do not consider potential recoveries from other parties and will be paid out over the periods of remediation for the applicable sites, which are expected to occur primarily over the next 15 years. Although it is not possible to predict with certainty the outcome of these matters, or the ultimate costs of remediation, management does not believe that any reasonably possible expenditures that may be incurred in excess of the liabilities accrued should exceed approximately $58 million in the aggregate. Management also does not believe that these expenditures should result in a material adverse effect on the Company’s financial condition, results of operations or liquidity for any year.
v3.25.4
Equity
12 Months Ended
Dec. 31, 2025
Equity [Abstract]  
Equity Equity
The Merck certificate of incorporation authorizes 6,500,000,000 shares of common stock and 20,000,000 shares of preferred stock.
Capital Stock
A summary of common stock and treasury stock transactions (shares in millions) is as follows:
 202520242023
  Common
Stock
Treasury
Stock
Common
Stock
Treasury
Stock
Common
Stock
Treasury
Stock
Balance January 13,577 1,049 3,577 1,045 3,577 1,039 
Purchases of treasury stock 59 — 11 — 13 
Issuances (1)
 (6)— (7)— (7)
Balance December 313,577 1,102 3,577 1,049 3,577 1,045 
(1)    Issuances primarily reflect activity under share-based compensation plans.
v3.25.4
Share-Based Compensation Plans
12 Months Ended
Dec. 31, 2025
Share-Based Payment Arrangement [Abstract]  
Share-Based Compensation Plans Share-Based Compensation Plans
The Company has share-based compensation plans under which the Company grants restricted stock units (RSUs) and performance share units (PSUs) to certain management level employees. In addition, employees
and non-employee directors may be granted options to purchase shares of Company common stock at the fair market value at the time of grant. These plans were approved by the Company’s shareholders.
At December 31, 2025, 66 million shares collectively were authorized for future grants under the Company’s share-based compensation plans. These awards are settled with treasury shares.
Employee stock options are granted to purchase shares of Company stock at the fair market value at the time of grant. These awards generally vest one-third each year over a three-year period, with a contractual term of 7-10 years. RSUs are stock awards that are granted to employees and entitle the holder to shares of common stock as the awards vest. The fair value of the stock option and RSU awards is determined and fixed on the grant date based on the Company’s stock price. PSUs are stock awards where the ultimate number of shares issued will be contingent on the Company’s performance against a pre-set objective or set of objectives. The fair value of each PSU is determined on the date of grant based on the Company’s stock price. For RSUs and PSUs, dividends declared during the vesting period are payable to the employees only upon vesting. Over the PSU performance period, the number of shares of stock that are expected to be issued will be adjusted based on the probability of achievement of a performance target and final compensation expense will be recognized based on the ultimate number of shares issued. RSU and PSU distributions will be in shares of Company stock after the end of the vesting or performance period, subject to the terms applicable to such awards. PSU awards generally vest after three years. RSU awards generally vest one-third each year over a three-year period.
Total pretax share-based compensation cost recorded in 2025, 2024 and 2023 was $820 million, $761 million and $645 million, respectively. Income tax benefits for share-based compensation expense recognized in 2025, 2024 and 2023 were $125 million, $117 million and $96 million, respectively.
The Company uses the Black-Scholes option pricing model for determining the fair value of option grants. In applying this model, the Company uses both historical data and current market data to estimate the fair value of its options. The Black-Scholes model requires several assumptions including expected dividend yield, risk-free interest rate, volatility, and term of the options. The expected dividend yield is based on historical patterns of dividend payments. The risk-free interest rate is based on the rate at grant date of zero-coupon U.S. Treasury Notes with a term equal to the expected term of the option. Expected volatility is estimated using a blend of historical and implied volatility. The historical component is based on historical monthly price changes. The implied volatility is obtained from market data on the Company’s traded options. The expected life represents the amount of time that options granted are expected to be outstanding, based on historical and forecasted exercise behavior.
The weighted average exercise price of options granted in 2025, 2024 and 2023 was $84.71, $129.22 and $117.89 per option, respectively. The weighted average fair value of options granted in 2025, 2024 and 2023 was $18.61, $25.60 and $21.69 per option, respectively, and were determined using the following assumptions:
Years Ended December 31202520242023
Expected dividend yield3.1 %3.0 %3.1 %
Risk-free interest rate3.9 %4.7 %3.4 %
Expected volatility25.9 %20.5 %22.4 %
Expected life (years)5.85.85.8
Summarized information relative to stock option plan activity (options in thousands) is as follows:
Number
of Options
Weighted
Average
Exercise
Price
Weighted
Average
Remaining
Contractual
Term (Years)
Aggregate
Intrinsic
Value
Outstanding January 1, 2025
12,500 $86.04 
Granted1,616 84.71 
Exercised(1,428)64.76 
Forfeited(211)106.46   
Outstanding December 31, 2025
12,477 $87.95 5.7$275 
Vested and expected to vest December 31, 202512,235 $87.73 5.7$272 
Exercisable December 31, 20259,348 $82.09 4.8$244 
Additional information pertaining to stock option plans is provided in the table below:
Years Ended December 31202520242023
Total intrinsic value of stock options exercised$41 $144 $95 
Fair value of stock options vested36 32 30 
Cash received from the exercise of stock options92 177 125 
A summary of nonvested RSU and PSU activity (shares in thousands) is as follows:
 RSUsPSUs
  Number
of Shares
Weighted
Average
Grant Date
Fair Value
Number
of Shares
Weighted
Average
Grant Date
Fair Value
Nonvested January 1, 2025
12,232 $117.94 1,766 $117.57 
Granted10,318 84.65 1,233 81.20 
Vested(6,042)110.84 (1,101)88.42 
Forfeited(786)104.44 (64)104.87 
Nonvested December 31, 202515,722 $99.50 1,834 $111.13 
Expected to vest December 31, 202513,978 $100.27 1,732 $111.82 
At December 31, 2025, there was $1.1 billion of total pretax unrecognized compensation expense related to nonvested stock options, RSU and PSU awards which will be recognized over a weighted average period of 1.9 years. For segment reporting, share-based compensation costs are unallocated expenses.
v3.25.4
Pension and Other Postretirement Benefit Plans
12 Months Ended
Dec. 31, 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. In addition, the Company provides medical benefits, principally to its eligible U.S. retirees and their dependents, through its other postretirement benefit plans. The Company uses December 31 as the year-end measurement date for all of its pension plans and other postretirement benefit plans.
Net Periodic Benefit Cost
The net periodic benefit cost (credit) for pension and other postretirement benefit plans consisted of the following components:
Pension Benefits
U.S.InternationalOther Postretirement Benefits
Years Ended December 31202520242023202520242023202520242023
Service cost$378 $373 $326 $228 $243 $196 $37 $30 $32 
Interest cost569 537 526 303 294 299 61 56 63 
Expected return on plan assets(840)(826)(735)(613)(554)(517)(50)(80)(64)
Amortization of unrecognized prior service (credit) cost
 — (1)(28)(13)(40)(43)(49)
Net loss (gain) amortization58 43 — 11 (3)(45)(51)(42)
Termination benefits2  —  — 
Curtailments9 — (15)— (1)(3)— (1)
Settlements — 28  (1)(5) — — 
Net periodic benefit cost (credit)$176 $132 $155 $(114)$(25)$(29)$(40)$(84)$(61)
In connection with restructuring actions (see Note 5), termination charges were recorded in 2025, 2024 and 2023 on pension and other postretirement benefit plans related to expanded eligibility for certain employees exiting Merck. Also, in connection with these restructuring activities, curtailments and settlements were recorded on certain pension plans. Lump sum payments to U.S. pension plan participants also contributed to the settlements recorded during 2023.
The components of net periodic benefit cost (credit) other than the service cost component are included in Other (income) expense, net (see Note 14), with the exception of certain amounts for termination benefits,
curtailments and settlements, which are recorded in Restructuring costs if the event giving rise to the termination benefits, curtailment or settlement is related to restructuring actions.
Obligations and Funded Status
Summarized information about the changes in plan assets and benefit obligations, the funded status and the amounts recorded at December 31 is as follows:
Pension BenefitsOther
Postretirement
Benefits
U.S.International
202520242025202420252024
Fair value of plan assets January 1$9,717 $9,804 $9,647 $9,562 $1,040 $1,045 
Actual return on plan assets1,435 266 318 637 86 35 
Company contributions267 262 195 198 71 46 
Effects of exchange rate changes — 1,010 (522) — 
Benefits paid(689)(615)(268)(250)(90)(89)
Settlements — (38)(14) — 
Other — 42 36  
Fair value of plan assets December 31$10,730 $9,717 $10,906 $9,647 $1,107 $1,040 
Benefit obligation January 1$10,151 $10,446 $8,274 $9,042 $1,136 $1,104 
Service cost378 373 228 243 37 30 
Interest cost569 537 303 294 61 56 
Actuarial losses (gains) (1)
178 (595)(962)(549)34 32 
Benefits paid(689)(615)(268)(250)(90)(89)
Effects of exchange rate changes — 879 (473)3 (4)
Plan amendments — (5)(56) — 
Curtailments9 — (4)— (2)— 
Termination benefits2   
Settlements — (38)(14) — 
Other — 45 36  
Benefit obligation December 31$10,598 $10,151 $8,452 $8,274 $1,179 $1,136 
Funded status December 31$132 $(434)$2,454 $1,373 $(72)$(96)
Recognized as:
Other Assets$602 $26 $2,770 $1,785 $66 $51 
Accrued and other current liabilities(58)(55)(20)(18)(7)(7)
Other Noncurrent Liabilities(412)(405)(296)(394)(131)(140)
(1)    Actuarial losses (gains) primarily reflect changes in discount rates.
At December 31, 2025 and 2024, the accumulated benefit obligation was $18.7 billion and $18.1 billion, respectively, for all pension plans, of which $10.4 billion and $10.0 billion, respectively, related to U.S. pension plans.
Information related to the funded status of select pension plans at December 31 is as follows:
U.S.International
2025202420252024
Pension plans with a projected benefit obligation in excess of plan assets
Projected benefit obligation
$469 $9,517 $1,405 $1,847 
Fair value of plan assets 9,057 1,089 1,435 
Pension plans with an accumulated benefit obligation in excess of plan assets
Accumulated benefit obligation$449 $442 $1,332 $1,768 
Fair value of plan assets — 1,038 1,385 
Plan Assets
Entities are required to use 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. The Level 3 assets are those whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques with significant unobservable inputs, as well as instruments for which the determination of fair value requires significant judgment or estimation. At December 31, 2025 and 2024, $737 million and $700 million, respectively, or 3% and 4%, respectively, of the Company’s pension investments were categorized as Level 3 assets.
If the inputs used to measure the financial assets 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.
The fair values of the Company’s pension plan assets at December 31 by asset category are as follows:
 Fair Value Measurements UsingFair Value Measurements Using
Level 1Level 2Level 3
NAV (1)
TotalLevel 1Level 2Level 3
NAV (1)
Total
20252024
U.S. Pension Plans
Cash and cash equivalents$200 $ $ $142 $342 $43 $— $— $121 $164 
Investment funds
Developed markets equities196   3,278 3,474 170 — — 2,385 2,555 
Emerging markets equities   905 905 — — — 1,265 1,265 
Real estate   298 298 — — — 174 174 
Equity securities
Developed markets2,109    2,109 2,171 — — — 2,171 
Fixed income securities
Government and agency obligations 2,206   2,206 — 2,101 — — 2,101 
Corporate obligations 1,397   1,397 — 1,293 — — 1,293 
Mortgage and asset-backed securities 18   18 — 21 — — 21 
Other investments (liabilities)
Derivatives(21)   (21)(29)— — — (29)
Other  2  2 — — — 
Plan assets at fair value$2,484 $3,621 $2 $4,623 $10,730 $2,355 $3,415 $$3,945 $9,717 
International Pension Plans
Cash and cash equivalents$90 $5 $ $11 $106 $112 $— $— $11 $123 
Investment funds
Developed markets equities815 4,024  135 4,974 599 3,537 — 96 4,232 
Government and agency obligations323 3,306  157 3,786 262 2,974 — 149 3,385 
Corporate obligations25 10  156 191 23 — 149 180 
Emerging markets equities71   90 161 54 — — 91 145 
Other fixed income obligations27 5  4 36 — 19 
Real estate   17 17 — — — 12 12 
Equity securities
Developed markets289    289 287 — — — 287 
Fixed income securities
Government and agency obligations 413   413 — 368 — — 368 
Corporate obligations 147   147 — 141 — — 141 
Mortgage and asset-backed securities 51   51 — 54 — — 54 
Other investments
Insurance contracts (2)
  735  735 — 698 701 
Plan assets at fair value$1,640 $7,961 $735 $570 $10,906 $1,345 $7,090 $698 $514 $9,647 
(1)    Certain investments that were measured at net asset value (NAV) per share or its equivalent have not been classified in the fair value hierarchy. The NAV amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the fair value of plan assets at December 31, 2025 and 2024.
(2)    The plans’ Level 3 investments in insurance contracts are generally valued using a crediting rate that approximates market returns and invest in underlying securities whose market values are unobservable and determined using pricing models, discounted cash flow methodologies, or similar techniques.
The table below provides a summary of the changes in fair value, including transfers in and/or out, of all financial assets measured at fair value using significant unobservable inputs (Level 3) for the Company’s pension plan assets:
 20252024
Insurance
Contracts
OtherTotalInsurance
Contracts
OtherTotal
U.S. Pension Plans
Balance January 1$ $2 $2 $— $$
Actual return on plan assets:
Relating to assets still held at December 31   — (2)(2)
Relating to assets sold during the year   — 
Purchases and sales, net   — (1)(1)
Balance December 31$ $2 $2 $— $$
International Pension Plans
Balance January 1$698 $ $698 $785 $— $785 
Actual return on plan assets:
Relating to assets still held at December 31117  117 (26)— (26)
Purchases and sales, net(85) (85)(61)— (61)
Transfers into Level 3
5  5 — — — 
Balance December 31$735 $ $735 $698 $— $698 
The fair values of the Company’s other postretirement benefit plan assets at December 31 by asset category are as follows:
 Fair Value Measurements UsingFair Value Measurements Using
Level 1Level 2Level 3
NAV (1)
TotalLevel 1Level 2Level 3
NAV (1)
Total
20252024
Cash and cash equivalents$14 $ $ $4 $18 $— $— $— $$
Investment funds
Developed markets equities3   58 61 — — 46 49 
Emerging markets equities   16 16 — — — 24 24 
Real estate   5 5 — — — 
Equity securities
Developed markets38    38 41 — — — 41 
Fixed income securities
Corporate obligations 645   645 — 598 — — 598 
Government and agency obligations 261   261 — 266 — — 266 
Mortgage and asset-backed securities 63   63 — 54 — — 54 
Plan assets at fair value$55 $969 $ $83 $1,107 $44 $918 $— $78 $1,040 
(1)    Certain investments that were measured at net asset value (NAV) per share or its equivalent have not been classified in the fair value hierarchy. The NAV amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the fair value of plan assets at December 31, 2025 and 2024.
The Company has established investment guidelines for its U.S. pension and other postretirement plans to create an asset allocation that is expected to deliver a rate of return sufficient to meet the long-term obligation of each plan, given an acceptable level of risk. The target investment portfolio of the Company’s U.S. pension and other postretirement benefit plans is allocated 25% to 40% in U.S. equities, 15% to 30% in international equities, 40% to 50% in fixed-income investments, and up to 8% in cash and other investments. The portfolio’s equity weighting is consistent with the long-term nature of the plans’ benefit obligations. The expected annual standard deviation of returns of the target portfolio, which approximates 11%, reflects both the equity allocation and the diversification benefits among the asset classes in which the portfolio invests. For international pension plans, the targeted investment portfolio varies based on the duration of pension liabilities and local government rules and regulations. Concentration risk is mitigated by utilizing diversified investment strategies within portfolios.
Expected Contributions
Contributions during 2026 are expected to be approximately $270 million for U.S. pension plans, approximately $190 million for international pension plans and approximately $70 million for other postretirement benefit plans.
Expected Benefit Payments
Expected benefit payments are as follows:
U.S. Pension BenefitsInternational Pension
Benefits
Other
Postretirement
Benefits
2026$834 $334 $88 
2027832 323 90 
2028833 336 94 
2029847 354 98 
2030866 362 102 
2031 — 20354,531 2,108 554 
Expected benefit payments are based on the same assumptions used to measure the benefit obligations and include estimated future employee service.
Amounts Recognized in Other Comprehensive Income (Loss)
Net gain/loss amounts reflect differences between expected and actual returns on plan assets as well as the effects of changes in actuarial assumptions. Net gain/loss amounts in excess of certain thresholds are amortized into net periodic benefit cost over the average remaining service life of employees. The following amounts were reflected as components of OCI:
 Pension PlansOther Postretirement
Benefit Plans
U.S.International
Years Ended December 31202520242023202520242023202520242023
Net gain (loss) arising during the period$408 $35 $(69)$686 $634 $(438)$2 $(78)$110 
Prior service credit (cost) arising during the period — — 5 56 (16) — — 
 $408 $35 $(69)$691 $690 $(454)$2 $(78)$110 
Net loss (gain) amortization included in benefit cost$58 $43 $— $11 $$(3)$(45)$(51)$(42)
Prior service (credit) cost amortization included in benefit cost — (1)(28)(13)(40)(43)(49)
Settlements and curtailments9 — 36 (15)(1)(6)(3)— (1)
 $67 $43 $35 $(32)$(9)$(7)$(88)$(94)$(92)
Actuarial Assumptions
The Company reassesses its benefit plan assumptions on a regular basis. The weighted average assumptions used in determining U.S. pension and other postretirement benefit plan and international pension plan information are as follows:
 U.S. Pension and Other
Postretirement Benefit Plans
International Pension Plans
December 31202520242023202520242023
Net periodic benefit cost      
Discount rate5.70 %5.30 %5.50 %3.70 %3.40 %3.90 %
Expected rate of return on plan assets7.70 %7.75 %7.00 %5.40 %5.20 %5.00 %
Salary growth rate4.80 %4.60 %4.60 %3.10 %3.20 %3.20 %
Interest crediting rate5.40 %5.30 %5.30 %3.50 %3.40 %3.30 %
Benefit obligation      
Discount rate5.60 %5.70 %5.30 %4.20 %3.70 %3.40 %
Salary growth rate4.80 %4.80 %4.60 %3.10 %3.10 %3.20 %
Interest crediting rate5.40 %5.40 %5.30 %3.70 %3.50 %3.40 %
For both the pension and other postretirement benefit plans, the discount rate is evaluated on measurement dates and modified to reflect the prevailing market rate of a portfolio of high-quality fixed-income debt instruments that would provide the future cash flows needed to pay the benefits included in the benefit obligation as they come due. The expected rate of return for both the pension and other postretirement benefit plans represents the average rate of return to be earned on plan assets over the period the benefits included in the benefit obligation are to be paid and is determined on a plan basis. The expected rate of return for each plan is developed considering long-term historical returns data, current market conditions, and actual returns on the plan assets. Using this reference information, the long-term return expectations for each asset category and a weighted-average expected return for each plan’s target portfolio is developed according to the allocation among those investment categories. The expected portfolio performance reflects the contribution of active management as appropriate. For 2026, the expected rate of return for the Company’s U.S. pension and other postretirement benefit plans will be 7.70%, which is the same as 2025.
The health care cost trend rate assumptions for other postretirement benefit plans are as follows:
December 3120252024
Health care cost trend rate assumed for next year8.50 %7.90 %
Rate to which the cost trend rate is assumed to decline4.50 %4.50 %
Year that the trend rate reaches the ultimate trend rate20412040

Savings Plans
The Company also maintains defined contribution savings plans in the U.S. The Company matches a percentage of each employee’s contributions consistent with the provisions of the plan for which the employee is eligible. Total employer contributions to these plans in 2025, 2024 and 2023 were $223 million, $215 million and $199 million, respectively.
v3.25.4
Other (Income) Expense, Net
12 Months Ended
Dec. 31, 2025
Other Income and Expenses [Abstract]  
Other (Income) Expense, Net Other (Income) Expense, Net
Other (income) expense, net, consisted of:
Years Ended December 31202520242023
Interest income$(343)$(415)$(365)
Interest expense1,357 1,271 1,146 
Exchange losses323 227 370 
Income from investments in equity securities, net (1)
(368)(14)(340)
Net periodic defined benefit plan (credit) cost other than service cost(615)(633)(498)
Other, net(203)(460)153 
 $151 $(24)$466 
(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 2024 includes $170 million of income related to the expansion of a collaboration agreement with Daiichi Sankyo (see Note 4). Other, net, in 2023 includes a $572.5 million charge related to settlements with certain plaintiffs in the Zetia antitrust litigation (see Note 10).
Interest paid was $1.3 billion in 2025, $1.3 billion in 2024 and $1.1 billion in 2023.
v3.25.4
Taxes on Income
12 Months Ended
Dec. 31, 2025
Income Tax Disclosure [Abstract]  
Taxes on Income Taxes on Income
As discussed in Note 2, the Company prospectively adopted a new accounting standard effective for 2025 reporting that requires disaggregation of information in the effective income tax rate reconciliation and income taxes paid disclosures.
A reconciliation between the effective income tax rate and the U.S. statutory rate (in accordance with the new guidance) for 2025 is as follows:
2025
AmountTax Rate
U.S. statutory rate applied to income before taxes$4,424 21.0 %
Differential arising from:
State and local income taxes, net of federal benefit (1)
12 0.1 
Foreign tax effects:
Switzerland
Tax rate differential between Switzerland and the U.S.(1,428)(6.8)
Withholding taxes284 1.3 
Other (2)
59 0.3 
Netherlands
Tax rate differential between Netherlands and the U.S.409 1.9 
Innovation box(1,042)(4.9)
Other(66)(0.3)
Other foreign jurisdictions308 1.5 
Effect of cross-border tax laws:
Net controlled foreign corporation tested income3,759 17.8 
Foreign-derived deduction-eligible income(31)(0.1)
Subpart F227 1.1 
Tax credits:
Foreign tax credits(4,190)(19.9)
Research and development tax credits(260)(1.2)
Valuation allowances76 0.4 
Nontaxable or nondeductible items(78)(0.4)
Changes in unrecognized tax benefits341 1.5 
$2,804 13.3 %
(1)    State and local tax expense was not material in 2025.
(2)    Includes the impact of Cantonal tax holiday and OECD Pillar 2.
A reconciliation between the effective income tax rate and the U.S. statutory rate (as previously reported in accordance with guidance prior to the adoption of the new accounting standard) for 2024 and 2023 is as follows:
 20242023
AmountTax RateAmountTax Rate
U.S. statutory rate applied to income before taxes
$4,186 21.0 %$397 21.0 %
Differential arising from:
Foreign earnings(1,301)(6.5)(941)(49.8)
Tax settlements and statute lapses
(557)(2.8)— — 
R&D tax credit(202)(1.0)(214)(11.3)
Inventory donations
(71)(0.4)(65)(3.5)
State taxes(39)(0.2)(117)(6.2)
Charges for certain research and development asset acquisitions
554 2.8 253 13.4 
Valuation allowances54 0.3 70 3.7 
Restructuring52 0.3 41 2.2 
GILTI and the foreign-derived intangible income deduction29 0.1 (80)(4.3)
Acquisition-related costs, including amortization
18 0.1 42 2.2 
Acquisition of Prometheus
— — 2,139 113.3 
Other80 0.4 (13)(0.7)
 $2,803 14.1 %$1,512 80.0 %
Where applicable, the impact of changes in uncertain tax positions is reflected in the reconciling items above.
In 2025, the Company made the final installment payment due related to the transition tax liability under the Tax Cuts and Jobs Act (TCJA) of 2017 of $1.2 billion. As of December 31, 2025, the Company has $702 million of foreign tax credits included in Other Assets that Merck expects to be applied upon the completion of the Internal Revenue Service’s (IRS) examination of the Company’s tax returns for the 2017 and 2018 federal tax years. As a result of the transition tax under the TCJA, the Company is no longer indefinitely reinvested with respect to its undistributed earnings from foreign subsidiaries and has provided a deferred tax liability for foreign withholding taxes that would apply. The Company remains indefinitely reinvested with respect to its financial statement basis in excess of tax basis of its foreign subsidiaries. A determination of the net deferred tax liability with respect to this basis difference is not practicable.
The foreign earnings tax rate differentials in the tax rate reconciliations above primarily reflect the impacts of operations in jurisdictions with different effective tax rates than the U.S., particularly Switzerland, the Netherlands and Ireland, as well as Singapore and Puerto Rico which operate under tax incentive grants (which begin to expire in 2025), thereby yielding a favorable impact on the effective tax rate compared with the U.S. statutory rate of 21%. The Company has an additional Cantonal tax holiday in Switzerland that provides for a tax rate reduction and is effective through 2032. The Company’s income that is subject to tax incentive grants and the Cantonal tax holiday in Switzerland is subject to the global minimum tax provision of the Organization for Economic Cooperation and Development (OECD) Pillar 2, effective in 2024.
Income before taxes consisted of:
Years Ended December 31202520242023
Domestic$(4,948)$(1,849)$(15,622)
Foreign26,015 21,785 17,511 
 $21,067 $19,936 $1,889 
Taxes on income consisted of:
Years Ended December 31202520242023
Current provision
Federal$499 $944 $928 
Foreign4,072 3,123 2,435 
State(96)(15)48 
 4,475 4,052 3,411 
Deferred provision
Federal(1,585)(1,475)(1,559)
Foreign(83)212 (233)
State(3)14 (107)
 (1,671)(1,249)(1,899)
 $2,804 $2,803 $1,512 
Deferred income taxes at December 31 consisted of:
 20252024
AssetsLiabilitiesAssetsLiabilities
Product intangibles and licenses$140 $3,272 $71 $978 
R&D capitalization4,134  3,062 — 
Inventory related72 451 84 413 
Accelerated depreciation 594 — 645 
Undistributed foreign earnings
119 338 275 371 
Equity investments 155 — 90 
Pensions and other postretirement benefits117 623 224 400 
Compensation related382  400 — 
Unrecognized tax benefits160  152 — 
Net operating losses and other tax credit carryforwards1,197  910 — 
Other1,236 134 802 159 
Subtotal7,557 5,567 5,980 3,056 
Valuation allowance(824) (710) 
Total deferred taxes$6,733 $5,567 $5,270 $3,056 
Net deferred income taxes$1,166 $2,214 
Recognized as:
Other Assets$2,605 $3,601 
Deferred Income Taxes $1,439  $1,387 
The Company has net operating loss (NOL) carryforwards in several jurisdictions. As of December 31, 2025, $384 million of deferred tax assets on NOL carryforwards relate to foreign jurisdictions. Valuation allowances of $248 million have been established on these foreign NOL carryforwards and other foreign deferred tax assets. In addition, the Company has $813 million of deferred tax assets relating to various U.S. tax credit carryforwards and NOL carryforwards. Valuation allowances of $576 million have been established on these U.S. tax credit carryforwards and NOL carryforwards.
Income taxes paid in 2025 (presented in accordance with the new guidance) consisted of:
Year Ended December 31
2025
Domestic - federal (1)
$1,559 
Domestic - state and local
24 
Switzerland
2,115 
Netherlands
1,576 
Other foreign
812 
$6,086 
(1)    Includes TCJA transition tax payments.
Income taxes paid in 2024 and 2023 consisted of:
Years Ended December 3120242023
Domestic (1)
$974 $2,258 
Foreign2,954 2,080 
 $3,928 $4,338 
(1)    Includes TCJA transition tax payments.
Prepaid income taxes included in Other current assets were $5.7 billion and $3.9 billion at December 31, 2025 and 2024, respectively. Tax benefits relating to stock option exercises were $7 million in 2025, $26 million in 2024 and $12 million in 2023.
A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
202520242023
Balance January 1$2,261 $2,384 $1,835 
Additions related to current year positions396 421 553 
Additions related to prior year positions59 35 91 
Reductions for tax positions of prior years
(94)(33)(20)
Settlements
(28)(18)(23)
Lapse of statute of limitations (1)
(64)(528)(52)
Balance December 31$2,530 $2,261 $2,384 
(1)    Amount in 2024 reflects a reduction of $451 million resulting from the expiration of the statute of limitations related to the 2019 and 2020 federal tax return years.
If the Company were to recognize the unrecognized tax benefits of $2.5 billion at December 31, 2025, the income tax provision would reflect a favorable net impact of $2.5 billion.
Interest and penalties associated with uncertain tax positions amounted to $106 million in 2025, $51 million in 2024 and $131 million in 2023. These amounts reflect the beneficial impacts of various tax settlements. Liabilities for accrued interest and penalties were $546 million and $437 million as of December 31, 2025 and 2024, respectively.
The 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 may take a number of years to reach resolution of this matter. If the Company is ultimately unsuccessful in defending its position, the impact could be material to its financial statements. In 2024, the Company recorded a benefit of $519 million due to a reduction in reserves for unrecognized income tax benefits resulting from the expiration in 2024 of the statute of limitations for assessments related to the 2019 and 2020 federal tax return years. The IRS is also currently conducting examinations of the Company’s tax returns for the years 2021 and 2022. In addition, various state and foreign tax examinations are in progress and for these jurisdictions, the Company’s income tax returns are open for examination for the period 2011 through 2025.
v3.25.4
Earnings per Share
12 Months Ended
Dec. 31, 2025
Earnings Per Share [Abstract]  
Earnings per Share Earnings per Share
The calculations of earnings per share (shares in millions) are as follows:
Years Ended December 31202520242023
Net Income Attributable to Merck & Co., Inc.$18,254 $17,117 $365 
Average common shares outstanding2,502 2,532 2,537 
Common shares issuable (1)
5 10 
Average common shares outstanding assuming dilution2,507 2,541 2,547 
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders$7.30 $6.76 $0.14 
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders$7.28 $6.74 $0.14 
(1)     Issuable primarily under share-based compensation plans.
In 2025, 2024 and 2023, 11 million, 6 million and 5 million, respectively, of common shares issuable under share-based compensation plans were excluded from the computation of earnings per common share assuming dilution because the effect would have been antidilutive.
v3.25.4
Other Comprehensive Income (Loss)
12 Months Ended
Dec. 31, 2025
Equity [Abstract]  
Other Comprehensive Income (Loss) Other Comprehensive Income (Loss)
Changes in each component of other comprehensive income (loss) are as follows:
DerivativesEmployee
Benefit
Plans
 Foreign Currency
Translation
Adjustment
Accumulated Other
Comprehensive Loss
Balance at January 1, 2023, net of taxes
$73 $(2,408)$(2,433)$(4,768)
Other comprehensive income (loss) before reclassification adjustments, pretax114 (413)17 (282)
Tax(24)86 63 125 
Other comprehensive income (loss) before reclassification adjustments, net of taxes90 (327)80 (157)
Reclassification adjustments, pretax(237)
(1)
(64)
(2)
(292)
Tax50 — 56 
Reclassification adjustments, net of taxes(187)(58)(236)
Other comprehensive income (loss), net of taxes(97)(385)89 (393)
Balance at December 31, 2023, net of taxes(24)(2,793)(2,344)(5,161)
Other comprehensive income (loss) before reclassification adjustments, pretax508 647 (559)596 
Tax(109)(138)23 (224)
Other comprehensive income (loss) before reclassification adjustments, net of taxes399 509 (536)372 
Reclassification adjustments, pretax(168)
(1)
(60)
(2)
20 (208)
Tax35 17 — 52 
Reclassification adjustments, net of taxes(133)(43)20 (156)
Other comprehensive income (loss), net of taxes266 466 (516)216 
Balance at December 31, 2024, net of taxes242 (2,327)
(3)
(2,860)(4,945)
Other comprehensive income (loss) before reclassification adjustments, pretax(577)1,101 254 778 
Tax124 (232)(77)(185)
Other comprehensive income (loss) before reclassification adjustments, net of taxes(453)869 177 593 
Reclassification adjustments, pretax134 
(1)
(53)
(2)
 81 
Tax(28)12  (16)
Reclassification adjustments, net of taxes106 (41) 65 
Other comprehensive income (loss), net of taxes(347)828 177 658 
Balance at December 31, 2025, net of taxes$(105)$(1,499)
(3)
$(2,683)$(4,287)
(1)    Primarily relates to foreign currency cash flow hedges that were reclassified from AOCL to Sales (see Note 6).
(2)    Includes net amortization of prior service cost, actuarial gains and losses, settlements and curtailments included in net periodic benefit cost (see Note 13).
(3)    Includes pension plan net loss of $2.0 billion and $3.0 billion at December 31, 2025 and 2024, respectively, and other postretirement benefit plan net gain of $365 million and $400 million at December 31, 2025 and 2024, respectively, as well as pension plan prior service credit of $146 million and $174 million at December 31, 2025 and 2024, respectively, and other postretirement benefit plan prior service credit of $29 million and $61 million at December 31, 2025 and 2024, respectively.
v3.25.4
Segment Reporting
12 Months Ended
Dec. 31, 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:
Years Ended December 31202520242023
U.S.Int’lTotalU.S.Int’lTotalU.S.Int’lTotal
Pharmaceutical:
Oncology
Keytruda$18,829 $12,812 $31,641 $17,872 $11,610 $29,482 $15,114 $9,897 $25,011 
Keytruda Qlex
38 2 40 — — — — — — 
Alliance revenue - Lynparza (1)
683 767 1,450 626 685 1,311 607 592 1,199 
Alliance revenue - Lenvima (1)
737 316 1,053 705 305 1,010 657 303 960 
Welireg603 113 716 466 43 509 209 10 218 
Alliance revenue - Reblozyl (2)
432 93 525 303 68 371 168 43 212 
Vaccines
Gardasil/Gardasil 9
2,641 2,592 5,233 2,425 6,158 8,583 2,083 6,803 8,886 
ProQuad/M-M-R II/Varivax1,885 566 2,451 1,919 566 2,485 1,837 531 2,368 
Vaxneuvance459 366 825 461 347 808 561 103 665 
Capvaxive
730 29 759 96 97 — — — 
RotaTeq426 246 673 472 239 711 493 276 769 
Pneumovax 23
21 146 166 56 207 263 127 285 412 
Hospital Acute Care
Bridion1,631 209 1,841 1,401 363 1,764 1,156 686 1,842 
Prevymis475 503 978 371 414 785 264 341 605 
Zerbaxa186 126 312 146 106 252 119 100 218 
Dificid202 45 247 303 37 340 274 28 302 
Cardiometabolic and Respiratory
Winrevair
1,358 85 1,443 408 11 419 — — — 
Alliance revenue - Adempas/Verquvo (3)
421 49 470 388 27 415 350 16 367 
Adempas 312 312 — 287 287 — 255 255 
Ohtuvayre
178  178 — — — — — — 
Virology
Lagevrio101 278 380 176 787 964 10 1,418 1,428 
Isentress/Isentress HD181 144 325 185 209 394 215 268 483 
Delstrigo
56 250 306 56 193 249 49 152 201 
Pifeltro
111 59 171 113 50 163 101 41 142 
Neuroscience
Belsomra82 104 186 72 150 222 81 150 231 
Immunology
Simponi   — 543 543 — 710 710 
Remicade   — 114 114 — 187 187 
Diabetes
Januvia999 605 1,604 469 865 1,334 1,151 1,039 2,189 
Janumet268 672 940 161 774 935 223 954 1,177 
Other pharmaceutical (4)
676 2,244 2,917 640 1,951 2,590 690 1,856 2,546 
Total Pharmaceutical segment sales34,409 23,733 58,142 30,290 27,110 57,400 26,539 27,044 53,583 
Animal Health:
Livestock807 3,089 3,896 732 2,729 3,462 700 2,637 3,337 
Companion Animal1,146 1,312 2,458 1,129 1,287 2,415 1,104 1,184 2,288 
Total Animal Health segment sales1,953 4,401 6,354 1,861 4,016 5,877 1,804 3,821 5,625 
Total segment sales36,362 28,134 64,496 32,151 31,126 63,277 28,343 30,865 59,208 
Other (5)
148 367 515 126 765 891 137 770 907 
 $36,510 $28,501 $65,011 $32,277 $31,891 $64,168 $28,480 $31,635 $60,115 
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 4).
(2)    Alliance revenue for Reblozyl represents royalties (see Note 4).
(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 4).
(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 $436 million, $170 million, and $97 million in 2025, 2024 and 2023, respectively (see Note 4).
(5)    Other is primarily comprised of miscellaneous corporate revenue, including revenue hedging activities which (decreased) increased sales by $(127) million, $195 million and $244 million in 2025, 2024 and 2023, respectively, as well as revenue from third-party manufacturing arrangements (including sales to Organon & Co.). Other for 2025, 2024 and 2023 also includes $138 million, $106 million and $118 million, respectively, related to upfront and milestone payments received by Merck for out-licensing arrangements.
Consolidated sales by geographic area where derived are as follows:
Years Ended December 31202520242023
United States$36,510 $32,277 $28,480 
Europe, Middle East and Africa14,580 14,041 13,254 
Latin America3,410 3,459 3,086 
Asia Pacific (other than Japan and China)
2,983 3,058 3,225 
Japan2,711 3,280 3,164 
China1,939 5,494 6,802 
Other2,878 2,559 2,104 
 $65,011 $64,168 $60,115 
A reconciliation of segment profits to Income Before Taxes is as follows:
Years Ended December 31202520242023
Pharma-ceutical
Animal Health
Total
Pharma-ceutical
Animal Health
Total
Pharma-ceutical
Animal Health
Total
Segment sales
$58,142 $6,354 $64,496 $57,400 $5,877 $63,277 $53,583 $5,625 $59,208 
Less segment costs: (1)
Cost of sales
6,679 2,649 6,828 2,469 8,849 2,498 
Selling, general and administrative
5,874 1,125 6,128 1,084 5,903 1,038 
Research and development (2)
 448 — 385 — 353 
Other segment items (3)
(165)1 (89)(49)(1)
Total segment profits45,754 2,131 47,885 44,533 1,938 46,471 38,880 1,737 40,617 
Other profits251 492 474 
Unallocated:
Interest income343 415 365 
Interest expense(1,357)(1,271)(1,146)
Amortization(2,793)(2,395)(2,044)
Depreciation(2,758)(1,843)(1,625)
Research and development(14,987)(17,350)(30,008)
Restructuring costs(889)(309)(599)
Charge for Zetia antitrust litigation settlements — (573)
Other unallocated, net(4,628)(4,274)(3,572)
$21,067 $19,936 $1,889 
(1)    The significant expense categories and amounts align with the segment level information that is regularly provided to the chief operating decision maker.
(2)    Human health-related research and development expenses incurred by Merck Research Laboratories are not allocated to segment profits as noted below.
(3)    Includes equity (income) loss from affiliates and other miscellaneous non-operating expenses.

Pharmaceutical segment profits consist of segment sales less standard costs, as well as selling, general and administrative expenses directly incurred by the segment. Animal Health segment profits consist of segment sales, less all cost of sales, as well as selling, general and administrative expenses and research and development costs directly incurred by the segment. The chief operating decision maker (Merck’s Chief Executive Officer) uses segment profit for the purpose of evaluating performance, allocating resources, informing incentive compensation targets and setting strategic Company goals during the planning and forecasting process. On a quarterly basis, the CEO considers forecast-to-actual variances in segment profit when assessing performance of the segments and making decisions about allocating resources to the segments. For internal management reporting presented to the chief operating decision maker, Merck does not allocate the remaining cost of sales not included in segment profits as described above, research and development expenses incurred by Merck Research Laboratories, the Company’s research and development division that focuses on human health-related activities, or general and administrative expenses not directly incurred by the segments, nor the cost of financing these activities. Separate divisions maintain responsibility for monitoring and managing these costs, including depreciation related to fixed assets utilized by these divisions and, therefore, they are not included in segment profits. In addition, costs related to restructuring activities, as well as the amortization of intangible assets and the recognition of fair value step-up of inventories are not allocated to segments.
Other profits are primarily comprised of miscellaneous corporate profits, as well as operating profits (losses) related to third-party manufacturing arrangements.
Other unallocated, net, includes expenses from corporate and manufacturing cost centers, intangible asset impairment charges, gains or losses on sales of businesses, expense or income related to changes in the estimated fair value measurement of liabilities for contingent consideration, and other miscellaneous income or expense items.
Equity income from affiliates and depreciation included in segment profits is as follows:
PharmaceuticalAnimal HealthTotal
Year Ended December 31, 2025
Equity income from affiliates$190 $ $190 
Depreciation5 282 287 
Year Ended December 31, 2024
Equity income from affiliates$144 $— $144 
Depreciation256 261 
Year Ended December 31, 2023
Equity income from affiliates
$111 $— $111 
Depreciation198 203 
Property, plant and equipment, net, by geographic area where located is as follows:
December 31202520242023
United States$15,021 $14,724 $13,915 
Europe, Middle East and Africa8,856 7,548 7,562 
Asia Pacific (other than China and Japan)898 982 1,022 
China218 202 193 
Japan144 143 133 
Latin America128 133 222 
Other51 47 
 $25,316 $23,779 $23,051 
The Company does not disaggregate assets on a products and services basis for internal management reporting and, therefore, such information is not presented.
v3.25.4
Insider Trading Arrangements
3 Months Ended
Dec. 31, 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
v3.25.4
Insider Trading Policies and Procedures
12 Months Ended
Dec. 31, 2025
Insider Trading Policies and Procedures [Line Items]  
Insider Trading Policies and Procedures Adopted true
v3.25.4
Cybersecurity Risk Management and Strategy Disclosure
12 Months Ended
Dec. 31, 2025
Cybersecurity Risk Management, Strategy, and Governance [Line Items]  
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]
The Company’s cybersecurity measures are primarily focused on ensuring the security and protection of its IT systems and data. The Company’s information security program is managed by a dedicated Chief Information Security Officer (CISO), whose group is responsible for leading enterprise-wide cybersecurity risk management, strategy, policy, standards, architecture, and processes. The Company’s interim CISO has over 22 years of experience in cybersecurity and national security, including distinguished service in the U.S. Army and the National Security Agency. He holds a Master’s degree in Cyber Intelligence Studies and a Bachelor’s degree in Mathematical Physics, and maintains the Certified Information Systems Security Professional (CISSP) credential. Oversight of the information security program remains fully integrated into the Company’s overall enterprise risk management framework.
The CISO provides periodic reports to the Audit Committee (Audit Committee) of the Board of Directors (Board), the full Board, as well as to the Company’s Chief Executive Officer and other members of senior management, as appropriate. These reports include updates on the Company’s cybersecurity risks and threats, the status of projects intended to strengthen its information security systems, assessments of the information security program (including remediation, mitigation, and management of identified vulnerabilities), and the emerging threat landscape. The information security program is regularly evaluated by internal and external consultants and auditors with the results of those reviews reported to senior management and the Audit Committee, which is comprised entirely of independent directors and has oversight responsibility for these risks.
The Company’s information security group monitors the Company’s information systems to prevent, detect, mitigate, and remediate cybersecurity incidents. The Company uses tools and techniques to continually assess and monitor, manage and mitigate cybersecurity threats to its IT systems in a manner consistent with industry practice. The Company engages with key vendors, industry participants, and intelligence and law enforcement communities as part of its continuing efforts to obtain current threat intelligence, collaborate on security enhancements, and evaluate and improve the effectiveness of its information security program. As part of this program, the Company conducts periodic tabletop and red-teaming exercises to assess its cybersecurity incident response processes and defenses. The Company also maintains vendor management diligence and oversight processes to identify and monitor potential risks from cybersecurity threats attendant to its use of third-party service providers. Additionally, the Company monitors cybersecurity threat intelligence received from key third-party service providers associated with the Company.
Cybersecurity Risk Management Processes Integrated [Flag] true
Cybersecurity Risk Management Processes Integrated [Text Block]
The Company’s cybersecurity measures are primarily focused on ensuring the security and protection of its IT systems and data. The Company’s information security program is managed by a dedicated Chief Information Security Officer (CISO), whose group is responsible for leading enterprise-wide cybersecurity risk management, strategy, policy, standards, architecture, and processes. The Company’s interim CISO has over 22 years of experience in cybersecurity and national security, including distinguished service in the U.S. Army and the National Security Agency. He holds a Master’s degree in Cyber Intelligence Studies and a Bachelor’s degree in Mathematical Physics, and maintains the Certified Information Systems Security Professional (CISSP) credential. Oversight of the information security program remains fully integrated into the Company’s overall enterprise risk management framework.
Cybersecurity Risk Management Third Party Engaged [Flag] true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag] true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag] false
Cybersecurity Risk Board of Directors Oversight [Text Block] The CISO provides periodic reports to the Audit Committee (Audit Committee) of the Board of Directors (Board), the full Board, as well as to the Company’s Chief Executive Officer and other members of senior management, as appropriate. These reports include updates on the Company’s cybersecurity risks and threats, the status of projects intended to strengthen its information security systems, assessments of the information security program (including remediation, mitigation, and management of identified vulnerabilities), and the emerging threat landscape. The information security program is regularly evaluated by internal and external consultants and auditors with the results of those reviews reported to senior management and the Audit Committee, which is comprised entirely of independent directors and has oversight responsibility for these risks.
In the event of a cybersecurity incident, the Company has a process in place whereby members of the information security group will alert the CISO and the CISO will alert the appropriate levels of management, including an incident assessment team, as well as the legal and finance departments so that the materiality of any such event can be assessed in furtherance of fulfilling any reporting requirements. If warranted, senior management will notify the Audit Committee or the full Board, as appropriate.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block] The information security program is regularly evaluated by internal and external consultants and auditors with the results of those reviews reported to senior management and the Audit Committee, which is comprised entirely of independent directors and has oversight responsibility for these risks.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block] The CISO provides periodic reports to the Audit Committee (Audit Committee) of the Board of Directors (Board), the full Board, as well as to the Company’s Chief Executive Officer and other members of senior management, as appropriate. These reports include updates on the Company’s cybersecurity risks and threats, the status of projects intended to strengthen its information security systems, assessments of the information security program (including remediation, mitigation, and management of identified vulnerabilities), and the emerging threat landscape. The information security program is regularly evaluated by internal and external consultants and auditors with the results of those reviews reported to senior management and the Audit Committee, which is comprised entirely of independent directors and has oversight responsibility for these risks.
In the event of a cybersecurity incident, the Company has a process in place whereby members of the information security group will alert the CISO and the CISO will alert the appropriate levels of management, including an incident assessment team, as well as the legal and finance departments so that the materiality of any such event can be assessed in furtherance of fulfilling any reporting requirements. If warranted, senior management will notify the Audit Committee or the full Board, as appropriate.
Cybersecurity Risk Role of Management [Text Block]
The Company’s cybersecurity measures are primarily focused on ensuring the security and protection of its IT systems and data. The Company’s information security program is managed by a dedicated Chief Information Security Officer (CISO), whose group is responsible for leading enterprise-wide cybersecurity risk management, strategy, policy, standards, architecture, and processes. The Company’s interim CISO has over 22 years of experience in cybersecurity and national security, including distinguished service in the U.S. Army and the National Security Agency. He holds a Master’s degree in Cyber Intelligence Studies and a Bachelor’s degree in Mathematical Physics, and maintains the Certified Information Systems Security Professional (CISSP) credential. Oversight of the information security program remains fully integrated into the Company’s overall enterprise risk management framework.
In the event of a cybersecurity incident, the Company has a process in place whereby members of the information security group will alert the CISO and the CISO will alert the appropriate levels of management, including an incident assessment team, as well as the legal and finance departments so that the materiality of any such event can be assessed in furtherance of fulfilling any reporting requirements. If warranted, senior management will notify the Audit Committee or the full Board, as appropriate.
Cybersecurity Risk Management Positions or Committees Responsible [Flag] true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block] The Company’s information security program is managed by a dedicated Chief Information Security Officer (CISO), whose group is responsible for leading enterprise-wide cybersecurity risk management, strategy, policy, standards, architecture, and processes.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block] The Company’s interim CISO has over 22 years of experience in cybersecurity and national security, including distinguished service in the U.S. Army and the National Security Agency. He holds a Master’s degree in Cyber Intelligence Studies and a Bachelor’s degree in Mathematical Physics, and maintains the Certified Information Systems Security Professional (CISSP) credential. Oversight of the information security program remains fully integrated into the Company’s overall enterprise risk management framework
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]
The CISO provides periodic reports to the Audit Committee (Audit Committee) of the Board of Directors (Board), the full Board, as well as to the Company’s Chief Executive Officer and other members of senior management, as appropriate. These reports include updates on the Company’s cybersecurity risks and threats, the status of projects intended to strengthen its information security systems, assessments of the information security program (including remediation, mitigation, and management of identified vulnerabilities), and the emerging threat landscape. The information security program is regularly evaluated by internal and external consultants and auditors with the results of those reviews reported to senior management and the Audit Committee, which is comprised entirely of independent directors and has oversight responsibility for these risks.
In the event of a cybersecurity incident, the Company has a process in place whereby members of the information security group will alert the CISO and the CISO will alert the appropriate levels of management, including an incident assessment team, as well as the legal and finance departments so that the materiality of any such event can be assessed in furtherance of fulfilling any reporting requirements. If warranted, senior management will notify the Audit Committee or the full Board, as appropriate.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag] true
v3.25.4
Summary of Accounting Policies (Policies)
12 Months Ended
Dec. 31, 2025
Accounting Policies [Abstract]  
Principles of Consolidation
Principles of Consolidation — The consolidated financial statements include the accounts of the Company and all of its subsidiaries in which a controlling interest is maintained. Intercompany balances and transactions are eliminated. Controlling interest is determined by majority ownership interest and the absence of substantive third-party participating rights or, in the case of variable interest entities, by majority exposure to expected losses, residual returns or both. For those consolidated subsidiaries where Merck ownership is less than 100%, the outside shareholders’ interests are shown as Noncontrolling Interests in equity. Investments in affiliates over which the Company has significant influence but not a controlling interest, such as interests in entities owned equally by the Company and a third party that are under shared control, are carried on the equity method basis.
Acquisitions
Acquisitions — In a business combination, the acquisition method of accounting requires that the assets acquired and liabilities assumed be recorded as of the date of the acquisition at their respective fair values with limited exceptions. Assets acquired and liabilities assumed in a business combination that arise from contingencies are generally recognized at fair value. If fair value cannot be determined, the asset or liability is recognized if probable and reasonably estimable; if these criteria are not met, no asset or liability is recognized. 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. Accordingly, the Company may be required to value assets at fair value measures that do not reflect the Company’s intended use of those assets. Any excess of the purchase price (consideration transferred) over the estimated fair values of net assets acquired is recorded as goodwill. Transaction costs and costs to restructure the acquired company are expensed as incurred. The operating results of the acquired business are reflected in the Company’s consolidated financial statements after the date of the acquisition.
If the Company determines the assets acquired do not meet the definition of a business under the acquisition method of accounting, the transaction will be accounted for as an asset acquisition rather than a business combination and, therefore, no goodwill will be recorded. In an asset acquisition, acquired in-process research and development (IPR&D) with no alternative future use is charged to expense, currently marketed products are capitalized as intangible assets, and contingent consideration is not recognized at the acquisition date.
Foreign Currency Translation
Foreign Currency Translation — The net assets of international subsidiaries where the local currencies have been determined to be the functional currencies are translated into U.S. dollars using current exchange rates and results of operations are translated at average exchange rates. The U.S. dollar effects that arise from translating the net assets of these subsidiaries at changing rates are recorded in Other Comprehensive Income (OCI) and remain in Accumulated other comprehensive loss (AOCL) until either the sale or complete or substantially complete liquidation of the subsidiary. For those subsidiaries that operate in highly inflationary economies and for those subsidiaries where the U.S. dollar has been determined to be the functional currency, non-monetary foreign currency
assets and liabilities are translated using historical rates, while monetary assets and liabilities are translated at current rates, with the U.S. dollar effects of rate changes included in Other (income) expense, net.
Cash Equivalents
Cash Equivalents — Cash equivalents consist of certain highly liquid investments with original maturities of less than three months.
Inventories
Inventories — Inventories are valued at the lower of cost or net realizable value. The cost of a substantial majority of U.S. human health inventories is determined using the last-in, first-out (LIFO) method for both financial reporting and tax purposes. The cost of all other inventories is determined using the first-in, first-out (FIFO) method. Inventories consist of currently marketed products, as well as certain inventories produced in preparation for product launches that are considered by the Company to be probable of obtaining regulatory approval. In evaluating the recoverability of inventories produced in preparation for product launches, the Company considers the likelihood that revenue will be obtained from the future sale of the related inventory together with the status of the product during the research and regulatory approval process.
Investments
Investments — Investments in marketable debt securities classified as available-for-sale are reported at fair value. Fair values of the Company’s investments in marketable debt securities are determined using quoted market prices in active markets for identical assets or quoted prices for similar assets or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Changes in fair value that are not impairment related are reported net of taxes in OCI. The Company considers available evidence in evaluating potential impairments of its investments in marketable debt securities, including the extent to which fair value is less than cost, whether an allowance for credit loss is required, as well as adverse factors that could affect the value of the securities. An impairment has occurred if the Company does not expect to recover the entire amortized cost basis of the marketable debt security. If the Company does not intend to sell the impaired debt security, and it is not more likely than not it will be required to sell the debt security before the recovery of its amortized cost basis, the amount of the impairment recognized in earnings, recorded in Other (income) expense, net, is limited to the portion attributed to credit loss. The remaining portion of the impairment related to other factors is recognized in OCI. Realized gains and losses for debt securities are included in Other (income) expense, net.
Investments in publicly traded equity securities are reported at fair value as determined using quoted market prices in active markets for identical assets or quoted prices for similar assets or other inputs that are observable or can be corroborated by observable market data. Changes in fair value are included in Other (income) expense, net. Unrealized gains and losses from investments that are directly owned are determined at the end of the reporting period. Gains and losses from ownership interests in investment funds, which are accounted for as equity method investments, are reported on a one quarter lag. Investments in equity securities without readily determinable fair values are recorded at cost, plus or minus subsequent observable price changes in orderly transactions for identical or similar investments, minus impairments. Such adjustments are recognized in Other (income) expense, net. Realized gains and losses for equity securities are included in Other (income) expense, net.
Revenue Recognition
Revenue Recognition — Recognition of revenue requires evidence of a contract, probable collection of sales proceeds and completion of substantially all performance obligations. Merck acts as the principal in substantially all of its customer arrangements and therefore records revenue on a gross basis. The majority of the Company’s contracts related to the Pharmaceutical and Animal Health segments have a single performance obligation - the promise to transfer goods. Shipping is considered immaterial in the context of the overall customer arrangement and damages or loss of goods in transit are rare. Therefore, shipping is not deemed a separately recognized performance obligation.
The vast majority of revenues from sales of products are recognized at a point in time when control of the goods is transferred to the customer, which the Company has determined is when title and risks and rewards of ownership transfer to the customer and the Company is entitled to payment. The Company recognizes revenue from the sales of vaccines to the U.S. federal government for placement into vaccine stockpiles in accordance with Securities and Exchange Commission (SEC) Interpretation, Commission Guidance Regarding Accounting for Sales of Vaccines and BioTerror Countermeasures to the Federal Government for Placement into the Pediatric Vaccine Stockpile or the Strategic National Stockpile. This interpretation allows companies to recognize revenue for sales of vaccines into U.S. government stockpiles even though these sales might not meet the criteria for revenue recognition under other accounting guidance. For certain services in the Animal Health segment, revenue is recognized over time, generally ratably over the contract term as services are provided. These service revenues are not material.
The nature of the Company’s business gives rise to several types of variable consideration including discounts and returns, which are estimated at the time of sale generally using the expected value method, although the most likely amount method is used for prompt pay discounts.
In the U.S., sales discounts are issued to customers at the point-of-sale, through an intermediary wholesaler (known as chargebacks), or in the form of rebates. Additionally, sales are generally made with a limited right of return under certain conditions. Revenues are recorded net of provisions for sales discounts and returns, which are established at the time of sale. In addition, if collection of accounts receivable is expected to be in excess of one year, sales are recorded net of time value of money discounts, which have not been material.
The U.S. provision for aggregate customer discounts covering chargebacks and rebates was $10.0 billion in 2025, $13.3 billion in 2024 and $12.5 billion in 2023. Chargebacks are discounts that occur when a contracted customer purchases through an intermediary wholesaler. The wholesaler then charges the Company back for the difference between the price initially paid by the wholesaler and the contract price agreed to between Merck and the customer. The provision for chargebacks is based on expected sell-through levels by the Company’s wholesale customers to contracted customers, as well as estimated wholesaler inventory levels. Rebates are amounts 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 to a benefit plan participant. The provision for rebates is based on expected patient usage, as well as inventory levels in the distribution channel to determine the contractual obligation to the benefit providers. The Company uses historical customer segment utilization mix, sales forecasts, changes to product mix and price, inventory levels in the distribution channel, government pricing calculations and prior payment history in order to estimate the expected provision. Amounts accrued for aggregate customer discounts are evaluated on a quarterly basis through comparison of information provided by the wholesalers, health maintenance organizations, pharmacy benefit managers, federal and state agencies, and other customers to the amounts accrued. The accrued balances relative to the provisions for chargebacks and rebates included in Accounts receivable and Accrued and other current liabilities were $295 million and $1.5 billion, respectively, at December 31, 2025 and were $293 million and $2.2 billion, respectively, at December 31, 2024.
Outside of the U.S., variable consideration in the form of discounts and rebates are a combination of commercially-driven discounts in highly competitive product classes, discounts required to gain or maintain reimbursement, or legislatively mandated rebates. In certain European countries, legislatively mandated rebates are calculated based on an estimate of the government’s total unbudgeted health care spending and the Company’s specific payback obligation. Rebates may also be required based on specific product sales thresholds. The Company applies an estimated factor against its actual invoiced sales to represent the expected level of future discount or rebate obligations associated with the sale.
The Company maintains a returns policy that allows its U.S. pharmaceutical customers to return product within a specified period prior to and subsequent to the expiration date (generally, three to six months before and 12 months after product expiration). The estimate of the provision for returns is based upon historical experience with actual returns. Additionally, the Company considers factors such as levels of inventory in the distribution channel, product dating and expiration period, whether products have been discontinued, entrance in the market of generic or other competition, changes in formularies or launch of over-the-counter products, among others. Outside of the U.S., returns are only allowed in certain countries on a limited basis.
Merck’s payment terms for U.S. pharmaceutical products are typically 35 days from receipt of invoice and for U.S. animal health products are typically 30 days from receipt of invoice; however, certain products have longer payment terms, including Keytruda (pembrolizumab), which has payment terms of 90 days. Payment terms for vaccine products in the U.S. typically range from 30 days to 60 days. Outside of the U.S., payment terms are typically 30 days to 90 days, although certain markets have longer payment terms.
See Note 18 for disaggregated revenue disclosures.
Depreciation Depreciation — Depreciation is provided over the estimated useful lives of the assets, principally using the straight-line method. For tax purposes, accelerated tax methods are used. The estimated useful lives primarily range from 25 to 45 years for Buildings, and from 3 to 15 years for Machinery, equipment and office furnishings.
Advertising and Promotion Costs Advertising and Promotion Costs — Advertising and promotion costs are expensed as incurred.
Software Capitalization
Software Capitalization — The Company capitalizes certain costs incurred in connection with obtaining or developing internal-use software including external direct costs of material and services, and payroll costs for employees directly involved with the software development. These costs are included in Property, plant and equipment. The Company also capitalizes certain costs incurred to implement cloud computing arrangements, which
are considered service agreements. These costs are included in Other Assets. Capitalized software costs are being amortized over periods ranging from 2 to 10 years (which include contract renewal periods for cloud computing arrangements that are reasonably certain to occur), with the longer lives generally associated with enterprise-wide projects implemented over multiple years. Costs incurred during the preliminary project stage and post-implementation stage, as well as maintenance and training costs, are expensed as incurred.
Goodwill
Goodwill — Goodwill represents the excess of the consideration transferred over the fair value of net assets acquired in a business combination. Goodwill is assigned to reporting units and evaluated for impairment at least annually, or more frequently if impairment indicators exist, by first assessing qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If the Company concludes it is more likely than not that the fair value of a reporting unit is less than its carrying amount, a quantitative fair value test is performed. If the carrying value of a reporting unit is greater than its fair value, a goodwill impairment charge will be recorded for the difference (up to the carrying value of goodwill).
Acquired Intangibles
Acquired Intangibles — Intangibles acquired in business combinations and asset acquisitions include product rights, trade names and patents, licenses and other, which are initially recorded at fair value, assigned an estimated useful life, and amortized primarily on a straight-line basis over their estimated useful lives ranging from 2 to 24 years. The Company periodically evaluates whether current facts or circumstances indicate that the carrying values of its acquired intangibles may not be recoverable. If such circumstances are determined to exist, an estimate of the undiscounted future cash flows of these assets, or appropriate asset groupings, is compared to the carrying value to determine whether an impairment exists. If the asset is determined to be impaired, the loss is measured based on the difference between the carrying value of the intangible asset and its fair value, which is determined based on the net present value of estimated future cash flows.
Acquired In-Process Research and Development
Acquired In-Process Research and Development — IPR&D that the Company acquires in conjunction with a business combination represents the fair value assigned to incomplete research projects which, at the time of acquisition, have not reached technological feasibility. The amounts are capitalized and are accounted for as indefinite-lived intangible assets, subject to impairment testing until completion or abandonment of the projects. Upon successful completion of each IPR&D project, Merck will make a determination as to the then-useful life of the intangible asset, generally determined by the period in which the substantial majority of the cash flows are expected to be generated, and begin amortization. The Company evaluates IPR&D for impairment at least annually, or more frequently if impairment indicators exist, by performing a quantitative test that compares the fair value of the IPR&D intangible asset with its carrying value. If the fair value is less than the carrying amount, an impairment loss is recognized in operating results.
Contingent Consideration for Business Combinations Contingent Consideration for Business Combinations — Certain of the Company’s acquisitions involve the potential for future payment of consideration that is contingent upon the achievement of performance milestones, including product development milestones and royalty payments on future product sales. If the transaction is accounted for as a business combination, the fair value of contingent consideration liabilities is determined at the acquisition date using unobservable inputs. These inputs include the estimated amount and timing of projected cash flows, the probability of success (achievement of the contingent event) and the risk-adjusted discount rate used to present value the probability-weighted cash flows. Subsequent to the acquisition date, at each reporting period until the contingency is resolved, the contingent consideration liability is remeasured at current fair value with changes (either expense or income) recorded in earnings. Significant events that increase or decrease the probability of achieving development and regulatory milestones or that increase or decrease projected cash flows will result in corresponding increases or decreases in the fair values of the related contingent consideration obligations.
Research and Development Research and Development — Research and development is expensed as incurred. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Research and development expenses include restructuring costs and IPR&D impairment charges. In addition, research and development expenses include expense or income related to changes in the estimated fair value measurement of liabilities for contingent consideration associated with IPR&D assets. Research and development expenses also include upfront and milestone payments related to asset acquisitions and licensing transactions involving clinical development programs that have not yet received regulatory approval.
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. When Merck is the principal on sales transactions with third parties, the Company recognizes sales, cost of sales and selling, general and administrative expenses on a gross basis. Profit sharing amounts it pays to its collaborative partners are recorded within Cost of sales. When the collaborative partner is the principal on sales transactions with
third parties, the Company records profit sharing amounts received from its collaborative partners as alliance revenue (within Sales). Alliance revenue is recorded net of cost of sales and includes an adjustment to share commercialization costs between the partners in accordance with the collaboration agreement. The adjustment is determined by comparing the commercialization costs Merck has incurred directly and reported within Selling, general and administrative expenses with the costs the collaborative partner has incurred. Research and development costs Merck incurs related to collaborations are recorded within Research and development expenses. Cost reimbursements to the collaborative partner or payments received from the collaborative partner to share these costs pursuant to the terms of the collaboration agreements are recorded as increases or decreases to Research and development expenses, respectively.
In addition, the terms of the collaboration agreements may require the Company to make payments based upon the achievement of certain developmental, regulatory approval or commercial milestones. Upfront and milestone payments payable by Merck to collaborative partners prior to regulatory approval are expensed as incurred and included in Research and development expenses. Payments due to collaborative partners upon or subsequent to regulatory approval are capitalized and amortized to Cost of sales over the estimated useful life of the corresponding intangible asset, provided that future cash flows support the amounts capitalized. Sales-based milestones payable by Merck to collaborative partners are accrued and capitalized, subject to cumulative amortization catch-up, when determined by the Company to be probable of being achieved based on future sales forecasts. The amortization catch-up is calculated either from the time of the first regulatory approval for products that were unapproved at the time the collaboration was formed or, for new indications of approved products, from the time of the formation of the collaboration. The related intangible asset that is recognized is amortized to Cost of sales over its estimated remaining useful life, subject to impairment testing.
Share-Based Compensation
Share-Based Compensation — The Company expenses all share-based payments to employees over the requisite service period based on the grant-date fair value of the awards.
Restructuring Costs
Restructuring Costs — The Company records liabilities for costs associated with exit or disposal activities in the period in which the liability is incurred. In accordance with existing benefit arrangements, future employee termination costs to be incurred in conjunction with involuntary separations are accrued when such separations are probable and estimable. When accruing these costs, the Company will recognize the amount within a range of costs that is the best estimate within the range. When no amount within the range is a better estimate than any other amount, the Company recognizes the minimum amount within the range. Costs for one-time termination benefits in which the employee is required to render service until termination in order to receive the benefits are recognized ratably over the future service period.
Contingencies and Legal Defense Costs
Contingencies and Legal Defense Costs — The Company records accruals for contingencies and legal defense costs expected to be incurred in connection with a loss contingency when it is probable that a liability has been incurred and the amount can be reasonably estimated.
Taxes on Income
Taxes on Income — Deferred taxes are recognized for the future tax effects of temporary differences between financial and income tax reporting based on enacted tax laws and rates. The Company evaluates tax positions to determine whether the benefits of tax positions are more likely than not of being sustained upon audit based on the technical merits of the tax position. For tax positions that are more likely than not of being sustained upon audit, the Company recognizes the amount of the benefit that is greater than 50% likely of being realized upon ultimate settlement in the financial statements. For tax positions that are not more likely than not of being sustained upon audit, the Company does not recognize any portion of the benefit in the financial statements. The Company recognizes interest and penalties associated with uncertain tax positions as a component of Taxes on Income. The Company accounts for the tax effects of the tax on global intangible low-taxed income (GILTI) of certain foreign subsidiaries in the income tax provision in the period the tax arises. H.R. 1 - One Big Beautiful Bill Act (OBBBA) renamed the provision for taxes on foreign earnings from GILTI to net controlled foreign corporation tested income (NCTI). The Company’s policy for releasing disproportionate income tax effects from AOCL is to utilize the item-by-item approach.
Reclassifications Reclassifications — Certain reclassifications have been made to prior year amounts to conform to the current year presentation.
Use of Estimates
Use of Estimates — The consolidated financial statements are prepared in conformity with accounting principles generally accepted in the U.S. (GAAP) and, accordingly, include certain amounts that are based on management’s best estimates and judgments. Estimates are used when accounting for amounts recorded in connection with acquisitions, including initial fair value determinations of assets and liabilities in a business combination (primarily IPR&D, other intangible assets and contingent consideration), as well as subsequent fair value
measurements. Additionally, estimates are used in determining such items as provisions for sales discounts, rebates and returns, depreciable and amortizable lives, recoverability of inventories (including those produced in preparation for product launches), amounts recorded for contingencies, environmental liabilities, contingent sales-based milestone payments and other reserves, pension and other postretirement benefit plan assumptions, share-based compensation assumptions, restructuring costs, impairments of long-lived assets (including intangible assets and goodwill) and investments, and taxes on income. Because of the uncertainty inherent in such estimates, actual results may differ from these estimates.
Recently Adopted Accounting Standards and Recently Issued Accounting Standards Not Yet Adopted
Recently Adopted Accounting Standards — 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 Company elected to prospectively adopt the guidance effective for 2025 annual reporting. The adoption primarily resulted in incremental disclosures to the Company’s income tax disclosures contained in Note 15.
In September 2025, the FASB issued amended guidance to reduce the complexity of evaluating whether contracts are derivatives by adding a scope exception (which may apply to certain R&D funding arrangements) to exclude from derivative accounting non-exchange-traded contracts with variables (underlyings) that are based on operations or activities specific to one of the parties to the contract. The Company adopted the guidance on October 1, 2025, effective for full year 2025 on a prospective basis. The Company did not have any contracts that were affected by the adoption of this new standard; therefore, there was no impact to the Company’s consolidated financial statements upon adoption.
Recently Issued Accounting Standards Not Yet Adopted — In November 2024, the FASB issued guidance intended to improve financial reporting by requiring entities to disclose additional information about specific expense categories for interim and annual reporting periods. The guidance is effective for 2027 annual reporting and 2028 interim reporting. Early adoption is permitted. The guidance, which can be applied on a prospective or retrospective basis, will result in incremental disclosures within the footnotes to the Company’s financial statements.
In December 2025, the FASB issued guidance that includes requirements for recognition of government grants in a Company’s financial statements as well as disclosure requirements, including the nature of the government grant received, the accounting policies used to account for the grant, and significant terms and conditions of the grant. The guidance is effective for 2029 interim and annual reporting on a modified prospective, modified retrospective or retrospective approach. Early adoption is permitted as of the beginning of an annual reporting period. The Company is currently evaluating the impact of adoption on its consolidated financial statements.
Legal Costs Legal defense costs expected to be incurred in connection with a loss contingency are accrued when probable and reasonably estimable.
v3.25.4
Acquisitions, Research Collaborations and Licensing Agreements (Tables)
12 Months Ended
Dec. 31, 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:
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.
v3.25.4
Collaborative Arrangements (Tables)
12 Months Ended
Dec. 31, 2025
Collaborative Arrangements [Abstract]  
Collaborative Arrangements
Summarized financial information related to this collaboration is as follows:
Years Ended December 31202520242023
Alliance revenue - Lynparza$1,450 $1,311 $1,199 
Alliance revenue - Koselugo (1)
436 170 97 
Total alliance revenue$1,886 $1,481 $1,296 
Cost of sales (2)
338 378 311 
Selling, general and administrative133 165 192 
Research and development36 77 79 
December 3120252024
Receivables from AstraZeneca included in Other current assets (3)
$451 $424 
Receivables from AstraZeneca included in Other assets (3)
125 — 
Payables to AstraZeneca included in Accrued and other current liabilities (4)
6 713 
(1)    Amounts in 2025 include the $150 million upfront payment and $175 million regulatory milestones triggered as a result of the amendment to the collaboration agreement noted above.
(2)    Represents amortization of capitalized milestone payments. Amount in 2024 includes $48 million of cumulative amortization catch-up expense as noted above.
(3)    Balance at December 31, 2025 includes milestone receivables.
(4)    Balance at December 31, 2024 includes accrued milestone payments.
Summarized financial information related to this collaboration is as follows:
Years Ended December 31202520242023
Alliance revenue - Lenvima$1,053 $1,010 $960 
Cost of sales (1)
241 241 381 
Selling, general and administrative134 159 189 
Research and development11 21 66 
December 3120252024
Receivables from Eisai included in Other current assets
$271 $257 
(1)     Represents amortization of capitalized milestone payments. Amount in 2023 includes $154 million of cumulative amortization catch-up expense as noted above.
Summarized financial information related to this collaboration is as follows:
Years Ended December 31202520242023
Alliance revenue - Adempas/Verquvo$470 $415 $367 
Net sales of Adempas recorded by Merck312 287 255 
Net sales of Verquvo recorded by Merck48 37 36 
Total sales$830 $739 $658 
Cost of sales (1)
256 244 224 
Selling, general and administrative97 111 131 
Research and development56 102 90 
December 3120252024
Receivables from Bayer included in Other current assets
$167 $160 
Payables to Bayer included in Accrued and other current liabilities
81 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:
Years Ended December 31202520242023
Net sales of Lagevrio recorded by Merck
$380 $964 $1,428 
Cost of sales (1)
235 554 852 
Selling, general and administrative
54 57 97 
Research and development
31 13 60 
December 3120252024
Receivables from Ridgeback included in Other current assets
$27 $— 
Payables to Ridgeback included in Accrued and other current liabilities (2)
11 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:
Years Ended December 31202520242023
Cost of sales (1)
$66 $— $— 
Selling, general and administrative
28 26 
Research and development (2)
524 351 5,549 
December 3120252024
Receivables from Daiichi Sankyo included in Other current assets
$15 $
Payables to Daiichi Sankyo included in Accrued and other current liabilities (3)
113 817 
(1)    Represents Merck’s share of certain inventory-related costs.
(2)    Expenses in 2023 include the $5.5 billion charge for the upfront and continuing option payments noted above.
(3)    Balance at December 31, 2024 includes accrued continuation payment.
Summarized financial information related to this collaboration is as follows:
Years Ended December 31202520242023
Selling, general and administrative
$27 $16 $
Research and development (1)
375 358 218 
December 3120252024
Payables to Moderna included in Accrued and other current liabilities
$13 $57 
(1)    Includes amortization of shared facility costs.
v3.25.4
Restructuring (Tables)
12 Months Ended
Dec. 31, 2025
Restructuring and Related Activities [Abstract]  
Schedule of Charges Related to Restructuring Program Activities by Type of Cost
The following table summarizes the charges related to restructuring program activities by type of cost:
Accelerated
Depreciation
Separation
Costs
Other Exit Costs
Total
Year Ended December 31, 2025
2025 Restructuring Program
Cost of sales$910 $ $322 $1,232 
Selling, general and administrative
  2 2 
Research and development
  175 175 
Restructuring costs 548 55 603 
910 548 554 2,012 
2024 Restructuring Program
Cost of sales247  5 252 
Selling, general and administrative  1 1 
Restructuring costs 61 225 286 
247 61 231 539 
$1,157 $609 $785 $2,551 
Year Ended December 31, 2024
2024 Restructuring Program
Cost of sales$254 $— $241 $495 
Selling, general and administrative— — 83 83 
Research and development— — 
Restructuring costs— 122 187 309 
$254 $122 $512 $888 
Year Ended December 31, 2023
2024 Restructuring Program
Cost of sales$— $— $62 $62 
Restructuring costs— 115 13 128 
— 115 75 190 
2019 Restructuring Program
Cost of sales131 — 18 149 
Selling, general and administrative— 113 122 
Research and development— — 
Restructuring costs— 339 132 471 
 140 339 264 743 
$140 $454 $339 $933 
Schedule of Charges and Spending Relating to Restructuring Activities by Program
The following table summarizes the charges and spending related to restructuring program activities:
Accelerated
Depreciation
Separation
Costs
Other Exit Costs
Total
2025 Restructuring Program
Restructuring reserves January 1, 2025$— $— $— $— 
Expenses910 548 554 2,012 
(Payments) receipts, net (46)(50)(96)
Non-cash activity(910) (216)(1,126)
Restructuring reserves December 31, 2025$ $502 $288 $790 
2024 Restructuring Program
Restructuring reserves January 1, 2024
$— $681 $31 $712 
Expenses254 122 512 888 
(Payments) receipts, net— (239)(206)(445)
Non-cash activity(254)— (337)(591)
Restructuring reserves December 31, 2024
— 564 — 564 
Expenses247 61 231 539 
(Payments) receipts, net (119)(210)(329)
Non-cash activity(247) (21)(268)
Restructuring reserves December 31, 2025
$ $506 $ $506 
v3.25.4
Financial Instruments (Tables)
12 Months Ended
Dec. 31, 2025
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of Effect of Net Investment Hedges
The effects of the Company’s net investment hedges on OCI and the Consolidated Statement of Income are shown below:
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income (1)
Amount of Pretax (Gain) Loss Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing
Years Ended December 31202520242023202520242023
Net Investment Hedging Relationships
Foreign exchange contracts$32 $(30)$— $(15)$(4)$
Euro-denominated notes591 (192)105  — — 
(1)    No amounts were reclassified from AOCL into income related to the sale of a subsidiary.
Schedule of Interest Rate Derivatives
At December 31, 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.
Par Value of DebtNumber of Interest Rate Swaps HeldTotal Swap Notional Amount
4.50% notes due 2033
$1,500 $1,500 
5.00% notes due 2053
1,500 250 
Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position
The table below presents the location of amounts recorded in the Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges as of December 31:
Carrying Amount of Hedged Liabilities
Cumulative Amount of Fair Value Hedging Adjustment Increase Included in the Carrying Amount
2025202420252024
Balance Sheet Caption
Long-Term Debt $1,810 $1,509 $70 $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 as of December 31:
  20252024
  Fair Value of
Derivative
U.S. Dollar
Notional
Fair Value of
Derivative
U.S. Dollar
Notional
 AssetLiabilityAssetLiability
Derivatives Designated as Hedging InstrumentsBalance Sheet Caption      
Interest rate swap contracts
Other Assets
$71 $ $1,750 $17 $— $1,500 
Foreign exchange contractsOther current assets113  6,430 323 — 8,662 
Foreign exchange contractsOther Assets32  1,793 66 — 2,125 
Foreign exchange contractsAccrued and other current liabilities 131 4,726 — 162 
Foreign exchange contractsOther Noncurrent Liabilities 1 13 — 16 
  $216 $132 $14,712 $406 $$12,465 
Derivatives Not Designated as Hedging InstrumentsBalance Sheet Caption      
Foreign exchange contractsOther current assets$107 $ $11,643 $323 $— $12,544 
Foreign exchange contractsAccrued and other current liabilities 191 13,579 — 343 13,551 
Foreign exchange contractsOther Noncurrent Liabilities 1 357 — — — 
  $107 $192 $25,579 $323 $343 $26,095 
  $323 $324 $40,291 $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 as of December 31:
20252024
AssetLiabilityAssetLiability
Gross amounts recognized in the consolidated balance sheet$323 $324 $729 $345 
Gross amounts subject to offset in master netting arrangements not offset in the consolidated balance sheet(245)(245)(299)(299)
Cash collateral received
(1) (165)— 
Net amounts$77 $79 $265 $46 
Schedule of Location and Pretax Gain or Loss Amounts for 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:
Years Ended December 31202520242023202520242023202520242023
Financial Statement Caption in which Effects of Fair Value or Cash Flow Hedges are RecordedSales
Other (income) expense, net (1)
Other comprehensive income (loss)
$65,011 $64,168 $60,115 $151 $(24)$466 $658 $216 $(393)
Loss (gain) on fair value hedging relationships:
Interest rate swap contracts
Hedged items — — 53 (39)56  — — 
Derivatives designated as hedging instruments — — (54)39 (57) — — 
Impact of cash flow hedging relationships:
Foreign exchange contracts
Amount of (loss) gain recognized in OCI on derivatives
 — —  — — (577)508 114 
(Decrease) increase in Sales as a result of AOCL reclassifications
(106)167 249  — — 106 (167)(249)
Interest rate contracts
Amount of gain recognized in Other (income) expense, net on derivatives
 — — (1)(1)(1) — — 
Amount of gain (loss) recognized in OCI on derivatives
 — —  — — 28 (1)13 
(1)    Interest expense is a component of Other (income) expense, net.
Schedule of Income Statement Effects of Derivatives Not Designated as Hedging Instruments
The table below provides information regarding the income statement effects of derivatives not designated as hedging instruments:
Amount of Derivative Pretax (Gain) Loss Recognized in Income
Years Ended December 31202520242023
Derivatives Not Designated as Hedging InstrumentsIncome Statement Caption
Foreign exchange contracts (1)
Other (income) expense, net$(196)$251 $(6)
Foreign exchange contracts (2)
Sales21 (28)
(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 at December 31 is as follows:
 
 20252024
 Amortized
Cost
Gross UnrealizedFair
Value
Amortized
Cost
Gross UnrealizedFair
Value
GainsLossesGainsLosses
U.S. government and agency securities$100 $ $ $100 $188 $— $— $188 
Foreign government bonds
1   1 — — — — 
Commercial paper    348 — — 348 
Total debt securities$101 $ $ $101 $536 $— $— $536 
Publicly traded equity securities (1)
1,392 920 
Total debt and publicly traded equity securities$1,493 $1,456 
(1)    Unrealized net gains of $474 million were recorded in Other (income) expense, net in 2025 on equity securities still held at December 31, 2025. Unrealized net losses of $30 million were recorded in Other (income) expense, net in 2024 on equity securities still held at December 31, 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 at December 31 are summarized below:
 Fair Value Measurements UsingFair Value Measurements Using
Level 1Level 2Level 3TotalLevel 1Level 2Level 3Total
  20252024
Assets
Investments
Foreign government bonds
$ $1 $ $1 $— $— $— $— 
Commercial paper    — 348 — 348 
U.S. government and agency securities    — 99 — 99 
Publicly traded equity securities955   955 463 — — 463 
 955 1  956 463 447 — 910 
Other assets (1)
U.S. government and agency securities100   100 89 — — 89 
Publicly traded equity securities (2)
437   437 457 — — 457 
537   537 546 — — 546 
Derivative assets (3)
Forward exchange contracts 168  168 — 499 — 499 
Purchased currency options 84  84 — 213 — 213 
Interest rate swaps 71  71 — 17 — 17 
  323  323 — 729 — 729 
Total assets$1,492 $324 $ $1,816 $1,009 $1,176 $— $2,185 
Liabilities
Other liabilities
Contingent consideration$ $ $ $ $— $— $193 $193 
Derivative liabilities (3)
Forward exchange contracts 293  293 — 338 — 338 
Written currency options 31  31 — — 
 324  324 — 345 — 345 
Total liabilities$ $324 $ $324 $— $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)    Balance at December 31, 2024 includes securities with an aggregate fair value of $81 million, 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 Summarized 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:
20252024
Fair value January 1$193 $354 
Changes in estimated fair value (1)
(52)(10)
Payments (2)
(141)(151)
Fair value December 31
$ $193 
(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 (ceftolozane and tazobactam) 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 and amount in 2024 also includes a $25 million payment related to the first commercial sale of Lyfnua (gefapixant) in the European Union.
v3.25.4
Inventories (Tables)
12 Months Ended
Dec. 31, 2025
Inventory Disclosure [Abstract]  
Schedule of Inventory, current
Inventories at December 31 consisted of:
20252024
Finished goods$2,275 $2,022 
Raw materials and work in process10,645 8,831 
Supplies331 289 

13,251 11,142 
Decrease to LIFO cost(912)(840)
 $12,339 $10,302 
Recognized as:
Inventories$6,658 $6,109 
Other Assets5,681 4,193 
Schedule of Inventory, noncurrent
Inventories at December 31 consisted of:
20252024
Finished goods$2,275 $2,022 
Raw materials and work in process10,645 8,831 
Supplies331 289 

13,251 11,142 
Decrease to LIFO cost(912)(840)
 $12,339 $10,302 
Recognized as:
Inventories$6,658 $6,109 
Other Assets5,681 4,193 
v3.25.4
Goodwill and Other Intangibles (Tables)
12 Months Ended
Dec. 31, 2025
Goodwill and Intangible Assets Disclosure [Abstract]  
Schedule of Goodwill Activity by Segment
The following table summarizes goodwill activity by segment:
PharmaceuticalAnimal HealthTotal
Balance January 1, 2024
$17,922 $3,275 $21,197 
Acquisitions (1)
— 518 518 
Other (2)
(19)(28)(47)
Balance December 31, 2024 (3)
17,903 3,765 21,668 
Acquisitions (1)
 (106)(106)
Other (2)
2 15 17 
Balance December 31, 2025 (3)
$17,905 $3,674 $21,579 
(1)    Activity is related to the 2024 acquisition of the Elanco aqua business and related measurement period adjustments in 2025.
(2)    Includes cumulative translation adjustments on goodwill balances.
(3)    Accumulated goodwill impairment losses were $531 million at both December 31, 2025 and 2024.
Schedule of Other Intangibles
Other acquired intangibles at December 31 consisted of:
 20252024
Gross
Carrying
Amount
Accumulated
Amortization
NetGross
Carrying
Amount
Accumulated
Amortization
Net
Product rights
$42,038 $20,710 $21,328 $29,988 $19,066 $10,922 
IPR&D427  427 430 — 430 
Trade names2,881 1,158 1,723 2,881 954 1,927 
Licenses and other10,064 6,861 3,203 8,863 5,772 3,091 
 $55,410 $28,729 $26,681 $42,162 $25,792 $16,370 
v3.25.4
Loans Payable, Long-Term Debt and Leases (Tables)
12 Months Ended
Dec. 31, 2025
Debt Disclosure [Abstract]  
Schedule of Long-term Debt
Long-term debt at December 31 consisted of:
20252024
2.15% notes due 2031
$1,991 $1,989 
2.75% notes due 2051
1,981 1,980 
3.70% notes due 2045
1,981 1,980 
3.40% notes due 2029
1,744 1,742 
4.95% notes due 2035
1,739 — 
4.50% notes due 2033
1,553 1,509 
1.70% notes due 2027
1,498 1,497 
5.00% notes due 2053
1,492 1,482 
4.75% notes due 2035
1,486 — 
2.90% notes due 2061
1,485 1,484 
5.55% notes due 2055
1,477 — 
4.00% notes due 2049
1,475 1,474 
1.45% notes due 2030
1,242 1,240 
4.15% notes due 2043
1,241 1,240 
5.70% notes due 2055
1,235 — 
2.45% notes due 2050
1,217 1,216 
1.90% notes due 2028
997 996 
4.55% notes due 2032
995 — 
4.45% notes due 2032
994 — 
4.15% notes due 2031
994 — 
3.25% euro-denominated notes due 2032
993 880 
3.50% euro-denominated notes due 2037
990 877 
5.15% notes due 2063
988 987 
3.90% notes due 2039
988 987 
3.70% euro-denominated notes due 2044
988 876 
2.35% notes due 2040
987 986 
3.75% euro-denominated notes due 2054
985 873 
5.70% notes due 2065
984 — 
4.30% notes due 2030
747 746 
3.85% notes due 2027
747 — 
3.85% notes due 2029
746 — 
4.15% notes due 2030
745 — 
5.50% notes due 2046
742 — 
4.90% notes due 2044
740 740 
6.50% notes due 2033
698 702 
1.375% euro-denominated notes due 2036
583 517 
2.50% euro-denominated notes due 2034
583 517 
4.05% notes due 2028
499 498 
Floating rate notes due 2027 (1)
499 — 
Floating rate notes due 2029 (2)
498 — 
3.60% notes due 2042
493 492 
6.55% notes due 2037
402 404 
5.75% notes due 2036
339 339 
5.95% debentures due 2028
308 307 
5.85% notes due 2039
271 271 
6.40% debentures due 2028
251 251 
1.875% euro-denominated notes due 2026
 1,041 
0.75% notes due 2026
 998 
6.30% debentures due 2026
 135 
Other139 209 
$46,750 $34,462 
(1)    Floating rate is compounded SOFR plus 46 bps, which at December 31, 2025 was 4.16%.
(2)    Floating rate is compounded SOFR plus 57 bps, which at December 31, 2025 was 4.35%.
Schedule of Supplemental Balance Sheet Information
Supplemental balance sheet information related to operating leases is as follows:
December 3120252024
Assets
Other Assets (1)
$1,507 $1,370 
Liabilities
Accrued and other current liabilities294 282 
Other Noncurrent Liabilities901 877 
$1,195 $1,159 
Weighted-average remaining lease term (years)7.06.0
Weighted-average discount rate3.5 %3.2 %
(1)    Includes prepaid leases that have no related lease liability.
Schedule of Maturities of Operating Lease Liabilities
Maturities of operating leases liabilities are as follows:
2026$335 
2027261 
2028204 
2029125 
2030103 
Thereafter415 
Total lease payments1,443 
Less: Imputed interest248 
$1,195 
v3.25.4
Equity (Tables)
12 Months Ended
Dec. 31, 2025
Equity [Abstract]  
Schedule of Common Stock and Treasury Stock Transactions
A summary of common stock and treasury stock transactions (shares in millions) is as follows:
 202520242023
  Common
Stock
Treasury
Stock
Common
Stock
Treasury
Stock
Common
Stock
Treasury
Stock
Balance January 13,577 1,049 3,577 1,045 3,577 1,039 
Purchases of treasury stock 59 — 11 — 13 
Issuances (1)
 (6)— (7)— (7)
Balance December 313,577 1,102 3,577 1,049 3,577 1,045 
(1)    Issuances primarily reflect activity under share-based compensation plans.
v3.25.4
Share-Based Compensation Plans (Tables)
12 Months Ended
Dec. 31, 2025
Share-Based Payment Arrangement [Abstract]  
Schedule of Assumptions Used to Determine Weighted-Average Fair Value of Options Granted The weighted average fair value of options granted in 2025, 2024 and 2023 was $18.61, $25.60 and $21.69 per option, respectively, and were determined using the following assumptions:
Years Ended December 31202520242023
Expected dividend yield3.1 %3.0 %3.1 %
Risk-free interest rate3.9 %4.7 %3.4 %
Expected volatility25.9 %20.5 %22.4 %
Expected life (years)5.85.85.8
Schedule of Summarized Information Relative to Stock Option Plan Activity
Summarized information relative to stock option plan activity (options in thousands) is as follows:
Number
of Options
Weighted
Average
Exercise
Price
Weighted
Average
Remaining
Contractual
Term (Years)
Aggregate
Intrinsic
Value
Outstanding January 1, 2025
12,500 $86.04 
Granted1,616 84.71 
Exercised(1,428)64.76 
Forfeited(211)106.46   
Outstanding December 31, 2025
12,477 $87.95 5.7$275 
Vested and expected to vest December 31, 202512,235 $87.73 5.7$272 
Exercisable December 31, 20259,348 $82.09 4.8$244 
Schedule of Additional Information Pertaining to Stock Option Plans
Additional information pertaining to stock option plans is provided in the table below:
Years Ended December 31202520242023
Total intrinsic value of stock options exercised$41 $144 $95 
Fair value of stock options vested36 32 30 
Cash received from the exercise of stock options92 177 125 
Schedule of Nonvested RSU and PSU Activity
A summary of nonvested RSU and PSU activity (shares in thousands) is as follows:
 RSUsPSUs
  Number
of Shares
Weighted
Average
Grant Date
Fair Value
Number
of Shares
Weighted
Average
Grant Date
Fair Value
Nonvested January 1, 2025
12,232 $117.94 1,766 $117.57 
Granted10,318 84.65 1,233 81.20 
Vested(6,042)110.84 (1,101)88.42 
Forfeited(786)104.44 (64)104.87 
Nonvested December 31, 202515,722 $99.50 1,834 $111.13 
Expected to vest December 31, 202513,978 $100.27 1,732 $111.82 
v3.25.4
Pension and Other Postretirement Benefit Plans (Tables)
12 Months Ended
Dec. 31, 2025
Retirement Benefits [Abstract]  
Components of Net Periodic Benefit Cost
The net periodic benefit cost (credit) for pension and other postretirement benefit plans consisted of the following components:
Pension Benefits
U.S.InternationalOther Postretirement Benefits
Years Ended December 31202520242023202520242023202520242023
Service cost$378 $373 $326 $228 $243 $196 $37 $30 $32 
Interest cost569 537 526 303 294 299 61 56 63 
Expected return on plan assets(840)(826)(735)(613)(554)(517)(50)(80)(64)
Amortization of unrecognized prior service (credit) cost
 — (1)(28)(13)(40)(43)(49)
Net loss (gain) amortization58 43 — 11 (3)(45)(51)(42)
Termination benefits2  —  — 
Curtailments9 — (15)— (1)(3)— (1)
Settlements — 28  (1)(5) — — 
Net periodic benefit cost (credit)$176 $132 $155 $(114)$(25)$(29)$(40)$(84)$(61)
Obligation and Funded Status
Summarized information about the changes in plan assets and benefit obligations, the funded status and the amounts recorded at December 31 is as follows:
Pension BenefitsOther
Postretirement
Benefits
U.S.International
202520242025202420252024
Fair value of plan assets January 1$9,717 $9,804 $9,647 $9,562 $1,040 $1,045 
Actual return on plan assets1,435 266 318 637 86 35 
Company contributions267 262 195 198 71 46 
Effects of exchange rate changes — 1,010 (522) — 
Benefits paid(689)(615)(268)(250)(90)(89)
Settlements — (38)(14) — 
Other — 42 36  
Fair value of plan assets December 31$10,730 $9,717 $10,906 $9,647 $1,107 $1,040 
Benefit obligation January 1$10,151 $10,446 $8,274 $9,042 $1,136 $1,104 
Service cost378 373 228 243 37 30 
Interest cost569 537 303 294 61 56 
Actuarial losses (gains) (1)
178 (595)(962)(549)34 32 
Benefits paid(689)(615)(268)(250)(90)(89)
Effects of exchange rate changes — 879 (473)3 (4)
Plan amendments — (5)(56) — 
Curtailments9 — (4)— (2)— 
Termination benefits2   
Settlements — (38)(14) — 
Other — 45 36  
Benefit obligation December 31$10,598 $10,151 $8,452 $8,274 $1,179 $1,136 
Funded status December 31$132 $(434)$2,454 $1,373 $(72)$(96)
Recognized as:
Other Assets$602 $26 $2,770 $1,785 $66 $51 
Accrued and other current liabilities(58)(55)(20)(18)(7)(7)
Other Noncurrent Liabilities(412)(405)(296)(394)(131)(140)
(1)    Actuarial losses (gains) primarily reflect changes in discount rates.
Funded Status of Selected Pension Plans
Information related to the funded status of select pension plans at December 31 is as follows:
U.S.International
2025202420252024
Pension plans with a projected benefit obligation in excess of plan assets
Projected benefit obligation
$469 $9,517 $1,405 $1,847 
Fair value of plan assets 9,057 1,089 1,435 
Pension plans with an accumulated benefit obligation in excess of plan assets
Accumulated benefit obligation$449 $442 $1,332 $1,768 
Fair value of plan assets — 1,038 1,385 
Funded Status of Selected Pension Plans
Information related to the funded status of select pension plans at December 31 is as follows:
U.S.International
2025202420252024
Pension plans with a projected benefit obligation in excess of plan assets
Projected benefit obligation
$469 $9,517 $1,405 $1,847 
Fair value of plan assets 9,057 1,089 1,435 
Pension plans with an accumulated benefit obligation in excess of plan assets
Accumulated benefit obligation$449 $442 $1,332 $1,768 
Fair value of plan assets — 1,038 1,385 
Schedule of Allocation of Plan Assets
The fair values of the Company’s pension plan assets at December 31 by asset category are as follows:
 Fair Value Measurements UsingFair Value Measurements Using
Level 1Level 2Level 3
NAV (1)
TotalLevel 1Level 2Level 3
NAV (1)
Total
20252024
U.S. Pension Plans
Cash and cash equivalents$200 $ $ $142 $342 $43 $— $— $121 $164 
Investment funds
Developed markets equities196   3,278 3,474 170 — — 2,385 2,555 
Emerging markets equities   905 905 — — — 1,265 1,265 
Real estate   298 298 — — — 174 174 
Equity securities
Developed markets2,109    2,109 2,171 — — — 2,171 
Fixed income securities
Government and agency obligations 2,206   2,206 — 2,101 — — 2,101 
Corporate obligations 1,397   1,397 — 1,293 — — 1,293 
Mortgage and asset-backed securities 18   18 — 21 — — 21 
Other investments (liabilities)
Derivatives(21)   (21)(29)— — — (29)
Other  2  2 — — — 
Plan assets at fair value$2,484 $3,621 $2 $4,623 $10,730 $2,355 $3,415 $$3,945 $9,717 
International Pension Plans
Cash and cash equivalents$90 $5 $ $11 $106 $112 $— $— $11 $123 
Investment funds
Developed markets equities815 4,024  135 4,974 599 3,537 — 96 4,232 
Government and agency obligations323 3,306  157 3,786 262 2,974 — 149 3,385 
Corporate obligations25 10  156 191 23 — 149 180 
Emerging markets equities71   90 161 54 — — 91 145 
Other fixed income obligations27 5  4 36 — 19 
Real estate   17 17 — — — 12 12 
Equity securities
Developed markets289    289 287 — — — 287 
Fixed income securities
Government and agency obligations 413   413 — 368 — — 368 
Corporate obligations 147   147 — 141 — — 141 
Mortgage and asset-backed securities 51   51 — 54 — — 54 
Other investments
Insurance contracts (2)
  735  735 — 698 701 
Plan assets at fair value$1,640 $7,961 $735 $570 $10,906 $1,345 $7,090 $698 $514 $9,647 
(1)    Certain investments that were measured at net asset value (NAV) per share or its equivalent have not been classified in the fair value hierarchy. The NAV amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the fair value of plan assets at December 31, 2025 and 2024.
(2)    The plans’ Level 3 investments in insurance contracts are generally valued using a crediting rate that approximates market returns and invest in underlying securities whose market values are unobservable and determined using pricing models, discounted cash flow methodologies, or similar techniques.
The fair values of the Company’s other postretirement benefit plan assets at December 31 by asset category are as follows:
 Fair Value Measurements UsingFair Value Measurements Using
Level 1Level 2Level 3
NAV (1)
TotalLevel 1Level 2Level 3
NAV (1)
Total
20252024
Cash and cash equivalents$14 $ $ $4 $18 $— $— $— $$
Investment funds
Developed markets equities3   58 61 — — 46 49 
Emerging markets equities   16 16 — — — 24 24 
Real estate   5 5 — — — 
Equity securities
Developed markets38    38 41 — — — 41 
Fixed income securities
Corporate obligations 645   645 — 598 — — 598 
Government and agency obligations 261   261 — 266 — — 266 
Mortgage and asset-backed securities 63   63 — 54 — — 54 
Plan assets at fair value$55 $969 $ $83 $1,107 $44 $918 $— $78 $1,040 
(1)    Certain investments that were measured at net asset value (NAV) per share or its equivalent have not been classified in the fair value hierarchy. The NAV amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the fair value of plan assets at December 31, 2025 and 2024.
Summary of Changes in Fair Value of Company's Level 3 Pension Plan Assets
The table below provides a summary of the changes in fair value, including transfers in and/or out, of all financial assets measured at fair value using significant unobservable inputs (Level 3) for the Company’s pension plan assets:
 20252024
Insurance
Contracts
OtherTotalInsurance
Contracts
OtherTotal
U.S. Pension Plans
Balance January 1$ $2 $2 $— $$
Actual return on plan assets:
Relating to assets still held at December 31   — (2)(2)
Relating to assets sold during the year   — 
Purchases and sales, net   — (1)(1)
Balance December 31$ $2 $2 $— $$
International Pension Plans
Balance January 1$698 $ $698 $785 $— $785 
Actual return on plan assets:
Relating to assets still held at December 31117  117 (26)— (26)
Purchases and sales, net(85) (85)(61)— (61)
Transfers into Level 3
5  5 — — — 
Balance December 31$735 $ $735 $698 $— $698 
Summary of Expected Benefit Payments
Expected benefit payments are as follows:
U.S. Pension BenefitsInternational Pension
Benefits
Other
Postretirement
Benefits
2026$834 $334 $88 
2027832 323 90 
2028833 336 94 
2029847 354 98 
2030866 362 102 
2031 — 20354,531 2,108 554 
Components of Other Comprehensive Income (Loss) The following amounts were reflected as components of OCI:
 Pension PlansOther Postretirement
Benefit Plans
U.S.International
Years Ended December 31202520242023202520242023202520242023
Net gain (loss) arising during the period$408 $35 $(69)$686 $634 $(438)$2 $(78)$110 
Prior service credit (cost) arising during the period — — 5 56 (16) — — 
 $408 $35 $(69)$691 $690 $(454)$2 $(78)$110 
Net loss (gain) amortization included in benefit cost$58 $43 $— $11 $$(3)$(45)$(51)$(42)
Prior service (credit) cost amortization included in benefit cost — (1)(28)(13)(40)(43)(49)
Settlements and curtailments9 — 36 (15)(1)(6)(3)— (1)
 $67 $43 $35 $(32)$(9)$(7)$(88)$(94)$(92)
Summary of Weighted Average Assumptions Used in Determining Pension Plan and U.S. Pension and Other Postretirement Benefit Plan Information
The Company reassesses its benefit plan assumptions on a regular basis. The weighted average assumptions used in determining U.S. pension and other postretirement benefit plan and international pension plan information are as follows:
 U.S. Pension and Other
Postretirement Benefit Plans
International Pension Plans
December 31202520242023202520242023
Net periodic benefit cost      
Discount rate5.70 %5.30 %5.50 %3.70 %3.40 %3.90 %
Expected rate of return on plan assets7.70 %7.75 %7.00 %5.40 %5.20 %5.00 %
Salary growth rate4.80 %4.60 %4.60 %3.10 %3.20 %3.20 %
Interest crediting rate5.40 %5.30 %5.30 %3.50 %3.40 %3.30 %
Benefit obligation      
Discount rate5.60 %5.70 %5.30 %4.20 %3.70 %3.40 %
Salary growth rate4.80 %4.80 %4.60 %3.10 %3.10 %3.20 %
Interest crediting rate5.40 %5.40 %5.30 %3.70 %3.50 %3.40 %
Summary of Health Care Cost Trend Rate Assumptions for Other Postretirement Benefit Plans
The health care cost trend rate assumptions for other postretirement benefit plans are as follows:
December 3120252024
Health care cost trend rate assumed for next year8.50 %7.90 %
Rate to which the cost trend rate is assumed to decline4.50 %4.50 %
Year that the trend rate reaches the ultimate trend rate20412040
v3.25.4
Other (Income) Expense, Net (Tables)
12 Months Ended
Dec. 31, 2025
Other Income and Expenses [Abstract]  
Other (Income) Expense, Net
Other (income) expense, net, consisted of:
Years Ended December 31202520242023
Interest income$(343)$(415)$(365)
Interest expense1,357 1,271 1,146 
Exchange losses323 227 370 
Income from investments in equity securities, net (1)
(368)(14)(340)
Net periodic defined benefit plan (credit) cost other than service cost(615)(633)(498)
Other, net(203)(460)153 
 $151 $(24)$466 
(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.
v3.25.4
Taxes on Income (Tables)
12 Months Ended
Dec. 31, 2025
Income Tax Disclosure [Abstract]  
Schedule of Reconciliation Between Effective Tax Rate and U.S. Statutory Rate
A reconciliation between the effective income tax rate and the U.S. statutory rate (in accordance with the new guidance) for 2025 is as follows:
2025
AmountTax Rate
U.S. statutory rate applied to income before taxes$4,424 21.0 %
Differential arising from:
State and local income taxes, net of federal benefit (1)
12 0.1 
Foreign tax effects:
Switzerland
Tax rate differential between Switzerland and the U.S.(1,428)(6.8)
Withholding taxes284 1.3 
Other (2)
59 0.3 
Netherlands
Tax rate differential between Netherlands and the U.S.409 1.9 
Innovation box(1,042)(4.9)
Other(66)(0.3)
Other foreign jurisdictions308 1.5 
Effect of cross-border tax laws:
Net controlled foreign corporation tested income3,759 17.8 
Foreign-derived deduction-eligible income(31)(0.1)
Subpart F227 1.1 
Tax credits:
Foreign tax credits(4,190)(19.9)
Research and development tax credits(260)(1.2)
Valuation allowances76 0.4 
Nontaxable or nondeductible items(78)(0.4)
Changes in unrecognized tax benefits341 1.5 
$2,804 13.3 %
(1)    State and local tax expense was not material in 2025.
(2)    Includes the impact of Cantonal tax holiday and OECD Pillar 2.
A reconciliation between the effective income tax rate and the U.S. statutory rate (as previously reported in accordance with guidance prior to the adoption of the new accounting standard) for 2024 and 2023 is as follows:
 20242023
AmountTax RateAmountTax Rate
U.S. statutory rate applied to income before taxes
$4,186 21.0 %$397 21.0 %
Differential arising from:
Foreign earnings(1,301)(6.5)(941)(49.8)
Tax settlements and statute lapses
(557)(2.8)— — 
R&D tax credit(202)(1.0)(214)(11.3)
Inventory donations
(71)(0.4)(65)(3.5)
State taxes(39)(0.2)(117)(6.2)
Charges for certain research and development asset acquisitions
554 2.8 253 13.4 
Valuation allowances54 0.3 70 3.7 
Restructuring52 0.3 41 2.2 
GILTI and the foreign-derived intangible income deduction29 0.1 (80)(4.3)
Acquisition-related costs, including amortization
18 0.1 42 2.2 
Acquisition of Prometheus
— — 2,139 113.3 
Other80 0.4 (13)(0.7)
 $2,803 14.1 %$1,512 80.0 %
Where applicable, the impact of changes in uncertain tax positions is reflected in the reconciling items above.
Schedule of Income Before Taxes
Income before taxes consisted of:
Years Ended December 31202520242023
Domestic$(4,948)$(1,849)$(15,622)
Foreign26,015 21,785 17,511 
 $21,067 $19,936 $1,889 
Schedule of Taxes on Income
Taxes on income consisted of:
Years Ended December 31202520242023
Current provision
Federal$499 $944 $928 
Foreign4,072 3,123 2,435 
State(96)(15)48 
 4,475 4,052 3,411 
Deferred provision
Federal(1,585)(1,475)(1,559)
Foreign(83)212 (233)
State(3)14 (107)
 (1,671)(1,249)(1,899)
 $2,804 $2,803 $1,512 
Schedule of Deferred Income Taxes
Deferred income taxes at December 31 consisted of:
 20252024
AssetsLiabilitiesAssetsLiabilities
Product intangibles and licenses$140 $3,272 $71 $978 
R&D capitalization4,134  3,062 — 
Inventory related72 451 84 413 
Accelerated depreciation 594 — 645 
Undistributed foreign earnings
119 338 275 371 
Equity investments 155 — 90 
Pensions and other postretirement benefits117 623 224 400 
Compensation related382  400 — 
Unrecognized tax benefits160  152 — 
Net operating losses and other tax credit carryforwards1,197  910 — 
Other1,236 134 802 159 
Subtotal7,557 5,567 5,980 3,056 
Valuation allowance(824) (710) 
Total deferred taxes$6,733 $5,567 $5,270 $3,056 
Net deferred income taxes$1,166 $2,214 
Recognized as:
Other Assets$2,605 $3,601 
Deferred Income Taxes $1,439  $1,387 
Schedule of Income Taxes Paid
Income taxes paid in 2025 (presented in accordance with the new guidance) consisted of:
Year Ended December 31
2025
Domestic - federal (1)
$1,559 
Domestic - state and local
24 
Switzerland
2,115 
Netherlands
1,576 
Other foreign
812 
$6,086 
(1)    Includes TCJA transition tax payments.
Income taxes paid in 2024 and 2023 consisted of:
Years Ended December 3120242023
Domestic (1)
$974 $2,258 
Foreign2,954 2,080 
 $3,928 $4,338 
(1)    Includes TCJA transition tax payments.
Schedule of Unrecognized Tax Benefits
A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
202520242023
Balance January 1$2,261 $2,384 $1,835 
Additions related to current year positions396 421 553 
Additions related to prior year positions59 35 91 
Reductions for tax positions of prior years
(94)(33)(20)
Settlements
(28)(18)(23)
Lapse of statute of limitations (1)
(64)(528)(52)
Balance December 31$2,530 $2,261 $2,384 
(1)    Amount in 2024 reflects a reduction of $451 million resulting from the expiration of the statute of limitations related to the 2019 and 2020 federal tax return years.
v3.25.4
Earnings per Share (Tables)
12 Months Ended
Dec. 31, 2025
Earnings Per Share [Abstract]  
Schedule of Calculations of Earnings Per Share
The calculations of earnings per share (shares in millions) are as follows:
Years Ended December 31202520242023
Net Income Attributable to Merck & Co., Inc.$18,254 $17,117 $365 
Average common shares outstanding2,502 2,532 2,537 
Common shares issuable (1)
5 10 
Average common shares outstanding assuming dilution2,507 2,541 2,547 
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders$7.30 $6.76 $0.14 
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders$7.28 $6.74 $0.14 
(1)     Issuable primarily under share-based compensation plans.
v3.25.4
Other Comprehensive Income (Loss) (Tables)
12 Months Ended
Dec. 31, 2025
Equity [Abstract]  
Changes in AOCI by Component
Changes in each component of other comprehensive income (loss) are as follows:
DerivativesEmployee
Benefit
Plans
 Foreign Currency
Translation
Adjustment
Accumulated Other
Comprehensive Loss
Balance at January 1, 2023, net of taxes
$73 $(2,408)$(2,433)$(4,768)
Other comprehensive income (loss) before reclassification adjustments, pretax114 (413)17 (282)
Tax(24)86 63 125 
Other comprehensive income (loss) before reclassification adjustments, net of taxes90 (327)80 (157)
Reclassification adjustments, pretax(237)
(1)
(64)
(2)
(292)
Tax50 — 56 
Reclassification adjustments, net of taxes(187)(58)(236)
Other comprehensive income (loss), net of taxes(97)(385)89 (393)
Balance at December 31, 2023, net of taxes(24)(2,793)(2,344)(5,161)
Other comprehensive income (loss) before reclassification adjustments, pretax508 647 (559)596 
Tax(109)(138)23 (224)
Other comprehensive income (loss) before reclassification adjustments, net of taxes399 509 (536)372 
Reclassification adjustments, pretax(168)
(1)
(60)
(2)
20 (208)
Tax35 17 — 52 
Reclassification adjustments, net of taxes(133)(43)20 (156)
Other comprehensive income (loss), net of taxes266 466 (516)216 
Balance at December 31, 2024, net of taxes242 (2,327)
(3)
(2,860)(4,945)
Other comprehensive income (loss) before reclassification adjustments, pretax(577)1,101 254 778 
Tax124 (232)(77)(185)
Other comprehensive income (loss) before reclassification adjustments, net of taxes(453)869 177 593 
Reclassification adjustments, pretax134 
(1)
(53)
(2)
 81 
Tax(28)12  (16)
Reclassification adjustments, net of taxes106 (41) 65 
Other comprehensive income (loss), net of taxes(347)828 177 658 
Balance at December 31, 2025, net of taxes$(105)$(1,499)
(3)
$(2,683)$(4,287)
(1)    Primarily relates to foreign currency cash flow hedges that were reclassified from AOCL to Sales (see Note 6).
(2)    Includes net amortization of prior service cost, actuarial gains and losses, settlements and curtailments included in net periodic benefit cost (see Note 13).
(3)    Includes pension plan net loss of $2.0 billion and $3.0 billion at December 31, 2025 and 2024, respectively, and other postretirement benefit plan net gain of $365 million and $400 million at December 31, 2025 and 2024, respectively, as well as pension plan prior service credit of $146 million and $174 million at December 31, 2025 and 2024, respectively, and other postretirement benefit plan prior service credit of $29 million and $61 million at December 31, 2025 and 2024, respectively.
v3.25.4
Segment Reporting (Tables)
12 Months Ended
Dec. 31, 2025
Segment Reporting [Abstract]  
Sales of Company's Products
Sales of the Company’s products were as follows:
Years Ended December 31202520242023
U.S.Int’lTotalU.S.Int’lTotalU.S.Int’lTotal
Pharmaceutical:
Oncology
Keytruda$18,829 $12,812 $31,641 $17,872 $11,610 $29,482 $15,114 $9,897 $25,011 
Keytruda Qlex
38 2 40 — — — — — — 
Alliance revenue - Lynparza (1)
683 767 1,450 626 685 1,311 607 592 1,199 
Alliance revenue - Lenvima (1)
737 316 1,053 705 305 1,010 657 303 960 
Welireg603 113 716 466 43 509 209 10 218 
Alliance revenue - Reblozyl (2)
432 93 525 303 68 371 168 43 212 
Vaccines
Gardasil/Gardasil 9
2,641 2,592 5,233 2,425 6,158 8,583 2,083 6,803 8,886 
ProQuad/M-M-R II/Varivax1,885 566 2,451 1,919 566 2,485 1,837 531 2,368 
Vaxneuvance459 366 825 461 347 808 561 103 665 
Capvaxive
730 29 759 96 97 — — — 
RotaTeq426 246 673 472 239 711 493 276 769 
Pneumovax 23
21 146 166 56 207 263 127 285 412 
Hospital Acute Care
Bridion1,631 209 1,841 1,401 363 1,764 1,156 686 1,842 
Prevymis475 503 978 371 414 785 264 341 605 
Zerbaxa186 126 312 146 106 252 119 100 218 
Dificid202 45 247 303 37 340 274 28 302 
Cardiometabolic and Respiratory
Winrevair
1,358 85 1,443 408 11 419 — — — 
Alliance revenue - Adempas/Verquvo (3)
421 49 470 388 27 415 350 16 367 
Adempas 312 312 — 287 287 — 255 255 
Ohtuvayre
178  178 — — — — — — 
Virology
Lagevrio101 278 380 176 787 964 10 1,418 1,428 
Isentress/Isentress HD181 144 325 185 209 394 215 268 483 
Delstrigo
56 250 306 56 193 249 49 152 201 
Pifeltro
111 59 171 113 50 163 101 41 142 
Neuroscience
Belsomra82 104 186 72 150 222 81 150 231 
Immunology
Simponi   — 543 543 — 710 710 
Remicade   — 114 114 — 187 187 
Diabetes
Januvia999 605 1,604 469 865 1,334 1,151 1,039 2,189 
Janumet268 672 940 161 774 935 223 954 1,177 
Other pharmaceutical (4)
676 2,244 2,917 640 1,951 2,590 690 1,856 2,546 
Total Pharmaceutical segment sales34,409 23,733 58,142 30,290 27,110 57,400 26,539 27,044 53,583 
Animal Health:
Livestock807 3,089 3,896 732 2,729 3,462 700 2,637 3,337 
Companion Animal1,146 1,312 2,458 1,129 1,287 2,415 1,104 1,184 2,288 
Total Animal Health segment sales1,953 4,401 6,354 1,861 4,016 5,877 1,804 3,821 5,625 
Total segment sales36,362 28,134 64,496 32,151 31,126 63,277 28,343 30,865 59,208 
Other (5)
148 367 515 126 765 891 137 770 907 
 $36,510 $28,501 $65,011 $32,277 $31,891 $64,168 $28,480 $31,635 $60,115 
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 4).
(2)    Alliance revenue for Reblozyl represents royalties (see Note 4).
(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 4).
(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 $436 million, $170 million, and $97 million in 2025, 2024 and 2023, respectively (see Note 4).
(5)    Other is primarily comprised of miscellaneous corporate revenue, including revenue hedging activities which (decreased) increased sales by $(127) million, $195 million and $244 million in 2025, 2024 and 2023, respectively, as well as revenue from third-party manufacturing arrangements (including sales to Organon & Co.). Other for 2025, 2024 and 2023 also includes $138 million, $106 million and $118 million, respectively, related to upfront and milestone payments received by Merck for out-licensing arrangements.
Consolidated Revenues by Geographic Area
Consolidated sales by geographic area where derived are as follows:
Years Ended December 31202520242023
United States$36,510 $32,277 $28,480 
Europe, Middle East and Africa14,580 14,041 13,254 
Latin America3,410 3,459 3,086 
Asia Pacific (other than Japan and China)
2,983 3,058 3,225 
Japan2,711 3,280 3,164 
China1,939 5,494 6,802 
Other2,878 2,559 2,104 
 $65,011 $64,168 $60,115 
Reconciliation of Segment Profits to Income Before Taxes
A reconciliation of segment profits to Income Before Taxes is as follows:
Years Ended December 31202520242023
Pharma-ceutical
Animal Health
Total
Pharma-ceutical
Animal Health
Total
Pharma-ceutical
Animal Health
Total
Segment sales
$58,142 $6,354 $64,496 $57,400 $5,877 $63,277 $53,583 $5,625 $59,208 
Less segment costs: (1)
Cost of sales
6,679 2,649 6,828 2,469 8,849 2,498 
Selling, general and administrative
5,874 1,125 6,128 1,084 5,903 1,038 
Research and development (2)
 448 — 385 — 353 
Other segment items (3)
(165)1 (89)(49)(1)
Total segment profits45,754 2,131 47,885 44,533 1,938 46,471 38,880 1,737 40,617 
Other profits251 492 474 
Unallocated:
Interest income343 415 365 
Interest expense(1,357)(1,271)(1,146)
Amortization(2,793)(2,395)(2,044)
Depreciation(2,758)(1,843)(1,625)
Research and development(14,987)(17,350)(30,008)
Restructuring costs(889)(309)(599)
Charge for Zetia antitrust litigation settlements — (573)
Other unallocated, net(4,628)(4,274)(3,572)
$21,067 $19,936 $1,889 
(1)    The significant expense categories and amounts align with the segment level information that is regularly provided to the chief operating decision maker.
(2)    Human health-related research and development expenses incurred by Merck Research Laboratories are not allocated to segment profits as noted below.
(3)    Includes equity (income) loss from affiliates and other miscellaneous non-operating expenses.
Equity Loss from Affiliates and Depreciation Included in Segment Profits
Equity income from affiliates and depreciation included in segment profits is as follows:
PharmaceuticalAnimal HealthTotal
Year Ended December 31, 2025
Equity income from affiliates$190 $ $190 
Depreciation5 282 287 
Year Ended December 31, 2024
Equity income from affiliates$144 $— $144 
Depreciation256 261 
Year Ended December 31, 2023
Equity income from affiliates
$111 $— $111 
Depreciation198 203 
Property, Plant and Equipment, Net by Geographic Area
Property, plant and equipment, net, by geographic area where located is as follows:
December 31202520242023
United States$15,021 $14,724 $13,915 
Europe, Middle East and Africa8,856 7,548 7,562 
Asia Pacific (other than China and Japan)898 982 1,022 
China218 202 193 
Japan144 143 133 
Latin America128 133 222 
Other51 47 
 $25,316 $23,779 $23,051 
v3.25.4
Nature of Operations (Details)
12 Months Ended
Dec. 31, 2025
segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Number of operating segments 2
Number of reportable segments 2
v3.25.4
Summary of Accounting Policies (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Intangible Assets Excluding Goodwill [Line Items]      
Customer discounts $ 10,000 $ 13,300 $ 12,500
Accrual for chargebacks reflected as direct reduction to accounts receivable 295 293  
Accrual for rebates included in accrued and other current liabilities $ 1,500 2,200  
Product return period and expiration 12 months    
Depreciation $ 3,045 2,104 1,828
Advertising and promotion costs $ 2,300 $ 2,400 $ 2,300
Minimum      
Intangible Assets Excluding Goodwill [Line Items]      
Product return period 3 months    
Estimated useful life of intangible assets 2 years    
Minimum | Capitalized Software      
Intangible Assets Excluding Goodwill [Line Items]      
Estimated useful life of intangible assets 2 years    
Minimum | Buildings      
Intangible Assets Excluding Goodwill [Line Items]      
Estimated useful life of property, plant and equipment 25 years    
Minimum | Machinery, equipment and office furnishings      
Intangible Assets Excluding Goodwill [Line Items]      
Estimated useful life of property, plant and equipment 3 years    
Minimum | United States      
Intangible Assets Excluding Goodwill [Line Items]      
Payment terms, vaccine sales 30 days    
Minimum | United States | Pharmaceutical      
Intangible Assets Excluding Goodwill [Line Items]      
Payment terms 35 days    
Minimum | United States | Animal Health      
Intangible Assets Excluding Goodwill [Line Items]      
Payment terms 30 days    
Minimum | Int’l      
Intangible Assets Excluding Goodwill [Line Items]      
Payment terms 30 days    
Maximum      
Intangible Assets Excluding Goodwill [Line Items]      
Product return period 6 months    
Estimated useful life of intangible assets 24 years    
Maximum | Capitalized Software      
Intangible Assets Excluding Goodwill [Line Items]      
Estimated useful life of intangible assets 10 years    
Maximum | Buildings      
Intangible Assets Excluding Goodwill [Line Items]      
Estimated useful life of property, plant and equipment 45 years    
Maximum | Machinery, equipment and office furnishings      
Intangible Assets Excluding Goodwill [Line Items]      
Estimated useful life of property, plant and equipment 15 years    
Maximum | United States      
Intangible Assets Excluding Goodwill [Line Items]      
Payment terms 90 days    
Payment terms, vaccine sales 60 days    
Maximum | Int’l      
Intangible Assets Excluding Goodwill [Line Items]      
Payment terms 90 days    
v3.25.4
Acquisitions, Research Collaborations and Licensing Agreements - Narrative (Details)
$ in Millions
1 Months Ended 3 Months Ended 12 Months Ended 18 Months Ended
Jan. 31, 2026
USD ($)
Oct. 31, 2025
USD ($)
Mar. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Sep. 30, 2024
USD ($)
Jul. 31, 2024
USD ($)
candidate
aqua_facility
Mar. 31, 2024
USD ($)
Jun. 30, 2023
USD ($)
Jan. 31, 2023
USD ($)
Dec. 31, 2026
USD ($)
Mar. 31, 2026
USD ($)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2025
USD ($)
May 31, 2025
USD ($)
Apr. 30, 2024
candidate
Feb. 29, 2024
USD ($)
Oct. 31, 2023
USD ($)
antibodyDrugConjugate
candidate
Feb. 28, 2023
USD ($)
candidate
Business Combination [Line Items]                                        
Research and development                       $ 15,789.0 $ 17,938.0 $ 30,531.0            
Property, plant and equipment, net       $ 23,779.0               25,316.0 23,779.0 23,051.0 $ 25,316.0          
Other intangibles, net       16,370.0               26,681.0 16,370.0   26,681.0          
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                            
Dr. Falk Pharma                                        
Business Combination [Line Items]                                        
Research and development                       150.0                
Orion                                        
Business Combination [Line Items]                                        
Eligible future contingent development-related payments (up to)           $ 30.0                            
Aggregate, regulatory milestones payments, maximum           625.0                            
Sales milestone payments           $ 975.0                            
Alteogen Inc.                                        
Business Combination [Line Items]                                        
Aggregate, regulatory milestones payments, maximum                                   $ 51.0    
Sales milestone payments                                   1,000.0    
Probable contingent payments                       890.0                
Alteogen Inc. | Keytruda Qlex | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement                                        
Business Combination [Line Items]                                        
Collaborative arrangement, rights and obligations, liabilities resulting from milestone payments                       930.0     930.0     $ 40.0    
Other intangibles, net                       930.0     930.0          
Regulatory milestone payments                       40.0                
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement                                        
Business Combination [Line Items]                                        
Research and development                       524.0 351.0 5,549.0            
Number of antibody drug conjugates obtained right and obligations | antibodyDrugConjugate                                     3  
Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement                                        
Business Combination [Line Items]                                        
Eligible future contingent development-related payments (up to)                                     $ 540.0  
Aggregate, regulatory milestones payments, maximum                                     1,500.0  
Sales milestone payments                                     $ 3,100.0  
Number of antibody drug conjugates | candidate                                       7
Upfront payment made to collaborative partner                                       $ 175.0
Number of antibody drug conjugates terminated | candidate                                 1   2  
Number of exercised license option antibody drug conjugates | candidate           1                            
Number of licensed antibody drug conjugates | candidate           3                            
Number of unexercised license option antibody drug conjugates | candidate           1                            
Payment resulting from the license option exercise           $ 38.0                            
Contingent developmental milestone payments                       20.0                
Stock investment in counterparty                 $ 100.0                      
Cidara Therapeutics, Inc. | Forecast                                        
Business Combination [Line Items]                                        
Research and development                     $ 9,000.0                  
Cidara Therapeutics, Inc. | Subsequent Event                                        
Business Combination [Line Items]                                        
Consideration transferred, asset acquisition $ 9,200.0                                      
Verona Pharma plc                                        
Business Combination [Line Items]                                        
Consideration transferred, asset acquisition   $ 10,400.0                                    
Asset acquisition, intangible assets   12,100.0                                    
Cash recorded for asset acquisition   495.0                                    
Asset acquisition, inventories   522.0                                    
Fair value step up   498.0                                    
Asset acquisition, deferred tax liabilities   2,700.0                                    
Other net liabilities recorded for asset acquisition   $ 51.0                                    
Asset acquisition, finite-lived intangible asset, useful life   9 years                                    
sac-TMT | Forecast                                        
Business Combination [Line Items]                                        
Compensation earned on arrangement (up to)                   $ 700.0                    
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                                  
LM-299, LaNova Medicines Ltd                                        
Business Combination [Line Items]                                        
Consideration transferred, asset acquisition       588.0                                
Research and development                       300.0                
Future contingent developmental milestone payments (up to)       140.0                 140.0              
Future regulatory milestone payments (up to)       860.0                 860.0              
Maximum aggregate sales-based milestone payments       1,400.0                 1,400.0              
HS-10535 Hansoh Pharma                                        
Business Combination [Line Items]                                        
Consideration transferred, asset acquisition       112.0                                
Future contingent developmental milestone payments (up to)       115.0                 115.0              
Future regulatory milestone payments (up to)       315.0                 315.0              
Maximum aggregate sales-based milestone payments       $ 1,470.0                 1,470.0              
Developmental milestone payment triggered and paid                       15.0                
CN201, Curon Biopharmaceutical                                        
Business Combination [Line Items]                                        
Consideration transferred, asset acquisition         $ 700.0                              
Research and development                         750.0              
Future contingent developmental milestone payments (up to)         300.0                              
Future regulatory milestone payments (up to)         300.0                              
CN201, Curon Biopharmaceutical | Third-Party                                        
Business Combination [Line Items]                                        
Aggregate contingent developmental, regulatory, and sales-based-related payments         $ 128.0                              
Eyebiotech Limited                                        
Business Combination [Line Items]                                        
Consideration transferred, asset acquisition           1,200.0                            
Research and development                         1,350.0              
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                            
Developmental milestone payment triggered and paid                       $ 100.0 100.0   $ 200.0          
Transaction costs           207.0                            
Net assets acquired           $ 21.0                            
Harpoon Therapeutics, Inc.                                        
Business Combination [Line Items]                                        
Consideration transferred, asset acquisition             $ 765.0                          
Research and development                         $ 656.0              
Transaction costs             56.0                          
Net assets acquired             $ 165.0                          
Prometheus Biosciences, Inc.                                        
Business Combination [Line Items]                                        
Consideration transferred, asset acquisition               $ 11,000.0                        
Research and development                           10,200.0            
Cash recorded for asset acquisition               368.0                        
Other net liabilities recorded for asset acquisition               5.0                        
Net assets acquired               877.0                        
Consideration transferred, to settle share-based equity awards               1,200.0                        
Consideration transferred, to settle equity awards, unvested               700.0                        
Investments recorded for asset acquisition               296.0                        
Asset acquisition, deferred tax assets               $ 218.0                        
Imago BioSciences, Inc.                                        
Business Combination [Line Items]                                        
Consideration transferred, asset acquisition                 1,350.0                      
Research and development                           $ 1,200.0            
Transaction costs                 60.0                      
Net assets acquired                 $ 219.0                      
v3.25.4
Acquisitions, Research Collaborations and Licensing Agreements - Schedule of Estimated Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Jul. 09, 2024
Dec. 31, 2023
Business Combination [Line Items]        
Goodwill $ 21,579 $ 21,668   $ 21,197
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  
v3.25.4
Collaborative Arrangements - AstraZeneca PLC - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2028
Dec. 31, 2027
Dec. 31, 2026
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Mar. 31, 2028
Mar. 31, 2027
Feb. 28, 2026
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                  
Amortization expense for intangible assets       $ 2,800 $ 2,400 $ 2,000      
Licenses and other                  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                  
Intangible assets       3,203 3,091        
Lynparza | Licenses and other                  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                  
Intangible assets       844          
Koselugo | Licenses and other                  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                  
Intangible assets       38          
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement                  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                  
Collaborative arrangement, rights and obligations, milestone payments       700          
AstraZeneca | Alliance revenue - Koselugo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement                  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                  
Upfront payments recognized as revenue       150          
Milestone payments       175          
Sales milestone payments       235          
AstraZeneca | Alliance revenue - Koselugo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Subsequent Event                  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                  
Collaborative arrangement, future fixed upfront payments                 $ 150
AstraZeneca | Alliance revenue - Koselugo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement | Forecast                  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                  
Collaborative arrangement, future fixed upfront payments             $ 100 $ 150  
Milestone payments $ 75 $ 50 $ 50            
AstraZeneca | Lynparza | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement                  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                  
Sales milestone payments       2,000          
Collaborative arrangement, rights and obligations, milestone payments       600          
Regulatory milestone payments         245 $ 105      
AstraZeneca | Koselugo                  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                  
Amortization expense for intangible assets         48        
AstraZeneca | Koselugo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement                  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                  
Collaborative arrangement, rights and obligations, milestone payments       $ 100 $ 100        
v3.25.4
Collaborative Arrangements - AstraZeneca PLC (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Cost of sales $ 16,382 $ 15,193 $ 16,126
Selling, general and administrative 10,733 10,816 10,504
Research and development 15,789 17,938 30,531
Other current assest 43,516 38,782  
Accrued and other current liabilities 14,468 15,694  
Amortization expense for intangible assets 2,800 2,400 2,000
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Revenue from collaborative arrangement $ 1,886 $ 1,481 $ 1,296
Collaborative Arrangement, Revenue Not from Contract with Customer, Statement of Income or Comprehensive Income [Extensible Enumeration] Sales Sales Sales
Cost of sales $ 338 $ 378 $ 311
Selling, general and administrative 133 165 192
Research and development 36 77 79
Other current assest 451 424  
Other assets 125 0  
Accrued and other current liabilities 6 713  
AstraZeneca | Alliance revenue - Lynparza | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Revenue from collaborative arrangement 1,450 1,311 1,199
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 436 170 $ 97
Upfront payments recognized as revenue 150    
Milestone payments $ 175    
AstraZeneca | Koselugo      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Amortization expense for intangible assets   $ 48  
v3.25.4
Collaborative Arrangements - Eisai Co., Ltd. - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Amortization expense for intangible assets $ 2,800 $ 2,400 $ 2,000
Licenses and other      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Intangible assets 3,203 3,091  
Alliance revenue - Lenvima | Licenses and other      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Intangible assets 201    
Eisai | Alliance revenue - Lenvima      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Amortization expense for intangible assets     154
Eisai | Alliance revenue - Lenvima | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Probable contingent payments     250
Liabilities     250
Milestone payments sales-based   $ 125 $ 125
Sales milestone payments $ 2,300    
v3.25.4
Collaborative Arrangements - Eisai Co., Ltd. (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Cost of sales $ 16,382 $ 15,193 $ 16,126
Selling, general and administrative 10,733 10,816 10,504
Research and development 15,789 17,938 30,531
Other current assest 43,516 38,782  
Amortization expense for intangible assets 2,800 2,400 2,000
Eisai | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Revenue from collaborative arrangement 1,053 1,010 960
Cost of sales 241 241 381
Selling, general and administrative 134 159 189
Research and development 11 21 $ 66
Other current assest $ 271 $ 257  
v3.25.4
Collaborative Arrangements - Bayer AG (Details) - USD ($)
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Sales $ 65,011,000,000 $ 64,168,000,000 $ 60,115,000,000
Cost of sales 16,382,000,000 15,193,000,000 16,126,000,000
Selling, general and administrative 10,733,000,000 10,816,000,000 10,504,000,000
Research and development 15,789,000,000 17,938,000,000 30,531,000,000
Other current assest 43,516,000,000 38,782,000,000  
Accrued and other current liabilities 14,468,000,000 15,694,000,000  
Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Sales milestone payments 0    
Revenue from collaborative arrangement 470,000,000 415,000,000 367,000,000
Sales 830,000,000 739,000,000 658,000,000
Cost of sales 256,000,000 244,000,000 224,000,000
Selling, general and administrative 97,000,000 111,000,000 131,000,000
Research and development 56,000,000 102,000,000 90,000,000
Other current assest 167,000,000 160,000,000  
Accrued and other current liabilities 81,000,000 82,000,000  
Licenses and other      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Intangible assets 3,203,000,000 3,091,000,000  
Adempas | Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Sales 312,000,000 287,000,000 255,000,000
Adempas | Licenses and other      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Intangible assets 280,000,000    
Verquvo | Bayer AG | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Sales 48,000,000 $ 37,000,000 $ 36,000,000
Verquvo | Licenses and other      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Intangible assets $ 40,000,000    
v3.25.4
Collaborative Arrangements - Ridgeback Biotherapeutics LP (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Sales $ 65,011 $ 64,168 $ 60,115
Cost of sales 16,382 15,193 16,126
Selling, general and administrative 10,733 10,816 10,504
Research and development 15,789 17,938 30,531
Other current assest 43,516 38,782  
Accrued and other current liabilities 14,468 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 235 554 852
Selling, general and administrative 54 57 97
Research and development 31 13 60
Other current assest 27 0  
Accrued and other current liabilities 11 68  
Ridgeback Biotherapeutics LP | Lagevrio | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Sales $ 380 $ 964 $ 1,428
v3.25.4
Collaborative Arrangements - Daiicho Sankyo - Narrative (Details)
$ in Millions
1 Months Ended 12 Months Ended
Aug. 31, 2024
USD ($)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Oct. 31, 2023
USD ($)
antibodyDrugConjugate
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]          
Research and development   $ 15,789 $ 17,938 $ 30,531  
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 | antibodyDrugConjugate         3
Aggregate upfront payments due upon execution in collaborative arrangement         $ 4,000
Refundable upfront payments         1,000
Maximum aggregate contingent milestone payments, per product         $ 5,500
Research and development   $ 524 $ 351 5,549  
Royalty percentage         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         $ 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         500
Aggregate upfront payments due upon lapse of time         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         $ 750
Liable contracted portion amount of research and development expenses to incur costs for, percentage         75.00%
Liable contracted portion amount of research and development expenses to incur costs for         $ 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       $ 1,500  
v3.25.4
Collaborative Arrangements - Daiicho Sankyo (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Cost of sales $ 16,382 $ 15,193 $ 16,126
Selling, general and administrative 10,733 10,816 10,504
Research and development 15,789 17,938 30,531
Other current assest 43,516 38,782  
Accrued and other current liabilities 14,468 15,694  
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Cost of sales 66 0 0
Selling, general and administrative 28 26 3
Research and development 524 351 $ 5,549
Other current assest 15 8  
Accrued and other current liabilities $ 113 $ 817  
v3.25.4
Collaborative Arrangements - Moderna, Inc. - Narrative (Details)
$ in Millions
Dec. 31, 2025
USD ($)
Moderna | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement  
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]  
Capitalization of shared costs $ 236
v3.25.4
Collaborative Arrangements - Moderna, Inc. (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Selling, general and administrative $ 10,733 $ 10,816 $ 10,504
Research and development 15,789 17,938 30,531
Accrued and other current liabilities 14,468 15,694  
Moderna | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Selling, general and administrative 27 16 5
Research and development 375 358 $ 218
Accrued and other current liabilities $ 13 $ 57  
v3.25.4
Collaborative Arrangements - Bristol Meyers Squibb Company - Narrative (Details) - Bristol Myers Squibb Company - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Licensing Agreements      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Royalty rate, deduction, percentage 50.00%    
Licensing Agreements | Alliance revenue - Reblozyl      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Sales milestone payments $ 80    
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Revenue from collaborative arrangement $ 525 $ 371 $ 212
Minimum | Licensing Agreements      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Royalty rate, percentage 20.00%    
Maximum | Licensing Agreements      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]      
Royalty rate, percentage 24.00%    
v3.25.4
Restructuring - Narrative (Details)
$ in Millions
12 Months Ended
Dec. 31, 2025
USD ($)
site
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs $ 2,551   $ 933
2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Expected restructuring and related cost $ 3,000    
Estimate of cumulative pre tax costs that will be cash 60.00%    
Total pretax restructuring costs $ 2,012    
Number of sites | site 2    
2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Expected restructuring and related cost $ 4,000    
Total pretax restructuring costs $ 539 $ 888 $ 190
Estimate of cumulative pre tax costs that will be noncash 50.00%    
Cumulative costs since inception $ 1,600    
v3.25.4
Restructuring - Schedule of Charges Activities by Type of Cost (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs $ 2,551   $ 933
2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 2,012    
2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 539 $ 888 190
2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     743
Cost of sales | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 1,232    
Cost of sales | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 252 495 62
Cost of sales | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     149
Selling, general and administrative | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 2    
Selling, general and administrative | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 1 83  
Selling, general and administrative | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     122
Research and development | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 175    
Research and development | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs   1  
Research and development | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     1
Restructuring costs | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 603    
Restructuring costs | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 286 309 128
Restructuring costs | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     471
Accelerated Depreciation      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 1,157   140
Accelerated Depreciation | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 910    
Accelerated Depreciation | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 247 254 0
Accelerated Depreciation | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     140
Accelerated Depreciation | Cost of sales | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 910    
Accelerated Depreciation | Cost of sales | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 247 254 0
Accelerated Depreciation | Cost of sales | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     131
Accelerated Depreciation | Selling, general and administrative | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 0    
Accelerated Depreciation | Selling, general and administrative | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 0 0  
Accelerated Depreciation | Selling, general and administrative | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     9
Accelerated Depreciation | Research and development | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 0    
Accelerated Depreciation | Research and development | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs   0  
Accelerated Depreciation | Research and development | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     0
Accelerated Depreciation | Restructuring costs | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 0    
Accelerated Depreciation | Restructuring costs | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 0 0 0
Accelerated Depreciation | Restructuring costs | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     0
Separation Costs      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 609   454
Separation Costs | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 548    
Separation Costs | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 61 122 115
Separation Costs | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     339
Separation Costs | Cost of sales | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 0    
Separation Costs | Cost of sales | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 0 0 0
Separation Costs | Cost of sales | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     0
Separation Costs | Selling, general and administrative | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 0    
Separation Costs | Selling, general and administrative | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 0 0  
Separation Costs | Selling, general and administrative | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     0
Separation Costs | Research and development | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 0    
Separation Costs | Research and development | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs   0  
Separation Costs | Research and development | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     0
Separation Costs | Restructuring costs | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 548    
Separation Costs | Restructuring costs | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 61 122 115
Separation Costs | Restructuring costs | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     339
Other Exit Costs      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 785   339
Other Exit Costs | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 554    
Other Exit Costs | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 231 512 75
Other Exit Costs | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     264
Other Exit Costs | Cost of sales | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 322    
Other Exit Costs | Cost of sales | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 5 241 62
Other Exit Costs | Cost of sales | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     18
Other Exit Costs | Selling, general and administrative | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 2    
Other Exit Costs | Selling, general and administrative | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 1 83  
Other Exit Costs | Selling, general and administrative | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     113
Other Exit Costs | Research and development | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 175    
Other Exit Costs | Research and development | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs   1  
Other Exit Costs | Research and development | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     1
Other Exit Costs | Restructuring costs | 2025 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs 55    
Other Exit Costs | Restructuring costs | 2024 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs $ 225 $ 187 13
Other Exit Costs | Restructuring costs | 2019 Restructuring Program      
Restructuring Cost and Reserve [Line Items]      
Total pretax restructuring costs     $ 132
v3.25.4
Restructuring - Schedule of Activities by Program (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Restructuring Reserve [Roll Forward]      
Expenses $ 2,551   $ 933
2025 Restructuring Program      
Restructuring Reserve [Roll Forward]      
Restructuring reserve, beginning balance 0    
Expenses 2,012    
(Payments) receipts, net (96)    
Non-cash activity (1,126)    
Restructuring reserve, ending balance 790 $ 0  
2024 Restructuring Program      
Restructuring Reserve [Roll Forward]      
Restructuring reserve, beginning balance 564 712  
Expenses 539 888 190
(Payments) receipts, net (329) (445)  
Non-cash activity (268) (591)  
Restructuring reserve, ending balance 506 564 712
Accelerated Depreciation      
Restructuring Reserve [Roll Forward]      
Expenses 1,157   140
Accelerated Depreciation | 2025 Restructuring Program      
Restructuring Reserve [Roll Forward]      
Restructuring reserve, beginning balance 0    
Expenses 910    
(Payments) receipts, net 0    
Non-cash activity (910)    
Restructuring reserve, ending balance 0 0  
Accelerated Depreciation | 2024 Restructuring Program      
Restructuring Reserve [Roll Forward]      
Restructuring reserve, beginning balance 0 0  
Expenses 247 254 0
(Payments) receipts, net 0 0  
Non-cash activity (247) (254)  
Restructuring reserve, ending balance 0 0 0
Separation Costs      
Restructuring Reserve [Roll Forward]      
Expenses 609   454
Separation Costs | 2025 Restructuring Program      
Restructuring Reserve [Roll Forward]      
Restructuring reserve, beginning balance 0    
Expenses 548    
(Payments) receipts, net (46)    
Non-cash activity 0    
Restructuring reserve, ending balance 502 0  
Separation Costs | 2024 Restructuring Program      
Restructuring Reserve [Roll Forward]      
Restructuring reserve, beginning balance 564 681  
Expenses 61 122 115
(Payments) receipts, net (119) (239)  
Non-cash activity 0 0  
Restructuring reserve, ending balance 506 564 681
Other Exit Costs      
Restructuring Reserve [Roll Forward]      
Expenses 785   339
Other Exit Costs | 2025 Restructuring Program      
Restructuring Reserve [Roll Forward]      
Restructuring reserve, beginning balance 0    
Expenses 554    
(Payments) receipts, net (50)    
Non-cash activity (216)    
Restructuring reserve, ending balance 288 0  
Other Exit Costs | 2024 Restructuring Program      
Restructuring Reserve [Roll Forward]      
Restructuring reserve, beginning balance 0 31  
Expenses 231 512 75
(Payments) receipts, net (210) (206)  
Non-cash activity (21) (337)  
Restructuring reserve, ending balance $ 0 $ 0 $ 31
v3.25.4
Financial Instruments - Narrative (Details)
$ in Millions
12 Months Ended
Dec. 31, 2025
USD ($)
interest_rate_swap
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Feb. 28, 2026
USD ($)
Derivative [Line Items]        
Total Swap Notional Amount $ 40,291 $ 38,560    
Pretax net unrealized losses on derivatives maturing within the next 12 months estimated to be reclassified from AOCI to sales 178      
Equity investments without readily determinable fair values 831 863    
Unrealized gains recognized on investments in equity securities without readily determinable fair value 3 19    
Unrealized losses recognized on investments in equity securities without readily determinable fair values 70 51    
Cumulative upward price adjustment 292      
Cumulative downward price adjustment 166      
Income from investments in equity securities, net (368) (14) $ (340)  
Fair value of loans payable and long-term debt, including current portion 45,600 32,600    
Debt, carrying amount 49,300 37,100    
Factored accounts receivable 1,600 2,100    
Cash collateral received from counterparties $ 1 165    
Interest rate swap contracts        
Derivative [Line Items]        
Number of interest rate swaps held | interest_rate_swap 7      
Interest rate swap contracts | Subsequent Event        
Derivative [Line Items]        
Total Swap Notional Amount       $ 250
Equity Funds        
Derivative [Line Items]        
Equity securities held through ownership interests in investment funds $ 224 267 417  
Income from investments in equity securities, net 55 29 $ 106  
Accounts Receivable Factoring Collections        
Derivative [Line Items]        
Funds collected from factoring of receivable, held in restricted cash $ 45 55    
Customer Concentration Risk | Accounts Receivable | McKesson Corporation        
Derivative [Line Items]        
Percentage of accounts receivable represented by customers with largest balances 22.00%      
Customer Concentration Risk | Accounts Receivable | Cencora, Inc.        
Derivative [Line Items]        
Percentage of accounts receivable represented by customers with largest balances 21.00%      
Customer Concentration Risk | Accounts Receivable | Cardinal Health, Inc.        
Derivative [Line Items]        
Percentage of accounts receivable represented by customers with largest balances 13.00%      
Level 2        
Derivative [Line Items]        
Cash equivalents $ 13,800 12,300    
Derivatives Designated as Hedging Instruments        
Derivative [Line Items]        
Total Swap Notional Amount 14,712 12,465    
Derivatives Not Designated as Hedging Instruments        
Derivative [Line Items]        
Total Swap Notional Amount $ 25,579 $ 26,095    
Maximum | Derivatives Designated as Hedging Instruments        
Derivative [Line Items]        
Maximum planning cycle of hedges (less than) 2 years      
Maximum | Derivatives Not Designated as Hedging Instruments        
Derivative [Line Items]        
Maximum planning cycle of hedges (less than) 6 months      
v3.25.4
Financial Instruments - Schedule of Effect of Net Investment Hedges (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Foreign exchange contracts      
Derivative Instruments and Hedging Activities Disclosures [Line Items]      
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income $ 32 $ (30) $ 0
Foreign exchange contracts | Other (income) expense, net      
Derivative Instruments and Hedging Activities Disclosures [Line Items]      
Amount of Pretax (Gain) Loss Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing (15) (4) 1
Euro-denominated notes      
Derivative Instruments and Hedging Activities Disclosures [Line Items]      
Amount of Pretax Loss (Gain) Recognized in Other Comprehensive Income 591 (192) 105
Euro-denominated notes | Other (income) expense, net      
Derivative Instruments and Hedging Activities Disclosures [Line Items]      
Amount of Pretax (Gain) Loss Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing $ 0 $ 0 $ 0
v3.25.4
Financial Instruments - Schedule of Interest Rate Swaps Held (Details)
Feb. 28, 2026
USD ($)
Dec. 31, 2025
USD ($)
interest_rate_swap
Dec. 31, 2024
USD ($)
Derivative [Line Items]      
Total Swap Notional Amount   $ 40,291,000,000 $ 38,560,000,000
4.50% notes due 2033      
Derivative [Line Items]      
Stated interest rate   4.50%  
5.00% notes due 2053      
Derivative [Line Items]      
Stated interest rate   5.00%  
4.50% notes due 2033 | 4.50% notes due 2033      
Derivative [Line Items]      
Stated interest rate   4.50%  
5.00% notes due 2053 | 5.00% notes due 2053      
Derivative [Line Items]      
Stated interest rate   5.00%  
5.00% notes due 2053 | 5.00% notes due 2053 | Subsequent Event      
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 | Subsequent Event      
Derivative [Line Items]      
Total Swap Notional Amount $ 250,000,000    
Interest rate swap contracts | 4.50% notes due 2033      
Derivative [Line Items]      
Par Value of Debt   $ 1,500,000,000  
Number of Interest Rate Swaps Held | interest_rate_swap   6  
Total Swap Notional Amount   $ 1,500,000,000  
Interest rate swap contracts | 5.00% notes due 2053      
Derivative [Line Items]      
Par Value of Debt   $ 1,500,000,000  
Number of Interest Rate Swaps Held | interest_rate_swap   1  
Total Swap Notional Amount   $ 250,000,000  
v3.25.4
Financial Instruments - Schedule of Amounts Recorded on Balance Sheet Related to Fair Value Hedges (Details) - USD ($)
$ in Millions
Dec. 31, 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 $ 1,810 $ 1,509
Cumulative Amount of Fair Value Hedging Adjustment Increase Included in the Carrying Amount $ 70 $ 17
v3.25.4
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
Dec. 31, 2025
Dec. 31, 2024
Derivatives, Fair Value [Line Items]    
Fair value of derivative, asset $ 323 $ 729
Fair value of derivative, liability 324 345
U.S dollar notional amount 40,291 38,560
Derivatives Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Fair value of derivative, asset 216 406
Fair value of derivative, liability 132 2
U.S dollar notional amount 14,712 12,465
Derivatives Not Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Fair value of derivative, asset 107 323
Fair value of derivative, liability 192 343
U.S dollar notional amount 25,579 26,095
Interest rate swap contracts    
Derivatives, Fair Value [Line Items]    
Fair value of derivative, asset $ 71 $ 17
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 $ 71 $ 17
Derivative asset, notional amount 1,750 1,500
Foreign exchange contracts    
Derivatives, Fair Value [Line Items]    
Fair value of derivative, asset 168 499
Fair value of derivative, liability $ 293 $ 338
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 $ 113 $ 323
Derivative asset, notional amount $ 6,430 $ 8,662
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 $ 32 $ 66
Derivative asset, notional amount $ 1,793 $ 2,125
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 $ 131 $ 1
Derivative liability, notional amount $ 4,726 $ 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 $ 1 $ 1
Derivative liability, notional amount $ 13 $ 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 $ 107 $ 323
Derivative asset, notional amount $ 11,643 $ 12,544
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments | Accrued and other current liabilities    
Derivatives, Fair Value [Line Items]    
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Accrued and other current liabilities Accrued and other current liabilities
Fair value of derivative, liability $ 191 $ 343
Derivative liability, notional amount $ 13,579 $ 13,551
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments | Other Noncurrent Liabilities    
Derivatives, Fair Value [Line Items]    
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Other Noncurrent Liabilities Other Noncurrent Liabilities
Fair value of derivative, liability $ 1 $ 0
Derivative liability, notional amount $ 357 $ 0
v3.25.4
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
Dec. 31, 2025
Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Gross amounts recognized in the consolidated balance sheet, asset $ 323 $ 729
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, asset (245) (299)
Cash collateral received/posted, asset (1) (165)
Net amounts, asset 77 265
Gross amounts recognized in the consolidated balance sheet, liability 324 345
Gross amount subject to offset in master netting arrangements not offset in the condensed balance sheet, liability (245) (299)
Cash collateral received/posted, liability 0 0
Net amounts, liability $ 79 $ 46
v3.25.4
Financial Instruments - Schedule of Location and Pretax (Gains) or Loss Amounts for Derivatives (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]      
Sales $ 65,011 $ 64,168 $ 60,115
Other (income) expense, net 151 (24) 466
Other comprehensive income (loss) 658 216 (393)
Interest rate swap contracts | Other (income) expense, net      
Derivative Instruments, Gain (Loss) [Line Items]      
Hedged items 53 (39) 56
Derivatives designated as hedging instruments (54) 39 (57)
Foreign exchange contracts      
Derivative Instruments, Gain (Loss) [Line Items]      
Amount of (loss) gain recognized in OCI on derivatives (577) 508 114
(Decrease) increase in Sales as a result of AOCL reclassifications 106 (167) (249)
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 (106) 167 249
Interest rate swap contracts      
Derivative Instruments, Gain (Loss) [Line Items]      
Amount of (loss) gain recognized in OCI on derivatives 28 (1) 13
Amount of gain recognized in Other (income) expense, net on derivatives $ (1) $ (1) $ (1)
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Other (income) expense, net Other (income) expense, net Other (income) expense, net
v3.25.4
Financial Instruments - Schedule of Income Statement Effects on Derivatives Not Designated as Hedging Instruments (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Currency Swap | Other (income) expense, net      
Derivative [Line Items]      
Amount of Derivative Pretax (Gain) Loss Recognized in Income $ (196) $ 251 $ (6)
Foreign Exchange Future | Sales      
Derivative [Line Items]      
Amount of Derivative Pretax (Gain) Loss Recognized in Income $ 21 $ (28) $ 5
v3.25.4
Financial Instruments - Schedule of Information on Debt and Equity Securities (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]    
Debt securities, amortized cost $ 101 $ 536
Debt securities, gross unrealized gains 0 0
Debt securities, gross unrealized losses 0 0
Debt securities, fair value 101 536
Publicly traded equity securities 1,392 920
Total debt and publicly traded equity securities, fair value 1,493 1,456
Unrealized net gains (losses) 474 (30)
U.S. government and agency securities    
Debt Securities, Available-for-sale [Line Items]    
Debt securities, amortized cost 100 188
Debt securities, gross unrealized gains 0 0
Debt securities, gross unrealized losses 0 0
Debt securities, fair value 100 188
Foreign government bonds    
Debt Securities, Available-for-sale [Line Items]    
Debt securities, amortized cost 1 0
Debt securities, gross unrealized gains 0 0
Debt securities, gross unrealized losses 0 0
Debt securities, fair value 1 0
Commercial paper    
Debt Securities, Available-for-sale [Line Items]    
Debt securities, amortized cost 0 348
Debt securities, gross unrealized gains 0 0
Debt securities, gross unrealized losses 0 0
Debt securities, fair value $ 0 $ 348
v3.25.4
Financial Instruments - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Assets      
Commercial paper $ 101 $ 536  
Publicly traded equity securities 1,392 920  
Investments 956 910  
Other Assets 537 546  
Fair value of derivative, asset 323 729  
Total assets 1,816 2,185  
Liabilities      
Contingent consideration 0 193 $ 354
Fair value of derivative, liability 324 345  
Total liabilities 324 538  
Foreign exchange contracts      
Assets      
Fair value of derivative, asset 168 499  
Liabilities      
Fair value of derivative, liability 293 338  
Currency Options      
Assets      
Fair value of derivative, asset 84 213  
Liabilities      
Fair value of derivative, liability 31 7  
Interest rate swap contracts      
Assets      
Fair value of derivative, asset 71 17  
Foreign government bonds      
Assets      
Commercial paper 1 0  
Commercial paper      
Assets      
Commercial paper 0 348  
U.S. government and agency securities      
Assets      
Commercial paper 100 188  
U.S. government and agency securities 0 99  
Debt securities, available-for-sale 100 89  
Publicly traded equity securities      
Assets      
Publicly traded equity securities 955 463  
Publicly traded equity securities 437 457  
Level 1      
Assets      
Investments 955 463  
Other Assets 537 546  
Fair value of derivative, asset 0 0  
Total assets 1,492 1,009  
Liabilities      
Contingent consideration 0 0  
Fair value of derivative, liability 0 0  
Total liabilities 0 0  
Level 1 | Foreign exchange contracts      
Assets      
Fair value of derivative, asset 0 0  
Liabilities      
Fair value of derivative, liability 0 0  
Level 1 | Currency Options      
Assets      
Fair value of derivative, asset 0 0  
Liabilities      
Fair value of derivative, liability 0 0  
Level 1 | Interest rate swap contracts      
Assets      
Fair value of derivative, asset 0 0  
Level 1 | Foreign government bonds      
Assets      
Commercial paper 0 0  
Level 1 | Commercial paper      
Assets      
Commercial paper 0 0  
Level 1 | U.S. government and agency securities      
Assets      
U.S. government and agency securities 0 0  
Debt securities, available-for-sale 100 89  
Level 1 | Publicly traded equity securities      
Assets      
Publicly traded equity securities 955 463  
Publicly traded equity securities 437 457  
Liabilities      
Securities, fair value, which are subject to a contractual sale restriction   81  
Level 2      
Assets      
Investments 1 447  
Other Assets 0 0  
Fair value of derivative, asset 323 729  
Total assets 324 1,176  
Liabilities      
Contingent consideration 0 0  
Fair value of derivative, liability 324 345  
Total liabilities 324 345  
Level 2 | Foreign exchange contracts      
Assets      
Fair value of derivative, asset 168 499  
Liabilities      
Fair value of derivative, liability 293 338  
Level 2 | Currency Options      
Assets      
Fair value of derivative, asset 84 213  
Liabilities      
Fair value of derivative, liability 31 7  
Level 2 | Interest rate swap contracts      
Assets      
Fair value of derivative, asset 71 17  
Level 2 | Foreign government bonds      
Assets      
Commercial paper 1 0  
Level 2 | Commercial paper      
Assets      
Commercial paper 0 348  
Level 2 | U.S. government and agency securities      
Assets      
U.S. government and agency securities 0 99  
Debt securities, available-for-sale 0 0  
Level 2 | Publicly traded equity securities      
Assets      
Publicly traded equity securities 0 0  
Publicly traded equity securities 0 0  
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  
Level 3 | Foreign exchange contracts      
Assets      
Fair value of derivative, asset 0 0  
Liabilities      
Fair value of derivative, liability 0 0  
Level 3 | Currency Options      
Assets      
Fair value of derivative, asset 0 0  
Liabilities      
Fair value of derivative, liability 0 0  
Level 3 | Interest rate swap contracts      
Assets      
Fair value of derivative, asset 0 0  
Level 3 | Foreign government bonds      
Assets      
Commercial paper 0 0  
Level 3 | Commercial paper      
Assets      
Commercial paper 0 0  
Level 3 | U.S. government and agency securities      
Assets      
U.S. government and agency securities 0 0  
Debt securities, available-for-sale 0 0  
Level 3 | Publicly traded equity securities      
Assets      
Publicly traded equity securities 0 0  
Publicly traded equity securities $ 0 $ 0  
v3.25.4
Financial Instruments - Schedule of Information About Changes in Liabilities for Contingent Consideration (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 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) (10)
Payments (141) (151)
Fair value, ending balance 0 193
Zerbaxa    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Changes in estimated fair value (45)  
Payments $ (25)  
Lyfnua    
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Payments   $ (25)
v3.25.4
Inventories - Schedule of Inventories (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Inventory Disclosure [Abstract]    
Finished goods $ 2,275 $ 2,022
Raw materials and work in process 10,645 8,831
Supplies 331 289
Total 13,251 11,142
Decrease to LIFO cost (912) (840)
Total current and noncurrent inventories 12,339 10,302
Recognized as:    
Inventories 6,658 6,109
Other Assets $ 5,681 $ 4,193
v3.25.4
Inventories - Narrative (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Inventory [Line Items]    
LIFO inventory amount $ 4,300 $ 3,400
Inventory classified in other assets 5,681 4,193
Inventory Not Expected to be Sold Within One Year    
Inventory [Line Items]    
Inventory classified in other assets 5,500 3,800
Inventories Produced in Preparation for Product Launches    
Inventory [Line Items]    
Inventory classified in other assets $ 211 $ 412
v3.25.4
Goodwill and Other Intangibles - Schedule of Goodwill Activity by Segment (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Goodwill [Roll Forward]    
Goodwill, beginning balance $ 21,668 $ 21,197
Acquisitions   518
Acquisitions (106)  
Other 17 (47)
Goodwill, ending balance 21,579 21,668
Accumulated goodwill impairment losses 531 531
Pharmaceutical    
Goodwill [Roll Forward]    
Goodwill, beginning balance 17,903 17,922
Acquisitions   0
Acquisitions 0  
Other 2 (19)
Goodwill, ending balance 17,905 17,903
Animal Health    
Goodwill [Roll Forward]    
Goodwill, beginning balance 3,765 3,275
Acquisitions   518
Acquisitions (106)  
Other 15 (28)
Goodwill, ending balance $ 3,674 $ 3,765
v3.25.4
Goodwill and Other Intangibles - Schedule of Other Intangibles (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Intangible Assets Excluding Goodwill [Line Items]    
Intangible assets, gross carrying amount $ 55,410 $ 42,162
Accumulated amortization 28,729 25,792
Intangible assets, net 26,681 16,370
IPR&D    
Intangible Assets Excluding Goodwill [Line Items]    
Indefinite-lived intangible assets 427 430
Product rights    
Intangible Assets Excluding Goodwill [Line Items]    
Finite-lived intangible assets, gross carrying amount 42,038 29,988
Accumulated amortization 20,710 19,066
Finite-lived intangible assets, net 21,328 10,922
Trade names    
Intangible Assets Excluding Goodwill [Line Items]    
Finite-lived intangible assets, gross carrying amount 2,881 2,881
Accumulated amortization 1,158 954
Finite-lived intangible assets, net 1,723 1,927
Licenses and other    
Intangible Assets Excluding Goodwill [Line Items]    
Finite-lived intangible assets, gross carrying amount 10,064 8,863
Accumulated amortization 6,861 5,772
Finite-lived intangible assets, net $ 3,203 $ 3,091
v3.25.4
Goodwill and Other Intangibles - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Intangible Assets Excluding Goodwill [Line Items]      
Other intangibles, net $ 26,681 $ 16,370  
Amortization expense for intangible assets 2,800 2,400 $ 2,000
Estimated aggregate amortization expense, 2026 3,800    
Estimated aggregate amortization expense, 2027 3,600    
Estimated aggregate amortization expense, 2028 3,300    
Estimated aggregate amortization expense, 2029 3,000    
Estimated aggregate amortization expense, 2030 2,700    
IPR&D      
Intangible Assets Excluding Goodwill [Line Items]      
IPR&D intangible asset 427 430  
Animal Health      
Intangible Assets Excluding Goodwill [Line Items]      
Other intangibles, net 3,700    
Nemtabrutinib | IPR&D      
Intangible Assets Excluding Goodwill [Line Items]      
IPR&D intangible asset 418    
gefapixant | IPR&D      
Intangible Assets Excluding Goodwill [Line Items]      
IPR&D impairment charges     $ 779
Impairment, Intangible Asset, Indefinite-Lived (Excluding Goodwill), Statement of Income or Comprehensive Income [Extensible Enumeration]     Research and development
Product rights      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net 21,328 10,922  
Product rights | Ohtuvayre      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net 11,800    
Product rights | Winrevair      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net 5,400    
Product rights | Reblozyl      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net 2,500    
Product rights | Animal Health      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net 1,300    
Trade names      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net 1,723 1,927  
Trade names | Animal Health      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net 1,700    
Licensing Agreements | Keytruda Qlex      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net 886    
Licenses and other      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net 3,203 $ 3,091  
Licenses and other | Lynparza      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net 844    
Licenses and other | Lenvima      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net 201    
Licenses and other | Adempas      
Intangible Assets Excluding Goodwill [Line Items]      
Finite-lived intangible assets, net $ 280    
v3.25.4
Loans Payable, Long-Term Debt and Leases - Narrative (Details)
$ in Millions
1 Months Ended 12 Months Ended
Jan. 31, 2026
USD ($)
Oct. 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Feb. 28, 2026
USD ($)
Sep. 30, 2025
USD ($)
May 31, 2024
EUR (€)
Debt Instrument [Line Items]                
Long-term debt, current maturities     $ 2,300 $ 2,500        
Loans payable and current portion of long-term debt     2,589 $ 2,649        
Long-term debt, maturities, repayments of principal in 2026     2,600          
Long-term debt, maturities, repayments of principal in 2027     2,700          
Long-term debt, maturities, repayments of principal in 2028     2,100          
Long-term debt, maturities, repayments of principal in 2029     3,000          
Long-term debt, maturities, repayments of principal in 2030     2,700          
Long-term debt, interest payments in 2026     1,800          
Long-term debt, interest payments in 2027     1,800          
Long-term debt, interest payments in 2028     1,700          
Long-term debt, interest payments in 2029     1,600          
Long-term debt, interest payments in 2030     1,500          
Available borrowing capacity under credit facility     $ 6,000          
Operating lease, weighted average remaining lease term     7 years 6 years        
Operating lease, cost     $ 423 $ 348 $ 339      
Operating lease, payments     349 357 347      
Right-of-use asset obtained in exchange for operating lease liability     162 $ 47 $ 122      
Lessee, operating lease, lease not yet commenced, amount     $ 400          
Subsequent Event | Forecast                
Debt Instrument [Line Items]                
Lessee, operating lease, lease not yet commenced, amount           $ 300    
Lessee, operating lease, term of contract           20 years    
Cidara Therapeutics, Inc. | Subsequent Event                
Debt Instrument [Line Items]                
Consideration transferred, asset acquisition $ 9,200              
Verona Pharma plc                
Debt Instrument [Line Items]                
Consideration transferred, asset acquisition   $ 10,400            
Buildings                
Debt Instrument [Line Items]                
Operating lease, weighted average remaining lease term     7 years          
Lessee, operating lease, renewal term     5 years          
Vehicles                
Debt Instrument [Line Items]                
Operating lease, weighted average remaining lease term     4 years          
Senior Notes                
Debt Instrument [Line Items]                
Face amount of debt     $ 8,000       $ 6,000 € 3,400,000,000
Other Variable Rate Debt                
Debt Instrument [Line Items]                
Effective interest rate     4.18% 5.02%        
6.3% Debentures Due 2026                
Debt Instrument [Line Items]                
Stated interest rate     6.30%          
Floating Rate Notes Due 2029                
Debt Instrument [Line Items]                
Stated interest rate     4.35%          
Floating Rate Notes Due 2029 | Senior Notes                
Debt Instrument [Line Items]                
Face amount of debt     $ 500          
3.85% Notes Due 2029                
Debt Instrument [Line Items]                
Stated interest rate     3.85%          
3.85% Notes Due 2029 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate     3.85%          
Face amount of debt     $ 750          
4.15% Notes Due 2031                
Debt Instrument [Line Items]                
Stated interest rate     4.15%          
4.15% Notes Due 2031 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate     4.15%          
Face amount of debt     $ 1,000          
4.45% Notes Due 2032                
Debt Instrument [Line Items]                
Stated interest rate     4.45%          
4.45% Notes Due 2032 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate     4.45%       4.55%  
Face amount of debt     $ 1,000       $ 1,000  
4.75% Notes Due 2035                
Debt Instrument [Line Items]                
Stated interest rate     4.75%          
4.75% Notes Due 2035 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate     4.75%          
Face amount of debt     $ 1,500          
5.50% Notes Due 2046                
Debt Instrument [Line Items]                
Stated interest rate     5.50%          
5.50% Notes Due 2046 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate     5.50%          
Face amount of debt     $ 750          
5.55% Notes Due 2055                
Debt Instrument [Line Items]                
Stated interest rate     5.55%          
5.55% Notes Due 2055 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate     5.55%          
Face amount of debt     $ 1,500          
5.70% Notes Due 2065                
Debt Instrument [Line Items]                
Stated interest rate     5.70%          
5.70% Notes Due 2065 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate     5.70%          
Face amount of debt     $ 1,000          
Floating Rate Notes Due 2027                
Debt Instrument [Line Items]                
Stated interest rate     4.16%          
Floating Rate Notes Due 2027 | Senior Notes                
Debt Instrument [Line Items]                
Face amount of debt             $ 500  
3.85% Notes Due 2027                
Debt Instrument [Line Items]                
Stated interest rate     3.85%          
3.85% Notes Due 2027 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate             3.85%  
Face amount of debt             $ 750  
4.15% Notes Due 2030                
Debt Instrument [Line Items]                
Stated interest rate     4.15%          
4.15% Notes Due 2030 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate             4.15%  
Face amount of debt             $ 750  
4.95% Notes Due 2035                
Debt Instrument [Line Items]                
Stated interest rate     4.95%          
4.95% Notes Due 2035 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate             4.95%  
Face amount of debt             $ 1,750  
5.70% Notes Due 2055                
Debt Instrument [Line Items]                
Stated interest rate     5.70%          
5.70% Notes Due 2055 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate             5.70%  
Face amount of debt             $ 1,250  
3.25% Notes Due 2032 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate               3.25%
Face amount of debt | €               € 850,000,000
3.50% Notes Due 2037 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate               3.50%
Face amount of debt | €               € 850,000,000
3.70% Notes Due 2044 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate               3.70%
Face amount of debt | €               € 850,000,000
3.75% Notes Due 2054 | Senior Notes                
Debt Instrument [Line Items]                
Stated interest rate               3.75%
Face amount of debt | €               € 850,000,000
Repayment at Option of Holder                
Debt Instrument [Line Items]                
Loans payable and current portion of long-term debt     $ 215 $ 149        
Commercial paper                
Debt Instrument [Line Items]                
Weighted-average interest rate of commercial paper     4.32% 5.18%        
Foreign Financing Facility                
Debt Instrument [Line Items]                
Loans payable and current portion of long-term debt     $ 63          
v3.25.4
Loans Payable, Long-Term Debt and Leases - Schedule of Long-Term Debt (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Debt Instrument [Line Items]    
Long-Term Debt $ 46,750 $ 34,462
2.15% notes due 2031    
Debt Instrument [Line Items]    
Stated interest rate 2.15%  
Long-Term Debt $ 1,991 1,989
2.75% notes due 2051    
Debt Instrument [Line Items]    
Stated interest rate 2.75%  
Long-Term Debt $ 1,981 1,980
3.70% notes due 2045    
Debt Instrument [Line Items]    
Stated interest rate 3.70%  
Long-Term Debt $ 1,981 1,980
3.40% notes due 2029    
Debt Instrument [Line Items]    
Stated interest rate 3.40%  
Long-Term Debt $ 1,744 1,742
4.95% notes due 2035    
Debt Instrument [Line Items]    
Stated interest rate 4.95%  
Long-Term Debt $ 1,739 0
4.50% notes due 2033    
Debt Instrument [Line Items]    
Stated interest rate 4.50%  
Long-Term Debt $ 1,553 1,509
1.70% notes due 2027    
Debt Instrument [Line Items]    
Stated interest rate 1.70%  
Long-Term Debt $ 1,498 1,497
5.00% notes due 2053    
Debt Instrument [Line Items]    
Stated interest rate 5.00%  
Long-Term Debt $ 1,492 1,482
4.75% notes due 2035    
Debt Instrument [Line Items]    
Stated interest rate 4.75%  
Long-Term Debt $ 1,486 0
2.90% notes due 2061    
Debt Instrument [Line Items]    
Stated interest rate 2.90%  
Long-Term Debt $ 1,485 1,484
5.55% notes due 2055    
Debt Instrument [Line Items]    
Stated interest rate 5.55%  
Long-Term Debt $ 1,477 0
4.00% notes due 2049    
Debt Instrument [Line Items]    
Stated interest rate 4.00%  
Long-Term Debt $ 1,475 1,474
1.45% notes due 2030    
Debt Instrument [Line Items]    
Stated interest rate 1.45%  
Long-Term Debt $ 1,242 1,240
4.15% notes due 2043    
Debt Instrument [Line Items]    
Stated interest rate 4.15%  
Long-Term Debt $ 1,241 1,240
5.70% notes due 2055    
Debt Instrument [Line Items]    
Stated interest rate 5.70%  
Long-Term Debt $ 1,235 0
2.45% notes due 2050    
Debt Instrument [Line Items]    
Stated interest rate 2.45%  
Long-Term Debt $ 1,217 1,216
1.90% notes due 2028    
Debt Instrument [Line Items]    
Stated interest rate 1.90%  
Long-Term Debt $ 997 996
4.55% notes due 2032    
Debt Instrument [Line Items]    
Stated interest rate 4.55%  
Long-Term Debt $ 995 0
4.45% notes due 2032    
Debt Instrument [Line Items]    
Stated interest rate 4.45%  
Long-Term Debt $ 994 0
4.15% notes due 2031    
Debt Instrument [Line Items]    
Stated interest rate 4.15%  
Long-Term Debt $ 994 0
3.25% euro-denominated notes due 2032    
Debt Instrument [Line Items]    
Stated interest rate 3.25%  
Long-Term Debt $ 993 880
3.50% euro-denominated notes due 2037    
Debt Instrument [Line Items]    
Stated interest rate 3.50%  
Long-Term Debt $ 990 877
5.15% notes due 2063    
Debt Instrument [Line Items]    
Stated interest rate 5.15%  
Long-Term Debt $ 988 987
3.90% notes due 2039    
Debt Instrument [Line Items]    
Stated interest rate 3.90%  
Long-Term Debt $ 988 987
3.70% euro-denominated notes due 2044    
Debt Instrument [Line Items]    
Stated interest rate 3.70%  
Long-Term Debt $ 988 876
2.35% notes due 2040    
Debt Instrument [Line Items]    
Stated interest rate 2.35%  
Long-Term Debt $ 987 986
3.75% euro-denominated notes due 2054    
Debt Instrument [Line Items]    
Stated interest rate 3.75%  
Long-Term Debt $ 985 873
5.70% notes due 2065    
Debt Instrument [Line Items]    
Stated interest rate 5.70%  
Long-Term Debt $ 984 0
4.30% notes due 2030    
Debt Instrument [Line Items]    
Stated interest rate 4.30%  
Long-Term Debt $ 747 746
3.85% notes due 2027    
Debt Instrument [Line Items]    
Stated interest rate 3.85%  
Long-Term Debt $ 747 0
3.85% notes due 2029    
Debt Instrument [Line Items]    
Stated interest rate 3.85%  
Long-Term Debt $ 746 0
4.15% notes due 2030    
Debt Instrument [Line Items]    
Stated interest rate 4.15%  
Long-Term Debt $ 745 0
5.50% notes due 2046    
Debt Instrument [Line Items]    
Stated interest rate 5.50%  
Long-Term Debt $ 742 0
4.90% notes due 2044    
Debt Instrument [Line Items]    
Stated interest rate 4.90%  
Long-Term Debt $ 740 740
6.50% notes due 2033    
Debt Instrument [Line Items]    
Stated interest rate 6.50%  
Long-Term Debt $ 698 702
1.375% euro-denominated notes due 2036    
Debt Instrument [Line Items]    
Stated interest rate 1.375%  
Long-Term Debt $ 583 517
2.50% euro-denominated notes due 2034    
Debt Instrument [Line Items]    
Stated interest rate 2.50%  
Long-Term Debt $ 583 517
4.05% notes due 2028    
Debt Instrument [Line Items]    
Stated interest rate 4.05%  
Long-Term Debt $ 499 498
Floating rate notes due 2027    
Debt Instrument [Line Items]    
Stated interest rate 4.16%  
Long-Term Debt $ 499 0
Basis spread on variable rate 0.46%  
Floating rate notes due 2029    
Debt Instrument [Line Items]    
Stated interest rate 4.35%  
Long-Term Debt $ 498 0
Basis spread on variable rate 0.57%  
3.60% notes due 2042    
Debt Instrument [Line Items]    
Stated interest rate 3.60%  
Long-Term Debt $ 493 492
6.55% notes due 2037    
Debt Instrument [Line Items]    
Stated interest rate 6.55%  
Long-Term Debt $ 402 404
5.75% notes due 2036    
Debt Instrument [Line Items]    
Stated interest rate 5.75%  
Long-Term Debt $ 339 339
5.95% debentures due 2028    
Debt Instrument [Line Items]    
Stated interest rate 5.95%  
Long-Term Debt $ 308 307
5.85% notes due 2039    
Debt Instrument [Line Items]    
Stated interest rate 5.85%  
Long-Term Debt $ 271 271
6.40% debentures due 2028    
Debt Instrument [Line Items]    
Stated interest rate 6.40%  
Long-Term Debt $ 251 251
1.875% euro-denominated notes due 2026    
Debt Instrument [Line Items]    
Stated interest rate 1.875%  
Long-Term Debt $ 0 1,041
0.75% notes due 2026    
Debt Instrument [Line Items]    
Stated interest rate 0.75%  
Long-Term Debt $ 0 998
6.30% debentures due 2026    
Debt Instrument [Line Items]    
Stated interest rate 6.30%  
Long-Term Debt $ 0 135
Other    
Debt Instrument [Line Items]    
Long-Term Debt $ 139 $ 209
v3.25.4
Loans Payable, Long-Term Debt and Leases - Schedule of Balance Sheet Information (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Debt Disclosure [Abstract]    
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Other Assets Other Assets
Other Assets $ 1,507 $ 1,370
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Accrued and other current liabilities Accrued and other current liabilities
Accrued and other current liabilities $ 294 $ 282
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Other Noncurrent Liabilities Other Noncurrent Liabilities
Other Noncurrent Liabilities $ 901 $ 877
Total operating lease liability $ 1,195 $ 1,159
Weighted-average remaining lease term (years) 7 years 6 years
Weighted-average discount rate 3.50% 3.20%
v3.25.4
Loans Payable, Long-Term Debt and Leases - Schedule of Maturity Schedule (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Debt Disclosure [Abstract]    
2026 $ 335  
2027 261  
2028 204  
2029 125  
2030 103  
Thereafter 415  
Total lease payments 1,443  
Less: Imputed interest 248  
Total operating lease liability $ 1,195 $ 1,159
v3.25.4
Contingencies and Environmental Liabilities (Details)
$ in Millions
1 Months Ended 2 Months Ended 5 Months Ended 6 Months Ended 12 Months Ended
Mar. 13, 2025
Dec. 19, 2022
Apr. 30, 2025
patent
Aug. 31, 2024
case
Dec. 31, 2023
case
Jun. 30, 2023
May 31, 2023
patent
Oct. 31, 2024
patent
Nov. 30, 2025
patent
Dec. 31, 2025
USD ($)
case
company
Sep. 19, 2025
Jun. 30, 2025
patent
Mar. 11, 2025
case
Dec. 31, 2024
USD ($)
Loss Contingencies [Line Items]                            
Loss contingency, joint stipulation response period                     15 days      
Environmental Loss Contingency Statement Of Financial Position Extensible Enumeration Not Disclosed Flag                   liabilities        
Accrued liabilities for environmental matters | $                   $ 42       $ 41
Term for paying off environmental liabilities                   15 years        
Aggregate possible expenditure on environmental matters in excess of amounts accrued | $                   $ 58        
Legal Defense Costs                            
Loss Contingencies [Line Items]                            
Legal defense costs reserve | $                   $ 245       $ 225
Pending Litigation | Patents - PGR Petition                            
Loss Contingencies [Line Items]                            
Number of patents allegedly infringed     12                      
Dr. Scholl's | United States | Pending Litigation                            
Loss Contingencies [Line Items]                            
Loss contingency, pending claims | case                   610        
Gardasil/Gardasil 9 | United States | Pending Litigation                            
Loss Contingencies [Line Items]                            
Loss contingency, pending claims | case                   135        
Gardasil/Gardasil 9 | United States | Motion for Summary Judgement Granted                            
Loss Contingencies [Line Items]                            
Loss contingency, pending claims | case                         16  
Gardasil/Gardasil 9 | Int’l | Pending Litigation                            
Loss Contingencies [Line Items]                            
Loss contingency, pending claims | case                   15        
Zetia | United States | Pending Litigation                            
Loss Contingencies [Line Items]                            
Loss contingency, number of cases remanded | case         4                  
Bravecto | United States                            
Loss Contingencies [Line Items]                            
Loss contingency, number of statewide classes for certification | case       5                    
Bridion | Patents                            
Loss Contingencies [Line Items]                            
Loss contingency, claims settled, number of companies | company                   5        
Bridion | Pending Litigation | Patents                            
Loss Contingencies [Line Items]                            
Loss contingency, trial period   1 day                        
Bridion | Settled Litigation | Patents                            
Loss Contingencies [Line Items]                            
Patent extension, term 5 years         5 years                
Pediatric exclusivity, term 6 months                          
Januvia, Janumet, Janumet XR | Settled Litigation                            
Loss Contingencies [Line Items]                            
Loss contingency, companies settled with, minimum number | company                   24        
Keytruda | Pending Litigation | Patents                            
Loss Contingencies [Line Items]                            
Number of patents allegedly infringed             9 9            
Number of additional patents unpatentable                 9          
Subcutaneous Pembrolizumab | Pending Litigation | Patents                            
Loss Contingencies [Line Items]                            
Loss contingency, pending claims                       1    
Number of patents allegedly infringed     15                      
Subcutaneous Pembrolizumab | Pending Litigation | Patents - PGR Petition                            
Loss Contingencies [Line Items]                            
Loss contingency, pending claims                       13    
Subcutaneous Pembrolizumab | Pending Litigation | PGR Petition Process, Ineligible to be Challenged                            
Loss Contingencies [Line Items]                            
Loss contingency, pending claims     3                      
v3.25.4
Equity - Narrative (Details) - shares
Dec. 31, 2025
Dec. 31, 2024
Equity [Abstract]    
Common stock, authorized (in shares) 6,500,000,000 6,500,000,000
Preferred stock, authorized (in shares) 20,000,000  
v3.25.4
Equity - Schedule of Shareholders' Equity (Details) - shares
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Movement in Common Stock and Treasury Stock [Roll Forward]      
Balance January 1, common stock (in shares) 3,577,103,522    
Balance January 1, treasury stock (in shares) 1,049,466,187    
Balance December 31, common stock (in shares) 3,577,103,522 3,577,103,522  
Balance December 31, treasury stock (in shares) 1,102,476,756 1,049,466,187  
Common Stock      
Movement in Common Stock and Treasury Stock [Roll Forward]      
Balance January 1, common stock (in shares) 3,577,000,000 3,577,000,000 3,577,000,000
Balance December 31, common stock (in shares) 3,577,000,000 3,577,000,000 3,577,000,000
Treasury Stock      
Movement in Common Stock and Treasury Stock [Roll Forward]      
Balance January 1, treasury stock (in shares) 1,049,000,000 1,045,000,000 1,039,000,000
Purchases of treasury stock (in shares) 59,000,000 11,000,000 13,000,000
Issuances (in shares) (6,000,000) (7,000,000) (7,000,000)
Balance December 31, treasury stock (in shares) 1,102,000,000 1,049,000,000 1,045,000,000
v3.25.4
Share-Based Compensation Plans - Narrative (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares collectively authorized for future grants under share-based compensation plans (in shares) 66,000,000    
Pretax share-based compensation cost recorded, related to continuing operations $ 820 $ 761 $ 645
Income tax benefits related to share-based compensation $ 125 $ 117 $ 96
Weighted average exercise price of options granted (in dollars per share) $ 84.71 $ 129.22 $ 117.89
Total pre tax unrecognized compensation expense related to nonvested stock options, RSU and PSU awards $ 1,100    
Weighted average period in years of recognition for nonvested stock options, RSU and PSU awards 1 year 10 months 24 days    
Employee Stock Option      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Quantity of stock options that vest per year 33.33%    
Period over which share-based payment awards vest 3 years    
PSUs      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Period over which share-based payment awards vest 3 years    
RSUs      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Quantity of stock options that vest per year 33.33%    
Period over which share-based payment awards vest 3 years    
Minimum | Employee Stock Option      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Contractual term of options 7 years    
Maximum | Employee Stock Option      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Contractual term of options 10 years    
v3.25.4
Share-Based Compensation Plans - Schedule of Assumptions Used to Determine Weighted-Average Fair Value of Options Granted (Details) - $ / shares
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]      
Weighted average fair value of options granted (in dollars per share) $ 18.61 $ 25.60 $ 21.69
Expected dividend yield 3.10% 3.00% 3.10%
Risk-free interest rate 3.90% 4.70% 3.40%
Expected volatility 25.90% 20.50% 22.40%
Expected life (years) 5 years 9 months 18 days 5 years 9 months 18 days 5 years 9 months 18 days
v3.25.4
Share-Based Compensation Plans - Schedule of Information Relative to Stock Option Plan Activity (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Number of Options      
Number of Options, Outstanding, January 1 (in shares) 12,500    
Number of Options, Granted (in shares) 1,616    
Number of Options, Exercised (in shares) (1,428)    
Number of Options, Forfeited (in shares) (211)    
Number of Options, Outstanding, December 31 (in shares) 12,477 12,500  
Number of Options, Vested and expected to vest (in shares) 12,235    
Number of Options, Exercisable (in shares) 9,348    
Weighted Average Exercise Price      
Weighted Average Exercise Price, Options Outstanding, January 1 (in dollars per share) $ 86.04    
Weighted Average Exercise Price, Granted (in dollars per share) 84.71 $ 129.22 $ 117.89
Weighted Average Exercise Price, Exercised (in dollars per share) 64.76    
Weighted Average Exercise Price, Forfeited (in dollars per share) 106.46    
Weighted Average Exercise Price, Options Outstanding, December 31 (in dollars per share) 87.95 $ 86.04  
Weighted Average Exercise Price, Vested and expected to vest (in dollars per share) 87.73    
Weighted Average Exercise Price, Exercisable (in dollars per share) $ 82.09    
Weighted Average Remaining Contractual Term, Outstanding 5 years 8 months 12 days    
Weighted Average Remaining Contractual Term, Vested and expected to vest 5 years 8 months 12 days    
Weighted Average Remaining Contractual Term, Exercisable 4 years 9 months 18 days    
Aggregate Intrinsic Value, Outstanding $ 275    
Aggregate Intrinsic Value, Vested and expected to vest 272    
Aggregate Intrinsic Value, Exercisable $ 244    
v3.25.4
Share-Based Compensation Plans - Schedule of Additional Information Pertaining to Stock Option Plans (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]      
Total intrinsic value of stock options exercised $ 41 $ 144 $ 95
Fair value of stock options vested 36 32 30
Cash received from the exercise of stock options $ 92 $ 177 $ 125
v3.25.4
Share-Based Compensation Plans - Schedule of Nonvested RSU and PSU Activity (Details)
shares in Thousands
12 Months Ended
Dec. 31, 2025
$ / shares
shares
RSUs  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]  
Number of Shares, Nonvested January 1 (in shares) | shares 12,232
Number of Shares, Granted (in shares) | shares 10,318
Number of Shares, Vested (in shares) | shares (6,042)
Number of Shares, Forfeited (in shares) | shares (786)
Number of Shares, Nonvested December 31 (in shares) | shares 15,722
Number of Shares, Expected to Vest (in shares) | shares 13,978
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]  
Weighted Average Grant Date Fair Value, Nonvested January 1 (in dollars per share) | $ / shares $ 117.94
Weighted Average Grant Date Fair Value, Granted (in dollars per share) | $ / shares 84.65
Weighted Average Grant Date Fair Value, Vested (in dollars per share) | $ / shares 110.84
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share) | $ / shares 104.44
Weighted Average Grant Date Fair Value, Nonvested December 31 (in dollars per share) | $ / shares 99.50
Weighted Average Grant Date Fair Value, Expected to vest (in dollars per share) | $ / shares $ 100.27
PSUs  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]  
Number of Shares, Nonvested January 1 (in shares) | shares 1,766
Number of Shares, Granted (in shares) | shares 1,233
Number of Shares, Vested (in shares) | shares (1,101)
Number of Shares, Forfeited (in shares) | shares (64)
Number of Shares, Nonvested December 31 (in shares) | shares 1,834
Number of Shares, Expected to Vest (in shares) | shares 1,732
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]  
Weighted Average Grant Date Fair Value, Nonvested January 1 (in dollars per share) | $ / shares $ 117.57
Weighted Average Grant Date Fair Value, Granted (in dollars per share) | $ / shares 81.20
Weighted Average Grant Date Fair Value, Vested (in dollars per share) | $ / shares 88.42
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share) | $ / shares 104.87
Weighted Average Grant Date Fair Value, Nonvested December 31 (in dollars per share) | $ / shares 111.13
Weighted Average Grant Date Fair Value, Expected to vest (in dollars per share) | $ / shares $ 111.82
v3.25.4
Pension and Other Postretirement Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Other Postretirement Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Service cost $ 37 $ 30 $ 32
Interest cost 61 56 63
Expected return on plan assets (50) (80) (64)
Amortization of unrecognized prior service (credit) cost (40) (43) (49)
Net loss (gain) amortization (45) (51) (42)
Termination benefits 0 4 0
Curtailments (3) 0 (1)
Settlements 0 0 0
Net periodic benefit cost (credit) (40) (84) (61)
United States | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 378 373 326
Interest cost 569 537 526
Expected return on plan assets (840) (826) (735)
Amortization of unrecognized prior service (credit) cost 0 0 (1)
Net loss (gain) amortization 58 43 0
Termination benefits 2 5 3
Curtailments 9 0 8
Settlements 0 0 28
Net periodic benefit cost (credit) 176 132 155
International | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 228 243 196
Interest cost 303 294 299
Expected return on plan assets (613) (554) (517)
Amortization of unrecognized prior service (credit) cost (28) (13) 2
Net loss (gain) amortization 11 5 (3)
Termination benefits 0 1 0
Curtailments (15) 0 (1)
Settlements 0 (1) (5)
Net periodic benefit cost (credit) $ (114) $ (25) $ (29)
v3.25.4
Pension and Other Postretirement Benefit Plans - Obligation and Funded Status (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Other Postretirement Benefits      
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]      
Fair value of plan assets January 1 $ 1,040 $ 1,045  
Actual return on plan assets 86 35  
Company contributions 71 46  
Effects of exchange rate changes 0 0  
Benefits paid (90) (89)  
Settlements 0 0  
Other 0 3  
Fair value of plan assets December 31 1,107 1,040 $ 1,045
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]      
Benefit obligation January 1 1,136 1,104  
Service cost 37 30 32
Interest cost 61 56 63
Actuarial losses (gains) 34 32  
Benefits paid (90) (89)  
Effects of exchange rate changes 3 (4)  
Plan amendments 0 0  
Curtailments (2) 0  
Termination benefits 0 4 0
Settlements 0 0  
Other 0 3  
Benefit obligation December 31 1,179 1,136 1,104
Funded status December 31 (72) (96)  
Recognized as:      
Other Assets 66 51  
Accrued and other current liabilities (7) (7)  
Other Noncurrent Liabilities (131) (140)  
United States | Pension Benefits      
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]      
Fair value of plan assets January 1 9,717 9,804  
Actual return on plan assets 1,435 266  
Company contributions 267 262  
Effects of exchange rate changes 0 0  
Benefits paid (689) (615)  
Settlements 0 0  
Other 0 0  
Fair value of plan assets December 31 10,730 9,717 9,804
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]      
Benefit obligation January 1 10,151 10,446  
Service cost 378 373 326
Interest cost 569 537 526
Actuarial losses (gains) 178 (595)  
Benefits paid (689) (615)  
Effects of exchange rate changes 0 0  
Plan amendments 0 0  
Curtailments 9 0  
Termination benefits 2 5 3
Settlements 0 0  
Other 0 0  
Benefit obligation December 31 10,598 10,151 10,446
Funded status December 31 132 (434)  
Recognized as:      
Other Assets 602 26  
Accrued and other current liabilities (58) (55)  
Other Noncurrent Liabilities (412) (405)  
International | Pension Benefits      
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]      
Fair value of plan assets January 1 9,647 9,562  
Actual return on plan assets 318 637  
Company contributions 195 198  
Effects of exchange rate changes 1,010 (522)  
Benefits paid (268) (250)  
Settlements (38) (14)  
Other 42 36  
Fair value of plan assets December 31 10,906 9,647 9,562
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]      
Benefit obligation January 1 8,274 9,042  
Service cost 228 243 196
Interest cost 303 294 299
Actuarial losses (gains) (962) (549)  
Benefits paid (268) (250)  
Effects of exchange rate changes 879 (473)  
Plan amendments (5) (56)  
Curtailments (4) 0  
Termination benefits 0 1 0
Settlements (38) (14)  
Other 45 36  
Benefit obligation December 31 8,452 8,274 $ 9,042
Funded status December 31 2,454 1,373  
Recognized as:      
Other Assets 2,770 1,785  
Accrued and other current liabilities (20) (18)  
Other Noncurrent Liabilities $ (296) $ (394)  
v3.25.4
Pension and Other Postretirement Benefit Plans - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2026
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]        
Employer contributions to defined contribution savings plans   $ 223 $ 215 $ 199
Pension Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Accumulated benefit obligation   $ 18,700 $ 18,100  
Percentage of Company's pension investments categorized as level 3 assets   3.00% 4.00%  
Pension Benefits | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets   $ 737 $ 700  
Other Postretirement Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets   1,107 1,040 $ 1,045
Expected contributions to the pension plans and other postretirement benefit plans during next fiscal year   70    
Other Postretirement Benefits | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets   $ 0 $ 0  
United States        
Defined Benefit Plan Disclosure [Line Items]        
Expected annual standard deviation in returns of the target portfolio which reflects both the equity allocation and the diversification benefits among the asset classes in which the portfolio invests   11.00%    
Expected rate of return on plan assets   7.70% 7.75% 7.00%
United States | Forecast | Subsequent Event        
Defined Benefit Plan Disclosure [Line Items]        
Expected rate of return on plan assets 7.70%      
United States | U.S. equities | Minimum        
Defined Benefit Plan Disclosure [Line Items]        
Target allocation   25.00%    
United States | U.S. equities | Maximum        
Defined Benefit Plan Disclosure [Line Items]        
Target allocation   40.00%    
United States | International equities | Minimum        
Defined Benefit Plan Disclosure [Line Items]        
Target allocation   15.00%    
United States | International equities | Maximum        
Defined Benefit Plan Disclosure [Line Items]        
Target allocation   30.00%    
United States | Fixed Income Investments | Minimum        
Defined Benefit Plan Disclosure [Line Items]        
Target allocation   40.00%    
United States | Fixed Income Investments | Maximum        
Defined Benefit Plan Disclosure [Line Items]        
Target allocation   50.00%    
United States | Cash And Other Investments | Maximum        
Defined Benefit Plan Disclosure [Line Items]        
Target allocation   8.00%    
United States | Pension Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Accumulated benefit obligation   $ 10,400 $ 10,000  
Fair value of plan assets   10,730 9,717 $ 9,804
Expected contributions to the pension plans and other postretirement benefit plans during next fiscal year   270    
United States | Pension Benefits | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets   2 2 3
International | Pension Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets   10,906 $ 9,647 $ 9,562
Expected contributions to the pension plans and other postretirement benefit plans during next fiscal year   $ 190    
Expected rate of return on plan assets   5.40% 5.20% 5.00%
International | Pension Benefits | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets   $ 735 $ 698 $ 785
v3.25.4
Pension and Other Postretirement Benefit Plans - Accumulated and Projected Benefit Obligation in Excess of Plan Assets (Details) - Pension Benefits - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
United States    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Pension plans with a projected benefit obligation in excess of plan assets, projected benefit obligation $ 469 $ 9,517
Pension plans with a projected benefit obligation in excess of plan assets, fair value of plan assets 0 9,057
Pension plans with an accumulated benefit obligation in excess of plan assets, accumulated benefit obligation 449 442
Pension plans with an accumulated benefit obligation in excess of plan assets, fair value of plan assets 0 0
International    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Pension plans with a projected benefit obligation in excess of plan assets, projected benefit obligation 1,405 1,847
Pension plans with a projected benefit obligation in excess of plan assets, fair value of plan assets 1,089 1,435
Pension plans with an accumulated benefit obligation in excess of plan assets, accumulated benefit obligation 1,332 1,768
Pension plans with an accumulated benefit obligation in excess of plan assets, fair value of plan assets $ 1,038 $ 1,385
v3.25.4
Pension and Other Postretirement Benefit Plans - Fair Values of Pension Plan Assets (Details) - Pension Benefits - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 737 $ 700  
United States      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 10,730 9,717 $ 9,804
United States | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 342 164  
United States | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 3,474 2,555  
United States | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 905 1,265  
United States | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 298 174  
United States | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2,109 2,171  
United States | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2,206 2,101  
United States | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1,397 1,293  
United States | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 18 21  
United States | Derivatives      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets (21) (29)  
United States | Other      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2 2  
United States | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2,484 2,355  
United States | Level 1 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 200 43  
United States | Level 1 | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 196 170  
United States | Level 1 | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 1 | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 1 | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2,109 2,171  
United States | Level 1 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 1 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 1 | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 1 | Derivatives      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets (21) (29)  
United States | Level 1 | Other      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 3,621 3,415  
United States | Level 2 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 2 | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 2 | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 2 | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 2 | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 2 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2,206 2,101  
United States | Level 2 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1,397 1,293  
United States | Level 2 | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 18 21  
United States | Level 2 | Derivatives      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 2 | Other      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2 2 3
United States | Level 3 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 3 | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 3 | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 3 | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 3 | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 3 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 3 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 3 | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 3 | Derivatives      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | Level 3 | Other      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2 2 3
United States | Level 3 | Insurance contracts      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0 0
United States | NAV      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4,623 3,945  
United States | NAV | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 142 121  
United States | NAV | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 3,278 2,385  
United States | NAV | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 905 1,265  
United States | NAV | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 298 174  
United States | NAV | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | NAV | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | NAV | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | NAV | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | NAV | Derivatives      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
United States | NAV | Other      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 10,906 9,647 9,562
International | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 106 123  
International | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4,974 4,232  
International | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 161 145  
International | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 17 12  
International | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 3,786 3,385  
International | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 191 180  
International | Other fixed income obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 36 19  
International | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 289 287  
International | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 413 368  
International | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 147 141  
International | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 51 54  
International | Insurance contracts      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 735 701  
International | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 1,640 1,345  
International | Level 1 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 90 112  
International | Level 1 | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 815 599  
International | Level 1 | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 71 54  
International | Level 1 | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 1 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 323 262  
International | Level 1 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 25 23  
International | Level 1 | Other fixed income obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 27 8  
International | Level 1 | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 289 287  
International | Level 1 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 1 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 1 | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 1 | Insurance contracts      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 7,961 7,090  
International | Level 2 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 5 0  
International | Level 2 | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4,024 3,537  
International | Level 2 | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 2 | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 2 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 3,306 2,974  
International | Level 2 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 10 8  
International | Level 2 | Other fixed income obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 5 7  
International | Level 2 | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 2 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 413 368  
International | Level 2 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 147 141  
International | Level 2 | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 51 54  
International | Level 2 | Insurance contracts      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 1  
International | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 735 698 785
International | Level 3 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 3 | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 3 | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 3 | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 3 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 3 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 3 | Other fixed income obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 3 | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 3 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 3 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 3 | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | Level 3 | Other      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0 0
International | Level 3 | Insurance contracts      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 735 698 $ 785
International | NAV      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 570 514  
International | NAV | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 11 11  
International | NAV | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 135 96  
International | NAV | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 90 91  
International | NAV | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 17 12  
International | NAV | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 157 149  
International | NAV | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 156 149  
International | NAV | Other fixed income obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4 4  
International | NAV | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | NAV | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | NAV | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | NAV | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 0 0  
International | NAV | Insurance contracts      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 0 $ 2  
v3.25.4
Pension and Other Postretirement Benefit Plans - Summary of Changes in Fair Value of Company's Level 3 Pension Plan Assets (Details) - Pension Benefits - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Level 3    
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 $ 700  
Actual return on plan assets:    
Fair value of plan assets December 31 737 $ 700
United States    
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 9,717 9,804
Actual return on plan assets:    
Fair value of plan assets December 31 10,730 9,717
United States | Other    
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 2  
Actual return on plan assets:    
Fair value of plan assets December 31 2 2
United States | Level 3    
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 2 3
Actual return on plan assets:    
Relating to assets still held at December 31 0 (2)
Relating to assets sold during the year 0 2
Purchases and sales, net 0 (1)
Fair value of plan assets December 31 2 2
United States | Level 3 | Insurance Contracts    
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 0 0
Actual return on plan assets:    
Relating to assets still held at December 31 0 0
Relating to assets sold during the year 0 0
Purchases and sales, net 0 0
Fair value of plan assets December 31 0 0
United States | Level 3 | Other    
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 2 3
Actual return on plan assets:    
Relating to assets still held at December 31 0 (2)
Relating to assets sold during the year 0 2
Purchases and sales, net 0 (1)
Fair value of plan assets December 31 2 2
International    
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 9,647 9,562
Actual return on plan assets:    
Fair value of plan assets December 31 10,906 9,647
International | Insurance Contracts    
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 701  
Actual return on plan assets:    
Fair value of plan assets December 31 735 701
International | Level 3    
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 698 785
Actual return on plan assets:    
Relating to assets still held at December 31 117 (26)
Purchases and sales, net (85) (61)
Transfers into Level 3 5 0
Fair value of plan assets December 31 735 698
International | Level 3 | Insurance Contracts    
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 698 785
Actual return on plan assets:    
Relating to assets still held at December 31 117 (26)
Purchases and sales, net (85) (61)
Transfers into Level 3 5 0
Fair value of plan assets December 31 735 698
International | Level 3 | Other    
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]    
Fair value of plan assets January 1 0 0
Actual return on plan assets:    
Relating to assets still held at December 31 0 0
Purchases and sales, net 0 0
Transfers into Level 3 0 0
Fair value of plan assets December 31 $ 0 $ 0
v3.25.4
Pension and Other Postretirement Benefit Plans - Fair Values of Other Postretirement Benefit Plan Assets (Details) - Other Postretirement Benefits - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value $ 1,107 $ 1,040 $ 1,045
Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 18 5  
Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 61 49  
Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 16 24  
Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 5 3  
Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 38 41  
Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 645 598  
Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 261 266  
Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 63 54  
Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 55 44  
Level 1 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 14 0  
Level 1 | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 3 3  
Level 1 | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 1 | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 1 | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 38 41  
Level 1 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 1 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 1 | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 969 918  
Level 2 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 2 | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 2 | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 2 | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 2 | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 2 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 645 598  
Level 2 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 261 266  
Level 2 | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 63 54  
Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 3 | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 3 | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 3 | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 3 | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 3 | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 3 | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 3 | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
Level 3 | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
NAV      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 83 78  
NAV | Cash and cash equivalents      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 4 5  
NAV | Developed markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 58 46  
NAV | Emerging markets equities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 16 24  
NAV | Real estate      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 5 3  
NAV | Developed markets      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
NAV | Corporate obligations      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
NAV | Government and agency obligations      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value 0 0  
NAV | Mortgage and asset-backed securities      
Defined Benefit Plan Disclosure [Line Items]      
Plan assets at fair value $ 0 $ 0  
v3.25.4
Pension and Other Postretirement Benefit Plans - Summary of Expected Benefit Payments (Details)
$ in Millions
Dec. 31, 2025
USD ($)
Other Postretirement Benefits  
Defined Benefit Plan Disclosure [Line Items]  
2026 $ 88
2027 90
2028 94
2029 98
2030 102
2031 — 2035 554
United States | Pension Benefits  
Defined Benefit Plan Disclosure [Line Items]  
2026 834
2027 832
2028 833
2029 847
2030 866
2031 — 2035 4,531
International | Pension Benefits  
Defined Benefit Plan Disclosure [Line Items]  
2026 334
2027 323
2028 336
2029 354
2030 362
2031 — 2035 $ 2,108
v3.25.4
Pension and Other Postretirement Benefit Plans - Components of Other Comprehensive Income (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Other Postretirement Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Net gain (loss) arising during the period $ 2 $ (78) $ 110
Prior service credit (cost) arising during the period 0 0 0
Total 2 (78) 110
Net loss (gain) amortization included in benefit cost (45) (51) (42)
Prior service (credit) cost amortization included in benefit cost (40) (43) (49)
Settlements and curtailments (3) 0 (1)
Total (88) (94) (92)
United States | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Net gain (loss) arising during the period 408 35 (69)
Prior service credit (cost) arising during the period 0 0 0
Total 408 35 (69)
Net loss (gain) amortization included in benefit cost 58 43 0
Prior service (credit) cost amortization included in benefit cost 0 0 (1)
Settlements and curtailments 9 0 36
Total 67 43 35
International | Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Net gain (loss) arising during the period 686 634 (438)
Prior service credit (cost) arising during the period 5 56 (16)
Total 691 690 (454)
Net loss (gain) amortization included in benefit cost 11 5 (3)
Prior service (credit) cost amortization included in benefit cost (28) (13) 2
Settlements and curtailments (15) (1) (6)
Total $ (32) $ (9) $ (7)
v3.25.4
Pension and Other Postretirement Benefit Plans - Summary of Weighted Average Assumptions Used in Determining Pension Plan and U.S. Pension and Other Postretirement Benefit Plan Information (Details)
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
United States      
Net periodic benefit cost      
Discount rate 5.70% 5.30% 5.50%
Expected rate of return on plan assets 7.70% 7.75% 7.00%
Salary growth rate 4.80% 4.60% 4.60%
Interest crediting rate 5.40% 5.30% 5.30%
Benefit obligation      
Discount rate 5.60% 5.70% 5.30%
Salary growth rate 4.80% 4.80% 4.60%
Interest crediting rate 5.40% 5.40% 5.30%
International | Pension Benefits      
Net periodic benefit cost      
Discount rate 3.70% 3.40% 3.90%
Expected rate of return on plan assets 5.40% 5.20% 5.00%
Salary growth rate 3.10% 3.20% 3.20%
Interest crediting rate 3.50% 3.40% 3.30%
Benefit obligation      
Discount rate 4.20% 3.70% 3.40%
Salary growth rate 3.10% 3.10% 3.20%
Interest crediting rate 3.70% 3.50% 3.40%
v3.25.4
Pension and Other Postretirement Benefit Plans - Summary of Health Care Cost Trend Rate Assumptions for Other Postretirement Benefit Plans (Details) - Other Postretirement Benefits
Dec. 31, 2025
Dec. 31, 2024
Defined Benefit Plan Disclosure [Line Items]    
Health care cost trend rate assumed for next year 8.50% 7.90%
Rate to which the cost trend rate is assumed to decline 4.50% 4.50%
v3.25.4
Other (Income) Expense, Net - Schedule of Other (Income) Expense, Net (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Other Income and Expenses [Abstract]      
Interest income $ (343) $ (415) $ (365)
Interest expense 1,357 1,271 1,146
Exchange losses 323 227 370
Income from investments in equity securities, net (368) (14) (340)
Net periodic defined benefit plan (credit) cost other than service cost (615) (633) (498)
Other, net (203) (460) 153
Other (income) expense, net $ 151 $ (24) $ 466
v3.25.4
Other (Income) Expense, Net - Narrative (Details) - USD ($)
$ in Millions
1 Months Ended 12 Months Ended
Aug. 31, 2024
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Component of Other Income / Expense of Nonoperating [Line Items]        
Interest paid   $ 1,300.0 $ 1,300.0 $ 1,100.0
Zetia antitrust litigation        
Component of Other Income / Expense of Nonoperating [Line Items]        
Loss related to settlement litigation       $ 572.5
Daiichi Sankyo | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement        
Component of Other Income / Expense of Nonoperating [Line Items]        
Upfront cash payment $ 170.0      
v3.25.4
Tax Income - Schedule of Reconciliation Between Effective Tax Rate and U.S. Statutory Rate (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Amount      
U.S. statutory rate applied to income before taxes $ 4,424 $ 4,186 $ 397
State and local income taxes, net of federal benefit 12 (39) (117)
Tax rate differential   (1,301) (941)
Other   80 (13)
Net controlled foreign corporation tested income 3,759    
Foreign-derived deduction-eligible income (31)    
Subpart F 227    
Research and development tax credits (260) (202) (214)
Valuation allowances 76 54 70
Nontaxable or nondeductible items (78)    
Changes in unrecognized tax benefits 341    
Taxes on income $ 2,804 $ 2,803 $ 1,512
Tax Rate      
U.S. statutory rate applied to income before taxes 21.00% 21.00% 21.00%
State and local income taxes, net of federal benefit 0.10% (0.20%) (6.20%)
Tax rate differential   (6.50%) (49.80%)
Other   0.40% (0.70%)
Net controlled foreign corporation tested income 17.80%    
Foreign-derived deduction-eligible income (0.10%)    
Subpart F 1.10%    
Research and development tax credits (1.20%) (1.00%) (11.30%)
Valuation allowances 0.40% 0.30% 3.70%
Nontaxable or nondeductible items (0.40%)    
Changes in unrecognized tax benefits 1.50%    
Total, Tax Rate 13.30% 14.10% 80.00%
Switzerland      
Amount      
Tax rate differential $ (1,428)    
Withholding taxes 284    
Other $ 59    
Tax Rate      
Tax rate differential (6.80%)    
Withholding taxes 1.30%    
Other 0.30%    
Netherlands      
Amount      
Tax rate differential $ 409    
Other (66)    
Innovation box $ (1,042)    
Tax Rate      
Tax rate differential 1.90%    
Other (0.30%)    
Innovation box (4.90%)    
Other foreign jurisdictions      
Amount      
Tax rate differential $ 308    
Tax Rate      
Tax rate differential 1.50%    
United States      
Amount      
Foreign tax credits $ (4,190)    
Tax Rate      
Foreign tax credits (19.90%)    
v3.25.4
Tax Income - Schedule of Reconciliation Between Effective Tax Rate and U.S. Statutory Rate (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Amount      
U.S. statutory rate applied to income before taxes $ 4,424 $ 4,186 $ 397
Foreign earnings   (1,301) (941)
Tax settlements and statute lapses   (557) 0
R&D tax credit (260) (202) (214)
Inventory donations   (71) (65)
State taxes 12 (39) (117)
Charges for certain research and development asset acquisitions   554 253
Valuation allowances 76 54 70
Restructuring   52 41
Effect of cross-border tax laws:   29 (80)
Acquisition-related costs, including amortization   18 42
Acquisition of Prometheus   0 2,139
Other   80 (13)
Taxes on income $ 2,804 $ 2,803 $ 1,512
Tax Rate      
U.S. statutory rate applied to income before taxes 21.00% 21.00% 21.00%
Foreign earnings   (6.50%) (49.80%)
Effective Income Tax Rate Reconciliation, Tax Settlement, Percent   (2.80%) 0.00%
R&D tax credit (1.20%) (1.00%) (11.30%)
Inventory donations   (0.40%) (3.50%)
State taxes 0.10% (0.20%) (6.20%)
Effective Income Tax Rate Reconciliation, Asset Acquisition Two, Percent   2.80% 13.40%
Valuation allowances 0.40% 0.30% 3.70%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Restructuring Charges, Percent   0.30% 2.20%
Effect of cross-border tax laws:   0.10% (4.30%)
Effective Income Tax Rate Reconciliation, Acquisition-Related Costs And Amortization, Percent   0.10% 2.20%
Effective Income Tax Rate Reconciliation, Asset Acquisition Three, Percent   0.00% 113.30%
Other   0.40% (0.70%)
Total, Tax Rate 13.30% 14.10% 80.00%
v3.25.4
Taxes on Income - Narrative (Details) - USD ($)
$ in Millions
1 Months Ended 12 Months Ended
Apr. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Income Tax Contingency [Line Items]          
Tax Cuts and Jobs Act payment   $ 1,200      
Transition tax asset, credit, noncurrent   702      
Deferred tax assets on NOL carryforwards relating to foreign jurisdictions   384      
Deferred tax assets relating to various U.S. tax credit carryforwards and NOL carryforwards   813      
Prepaid taxes   5,700 $ 3,900    
Tax benefits relating to stock option exercises   7 26 $ 12  
Unrecognized tax benefits   2,530 2,261 2,384 $ 1,835
Favorable net impact to income tax provision if unrecognized tax benefits were recognized   2,500      
Interest and penalties associated with uncertain tax positions, expense (benefit)   106 51 $ 131  
Liabilities for accrued interest and penalties   546 437    
Internal Revenue Service (IRS)          
Income Tax Contingency [Line Items]          
Income tax examination, estimate of possible loss $ 1,300        
Penalties | Internal Revenue Service (IRS)          
Income Tax Contingency [Line Items]          
Income tax examination, estimate of possible loss $ 260        
Tax Year 2019 and 2020          
Income Tax Contingency [Line Items]          
Reduction in reserves resulting from lapse of statute of limitations     $ 519    
Foreign Jurisdiction          
Income Tax Contingency [Line Items]          
Valuation allowance on foreign NOL carryforwards   248      
Federal          
Income Tax Contingency [Line Items]          
Valuation allowance on foreign NOL carryforwards   $ 576      
v3.25.4
Taxes on Income - Schedule of Income Before Taxes (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Income Tax Disclosure [Abstract]      
Domestic $ (4,948) $ (1,849) $ (15,622)
Foreign 26,015 21,785 17,511
Income Before Taxes $ 21,067 $ 19,936 $ 1,889
v3.25.4
Taxes on Income - Schedule of Taxes on Income (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Current provision      
Federal $ 499 $ 944 $ 928
Foreign 4,072 3,123 2,435
State (96) (15) 48
Total current provision 4,475 4,052 3,411
Deferred provision      
Federal (1,585) (1,475) (1,559)
Foreign (83) 212 (233)
State (3) 14 (107)
Total deferred provision (1,671) (1,249) (1,899)
Taxes on income $ 2,804 $ 2,803 $ 1,512
v3.25.4
Taxes on Income - Schedule of Deferred Income Taxes (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Income Tax [Line Items]    
Product intangibles and licenses, Assets $ 140 $ 71
Product intangibles and licenses, Liabilities 3,272 978
R&D capitalization, Assets 4,134 3,062
Inventory related, Assets 72 84
Inventory related, Liabilities 451 413
Accelerated depreciation, Liabilities 594 645
Undistributed foreign earnings, Assets 119 275
Undistributed foreign earnings, Liabilities 338 371
Equity method investments, Liabilities 155 90
Pensions and other postretirement benefits, Assets 117 224
Pensions and other postretirement benefits, Liabilities 623 400
Compensation related, Assets 382 400
Unrecognized tax benefits, Assets 160 152
Net operating losses and other tax credit carryforwards, Assets 1,197 910
Other, Assets 1,236 802
Other, Liabilities 134 159
Subtotal, Assets 7,557 5,980
Subtotal, Liabilities 5,567 3,056
Valuation allowance, Assets (824) (710)
Total deferred taxes 6,733 5,270
Deferred income taxes, Assets 1,166 2,214
Deferred Income Taxes 1,439 1,387
Other Assets    
Income Tax [Line Items]    
Total deferred taxes $ 2,605 $ 3,601
v3.25.4
Taxes on Income - Schedule of Income Taxes Paid by Jurisdiction (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Income Tax Contingency [Line Items]      
Domestic - federal $ 1,559 $ 974 $ 2,258
Domestic - state and local 24    
Foreign   2,954 2,080
Income taxes paid 6,086 $ 3,928 $ 4,338
Switzerland      
Income Tax Contingency [Line Items]      
Foreign 2,115    
Netherlands      
Income Tax Contingency [Line Items]      
Foreign 1,576    
Other foreign      
Income Tax Contingency [Line Items]      
Foreign $ 812    
v3.25.4
Taxes on Income - Schedule of Unrecognized Tax Benefits (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Reconciliation of Unrecognized Tax Benefits [Roll Forward]      
Balance January 1 $ 2,261 $ 2,384 $ 1,835
Additions related to current year positions 396 421 553
Additions related to prior year positions 59 35 91
Reductions for tax positions of prior years (94) (33) (20)
Settlements (28) (18) (23)
Lapse of statute of limitations (64) (528) (52)
Balance December 31 $ 2,530 2,261 $ 2,384
Tax Year 2019 and 2020      
Reconciliation of Unrecognized Tax Benefits [Roll Forward]      
Lapse of statute of limitations   $ (451)  
v3.25.4
Earnings Per Share - Schedule of Calculations of Earnings Per Share (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Earnings Per Share [Abstract]      
Net income attributable to Merck & Co., Inc., basic $ 18,254 $ 17,117 $ 365
Net income attributable to Merck & Co., Inc., diluted $ 18,254 $ 17,117 $ 365
Average common shares outstanding (in shares) 2,502 2,532 2,537
Common shares issuable (in shares) 5 9 10
Average common shares outstanding assuming dilution (in shares) 2,507 2,541 2,547
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 7.30 $ 6.76 $ 0.14
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders (in dollars per share) $ 7.28 $ 6.74 $ 0.14
v3.25.4
Earnings Per Share - Narrative (Details) - shares
shares in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Earnings Per Share [Abstract]      
Antidilutive shares (in shares) 11 6 5
v3.25.4
Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Beginning balance $ 46,372 $ 37,635 $ 46,058
Other comprehensive income (loss), net of taxes 658 216 (393)
Ending balance 52,662 46,372 37,635
Derivatives      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Beginning balance 242 (24) 73
Other comprehensive income (loss) before reclassification adjustments, pretax (577) 508 114
Tax 124 (109) (24)
Other comprehensive income (loss) before reclassification adjustments, net of taxes (453) 399 90
Reclassification adjustments, pretax 134 (168) (237)
Tax (28) 35 50
Reclassification adjustments, net of taxes 106 (133) (187)
Other comprehensive income (loss), net of taxes (347) 266 (97)
Ending balance (105) 242 (24)
Employee Benefit Plans      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Beginning balance (2,327) (2,793) (2,408)
Other comprehensive income (loss) before reclassification adjustments, pretax 1,101 647 (413)
Tax (232) (138) 86
Other comprehensive income (loss) before reclassification adjustments, net of taxes 869 509 (327)
Reclassification adjustments, pretax (53) (60) (64)
Tax 12 17 6
Reclassification adjustments, net of taxes (41) (43) (58)
Other comprehensive income (loss), net of taxes 828 466 (385)
Ending balance (1,499) (2,327) (2,793)
Pension Plan Net Loss      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Pension and other postretirement benefit plans, net loss (gain) and prior service (credit) included in AOCI 2,000 3,000  
Other Postretirement Benefit Plan Net Gain      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Pension and other postretirement benefit plans, net loss (gain) and prior service (credit) included in AOCI (365) (400)  
Pension Plan Prior Service Credit      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Pension and other postretirement benefit plans, net loss (gain) and prior service (credit) included in AOCI (146) (174)  
Other Postretirement Benefit Plan Prior Service Credit      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Pension and other postretirement benefit plans, net loss (gain) and prior service (credit) included in AOCI (29) (61)  
Foreign Currency Translation Adjustment      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Beginning balance (2,860) (2,344) (2,433)
Other comprehensive income (loss) before reclassification adjustments, pretax 254 (559) 17
Tax (77) 23 63
Other comprehensive income (loss) before reclassification adjustments, net of taxes 177 (536) 80
Reclassification adjustments, pretax 0 20 9
Tax 0 0 0
Reclassification adjustments, net of taxes 0 20 9
Other comprehensive income (loss), net of taxes 177 (516) 89
Ending balance (2,683) (2,860) (2,344)
Accumulated Other Comprehensive Loss      
Accumulated Other Comprehensive Income (Loss) [Roll Forward]      
Beginning balance (4,945) (5,161) (4,768)
Other comprehensive income (loss) before reclassification adjustments, pretax 778 596 (282)
Tax (185) (224) 125
Other comprehensive income (loss) before reclassification adjustments, net of taxes 593 372 (157)
Reclassification adjustments, pretax 81 (208) (292)
Tax (16) 52 56
Reclassification adjustments, net of taxes 65 (156) (236)
Other comprehensive income (loss), net of taxes 658 216 (393)
Ending balance $ (4,287) $ (4,945) $ (5,161)
v3.25.4
Segment Reporting - Narrative (Details)
12 Months Ended
Dec. 31, 2025
segment
Segment Reporting [Abstract]  
Number of operating segments 2
Number of reportable segments 2
v3.25.4
Segment Reporting - Schedule of Sales of Company's Products (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Segment Reporting Information [Line Items]      
Sales $ 65,011 $ 64,168 $ 60,115
Increase (decrease) in revenue hedging activities (127) 195 244
Revenue related to the sale of the marketing rights 138 106 118
AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Segment Reporting Information [Line Items]      
Revenue from collaborative arrangement 1,886 1,481 1,296
Alliance revenue - Lynparza | AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Segment Reporting Information [Line Items]      
Revenue from collaborative arrangement 1,450 1,311 1,199
Alliance revenue - Koselugo | AstraZeneca | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement      
Segment Reporting Information [Line Items]      
Revenue from collaborative arrangement 436 170 97
Operating Segments      
Segment Reporting Information [Line Items]      
Sales 64,496 63,277 59,208
Operating Segments | Pharmaceutical      
Segment Reporting Information [Line Items]      
Sales 58,142 57,400 53,583
Operating Segments | Pharmaceutical | Keytruda      
Segment Reporting Information [Line Items]      
Sales 31,641 29,482 25,011
Operating Segments | Pharmaceutical | Keytruda Qlex      
Segment Reporting Information [Line Items]      
Sales 40 0 0
Operating Segments | Pharmaceutical | Alliance revenue - Lynparza      
Segment Reporting Information [Line Items]      
Sales 1,450 1,311 1,199
Operating Segments | Pharmaceutical | Alliance revenue - Lenvima      
Segment Reporting Information [Line Items]      
Sales 1,053 1,010 960
Operating Segments | Pharmaceutical | Welireg      
Segment Reporting Information [Line Items]      
Sales 716 509 218
Operating Segments | Pharmaceutical | Alliance revenue - Reblozyl      
Segment Reporting Information [Line Items]      
Sales 525 371 212
Operating Segments | Pharmaceutical | Gardasil/Gardasil 9      
Segment Reporting Information [Line Items]      
Sales 5,233 8,583 8,886
Operating Segments | Pharmaceutical | ProQuad/M-M-R II/Varivax      
Segment Reporting Information [Line Items]      
Sales 2,451 2,485 2,368
Operating Segments | Pharmaceutical | Vaxneuvance      
Segment Reporting Information [Line Items]      
Sales 825 808 665
Operating Segments | Pharmaceutical | Capvaxive      
Segment Reporting Information [Line Items]      
Sales 759 97 0
Operating Segments | Pharmaceutical | RotaTeq      
Segment Reporting Information [Line Items]      
Sales 673 711 769
Operating Segments | Pharmaceutical | Pneumovax 23      
Segment Reporting Information [Line Items]      
Sales 166 263 412
Operating Segments | Pharmaceutical | Bridion      
Segment Reporting Information [Line Items]      
Sales 1,841 1,764 1,842
Operating Segments | Pharmaceutical | Prevymis      
Segment Reporting Information [Line Items]      
Sales 978 785 605
Operating Segments | Pharmaceutical | Zerbaxa      
Segment Reporting Information [Line Items]      
Sales 312 252 218
Operating Segments | Pharmaceutical | Dificid      
Segment Reporting Information [Line Items]      
Sales 247 340 302
Operating Segments | Pharmaceutical | Winrevair      
Segment Reporting Information [Line Items]      
Sales 1,443 419 0
Operating Segments | Pharmaceutical | Alliance revenue - Adempas/Verquvo      
Segment Reporting Information [Line Items]      
Sales 470 415 367
Operating Segments | Pharmaceutical | Adempas      
Segment Reporting Information [Line Items]      
Sales 312 287 255
Operating Segments | Pharmaceutical | Ohtuvayre      
Segment Reporting Information [Line Items]      
Sales 178 0 0
Operating Segments | Pharmaceutical | Lagevrio      
Segment Reporting Information [Line Items]      
Sales 380 964 1,428
Operating Segments | Pharmaceutical | Isentress/Isentress HD      
Segment Reporting Information [Line Items]      
Sales 325 394 483
Operating Segments | Pharmaceutical | Delstrigo      
Segment Reporting Information [Line Items]      
Sales 306 249 201
Operating Segments | Pharmaceutical | Pifeltro      
Segment Reporting Information [Line Items]      
Sales 171 163 142
Operating Segments | Pharmaceutical | Belsomra      
Segment Reporting Information [Line Items]      
Sales 186 222 231
Operating Segments | Pharmaceutical | Simponi      
Segment Reporting Information [Line Items]      
Sales 0 543 710
Operating Segments | Pharmaceutical | Remicade      
Segment Reporting Information [Line Items]      
Sales 0 114 187
Operating Segments | Pharmaceutical | Januvia      
Segment Reporting Information [Line Items]      
Sales 1,604 1,334 2,189
Operating Segments | Pharmaceutical | Janumet      
Segment Reporting Information [Line Items]      
Sales 940 935 1,177
Operating Segments | Pharmaceutical | Other pharmaceutical      
Segment Reporting Information [Line Items]      
Sales 2,917 2,590 2,546
Operating Segments | Animal Health      
Segment Reporting Information [Line Items]      
Sales 6,354 5,877 5,625
Operating Segments | Animal Health | Livestock      
Segment Reporting Information [Line Items]      
Sales 3,896 3,462 3,337
Operating Segments | Animal Health | Companion Animal      
Segment Reporting Information [Line Items]      
Sales 2,458 2,415 2,288
Other      
Segment Reporting Information [Line Items]      
Sales 515 891 907
United States      
Segment Reporting Information [Line Items]      
Sales 36,510 32,277 28,480
United States | Operating Segments      
Segment Reporting Information [Line Items]      
Sales 36,362 32,151 28,343
United States | Operating Segments | Pharmaceutical      
Segment Reporting Information [Line Items]      
Sales 34,409 30,290 26,539
United States | Operating Segments | Pharmaceutical | Keytruda      
Segment Reporting Information [Line Items]      
Sales 18,829 17,872 15,114
United States | Operating Segments | Pharmaceutical | Keytruda Qlex      
Segment Reporting Information [Line Items]      
Sales 38 0 0
United States | Operating Segments | Pharmaceutical | Alliance revenue - Lynparza      
Segment Reporting Information [Line Items]      
Sales 683 626 607
United States | Operating Segments | Pharmaceutical | Alliance revenue - Lenvima      
Segment Reporting Information [Line Items]      
Sales 737 705 657
United States | Operating Segments | Pharmaceutical | Welireg      
Segment Reporting Information [Line Items]      
Sales 603 466 209
United States | Operating Segments | Pharmaceutical | Alliance revenue - Reblozyl      
Segment Reporting Information [Line Items]      
Sales 432 303 168
United States | Operating Segments | Pharmaceutical | Gardasil/Gardasil 9      
Segment Reporting Information [Line Items]      
Sales 2,641 2,425 2,083
United States | Operating Segments | Pharmaceutical | ProQuad/M-M-R II/Varivax      
Segment Reporting Information [Line Items]      
Sales 1,885 1,919 1,837
United States | Operating Segments | Pharmaceutical | Vaxneuvance      
Segment Reporting Information [Line Items]      
Sales 459 461 561
United States | Operating Segments | Pharmaceutical | Capvaxive      
Segment Reporting Information [Line Items]      
Sales 730 96 0
United States | Operating Segments | Pharmaceutical | RotaTeq      
Segment Reporting Information [Line Items]      
Sales 426 472 493
United States | Operating Segments | Pharmaceutical | Pneumovax 23      
Segment Reporting Information [Line Items]      
Sales 21 56 127
United States | Operating Segments | Pharmaceutical | Bridion      
Segment Reporting Information [Line Items]      
Sales 1,631 1,401 1,156
United States | Operating Segments | Pharmaceutical | Prevymis      
Segment Reporting Information [Line Items]      
Sales 475 371 264
United States | Operating Segments | Pharmaceutical | Zerbaxa      
Segment Reporting Information [Line Items]      
Sales 186 146 119
United States | Operating Segments | Pharmaceutical | Dificid      
Segment Reporting Information [Line Items]      
Sales 202 303 274
United States | Operating Segments | Pharmaceutical | Winrevair      
Segment Reporting Information [Line Items]      
Sales 1,358 408 0
United States | Operating Segments | Pharmaceutical | Alliance revenue - Adempas/Verquvo      
Segment Reporting Information [Line Items]      
Sales 421 388 350
United States | Operating Segments | Pharmaceutical | Adempas      
Segment Reporting Information [Line Items]      
Sales 0 0 0
United States | Operating Segments | Pharmaceutical | Ohtuvayre      
Segment Reporting Information [Line Items]      
Sales 178 0 0
United States | Operating Segments | Pharmaceutical | Lagevrio      
Segment Reporting Information [Line Items]      
Sales 101 176 10
United States | Operating Segments | Pharmaceutical | Isentress/Isentress HD      
Segment Reporting Information [Line Items]      
Sales 181 185 215
United States | Operating Segments | Pharmaceutical | Delstrigo      
Segment Reporting Information [Line Items]      
Sales 56 56 49
United States | Operating Segments | Pharmaceutical | Pifeltro      
Segment Reporting Information [Line Items]      
Sales 111 113 101
United States | Operating Segments | Pharmaceutical | Belsomra      
Segment Reporting Information [Line Items]      
Sales 82 72 81
United States | Operating Segments | Pharmaceutical | Simponi      
Segment Reporting Information [Line Items]      
Sales 0 0 0
United States | Operating Segments | Pharmaceutical | Remicade      
Segment Reporting Information [Line Items]      
Sales 0 0 0
United States | Operating Segments | Pharmaceutical | Januvia      
Segment Reporting Information [Line Items]      
Sales 999 469 1,151
United States | Operating Segments | Pharmaceutical | Janumet      
Segment Reporting Information [Line Items]      
Sales 268 161 223
United States | Operating Segments | Pharmaceutical | Other pharmaceutical      
Segment Reporting Information [Line Items]      
Sales 676 640 690
United States | Operating Segments | Animal Health      
Segment Reporting Information [Line Items]      
Sales 1,953 1,861 1,804
United States | Operating Segments | Animal Health | Livestock      
Segment Reporting Information [Line Items]      
Sales 807 732 700
United States | Operating Segments | Animal Health | Companion Animal      
Segment Reporting Information [Line Items]      
Sales 1,146 1,129 1,104
United States | Other      
Segment Reporting Information [Line Items]      
Sales 148 126 137
Int’l      
Segment Reporting Information [Line Items]      
Sales 28,501 31,891 31,635
Int’l | Operating Segments      
Segment Reporting Information [Line Items]      
Sales 28,134 31,126 30,865
Int’l | Operating Segments | Pharmaceutical      
Segment Reporting Information [Line Items]      
Sales 23,733 27,110 27,044
Int’l | Operating Segments | Pharmaceutical | Keytruda      
Segment Reporting Information [Line Items]      
Sales 12,812 11,610 9,897
Int’l | Operating Segments | Pharmaceutical | Keytruda Qlex      
Segment Reporting Information [Line Items]      
Sales 2 0 0
Int’l | Operating Segments | Pharmaceutical | Alliance revenue - Lynparza      
Segment Reporting Information [Line Items]      
Sales 767 685 592
Int’l | Operating Segments | Pharmaceutical | Alliance revenue - Lenvima      
Segment Reporting Information [Line Items]      
Sales 316 305 303
Int’l | Operating Segments | Pharmaceutical | Welireg      
Segment Reporting Information [Line Items]      
Sales 113 43 10
Int’l | Operating Segments | Pharmaceutical | Alliance revenue - Reblozyl      
Segment Reporting Information [Line Items]      
Sales 93 68 43
Int’l | Operating Segments | Pharmaceutical | Gardasil/Gardasil 9      
Segment Reporting Information [Line Items]      
Sales 2,592 6,158 6,803
Int’l | Operating Segments | Pharmaceutical | ProQuad/M-M-R II/Varivax      
Segment Reporting Information [Line Items]      
Sales 566 566 531
Int’l | Operating Segments | Pharmaceutical | Vaxneuvance      
Segment Reporting Information [Line Items]      
Sales 366 347 103
Int’l | Operating Segments | Pharmaceutical | Capvaxive      
Segment Reporting Information [Line Items]      
Sales 29 1 0
Int’l | Operating Segments | Pharmaceutical | RotaTeq      
Segment Reporting Information [Line Items]      
Sales 246 239 276
Int’l | Operating Segments | Pharmaceutical | Pneumovax 23      
Segment Reporting Information [Line Items]      
Sales 146 207 285
Int’l | Operating Segments | Pharmaceutical | Bridion      
Segment Reporting Information [Line Items]      
Sales 209 363 686
Int’l | Operating Segments | Pharmaceutical | Prevymis      
Segment Reporting Information [Line Items]      
Sales 503 414 341
Int’l | Operating Segments | Pharmaceutical | Zerbaxa      
Segment Reporting Information [Line Items]      
Sales 126 106 100
Int’l | Operating Segments | Pharmaceutical | Dificid      
Segment Reporting Information [Line Items]      
Sales 45 37 28
Int’l | Operating Segments | Pharmaceutical | Winrevair      
Segment Reporting Information [Line Items]      
Sales 85 11 0
Int’l | Operating Segments | Pharmaceutical | Alliance revenue - Adempas/Verquvo      
Segment Reporting Information [Line Items]      
Sales 49 27 16
Int’l | Operating Segments | Pharmaceutical | Adempas      
Segment Reporting Information [Line Items]      
Sales 312 287 255
Int’l | Operating Segments | Pharmaceutical | Ohtuvayre      
Segment Reporting Information [Line Items]      
Sales 0 0 0
Int’l | Operating Segments | Pharmaceutical | Lagevrio      
Segment Reporting Information [Line Items]      
Sales 278 787 1,418
Int’l | Operating Segments | Pharmaceutical | Isentress/Isentress HD      
Segment Reporting Information [Line Items]      
Sales 144 209 268
Int’l | Operating Segments | Pharmaceutical | Delstrigo      
Segment Reporting Information [Line Items]      
Sales 250 193 152
Int’l | Operating Segments | Pharmaceutical | Pifeltro      
Segment Reporting Information [Line Items]      
Sales 59 50 41
Int’l | Operating Segments | Pharmaceutical | Belsomra      
Segment Reporting Information [Line Items]      
Sales 104 150 150
Int’l | Operating Segments | Pharmaceutical | Simponi      
Segment Reporting Information [Line Items]      
Sales 0 543 710
Int’l | Operating Segments | Pharmaceutical | Remicade      
Segment Reporting Information [Line Items]      
Sales 0 114 187
Int’l | Operating Segments | Pharmaceutical | Januvia      
Segment Reporting Information [Line Items]      
Sales 605 865 1,039
Int’l | Operating Segments | Pharmaceutical | Janumet      
Segment Reporting Information [Line Items]      
Sales 672 774 954
Int’l | Operating Segments | Pharmaceutical | Other pharmaceutical      
Segment Reporting Information [Line Items]      
Sales 2,244 1,951 1,856
Int’l | Operating Segments | Animal Health      
Segment Reporting Information [Line Items]      
Sales 4,401 4,016 3,821
Int’l | Operating Segments | Animal Health | Livestock      
Segment Reporting Information [Line Items]      
Sales 3,089 2,729 2,637
Int’l | Operating Segments | Animal Health | Companion Animal      
Segment Reporting Information [Line Items]      
Sales 1,312 1,287 1,184
Int’l | Other      
Segment Reporting Information [Line Items]      
Sales $ 367 $ 765 $ 770
v3.25.4
Segment Reporting - Schedule of Consolidated Revenues by Geographic Area (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Revenues from External Customers and Long-Lived Assets [Line Items]      
Sales $ 65,011 $ 64,168 $ 60,115
United States      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Sales 36,510 32,277 28,480
Europe, Middle East and Africa      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Sales 14,580 14,041 13,254
Latin America      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Sales 3,410 3,459 3,086
Asia Pacific (other than Japan and China)      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Sales 2,983 3,058 3,225
Japan      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Sales 2,711 3,280 3,164
China      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Sales 1,939 5,494 6,802
Other      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Sales $ 2,878 $ 2,559 $ 2,104
v3.25.4
Segment Reporting - Schedule of Reconciliation of Segment Profits to Income Before Taxes (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Segment Reporting Information [Line Items]      
Sales $ 65,011 $ 64,168 $ 60,115
Cost of sales 16,382 15,193 16,126
Selling, general and administrative 10,733 10,816 10,504
Research and development 15,789 17,938 30,531
Other segment items 151 (24) 466
Income Before Taxes 21,067 19,936 1,889
Interest income 343 415 365
Interest expense (1,357) (1,271) (1,146)
Amortization (2,793) (2,395) (2,044)
Depreciation (3,045) (2,104) (1,828)
Research and development (15,789) (17,938) (30,531)
Restructuring costs (889) (309) (599)
Total segment profits      
Segment Reporting Information [Line Items]      
Sales 64,496 63,277 59,208
Income Before Taxes 47,885 46,471 40,617
Depreciation (287) (261) (203)
Total segment profits | Pharmaceutical      
Segment Reporting Information [Line Items]      
Sales 58,142 57,400 53,583
Cost of sales 6,679 6,828 8,849
Selling, general and administrative 5,874 6,128 5,903
Research and development 0 0 0
Other segment items (165) (89) (49)
Income Before Taxes 45,754 44,533 38,880
Depreciation (5) (5) (5)
Research and development 0 0 0
Total segment profits | Animal Health      
Segment Reporting Information [Line Items]      
Sales 6,354 5,877 5,625
Cost of sales 2,649 2,469 2,498
Selling, general and administrative 1,125 1,084 1,038
Research and development 448 385 353
Other segment items 1 1 (1)
Income Before Taxes 2,131 1,938 1,737
Depreciation (282) (256) (198)
Research and development (448) (385) (353)
Other profits      
Segment Reporting Information [Line Items]      
Sales 515 891 907
Research and development 14,987 17,350 30,008
Income Before Taxes 251 492 474
Interest income 343 415 365
Interest expense (1,357) (1,271) (1,146)
Amortization (2,793) (2,395) (2,044)
Depreciation (2,758) (1,843) (1,625)
Research and development (14,987) (17,350) (30,008)
Restructuring costs (889) (309) (599)
Charge for Zetia antitrust litigation settlements 0 0 (573)
Other unallocated, net $ (4,628) $ (4,274) $ (3,572)
v3.25.4
Segment Reporting - Schedule of Equity Income from Affiliates and Depreciation Included in Segment Profits (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Segment Reporting Information [Line Items]      
Depreciation $ 3,045 $ 2,104 $ 1,828
Operating Segments      
Segment Reporting Information [Line Items]      
Equity income from affiliates 190 144 111
Depreciation 287 261 203
Operating Segments | Pharmaceutical      
Segment Reporting Information [Line Items]      
Equity income from affiliates 190 144 111
Depreciation 5 5 5
Operating Segments | Animal Health      
Segment Reporting Information [Line Items]      
Equity income from affiliates 0 0 0
Depreciation $ 282 $ 256 $ 198
v3.25.4
Segment Reporting - Schedule of Property, Plant and Equipment, Net by Geographic Area (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Revenues from External Customers and Long-Lived Assets [Line Items]      
Property, plant and equipment, net $ 25,316 $ 23,779 $ 23,051
United States      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Property, plant and equipment, net 15,021 14,724 13,915
Europe, Middle East and Africa      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Property, plant and equipment, net 8,856 7,548 7,562
Asia Pacific (other than Japan and China)      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Property, plant and equipment, net 898 982 1,022
China      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Property, plant and equipment, net 218 202 193
Japan      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Property, plant and equipment, net 144 143 133
Latin America      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Property, plant and equipment, net 128 133 222
Other      
Revenues from External Customers and Long-Lived Assets [Line Items]      
Property, plant and equipment, net $ 51 $ 47 $ 4