Acquisitions, Research Collaborations and License Agreements	9 Months Ended
	Sep. 30, 2022
Business Combination and Asset Acquisition [Abstract]
Acquisitions, Research Collaborations and License Agreements	Acquisitions, Research Collaborations and License Agreements The Company continues to pursue acquisitions and the establishment of external alliances such as research collaborations and licensing agreements to complement its internal research capabilities. These arrangements often include upfront payments, as well as expense reimbursements or payments to the third party, and milestone, royalty or profit share arrangements, contingent upon the occurrence of certain future events linked to the success of the asset in development. The Company also reviews its marketed products and pipeline to examine candidates which may provide more value through out-licensing and, as part of its portfolio assessment process, may also divest certain assets. Pro forma financial information for acquired businesses is not presented if the historical financial results of the acquired entity are not significant when compared with the Company’s financial results. 2022 Transactions In October 2022, Merck and Royalty Pharma plc (Royalty Pharma) entered into a funding arrangement under which Royalty Pharma paid Merck $50 million to co-fund Merck’s development costs for a Phase 2b trial of MK-8189, an investigational oral Phosphodiesterase 10A (PDE10A) inhibitor, which is being evaluated for the treatment of schizophrenia. Under the agreement, Royalty Pharma has no rights to MK-8189 and has no decision-making authority over the program. If Merck elects to advance MK-8189 into a Phase 3 study, Royalty Pharma has the option to provide additional funding of 50% of the development costs up to $375 million for the Phase 3 trial. If such additional funding is provided, Royalty Pharma becomes eligible to receive future regulatory milestone payments contingent upon certain marketing approvals, as well as royalties. In September 2022, Merck exercised its option to jointly develop and commercialize personalized cancer vaccine mRNA-4157/V940 pursuant to the terms of an existing collaboration and license agreement with Moderna, Inc. (Moderna), which resulted in a $250 million charge in Research and development expenses in the third quarter and first nine months of 2022. The payment to Moderna was made in the fourth quarter of 2022. mRNA-4157/V940 is currently being evaluated in combination with Keytruda (pembrolizumab), Merck’s anti-PD-1 therapy, as adjuvant treatment for patients with high-risk melanoma in a Phase 2 clinical trial being conducted by Moderna. Under the 2016 agreement, as amended in 2018, Merck and Moderna will collaborate on development and commercialization and will share costs and any profits equally under this worldwide collaboration. In August 2022, Merck and Orna Therapeutics (Orna), a biotechnology company pioneering a new investigational class of engineered circular RNA (oRNA) therapies, entered into a collaboration agreement to discover, develop, and commercialize multiple programs, including vaccines and therapeutics in the areas of infectious disease and oncology. Under the terms of the agreement, Merck made an upfront payment to Orna of $150 million, which was recorded in Research and development expenses in the third quarter and first nine months of 2022. In addition, Orna is eligible to receive future contingent development-related payments aggregating up to $440 million, $675 million in regulatory milestones, and $2.4 billion in sales milestones associated with the progress of the multiple vaccine and therapeutic programs, as well as royalties ranging from a high-single-digit rate to a low-double-digit rate on any approved products derived from the collaboration. Merck also invested $100 million in Orna’s Series B preferred shares in the fourth quarter of 2022. In July 2022, Merck and Orion Corporation (Orion) announced a global co-development and co-commercialization agreement for Orion’s investigational candidate ODM-208 (MK-5684) and other drugs targeting cytochrome P450 11A1 (CYP11A1), an enzyme important in steroid production. ODM-208 is an oral, non-steroidal inhibitor of CYP11A1 currently being evaluated in a Phase 2 clinical trial for the treatment of patients with metastatic castration-resistant prostate cancer. Merck made an upfront payment to Orion of $290 million, which was recorded in Research and development expenses in the third quarter and first nine months of 2022. Orion is responsible for the manufacture of clinical and commercial supply of ODM-208. In addition, the contract provides both parties with an option to convert the initial co-development and co-commercialization agreement into a global exclusive license to Merck. If the option is exercised, Merck would assume full responsibility for all past development and commercialization expenses associated with the program since inception of the agreement, as well as all future development and commercialization expenses. In addition, Orion would be eligible to receive milestone payments associated with progress in the development and commercialization of ODM-208 as well as tiered double-digit royalties on sales if the product is approved. Also in July 2022, Merck and Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (Kelun-Biotech) closed a license and collaboration agreement in which Merck gained exclusive worldwide rights for the development, manufacture and commercialization of an investigational antibody drug conjugate (ADC) (MK-1200) for the treatment of solid tumors. Under the terms of the agreement, Merck and Kelun-Biotech will collaborate on the early clinical development of the investigational ADC. Merck made an upfront payment of $35 million, which was recorded in Research and development expenses in the third quarter and first nine months of 2022. Kelun-Biotech is also eligible to receive future contingent milestone payments aggregating up to $82 million in developmental milestones, $334 million in regulatory milestones, and $485 million in sales-based milestones. The agreement also provides for Merck to pay tiered royalties ranging from a mid-single-digit rate to a low-double-digit rate on future net sales. In May 2022, in connection with an existing arrangement, Merck exercised its option to obtain an exclusive license outside of China for the development, manufacture and commercialization of Kelun-Biotech’s trophoblast antigen 2 (TROP2)-targeting ADC programs, including its lead compound, SKB-264 (MK-2870). SKB-264 is currently being evaluated in Phase 2 trials for non-small-cell lung cancer and advanced solid tumors. Under the terms of the agreement, Merck and Kelun-Biotech will collaborate on certain early clinical development plans, including evaluating the potential of SKB-264 as a monotherapy and in combination with Keytruda for advanced solid tumors. Upon option exercise, Merck made a payment of $30 million, which was recorded in Research and development expenses in the first nine months of 2022, and agreed to make additional payments of $30 million upon completion of specified project activities and $25 million upon technology transfer. Merck also agreed to make quarterly payments in 2022 and 2023 aggregating up to $101 million to fund Kelun-Biotech’s ongoing research and development activities. In addition, Kelun-Biotech is eligible to receive future contingent milestone payments (which includes all program compounds) aggregating up to $90 million in developmental milestones, $290 million in first commercial sale milestones, and $780 million in sales-based milestones. The agreement also provides for Merck to pay tiered royalties ranging from a mid-single-digit rate to a low-double-digit rate on future net sales. 2021 Transactions In April 2021, Merck acquired Pandion Therapeutics, Inc. (Pandion), a clinical-stage biotechnology company developing novel therapeutics designed to address the unmet needs of patients living with autoimmune diseases. Pandion is advancing a pipeline of precision immune modulators targeting critical immune control nodes. Total consideration paid of $1.9 billion included $147 million of costs primarily comprised of share-based compensation payments to settle equity awards. The transaction was accounted for as an acquisition of an asset. Merck recorded net assets of $156 million (primarily cash) and Research and development expenses of $1.7 billion in the first nine months of 2021 related to the transaction. There are no future contingent payments associated with the acquisition. In January 2021, Merck entered into an exclusive license and research collaboration agreement with Artiva Biotherapeutics, Inc. (Artiva) to discover, develop and manufacture CAR-NK cells that target certain solid tumors using Artiva’s proprietary platform. Merck and Artiva agreed to engage in up to three different research programs, each covering a collaboration target. Merck has sole responsibility for all development and commercialization activities (including regulatory filing and approval). Under the terms of the agreement, Merck made an upfront payment of $30 million, which was included in Research and development expenses in the first nine months of 2021, for license and other rights for the first two collaboration targets and agreed to make another upfront payment of $15 million for license and other rights for the third collaboration target when it is selected by Merck and accepted by Artiva. In addition, Artiva is eligible to receive future contingent milestone payments (which span all three collaboration targets), aggregating up to $217.5 million in developmental milestones, $570 million in regulatory milestones, and $1.05 billion in sales-based milestones. The agreement also provides for Merck to pay tiered royalties ranging from 7% to 14% on future sales. As part of Merck’s 2020 acquisition of OncoImmune, Merck obtained MK-7110, a therapeutic candidate that was being evaluated for the treatment of patients hospitalized with COVID-19. In 2021, Merck received feedback from the U.S. Food and Drug Administration (FDA) that additional data would be needed to support a potential Emergency Use Authorization application and therefore the Company did not expect MK-7110 would become available until the first half of 2022. Given this timeline and the technical, clinical and regulatory uncertainties, the availability of a number of medicines for patients hospitalized with COVID-19, and the need to concentrate Merck’s resources on accelerating the development and manufacture of the most viable therapeutics and vaccines, Merck decided to discontinue development of MK-7110 for the treatment of COVID-19. Due to the discontinuation, the Company recorded charges of $207 million in the first nine months of 2021, which are reflected in Cost of sales and relate to fixed assets and materials written off, as well as the recognition of liabilities for purchase commitments.