Collaboration Agreements and Research and Development Funding Arrangements	12 Months Ended
	Dec. 31, 2025
Research and Development [Abstract]
Collaboration Agreements and Research and Development Funding Arrangements	5. Collaboration Agreements and Research and Development Funding Arrangement Merck – Personalized mRNA Cancer Vaccines (Intismeran Autogene) In June 2016, we entered into a Collaboration and License Agreement, which was subsequently amended in 2018, with Merck for the development and commercialization of personalized mRNA cancer vaccines (PCV), also known as Individualized Neoantigen Therapy (INT), which has been assigned the generic name intismeran autogene. This agreement was subsequently amended in 2018. Under the PCV Agreement, we received an upfront payment of $200 million from Merck and we were responsible for designing and researching intismeran, providing manufacturing capacity and manufacturing intismeran and conducting Phase 1 and Phase 2 clinical trials for intismeran, alone and in combination with KEYTRUDA (pembrolizumab), Merck’s anti-PD-1 therapy, all in accordance with an agreed upon development plan and budget. We concluded that the collaboration arrangement was governed by the revenue recognition standard ASC 606. In September 2022, Merck exercised its option for intismeran, including mRNA-4157, under the terms of the agreement and in October 2022 paid us an option exercise fee of $250 million. Following this exercise, the Merck Participation Term commenced, under which we and Merck collaborate on development and potential commercialization of PCV, with costs and any profits or losses generally shared equally on a worldwide basis, subject to certain exceptions as outlined in the agreement. During the development phase, we are primarily responsible for process development and the manufacture of intismeran materials, while Merck generally leads clinical trials. We concluded that the collaboration arrangement under the Merck Participation Term is within the scope of ASC 808. For the years ended December 31, 2025, 2024 and 2023, we recognized expenses, net of Merck's reimbursements, of $407 million, $390 million, and $184 million, respectively, related to the PCV collaboration under the Merck Participation Term. Additionally, the net cost recovery for capital expenditures during the same periods were $24 million, $109 million, and $102 million, respectively, which were applied to reduce the capitalized cost of the assets. Development and Commercialization Funding Arrangement with Blackstone Life Sciences (Blackstone) In March 2024, we entered into a development and commercialization funding arrangement with Blackstone, under which Blackstone has committed to providing up to $750 million in funding to us. This funding supports the development of our investigational mRNA-based influenza vaccine. Contingent upon regulatory approval in the U.S. and only if the approval is dependent on data from the funded activities, Blackstone will be entitled to receive low single-digit percentage royalties and up to $750 million in sales milestone payments. These payments are based on net sales of our future influenza and combination vaccines, with sales milestone payments contingent upon achieving specified cumulative net sales targets. Given the substantive transfer of financial risk to Blackstone, we account for this arrangement as an obligation to conduct research and development activities. The funding is recognized as a reduction to the expenses of our mRNA-based influenza program. This reduction is recognized proportionally as the related costs are incurred, based on an input method. For the year ended December 31, 2025 and 2024, we recorded research and development expense reductions of $340 million and $267 million, respectively. As of December 31, 2025 and 2024, we had a research and development funding liability of $43 million and $58 million, respectively, related to the advance funding received from Blackstone. Vertex – Strategic Alliance in Cystic Fibrosis In July 2016, we entered into a Strategic Collaboration and License Agreement (Vertex Agreement), with Vertex Pharmaceuticals Incorporated, and Vertex Pharmaceuticals (Europe) Limited, together, Vertex. The Vertex Agreement, which was amended in July 2019 (2019 Vertex Amendment), is aimed at the discovery and development of potential mRNA medicines for the treatment of cystic fibrosis (CF) by enabling cells in the lungs of people with CF to produce functional cystic fibrosis transmembrane conductance regulator (CFTR) proteins. Pursuant to the Vertex Agreement, we lead discovery efforts during an initial research period, leveraging our platform technology and mRNA delivery expertise along with Vertex’s scientific experience in CF biology and the functional understanding of CFTR. Vertex is responsible for conducting development and commercialization activities for candidates and products that arise from the strategic alliance, including the costs associated with such activities. Subject to customary “back-up” supply rights granted to Vertex, we exclusively manufacture (or have manufactured) mRNA for preclinical, clinical and commercialization purposes. This collaboration arrangement is accounted for under ASC 606 and currently ongoing. Immatics – Strategic Multi-Platform Collaboration to Develop Oncology Therapeutics In September 2023, we entered into a strategic collaboration with Immatics to jointly discover and develop T cell-redirecting cancer immunotherapies. Upon effectiveness of the agreement in October 2023, we made an upfront payment of $120 million, recognized as research and development expense. Immatics is also eligible for research funding, milestone payments, tiered royalties on global net sales of TCER® products and certain vaccine products that are commercialized under the agreement. Additionally, Immatics has an option to enter into a global profit and loss share arrangement for the most advanced TCER®. In addition to the collaborative arrangements mentioned above, we have other collaborative and licensing arrangements that we do not consider to be individually significant to our business at this time. Pursuant to these agreements, we may be required to make upfront payments and payments upon achievement of various development, regulatory and commercial milestones, which in the aggregate could be significant. Future milestone payments, if any, will be reflected in our consolidated financial statements when the corresponding events become probable. In addition, we may be required to pay significant royalties on future sales if products related to these arrangements are commercialized.