XML 46 R27.htm IDEA: XBRL DOCUMENT
v3.25.1

Investments in Variable Interest Entities | 3 Months Ended
--- | ---
Mar. 31, 2025
Investments in Variable Interest Entities [Abstract] |
Investments in Variable Interest Entities |
Note 20: | Investments in Variable Interest Entities
Unconsolidated Variable Interest Entities We have relationships with various variable interest entities that we do not consolidate as we lack the power to direct the activities that significantly impact the economic success of these entities. These relationships include investments in certain biotechnology companies and research collaboration agreements. As of March 31, 2025 and December 31, 2024, the carrying value of our investments in certain biotechnology companies representing potential unconsolidated variable interest entities totaled $19.3 million and $23.6 million, respectively. Our maximum exposure to loss related to these variable interest entities is limited to the carrying value of our investments. We have also entered into research collaboration agreements with certain variable interest entities where we are required to fund certain development activities. These development activities are included in research and development expense in our condensed consolidated statements of income as they are incurred. We have provided no financing to these variable interest entities other than previous contractually required amounts. For additional information on our investments in variable interest entities, please read Note 20, Investments in Variable Interest Entities, to our consolidated financial statements included in our 2024 Form 10-K.

X
- Definition Investments In Variable Interest Entities. + References No definition available. + Details
Name: | biib_InvestmentsInVariableInterestEntitiesAbstract
Namespace Prefix: | biib_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for a variable interest entity (VIE), including but not limited to, judgments and assumptions in determining whether to consolidate and in identifying the primary beneficiary, gain (loss) recognized on the initial consolidation of the VIE, terms of arrangements, amounts and classification of the VIE's assets and liabilities, and the entity's maximum exposure to loss. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 810 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org/810/tableOfContent + Details
Name: | us-gaap_VariableInterestEntityDisclosureTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration