XML 120 R101.htm IDEA: XBRL DOCUMENT
v3.25.1

Collaborative and Other Relationships - Stoke Therapeutics, Inc. (Details) - USD ($) $ in Millions | 1 Months Ended |
--- | --- | ---
Feb. 28, 2025 | Mar. 31, 2025
Zorevunersen |  |
Collaborative arrangements and non-collaborative arrangement transactions |  |
Percentage of future development costs | 30.00% |
Stoke Therapeutics Inc |  |
Collaborative arrangements and non-collaborative arrangement transactions |  |
Upfront And Milestone Payments Made To Collaborative Partner | $ 165.0 |
Stoke Therapeutics Inc | Zorevunersen |  |
Collaborative arrangements and non-collaborative arrangement transactions |  |
Percentage of future development costs | 70.00% |
Stoke Therapeutics Inc | Milestone Payment, Developmental |  |
Collaborative arrangements and non-collaborative arrangement transactions |  |
Estimated additional payments upon achievement of development and commercial milestones |  | $ 50.0
Stoke Therapeutics Inc | Milestone Payment, Commercial |  |
Collaborative arrangements and non-collaborative arrangement transactions |  |
Estimated additional payments upon achievement of development and commercial milestones |  | $ 335.0

X
- Definition Estimated additional payments upon achievement of development and commercial milestones. + References No definition available. + Details
Name: | biib_EstimatedAdditionalPaymentsUponAchievementOfDevelopmentAndCommercialMilestones
Namespace Prefix: | biib_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Percentage Of Future Development Costs + References No definition available. + Details
Name: | biib_PercentageOfFutureDevelopmentCosts
Namespace Prefix: | biib_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total upfront and milestone payments made to collaborative partner. + References No definition available. + Details
Name: | biib_UpfrontAndMilestonePaymentsMadeToCollaborativePartner
Namespace Prefix: | biib_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 808 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479402/808-10-50-1 + Details
Name: | us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_ProductOrServiceAxis=biib_ZorevunersenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=biib_StokeTherapeuticsIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ContingentConsiderationByTypeAxis=biib_MilestonePaymentDevelopmentalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ContingentConsiderationByTypeAxis=biib_MilestonePaymentCommercialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |