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Other Consolidated Financial Statement Detail (Details Textual) (USD $)
12 Months Ended 3 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Mar. 31, 2012
Dec. 31, 2012
Mar. 08, 2012
Business Acquisition          
Increase to goodwill $ 527,300,000us-gaap_GoodwillAcquiredDuringPeriod $ 35,700,000us-gaap_GoodwillAcquiredDuringPeriod      
Total purchase price allocated to goodwill 1,760,249,000us-gaap_Goodwill 1,232,916,000us-gaap_Goodwill   1,201,300,000us-gaap_Goodwill  
Contingent consideration obligation 0us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchases 0us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchases      
Cambridge Leases          
Business Acquisition          
Derecognition of construction in progress assets   161,500,000biib_DerecognitionOfConstructionInProgressAssets
/ biib_FacilityLocationAxis
= biib_CambridgeLeasesMember
     
Stromedix, Inc.          
Business Acquisition          
Total purchase price allocated to IPR&D         219,200,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets
/ us-gaap_BusinessAcquisitionAxis
= biib_StromedixMember
Total purchase price allocated to goodwill         48,200,000us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= biib_StromedixMember
Contingent consideration obligation     122,200,000us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchases
/ us-gaap_BusinessAcquisitionAxis
= biib_StromedixMember
   
Four billion | Fumapharm AG          
Business Acquisition          
Cumulative sales level 4,000,000,000biib_CumulativeSalesLevel
/ us-gaap_BusinessAcquisitionAxis
= biib_FumapharmAgMember
/ biib_CumulativeSalesLevelAxis
= biib_FourbillionMember
       
TECFIDERA | Fumapharm AG          
Business Acquisition          
Increase to goodwill 600,000,000us-gaap_GoodwillAcquiredDuringPeriod
/ us-gaap_BusinessAcquisitionAxis
= biib_FumapharmAgMember
/ us-gaap_ProductOrServiceAxis
= biib_TecfideraMember
       
TECFIDERA | Four billion | Fumapharm AG          
Business Acquisition          
Increase to goodwill $ 250,000,000us-gaap_GoodwillAcquiredDuringPeriod
/ us-gaap_BusinessAcquisitionAxis
= biib_FumapharmAgMember
/ biib_CumulativeSalesLevelAxis
= biib_FourbillionMember
/ us-gaap_ProductOrServiceAxis
= biib_TecfideraMember