Created by potrace 1.16, written by Peter Selinger 2001-2019beatandraise.com

BIOGEN INC.

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 2.2.0.7 false Document and Entity Information (USD $) 00 - Document - Document and Entity Information true false false false 1 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ false 2 false false Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 false 3 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ 2 0 biib_DocumentAndEntityInformationAbstract biib false na duration Document and Entity Information. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:stringItemType string Document and Entity Information. false 3 1 dei_EntityRegistrantName dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 BIOGEN IDEC INC. BIOGEN IDEC INC. false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:normalizedStringItemType normalizedstring The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false 4 1 dei_EntityCentralIndexKey dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 0000875045 0000875045 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false us-types:centralIndexKeyItemType na A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false 5 1 dei_DocumentType dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 10-Q 10-Q false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false us-types:SECReportItemType na The type of document being provided (such as 10-K, 10-Q, N-1A, etc). The document type should be limited to the same value as the supporting SEC submission type. The acceptable values are as follows: S-1, S-3, S-4, S-11, F-1, F-3, F-4, F-9, F-10, 6-K, 8-K, 10, 10-K, 10-Q, 20-F, 40-F, N-1A, 485BPOS, NCSR, N-Q, and Other. No authoritative reference available. false 6 1 dei_DocumentPeriodEndDate dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 2010-09-30 2010-09-30 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:dateItemType date The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements this will be the filing date. The format of the date is CCYY-MM-DD. No authoritative reference available. false 7 1 dei_AmendmentFlag dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:booleanItemType na If the value is true, then the document as an amendment to previously-filed/accepted document. No authoritative reference available. false 8 1 dei_DocumentFiscalYearFocus dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 2010 2010 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:gYearItemType positiveinteger This is focus fiscal year of the document report in CCYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006. No authoritative reference available. false 9 1 dei_DocumentFiscalPeriodFocus dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 Q3 Q3 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false us-types:fiscalPeriodItemType na This is focus fiscal period of the document report. For a first quarter 2006 quarterly report, which may also provide financial information from prior periods, the first fiscal quarter should be given as the fiscal period focus. Values: FY, Q1, Q2, Q3, Q4, H1, H2, M9, T1, T2, T3, M8, CY. No authoritative reference available. false 10 1 dei_CurrentFiscalYearEndDate dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 --12-31 --12-31 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false xbrli:gMonthDayItemType monthday End date of current fiscal year in the format --MM-DD. No authoritative reference available. false 11 1 dei_EntityWellKnownSeasonedIssuer dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 Yes Yes false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false us-types:yesNoItemType na Indicate "Yes" or "No" if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Is used on Form Type: 10-K, 10-Q, 8-K, 20-F, 6-K, 10-K/A, 10-Q/A, 20-F/A, 6-K/A, N-CSR, N-Q, N-1A. No authoritative reference available. false 12 1 dei_EntityVoluntaryFilers dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 No No false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false us-types:yesNoItemType na Indicate "Yes" or "No" if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. No authoritative reference available. false 13 1 dei_EntityCurrentReportingStatus dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 Yes Yes false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false us-types:yesNoItemType na Indicate "Yes" or "No" whether registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that registrants were required to file such reports), and (2) have been subject to such filing requirements for the past 90 days. This information should be based on the registrant's current or most recent filing containing the related disclosure. No authoritative reference available. false 14 1 dei_EntityFilerCategory dei false na duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 Large Accelerated Filer Large Accelerated Filer false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false us-types:filerCategoryItemType na Indicate whether the registrant is one of the following: (1) Large Accelerated Filer, (2) Accelerated Filer, (3) Non-accelerated Filer, or (4) Smaller Reporting Company. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure. No authoritative reference available. false 15 1 dei_EntityPublicFloat dei false credit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 true true false false 11688813825.2 11688813825.2 false false false xbrli:monetaryItemType monetary State aggregate market value of voting and non-voting common equity held by non-affiliates computed by reference to price at which the common equity was last sold, or average bid and asked price of such common equity, as of the last business day of registrant's most recently completed second fiscal quarter. The public float should be reported on the cover page of the registrants form 10K. No authoritative reference available. false 16 1 dei_EntityCommonStockSharesOutstanding dei false na instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 238302269 238302269 false false false 3 false false false false 0 0 false false false xbrli:sharesItemType shares Indicate number of shares outstanding of each of registrant's classes of common stock, as of latest practicable date. Where multiple classes exist define each class by adding class of stock items such as Common Class A [Member], Common Class B [Member] onto the Instrument [Domain] of the Entity Listings, Instrument No authoritative reference available. false 3 15 false NoRounding NoRounding UnKnown false true