<SEC-DOCUMENT>0001193125-24-217633-index.html : 20240912
<SEC-HEADER>0001193125-24-217633.hdr.sgml : 20240912
<ACCEPTANCE-DATETIME>20240912073132
ACCESSION NUMBER:		0001193125-24-217633
CONFORMED SUBMISSION TYPE:	8-K
PUBLIC DOCUMENT COUNT:		14
CONFORMED PERIOD OF REPORT:	20240911
ITEM INFORMATION:		Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers
FILED AS OF DATE:		20240912
DATE AS OF CHANGE:		20240912

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			BIOGEN INC.
		CENTRAL INDEX KEY:			0000875045
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				330112644
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		8-K
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19311
		FILM NUMBER:		241293917

	BUSINESS ADDRESS:	
		STREET 1:		225 BINNEY STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142
		BUSINESS PHONE:		7814642000

	MAIL ADDRESS:	
		STREET 1:		225 BINNEY STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	BIOGEN IDEC INC.
		DATE OF NAME CHANGE:	20070427

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	BIOGEN IDEC INC
		DATE OF NAME CHANGE:	20031112

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	IDEC PHARMACEUTICALS CORP / DE
		DATE OF NAME CHANGE:	19970530
</SEC-HEADER>
<DOCUMENT>
<TYPE>8-K
<SEQUENCE>1
<FILENAME>d896502d8k.htm
<DESCRIPTION>8-K
<TEXT>
Document 1 - file: d896502d8k.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-101.SCH
<SEQUENCE>2
<FILENAME>biib-20240911.xsd
<DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA
<TEXT>
Document 2 - file: biib-20240911.xsd

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-101.LAB
<SEQUENCE>3
<FILENAME>biib-20240911_lab.xml
<DESCRIPTION>XBRL TAXONOMY EXTENSION LABEL LINKBASE
<TEXT>
Document 3 - file: biib-20240911_lab.xml

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-101.PRE
<SEQUENCE>4
<FILENAME>biib-20240911_pre.xml
<DESCRIPTION>XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE
<TEXT>
Document 4 - file: biib-20240911_pre.xml

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>5
<FILENAME>g896502g07w87.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 5 - file: g896502g07w87.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>7
<FILENAME>R1.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 7 - file: R1.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EXCEL
<SEQUENCE>8
<FILENAME>Financial_Report.xlsx
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 8 - file: Financial_Report.xlsx

</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>9
<FILENAME>Show.js
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 9 - file: Show.js

</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>10
<FILENAME>report.css
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 10 - file: report.css

</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>12
<FILENAME>FilingSummary.xml
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 12 - file: FilingSummary.html

Document 12 - RAW XML: FilingSummary.xml

</DOCUMENT>
<DOCUMENT>
<TYPE>JSON
<SEQUENCE>14
<FILENAME>MetaLinks.json
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 14 - file: MetaLinks.json

</DOCUMENT>
<DOCUMENT>
<TYPE>ZIP
<SEQUENCE>15
<FILENAME>0001193125-24-217633-xbrl.zip
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 15 - file: 0001193125-24-217633-xbrl.zip

</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>16
<FILENAME>d896502d8k_htm.xml
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 16 - file: d896502d8k_htm.html

Document 16 - RAW XML: d896502d8k_htm.xml

</DOCUMENT>
</SEC-DOCUMENT>