XML 100 R68.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Leases (Details Textual) - USD ($) $ in Millions | 1 Months Ended |
--- | --- | ---
Sep. 30, 2022 | Dec. 31, 2021
Operating Leased Assets [Line Items] |  |
Operating lease assets | $ 424.5 | $ 375.4
Right-of-use assets derecognized | 47.4 |
Lease liabilities derecognized | 52.7 |
Gain due to lease termination | $ 5.3 |
125 Broadway Building |  |
Operating Leased Assets [Line Items] |  |
Lease term | 5 years 6 months |
Operating lease assets | $ 168.2 |
Operating lease liabilities | $ 168.2 |

X
- Definition Gain (Loss) On Restructuring Charges + References No definition available. + Details
Name: | biib_GainLossOnRestructuringCharges
Namespace Prefix: | biib_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Operating Lease, Liability, Derecognized + References No definition available. + Details
Name: | biib_OperatingLeaseLiabilityDerecognized
Namespace Prefix: | biib_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Operating Lease, Right-Of-Use Asset, Derecognized + References No definition available. + Details
Name: | biib_OperatingLeaseRightOfUseAssetDerecognized
Namespace Prefix: | biib_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918673-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseTermOfContract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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 No definition available. + Details
Name: | us-gaap_OperatingLeasedAssetsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |