XML 117 R35.htm IDEA: XBRL DOCUMENT
v3.22.4

Summary of Significant Accounting Policies (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2022
Accounting Policies [Abstract] |
Property, plant and equipment estimated useful lives | We generally depreciate or amortize the cost of our property, plant and equipment using the straight-line method over the estimated useful lives of the respective assets, which are summarized as follows:
Asset Category | Useful Lives
Land | Not depreciated
Buildings | 15 to 40 years
Leasehold Improvements | Lesser of the useful life or the term of the respective lease
Furniture and Fixtures | 5 to 7 years
Machinery and Equipment | 5 to 20 years
Computer Software and Hardware | 3 to 5 years

X
- Definition Schedule of property plant and equipment useful lives. + References No definition available. + Details
Name: | biib_ScheduleOfPropertyPlantAndEquipmentUsefulLivesTableTextBlock
Namespace Prefix: | biib_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

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