XML 81 R55.htm IDEA: XBRL DOCUMENT
v3.24.2.u1

Revenues - Revenues by product (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | $ 2,464.9 | $ 2,456.0 | $ 4,755.4 | $ 4,919.0
Product, net |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 1,899.6 | 1,845.8 | 3,611.5 | 3,609.1
Product, net | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 846.7 | 801.0 | 1,592.8 | 1,502.4
Product, net | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 1,052.9 | 1,044.8 | 2,018.7 | 2,106.7
MS Product Revenues |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 1,149.8 | 1,209.3 | 2,225.7 | 2,334.5
MS Product Revenues | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 582.4 | 636.7 | 1,085.6 | 1,182.8
MS Product Revenues | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 567.4 | 572.6 | 1,140.1 | 1,151.7
Fumarate |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 418.0 | 400.4 | 799.8 | 783.1
Fumarate | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 188.3 | 196.8 | 337.9 | 365.0
Fumarate | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 229.7 | 203.6 | 461.9 | 418.1
TECFIDERA |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 252.2 | 254.2 | 506.5 | 528.7
TECFIDERA | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 44.1 | 66.5 | 87.8 | 141.2
TECFIDERA | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 208.1 | 187.7 | 418.7 | 387.5
VUMERITY |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 165.8 | 146.2 | 293.3 | 254.4
VUMERITY | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 144.2 | 130.3 | 250.1 | 223.8
VUMERITY | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 21.6 | 15.9 | 43.2 | 30.6
Interferon |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 250.9 | 302.4 | 494.5 | 548.0
Interferon | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 145.4 | 180.0 | 285.2 | 312.5
Interferon | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 105.5 | 122.4 | 209.3 | 235.5
AVONEX |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 182.8 | 220.3 | 361.3 | 392.7
AVONEX | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 117.2 | 145.9 | 228.4 | 248.5
AVONEX | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 65.6 | 74.4 | 132.9 | 144.2
PLEGRIDY |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 68.1 | 82.1 | 133.2 | 155.3
PLEGRIDY | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 28.2 | 34.1 | 56.8 | 64.0
PLEGRIDY | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 39.9 | 48.0 | 76.4 | 91.3
TYSABRI |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 462.2 | 483.1 | 893.5 | 955.9
TYSABRI | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 248.7 | 259.9 | 462.5 | 505.3
TYSABRI | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 213.5 | 223.2 | 431.0 | 450.6
FAMPYRA |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 18.7 | 23.4 | 37.9 | 47.5
FAMPYRA | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 0.0 | 0.0 | 0.0 | 0.0
FAMPYRA | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 18.7 | 23.4 | 37.9 | 47.5
Rare Disease Product Revenue |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 534.1 | 438.0 | 958.0 | 881.3
Rare Disease Product Revenue | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 237.5 | 156.7 | 463.4 | 303.4
Rare Disease Product Revenue | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 296.6 | 281.3 | 494.6 | 577.9
QALSODY |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 5.0 |  | 9.6 | 0.9
QALSODY | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 4.6 |  | 9.0 | 0.9
QALSODY | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 0.4 |  | 0.6 | 0.0
SPINRAZA |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 429.1 | 437.1 | 770.4 | 880.4
SPINRAZA | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 157.3 | 155.8 | 305.8 | 302.5
SPINRAZA | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 271.8 | 281.3 | 464.6 | 577.9
Completed technology for SKYCLARYS (U.S.) |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 100.0 |  | 178.0 | 0.0
Completed technology for SKYCLARYS (U.S.) | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 75.6 |  | 148.6 | 0.0
Completed technology for SKYCLARYS (U.S.) | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 24.4 |  | 29.4 | 0.0
Biosimilars |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 198.1 | 195.1 | 395.0 | 387.5
Biosimilars | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 11.1 | 7.0 | 14.8 | 15.2
Biosimilars | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 187.0 | 188.1 | 380.2 | 372.3
BENEPALI |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 117.3 | 109.2 | 236.0 | 218.2
BENEPALI | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 0.0 | 0.0 | 0.0 | 0.0
BENEPALI | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 117.3 | 109.2 | 236.0 | 218.2
IMRALDI |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 53.2 | 58.8 | 108.0 | 113.2
IMRALDI | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 0.0 | 0.0 | 0.0 | 0.0
IMRALDI | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 53.2 | 58.8 | 108.0 | 113.2
FLIXABI |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 13.1 | 20.1 | 30.9 | 40.5
FLIXABI | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 0.0 | 0.0 | 0.0 | 0.0
FLIXABI | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 13.1 | 20.1 | 30.9 | 40.5
BYOOVIZ |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 13.7 | 7.0 | 19.3 | 15.6
BYOOVIZ | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 10.3 | 7.0 | 14.0 | 15.2
BYOOVIZ | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 3.4 | 0.0 | 5.3 | 0.4
TOFIDENCE |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 0.8 | 0.0 | 0.8 | 0.0
TOFIDENCE | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 0.8 | 0.0 | 0.8 | 0.0
TOFIDENCE | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 0.0 | 0.0 | 0.0 | 0.0
Other |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 17.6 | 3.4 | 32.8 | 5.8
Other | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 15.7 | 0.6 | 29.0 | 1.0
Other | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 1.9 | 2.8 | 3.8 | 4.8
ZURZUVAE |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 14.9 | 0.0 | 27.3 | 0.0
ZURZUVAE | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 14.9 | 0.0 | 27.3 | 0.0
ZURZUVAE | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 0.0 | 0.0 | 0.0 | 0.0
FUMADERM And ADUHELM |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 2.7 | 3.4 | 5.5 | 5.8
FUMADERM And ADUHELM | U.S. |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | 0.8 | 0.6 | 1.7 | 1.0
FUMADERM And ADUHELM | Rest of World |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Product revenues | $ 1.9 | $ 2.8 | $ 3.8 | $ 4.8

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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479806/606-10-50-5 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 91 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479777/606-10-55-91 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 91 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479777/606-10-55-91 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 91 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479777/606-10-55-91 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 91 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479777/606-10-55-91 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 91 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479777/606-10-55-91 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 91 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479777/606-10-55-91 Reference 8: http://www.xbrl.org/2003/role/exampleRef -Topic 606 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 91 -Subparagraph (g) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479777/606-10-55-91 + Details
Name: | us-gaap_DisaggregationOfRevenueLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 48 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482785/280-10-55-48 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 41 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-41 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 270 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482964/270-10-50-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 32 -Subparagraph (ee) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-32 Reference 5: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 32 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-32 Reference 6: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 32 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-32 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(g)(1)(ii)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481687/323-10-50-3 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 28 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-28 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(4)(i)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A Reference 11: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(4)(ii)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(4)(iii)(A)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(4)(iv)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(5)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1A Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(4)(i)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(4)(iii)(A)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(4)(iii)(B)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(4)(iv)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(5)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480097/470-10-S99-1B Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 30 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-30 Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 42 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-42 Reference 22: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 22 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-22 Reference 23: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 40 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-40 Reference 24: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 22 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-22 Reference 25: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-05(b)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477314/942-235-S99-1 Reference 26: http://www.xbrl.org/2003/role/disclosureRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 + Details
Name: | us-gaap_Revenues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | srt_ProductOrServiceAxis=us-gaap_ProductMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_US
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=us-gaap_NonUsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_MSProductRevenuesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_FumarateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_TECFIDERAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_VUMERITYMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_InterferonMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_AVONEXMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_PLEGRIDYMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_TysabriProductMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_FAMPYRAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_RareDiseaseProductRevenueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_QALSODYMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_SPINRAZAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_SKYCLARYSMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_BiosimilarsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_BENEPALIMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_IMRALDIMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_FLIXABIMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_BYOOVIZMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_TOFIDENCEMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_OtherProductsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_ZURZUVAEMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=biib_FUMADERMAndADUHELMMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |