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Biogen share of co-promotion profits or losses

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- Definition

License Fee

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- Definition

Percentage of royalties as per collaboration.

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- 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.

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Amount of increase (decrease) in carrying value of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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- Definition

Amount, after sales adjustments, returns, allowances, and discounts, of revenue classified as other.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(a),(d))
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The costs incurred in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, excluding in-process research and development acquired in a business combination consummated during the period. Excludes software research and development, which has a separate concept.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 730
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6420194&loc=d3e21568-108373

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- Definition

Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Collaborative and Other Relationships Collaborative and Other Relationships - Collaborations (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Mar. 31, 2016
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development	$ 423.4			$ 437.3
Other	90.0			87.9
Product, net	2,380.1			$ 2,309.4
Bristol-Myers Squibb
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development	300.0
Additional milestone payments	410.0
iPerian
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Additional milestone payments	$ 550.0
AbbVie
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Biogen share of co-promotion profits or losses	50.00%
AbbVie \| U.S.
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Other	$ 5.9
Ionis Pharmaceuticals [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License Fee			$ 75.0
Ionis Pharmaceuticals [Member] \| SPINRAZA
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Additional milestone payments	90.0
Ionis Pharmaceuticals [Member] \| SPINRAZA \| U.S.
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Product, net	46.4
Ionis Pharmaceuticals [Member] \| SPINRAZA \| Rest of world
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Product, net	$ 1.0
Acquired and in-licensed rights and patents \| SPINRAZA
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Increase in acquired and in-licensed rights and patents		$ 60.0
Minimum \| Ionis Pharmaceuticals [Member] \| SPINRAZA
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty payments per the collaboration	11.00%
Maximum \| Ionis Pharmaceuticals [Member] \| SPINRAZA
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty payments per the collaboration	15.00%
FY 2017 \| iPerian
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Additional milestone payments	$ 60.0