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Earnings per Share (Tables)

3 Months Ended

Mar. 31, 2021

Earnings Per Share [Abstract]

Basic and diluted earnings per share

Basic and diluted earnings per share are calculated as follows:

						For the Three Months Ended March 31,
(In millions)						2021						2020
Numerator:
Net income attributable to Biogen Inc.						$	410.2					$	1,399.1
Denominator:
Weighted average number of common shares outstanding						151.9						172.8
Effect of dilutive securities:
Time-vested restricted stock units						0.2						0.1
Market stock units						0.1						0.1
Performance stock units settled in stock						0.1						0.1
Dilutive potential common shares						0.4						0.3
Shares used in calculating diluted earnings per share						152.3						173.1

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- References

No definition available.

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- Definition

Tabular disclosure of an entity's basic and diluted earnings per share calculations, including a reconciliation of numerators and denominators of the basic and diluted per-share computations for income from continuing operations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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