2.2.0.7falseShareholder's Equity0210 - Disclosure - Shareholder's Equitytruefalsefalsefalse1USDfalsefalseUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0PureStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDEPSDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0$20us-gaap_StockholdersEquityNoteAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalsefalse00falsefalsefalsexbrli:stringItemTypestringNo definition available.false31us-gaap_StockholdersEquityNoteDisclosureTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabelfalse1falsefalsefalsefalse00<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
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<b><font style="font-family: 'Times New Roman', Times">10.  </font></b>
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<b><font style="font-family: 'Times New Roman', Times">Shareholders’
Equity</font></b>
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Shareholders’ equity as of September 30, 2010,
decreased $1,191.7 million compared to December 31,
2009.
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For the nine months ended September 30, 2010, we
repurchased approximately 40.3 million shares at a cost of
approximately $2.1 billion under our 2010 and 2009 stock
repurchase authorizations. We retired all of these shares as
they were acquired. In connection with this retirement, in
accordance with our policy, we recorded a reduction in
additional
<font style="white-space: nowrap">paid-in-capital</font>
by the same amount. Our 2010 and 2009 stock repurchase programs
were completed during the third and first quarters of 2010,
respectively.
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This decline in shareholders’ equity was offset by net
income attributable to Biogen Idec Inc. of $765.0 million,
and the increase to additional paid-in capital resulting from
the amortization of expense associated with our share-based
compensation programs of $137.1 million.
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<!-- Begin Block Tagged Notefalsefalsefalseus-types:textBlockItemTypetextblockDisclosures related to accounts comprising shareholders' equity, including other comprehensive income. Includes: (1) balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings; (2) accumulated balance for each classification of other comprehensive income and total amount of comprehensive income; (3) amount and nature of changes in separate accounts, including the number of shares authorized and outstanding, number of shares issued upon exercise and conversion, and for other comprehensive income, the adjustments for reclassifications to net income; (4) rights and privileges of each class of stock authorized; (5) basis of treasury stock, if other than cost, and amounts paid and accounting treatment for treasury stock purchased significantly in excess of market; (6) dividends paid or payable per share and in the aggregate for each class of stock for each period presented; (7) dividend restrictions and accumulated preferred dividends in arrears (in aggregate and per share amount); (8) retained earnings appropriations or restrictions, such as dividend restrictions; (9) impact of change in accounting principle, initial adoption of new accounting principle and correction of an error in previously issued financial statements; (10) shares held in trust for Employee Stock Ownership Plan (ESOP); (11) deferred compensation related to issuance of capital stock; (12) note received for issuance of stock; (13) unamortized discount on shares; (14) description, terms and number of warrants or rights outstanding; (15) shares under subscription and subscription receivables; effective date of new retained earnings after quasi-reorganization and deficit eliminated by quasi-reorganization and, for a period of at least ten years after the effective date, the point in time from which the new retained dates; and (16) retroactive effective of subsequent change in capital structure.Reference 1: http://www.xbrl.org/2003/role/presentationRef
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