XML 58 R65.htm IDEA: XBRL DOCUMENT v2.4.0.8
Equity (Details Textual) (USD $)
3 Months Ended 6 Months Ended
Jun. 30, 2014
Jun. 30, 2013
Jun. 30, 2014
Jun. 30, 2013
Feb. 28, 2011
Equity (Textual) [Abstract]          
Equity increase during the period     $ 944,400,000    
Net income attributable to Biogen Idec Inc 714,506,000 490,670,000 1,194,462,000 917,419,000  
Adjustments to additional paid in capital, share-based compensation and exercise of stock options     82,400,000    
Common stock shares authorized for repurchase 3,000,000   3,000,000   20,000,000.0
Repurchase of common stock, shares     1,200,000 300,000  
Purchase of treasury stock, value     $ 336,905,000 $ 41,023,000