v2.4.0.6
Acquisitions (Narrative) (Details) (USD $)
3 Months Ended 12 Months Ended 0 Months Ended 3 Months Ended 0 Months Ended 3 Months Ended 0 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Dec. 31, 2011
Arresto Biosciences, Inc. [Member]
Mar. 31, 2011
Arresto Biosciences, Inc. [Member]
Jan. 14, 2011
Arresto Biosciences, Inc. [Member]
Dec. 31, 2010
Arresto Biosciences, Inc. [Member]
Dec. 31, 2011
Calistoga Pharmaceuticals, Inc. [Member]
Apr. 02, 2011
Calistoga Pharmaceuticals, Inc. [Member]
Mar. 31, 2011
Calistoga Pharmaceuticals, Inc. [Member]
Feb. 28, 2011
Calistoga Pharmaceuticals, Inc. [Member]
Jan. 14, 2011
Calistoga Pharmaceuticals, Inc. [Member]
Jul. 08, 2010
CGI Pharmaceuticals, Inc. [Member]
Dec. 31, 2011
CGI Pharmaceuticals, Inc. [Member]
Jun. 30, 2010
CGI Pharmaceuticals, Inc. [Member]
Apr. 15, 2009
CV Therapeutics, Inc. [Member]
Mar. 31, 2011
CV Therapeutics, Inc. [Member]
Dec. 31, 2010
CV Therapeutics, Inc. [Member]
Apr. 15, 2009
Ranexa [Member]
Apr. 15, 2009
Lexiscan [Member]
Apr. 15, 2009
Marketed Products [Member]
CV Therapeutics, Inc. [Member]
Apr. 15, 2009
Intangible Assets - IPR&D [Member]
CV Therapeutics, Inc. [Member]
Apr. 15, 2009
2.75% Senior Subordinated Convertible Notes Due 2012 [Member]
CV Therapeutics, Inc. [Member]
Apr. 15, 2009
3.25% Senior Subordinated Convertible Notes due 2013
CV Therapeutics, Inc. [Member]
Apr. 15, 2009
2.0% Senior Subordinated Convertible Debentures Due 2023 [Member]
CV Therapeutics, Inc. [Member]
Apr. 15, 2009
GS-9667 [Member]
CV Therapeutics, Inc. [Member]
Business Acquisition [Line Items]                                                        
Total cash paid for acquisition             $ 221,700,000             $ 373,700,000     $ 91,000,000 $ 1,380,000,000                    
Aggregate consideration transferred for the acquisition                 225,000,000       375,000,000   102,100,000     1,392,558,000                    
Acquisition-date fair value of total consideration transferred to acquire company               227,100,000       484,300,000                                
Contingent consideration paid             5,400,000             110,600,000 11,100,000                          
Acquisition-date fair value of intangible assets             117,000,000             149,200,000           2,900,000                
Present value discount rate               16.00%       11.00%     18.00%                          
Goodwill resulting from acquisition           134,482,000   134,482,000   336,951,000 336,951,000       70,111,000     341,910,000                    
Potential payments based on the achievement of milestones                         225,000,000                              
Maximum consideration of acquisition                             120,000,000                          
Maximum value of contingent consideration                             29,000,000                          
Fair value of intangible assets related to IPR&D                                               138,900,000       93,400,000
Intangible assets related to the marketed products                                         688,400,000 262,800,000 951,200,000          
Asset impairment charges 26,600,000 136,000,000 26,630,000 136,000,000 0                     26,600,000                        
Indefinite-lived intangible assets 266,200,000 29,530,000 266,200,000 29,530,000                                                
Percentage of shares acquired on outstanding shares of common stock                                   89.00%                    
Fair value of vested stock options                                   15,700,000                    
Business acquisition, equity interest issued or issuable, basis for determining value                                  

In accordance with the merger agreement, the number of Gilead stock options and restricted stock units into which assumed CV Therapeutics' stock options and restricted stock units were converted was determined based on an option conversion ratio. This conversion ratio was calculated by taking the per share acquisition price of $20.00 and dividing it by the average closing price of our common stock for the five consecutive trading days immediately preceding (but not including) the closing date of April 17, 2009, which was $46.24 per share. The fair value of stock options assumed was calculated using a Black-Scholes valuation model with the following assumptions: market price of $44.54 per share, which was the closing price of our common stock on the acquisition date; expected term ranging from 0.1 to 5.2 years; risk-free interest rate ranging from 0.1% to 1.7%; expected volatility ranging from 37.4% to 43.2%; and no dividend yield. The fair value of restricted stock units assumed was calculated using the acquisition-date closing price of $44.54 per share for our common stock.

                   
Completed IPR&D project                                     2,900,000                  
Estimated fair value of unvested stock options and restricted stock units assumed                                   11,200,000                    
Deferred tax assets resulting from the acquisition primarily related to federal and state net operating loss and tax credit carryforwards                                   413,816,000                    
Deferred tax liabilities resulting from the acquisition primarily related to the difference between the book basis and tax basis of the intangible assets                                   426,861,000                    
Deferred tax liability reduced as result of impairment charges                                       49,700,000                
Valuation allowance related to deferred tax assets 9,209,000 13,040,000 9,209,000 13,040,000                           15,100,000                    
Senior Notes, stated interest rate                                                 2.75% 3.25% 2.00%  
Senior subordinated convertible notes - maturity date                                                 Dec. 31, 2012 Dec. 31, 2013 Dec. 31, 2023  
Fair value of consideration transferred for business acquisition                 $ 225,000,000       $ 375,000,000   $ 102,100,000     $ 1,392,558,000