v2.4.0.8
Common Shares (Details) (USD $)
 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Common Shares      
Common shares, shares authorized 800,000,000 800,000,000  
Common shares, par value (in dollars per share) $ 0.001 $ 0.001  
Common shares, shares issued 323,710,583 318,813,500  
Preferred shares, shares issued 0    
Shares purchased 0 0 0
Issuance of common shares for stock options exercised, net of surrender of unexercised stock options (in shares) 5,383,000 (3,625,000) 11,605,000
Preferred shares, shares authorized 25,000,000    
Preferred shares, par value (in dollars per share) $ 0.001    
Proceeds from stock options exercised $ 5,400,000 $ 17,400,000 $ 11,600,000
Amount paid to repurchase surrendered unexercised vested options to satisfy exercise price and related tax withholding obligations   21,000,000  
Common stock dividend declared (in dollars per share) $ 0.04    
Cash dividends paid 47,168,000    
Officers and directors
      
Common Shares      
Restricted stock awarded to executive officers, key employees & directors 4,847,376 944,015 1,096,379
Restricted shares awarded, average market price (in dollars per share) $ 16.28 $ 20.69 $ 27.32
Employees
      
Common Shares      
Issuance of common shares for stock options exercised, net of surrender of unexercised stock options (in shares) 1,284 807,142 82,138
Value of surrendered unexercised vested stock options   $ 79,600,000 $ 7,600,000