Subsequent Events (Details Textual) (USD $) In Millions, except Per Share data, unless otherwise specified	Oct. 25, 2011	Oct. 13, 2011	Oct. 01, 2011
Subsequent Events [Abstract]
Percentage of the convertible notes tendered by holders.		37.50%
Number of common shares covered under the call options	28.6		45.7
Number of shares covered under the warrants	28.0
Principal amount of Convertible Notes tendered by holders		$ 225
Proceeds from call option transaction	135
Payment for warrant transaction	133
Cost for capped call transactions	$ 32
Number of shares covered under capped call transactions	17.1
Strike price of capped call transactions	$ 13.125
Cap price of of capped call transactions	$ 15.75
Expiration date of capped call transactions	May 2013