XML 51 R30.htm IDEA: XBRL DOCUMENT v2.3.0.15
Share-Based Compensation (Tables)
9 Months Ended
Sep. 30, 2011
Share-Based Compensation [Abstract] 
Schedule Of Weighted Averages Of The Assumptions Used In Estimating The Fair Value Of Stock Option Awards
   
For the Nine Months Ended
September 30,
 
   
2011
   
2010
 
             
Expected stock price volatility
    33 %     31 %
Expected term, in years
    4.8       4.9  
Risk-free interest rate
    2.3 %     2.3 %
                 
Weighted average fair value of options granted
  $ 24.87     $ 16.56