v2.3.0.11
Stock-Based Compensation (Details 2) (USD $)
6 Months Ended 3 Months Ended
Jun. 30, 2011
Stock Option [Member]
Jun. 30, 2010
Stock Option [Member]
Jun. 30, 2011
Performance Retention Awards [Member]
Feb. 03, 2011
Performance Retention Awards [Member]
Assumptions For Stock Awards [Abstract]        
Risk-free interest rate 2.30% 2.40%    
Dividend yield 1.60% 1.80%    
Expected life (years) 5.30 5.40    
Volatility 35.90% 35.20%    
Weighted-average grant-date fair value of options granted $ 28.45 $ 18.26    
Risk-free interest rate at date of grant     1.20%  
Continued employment requirement       Stock units awarded to selected employees under these grants are subject to continued employment for 37 months and the attainment of certain levels of ROIC.
Dividend per share for the quarter     $ 0.38