v2.4.0.6
Stock-Based Compensation Plans (Details) (USD $)
 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Shares    
Exercised (in shares) (318,175)  
Granted (in shares) 113,804 144,827
Additional disclosures    
Share-based compensation expense $ 6,106,000 $ 5,575,000
Capitalized stock-based compensation cost 2,603,000 2,907,000
Stock Options
    
Additional disclosures    
Unrecognized compensation cost for unvested stock options 3,355,000  
Weighted average period for recognition of unrecognized compensation cost 2 years 1 month 20 days  
Restricted stock
    
Additional disclosures    
Outstanding unvested shares granted 208,436  
Shares vested 317,050  
Total fair value of shares vested 36,162,000 34,882,000
Weighted average period for recognition of unrecognized compensation cost 2 years 8 months 16 days  
Unrecognized compensation cost for unvested restricted stock $ 9,807,000  
Restricted stock | Minimum
    
Additional disclosures    
Grant date fair value per share (in dollars per share) $ 48.60  
Restricted stock | Maximum
    
Additional disclosures    
Grant date fair value per share (in dollars per share) $ 139.75  
2009 Plan | Stock Options
    
Shares    
Options outstanding at the beginning of the period (in shares) 247,403,000  
Exercised (in shares) (36,953,000)  
Granted (in shares) 113,804,000  
Forfeited (in shares) (2,396,000)  
Options outstanding at the end of the period (in shares) 321,858,000  
Options exercisable at the end of the period (in shares) 80,930,000  
Weighted average exercise price per share    
Options outstanding at the beginning of the period (in dollars per share) $ 98.42  
Exercised (in dollars per share) $ 84.74  
Granted (in dollars per share) 132.95  
Forfeited (in dollars per share) $ 99.69  
Options outstanding at the end of the period (in dollars per share) $ 112.19  
Options exercisable at the end of the period (in dollars per share) $ 96.66  
Additional disclosures    
Weighted average fair value per share (in dollars per share) $ 29.05  
Weighted average assumptions    
Dividend yield (as a percent) 3.50%  
Volatility (as a percent) 35.00%  
Risk-free interest rate (as a percent) 0.90%  
Expected life of option (in years) 5 years  
1994 Plan | Stock Options
    
Shares    
Options outstanding at the beginning of the period (in shares) 1,112,959,000  
Exercised (in shares) (281,222,000)  
Forfeited (in shares) (4,066,000)  
Options outstanding at the end of the period (in shares) 827,671,000  
Options exercisable at the end of the period (in shares) 827,671,000  
Weighted average exercise price per share    
Options outstanding at the beginning of the period (in dollars per share) $ 94.10  
Exercised (in dollars per share) $ 67.88  
Forfeited (in dollars per share) $ 116.89  
Options outstanding at the end of the period (in dollars per share) $ 102.90  
Options exercisable at the end of the period (in dollars per share) $ 102.90