Stock-Based Compensation (Stock Options) (Details) (USD $)
In Millions, except Share data in Thousands, unless otherwise specified
0 Months Ended 3 Months Ended
Mar. 15, 2011
Apr. 30, 2011
Jan. 29, 2011
Grants of stock options - fair value per option $ 11.40    
Granted, shares   2,392  
Granted, weighted-average exercise price per share $ 36.58 $ 37  
Exercised, shares   (425)  
Exercised, weighted-average exercise price per share   $ 20  
Forfeited or expired, shares   (253)  
Forfeited or expired, weighted-average exercise price per share   $ 37  
Outstanding, shares   16,727 15,013
Outstanding, weighted-average exercise price per share   $ 36 $ 36
Exercisable, shares   10,636  
Exercisable, weighted-average exercise price per share   $ 41  
Employee Stock Option [Member]
     
Unrecognized compensation expense   $ 48  
Weighted average period over which unrecognized compensation is expected to be recognized (years)   1 Â