v2.4.0.6
Employee Benefit Plans (Summary Assumptions Related To And Valuation Of Employee Share-Based Awards (Employee Stock Purchase Rights)) (Detail) (USD $)
0 Months Ended 12 Months Ended
Mar. 17, 2011
Jul. 28, 2012
Employee Stock Purchase Rights
Year
Jul. 30, 2011
Employee Stock Purchase Rights
Year
Jul. 31, 2010
Employee Stock Purchase Rights
Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Expected volatility   27.20% 35.10% 34.80%
Risk-free interest rate   0.20% 0.90% 0.40%
Expected dividend 0.00% 1.50% 0.00% 0.00%
Expected life (in years)   0.8 1.8 0.8
Weighted-average estimated grant date fair value per share   $ 3.81 $ 6.31 $ 5.03