Employee Benefit Plans (Summary Assumptions Related To And Valuation Of Employee Share-Based Awards (Time-Based Restricted Stock Units)) (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 26, 2013	Jan. 28, 2012	Jan. 26, 2013	Jan. 28, 2012
Time Based Restricted Stock Units R S U [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	3.10%	1.30%	3.00%	1.30%
Time Based Restricted Stock Units R S U [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	37	33	48	44
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	17.07	17.88	17.20	17.34