Employee Stock Plans (Summary Of Significant Ranges Of Outstanding And Exercisable Stock Options) (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Oct. 26, 2013	Jul. 27, 2013	Jul. 28, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	249	276	520
Stock options outstanding, weighted-average remaining contractual life	2 years 4 months 2 days
Stock options outstanding, weighted-average exercise price per share	$ 24.62	$ 24.44	$ 22.68
Stock options outstanding, aggregate intrinsic value	$ 418
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	244	271
Stock options exercisable, weighted-average exercise price per share	$ 25.08	$ 24.84
Stock options exercisable, aggregate intrinsic value	316
$0.01 - 15.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	11
Stock options outstanding, weighted-average remaining contractual life	5 years 6 months 14 days
Stock options outstanding, weighted-average exercise price per share	$ 4.66
Stock options outstanding, aggregate intrinsic value	198
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	6
Stock options exercisable, weighted-average exercise price per share	$ 6.25
Stock options exercisable, aggregate intrinsic value	96
Range of exercise price of stock options outstanding and exercisable, minimum	$ 0.01
Range of exercise price of stock options outstanding and exercisable, maximum	$ 15.00
$15.01 - 18.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	35
Stock options outstanding, weighted-average remaining contractual life	11 months 16 days
Stock options outstanding, weighted-average exercise price per share	$ 17.79
Stock options outstanding, aggregate intrinsic value	165
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	35
Stock options exercisable, weighted-average exercise price per share	$ 17.79
Stock options exercisable, aggregate intrinsic value	165
Range of exercise price of stock options outstanding and exercisable, minimum	$ 15.01
Range of exercise price of stock options outstanding and exercisable, maximum	$ 18.00
$18.01 - 20.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	13
Stock options outstanding, weighted-average remaining contractual life	9 months 22 days
Stock options outstanding, weighted-average exercise price per share	$ 19.13
Stock options outstanding, aggregate intrinsic value	43
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	13
Stock options exercisable, weighted-average exercise price per share	$ 19.13
Stock options exercisable, aggregate intrinsic value	43
Range of exercise price of stock options outstanding and exercisable, minimum	$ 18.01
Range of exercise price of stock options outstanding and exercisable, maximum	$ 20.00
$20.01 - 25.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	79
Stock options outstanding, weighted-average remaining contractual life	1 year 11 months 26 days
Stock options outstanding, weighted-average exercise price per share	$ 22.83
Stock options outstanding, aggregate intrinsic value	12
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	79
Stock options exercisable, weighted-average exercise price per share	$ 22.83
Stock options exercisable, aggregate intrinsic value	12
Range of exercise price of stock options outstanding and exercisable, minimum	$ 20.01
Range of exercise price of stock options outstanding and exercisable, maximum	$ 25.00
$25.01 - 35.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	111
Stock options outstanding, weighted-average remaining contractual life	2 years 10 months 13 days
Stock options outstanding, weighted-average exercise price per share	$ 30.69
Stock options outstanding, aggregate intrinsic value	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	111
Stock options exercisable, weighted-average exercise price per share	$ 30.69
Stock options exercisable, aggregate intrinsic value	$ 0
Range of exercise price of stock options outstanding and exercisable, minimum	$ 25.01
Range of exercise price of stock options outstanding and exercisable, maximum	$ 35.00