Employee Stock Plans (Summary Of Significant Ranges Of Outstanding And Exercisable Stock Options) (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended
	Apr. 26, 2014	Jul. 27, 2013	Jul. 28, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	223	276	520
Stock options outstanding, weighted-average remaining contractual life	1 year 9 months 29 days
Stock options outstanding, weighted-average exercise price per share	$ 25.09	$ 24.44	$ 22.68
Stock options outstanding, aggregate intrinsic value	$ 348
Stock options exercisable (in shares)	218	271
Stock options exercisable, weighted-average exercise price per share	$ 25.57	$ 24.84
Stock options exercisable, aggregate intrinsic value	253
$0.01 - 15.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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
Stock options outstanding (in shares)	9
Stock options outstanding, weighted-average remaining contractual life	5 years 2 months 12 days
Stock options outstanding, weighted-average exercise price per share	$ 4.29
Stock options outstanding, aggregate intrinsic value	180
Stock options exercisable (in shares)	4
Stock options exercisable, weighted-average exercise price per share	$ 6.11
Stock options exercisable, aggregate intrinsic value	85
$15.01 - 18.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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
Stock options outstanding (in shares)	25
Stock options outstanding, weighted-average remaining contractual life	6 months
Stock options outstanding, weighted-average exercise price per share	$ 17.81
Stock options outstanding, aggregate intrinsic value	128
Stock options exercisable (in shares)	25
Stock options exercisable, weighted-average exercise price per share	$ 17.81
Stock options exercisable, aggregate intrinsic value	128
$18.01 - 20.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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
Stock options outstanding (in shares)	7
Stock options outstanding, weighted-average remaining contractual life	7 months 10 days
Stock options outstanding, weighted-average exercise price per share	$ 19.22
Stock options outstanding, aggregate intrinsic value	25
Stock options exercisable (in shares)	7
Stock options exercisable, weighted-average exercise price per share	$ 19.22
Stock options exercisable, aggregate intrinsic value	25
$20.01 - 25.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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
Stock options outstanding (in shares)	76
Stock options outstanding, weighted-average remaining contractual life	1 year 4 months 24 days
Stock options outstanding, weighted-average exercise price per share	$ 22.85
Stock options outstanding, aggregate intrinsic value	15
Stock options exercisable (in shares)	76
Stock options exercisable, weighted-average exercise price per share	$ 22.85
Stock options exercisable, aggregate intrinsic value	15
25.01 - 30.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of exercise price of stock options outstanding and exercisable, minimum	$ 25.01
Range of exercise price of stock options outstanding and exercisable, maximum	$ 30.00
Stock options outstanding (in shares)	28
Stock options outstanding, weighted-average remaining contractual life	2 years 1 month 17 days
Stock options outstanding, weighted-average exercise price per share	$ 26.59
Stock options outstanding, aggregate intrinsic value	0
Stock options exercisable (in shares)	28
Stock options exercisable, weighted-average exercise price per share	$ 26.59
Stock options exercisable, aggregate intrinsic value	0
30.01 - 35.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of exercise price of stock options outstanding and exercisable, minimum	$ 30.01
Range of exercise price of stock options outstanding and exercisable, maximum	$ 35.00
Stock options outstanding (in shares)	78
Stock options outstanding, weighted-average remaining contractual life	2 years 2 months 19 days
Stock options outstanding, weighted-average exercise price per share	$ 32.16
Stock options outstanding, aggregate intrinsic value	0
Stock options exercisable (in shares)	78
Stock options exercisable, weighted-average exercise price per share	$ 32.16
Stock options exercisable, aggregate intrinsic value	$ 0