Employee Benefit Plans (Summary Of Significant Ranges Of Outstanding And Exercisable Stock Options) (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Jul. 27, 2013	Jul. 28, 2012	Jul. 30, 2011	Jul. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	276	520	621	732
Stock Options Outstanding, Weighted-Average Remaining Contractual Life (in Years)	2 years 5 months 12 days
Stock Options Outstanding, Weighted- Average Exercise Price per Share, dollars per share	$ 24.44	$ 22.68	$ 21.79	$ 21.39
Stock Options Outstanding, Aggregate Intrinsic Value	$ 892
Stock Options Exercisable, shares	271	512
Stock Options Exercisable, Weighted-Average Exercise Price per Share, dollars per share	$ 24.84	$ 22.65
Stock Options Exercisible, Aggregate Intrinsic Value	777
$ 0.01 – 15.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	9
Stock Options Outstanding, Weighted-Average Remaining Contractual Life (in Years)	6 years 2 months 5 days
Stock Options Outstanding, Weighted- Average Exercise Price per Share, dollars per share	$ 3.99
Stock Options Outstanding, Aggregate Intrinsic Value	198
Stock Options Exercisable, shares	5
Stock Options Exercisable, Weighted-Average Exercise Price per Share, dollars per share	$ 7.00
Stock Options Exercisible, Aggregate Intrinsic Value	84
15.01 – 18.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	40
Stock Options Outstanding, Weighted-Average Remaining Contractual Life (in Years)	1 year 2 months 12 days
Stock Options Outstanding, Weighted- Average Exercise Price per Share, dollars per share	$ 17.79
Stock Options Outstanding, Aggregate Intrinsic Value	308
Stock Options Exercisable, shares	40
Stock Options Exercisable, Weighted-Average Exercise Price per Share, dollars per share	$ 17.79
Stock Options Exercisible, Aggregate Intrinsic Value	307
18.01 – 20.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	25
Stock Options Outstanding, Weighted-Average Remaining Contractual Life (in Years)	8 months 5 days
Stock Options Outstanding, Weighted- Average Exercise Price per Share, dollars per share	$ 19.15
Stock Options Outstanding, Aggregate Intrinsic Value	155
Stock Options Exercisable, shares	24
Stock Options Exercisable, Weighted-Average Exercise Price per Share, dollars per share	$ 19.15
Stock Options Exercisible, Aggregate Intrinsic Value	155
20.01 – 25.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	86
Stock Options Outstanding, Weighted-Average Remaining Contractual Life (in Years)	2 years 2 months 19 days
Stock Options Outstanding, Weighted- Average Exercise Price per Share, dollars per share	$ 22.82
Stock Options Outstanding, Aggregate Intrinsic Value	231
Stock Options Exercisable, shares	86
Stock Options Exercisable, Weighted-Average Exercise Price per Share, dollars per share	$ 22.82
Stock Options Exercisible, Aggregate Intrinsic Value	231
25.01 – 35.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	116
Stock Options Outstanding, Weighted-Average Remaining Contractual Life (in Years)	3 years 1 month 13 days
Stock Options Outstanding, Weighted- Average Exercise Price per Share, dollars per share	$ 30.69
Stock Options Outstanding, Aggregate Intrinsic Value	0
Stock Options Exercisable, shares	116
Stock Options Exercisable, Weighted-Average Exercise Price per Share, dollars per share	$ 30.69
Stock Options Exercisible, Aggregate Intrinsic Value	$ 0