Employee Benefit Plans (Summary Of Significant Ranges Of Outstanding And Exercisable Stock Options) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Jul. 26, 2014	Jul. 27, 2013	Jul. 28, 2012	Jul. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	187	276	520	621
Weighted- Average Remaining Contractual Life (in Years)	1 year 8 months 12 days
Weighted- Average Exercise Price per Share	$ 26.03	$ 24.44	$ 22.68	$ 21.79
Aggregate Intrinsic Value	$ 481
Number Exercisable	183	271
Weighted- Average Exercise Price per Share	$ 26.50	$ 24.84
Aggregate Intrinsic Value	394
$ 0.01 – 15.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	8
Weighted- Average Remaining Contractual Life (in Years)	5 years 2 months 12 days
Weighted- Average Exercise Price per Share	$ 4.00
Aggregate Intrinsic Value	172
Number Exercisable	4
Weighted- Average Exercise Price per Share	$ 5.54
Aggregate Intrinsic Value	85
15.01 – 18.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	11
Weighted- Average Remaining Contractual Life (in Years)	3 months 18 days
Weighted- Average Exercise Price per Share	$ 17.79
Aggregate Intrinsic Value	93
Number Exercisable	11
Weighted- Average Exercise Price per Share	$ 17.79
Aggregate Intrinsic Value	93
18.01 – 20.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	3
Weighted- Average Remaining Contractual Life (in Years)	8 months 12 days
Weighted- Average Exercise Price per Share	$ 19.38
Aggregate Intrinsic Value	20
Number Exercisable	3
Weighted- Average Exercise Price per Share	$ 19.38
Aggregate Intrinsic Value	20
20.01 – 25.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	62
Weighted- Average Remaining Contractual Life (in Years)	1 year 2 months 12 days
Weighted- Average Exercise Price per Share	$ 22.86
Aggregate Intrinsic Value	192
Number Exercisable	62
Weighted- Average Exercise Price per Share	$ 22.86
Aggregate Intrinsic Value	192
25.01 – 30.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	27
Weighted- Average Remaining Contractual Life (in Years)	1 year 10 months 24 days
Weighted- Average Exercise Price per Share	$ 26.59
Aggregate Intrinsic Value	4
Number Exercisable	27
Weighted- Average Exercise Price per Share	$ 26.59
Aggregate Intrinsic Value	4
30.01 – 35.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	76
Weighted- Average Remaining Contractual Life (in Years)	2 years
Weighted- Average Exercise Price per Share	$ 32.16
Aggregate Intrinsic Value	0
Number Exercisable	76
Weighted- Average Exercise Price per Share	$ 32.16
Aggregate Intrinsic Value	$ 0