Employee Benefit Plans (Summary Of Significant Ranges Of Outstanding And Exercisable Stock Options) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Oct. 25, 2014	Jul. 26, 2014	Jul. 27, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (in shares)	163	187	276
Weighted- Average Remaining Contractual Life (in Years)	1 year 7 months 6 days
Weighted- Average Exercise Price per Share	$ 26.63	$ 26.03	$ 24.44
Aggregate Intrinsic Value	$ 212
Number Exercisable, shares	159	183
Weighted- Average Exercise Price per Share	$ 27.13	$ 26.50
Aggregate Intrinsic Value	141
$ 0.01 – 15.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (in shares)	7
Weighted- Average Remaining Contractual Life (in Years)	5 years 3 months 18 days
Weighted- Average Exercise Price per Share	$ 4.07
Aggregate Intrinsic Value	145
Number Exercisable, shares	4
Weighted- Average Exercise Price per Share	$ 5.41
Aggregate Intrinsic Value	74
15.01 – 18.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (in shares)	1
Weighted- Average Remaining Contractual Life (in Years)	1 year
Weighted- Average Exercise Price per Share	$ 17.32
Aggregate Intrinsic Value	7
Number Exercisable, shares	1
Weighted- Average Exercise Price per Share	$ 17.32
Aggregate Intrinsic Value	7
18.01 – 20.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (in shares)	2
Weighted- Average Remaining Contractual Life (in Years)	0 years 6 months
Weighted- Average Exercise Price per Share	$ 19.60
Aggregate Intrinsic Value	9
Number Exercisable, shares	2
Weighted- Average Exercise Price per Share	$ 19.60
Aggregate Intrinsic Value	9
20.01 – 25.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (in shares)	55
Weighted- Average Remaining Contractual Life (in Years)	1 year
Weighted- Average Exercise Price per Share	$ 22.87
Aggregate Intrinsic Value	51
Number Exercisable, shares	54
Weighted- Average Exercise Price per Share	$ 22.87
Aggregate Intrinsic Value	51
25.01 – 30.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (in shares)	26
Weighted- Average Remaining Contractual Life (in Years)	1 year 8 months 12 days
Weighted- Average Exercise Price per Share	$ 26.59
Aggregate Intrinsic Value	0
Number Exercisable, shares	26
Weighted- Average Exercise Price per Share	$ 26.59
Aggregate Intrinsic Value	0
30.01 – 35.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding (in shares)	72
Weighted- Average Remaining Contractual Life (in Years)	1 year 9 months 18 days
Weighted- Average Exercise Price per Share	$ 32.16
Aggregate Intrinsic Value	0
Number Exercisable, shares	72
Weighted- Average Exercise Price per Share	$ 32.16
Aggregate Intrinsic Value	$ 0