Restructuring Charges and Cost Savings Initiatives (Schedule Of Pre-Tax Charges) (Details) - USD ($) $ in Millions		12 Months Ended
		Jul. 31, 2016	Aug. 02, 2015		Aug. 03, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		$ 31	$ 102		$ 55
2015 Initiatives [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		206
Restructuring Charges		35	102
2015 Initiatives [Member] | Severance Pay And Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		128
2015 Initiatives [Member] | Implementation and Other Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		78
2014 Initiatives [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		50	54	[1]
Restructuring Charges		(4)			54
2014 Initiatives [Member] | Severance Pay And Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		37	41	[1]
Restructuring Charges		(4)			41
2014 Initiatives [Member] | Asset Impairment Accelerated Depreciation [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		12	12	[1]
Restructuring Charges		0			12
2014 Initiatives [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		1	$ 1	[1]
Restructuring Charges	[2]	0			1
2013 Initiatives [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		142
Restructuring Charges					$ 1
2013 Initiatives [Member] | Severance Pay And Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		31
2013 Initiatives [Member] | Asset Impairment Accelerated Depreciation [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		99
2013 Initiatives [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Cost Incurred to Date		$ 12

[1] Recognized as of August 2, 2015.

[2] Includes non-cash costs that are not reflected in the restructuring reserve in the Consolidated Balance Sheet.