Pension And Postretirement Benefits Pension And Postretirement Benefits (Schedule Of Changes In Fair Value Of Level 3 Investments) (Details) - Pension Plan, Defined Benefit [Member] - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2016	Aug. 02, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 2,316	$ 2,364
Defined Benefit Plan, Actual Return on Plan Assets	54	143
Defined Benefit Plan, Fair Value of Plan Assets	2,111	2,316
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	45	33
Defined Benefit Plan, Actual Return on Plan Assets	2	3
Defined Benefit Plan, Purchase of Plan Assets	5	9
Defined Benefit Plan, Sale of Plan Assets	(1)	0
Defined Benefit Plan, Settlements	0	0
Defined Benefit Plan, Transfers Between Measurement Levels	0	0
Defined Benefit Plan, Fair Value of Plan Assets	51	45
Fair Value, Inputs, Level 3 [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	6	3
Defined Benefit Plan, Actual Return on Plan Assets	1	1
Defined Benefit Plan, Purchase of Plan Assets	0	2
Defined Benefit Plan, Sale of Plan Assets	(1)	0
Defined Benefit Plan, Settlements	0	0
Defined Benefit Plan, Transfers Between Measurement Levels	0	0
Defined Benefit Plan, Fair Value of Plan Assets	6	6
Fair Value, Inputs, Level 3 [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	39	30
Defined Benefit Plan, Actual Return on Plan Assets	1	2
Defined Benefit Plan, Purchase of Plan Assets	5	7
Defined Benefit Plan, Sale of Plan Assets	0	0
Defined Benefit Plan, Settlements	0	0
Defined Benefit Plan, Transfers Between Measurement Levels	0	0
Defined Benefit Plan, Fair Value of Plan Assets	$ 45	$ 39