Pension And Postretirement Benefits (Schedule of Change in Benefit Obligation) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2016	Aug. 02, 2015	Aug. 03, 2014
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	$ 2,569	$ 2,539
Defined Benefit Plan, Service Cost	26	28	$ 42
Defined Benefit Plan, Interest Cost	98	105	115
Defined Benefit Plan, Actuarial Gain (Loss)	210	106
Defined Benefit Plan, Contributions by Plan Participants	0	0
Defined Benefit Plan, Plan Amendments	0	0
Defined Benefit Plan, Benefits Paid	(116)	(151)
Defined Benefit Plan, Settlements, Benefit Obligation	(160)	0
Defined Benefit Plan, Gross Prescription Drug Subsidy Receipts Received	0	0
Defined Benefit Plan, Other Changes	(6)	(1)
Defined Benefit Plan, Curtailments	0	1
Defined Benefit Plan, Foreign Currency Exchange Rate Gain (Loss)	5	(58)
Defined Benefit Plan, Benefit Obligation	2,626	2,569	2,539
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	392	388
Defined Benefit Plan, Service Cost	1	2	2
Defined Benefit Plan, Interest Cost	15	15	17
Defined Benefit Plan, Actuarial Gain (Loss)	23	7
Defined Benefit Plan, Contributions by Plan Participants	1	3
Defined Benefit Plan, Plan Amendments	(93)	0
Defined Benefit Plan, Benefits Paid	(30)	(33)
Defined Benefit Plan, Settlements, Benefit Obligation	0	0
Defined Benefit Plan, Gross Prescription Drug Subsidy Receipts Received	4	4
Defined Benefit Plan, Other Changes	0	0
Defined Benefit Plan, Curtailments	0	6
Defined Benefit Plan, Foreign Currency Exchange Rate Gain (Loss)	0	0
Defined Benefit Plan, Benefit Obligation	$ 313	$ 392	$ 388