Pension And Postretirement Benefits Pension And Postretirement Benefits (Schedule Of Change In Benefit Obligation) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 29, 2012	Jul. 31, 2011	Aug. 01, 2010
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	$ 2,388	$ 2,275
Service cost	55	58	55
Interest cost	122	121	121
Actuarial loss	361	61
Participant contributions	0	0
Benefits paid	(157)	(146)
Medicare subsidies	0	0
Other	(5)	(4)
Plan amendments	0	(1)
Settlements	0	(8)
Foreign currency adjustment	(16)	32
Benefit obligation at end of year	2,748	2,388	2,275
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	374	362
Service cost	3	3	3
Interest cost	18	18	19
Actuarial loss	47	15
Participant contributions	6	5
Benefits paid	(38)	(34)
Medicare subsidies	3	5
Other	0	0
Plan amendments	0	0
Settlements	0	0
Foreign currency adjustment	0	0
Benefit obligation at end of year	$ 413	$ 374	$ 362