Pension And Postretirement Benefits (Schedule Of Change In Benefit Obligation) (Details) (USD $) In Millions	12 Months Ended
	Jul. 31, 2011	Aug. 01, 2010	Aug. 02, 2009
Benefits paid	$ (139)	$ (142)
Settlement	(6)	(21)
Pension [Member]
Obligation at beginning of year	2,275	2,077
Service cost	58	55	46
Interest cost	121	121	122
Actuarial loss	61	181
Participant contributions
Benefits paid	(146)	(148)
Medicare subsidies
Other	(4)	(2)
Plan amendments	(1)
Settlement	(8)	(21)
Foreign currency adjustment	32	12
Benefit obligation at end of year	2,388	2,275	2,077
Postretirement [Member]
Obligation at beginning of year	362	340
Service cost	3	3	3
Interest cost	18	19	22
Actuarial loss	15	50
Participant contributions	5	4
Benefits paid	(34)	(39)
Medicare subsidies	5	3
Other
Plan amendments		(18)
Settlement
Foreign currency adjustment
Benefit obligation at end of year	$ 374	$ 362	$ 340