Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (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]
Service cost	$ 55	$ 58	$ 55
Interest cost	122	121	121
Expected return on plan assets	(178)	(178)	(170)
Amortization of Prior Service Cost (Credit)	0	1	1
Recognized net actuarial loss	74	70	49
Settlements (gains)/costs	0	(1)	12
Net periodic benefit expense	73	71	68
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	3	3
Interest cost	18	18	19
Amortization of Prior Service Cost (Credit)	(1)	(1)	1
Recognized net actuarial loss	9	7	1
Net periodic benefit expense	$ 29	$ 27	$ 24