Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Oct. 27, 2013	Oct. 28, 2012
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 11	$ 14
Interest cost	29	27
Expected return on plan assets	(45)	(44)
Recognized net actuarial loss	19	27
Net periodic benefit expense	14	24
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	4	4
Expected return on plan assets	0	0
Recognized net actuarial loss	3	3
Net periodic benefit expense	$ 8	$ 8