Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 28, 2013	Apr. 29, 2012	Apr. 28, 2013	Apr. 29, 2012
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 15	$ 14	$ 43	$ 41
Interest cost	27	31	81	92
Expected return on plan assets	(44)	(44)	(133)	(133)
Amortization of Prior Service Cost (Credit)	0	0	(1)	0
Recognized net actuarial loss	27	18	81	55
Curtailment loss			3
Net periodic benefit expense	25	19	74	55
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	0	3	2
Interest cost	3	4	11	13
Expected return on plan assets	0	0	0	0
Amortization of Prior Service Cost (Credit)	0	0	(1)	(1)
Recognized net actuarial loss	4	3	11	7
Net periodic benefit expense	$ 8	$ 7	$ 24	$ 21