Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 27, 2014	Apr. 28, 2013	Apr. 27, 2014	Apr. 28, 2013
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 11	$ 15	$ 32	$ 43
Interest cost	29	27	87	81
Expected return on plan assets	(44)	(44)	(133)	(133)
Amortization of Prior Service Cost (Credit)	(1)	0	(1)	(1)
Recognized net actuarial loss	20	27	58	81
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	0	0	(3)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	18	0	18	0
Net periodic benefit expense	33	25	61	74
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	3
Interest cost	4	3	13	11
Expected return on plan assets	0	0	0	0
Amortization of Prior Service Cost (Credit)	0	0	(1)	(1)
Recognized net actuarial loss	2	4	9	11
Net periodic benefit expense	$ 7	$ 8	$ 23	$ 24