Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 26, 2014	Jan. 27, 2013	Jan. 26, 2014	Jan. 27, 2013
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 10	$ 14	$ 21	$ 28
Interest cost	29	27	58	54
Expected return on plan assets	(44)	(45)	(89)	(89)
Amortization of Prior Service Cost (Credit)	0	(1)	0	(1)
Recognized net actuarial loss	19	27	38	54
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	(3)	0	(3)
Net periodic benefit expense	14	25	28	49
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	1	1	2
Interest cost	5	4	9	8
Expected return on plan assets	0	0	0	0
Amortization of Prior Service Cost (Credit)	(1)	(1)	(1)	(1)
Recognized net actuarial loss	4	4	7	7
Net periodic benefit expense	$ 8	$ 8	$ 16	$ 16