Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	May. 01, 2016	May. 03, 2015	May. 01, 2016	May. 03, 2015
Defined Benefit Plan Disclosure [Line Items]
Recognized net actuarial loss	$ 54	$ 26	$ 175	$ 26
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	6	8	20	22
Defined Benefit Plan, Interest Cost	24	26	74	79
Expected return on plan assets	(36)	(43)	(111)	(130)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(1)	(1)	(1)	(1)
Recognized net actuarial loss	61	5	173	5
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	1	0	1
Defined Benefit Plan, Net Periodic Benefit Cost	54	(4)	155	(24)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	0	1	1	2
Defined Benefit Plan, Interest Cost	4	3	12	11
Expected return on plan assets	0	0	0	0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0	(1)	(1)
Recognized net actuarial loss	0	22	0	22
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	6	0	6
Defined Benefit Plan, Net Periodic Benefit Cost	$ 4	$ 32	$ 12	$ 40