Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 30, 2017	Jul. 31, 2016	Aug. 02, 2015
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan, Service Cost	$ 26	$ 26	$ 28
Defined Benefit Plan, Interest Cost	86	98	105
Expected return on plan assets	(144)	(147)	(173)
Amortization of Prior Service Cost (Credit)	0	0	(1)
Defined Benefit Plan, Actuarial Gain (Loss)	198	(302)	(136)
Defined Benefit Plan, Recognized Net Loss Due to Curtailments	0	0	1
Defined Benefit Plan, Net Periodic Benefit Cost	(230)	279	96
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan, Service Cost	1	1	2
Defined Benefit Plan, Interest Cost	10	15	15
Amortization of Prior Service Cost (Credit)	(25)	(1)	(1)
Defined Benefit Plan, Actuarial Gain (Loss)	14	(23)	(7)
Defined Benefit Plan, Recognized Net Loss Due to Curtailments	0	0	6
Defined Benefit Plan, Net Periodic Benefit Cost	$ (28)	$ 38	$ 29