Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2016	Aug. 02, 2015	Aug. 03, 2014
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan, Service Cost	$ 26	$ 28	$ 42
Defined Benefit Plan, Interest Cost	98	105	115
Expected return on plan assets	(147)	(173)	(169)
Amortization of Prior Service Cost (Credit)	0	(1)	(1)
Defined Benefit Plan, Actuarial Gain (Loss)	(302)	(136)	(48)
Defined Benefit Plan, Recognized Net Loss Due to Curtailments	0	1	0
Defined Benefit Plan, Net Periodic Benefit Cost	279	96	35
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan, Service Cost	1	2	2
Defined Benefit Plan, Interest Cost	15	15	17
Amortization of Prior Service Cost (Credit)	(1)	(1)	(1)
Defined Benefit Plan, Actuarial Gain (Loss)	(23)	(7)	(5)
Defined Benefit Plan, Recognized Net Loss Due to Curtailments	0	6	0
Defined Benefit Plan, Net Periodic Benefit Cost	$ 38	$ 29	$ 23