Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 29, 2018	Jul. 30, 2017	Jul. 31, 2016
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	$ 24	$ 26	$ 26
Defined Benefit Plan, Interest Cost	74	86	98
Expected return on plan assets	(144)	(144)	(147)
Defined Benefit Plan, Actuarial Gain (Loss)	(104)	(198)	302
Defined Benefit Plan, Cost of Providing Special and Contractual Termination Benefits	2	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	(2)	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(150)	(230)	279
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	1	1	1
Defined Benefit Plan, Interest Cost	7	10	15
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(27)	(25)	(1)
Defined Benefit Plan, Actuarial Gain (Loss)	(16)	(14)	23
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (35)	$ (28)	$ 38