Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 27, 2019	Jan. 28, 2018	Jan. 27, 2019	Jan. 28, 2018
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	$ 6	$ 6	$ 11	$ 12
Defined Benefit Plan, Interest Cost	20	18	41	37
Expected return on plan assets	(35)	(36)	(71)	(72)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0	0	0
Defined Benefit Plan, Cost of Providing Special and Contractual Termination Benefits	0	2	0	2
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(9)	(10)	(19)	(21)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	0	0	0	0
Defined Benefit Plan, Interest Cost	2	2	4	4
Expected return on plan assets	0	0	0	0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(7)	(6)	(14)	(13)
Defined Benefit Plan, Cost of Providing Special and Contractual Termination Benefits	0	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (5)	$ (4)	$ (10)	$ (9)