Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 26, 2020	Jan. 27, 2019	Jan. 26, 2020	Jan. 27, 2019
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 5	$ 6	$ 10	$ 11
Defined Benefit Plan, Interest Cost	17	20	34	41
Expected return on plan assets	(34)	(35)	(69)	(71)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	(11)	0	(11)	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(23)	(9)	(36)	(19)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	0	0	0	0
Defined Benefit Plan, Interest Cost	1	2	3	4
Expected return on plan assets	0	0	0	0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(7)	(7)	(14)	(14)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	0	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (6)	$ (5)	$ (11)	$ (10)