Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 26, 2020	Apr. 28, 2019	Apr. 26, 2020	Apr. 28, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), (Gain) Loss Due to Settlement	$ 54	$ 28	$ 43	$ 28
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	4	5	14	16
Defined Benefit Plan, Interest Cost	14	21	48	62
Expected return on plan assets	(31)	(36)	(100)	(107)
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	54	28	43	28
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	41	18	5	(1)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	0	1	0	1
Defined Benefit Plan, Interest Cost	2	2	5	6
Expected return on plan assets	0	0	0	0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(7)	(8)	(21)	(22)
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)	$ (5)	$ (5)	$ (16)	$ (15)