Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 27, 2019	Oct. 28, 2018
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	$ 5	$ 5
Defined Benefit Plan, Interest Cost	17	21
Expected return on plan assets	(34)	(36)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	(1)	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(13)	(10)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Service Cost	0	0
Defined Benefit Plan, Interest Cost	2	2
Expected return on plan assets	0	0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(7)	(7)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (5)	$ (5)