Pension And Postretirement Benefits (Schedule Of Components of Benefit Expense) (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 29, 2017	Oct. 30, 2016
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 6	$ 6
Defined Benefit Plan, Interest Cost	19	22
Expected return on plan assets	(36)	(36)
Amortization of Prior Service Cost (Credit)	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(11)	(8)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	0	0
Defined Benefit Plan, Interest Cost	2	3
Expected return on plan assets	0	0
Amortization of Prior Service Cost (Credit)	(7)	(6)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (5)	$ (3)