Pension And Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 28, 2018	Jan. 29, 2017	Jan. 28, 2018	Jan. 29, 2017
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Cost of Providing Special and Contractual Termination Benefits	$ 2	$ 0	$ 2	$ 0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(10)	$ (8)	(21)	$ (16)
Change in Accounting Method [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (4)		$ (8)