Goodwill And Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 29, 2017	Oct. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 4	$ 5
Finite-Lived Intangible Assets, Amortization Expense, Current Year	16
Finite-Lived Intangible Assets, Amortization Expense, Year Two	16
Finite Lived Intangible Assets, Amortization Expense, Year Three	15
Finite Lived Intangible Assets, Amortization Expense, Year Four	15
Finite Lived Intangible Assets, Amortization Expense, Year Five	$ 15
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	20 years