Goodwill And Intangible Assets (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Oct. 28, 2012	Oct. 30, 2011
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 3	$ 1
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	15
Finite-Lived Intangible Assets, Amortization Expense, Year Two	15
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]
Asset useful lives minimum range, years	5 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Asset useful lives minimum range, years	20 years