Goodwill And Purchased Intangible Assets (Schedule Of Amortization Of Purchased Intangible Assets) (Details) (USD $) In Millions	3 Months Ended
	Oct. 29, 2011	Oct. 30, 2010
Acquired Finite-Lived Intangible Assets [Line Items]
Total	$ 195	$ 219
Cost Of Sales [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	96	106
Operating Expenses [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 99	$ 113