Goodwill And Purchased Intangible Assets (Schedule Of Amortization Of Purchased Intangible Assets) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Oct. 26, 2013	Oct. 27, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of Purchased Intangible Assets	$ 65	$ 122
Cost of Sales [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of Purchased Intangible Assets	174	143
Operating Expenses [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of Purchased Intangible Assets	65	122
Cost of Sales and Operating Expenses [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of Purchased Intangible Assets	$ 239	$ 265