Goodwill and Purchased Intangible Assets (Schedule Of Amortization Of Purchased Intangible Assets) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 25, 2015	Apr. 26, 2014	Apr. 25, 2015	Apr. 26, 2014
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets	$ 70us-gaap_AmortizationOfIntangibleAssets	$ 71us-gaap_AmortizationOfIntangibleAssets	$ 213us-gaap_AmortizationOfIntangibleAssets	$ 207us-gaap_AmortizationOfIntangibleAssets
Cost of sales
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets	187	190	618	553
Operating expenses
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets		71		207
Total
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets	$ 257	$ 261	$ 831	$ 760