Goodwill and Purchased Intangible Assets (Schedule Of Amortization Of Purchased Intangible Assets) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2016	Apr. 25, 2015	Apr. 30, 2016	Apr. 25, 2015
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets	$ 81	$ 70	$ 221	$ 213
Cost of sales
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets	134	187	419	618
Operating expenses
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets	81	70	221	213
Total
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets	$ 215	$ 257	$ 640	$ 831