Goodwill and Purchased Intangible Assets (Schedule Of Amortization Of Purchased Intangible Assets) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 23, 2016	Jan. 24, 2015	Jan. 23, 2016	Jan. 24, 2015
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets	$ 71	$ 72	$ 140	$ 143
Cost of sales
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets	139	242	285	431
Operating expenses
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets	71	72	140	143
Total
Acquired Intangible Asset Amortization by Statement of Operations Class [Line Items]
Amortization of purchased intangible assets	$ 210	$ 314	$ 425	$ 574