Goodwill and Purchased Intangible Assets (Schedule Of Amortization Of Purchased Intangible Assets) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 28, 2017	Jan. 23, 2016	Jan. 28, 2017	Jan. 23, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 64	$ 71	$ 142	$ 140
Cost of sales
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	124	139	253	285
Amortization of purchased intangible assets
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	64	71	142	140
Restructuring and other charges
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	0	0	38	0
Total
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 188	$ 210	$ 433	$ 425