Goodwill and Purchased Intangible Assets (Schedule Of Amortization Of Purchased Intangible Assets) (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 28, 2017	Oct. 29, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 61	$ 78
Cost of sales
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	154	129
Amortization of purchased intangible assets
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	61	78
Restructuring and other charges
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	0	38
Total
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of purchased intangible assets	$ 215	$ 245