Income Taxes (Components Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions	Jul. 30, 2016	Jul. 25, 2015
Income Tax Disclosure [Abstract]
Allowance for doubtful accounts and returns	$ 524	$ 417
Sales-type and direct-financing leases	289	266
Inventory write-downs and capitalization	417	345
Investment provisions	126	112
IPR&D, goodwill, and purchased intangible assets	139	134
Deferred revenue	1,858	1,795
Credits and net operating loss carryforwards	863	746
Share-based compensation expense	438	520
Accrued compensation	572	467
Other	516	670
Gross deferred tax assets	5,742	5,472
Valuation allowance	(134)	(84)
Total deferred tax assets	5,608	5,388
Purchased intangible assets	(995)	(950)
Depreciation	(289)	(143)
Unrealized gains on investments	(225)	(175)
Other	(78)	(15)
Total deferred tax liabilities	(1,587)	(1,283)
Total net deferred tax assets	$ 4,021	$ 4,105