Income Taxes (Components Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions	Jul. 25, 2015	Jul. 26, 2014
Income Tax Disclosure [Abstract]
Allowance for doubtful accounts and returns	$ 417	$ 464
Sales-type and direct-financing leases	266	231
Inventory write-downs and capitalization	345	307
Investment provisions	112	212
IPR&D, goodwill, and purchased intangible assets	134	135
Deferred revenue	1,795	1,689
Credits and net operating loss carryforwards	746	796
Share-based compensation expense	520	661
Accrued compensation	467	496
Other	670	676
Gross deferred tax assets	5,472	5,667
Valuation allowance	(84)	(114)
Total deferred tax assets	5,388	5,553
Purchased intangible assets	(950)	(1,229)
Depreciation	(143)	(48)
Unrealized gains on investments	(175)	(245)
Other	(15)	(26)
Total deferred tax liabilities	(1,283)	(1,548)
Total net deferred tax assets	$ 4,105	$ 4,005