Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Jul. 28, 2018	Jul. 29, 2017
ASSETS
Allowance for doubtful accounts and returns	$ 285	$ 443
Sales-type and direct-financing leases	171	277
Inventory write-downs and capitalization	289	446
Investment provisions	54	171
IPR&D, goodwill, and purchased intangible assets	63	125
Deferred revenue	1,584	2,057
Credits and net operating loss carryforwards	1,087	976
Share-based compensation expense	190	273
Accrued compensation	370	504
Other	408	559
Gross deferred tax assets	4,501	5,831
Valuation allowance	(374)	(244)
Total deferred tax assets	4,127	5,587
LIABILITIES
Purchased intangible assets	(753)	(1,037)
Depreciation	(118)	(340)
Unrealized gains on investments	(33)	(203)
Other	(145)	(39)
Total deferred tax liabilities	(1,049)	(1,619)
Total net deferred tax assets	$ 3,078	$ 3,968