Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Jul. 29, 2017	Jul. 30, 2016
ASSETS
Allowance for doubtful accounts and returns	$ 443	$ 524
Sales-type and direct-financing leases	277	289
Inventory write-downs and capitalization	446	417
Investment provisions	171	126
IPR&D, goodwill, and purchased intangible assets	125	139
Deferred revenue	2,057	1,858
Credits and net operating loss carryforwards	976	863
Share-based compensation expense	273	438
Accrued compensation	504	572
Other	559	516
Gross deferred tax assets	5,831	5,742
Valuation allowance	(244)	(134)
Total deferred tax assets	5,587	5,608
LIABILITIES
Purchased intangible assets	(1,037)	(995)
Depreciation	(340)	(289)
Unrealized gains on investments	(203)	(225)
Other	(39)	(78)
Total deferred tax liabilities	(1,619)	(1,587)
Total net deferred tax assets	$ 3,968	$ 4,021