Supplementary Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Jul. 28, 2018	Apr. 28, 2018	Jan. 27, 2018	Oct. 28, 2017	Jul. 29, 2017	Apr. 29, 2017	Jan. 28, 2017	Oct. 29, 2016	Jul. 28, 2018	Jul. 29, 2017	Jul. 30, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 12,844	$ 12,463	$ 11,887	$ 12,136	$ 12,133	$ 11,940	$ 11,580	$ 12,352	$ 49,330	$ 48,005	$ 49,247
Gross margin	7,922	7,759	7,498	7,427	7,546	7,518	7,276	7,884	30,606	30,224	30,960
Operating income	3,346	3,134	3,073	2,756	3,034	3,169	2,893	2,877	12,309	11,973	12,660
Net income (loss)	$ 3,803	$ 2,691	$ (8,778)	$ 2,394	$ 2,424	$ 2,515	$ 2,348	$ 2,322	$ 110	$ 9,609	$ 10,739
Net income per share—basic (in dollars per share)	$ 0.81	$ 0.56	$ (1.78)	$ 0.48	$ 0.49	$ 0.50	$ 0.47	$ 0.46	$ 0.02	$ 1.92	$ 2.13
Net income per share—diluted (in dollars per share)	0.81	0.56	(1.78)	0.48	0.48	0.50	0.47	0.46	0.02	1.90	2.11
Cash dividends declared per common share (in dollars per share)	$ 0.33	$ 0.33	$ 0.29	$ 0.29	$ 0.29	$ 0.29	$ 0.26	$ 0.26	$ 1.24	$ 1.1	$ 0.94
Cash and cash equivalents and investments	$ 46,548	$ 54,431	$ 73,683	$ 71,588	$ 70,492	$ 67,974	$ 71,845	$ 70,968	$ 46,548	$ 70,492
Tax Cuts and Jobs Act of 2017, transition tax expense	$ (863)		9,000						8,100
Tax Cuts and Jobs Act of 2017, provisional tax expense			11,100						10,400
Tax Cuts and Jobs Act of 2017, tax expense for foreign withholding tax			1,200						1,200
Tax Cuts and Jobs Act of 2017, re-measurement of net deferred tax assets			$ 900						$ 1,100