Supplementary Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Jul. 29, 2017	Apr. 29, 2017	Jan. 28, 2017	Oct. 29, 2016	Jul. 30, 2016	Apr. 30, 2016	Jan. 23, 2016	Oct. 24, 2015	Jul. 29, 2017	Jul. 30, 2016	Jul. 25, 2015
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 12,133	$ 11,940	$ 11,580	$ 12,352	$ 12,638	$ 12,000	$ 11,927	$ 12,682	$ 48,005	$ 49,247	$ 49,161
Gross margin	7,546	7,518	7,276	7,884	7,975	7,721	7,432	7,832	30,224	30,960	29,681
Operating income	3,034	3,169	2,893	2,877	3,303	2,984	3,294	3,079	11,973	12,660	10,770
Net income	$ 2,424	$ 2,515	$ 2,348	$ 2,322	$ 2,813	$ 2,349	$ 3,147	$ 2,430	$ 9,609	$ 10,739	$ 8,981
Basic (in dollars per share)	$ 0.49	$ 0.50	$ 0.47	$ 0.46	$ 0.56	$ 0.47	$ 0.62	$ 0.48	$ 1.92	$ 2.13	$ 1.76
Diluted (in dollars per share)	0.48	0.50	0.47	0.46	0.56	0.46	0.62	0.48	1.90	2.11	1.75
Cash dividends declared per common share (in dollars per share)	$ 0.29	$ 0.29	$ 0.26	$ 0.26	$ 0.26	$ 0.26	$ 0.21	$ 0.21	$ 1.1	$ 0.94	$ 0.80
Cash and cash equivalents and investments	$ 70,492	$ 67,974	$ 71,845	$ 70,968	$ 65,756	$ 63,512	$ 60,375	$ 59,107	$ 70,492	$ 65,756