Segment Information and Major Customers - Summary of Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jul. 25, 2020	Apr. 25, 2020	Jan. 25, 2020	Oct. 26, 2019	Jul. 27, 2019	Apr. 27, 2019	Jan. 26, 2019	Oct. 27, 2018	Jul. 25, 2020	Jul. 27, 2019	Jul. 28, 2018
Segment Reporting Information [Line Items]
Revenue	$ 12,154	$ 11,983	$ 12,005	$ 13,159	$ 13,428	$ 12,958	$ 12,446	$ 13,072	$ 49,301	$ 51,904	$ 49,330
Gross margin	$ 7,684	$ 7,771	$ 7,764	$ 8,464	$ 8,574	$ 8,173	$ 7,773	$ 8,146	31,683	32,666	30,606
Operating Segments
Segment Reporting Information [Line Items]
Gross margin									32,538	33,479	31,463
Operating Segments | Americas
Segment Reporting Information [Line Items]
Revenue									29,291	30,927	29,070
Gross margin									19,547	20,338	18,792
Operating Segments | EMEA
Segment Reporting Information [Line Items]
Revenue									12,659	13,100	12,425
Gross margin									8,304	8,457	7,945
Operating Segments | APJC
Segment Reporting Information [Line Items]
Revenue									7,352	7,877	7,834
Gross margin									4,688	4,683	4,726
Unallocated corporate items
Segment Reporting Information [Line Items]
Gross margin									$ (855)	$ (813)	$ (857)