Derivative Instruments - Consolidated Statements of Operations of Derivative Instruments (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 26, 2019	Oct. 27, 2018
Derivative [Line Items]
Revenue	$ 13,159	$ 13,072
Cost of sales	4,695	4,926
Operating expenses	4,885	4,341
Interest and other income (loss), net	107	104
Total gains (losses)	1	0
Interest rate derivatives
Derivative [Line Items]
Hedged items	(21)	9
Derivatives designated as hedging instruments	22	(9)
Foreign currency derivatives
Derivative [Line Items]
Amount of gains (losses) reclassified from AOCI to income	0
Amount of gains (losses) reclassified from AOCI to income		0
Revenue
Derivative [Line Items]
Total gains (losses)	(3)	1
Revenue | Interest rate derivatives
Derivative [Line Items]
Hedged items	0	0
Derivatives designated as hedging instruments	0	0
Revenue | Foreign currency derivatives
Derivative [Line Items]
Amount of gains (losses) reclassified from AOCI to income	(3)
Amount of gains (losses) reclassified from AOCI to income		1
Cost of sales
Derivative [Line Items]
Total gains (losses)	1	0
Cost of sales | Interest rate derivatives
Derivative [Line Items]
Hedged items	0	0
Derivatives designated as hedging instruments	0	0
Cost of sales | Foreign currency derivatives
Derivative [Line Items]
Amount of gains (losses) reclassified from AOCI to income	1
Amount of gains (losses) reclassified from AOCI to income		0
Operating expenses
Derivative [Line Items]
Total gains (losses)	2	(1)
Operating expenses | Interest rate derivatives
Derivative [Line Items]
Hedged items	0	0
Derivatives designated as hedging instruments	0	0
Operating expenses | Foreign currency derivatives
Derivative [Line Items]
Amount of gains (losses) reclassified from AOCI to income	$ 2
Amount of gains (losses) reclassified from AOCI to income		$ (1)