Comprehensive Income - Reclassification Out of Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 25, 2020	Apr. 27, 2019	Apr. 25, 2020	Apr. 27, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other income (loss), net	$ (58)	$ (18)	$ 24	$ (10)
Revenue	11,983	12,958	37,147	38,476
Cost of sales	(4,212)	(4,785)	(13,148)	(14,384)
Operating expenses	(4,357)	(4,660)	(13,626)	(13,563)
Net income (loss)	2,774	3,044	8,578	9,415
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net income (loss)	0	(8)	17	(21)
Reclassification out of Accumulated Other Comprehensive Income | Net unrealized gains and losses on available-for-sale investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other income (loss), net	(1)	(7)	20	(18)
Reclassification out of Accumulated Other Comprehensive Income | Net unrealized gains and losses on cash flow hedging instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Revenue	1		(4)
Cost of sales	0		1
Operating expenses	0		2
Net income (loss)	1		(1)
Reclassification out of Accumulated Other Comprehensive Income | Net unrealized gains and losses on cash flow hedging instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Revenue		0		3
Cost of sales		0		(1)
Operating expenses		0		(1)
Net income (loss)		0		1
Reclassification out of Accumulated Other Comprehensive Income | Cumulative translation adjustment and actuarial gains and losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other income (loss), net	$ 0	$ (1)	$ (2)	$ (4)