Comprehensive Income - Reclassification Out of Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 26, 2019	Oct. 27, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other income (loss), net	$ 12	$ (19)
Revenue	13,159	13,072
Cost of sales	(4,695)	(4,926)
Operating expenses	(4,885)	(4,341)
Net income (loss)	2,926	3,549
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net income (loss)	9	(5)
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	10	(6)
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	(3)
Cost of sales	1
Operating expenses	2
Net income (loss)	0
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
Cost of sales		0
Operating expenses		(1)
Net income (loss)		0
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	$ (1)	$ 1