Comprehensive Income (Loss) (Reclassification Out of Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 27, 2019	Apr. 28, 2018	Apr. 27, 2019	Apr. 28, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Revenue	$ 12,958	$ 12,463	$ 38,476	$ 36,486
NET INCOME (LOSS)	3,044	2,691	9,415	(3,693)
Total amounts reclassified out of AOCI	(8)	45	(21)	162
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	(7)	17	(18)	108
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]
Operating expenses	0	21	(1)	45
NET INCOME (LOSS)	0	28	1	59
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)	0	(4)	0
Operating expenses	0	0	0	5
Product
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Revenue	9,722	9,304	28,885	27,067
Product | 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)	0	0	0
Service
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Revenue	3,236	3,159	9,591	9,419
Service | 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	0	3	0
Cost of sales	$ 0	$ 7	$ (1)	$ 14