Comprehensive Income (Loss) (Reclassification Out of Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jan. 26, 2019	Jan. 27, 2018	Jan. 26, 2019	Jan. 27, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Revenue	$ 12,446	$ 11,887	$ 25,518	$ 24,023
NET INCOME (LOSS)	2,822	(8,778)	6,371	(6,384)
Total amounts reclassified out of AOCI	(8)	72	(13)	117
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	(5)	58	(11)	91
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	14	(1)	24
NET INCOME (LOSS)	1	18	1	31
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	(4)	0	(3)	0
Operating expenses	0	4	0	5
Product
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Revenue	9,273	8,709	19,163	17,763
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	1	0
Service
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Revenue	3,173	3,178	6,355	6,260
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	2	0
Cost of sales	$ (1)	$ 4	$ (1)	$ 7

The aggregate cost of goods produced and sold and services rendered during the reporting period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount after tax of reclassification adjustments of other comprehensive income (loss).

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