Derivative Instruments - Consolidated Statements of Operations of Derivative Instruments (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Apr. 25, 2020	Apr. 27, 2019	Apr. 25, 2020	Apr. 27, 2019
Derivative [Line Items]
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
Interest and other income (loss), net	30	102	291	338
Revenue
Derivative [Line Items]
Total gains (losses)	1	0	(4)	3
Revenue \| Interest rate derivatives
Derivative [Line Items]
Hedged items	0	0	0	0
Derivatives designated as hedging instruments	0	0	0	0
Revenue \| Foreign currency derivatives
Derivative [Line Items]
Amount of gains (losses) reclassified from AOCI to income	1		(4)
Amount of gains (losses) reclassified from AOCI to income		0		3
Cost of sales
Derivative [Line Items]
Total gains (losses)	0	0	1	(1)
Cost of sales \| Interest rate derivatives
Derivative [Line Items]
Hedged items	0	0	0	0
Derivatives designated as hedging instruments	0	0	0	0
Cost of sales \| Foreign currency derivatives
Derivative [Line Items]
Amount of gains (losses) reclassified from AOCI to income	0		1
Amount of gains (losses) reclassified from AOCI to income		0		(1)
Operating expenses
Derivative [Line Items]
Total gains (losses)	0	0	2	(1)
Operating expenses \| Interest rate derivatives
Derivative [Line Items]
Hedged items	0	0	0	0
Derivatives designated as hedging instruments	0	0	0	0
Operating expenses \| Foreign currency derivatives
Derivative [Line Items]
Amount of gains (losses) reclassified from AOCI to income	0		2
Amount of gains (losses) reclassified from AOCI to income		0		(1)
Interest and other income (loss), net
Derivative [Line Items]
Total gains (losses)	2	2	4	5
Interest and other income (loss), net \| Interest rate derivatives
Derivative [Line Items]
Hedged items	(87)	(31)	(101)	(83)
Derivatives designated as hedging instruments	89	33	105	88
Interest and other income (loss), net \| Foreign currency derivatives
Derivative [Line Items]
Amount of gains (losses) reclassified from AOCI to income	$ 0		$ 0
Amount of gains (losses) reclassified from AOCI to income		$ 0		$ 0

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount before tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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