Income Taxes - Differences between income taxes calculated using the federal statutory income tax rate and the provision for income taxes from continuing operations (Details) - USD ($) $ in Millions	12 Months Ended
Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2019
Operating Loss Carryforwards [Line Items]
Income before income taxes	$ 2,556	$ 2,198	$ 1,881
U.S. federal statutory rate	21.00%	21.00%	21.00%
Statutory federal income tax	$ 537	$ 462	$ 395
State income tax, net of federal benefit	87	25	50
Federal research and experimentation credits	(70)	(54)	(48)
Share-based compensation	38	22	15
Federal excess tax benefits related to share-based compensation	(126)	(90)	(120)
Effects of non-U.S. operations	4	13	13
Other, net	3	(17)	5
Total provision for income taxes	494	372	324
Domestic Country
Operating Loss Carryforwards [Line Items]
Federal excess tax benefits related to share-based compensation	$ (105)	$ (79)	$ (106)

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to expense for award under share-based payment arrangement. Excludes expense determined to be nondeductible upon grant or after for award under share-based payment arrangement.

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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to foreign income tax expense (benefit).

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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Amount of reported income tax expense (benefit) in excess of (less than) expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to nondeductible expense for award under share-based payment arrangement. Includes, but is not limited to, expense determined to be nondeductible upon grant or after for award under share-based payment arrangement.

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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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