Income Taxes - Sources of income from continuing operations (Details) - USD ($) $ in Millions	12 Months Ended
Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Income Tax Disclosure [Abstract]
United States	$ 1,464	$ 1,362	$ 1,205
Foreign	39	5	(2)
Income from continuing operations before income taxes	$ 1,503	$ 1,367	$ 1,203

The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(1)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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- Definition

The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.

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- Definition

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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- References

No definition available.

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