Income Taxes (Income Before Provision for Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended
Oct. 27, 2018	Oct. 28, 2017
Income Tax Disclosure [Abstract]
Income before provision for income taxes	$ 3,909	$ 2,962
Provision for income taxes	$ 360	$ 568
Effective tax rate	9.20%	19.20%

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

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