Fair Value - Additional Information (Details) - USD ($) $ in Millions	Jul. 27, 2019	Jul. 28, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes, carrying value	$ 20,473	$ 25,569
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long term loan receivables and financed service contracts and others carrying value	3,700	3,600
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes, fair value	22,100	26,400
Senior notes, carrying value	$ 20,500	$ 25,600