Available-for-Sale Debt Investments and Equity Investments - Additional Information (Details)	9 Months Ended
	Apr. 25, 2020 USD ($) entity	Jul. 27, 2019 USD ($)
Schedule of Investments [Line Items]
Impairment charges of available-for-sale investments, in an unrealized loss position	$ 0
Non-marketable equity securities included in other assets	$ 1,186,000,000	$ 1,113,000,000
Number of variable interest entities required to be consolidated (entity) | entity	0
Investments in privately held companies	$ 1,300,000,000
Funding commitments	344,000,000
Private equity funds | Fair value measured at NAV per share
Schedule of Investments [Line Items]
Non-marketable equity securities included in other assets	700,000,000	$ 600,000,000
Variable Interest Entity, Not Primary Beneficiary
Schedule of Investments [Line Items]
Investments in privately held companies	$ 691,000,000