Available-for-Sale Debt and Equity Investments - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 23, 2021	Jan. 25, 2020	Jan. 23, 2021	Jan. 25, 2020	Jul. 25, 2020
Schedule of Investments [Line Items]
Unrealized gains on equity securities	$ 4	$ 3	$ 4	$ 3
Net gain on non-marketable equity securities measured using the measurement alternative	3	$ 3	4	$ 3
Investments in privately held companies	1,300		1,300		$ 1,300
Funding commitments	300		300
Variable Interest Entity, Not Primary Beneficiary
Schedule of Investments [Line Items]
Investments in privately held companies	700		700
Private equity funds | Fair value measured at NAV per share
Schedule of Investments [Line Items]
Equity interests held in certain private equity funds	$ 700		$ 700		$ 700