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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

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