Fair Value - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	Jan. 23, 2021	Jul. 25, 2020
Assets:
Available-for-sale debt investments:	$ 18,790	$ 17,610
U.S. government securities
Assets:
Available-for-sale debt investments:	2,663	2,685
U.S. government agency securities
Assets:
Available-for-sale debt investments:	168	110
Corporate debt securities
Assets:
Available-for-sale debt investments:	10,786	11,877
Commercial paper
Assets:
Available-for-sale debt investments:	1,730	727
Certificates of deposit
Assets:
Available-for-sale debt investments:	603	176
Fair value, measurements, recurring
Assets:
Marketable equity securities	5	0
Derivative assets	171	191
Total	28,553	27,833
Liabilities:
Derivative liabilities	26	10
Total	26	10
Fair value, measurements, recurring \| U.S. government securities
Assets:
Available-for-sale debt investments:	2,663	2,685
Fair value, measurements, recurring \| U.S. government agency securities
Assets:
Available-for-sale debt investments:	168	110
Fair value, measurements, recurring \| Corporate debt securities
Assets:
Available-for-sale debt investments:	10,786	11,877
Fair value, measurements, recurring \| U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments:	2,840	2,035
Fair value, measurements, recurring \| Commercial paper
Assets:
Available-for-sale debt investments:	1,730	727
Fair value, measurements, recurring \| Certificates of deposit
Assets:
Available-for-sale debt investments:	603	176
Fair value, measurements, recurring \| Money market funds
Assets:
Cash equivalents:	8,515	10,024
Fair value, measurements, recurring \| Corporate debt securities
Assets:
Cash equivalents:	9	8
Fair value, measurements, recurring \| Certificates of deposit
Assets:
Cash equivalents:	161	0
Fair value, measurements, recurring \| Commercial paper
Assets:
Cash equivalents:	902	0
Fair value, measurements, recurring \| Level 1
Assets:
Marketable equity securities	5	0
Derivative assets	0	0
Total	8,520	10,024
Liabilities:
Derivative liabilities	0	0
Total	0	0
Fair value, measurements, recurring \| Level 1 \| U.S. government securities
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 1 \| U.S. government agency securities
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 1 \| Corporate debt securities
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 1 \| U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 1 \| Commercial paper
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 1 \| Certificates of deposit
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 1 \| Money market funds
Assets:
Cash equivalents:	8,515	10,024
Fair value, measurements, recurring \| Level 1 \| Corporate debt securities
Assets:
Cash equivalents:	0	0
Fair value, measurements, recurring \| Level 1 \| Certificates of deposit
Assets:
Cash equivalents:	0	0
Fair value, measurements, recurring \| Level 1 \| Commercial paper
Assets:
Cash equivalents:	0	0
Fair value, measurements, recurring \| Level 2
Assets:
Marketable equity securities	0	0
Derivative assets	165	190
Total	20,027	17,808
Liabilities:
Derivative liabilities	26	10
Total	26	10
Fair value, measurements, recurring \| Level 2 \| U.S. government securities
Assets:
Available-for-sale debt investments:	2,663	2,685
Fair value, measurements, recurring \| Level 2 \| U.S. government agency securities
Assets:
Available-for-sale debt investments:	168	110
Fair value, measurements, recurring \| Level 2 \| Corporate debt securities
Assets:
Available-for-sale debt investments:	10,786	11,877
Fair value, measurements, recurring \| Level 2 \| U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments:	2,840	2,035
Fair value, measurements, recurring \| Level 2 \| Commercial paper
Assets:
Available-for-sale debt investments:	1,730	727
Fair value, measurements, recurring \| Level 2 \| Certificates of deposit
Assets:
Available-for-sale debt investments:	603	176
Fair value, measurements, recurring \| Level 2 \| Money market funds
Assets:
Cash equivalents:	0	0
Fair value, measurements, recurring \| Level 2 \| Corporate debt securities
Assets:
Cash equivalents:	9	8
Fair value, measurements, recurring \| Level 2 \| Certificates of deposit
Assets:
Cash equivalents:	161	0
Fair value, measurements, recurring \| Level 2 \| Commercial paper
Assets:
Cash equivalents:	902	0
Fair value, measurements, recurring \| Level 3
Assets:
Marketable equity securities	0	0
Derivative assets	6	1
Total	6	1
Liabilities:
Derivative liabilities	0	0
Total	0	0
Fair value, measurements, recurring \| Level 3 \| U.S. government securities
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 3 \| U.S. government agency securities
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 3 \| Corporate debt securities
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 3 \| U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 3 \| Commercial paper
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 3 \| Certificates of deposit
Assets:
Available-for-sale debt investments:	0	0
Fair value, measurements, recurring \| Level 3 \| Money market funds
Assets:
Cash equivalents:	0	0
Fair value, measurements, recurring \| Level 3 \| Corporate debt securities
Assets:
Cash equivalents:	0	0
Fair value, measurements, recurring \| Level 3 \| Certificates of deposit
Assets:
Cash equivalents:	0	0
Fair value, measurements, recurring \| Level 3 \| Commercial paper
Assets:
Cash equivalents:	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value of financial and nonfinancial obligations.

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