Fair Value - Assets and Liabilities Measured At Fair Value On Recurring Basis (Details) - USD ($) $ in Millions	Jul. 31, 2021	Jul. 25, 2020
Assets:
Available-for-sale debt investments	$ 15,206	$ 17,610
U.S. government securities
Assets:
Available-for-sale debt investments	1,794	2,685
U.S. government agency securities
Assets:
Available-for-sale debt investments	152	110
Corporate debt securities
Assets:
Available-for-sale debt investments	8,910	11,877
Non-U.S. government and agency securities
Assets:
Available-for-sale debt investments	3
Commercial paper
Assets:
Available-for-sale debt investments	1,190	727
Certificates of deposit
Assets:
Available-for-sale debt investments	295	176
Recurring
Assets:
Marketable equity securities	137	0
Derivative assets	126	191
Total	22,327	27,496
Liabilities:
Derivative liabilities	20	10
Total	20	10
Recurring \| Money market funds
Assets:
Money market funds	750	0
Recurring \| U.S. government securities
Assets:
Available-for-sale debt investments	1,794	2,685
Recurring \| U.S. government agency securities
Assets:
Available-for-sale debt investments	152	110
Recurring \| Corporate debt securities
Assets:
Available-for-sale debt investments	8,910	11,877
Recurring \| U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments	2,862	2,035
Recurring \| Non-U.S. government and agency securities
Assets:
Available-for-sale debt investments	3	0
Recurring \| Commercial paper
Assets:
Available-for-sale debt investments	1,190	727
Recurring \| Certificates of deposit
Assets:
Available-for-sale debt investments	295	176
Recurring \| Money market funds
Assets:
Cash equivalents	5,694	9,687
Recurring \| Commercial paper
Assets:
Cash equivalents	114	0
Recurring \| U.S. government securities
Assets:
Cash equivalents	300	0
Recurring \| Corporate debt securities
Assets:
Cash equivalents	0	8
Recurring \| Level 1
Assets:
Marketable equity securities	137	0
Derivative assets	0	0
Total	6,581	9,687
Liabilities:
Derivative liabilities	0	0
Total	0	0
Recurring \| Level 1 \| Money market funds
Assets:
Money market funds	750	0
Recurring \| Level 1 \| U.S. government securities
Assets:
Available-for-sale debt investments	0	0
Recurring \| Level 1 \| U.S. government agency securities
Assets:
Available-for-sale debt investments	0	0
Recurring \| Level 1 \| Corporate debt securities
Assets:
Available-for-sale debt investments	0	0
Recurring \| Level 1 \| U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments	0	0
Recurring \| Level 1 \| Non-U.S. government and agency securities
Assets:
Available-for-sale debt investments	0	0
Recurring \| Level 1 \| Commercial paper
Assets:
Available-for-sale debt investments	0	0
Recurring \| Level 1 \| Certificates of deposit
Assets:
Available-for-sale debt investments	0	0
Recurring \| Level 1 \| Money market funds
Assets:
Cash equivalents	5,694	9,687
Recurring \| Level 1 \| Commercial paper
Assets:
Cash equivalents	0	0
Recurring \| Level 1 \| U.S. government securities
Assets:
Cash equivalents	0	0
Recurring \| Level 1 \| Corporate debt securities
Assets:
Cash equivalents	0	0
Recurring \| Level 2
Assets:
Marketable equity securities	0	0
Derivative assets	126	190
Total	15,746	17,808
Liabilities:
Derivative liabilities	20	10
Total	20	10
Recurring \| Level 2 \| Money market funds
Assets:
Money market funds	0	0
Recurring \| Level 2 \| U.S. government securities
Assets:
Available-for-sale debt investments	1,794	2,685
Recurring \| Level 2 \| U.S. government agency securities
Assets:
Available-for-sale debt investments	152	110
Recurring \| Level 2 \| Corporate debt securities
Assets:
Available-for-sale debt investments	8,910	11,877
Recurring \| Level 2 \| U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments	2,862	2,035
Recurring \| Level 2 \| Non-U.S. government and agency securities
Assets:
Available-for-sale debt investments	3	0
Recurring \| Level 2 \| Commercial paper
Assets:
Available-for-sale debt investments	1,190	727
Recurring \| Level 2 \| Certificates of deposit
Assets:
Available-for-sale debt investments	295	176
Recurring \| Level 2 \| Money market funds
Assets:
Cash equivalents	0	0
Recurring \| Level 2 \| Commercial paper
Assets:
Cash equivalents	114	0
Recurring \| Level 2 \| U.S. government securities
Assets:
Cash equivalents	300	0
Recurring \| Level 2 \| Corporate debt securities
Assets:
Cash equivalents	$ 0	8
Recurring \| Level 3
Assets:
Marketable equity securities		0
Derivative assets		1
Total		1
Liabilities:
Derivative liabilities		0
Total		0
Recurring \| Level 3 \| Money market funds
Assets:
Money market funds		0
Recurring \| Level 3 \| U.S. government securities
Assets:
Available-for-sale debt investments		0
Recurring \| Level 3 \| U.S. government agency securities
Assets:
Available-for-sale debt investments		0
Recurring \| Level 3 \| Corporate debt securities
Assets:
Available-for-sale debt investments		0
Recurring \| Level 3 \| U.S. agency mortgage-backed securities
Assets:
Available-for-sale debt investments		0
Recurring \| Level 3 \| Non-U.S. government and agency securities
Assets:
Available-for-sale debt investments		0
Recurring \| Level 3 \| Commercial paper
Assets:
Available-for-sale debt investments		0
Recurring \| Level 3 \| Certificates of deposit
Assets:
Available-for-sale debt investments		0
Recurring \| Level 3 \| Money market funds
Assets:
Cash equivalents		0
Recurring \| Level 3 \| Commercial paper
Assets:
Cash equivalents		0
Recurring \| Level 3 \| U.S. government securities
Assets:
Cash equivalents		0
Recurring \| Level 3 \| Corporate debt securities
Assets:
Cash equivalents		$ 0

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

+ Details

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

No definition available.

+ Details

Name:	us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226052-175313

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=123594938&loc=d3e13433-108611

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

+ Details

Name:	us-gaap_DerivativeAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or 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 liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=123594938&loc=d3e13433-108611

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226052-175313

+ Details

Name:	us-gaap_DerivativeLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=123594786&loc=SL75136599-209740

+ Details

Name:	us-gaap_EquitySecuritiesFvNi
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of financial and nonfinancial obligations.

+ References

+ Details

Name:	us-gaap_LiabilitiesFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_LiabilitiesFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value portion of other assets.

+ References

No definition available.

+ Details

Name:	us-gaap_OtherAssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommercialPaperMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=us-gaap_CommercialPaperMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: