Face (par) amount of debt instrument at time of issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

[Line Items] for Schedule of Fiscal Year 2020 Debt Issuances [Table]

+ References

No definition available.

+ Details

Name:	wmt_ScheduleofFiscalYear2020DebtIssuancesLineItems
Namespace Prefix:	wmt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wmt_A2.850DebtIssuanceDue2024Domain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wmt_A3.050DebtIssuanceDue2026Domain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wmt_A3.250DebtIssuanceDue2029Domain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=wmt_VariousMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Short-term Borrowings and Long-term Debt Schedule of Fiscal Year 2020 Debt Issuances (Details) - USD ($) $ in Millions		6 Months Ended
	Apr. 23, 2019	Jul. 31, 2019	Jul. 31, 2018
Schedule of Fiscal Year 2020 Debt Issuances [Line Items]
Proceeds from Issuance of Long-term Debt		$ 4,020	$ 15,851
Unsecured Debt [Member] \| 2.850% Debt Issuance, Due 2024 [Member]
Schedule of Fiscal Year 2020 Debt Issuances [Line Items]
Debt Instrument, Face Amount	$ 1,500
Debt Instrument, Interest Rate, Stated Percentage	2.85%
Proceeds from Issuance of Long-term Debt	$ 1,493
Unsecured Debt [Member] \| 3.050% Debt Issuance, Due 2026 [Member]
Schedule of Fiscal Year 2020 Debt Issuances [Line Items]
Debt Instrument, Face Amount	$ 1,250
Debt Instrument, Interest Rate, Stated Percentage	3.05%
Proceeds from Issuance of Long-term Debt	$ 1,242
Unsecured Debt [Member] \| 3.250% Debt Issuance, Due 2029 [Member]
Schedule of Fiscal Year 2020 Debt Issuances [Line Items]
Debt Instrument, Face Amount	$ 1,250
Debt Instrument, Interest Rate, Stated Percentage	3.25%
Proceeds from Issuance of Long-term Debt	$ 1,243
Unsecured Debt [Member] \| Various [Member]
Schedule of Fiscal Year 2020 Debt Issuances [Line Items]
Debt Instrument, Face Amount		42
Proceeds from Issuance of Long-term Debt		$ 42