Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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- Definition

Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
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://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-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

- Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

Name:	us-gaap_RepaymentsOfLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying amount of collateralized debt obligations with maturities initially due after one year or beyond the operating cycle, if longer, excluding the current portion. Obligations include, but not limited to, mortgage loans, chattel loans, and other borrowings secured by assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

+ Details

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

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19

-Subparagraph a

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(a))

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.(a),16(a)(1))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Subparagraph a(1)

-Article 7

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13

-Subparagraph 2, 3

-Article 9

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Carrying value of property collateralizing long-term debt

+ References

No definition available.

+ Details

Name:	wmt_CarryingValueOfPropertyCollateralizingLongTermDebt
Namespace Prefix:	wmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of financial institutions committing to lend funds under lines of credit

+ References

No definition available.

+ Details

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Namespace Prefix:	wmt_
Data Type:	xbrli:integerItemType
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Period Type:	duration

Long-term Debt (Details)	12 Months Ended			0 Months Ended							0 Months Ended						12 Months Ended
Long-term Debt (Details)	Jan. 31, 2015 USD ($) Financial_institution	Jan. 31, 2014 USD ($) Financial_institution	Jan. 31, 2013 USD ($)	Aug. 05, 2013 Debt Securities [Member] JPY (¥)	Apr. 15, 2013 Debt Securities [Member] 4.250% Debt, Due 2013 [Domain] [Domain] USD ($)	Feb. 03, 2014 Debt Securities [Member] 3.000% Debt, Due 2014 [Domain] USD ($)	Apr. 14, 2014 Debt Securities [Member] 1.625% Debt, Due 2014 [Domain] USD ($)	May 15, 2014 Debt Securities [Member] 3.200% Debt, Due 2014 [Domain] USD ($)	May 01, 2013 Debt Securities [Member] 4.550% Debt, Due 2013 [Domain] USD ($)	May 01, 2013 Debt Securities [Member] 4.550% Debt, Due 2013 [Domain]	Jun. 01, 2013 Debt Securities [Member] 7.250% Debt, Due 2013 [Domain] USD ($)	Aug. 05, 2013 Debt Securities [Member] 2.010% Debt, Due 2013 [Domain] JPY (¥)	Oct. 25, 2013 Debt Securities [Member] 0.750% Debt, Due 2013 [Domain] USD ($)	Aug. 06, 2014 JAPAN Debt Securities [Member] JPY (¥)	Jan. 31, 2015 Put Option [Member] USD ($)	Jan. 31, 2014 Put Option [Member] USD ($)	Jan. 31, 2015 Minimum	Jan. 31, 2015 Maximum
Debt Instrument [Line Items]
Short-term borrowings	$ 1,592,000,000us-gaap_ShortTermBorrowings	$ 7,670,000,000us-gaap_ShortTermBorrowings
Number Of Financial Institutions Committing To Lend Funds Under Lines Of Credit	23	24
Available	15,000,000,000	15,400,000,000
Debt Instrument, Basis Spread on Variable Rate																	10.00%	75.00%
Line of Credit Facility, Commitment Fee Percentage																	1.50%	4.00%
Letters of Credit Outstanding, Amount	4,600,000,000	4,700,000,000
Secured Long-term Debt, Noncurrent	139,000,000us-gaap_SecuredLongTermDebt	572,000,000us-gaap_SecuredLongTermDebt
Carrying Value Of Property Collateralizing Long Term Debt	19,000,000	471,000,000
Long-term Debt, Gross															500,000,000	500,000,000
Interest Rate					4.25%	3.00%	1.625%	3.20%		4.55%	7.25%	2.01%	0.75%
Payments of long-term debt	$ 3,904,000,000us-gaap_RepaymentsOfLongTermDebt	$ 4,968,000,000us-gaap_RepaymentsOfLongTermDebt	$ 1,478,000,000us-gaap_RepaymentsOfLongTermDebt	¥ 50,000,000,000	$ 1,000,000,000	$ 500,000,000	$ 1,000,000,000	$ 1,000,000,000	$ 1,500,000,000		$ 500,000,000	¥ 25,000,000,000	$ 750,000,000	¥ 100,000,000,000