Segments and Disaggregated Revenue (Operating Income by Segment, Interest, Net, and Unrealized (Gains) and Losses) (Details) - USD ($) $ in Millions	3 Months Ended
Apr. 30, 2020	Apr. 30, 2019
Segment Reporting Information [Line Items]
Operating income	$ 5,224	$ 4,945
Interest, net	549	625
Other (gains) and losses	(721)	(837)
Income before income taxes	5,396	5,157
Walmart U.S.
Segment Reporting Information [Line Items]
Operating income	4,302	4,142
Walmart International
Segment Reporting Information [Line Items]
Operating income	806	738
Sam's Club
Segment Reporting Information [Line Items]
Operating income	494	451
Corporate and support
Segment Reporting Information [Line Items]
Operating income	$ (378)	$ (386)

Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(1)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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- Definition

The net amount of operating interest income (expense).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.10)
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The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7)
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The net result for the period of deducting operating expenses from operating revenues.

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No definition available.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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