Operating Income by Segment, Interest, Net, and Unrealized (Gains) and Losses (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Segment Reporting Information [Line Items]
Operating income	$ 5,583	$ 5,750	$ 10,528	$ 10,904
Interest, net	585	503	1,210	990
Other (gains) and losses	85	4,849	(752)	6,694
Income before income taxes	4,913	398	10,070	3,220
Walmart U.S.
Segment Reporting Information [Line Items]
Operating income	4,659	4,479	8,801	8,406
Walmart International
Segment Reporting Information [Line Items]
Operating income	893	1,269	1,631	2,534
Sam's Club
Segment Reporting Information [Line Items]
Operating income	480	402	931	727
Corporate and support
Segment Reporting Information [Line Items]
Operating income	$ (449)	$ (400)	$ (835)	$ (763)

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.

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-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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The net amount of operating interest income (expense).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
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-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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