Summary of Significant Accounting Policies (Schedule of Goodwill) (Details) - USD ($) $ in Millions	12 Months Ended
Jan. 31, 2019	Jan. 31, 2018
Goodwill [Roll Forward]
Goodwill	$ 18,242	$ 17,037
Changes in currency translation and other	(743)	996
Acquisitions	13,682	209
Goodwill	31,181	18,242
Walmart U.S.
Goodwill [Roll Forward]
Goodwill	2,445	2,236
Changes in currency translation and other	0	0
Acquisitions	107	209
Goodwill	2,552	2,445
Walmart International
Goodwill [Roll Forward]
Goodwill	15,484	14,488
Changes in currency translation and other	(743)	996
Acquisitions	13,575	0
Goodwill	28,316	15,484
Sam's Club
Goodwill [Roll Forward]
Goodwill	313	313
Changes in currency translation and other	0	0
Acquisitions	0	0
Goodwill	$ 313	$ 313

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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