Summary of Significant Accounting Policies (Schedule of Goodwill) (Details) - USD ($) $ in Millions	12 Months Ended
Jan. 31, 2017	Jan. 31, 2016
Goodwill [Roll Forward]
Goodwill	$ 16,695	$ 18,102
Changes in currency translation and other	(1,433)	(1,412)
Acquisitions	1,775	5
Goodwill	17,037	16,695
Walmart U.S.
Goodwill [Roll Forward]
Goodwill	461	461
Changes in currency translation and other	0	0
Acquisitions	1,775	0
Goodwill	2,236	461
Walmart International
Goodwill [Roll Forward]
Goodwill	15,921	17,328
Changes in currency translation and other	(1,433)	(1,412)
Acquisitions	0	5
Goodwill	14,488	15,921
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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975

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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.

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- Definition

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

+ References

No definition available.

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