Taxes (Schedule of Income Before Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Taxes [Line Items]
Income before income taxes, U.S.	$ 10,722	$ 15,680	$ 16,685
Income before income taxes, non-U.S.	4,401	4,817	4,953
Income before income taxes	$ 15,123	$ 20,497	$ 21,638

The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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 portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.

+ References

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- Definition

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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- Definition

Taxes [Line Items]

+ References

No definition available.

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