Taxes (Schedule of Deferred Tax Classification in the Balance Sheet) (Details) - USD ($) $ in Millions	Jan. 31, 2021	Jan. 31, 2020
Liabilities:
Net deferred tax liabilities	$ 6,609	$ 4,290
Other long-term assets [Member]
ASSETS
Other long-term assets	1,836	1,914
Deferred income taxes and other [Member]
Liabilities:
Net deferred tax liabilities	$ 8,445	$ 6,204

Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=120406818&loc=d3e31931-109318

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant