Short-Term Borrowings And Long-Term Debt (Information On Short-Term Borrowings And Interest Rates) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Debt Disclosure [Abstract]
Maximum amount outstanding at any month-end	$ 8,740	$ 9,594	$ 9,282
Average daily short-term borrowings	$ 6,007	$ 6,040	$ 4,020
Weighted-average interest rate	0.10%	0.10%	0.20%

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period.

+ References

No definition available.

+ Details

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- Definition

For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, maximum month-end borrowings during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Industry Guide

-Number 3

-Section VII

-Subsection 2

+ Details

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- Definition

Reflects the calculation as of the balance sheet date of the average interest rate weighted by the amount of short-term debt outstanding by type or by instrument at that time.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19

-Subparagraph b

-Article 5

+ Details

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