Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3291-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

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Long-term Debt Schedule of Debt Maturities (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 21, 2017	Apr. 05, 2017
Debt Instrument [Line Items]
Repayments of Long-term Debt	$ 1,513	$ 2,013
Unsecured debt
Debt Instrument [Line Items]
Repayments of Long-term Debt	1,500
Unsecured debt \| 5.375% Fixed Rate Debt, Due 2017 [Member]
Debt Instrument [Line Items]
Principal Amount				$ 1,000
Interest Rate				5.375%
Repayments of Long-term Debt	1,000
Unsecured debt \| 1.000% Fixed Rate Debt, Due 2017 [Member]
Debt Instrument [Line Items]
Principal Amount			$ 500
Interest Rate			1.00%
Repayments of Long-term Debt	$ 500