FAIR VALUE MEASUREMENTS - OTHER FAIR VALUE DISCLOSURES (Details) - Estimate of Fair Value Measurement - USD ($) $ in Millions	Oct. 31, 2016	Jan. 31, 2016
Term Loans \| Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Term Loans - Fair Value	$ 412	$ 411
1.50% Convertible Senior Notes \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
1.50% Convertible Senior Notes - Fair Value	$ 378	$ 367

Fair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Convertible Security
-URI http://asc.fasb.org/extlink&oid=6509036

Name:	us-gaap_ConvertibleDebtFairValueDisclosures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant