FAIR VALUE MEASUREMENTS - OTHER FAIR VALUE DISCLOSURES (Details) - Estimate of Fair Value Measurement - USD ($) $ in Millions |
Apr. 30, 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 | $ 361 | $ 367 |