FAIR VALUE MEASUREMENTS - OTHER FAIR VALUE DISCLOSURES (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Apr. 30, 2020	Jan. 31, 2020
Contingent consideration
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Weighted Average Discount Rate	6.60%
Term Loans | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Term Loans - Fair Value	$ 406	$ 417
1.50% Convertible Senior Notes | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
1.50% Convertible Senior Notes - Fair Value	386	438
2017 Revolving Credit Facility | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Term Loans - Fair Value	$ 190	$ 45
Contingent consideration
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Weighted Average Discount Rate	4.80%
Option to Acquire Noncontrolling Interests
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair Value Measurement Input - Discount Rate	11.00%	9.00%
Minimum | Contingent consideration
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair Value Measurement Input - Discount Rate	6.40%	4.30%
Minimum | Contingent consideration
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair Value Measurement Input - Discount Rate	3.20%	2.10%
Maximum | Contingent consideration
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair Value Measurement Input - Discount Rate	6.80%	4.90%
Maximum | Contingent consideration
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair Value Measurement Input - Discount Rate	6.70%	4.90%