DEBT - Senior Term Loan Facility (Details) - Secured debt - HDS (Debt Issuer) - Credit facility $ in Millions	3 Months Ended
	Apr. 30, 2017 USD ($)	Apr. 18, 2017 USD ($)
Term Loan Facility
DEBT
Aggregate principal amount	$ 1,392
Term B-1 Loan Facility due 2021
DEBT
Aggregate principal amount		$ 842
Amortization of debt, aggregate annual amounts as a percentage of original principal amount (as a percent)	1.00%
Term B-2 Loan Facility due 2023
DEBT
Amortization of debt, aggregate annual amounts as a percentage of original principal amount (as a percent)	1.00%
LIBOR | Term B-1 Loan Facility due 2021
DEBT
Percentage added to reference rate (as a percent)	2.75%
LIBOR | Term B-2 Loan Facility due 2023
DEBT
Percentage added to reference rate (as a percent)	2.75%
Base | Term B-1 Loan Facility due 2021
DEBT
Percentage added to reference rate (as a percent)	1.75%
Base | Term B-2 Loan Facility due 2023
DEBT
Percentage added to reference rate (as a percent)	1.75%
Minimum | LIBOR | Term B-2 Loan Facility due 2023
DEBT
Percentage added to reference rate (as a percent)	2.50%
Maximum | Term B-2 Loan Facility due 2023
DEBT
Leverage ratio	3.0