EMPLOYEE BENEFITS - Schedule of Estimated Future Benefit Payments Expected to be Paid (Details) $ in Millions	Dec. 31, 2015 USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected future payments in 2016	$ 33.5
Defined benefit plan, expected future payment in 2017	29.6
Defined benefit plan, expected future payment in 2018	28.8
Defined benefit plan, expected future payment 2019	28.9
Defined benefit plan, expected future payments 2020	29.2
Defined benefit plan, expected future payments years 2021-2025	138.0
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected future payments in 2016	1.5
Defined benefit plan, expected future payment in 2017	2.0
Defined benefit plan, expected future payment in 2018	2.5
Defined benefit plan, expected future payment 2019	2.9
Defined benefit plan, expected future payments 2020	3.3
Defined benefit plan, expected future payments years 2021-2025	$ 19.0