PENSION AND OTHER POST-EMPLOYMENT BENEFITS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Pension Benefits
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Interest cost	$ 2.4	$ 2.5	$ 4.9	$ 5.0
Expected return on plan assets	(4.0)	(4.6)	(8.0)	(9.2)
Amortization of prior service credit	0.0	0.0	0.0	0.0
Recognized actuarial loss	0.2	0.4	0.3	0.7
Pension settlement charge	0.5	4.6	0.6	4.6
Net periodic benefit (income) cost	(0.9)	2.9	(2.2)	1.1
Other Benefits
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Interest cost	0.1	0.0	0.2	0.1
Expected return on plan assets	0.0	0.0	0.0	0.0
Amortization of prior service credit	(0.2)	(0.2)	(0.4)	(0.4)
Recognized actuarial loss	0.0	0.0	0.0	0.0
Pension settlement charge	0.0	0.0	0.0	0.0
Net periodic benefit (income) cost	$ (0.1)	$ (0.2)	$ (0.2)	$ (0.3)