PENSION AND OTHER POST-EMPLOYMENT BENEFITS (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension Benefits
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Expected administrative expenses	$ 0.4	$ 0.2
Interest cost	2.5	2.5
Expected return on plan assets	(4.0)	(4.6)
Amortization of prior service credit	0.0	0.0
Recognized actuarial loss (gain)	0.1	0.4
Pension settlement charge	0.2	0.0
Net periodic benefit income	(0.8)	(1.5)
Other Benefits
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Expected administrative expenses	0.0	0.0
Interest cost	0.1	0.0
Expected return on plan assets	0.0	0.0
Amortization of prior service credit	(0.2)	(0.2)
Recognized actuarial loss (gain)	0.0	0.0
Pension settlement charge	0.0	0.0
Net periodic benefit income	$ (0.1)	$ (0.2)