PENSION AND POST-RETIREMENT PLANS - STATUS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pensions
Change in Benefit Obligation:
Benefit obligation at beginning of year	$ 220.2	$ 237.4
Service cost	3.9	3.3	$ 3.3
Interest cost	9.7	9.5	9.4
Actuarial loss (gain)	4.2	(17.9)
Benefits paid, net of subsidies received	(11.1)	(10.9)
Expenses paid	(1.5)	(1.2)
Benefit obligation at end of year	225.4	220.2	237.4
Changes in plan assets:
Balance at the beginning of the period	168.9	178.9
Actual return on plan assets	15.0	(2.6)
Employer contribution	7.5	4.7	6.5
Benefits paid, net of subsidies received	(11.1)	(10.9)
Expenses paid	(1.5)	(1.2)
Balance at the end of the period	178.8	168.9	178.9
Funded Status and Recognized Liability	(46.6)	(51.3)
Other Post-retirement Benefits
Change in Benefit Obligation:
Benefit obligation at beginning of year	60.5	62.6
Service cost	1.5	1.5	1.1
Interest cost	2.7	2.5	2.6
Plan participants' contributions	1.0	0.9
Actuarial loss (gain)	1.9	(3.1)
Benefits paid, net of subsidies received	(4.0)	(3.9)
Benefit obligation at end of year	63.6	60.5	$ 62.6
Changes in plan assets:
Plan participants' contributions	1.0	0.9
Employer contribution	3.0	3.0
Benefits paid, net of subsidies received	(4.0)	(3.9)
Funded Status and Recognized Liability	$ (63.6)	$ (60.5)