PENSIONS AND OTHER POSTRETIREMENT BENEFITS PENSION AND OTHER POSTRETIREMENT BENEFITS (Obligations and Funded Status) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 3.7	$ 3.8
Non-current liabilities	(311.5)	(248.7)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligations - beginning of year	905.7	973.1
Service cost (excluding expense)	17.3	18.7	$ 17.1
Interest cost	34.9	30.3	30.5
Plan Amendments	0.0	2.2
Actuarial (gain) loss	111.8	(57.0)
Benefits paid	(62.2)	(60.7)
Participant contributions	0.0	0.0
Other	13.6	(0.9)
Benefit obligations - end of year	1,021.1	905.7	973.1
Fair value of plan assets — beginning of year	687.2	749.8
Actual return on plan assets	98.1	(29.6)
Participant contributions	0.0	0.0
Employer contributions	16.4	27.6
Benefits paid	(62.2)	(60.7)
Other	9.4	0.1
Fair value of plan assets — end of year	748.9	687.2	749.8
Funded (Unfunded) Status	(272.2)	(218.5)
Assets for Plan Benefits, Defined Benefit Plan	0.0	0.0
Current liabilities	(0.5)	(0.1)
Non-current liabilities	(271.7)	(218.4)
Total amount recognized	(272.2)	(218.5)
Net actuarial loss	382.1	330.1
Prior service cost (credit)	7.3	8.5
Net amount recognized	389.4	338.6
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligations - beginning of year	241.9	265.9
Service cost (excluding expense)	1.7	2.2	1.8
Interest cost	9.5	8.3	8.3
Plan Amendments	0.0	12.8
Actuarial (gain) loss	18.9	(29.4)
Benefits paid	(25.6)	(24.4)
Participant contributions	5.8	5.6
Other	2.3	0.9
Benefit obligations - end of year	254.5	241.9	265.9
Fair value of plan assets — beginning of year	240.2	262.5
Actual return on plan assets	35.1	(8.2)
Participant contributions	0.5	0.5
Employer contributions	2.5	3.0
Benefits paid	(18.6)	(17.6)
Other	0.0	0.0
Fair value of plan assets — end of year	259.7	240.2	$ 262.5
Funded (Unfunded) Status	5.2	(1.7)
Assets for Plan Benefits, Defined Benefit Plan	48.5	32.1
Current liabilities	(3.5)	(3.5)
Non-current liabilities	(39.8)	(30.3)
Total amount recognized	5.2	(1.7)
Net actuarial loss	72.6	82.1
Prior service cost (credit)	(7.9)	(9.9)
Net amount recognized	$ 64.7	$ 72.2