PENSIONS AND POSTRETIREMENT BENEFITS (Effect of Fair Value Measurements Using Significant Unobservable Inputs (Level 3) on Changes in Pension Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	$ 215.6	$ 202.4
Actual return on plan assets:
Relating to assets still held at the reporting date	12.5	16.1
Purchases	5.2	57.9
Sales	8.2	65.6
Fair value of plan assets — end of year	229.1	215.6
Hedge Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	37.4	40.6
Actual return on plan assets:
Relating to assets still held at the reporting date	(0.2)	2.5
Purchases	0.0	39.0
Sales	0.0	45.1
Fair value of plan assets — end of year	37.2	37.4
Private Equity Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	39.8	36.1
Actual return on plan assets:
Relating to assets still held at the reporting date	1.4	0.3
Purchases	5.2	4.5
Sales	7.8	5.6
Fair value of plan assets — end of year	42.6	39.8
Structured Finance [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	72.9	63.8
Actual return on plan assets:
Relating to assets still held at the reporting date	5.9	9.1
Purchases	0.0	0.0
Sales	0.0	0.0
Fair value of plan assets — end of year	78.8	72.9
Real Estate [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Roll Forward]
Fair value of plan assets — beginning of year	65.5	61.9
Actual return on plan assets:
Relating to assets still held at the reporting date	5.4	4.2
Purchases	0.0	14.4
Sales	0.4	14.9
Fair value of plan assets — end of year	$ 70.5	$ 65.5