EMPLOYEE BENEFIT PLANS - CHANGES IN THE FAIR VALUE OF PLAN ASSETS (Details) (Pension Benefits, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of changes in the fair value of pension plan assets
Beginning balance at January 1	$ 846.6
Net realized and unrealized losses	53.1	112.1
Ending balance at December 31	904.7	846.6
Level 3
Reconciliation of changes in the fair value of pension plan assets
Beginning balance at January 1	2.0	2.7
Net realized and unrealized losses	0.2	(0.3)
Purchases		0.3
Sales	(2.2)	(1.3)
Transfers into Level 3		0.8
Transfers out of Level 3		(0.2)
Ending balance at December 31	0	2.0
Net unrealized (gains) losses related to assets still held at the end of the period	0	(0.3)
Foreign government debt
Reconciliation of changes in the fair value of pension plan assets
Ending balance at December 31	12.1	10.4
Foreign government debt | Level 3
Reconciliation of changes in the fair value of pension plan assets
Beginning balance at January 1	1.3	2.2
Net realized and unrealized losses	0.1	(0.1)
Purchases		0.3
Sales	(1.4)	(1.1)
Transfers into Level 3		0
Transfers out of Level 3		0
Ending balance at December 31	0	1.3
Net unrealized (gains) losses related to assets still held at the end of the period	0	(0.1)
Corporate debt
Reconciliation of changes in the fair value of pension plan assets
Ending balance at December 31	250.5	135.5
Corporate debt | Level 3
Reconciliation of changes in the fair value of pension plan assets
Beginning balance at January 1	0.7	0.5
Net realized and unrealized losses	0.1	(0.2)
Purchases		0
Sales	(0.8)	(0.2)
Transfers into Level 3		0.8
Transfers out of Level 3		(0.2)
Ending balance at December 31	0	0.7
Net unrealized (gains) losses related to assets still held at the end of the period	$ 0	$ (0.2)