ACCUMULATED OTHER COMPREHENSIVE LOSS - ROLLFORWARD (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Changes in accumulated other comprehensive loss, net of tax
Accumulated other comprehensive loss, balance at beginning of period	$ (23.2)	$ (40.9)
Other comprehensive income (loss) before reclassifications	(6.0)	13.9
Amounts reclassified out of accumulated other comprehensive loss	1.6	3.8
Other comprehensive income (loss), net of tax	(4.4)	17.7	1.6
Accumulated other comprehensive loss, balance at end of period	(27.6)	(23.2)	(40.9)
Cash flow hedges
Changes in accumulated other comprehensive loss, net of tax
Accumulated other comprehensive loss, balance at beginning of period	(3.1)	(5.2)
Other comprehensive income (loss) before reclassifications	0	0.7
Amounts reclassified out of accumulated other comprehensive loss	(0.1)	1.4
Other comprehensive income (loss), net of tax	(0.1)	2.1
Accumulated other comprehensive loss, balance at end of period	(3.2)	(3.1)
Defined benefit plans
Changes in accumulated other comprehensive loss, net of tax
Accumulated other comprehensive loss, balance at beginning of period	(20.1)	(35.7)
Other comprehensive income (loss) before reclassifications	(6.0)	13.2
Amounts reclassified out of accumulated other comprehensive loss	1.7	2.4
Other comprehensive income (loss), net of tax	(4.3)	15.6
Accumulated other comprehensive loss, balance at end of period	$ (24.4)	$ (20.1)