ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) Accumulated Other Comprehensive Income (Loss) and Related Tax Effects (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss), Before Taxes	$ (162.4)	$ (144.7)	$ (141.8)
Accumulated Other Comprehensive Income (Loss), Tax	123.4	123.4	123.8
Accumulated other comprehensive loss	(39.0)	(21.3)	(18.0)	$ (245.8)
Postretirement Benefit Liability [Member]
Accumulated Other Comprehensive Income (Loss), Before Taxes	(387.3)	(384.0)	(364.8)
Accumulated Other Comprehensive Income (Loss), Tax	123.4	123.4	123.4
Accumulated other comprehensive loss	(263.9)	(260.6)	(241.4)
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss), Before Taxes	225.4	239.3	220.7
Accumulated Other Comprehensive Income (Loss), Tax	0.0	0.0	0.0
Accumulated other comprehensive loss	225.4	$ 239.3	220.7
Unrealized Gain Loss On Derivatives [Member]
Accumulated Other Comprehensive Income (Loss), Before Taxes	(0.5)		2.2
Accumulated Other Comprehensive Income (Loss), Tax	0.0		0.4
Accumulated other comprehensive loss	$ (0.5)		2.6
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Before Taxes			0.1
Accumulated Other Comprehensive Income (Loss), Tax			0.0
Accumulated other comprehensive loss			$ 0.1