ACCUMULATED OTHER COMPREHENSIVE LOSS Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
AOCI - Postretirement Benefits	$ (129.7)	$ (131.5)	$ (132.4)	$ 128.2	$ 130.5	$ 131.0	$ (129.7)	$ 128.2	$ (133.3)	$ (131.6)
AOCI - Cumulative Translation Adjustment	(277.7)	(301.2)	(303.3)	(275.4)	(241.0)	(246.3)	(277.7)	(275.4)	(252.0)	(243.9)
Net change during period - AOCI Postretirement Benefits	1.8	0.9	0.9	2.3	0.5	0.6	3.6	3.4
Net change during period - AOCI Cumulative Translation Adjustment	23.5	2.1	(51.3)	(34.4)	5.3	(2.4)
Total other comprehensive loss, net of tax	25.3	3.0	(50.4)	(32.1)	5.8	(1.8)	(22.1)	(28.1)
Total accumulated other comprehensive loss	$ (407.4)	$ (432.7)	$ (435.7)	$ (403.6)	$ (371.5)	$ (377.3)	$ (407.4)	$ (403.6)	$ (385.3)	$ (375.5)