INCOME TAXES (U.S. Tax Reform) (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2018
INCOME TAXES
Tax expenses change in statutory tax rate, U.S. only	$ (15.2)	$ 0.2	$ 1.4	$ (13.6)
Tax expenses changes to indefinite reinvestment assertion	(6.7)	(0.4)	7.9	0.8
Tax expenses Repatriation Tax (settled with NOL, non-cash)	(2.0)	4.8	34.8	37.6
Tax expenses Net discrete impacts of the enactment of U.S. Tax Reform	$ (23.9)	$ 4.6	$ 44.1	24.8
Deferred tax liability change in statutory tax rate, U.S. only				(3.4)
Deferred tax liability changes to indefinite reinvestment assertion				0.8
Deferred tax liability Repatriation Tax (settled with NOL, non-cash)				37.6
Deferred tax liability Net discrete impacts of the enactment of U.S. Tax Reform				35.0
Current tax receivable change in statutory tax rate, U.S. only				10.2
Current tax receivable Net discrete impacts of the enactment of U.S. Tax Reform				$ 10.2