INCOME TAXES - Schedule of (Benefit from) Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal
Current									$ 0.0	$ 0.0	$ (0.3)
Deferred									31.2	33.4	(17.9)
Total federal tax expense (benefit)									31.2	33.4	(18.2)
State
Current									0.3	0.0	0.1
Deferred									(4.6)	10.6	(3.1)
Total state tax expense (benefit)									(4.3)	10.6	(3.0)
Foreign
Current									14.4	18.4	8.4
Deferred									0.1	(4.4)	(3.5)
Total foreign tax expense (benefit)									14.5	14.0	4.9
Provision for (benefit from) income taxes	$ 6.3	$ 10.2	$ 20.9	$ 4.0	$ 24.3	$ 6.9	$ 29.4	$ (2.6)	$ 41.4	$ 58.0	$ (16.3)