INCOME TAXES - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Tax
Beginning Balance	$ 66.3	$ 64.9
Increase based on tax positions taken in a prior year	3.5	0.3
Decrease based on tax positions taken in a prior year	(3.3)	(2.2)
Increase based on tax positions taken in the current year	5.5	7.1
Decrease resulting from the lapse of statutes of limitations	(3.2)	(3.8)
Ending Balance	68.8	66.3
Interest and Penalties
Beginning Balance	11.7	9.8
Increase based on tax positions taken in a prior year	6.4	3.4
Decrease based on tax positions taken in a prior year	(1.0)	(0.3)
Increase based on tax positions taken in the current year	0.0	0.0
Decrease resulting from the lapse of statutes of limitations	(1.5)	(1.2)
Ending Balance	15.6	11.7
Total
Beginning balance	78.0	74.7
Increase based on tax positions taken in a prior year	9.9	3.7
Decrease based on tax positions taken in a prior year	(4.3)	(2.5)
Increase based on tax positions taken in the current year	5.5	7.1
Decrease resulting from the lapse of statutes of limitations	(4.7)	(5.0)
Ending balance	$ 84.4	$ 78.0