INCOME TAXES - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns
Unrecognized tax benefits at January 1	$ 4.6	$ 6.2	$ 43.0
Additions for tax positions related to current year	0.5	0.5	6.8
Additions for tax positions related to prior year	7.4	0.0	0.0
Reductions - current year decrease	0.0	0.0	(5.4)
Reductions - prior year decrease	(1.2)	0.0	(38.2)
Lapse of statute of limitations	0.0	(2.1)	0.0
Unrecognized tax benefits at December 31	$ 11.3	$ 4.6	$ 6.2

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of unrecognized tax benefits.

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Amount of decrease in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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