INCOME TAXES - Reconciliation of Beginning and Ending Amount of Uncertain Tax Positions (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
Uncertain gross tax positions, beginning balance	$ 150.7	$ 225.6	$ 245.5
Current year tax positions	55.4	37.8	77.7
Increase in prior year tax positions	0.8	13.9	63.7
Decrease in prior year tax positions	(3.8)	(78.8)	(65.0)
Settlements	0.0	(46.5)	(95.3)
Lapse of statutes of limitations	0.0	(1.3)	(1.0)
Uncertain gross tax positions, ending balance	$ 203.1	$ 150.7	$ 225.6

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.

+ References

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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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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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