STOCKHOLDERS' EQUITY - Components of Accumulated Other Comprehensive Income, Net of Tax (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ (24.2)	$ 24.9
Other comprehensive income (loss) before reclassifications	(84.0)	(15.1)
Amounts reclassified from accumulated other comprehensive income (loss)	(2.5)	1.6
Net current-period other comprehensive income (loss)	(86.5)	(13.5)
Ending balance	(110.7)	11.4
Gains (Losses) on Hedge Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	4.5	(2.9)
Other comprehensive income (loss) before reclassifications	3.7	4.6
Amounts reclassified from accumulated other comprehensive income (loss)	(2.7)	1.5
Net current-period other comprehensive income (loss)	1.0	6.1
Ending balance	5.5	3.2
Unrealized Gains (Losses) on Available-for-Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(16.0)	29.5
Other comprehensive income (loss) before reclassifications	(90.8)	(10.0)
Amounts reclassified from accumulated other comprehensive income (loss)	0.1	0.0
Net current-period other comprehensive income (loss)	(90.7)	(10.0)
Ending balance	(106.7)	19.5
Foreign Currency Translation Gains (Losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(7.9)	4.7
Other comprehensive income (loss) before reclassifications	3.1	(9.7)
Amounts reclassified from accumulated other comprehensive income (loss)	0.0	0.0
Net current-period other comprehensive income (loss)	3.1	(9.7)
Ending balance	(4.8)	(5.0)
Employee Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(4.8)	(6.4)
Other comprehensive income (loss) before reclassifications	0.0	0.0
Amounts reclassified from accumulated other comprehensive income (loss)	0.1	0.1
Net current-period other comprehensive income (loss)	0.1	0.1
Ending balance	$ (4.7)	$ (6.3)

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

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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Amount before tax and reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount before tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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