STOCKHOLDERS' EQUITY - Components of Accumulated Other Comprehensive Income, Net of Tax (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ (79.8)	$ (144.2)	$ (162.5)	$ (24.2)
Other comprehensive income (loss) before reclassifications	21.0	(51.5)	106.0	(182.3)
Amounts reclassified from accumulated other comprehensive income (loss)	2.3	8.1	0.0	18.9
Net current-period other comprehensive income (loss)	23.3	(43.4)	106.0	(163.4)
Ending balance	(56.5)	(187.6)	(56.5)	(187.6)
Gains (Losses) on Hedge Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	5.6	9.9	(2.9)	4.5
Other comprehensive income (loss) before reclassifications	2.0	(5.7)	12.6	(11.0)
Amounts reclassified from accumulated other comprehensive income (loss)	2.3	8.0	0.2	18.7
Net current-period other comprehensive income (loss)	4.3	2.3	12.8	7.7
Ending balance	9.9	12.2	9.9	12.2
Unrealized Gains (Losses) on Available-for-Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(103.5)	(140.1)	(154.2)	(16.0)
Other comprehensive income (loss) before reclassifications	25.6	(37.3)	76.5	(161.4)
Amounts reclassified from accumulated other comprehensive income (loss)	0.0	0.0	(0.2)	0.0
Net current-period other comprehensive income (loss)	25.6	(37.3)	76.3	(161.4)
Ending balance	(77.9)	(177.4)	(77.9)	(177.4)
Foreign Currency Translation Gains (Losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	16.9	(9.3)	(6.6)	(7.9)
Other comprehensive income (loss) before reclassifications	(6.6)	(8.5)	16.9	(9.9)
Amounts reclassified from accumulated other comprehensive income (loss)	0.0	0.0	0.0	0.0
Net current-period other comprehensive income (loss)	(6.6)	(8.5)	16.9	(9.9)
Ending balance	10.3	(17.8)	10.3	(17.8)
Employee Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	1.2	(4.7)	1.2	(4.8)
Other comprehensive income (loss) before reclassifications	0.0	0.0	0.0	0.0
Amounts reclassified from accumulated other comprehensive income (loss)	0.0	0.1	0.0	0.2
Net current-period other comprehensive income (loss)	0.0	0.1	0.0	0.2
Ending balance	$ 1.2	$ (4.6)	$ 1.2	$ (4.6)

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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- Definition

Amount, after tax, of accumulated increase (decrease) in equity from transaction and other event and circumstance from nonowner source.

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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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