GOODWILL, INTANGIBLE ASSETS, NET, AND DIGITAL ASSETS HELD - Intangible assets by segment (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Intangible Assets
Balance at beginning of the period		$ 1,561.5	$ 1,662.8
Dispositions			(0.8)
Amortization		(88.7)	(116.6)	$ (124.3)
Changes in foreign currency exchange rates		(16.0)	16.1
Additions		1.2
Sales		0.1
Impairment of intangible assets		(81.0)	0.0	0.0
Balance at end of the period		1,376.9	1,561.5	1,662.8
Options
Intangible Assets
Balance at beginning of the period		134.1	146.1
Dispositions			0.0
Amortization		(7.7)	(12.0)
Changes in foreign currency exchange rates		0.0	0.0
Additions		0.0
Sales		0.0
Impairment of intangible assets		0.0
Balance at end of the period		126.4	134.1	146.1
North American Equities
Intangible Assets
Balance at beginning of the period		935.3	992.8
Dispositions			0.0
Amortization		(50.6)	(59.5)
Changes in foreign currency exchange rates		(6.3)	2.0
Additions		1.2
Sales		0.0
Impairment of intangible assets		0.0
Balance at end of the period		879.6	935.3	992.8
Europe and Asia Pacific
Intangible Assets
Balance at beginning of the period		352.5	359.9
Dispositions			0.0
Amortization		(16.1)	(21.5)
Changes in foreign currency exchange rates		(9.7)	14.1
Additions		0.0
Sales		0.0
Impairment of intangible assets		0.0
Balance at end of the period		326.7	352.5	359.9
Global FX
Intangible Assets
Balance at beginning of the period		56.2	72.8
Dispositions			0.0
Amortization		(12.0)	(16.6)
Changes in foreign currency exchange rates		0.0	0.0
Additions		0.0
Sales		0.0
Impairment of intangible assets		0.0
Balance at end of the period		44.2	56.2	72.8
Digital
Intangible Assets
Balance at beginning of the period		83.4	91.2
Dispositions			(0.8)
Amortization		(2.3)	(7.0)
Changes in foreign currency exchange rates		0.0	0.0
Additions		0.0
Sales		0.1
Impairment of intangible assets	$ (81.0)	(81.0)
Balance at end of the period		$ 0.0	$ 83.4	$ 91.2