GOODWILL, INTANGIBLE ASSETS, NET, AND DIGITAL ASSETS HELD - Intangible Assets by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Intangible Assets
Balance at beginning of the period			$ 1,297.2
Amortization	$ (14.6)	$ (17.2)	(31.3)	$ (35.6)
Reclassified to assets held for sale			(75.1)
Changes in foreign currency exchange rates			(6.4)
Remeasurement to fair value	(0.4)		(0.4)		$ (18.9)
Balance at end of the period	1,184.0		1,184.0		1,297.2
Options
Intangible Assets
Balance at beginning of the period			119.9
Amortization			(2.9)
Reclassified to assets held for sale			0.0
Changes in foreign currency exchange rates			0.0
Remeasurement to fair value			0.0
Balance at end of the period	117.0		117.0		119.9
North American Equities
Intangible Assets
Balance at beginning of the period			824.6
Amortization			(17.7)
Reclassified to assets held for sale			(44.7)
Changes in foreign currency exchange rates			(1.6)
Remeasurement to fair value			(0.4)
Balance at end of the period	760.2		760.2		824.6
Europe and Asia Pacific
Intangible Assets
Balance at beginning of the period			318.1
Amortization			(6.5)
Reclassified to assets held for sale			(30.4)
Changes in foreign currency exchange rates			(4.8)
Remeasurement to fair value			0.0
Balance at end of the period	276.4		276.4		318.1
Global FX
Intangible Assets
Balance at beginning of the period			34.6
Amortization			(4.2)
Reclassified to assets held for sale			0.0
Changes in foreign currency exchange rates			0.0
Remeasurement to fair value			0.0
Balance at end of the period	$ 30.4		$ 30.4		$ 34.6