CLEARING OPERATIONS - Valuation (Details) $ / shares in Units, $ in Millions	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($) unit $ / shares
Digital Assets - Safeguarded Assets and Safeguarded Liabilities
Fair Value	$ 0.0	$ 51.3
Bitcoin ("BTC")
Digital Assets - Safeguarded Assets and Safeguarded Liabilities
Number of Units | unit		821
Valuation per unit (in dollars per share) | $ / shares		$ 42,492
Fair Value		$ 34.9
Ethereum ("ETH")
Digital Assets - Safeguarded Assets and Safeguarded Liabilities
Number of Units | unit		6,270
Valuation per unit (in dollars per share) | $ / shares		$ 2,282
Fair Value		$ 14.3
Litecoin ("LTC")
Digital Assets - Safeguarded Assets and Safeguarded Liabilities
Number of Units | unit		16,329
Valuation per unit (in dollars per share) | $ / shares		$ 74
Fair Value		$ 1.2
Bitcoin Cash ("BCH")
Digital Assets - Safeguarded Assets and Safeguarded Liabilities
Number of Units | unit		1,374
Valuation per unit (in dollars per share) | $ / shares		$ 261
Fair Value		$ 0.4
USD Coin ("USDC")
Digital Assets - Safeguarded Assets and Safeguarded Liabilities
Number of Units | unit		506,652
Valuation per unit (in dollars per share) | $ / shares		$ 1
Fair Value		$ 0.5