BUSINESS COMBINATIONS - Schedule of Acquisition Date Fair Value of Consideration Transferred (Details) - USD ($) $ in Millions	Sep. 30, 2025	Jun. 02, 2025	Feb. 26, 2025	Dec. 31, 2024
Business Combination [Line Items]
Goodwill	$ 386			$ 179
TradePMR
Business Combination [Line Items]
Cash and cash equivalents			$ 25
Receivables from brokers, dealers, and clearing organizations			5
Prepaid expenses			1
Other current assets			9
Other non-current assets			3
Goodwill			112
Intangible assets			81
Accounts payable and accrued expenses			(1)
Other current liabilities			(19)
Other non-current liabilities			(41)
Net assets acquired			$ 175
Bitstamp
Business Combination [Line Items]
Cash and cash equivalents		$ 65
Cash and securities segregated under federal and other regulations		1,103
Receivable from users, net		13
Prepaid expenses		6
Other current assets		15
Other non-current assets		8
Goodwill		93
Intangible assets		70
Accounts payable and accrued expenses		(28)
Payable to users		(1,115)
Other current liabilities		(4)
Other non-current liabilities		(2)
Net assets acquired		$ 224