REVENUE - REVENUE DISAGGREGATED BY REVENUE SOURCE (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Margin interest	$ 35	$ 28
Securities lending	24	35
Interest on segregated cash and securities	1	1
Other interest revenue	1	1
Interest expenses related to credit facilities	(6)	(3)
Net interest revenues	55	62
Total net revenues	299	522
Options
Disaggregation of Revenue [Line Items]
Revenues	127	198
Cryptocurrencies
Disaggregation of Revenue [Line Items]
Revenues	54	88
Equities
Disaggregation of Revenue [Line Items]
Revenues	36	133
Other
Disaggregation of Revenue [Line Items]
Revenues	1	1
Transaction-based revenues
Disaggregation of Revenue [Line Items]
Revenues	218	420
Other revenues
Disaggregation of Revenue [Line Items]
Revenues	$ 26	$ 40