REVENUES - Revenue Disaggregated By Revenue Source (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Interest expenses related to credit facilities	$ (6)	$ (6)	$ (17)	$ (18)
Total net interest revenues	251	128	693	257
Total net revenues	467	361	1,394	978
Options
Disaggregation of Revenue [Line Items]
Total transaction-based revenues	124	124	384	364
Cryptocurrencies
Disaggregation of Revenue [Line Items]
Total transaction-based revenues	23	51	92	163
Equities
Disaggregation of Revenue [Line Items]
Total transaction-based revenues	27	31	79	96
Other
Disaggregation of Revenue [Line Items]
Total transaction-based revenues	11	2	30	5
Transaction-based revenues
Disaggregation of Revenue [Line Items]
Total transaction-based revenues	185	208	585	628
Other revenues
Disaggregation of Revenue [Line Items]
Total transaction-based revenues	31	25	116	93
Interest on corporate cash and investments
Disaggregation of Revenue [Line Items]
Net interest revenues	75	29	217	40
Margin interest
Disaggregation of Revenue [Line Items]
Net interest revenues	67	48	177	122
Interest on segregated cash and cash equivalents and deposits
Disaggregation of Revenue [Line Items]
Net interest revenues	59	20	156	27
Cash sweep
Disaggregation of Revenue [Line Items]
Net interest revenues	35	8	86	10
Securities lending, net
Disaggregation of Revenue [Line Items]
Net interest revenues	17	29	70	76
Credit card, net
Disaggregation of Revenue [Line Items]
Net interest revenues	$ 4	$ 0	$ 4	$ 0