REVENUES - Schedule of Revenue Disaggregated by Revenue Source (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Interest expenses related to credit facilities	$ (8)	$ (6)	$ (22)	$ (18)
Total net interest revenues	456	274	1,103	813
Total net revenues	1,274	637	3,190	1,937
Transaction-based revenues
Disaggregation of Revenue [Line Items]
Total transaction-based revenues and other revenues	730	319	1,852	975
Options
Disaggregation of Revenue [Line Items]
Total transaction-based revenues and other revenues	304	202	809	538
Cryptocurrencies
Disaggregation of Revenue [Line Items]
Total transaction-based revenues and other revenues	268	61	680	268
Equities
Disaggregation of Revenue [Line Items]
Total transaction-based revenues and other revenues	86	37	208	116
Other
Disaggregation of Revenue [Line Items]
Total transaction-based revenues and other revenues	72	19	155	53
Margin interest
Disaggregation of Revenue [Line Items]
Net interest revenues	153	83	377	228
Interest on segregated cash, cash equivalents, securities, and deposits
Disaggregation of Revenue [Line Items]
Net interest revenues	103	61	236	187
Cash Sweep
Disaggregation of Revenue [Line Items]
Net interest revenues	64	46	172	129
Securities lending, net
Disaggregation of Revenue [Line Items]
Net interest revenues	87	19	164	68
Interest on corporate cash and investments
Disaggregation of Revenue [Line Items]
Net interest revenues	39	67	134	203
Credit card, net
Disaggregation of Revenue [Line Items]
Net interest revenues	17	4	40	16
Other revenues
Disaggregation of Revenue [Line Items]
Total transaction-based revenues and other revenues	88	44	235	149
Robinhood Gold subscription revenues
Disaggregation of Revenue [Line Items]
Total transaction-based revenues and other revenues	47	28	129	77
Proxy revenues
Disaggregation of Revenue [Line Items]
Total transaction-based revenues and other revenues	7	8	52	53
Other
Disaggregation of Revenue [Line Items]
Total transaction-based revenues and other revenues	34	8	54	19
Net interest revenues	$ 1	$ 0	$ 2	$ 0