Fair Value Measurements - Fair Value Measurement (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Assets
Derivative assets, net	$ 24	$ 64
Liabilities
Securities sold, not yet purchased	3,644	3,473
Derivative liabilities, net	702	979
Recurring measurement
Assets
Investments	3,206	2,901
Derivative assets, net	24	64
Assets	3,230	2,965
Liabilities
Securities sold, not yet purchased	3,644	3,473
Derivative liabilities, net	702	979
RFS obligations	294	329
Liabilities	4,640	4,781
Recurring measurement | Level 1
Assets
Investments	3,105	2,730
Assets	3,105	2,730
Liabilities
Securities sold, not yet purchased	3,469	3,288
Liabilities	3,469	3,288
Recurring measurement | Level 2
Assets
Investments	60	129
Derivative assets, net	24	64
Assets	84	193
Liabilities
Securities sold, not yet purchased	175	185
Derivative liabilities, net	702	979
RFS obligations	294	329
Liabilities	1,171	1,493
Recurring measurement | Level 3
Assets
Investments	41	42
Assets	41	$ 42
Fair value, nonrecurring | Level 3
Liabilities
Estimated fair value	46
Fair value of related party note receivable	$ 11