Fair Value Measurements - Fair Value Measurement (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Assets
Investments	$ 2,479	$ 2,901
Derivative assets, net	43	64
Assets	2,522	2,965
Liabilities
Securities sold, not yet purchased	2,679	3,473
Derivative liabilities, net	685	979
RFS obligations	374	329
Liabilities	3,738	4,781
Recurring measurement | Level 1
Assets
Investments	2,406	2,730
Assets	2,406	2,730
Liabilities
Securities sold, not yet purchased	1,998	3,288
Liabilities	1,998	3,288
Recurring measurement | Level 2
Assets
Investments	32	129
Derivative assets, net	43	64
Assets	75	193
Liabilities
Securities sold, not yet purchased	681	185
Derivative liabilities, net	685	979
RFS obligations	374	329
Liabilities	1,740	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	$ 7