Collateralized Transactions - Securities Segregated for Regulatory Purposes (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Collateralized Agreements [Abstract]
Segregated securities	$ 28,116	$ 22,256

Securities deposited in a special reserve account for the exclusive benefit of customers pursuant to SEC Regulations.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Rule 15c3-3
-Number 240
-Section 15c3-3
-Paragraph e
-Subparagraph (1)
-Publisher SEC

Name:	us-gaap_SecuritiesReserveDepositRequiredAndMade
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant