v3.25.4
Financial Assets And Financial Liabilities (Fair Value Table) (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes $ 6,097 $ 6,493
Total financial instruments owned, at fair value 4,982 1,924
Other assets 516 292
Total financial assets at fair value 11,595 8,709
Financial instruments sold, not yet purchased, at fair value 740 293
Accounts payable, accrued expenses and other liabilities 428 260
Total Financial Liabilities at Fair Value 1,168 553
US And Foreign Government Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 6,031 6,460
Municipal Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 66 33
Common Stock [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 4,780 1,763
Financial instruments sold, not yet purchased, at fair value 199 116
Options Owned [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 72 84
Financial instruments sold, not yet purchased, at fair value 498 96
U.S. And Foreign Government Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 63 54
Customer-Held Fractional Shares [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 428 260
Other Investments In Equity Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 88 32
Fractional Shares Repurchase Obligation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Accounts payable, accrued expenses and other liabilities 428 260
Mutual Funds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value   2
Precious Metals [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 50 21
Financial instruments sold, not yet purchased, at fair value 42 18
Currency Forward Contracts [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 17 0
Financial instruments sold, not yet purchased, at fair value 1 63
Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 6,031 6,460
Total financial instruments owned, at fair value 4,866 1,903
Other assets 516 292
Total financial assets at fair value 11,413 8,655
Financial instruments sold, not yet purchased, at fair value 214 212
Accounts payable, accrued expenses and other liabilities 428 260
Total Financial Liabilities at Fair Value 642 472
Level 1 [Member] | US And Foreign Government Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 6,031 6,460
Level 1 [Member] | Common Stock [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 4,780 1,763
Financial instruments sold, not yet purchased, at fair value 199 116
Level 1 [Member] | Options Owned [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 23 84
Financial instruments sold, not yet purchased, at fair value 15 96
Level 1 [Member] | U.S. And Foreign Government Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 63 54
Level 1 [Member] | Customer-Held Fractional Shares [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 428 260
Level 1 [Member] | Other Investments In Equity Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 88 32
Level 1 [Member] | Fractional Shares Repurchase Obligation [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Accounts payable, accrued expenses and other liabilities 428 260
Level 1 [Member] | Mutual Funds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value   2
Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 66 33
Total financial instruments owned, at fair value 116 21
Total financial assets at fair value 182 54
Financial instruments sold, not yet purchased, at fair value 526 81
Total Financial Liabilities at Fair Value 526 81
Level 2 [Member] | Municipal Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 66 33
Level 2 [Member] | Options Owned [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 49  
Financial instruments sold, not yet purchased, at fair value 483  
Level 2 [Member] | Precious Metals [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 50 21
Financial instruments sold, not yet purchased, at fair value 42 18
Level 2 [Member] | Currency Forward Contracts [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total financial instruments owned, at fair value 17 0
Financial instruments sold, not yet purchased, at fair value $ 1 $ 63