v3.26.1
Financial Assets And Financial Liabilities (Fair Value Table) (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes $ 7,503 $ 6,097
Financial instruments owned, at fair value 3,452 4,982
Other assets 499 516
Total financial assets at fair value 11,454 11,595
Financial instruments sold, but not yet purchased, at fair value 514 740
Accounts payable, accrued expenses and other liabilities 450 428
Total Financial Liabilities at Fair Value 964 1,168
Municipal Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 65 66
Financial instruments owned, at fair value 14  
Common Stock [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned, at fair value 3,167 4,780
Financial instruments sold, but not yet purchased, at fair value 280 199
Options Owned [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned, at fair value 129 72
Financial instruments sold, but not yet purchased, at fair value 171 498
U.S. And Foreign Government Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 7,438 6,031
Financial instruments owned, at fair value 71 63
Customer-Held Fractional Shares [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 450 428
Other Investments In Equity Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 49 88
Precious Metals [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned, at fair value 56 50
Financial instruments sold, but not yet purchased, at fair value 51 42
Currency Forward Contracts [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned, at fair value 15 17
Financial instruments sold, but not yet purchased, at fair value 12 1
Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 7,438 6,031
Financial instruments owned, at fair value 3,315 4,866
Other assets 499 516
Total financial assets at fair value 11,252 11,413
Financial instruments sold, but not yet purchased, at fair value 322 214
Accounts payable, accrued expenses and other liabilities 450 428
Total Financial Liabilities at Fair Value 772 642
Level 1 [Member] | Common Stock [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned, at fair value 3,167 4,780
Financial instruments sold, but not yet purchased, at fair value 280 199
Level 1 [Member] | Options Owned [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned, at fair value 77 23
Financial instruments sold, but not yet purchased, at fair value 42 15
Level 1 [Member] | U.S. And Foreign Government Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 7,438 6,031
Financial instruments owned, at fair value 71 63
Level 1 [Member] | Customer-Held Fractional Shares [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 450 428
Level 1 [Member] | Other Investments In Equity Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 49 88
Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 65 66
Financial instruments owned, at fair value 137 116
Total financial assets at fair value 202 182
Financial instruments sold, but not yet purchased, at fair value 192 526
Total Financial Liabilities at Fair Value 192 526
Level 2 [Member] | Municipal Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities segregated for regulatory purposes 65 66
Financial instruments owned, at fair value 14  
Level 2 [Member] | Options Owned [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned, at fair value 52 49
Financial instruments sold, but not yet purchased, at fair value 129 483
Level 2 [Member] | Precious Metals [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned, at fair value 56 50
Financial instruments sold, but not yet purchased, at fair value 51 42
Level 2 [Member] | Currency Forward Contracts [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned, at fair value 15 17
Financial instruments sold, but not yet purchased, at fair value $ 12 $ 1