v3.26.1
Revenue From Contracts With Customers (Disaggregation of Revenue ) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Disaggregation of Revenue [Line Items]    
Revenue from Contract with Customer, Excluding Assessed Tax [1] $ 699 $ 592
United States [Member]    
Disaggregation of Revenue [Line Items]    
Revenue from Contract with Customer, Excluding Assessed Tax [1] 413 362
International [Member]    
Disaggregation of Revenue [Line Items]    
Revenue from Contract with Customer, Excluding Assessed Tax [1] 286 230
Commissions [Member]    
Disaggregation of Revenue [Line Items]    
Revenue from Contract with Customer, Excluding Assessed Tax 613 514
Market Data Fees [Member]    
Disaggregation of Revenue [Line Items]    
Revenue from Contract with Customer, Excluding Assessed Tax [2] 21 19
Risk Exposure Fees [Member]    
Disaggregation of Revenue [Line Items]    
Revenue from Contract with Customer, Excluding Assessed Tax [2] 26 28
Payments For Order Flow [Member]    
Disaggregation of Revenue [Line Items]    
Revenue from Contract with Customer, Excluding Assessed Tax [2] 15 13
FDIC Sweep Fees [Member]    
Disaggregation of Revenue [Line Items]    
Revenue from Contract with Customer, Excluding Assessed Tax [2] 10 8
Others [Member]    
Disaggregation of Revenue [Line Items]    
Revenue from Contract with Customer, Excluding Assessed Tax [2] $ 14 $ 10
[1] Based on the location of the subsidiaries in which the revenues are recorded.
[2] in “Other fees and services” in the condensed consolidated statements of comprehensive income.