v3.26.1
Equity And Earnings Per Share (IBG LLC Ownership of Member Interests) (Details)
Mar. 31, 2026
shares
Ownership Percentage 100.00%
Membership Interests 1,696,353,742
IBG Inc [Member]  
Ownership Percentage 26.30%
Membership Interests 445,616,326
Holdings [Member]  
Ownership Percentage 73.70%
Membership Interests 1,250,737,416