v3.26.1
Intangible Assets And Goodwill (Components Of Intangible Assets) (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Intangible Assets [Line Items]    
Intangible assets—other, net $ 2,550.8 $ 2,610.7
Intangible assets—other, net 2,550.8 2,610.7
Intangible assets—trading products [1] 17,175.3 17,175.3
Trade Names [Member]    
Intangible Assets [Line Items]    
Total intangible assets - other, net 450.0 450.0
Clearing Firm, Market Data And Other Customer Relationships [Member]    
Intangible Assets [Line Items]    
Assigned Value 4,696.0 4,703.0
Accumulated amortization (2,608.2) (2,557.5)
Intangible assets—other, net 2,087.8 2,145.5
Technology-Related Intellectual Property [Member]    
Intangible Assets [Line Items]    
Assigned Value 62.5 62.5
Accumulated amortization (62.5) (62.5)
Intangible assets—other, net 0.0 0.0
Other [Member]    
Intangible Assets [Line Items]    
Assigned Value 73.1 73.9
Accumulated amortization (60.1) (58.7)
Intangible assets—other, net 13.0 15.2
Total Amortizable Intangible Assets [Member]    
Intangible Assets [Line Items]    
Assigned Value 4,831.6 4,839.4
Accumulated amortization (2,730.8) (2,678.7)
Intangible assets—other, net $ 2,100.8 $ 2,160.7
[1] Trading products represent futures and options products acquired in our business combinations with CBOT Holdings, Inc., NYMEX Holdings, Inc. and The Board of Trade of Kansas City, Missouri, Inc. Clearing and transaction fees are generated through the trading of these products. These trading products, most of which have traded for decades, require authorization from the Commodity Futures Trading Commission (CFTC). Product authorizations from the CFTC have no term limits.