XML 93 R80.htm IDEA: XBRL DOCUMENT v3.22.0.1
Capital Stock (Narrative) (Details)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2021
USD ($)
directors
$ / shares
shares
Dec. 31, 2020
$ / shares
Number of directors | directors 23  
Preferred Stock, Shares Issued 4,600,000  
Sale of Stock, Consideration Received on Transaction | $ $ 965.0  
Class A Common Stock (Shares) [Member]    
Common Stock, Par or Stated Value Per Share | $ / shares $ 0.01 $ 0.01
Class B Common Stock (Shares)    
Common Stock, Par or Stated Value Per Share | $ / shares $ 0.01 $ 0.01
Class B Common Stock, Class B1 [Member]    
Number of directors 3  
Class B Common Stock, Class B2 [Member]    
Number of directors 2  
Class B Common Stock, Class B3 [Member]    
Number of directors 1  
Class B common stock, Class B1, B2, B3 [Member]    
Number of directors 6  
Convertible Preferred Stock    
Stock Issued During Period, Shares, New Issues 4,584,000  
Sale of Stock, Consideration Received on Transaction | $ $ 1,000.0  
CME Group Omnibus Stock Plan [Member]    
Number of shares reserved for awards under the plan 40,200,000  
Director Stock Plan; Class A Shares [Member]    
Number of shares reserved for awards under the plan 625,000  
Employee Stock Purchase Plan; Class A Shares [Member]    
Number of shares reserved for awards under the plan 500,000  
Market value of the shares an Employee Stock Purchase Plan 90.00%  
Class A shares Purchased under Employee Stock Purchase Plan 390,000