Rendering

Component: (Network and Table)
Network
2412404 - Disclosure - Employee Benefit Plans (Change in Plan Assets) (Details)
(http://www.cmegroup.com/role/EmployeeBenefitPlansChangeInPlanAssetsDetails)
TableStatement [Table]
Slicers (applies to each fact value in each table cell)
Reporting Entity [Axis]0001156375 (http://www.sec.gov/CIK)
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Axis]Pension Plans [Member]
Statement [Line Items]Period [Axis]
2016-01-01 - 2016-12-31
2015-01-01 - 2015-12-31
2014-01-01 - 2014-12-31
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
 
 
 
Balance at January 1
217,500,000  
225,100,000  
193,600,000  
Actual return on plan assets
16,000,000  
(7,200,000) 
14,300,000  
Employer contributions
15,000,000  
22,600,000  
26,000,000  
Benefits paid
(9,700,000) 
(23,000,000) 
(8,800,000) 
Balance at December 31
238,800,000  
 
217,500,000  
 
225,100,000