LONG-TERM DEBT AND OTHER FINANCING ARRANGEMENTS Guarantee Fees (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Nov. 01, 2017	Dec. 31, 2016
Line of Credit Facility [Line Items]
Interest Expense, Debt		$ 20,484	$ 26,901	$ 42,805	$ 59,553
CME NV and CME BV [Member]
Line of Credit Facility [Line Items]
Outstanding Shares Pledged, Percentage		100.00%		100.00%
2018 Euro Term Loan [Member]
Line of Credit Facility [Line Items]
Percentage of Debt Hedged by Interest Rate Derivatives	[1]	0.21%		0.21%
Debt Instrument, Guarantee Fee, Stated Percentage		5.54%		5.54%
Debt Instrument, Interest Rate, All-In Rate	[1]	7.25%		7.25%
Debt Instrument, Interest Rate, Stated Percentage		1.50%		1.50%
2019 Euro Term Loan [Member]
Line of Credit Facility [Line Items]
Percentage of Debt Hedged by Interest Rate Derivatives		0.31%		0.31%
Debt Instrument, Guarantee Fee, Stated Percentage		5.44%		5.44%
Debt Instrument, Interest Rate, All-In Rate		7.25%		7.25%
Debt Instrument, Interest Rate, Stated Percentage		1.50%		1.50%
2021 Euro Term Loan [Member]
Line of Credit Facility [Line Items]
Percentage of Debt Hedged by Interest Rate Derivatives		0.28%		0.28%
Debt Instrument, Guarantee Fee, Stated Percentage		5.47%		5.47%
Debt Instrument, Interest Rate, All-In Rate		7.25%		7.25%
Debt Instrument, Interest Rate, Stated Percentage		1.50%		1.50%
Guarantee Fee [Member]
Line of Credit Facility [Line Items]
Interest Expense, Debt		$ 14,600	$ 19,800	$ 31,000	$ 28,900
2021 Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, All-In Rate	[2],[3]	9.30%		9.30%
Debt Instrument, Interest Rate, Stated Percentage	[2],[3]	9.30%		9.30%
2021 Revolving Credit Facility [Member] | CME NV and CME BV [Member]
Line of Credit Facility [Line Items]
Outstanding Shares Pledged, Percentage							100.00%
Scenario, Forecast [Member] | 2018 Euro Term Loan [Member]
Line of Credit Facility [Line Items]
Percentage of Debt Hedged by Interest Rate Derivatives						0.14%
Minimum [Member] | 2021 Euro Term Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, All-In Rate		5.00%		5.00%
Minimum [Member] | 2021 Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		7.00%		7.00%
Minimum Required Cash Portion [Member] | 2021 Euro Term Loan [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, All-In Rate		5.00%		5.00%
Minimum Required Cash Portion [Member] | 2021 Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		5.00%		5.00%

[1] (1) Effective until November 1, 2017. From November 1, 2017 through maturity on November 1, 2018, the rate fixed pursuant to interest rate hedges will decrease to 0.14%, with a corresponding increase in the Guarantee Fee rate, such that the all-in borrowing rate remains 7.25% if our net leverage ratio remains unchanged.

[2] (2) As at June 30, 2017, the 2021 Revolving Credit Facility was undrawn.

[3] (3) Based on the three month LIBOR of 1.30% as at June 30, 2017.