DEBT - Schedule of long-term debt (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023	Mar. 16, 2022	Dec. 15, 2020	Jan. 12, 2017
Debt Instrument
Total debt	$ 1,440.6	$ 1,439.2
Line of Credit | Revolving Credit Agreement
Debt Instrument
Total debt	0.0	0.0
Line of Credit | Cboe Clear Europe Credit Facility
Debt Instrument
Total debt	0.0	0.0
3.650% Senior Notes
Debt Instrument
Debt instrument face amount	$ 650.0	$ 650.0			$ 650.0
Interest rate (as a percent)	3.65%	3.65%			3.65%
3.650% Senior Notes | Senior Notes
Debt Instrument
Total debt	$ 648.5	$ 647.9
1.625% Senior Notes
Debt Instrument
Debt instrument face amount	$ 500.0	$ 500.0		$ 500.0
Interest rate (as a percent)	1.625%	1.625%		1.625%
1.625% Senior Notes | Senior Notes
Debt Instrument
Total debt	$ 495.3	$ 494.8
3.000% Senior Notes
Debt Instrument
Debt instrument face amount	$ 300.0	$ 300.0	$ 300.0
Interest rate (as a percent)	3.00%	3.00%	3.00%
3.000% Senior Notes | Senior Notes
Debt Instrument
Total debt	$ 296.8	$ 296.5