DEBT - Schedule of long-term debt (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Mar. 16, 2022	Dec. 15, 2020	Jan. 12, 2017
Debt Instrument
Total debt	$ 1,442.9	$ 1,441.0
Revolving Credit Agreement | Line of Credit
Debt Instrument
Total debt	0.0	0.0
Cboe Clear Europe Credit Facility | Line of Credit
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%		3.65%
3.650% Senior Notes | Senior Notes
Debt Instrument
Total debt	$ 649.3	$ 648.6
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%
1.625% Senior Notes | Senior Notes
Debt Instrument
Total debt	$ 496.3	$ 495.5
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	$ 297.3	$ 296.9