FAIR VALUE MEASUREMENT - Fair value hierarchy of financial instruments held (Details) - USD ($) $ in Millions	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Assets:
Investments fair value	$ 64.2		$ 9.1
Deferred compensation plan assets	27.5		28.0
Digital assets - safeguarded assets	22.9	$ 22.4
Digital assets held	0.9
Total assets	115.5		37.1
Liabilities:
Contingent consideration liabilities	39.1		70.5
Deferred compensation plan liabilities	27.5		28.0
Digital assets - safeguarded liabilities	22.9	$ 22.4
Cboe Digital restricted common units liability	15.5
Cboe Digital warrant liability	5.9
Debt	1,573.9		1,333.6
Total liabilities	1,684.8		1,432.1
Level 1
Assets:
Investments fair value	64.2		9.1
Deferred compensation plan assets	27.5		28.0
Digital assets - safeguarded assets	22.9
Digital assets held	0.9
Total assets	115.5		37.1
Liabilities:
Deferred compensation plan liabilities	27.5		28.0
Digital assets - safeguarded liabilities	22.9
Total liabilities	50.4		28.0
Level 2
Liabilities:
Debt	1,573.9		1,333.6
Total liabilities	1,573.9		1,333.6
Level 3
Liabilities:
Contingent consideration liabilities	39.1		70.5
Cboe Digital restricted common units liability	15.5
Cboe Digital warrant liability	5.9
Total liabilities	$ 60.5		$ 70.5