REGULATORY CAPITAL - Subsidiaries with Regulatory Capital Requirements (Details) $ in Millions	Mar. 31, 2026 USD ($)
Cboe Trading
Regulatory Capital Requirement [Line Items]
Actual	$ 16.9
Minimum Requirement	0.9
BIDS Trading
Regulatory Capital Requirement [Line Items]
Actual	12.0
Minimum Requirement	0.2
Cboe Fixed Income
Regulatory Capital Requirement [Line Items]
Actual	7.1
Minimum Requirement	0.1
Cboe Europe
Regulatory Capital Requirement [Line Items]
Actual	68.3
Minimum Requirement	35.9
Cboe Chi-X Europe
Regulatory Capital Requirement [Line Items]
Actual	0.3
Minimum Requirement	0.1
Cboe NL
Regulatory Capital Requirement [Line Items]
Actual	16.4
Minimum Requirement	8.1
Cboe Clear Europe
Regulatory Capital Requirement [Line Items]
Actual	136.8
Minimum Requirement	81.4
CFE
Regulatory Capital Requirement [Line Items]
Actual	131.7
Minimum Requirement	41.2
Cboe SEF
Regulatory Capital Requirement [Line Items]
Actual	14.8
Minimum Requirement	2.5
Cboe Digital Exchange
Regulatory Capital Requirement [Line Items]
Actual	19.0
Minimum Requirement	0.0
Cboe Clear U.S.
Regulatory Capital Requirement [Line Items]
Actual	29.8
Minimum Requirement	15.0
Cboe Australia
Regulatory Capital Requirement [Line Items]
Actual	17.4
Minimum Requirement	$ 6.0