Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Cash flows from operating activities:
Net income	$ 485.7	$ 349.9
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	60.2	69.1
Amortization of debt issuance cost and debt discount	1.2	1.2
Loss on settlement of contingent consideration	0.0	3.0
Provision for accounts receivable credit losses	2.2	1.6
Benefit for deferred income taxes	(19.1)	(21.2)
Stock-based compensation expense	25.7	22.0
Impairment of intangible assets	17.1	81.0
Impairment of minority investment	0.0	16.0
Gain from Cboe Digital non-recourse notes and warrants wind down	0.0	(2.4)
Equity loss (earnings) on investments	6.6	(26.5)
Other (gain) loss adjustments, net	(4.4)	(2.5)
Changes in assets and liabilities:
Accounts receivable	28.1	(44.2)
Restricted cash and cash equivalents and customer bank deposits (included in margin deposits, clearing funds, and interoperability funds)	555.6	1,923.2
Income taxes receivable	33.3	39.6
Other assets	16.2	(7.7)
Accounts payable and accrued liabilities	(55.9)	(113.3)
Section 31 fees payable	56.4	68.7
Deferred revenue	4.1	4.0
Income taxes payable	(1.0)	(1.0)
Unrecognized tax benefits	37.9	27.1
Other liabilities	(3.3)	1.9
Net cash provided by operating activities	1,246.6	2,389.5
Cash flows from investing activities:
Purchases of available-for-sale financial investments	(174.8)	(46.3)
Proceeds from maturities of available-for-sale financial investments	70.3	20.6
Gain from investments	4.6	0.0
Proceeds from sale of intangible assets	0.8	0.0
Proceeds from sale of property held for sale	0.0	3.3
Proceeds from sale of property and equipment	0.0	0.7
Proceeds from insurance	0.0	0.1
Contributions to investments	(2.5)	(3.7)
Purchases of property and equipment and leasehold improvements, net	(35.0)	(25.1)
Net cash used in investing activities	(136.6)	(50.4)
Cash flows used in financing activities:
Cash dividends on common stock	(132.8)	(116.7)
Repurchases of common stock from employee stock plans	(23.6)	(27.2)
Payments of contingent consideration related to acquisitions	0.0	(13.0)
Shares issued under employee stock purchase plan	4.8	(5.4)
Payments for Cboe Digital non-recourse notes and warrants wind down	0.0	(6.0)
Purchase of common stock, including commissions and excise taxes	(66.7)	(177.9)
Net cash used in financing activities	(218.3)	(346.2)
Effect of foreign currency exchange rates on cash, cash equivalents, and restricted cash and cash equivalents	299.4	(41.4)
Increase in cash, cash equivalents, and restricted cash and cash equivalents	1,191.1	1,951.5
Beginning of period	1,765.8	1,397.1
End of period	2,956.9	3,348.6
Reconciliation of cash, cash equivalents, and restricted cash and cash equivalents:
Cash and cash equivalents	1,256.3	614.6
Restricted cash and cash equivalents (included in margin deposits, clearing funds, and interoperability funds)	1,668.5	2,723.8
Restricted cash and cash equivalents (included in other current assets)	30.2	5.2
Customer bank deposits (included in margin deposits, clearing funds, and interoperability funds)	1.9	5.0
Total	2,956.9	3,348.6
Supplemental disclosure of cash transactions:
Cash paid for income taxes, net of refunds	148.6	178.3
Cash paid for interest	46.6	62.4
Supplemental disclosure of noncash investing activities:
Note receivable from sale of property held for sale	0.0	6.4
Additions of intangible assets	0.0	1.0
Supplemental disclosure of noncash financing activities:
Unsettled purchases of common stock	0.0	(1.8)
Excise tax on purchases of common stock	0.2	0.0
Cboe Digital non-recourse notes and warrants asset	0.0	16.2
Cboe Digital non-recourse notes and warrants liability	$ 0.0	$ (16.2)