Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities:
Net income	$ 568.4	$ 549.4
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	100.9	120.0
Amortization of debt issuance cost and debt discount	1.8	1.9
Loss on settlement of contingent consideration	2.0	0.0
Unrealized gain on available-for-sale financial investments	0.0	(2.5)
Realized gain on available-for-sale financial investments	(1.3)	0.0
Provision for accounts receivable credit losses	3.1	2.8
Benefit for deferred income taxes	(24.0)	(6.9)
Stock-based compensation expense	32.1	35.1
Impairment of intangible assets	81.0	0.0
Impairment of investment	17.2	0.0
Impairment of property and equipment	0.3	0.0
(Gain) loss on disposal of property and equipment	(0.1)	0.2
Gain from Cboe Digital non-recourse notes and warrants wind down	(2.4)	0.0
Gain on sale of property held for sale	(1.0)	0.0
Gain on lease termination	(0.7)	0.0
Pyth tokens revenue	(1.0)	0.0
Equity earnings on investments	(26.3)	(33.7)
Changes in assets and liabilities:
Accounts receivable	(35.7)	6.9
Restricted cash and cash equivalents and customer bank deposits (included in margin deposits, clearing funds, and interoperability funds)	1,163.4	785.6
Income taxes receivable	27.4	(12.2)
Other current assets	6.3	(12.4)
Other assets	(15.9)	(26.8)
Accounts payable and accrued liabilities	(114.7)	(42.5)
Section 31 fees payable	(11.8)	(135.5)
Deferred revenue	(0.1)	(2.5)
Income taxes payable	(0.6)	(3.4)
Unrecognized tax benefits	43.1	37.7
Other liabilities	(0.4)	3.4
Net cash provided by operating activities	1,811.0	1,264.6
Cash flows from investing activities:
Purchases of available-for-sale financial investments	(46.3)	(69.7)
Proceeds from maturities of available-for-sale financial investments	67.9	135.7
Proceeds from sale of intangible assets	0.1	0.8
Proceeds from sale of property held for sale	3.3	0.0
Proceeds from sale of property and equipment	0.7	0.0
Proceeds from insurance	0.1	0.0
Contributions to investments	(3.7)	(55.8)
Purchases of property and equipment and leasehold improvements	(37.1)	(27.9)
Net cash used in investing activities	(15.0)	(16.9)
Cash flows used in financing activities:
Principal payments of current portion of long-term debt	0.0	(230.0)
Cash dividends on common stock	(183.0)	(165.0)
Repurchases of common stock from employee stock plans	(28.1)	(13.8)
Payments of contingent consideration related to acquisitions	(13.9)	(10.9)
Shares issued under employee stock purchase plan	11.0	(15.8)
Payments for Cboe Digital non-recourse notes and warrants wind down	(6.0)	0.0
Purchase of common stock	(204.3)	(78.1)
Net cash used in financing activities	(424.3)	(513.6)
Effect of foreign currency exchange rates on cash, cash equivalents, and restricted cash and cash equivalents	33.4	17.7
Increase in cash, cash equivalents, and restricted cash and cash equivalents	1,405.1	751.8
Beginning of period	1,397.1	979.9
End of period	2,802.2	1,731.7
Reconciliation of cash, cash equivalents, and restricted cash and cash equivalents:
Cash and cash equivalents	757.8	403.1
Restricted cash and cash equivalents (included in margin deposits, clearing funds, and interoperability funds)	2,033.5	1,308.9
Restricted cash and cash equivalents (included in cash and cash equivalents)	5.4	3.9
Customer bank deposits (included in margin deposits, clearing funds, and interoperability funds)	5.5	15.8
Total	2,802.2	1,731.7
Supplemental disclosure of cash transactions:
Cash paid for income taxes, net of refunds	271.4	203.7
Cash paid for interest	82.0	50.4
Supplemental disclosure of noncash investing activities:
Note receivable from sale of property held for sale	6.4	0.0
Additions of intangible assets	1.0	0.0
Supplemental disclosure of noncash financing activities:
Cboe Digital non-recourse notes and warrants asset	16.2	0.0
Cboe Digital non-recourse notes and warrants liability	$ (16.2)	$ 0.0