Condensed Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues:
Total revenues	$ 985.8	$ 800.8	$ 1,960.3	$ 1,811.6
Cost of revenues:
Total cost of revenues	561.7	450.2	1,118.1	1,095.5
Revenues less cost of revenues	424.1	350.6	842.2	716.1
Operating expenses:
Compensation and benefits	86.2	67.7	167.4	140.0
Depreciation and amortization	40.2	40.6	81.1	82.6
Technology support services	18.1	16.2	37.3	33.4
Professional fees and outside services	24.1	22.4	43.8	38.0
Travel and promotional expenses	5.5	1.9	8.4	3.5
Facilities costs	6.6	5.4	13.1	10.7
Acquisition-related costs	14.3	1.8	16.3	5.2
Goodwill impairment charge	460.1		460.1
Other expenses	6.4	4.6	12.4	8.1
Total operating expenses	661.5	160.6	839.9	321.5
Operating (loss) income	(237.4)	190.0	2.3	394.6
Non-operating (expenses) income:
Interest expense, net	(14.6)	(12.3)	(25.4)	(24.6)
Other (expense) income, net	(4.8)	1.5	(8.8)	2.1
(Loss) income before income tax provision	(256.8)	179.2	(31.9)	372.1
Income tax (benefit) provision	(72.3)	73.7	43.0	129.4
Net (loss) income	(184.5)	105.5	(74.9)	242.7
Net income allocated to participating securities		(0.3)		(0.7)
Net (loss) income allocated to common stockholders	$ (184.5)	$ 105.2	$ (74.9)	$ 242.0
Basic (loss) earnings per share (in dollars per share)	$ (1.74)	$ 0.99	$ (0.70)	$ 2.26
Diluted (loss) earnings per share (in dollars per share)	$ (1.74)	$ 0.98	$ (0.70)	$ 2.26
Basic weighted average shares outstanding (in shares)	106.3	106.8	106.5	107.1
Diluted weighted average shares outstanding (in shares)	106.3	106.9	106.5	107.3
Cash and spot markets
Revenues:
Total revenues	$ 458.5	$ 372.7	$ 920.4	$ 921.6
Data and access solutions
Revenues:
Total revenues	123.9	103.0	242.8	203.6
Derivatives markets
Revenues:
Total revenues	403.4	325.1	797.1	686.4
Liquidity payments
Cost of revenues:
Total cost of revenues	429.0	377.9	896.5	879.7
Routing and clearing
Cost of revenues:
Total cost of revenues	20.9	19.9	43.2	47.0
Section 31 fees
Cost of revenues:
Total cost of revenues	79.6	28.8	115.3	120.7
Royalty fees and other cost of revenues
Cost of revenues:
Total cost of revenues	$ 32.2	$ 23.6	$ 63.1	$ 48.1