Acquisitions and Divestitures - Divestitures (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Sep. 09, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense		$ (49.7)	$ (35.4)	$ (129.2)	$ (96.0)
Disposed of by Sale | Knight LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of businesses, net of cash remitted	$ 49.4
Gain on sale	$ 34.8
Income tax expense		$ (5.5)		$ (5.5)