Income Taxes, Benefit from (provision for) income taxes (Details) - USD ($) $ in Millions			3 Months Ended		4 Months Ended	6 Months Ended
		Mar. 05, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Components of Benefit From (Provision For) Income Taxes:
Texas Margin Tax	[1]		$ (24.1)	$ (7.0)		$ (27.4)	$ (14.7)
Other			(0.1)	(2.2)		(0.5)	(2.5)
Benefit from (provision for) income taxes			(31.2)	(59.7)		(41.2)	119.5
OTA Holdings, Inc. [Member]
Components of Benefit From (Provision For) Income Taxes:
Benefit from (provision for) income taxes		$ 72.2	$ (7.0)	$ (50.5)	$ 64.5	$ (13.3)	$ 136.7

[1] Although the Texas Margin Tax is not considered a state income tax, it has the characteristics of an income tax since it is determined by applying a tax rate to a base that considers our Texas-sourced revenues and expenses.