Income Taxes - Schedule of Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Currently payable
U.K.	$ 0.5	$ (3.5)	$ 2.0
International	0.4	2.7	5.4
Total current taxes	0.9	(0.8)	7.4
Deferred
U.K.	1.3	7.1	(1.1)
International	(9.3)	2.7	(0.9)
Total deferred taxes	(8.0)	9.8	(2.0)
Total provision for income taxes	$ (7.1)	$ 9.0	$ 5.4

Amount of current federal tax expense (benefit) attributable to income (loss) from continuing operations. Includes, but is not limited to, current national tax expense (benefit) for non-US (United States of America) jurisdiction.

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