Income Taxes - Valuation Allowance for Deferred Tax Assets (Details) - Valuation allowance for deferred tax assets - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 107.3	$ 106.4	$ 140.6
Charged to tax expense	6.4	3.1	(27.6)
Charged to other accounts	2.0	(2.2)	(6.6)
Ending balance	$ 115.7	$ 107.3	$ 106.4