Income Taxes - Valuation Allowances (Details) - 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 of year	$ 77.3	$ 141.5	$ 128.1
Expiring tax credits	(0.1)	(0.2)	(0.7)
Acquisitions and dispositions	(0.9)	0.0	(0.8)
Changes in judgment about deferred tax assets(a)	32.5	(46.1)	8.8
Income from continuing operations	86.0	173.5	103.1
Other comprehensive income (loss)	42.2	201.0	89.5
Foreign currency exchange effects	1.0	(2.6)	(1.1)
End of year	128.0	77.3	141.5
Valuation Allowance of Deferred Tax Assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Income from continuing operations	11.3	(1.4)	7.4
Other comprehensive income (loss)	$ 6.9	$ (13.9)	$ (0.2)