Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Reserves for discontinued operations, environmental and restructuring	$ 188.3	$ 148.7
Accrued pension and other postretirement benefits	2.4	2.1
Capital loss, foreign tax and other credit carryforwards	7.5	6.0
Net operating loss carryforwards	227.0	219.3
Deferred expenditures capitalized for tax	18.7	15.2
Other	163.6	143.3
Deferred tax assets	607.5	534.6
Valuation allowance, net	(303.3)	(261.4)
Deferred tax assets, net of valuation allowance	304.2	273.2
Intangibles and property, plant and equipment, net	380.0	331.2
Deferred tax liabilities	380.0	331.2
Net deferred tax assets (liabilities)	$ (75.8)	$ (58.0)