Discontinued Operations (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Income tax (benefit) expense	$ (3.0)	$ 0.0	$ (3.0)	$ 1.7
Loss from disposal of discontinued business, before income tax			0.0	(0.4)
Valuation Loss On Pension Liabilities				11.8
EMEA and Pacific Rim Business [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Income tax (benefit) expense	(2.0)		(2.0)	1.7
Loss from disposal of discontinued business, before income tax	0.0			$ (0.4)
Armstrong Flooring Inc [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Income tax (benefit) expense	$ (1.0)		$ (1.0)