Components of Accumulated Other Comprehensive Loss - Reclassifications out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of goods sold	$ (840.7)	$ (507.1)	$ (1,501.1)	$ (971.8)
Selling, general and administrative expenses	(5.8)	(8.7)	(17.5)	(24.8)
Other operating expense - net	(0.2)	(0.1)	(0.4)	(0.2)
Income tax effect	(42.3)	48.3	(44.0)	50.6
Net income (loss)	37.4	(35.1)	55.1	(175.1)
Reclassification out of accumulated other comprehensive income [Member] | Defined benefit plan liabilities
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of goods sold	0.5	0.7	0.9	1.4
Selling, general and administrative expenses	0.2	0.2	0.3	0.4
Other operating expense - net	0.3	0.4	0.5	0.8
Income tax effect	(0.1)	(0.1)	(0.2)	(0.2)
Net income (loss)	0.9	1.2	1.5	2.4
Reclassification out of accumulated other comprehensive income [Member] | Unrealized loss on financial instruments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of goods sold	(0.1)	(0.1)	(0.1)	(0.1)
Income tax effect	0.0	0.0	0.0	0.0
Net income (loss)	$ (0.1)	$ (0.1)	$ (0.1)	$ (0.1)