CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Sales	$ 5,758.0	$ 6,110.0	$ 6,946.1
Operating expenses:
Cost of goods sold	5,374.6	5,439.2	5,822.1
Selling and administration	422.0	416.9	430.6
Restructuring charges	9.0	76.5	21.9
Acquisition-related costs	0.0	0.0	1.0
Goodwill impairment	699.8	0.0	0.0
Other operating income	0.7	0.4	6.4
Operating (loss) income	(746.7)	177.8	676.9
Losses of non-consolidated affiliates	0.0	0.0	(19.7)
Interest expense	292.7	243.2	243.2
Interest income	0.5	1.0	1.6
Non-operating pension income	18.9	16.3	21.7
Other income	0.0	11.2	0.0
Income (loss) before taxes	(1,020.0)	(36.9)	437.3
Income tax (benefit) provision	(50.1)	(25.6)	109.4
Net (loss) income	$ (969.9)	$ (11.3)	$ 327.9
Net (loss) income per common share:
Basic	$ (6.14)	$ (0.07)	$ 1.97
Diluted	$ (6.14)	$ (0.07)	$ 1.95
Average common shares outstanding:
Basic	157.9	162.3	166.8
Diluted	157.9	162.3	168.4