CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended								12 Months Ended			110 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Income Statement [Abstract]
Sales	$ 1,387.1	$ 1,576.6	$ 1,592.9	$ 1,553.4	$ 1,635.0	$ 1,872.4	$ 1,728.4	$ 1,710.3	$ 6,110.0	$ 6,946.1	$ 6,268.4
Operating expenses:
Cost of goods sold	1,270.6	1,357.6	1,463.7	1,347.3	1,391.0	1,441.7	1,460.7	1,528.7	5,439.2	5,822.1	5,554.9
Selling and administration									416.9	430.6	369.8
Restructuring charges									76.5	21.9	37.6	$ 285.6
Acquisition-related costs									0.0	1.0	12.8
Other operating income									0.4	6.4	3.3
Operating income									177.8	676.9	296.6
Earnings (losses) of non-consolidated affiliates									0.0	(19.7)	1.8
Interest expense									243.2	243.2	217.4
Interest income									1.0	1.6	1.8
Non-operating pension income									16.3	21.7	34.4
Other income									11.2	0.0	0.0
Income (loss) before taxes									(36.9)	437.3	117.2
Income tax (benefit) provision									(25.6)	109.4	(432.3)
Net (loss) income	$ (77.2)	$ 44.2	$ (20.0)	$ 41.7	$ 53.3	$ 195.1	$ 58.6	$ 20.9	$ (11.3)	$ 327.9	$ 549.5
Net (loss) income per common share:
Basic	$ (0.49)	$ 0.27	$ (0.12)	$ 0.25	$ 0.32	$ 1.17	$ 0.35	$ 0.13	$ (0.07)	$ 1.97	$ 3.31
Diluted	$ (0.49)	$ 0.27	$ (0.12)	$ 0.25	$ 0.32	$ 1.16	$ 0.35	$ 0.12	$ (0.07)	$ 1.95	$ 3.26
Average common shares outstanding:
Basic									162.3	166.8	166.2
Diluted									162.3	168.4	168.5