Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended								12 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
Income Statement [Abstract]
Net Sales	$ 1,519.8	$ 1,581.6	$ 1,552.8	$ 1,505.9	$ 1,509.3	$ 1,531.8	$ 1,510.9	$ 1,477.4	$ 6,160.1	$ 6,029.4	$ 4,405.6
Cost of Sales									5,067.5	5,077.0	3,696.1
Selling, General and Administrative									511.9	471.8	347.5
Other Expense, Net									9.2	7.2	3.0
Business Combinations and Shutdown and Other Special Charges, Net									37.9	14.9	31.1
Income from Operations	132.1	122.9	144.4	134.2	107.6	166.6	110.1	74.2	533.6	458.5	327.9
Nonoperating Pension and Postretirement Benefit (Expense) Income									(39.5)	14.9	14.8
Interest Expense, Net									(140.6)	(123.7)	(89.7)
Loss on Modification or Extinguishment of Debt									0.0	(1.9)	0.0
Income before Income Taxes and Equity Income of Unconsolidated Entity									353.5	347.8	253.0
Income Tax (Expense) Benefit									(20.4)	(11.8)	321.7
Income before Equity Income of Unconsolidated Entity									333.1	336.0	574.7
Equity Income of Unconsolidated Entity									0.4	1.2	1.7
Net Income	$ 50.3	$ 83.5	$ 104.4	$ 95.3	$ 75.3	$ 135.4	$ 81.2	$ 45.3	$ 333.5	$ 337.2	$ 576.4