Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization expense	$ 315.6	$ 337.1	$ 327.6
Amortization of deferred financing fees	12.6	11.9	15.1
Accretion of customer supply agreement	2.6	2.2	3.5
Employee stock compensation expense	29.2	36.6	25.8
(Gain) loss from derivative instruments	(0.5)	17.1	(0.1)
Loss (gain) from foreign currency transactions	7.5	(18.9)	(4.4)
Gains (Losses) on Extinguishment of Debt	11.8	2.6	0.0
Payment for Debt Extinguishment or Debt Prepayment Cost	(11.8)	(2.6)	0.0
Loss on disposition of assets	6.9	1.1	4.1
Deferred taxes	18.1	8.5	(4.5)
Pension and other post-retirement plans expense (income)	55.1	37.1	(109.1)
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits	186.6	19.5	(173.8)
Grant liability amortization	(1.1)	(1.5)	(1.5)
Equity in net loss of affiliates	0.3	1.6	2.8
Increase (Decrease) in Forward Position	(194.9)	(89.7)	(10.4)
Changes in assets and liabilities
Accounts receivable, net	(96.6)	(39.4)	51.5
Inventory, net	(295.1)	(118.2)	30.9
Increase (Decrease) in Contract with Customer, Asset	(18.0)	(63.9)	(70.9)
Accounts payable and accrued liabilities	213.8	220.7	160.2
Profit sharing/deferred compensation	(25.0)	(22.5)	6.2
Advance payments	114.1	(133.2)	2.7
Income taxes receivable/payable	(3.4)	9.5	302.4
Increase (Decrease) in Contract with Customer, Liability	(3.0)	(30.4)	(82.4)
Other	4.3	0.1	(12.3)
Net cash used in operating activities	(225.8)	(394.6)	(63.2)
Investing activities
Purchase of property, plant and equipment	(148.0)	(121.6)	(150.6)
Payments to Acquire Businesses, Net of Cash Acquired	0.0	(31.3)	(21.1)
Payments for (Proceeds from) Other Investing Activities	(0.2)	2.6	(7.9)
Net cash used in investing activities	(147.8)	(155.5)	(163.8)
Financing activities
Proceeds from Issuance of Senior Long-term Debt	1,200.0	900.0	0.0
Proceeds from revolving credit facility	5.4	0.0	0.0
Payments on revolving credit facility	(0.6)	0.0	0.0
Principal payments of debt	(64.1)	(47.6)	(42.1)
Repayments of Debt	(5.9)	(6.0)	(401.5)
Early Repayment of Senior Debt	(1,200.0)	(779.2)	(300.0)
Payment, Tax Withholding, Share-based Payment Arrangement	(6.6)	(7.2)	(5.2)
Proceeds from Stock Plans	6.3	3.9	3.0
Debt issuance and financing costs	(28.5)	(32.3)	(3.4)
Proceeds from Other Debt	(180.0)
Payments of Dividends	0.0	(4.2)	(4.3)
Proceeds from Noncontrolling Interests	0.0	3.7	0.0
Net cash (used in) provided by financing activities	531.6	(261.0)	(163.5)
Proceeds from Issuance of Secured Debt	242.7	0.0	600.0
Net decrease in cash, cash equivalents, and restricted cash for the period	167.5	(820.0)	(394.7)
Cash, cash equivalents, and restricted cash, end of period	823.5	658.6	1,478.6
Restricted Cash, Current	0.1	0.2	0.3
Restricted Cash and Investments, Noncurrent	22.3	19.6	19.5
Supplemental information
Interest paid	285.3	222.5	198.4
Proceeds from Income Tax Refunds	(2.8)
Income taxes paid		(15.2)	(314.4)
Property acquired through capital leases	31.7	49.6	32.1
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	845.9	678.4	1,498.4
Proceeds from (Repayments of) Other Debt	180.0	0.0	(10.0)
Gain (Loss) on Contract Termination	(1.8)	(21.9)	0.0
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations	9.5	(8.9)	(4.2)
Interest paid	285.3	222.5	198.4
Proceeds from Income Tax Refunds	2.8
Income taxes paid		15.2	314.4
Lease Obligation Incurred	31.7	49.6	32.1
Payments to Acquire Businesses, Net of Cash Acquired	0.0	31.3	21.1
Payments of Dividends	0.0	4.2	4.3
Proceeds from Noncontrolling Interests	0.0	3.7	0.0
Proceeds from (Payments for) Other Financing Activities	0.0	(289.5)	0.0
Payment, Tax Withholding, Share-based Payment Arrangement	6.6	7.2	5.2
Proceeds from Stock Plans	6.3	3.9	3.0
Gains (Losses) on Extinguishment of Debt	(11.8)	(2.6)	0.0
Payment for Debt Extinguishment or Debt Prepayment Cost	11.8	2.6	0.0
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	(2.4)	0.0	0.0
Increase (Decrease) in Other Operating Assets and Liabilities, Net	(4.3)	(0.1)	12.3
Increase (Decrease) in Deferred Liabilities	53.6	(14.4)	14.2
Proceeds from Issuance of Common Stock	220.7	0.0	0.0
Proceeds from Other Debt	(180.0)
Proceeds from (Repayments of) Other Debt	180.0	0.0	(10.0)
Repayments of Long-term Debt	64.1	47.6	42.1
Repayments of Debt	5.9	6.0	401.5
Repayments of Lines of Credit	0.6	0.0	0.0
Early Repayment of Senior Debt	1,200.0	779.2	300.0
Asset Acquisition, Consideration Transferred, Contingent Consideration	(6.0)	0.0	0.0
Payments of Financing Costs	28.5	32.3	3.4
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations	9.5	(8.9)	(4.2)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (616.1)	$ (546.2)	$ (540.8)