Consolidated Statements of Cash Flows $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Operating activities
Net (loss) income	$ (870.3)	$ 530.1	$ 617.0
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities
Depreciation and amortization expense	277.6	251.7	231.0
Amortization of deferred financing fees	20.4	3.5	17.9
Accretion of customer supply agreement	2.0	4.3	4.1
Employee stock compensation expense	24.2	36.1	27.4
Loss (gain) from derivative instruments	0.0	8.1	(7.2)
Loss (gain) from foreign currency transactions	25.0	1.6	(0.3)
Loss on disposition of assets	26.4	4.9	1.8
Deferred taxes	94.0	86.1	(38.0)
Long term income tax payable	1.5
Pension and other post-retirement benefits, net	44.5	(20.0)	(33.4)
Grant liability amortization	(3.5)	(16.2)	(21.6)
Equity in net loss (income) of affiliates	4.6	0.2	(0.6)
Increase (Decrease) in Forward Position	216.5	40.7	(170.9)
Changes in assets and liabilities
Accounts receivable, net	168.3	12.8	(47.9)
Inventory, net	(39.5)	(95.4)	(61.3)
Increase (Decrease) in Contract with Customer, Asset	168.2	(5.2)	(8.5)
Accounts payable and accrued liabilities	(592.7)	34.6	244.5
Profit sharing/deferred compensation	(28.2)	16.0	(40.9)
Advance payments	(21.0)	120.8	(98.3)
Income taxes receivable/payable	(246.3)	(59.6)	(28.4)
Increase (Decrease) in Contract with Customer, Liability	(49.5)	(13.0)	208.3
Deferred revenue and other deferred credits	9.2	6.2	16.9
Other	23.7	(25.6)	(41.7)
Net cash provided (used in) by operating activities	(744.9)	922.7	769.9
Investing activities
Purchase of property, plant and equipment	(118.9)	(232.2)	(271.2)
Payments to Acquire Businesses, Net of Cash Acquired	(388.5)
Payments to Acquire Interest in Subsidiaries and Affiliates	0.0	(7.9)
Other Investing Activities	(5.4)	7.7	(3.4)
Payments for (Proceeds from) Other Investing Activities	(5.4)	(0.2)	(3.4)
Net cash used in investing activities	(502.0)	(239.9)	(267.8)
Proceeds from Issuance of Secured Debt	400.0
Financing activities
Proceeds from Issuance of Senior Long-term Debt	1,700.0	250.0	1,300.0
Proceeds from revolving credit facility	0.0	900.0	0.0
Payments on revolving credit facility	(800.0)	(100.0)	0.0
Principal payments of debt	(31.6)	(13.4)	(6.7)
Repayments of Debt	(439.7)	(16.6)	(256.3)
Early Repayment of Senior Debt	0.0	0.0	(300.0)
Payment, Tax Withholding, Share-based Payment Arrangement	(14.5)	(12.9)	(15.6)
Proceeds from Stock Plans	2.6	2.6	2.1
Debt issuance and financing costs	(41.9)	0.0	(23.2)
Payments for Repurchase of Common Stock	(0.1)	(75.8)	(805.8)
Payments of Dividends	(15.4)	(50.4)	(48.0)
Proceeds from (Payments for) Other Financing Activities	(0.1)	0.9
Net cash provided by (used in) financing activities	769.5	884.4	(153.5)
Effect of exchange rate changes on cash and cash equivalents	3.3	5.9	0.0
Net (decrease) increase in cash, cash equivalents, and restricted cash for the period	(474.1)	1,573.1	348.6
Cash, cash equivalents, and restricted cash, end of period	1,873.3	2,350.5	773.6
Restricted Cash, Current	0.3	0.3	0.3
Restricted Cash and Investments, Noncurrent	19.5	16.4	20.2
Supplemental information
Interest paid	146.6	93.2	70.4
Proceeds from Income Tax Refunds	(62.5)
Income taxes paid		105.0	202.3
Property acquired through capital leases	26.3	120.3	26.8
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	1,893.1	$ 2,367.2	$ 794.1
Proceeds from (Repayments of) Other Debt	$ 10.0