Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Apr. 02, 2020	Mar. 28, 2019
Operating activities
Net (loss) income	$ (163.0)	$ 163.1
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities
Depreciation expense	66.8	60.5
Amortization expense	0.5	0.0
Amortization of deferred financing fees	1.9	0.8
Accretion of customer supply agreement	1.1	1.1
Employee stock compensation expense	9.8	7.7
Loss on Derivative Instruments, Pretax	0.0	9.6
Gain from foreign currency transactions	(6.5)	(0.1)
Gain (Loss) on Disposition of Property Plant Equipment	0.2	(0.1)
Deferred taxes	(61.5)	8.1
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits	59.9	(6.4)
Grant liability amortization	(2.4)	(5.7)
Equity in net income of affiliate	1.5	0.0
Increase (Decrease) in Forward Provision	(9.0)	(11.3)
Changes in assets and liabilities
Accounts receivable, net	36.1	(68.8)
Inventory, net	(59.4)	23.5
Increase (Decrease) in Unbilled Receivables	144.5	(57.6)
Accounts payable and accrued liabilities	(278.6)	129.9
Profit sharing/deferred compensation	(66.7)	(48.0)
Advance payments	(19.8)	(2.2)
Income taxes receivable/payable	(32.8)	29.4
Increase (Decrease) in Billing in Excess of Cost of Earnings	39.1	4.9
Deferred revenue and other deferred credits	6.3	11.6
Other	2.2	(7.8)
Net cash (used in) provided by operating activities	(331.3)	242.2
Investing activities
Purchase of property, plant and equipment	(31.0)	(40.8)
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions	1.5	0.0
Payments to Acquire Businesses, Net of Cash Acquired	(118.1)	0.0
Payments for (Proceeds from) Other Investing Activities	0.3	0.1
Net cash used in investing activities	(147.3)	(40.7)
Financing activities
Proceeds from Lines of Credit	0.0	100.0
Proceeds from Issuance of Debt	0.0
Proceeds from Issuance of Senior Long-term Debt		250.0
Principal payments of debt	(7.3)	(2.6)
Repayments of Debt	(5.7)	0.0
Early Repayment of Senior Debt		(2.6)
Payment, Tax Withholding, Share-based Payment Arrangement	(13.1)	(10.0)
Proceeds from Stock Plans	1.3	0.0
Debt issuance and financing costs	4.8	0.0
Payments for Repurchase of Common Stock	0.0	(75.0)
Payments of Dividends	(12.4)	(12.7)
Proceeds from (Payments for) Other Financing Activities	10.0	0.0
Net cash (used in) provided by financing activities	(32.0)	249.7
Effect of exchange rate changes on cash and cash equivalents	(6.2)	(0.3)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(516.8)	450.9
Cash, cash equivalents, and restricted cash, beginning of period	2,367.2	794.1
Cash, cash equivalents, and restricted cash, end of period	1,833.6	1,228.4
Reconciliation of Cash, Cash Equivalents, and Restricted Cash [Abstract]
Restricted Cash, Current	0.3	0.3
Restricted Cash, Noncurrent	$ 16.5	$ 16.3