Condensed Consolidating Financial Information (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 02, 2020	Mar. 28, 2019	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 1,077.3	$ 1,967.8
Operating costs and expenses
Cost of sales	1,112.5	1,658.3
Selling, general and administrative	77.4	63.6
Restructuring Charges	42.6	0.0
Research and development	12.3	12.9
Total operating costs and expenses	1,244.8	1,734.8
Operating income	(167.5)	233.0
Interest expense and financing fee amortization	(32.2)	(18.8)
Other expense, net	(49.0)	(11.0)
Income (loss) before income taxes and equity in net loss of affiliates and subsidiaries	(248.7)	203.2
Income tax benefit (provision)	87.2	(40.1)
Income (loss) Before Equity In Net Income (Loss) Of Affiliates and Subsidiaries	(161.5)	163.1
Equity in net loss of affiliate	(1.5)	0.0
Equity in net income of subsidiaries	0.0	0.0
Net (loss) income	(163.0)	163.1
Total other comprehensive income (loss)	(141.7)	10.0
Comprehensive Income, Net of Tax, Attributable to Parent	(304.7)	173.1
Assets
Cash and cash equivalents	1,850.4	1,245.0	$ 2,367.2	$ 794.1
Restricted Cash and Cash Equivalents	0.3		0.3
Accounts receivable, net	508.6		546.4
Unbilled Receivables, Current	380.9		528.3
Inventory	1,168.7		1,118.8
Other current assets	134.0		98.7
Total current assets	4,026.1		4,643.0
Property, plant and equipment, net	2,253.2		2,271.7
Operating Lease, Right-of-Use Asset	47.5		48.9
Unbilled Receivable, Non Current	10.4		6.4
Pension assets	282.6		449.1
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	192.6		106.5
Goodwill	78.5		2.4
Intangible Assets, Net (Excluding Goodwill)	30.6		1.2
Deferred income taxes	79.6		76.8
Other assets	7,001.1		7,606.0
Total assets
Liabilities	740.7		1,058.3
Accounts payable	286.1		240.2
Accrued expenses	17.6		84.5
Profit sharing	52.7		50.2
Operating Lease, Liability, Current	5.9		6.0
Operating lease liabilities, short-term	17.8		21.6
Billings in Excess of Cost, Noncurrent	388.9		356.3
Billings in Excess of Cost, Current	166.9		158.3
Provision for Loss on Contracts	91.5		83.9
Forward loss provision, short-term	17.9		14.8
Deferred grant income liability — current	37.0		42.9
Other current liabilities	1,434.1		1,760.7
Long-term debt	2,978.2		2,984.1
Operating Lease, Liability, Noncurrent	41.7		43.0
Advance payments, long-term	327.3		333.3
Pension/OPEB obligation	50.9		35.7
Provision for Loss on Contacts, Non Current	146.9		163.5
Deferred grant income liability — non-current	27.4		29.0
Deferred revenue and other deferred credits	36.8		34.4
Deferred Tax Liabilities, Net, Noncurrent	8.2		8.3
Deferred income taxes	104.3		95.8
Total equity	1,456.4		1,761.9
Total liabilities and equity	7,001.1		7,606.0
Operating activities
Net cash (used in) operating activities	(331.3)	242.2
Investing activities
Purchase of property, plant and equipment	(31.0)	(40.8)
Payments for (Proceeds from) Other Investing Activities	0.3	0.1
Payments to Acquire Businesses, Net of Cash Acquired	(118.1)	0.0
Payments for (Proceeds from) Other Investing Activities	(1.8)
Net cash used in investing activities	(147.3)	(40.7)
Proceeds from Issuance of Debt	0.0
Proceeds from Lines of Credit	0.0	100.0
Proceeds from (Payments for) Other Financing Activities	10.0	0.0
Proceeds from Issuance of Senior Long-term Debt		(250.0)
Financing activities
Principal payments of debt	(7.3)	(2.6)
Repayments of Debt	(5.7)	0.0
Early Repayment of Senior Debt		(2.6)
Collection on (repayment of) intercompany debt		0.0
Payment, Tax Withholding, Share-based Payment Arrangement	(13.1)	(10.0)
Proceeds (payments) from subsidiary for purchase of treasury stock		0.0
Debt issuance and financing costs	4.8	0.0
Payments for Repurchase of Common Stock	0.0	(75.0)
Proceeds from subsidiary (payments to Parent) to pay dividends	0.0	0.0
Payments of Dividends	(12.4)	(12.7)
Proceeds from Stock Plans	1.3	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 and cash equivalents, beginning of period	2,350.5	773.6
Cash, cash equivalents, and restricted cash, end of period	1,833.6	1,228.4
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	(164.0)	(170.6)
Operating costs and expenses
Cost of sales	(164.0)	(170.6)
Restructuring Charges	0.0
Total operating costs and expenses	(164.0)	(170.6)
Interest expense and financing fee amortization	0.8	1.0
Other expense, net	(0.8)	(1.0)
Equity in net income of subsidiaries	139.5	(194.7)
Net (loss) income	139.5	(194.7)
Total other comprehensive income (loss)	117.2	(20.4)
Comprehensive Income, Net of Tax, Attributable to Parent	256.7	(215.1)
Assets
Restricted Cash and Cash Equivalents	0.0		0.0
Accounts receivable, net	(325.3)		(320.2)
Unbilled Receivables, Current	0.0		0.0
Inventory			0.0
Total current assets	(325.3)		(320.2)
Operating Lease, Right-of-Use Asset	0.0		0.0
Unbilled Receivable, Non Current	0.0		0.0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent			0.0
Goodwill	0.0		0.0
Intangible Assets, Net (Excluding Goodwill)	0.0		0.0
Investment in subsidiary	(2,277.4)		(2,600.3)
Deferred income taxes	(186.8)		(186.8)
Other assets	(2,789.5)		(3,107.3)
Total assets
Liabilities	(325.3)		(320.2)
Operating Lease, Liability, Current	0.0		0.0
Billings in Excess of Cost, Noncurrent	0.0		0.0
Billings in Excess of Cost, Current	0.0		0.0
Provision for Loss on Contracts	0.0		0.0
Other current liabilities	(325.3)		(320.2)
Long-term debt	(86.2)		(86.2)
Operating Lease, Liability, Noncurrent	0.0		0.0
Provision for Loss on Contacts, Non Current	0.0		0.0
Deferred Tax Liabilities, Net, Noncurrent	0.0		0.0
Deferred income taxes	(100.6)		(100.6)
Total equity	(2,277.4)		(2,600.3)
Total liabilities and equity	(2,789.5)		(3,107.3)
Operating activities
Net cash (used in) operating activities
Investing activities
Payments for (Proceeds from) Other Investing Activities		0.0
Payments to Acquire Businesses, Net of Cash Acquired	0.0
Payments for (Proceeds from) Other Investing Activities	0.0
Proceeds from Lines of Credit		0.0
Proceeds from (Payments for) Other Financing Activities	0.0
Financing activities
Early Repayment of Senior Debt		0.0
Collection on (repayment of) intercompany debt		0.0
Payment, Tax Withholding, Share-based Payment Arrangement	0.0	0.0
Proceeds (payments) from subsidiary for purchase of treasury stock		0.0
Debt issuance and financing costs	0.0
Payments for Repurchase of Common Stock		0.0
Proceeds from subsidiary (payments to Parent) to pay dividends	0.0	0.0
Payments of Dividends	0.0	0.0
Proceeds from Stock Plans	0.0
Effect of exchange rate changes on cash and cash equivalents
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	0.0	0.0
Operating costs and expenses
Selling, general and administrative	3.5	2.3
Restructuring Charges	0.0
Total operating costs and expenses	3.5	2.3
Operating income	(3.5)	(2.3)
Income (loss) before income taxes and equity in net loss of affiliates and subsidiaries	(3.5)	(2.3)
Income tax benefit (provision)	1.2	0.5
Income (loss) Before Equity In Net Income (Loss) Of Affiliates and Subsidiaries	(2.3)	(1.8)
Equity in net income of subsidiaries	(160.7)	164.9
Net (loss) income	(163.0)	163.1
Total other comprehensive income (loss)	(141.7)	10.0
Comprehensive Income, Net of Tax, Attributable to Parent	(304.7)	173.1
Assets
Restricted Cash and Cash Equivalents	0.0		0.0
Unbilled Receivables, Current	0.0		0.0
Inventory			0.0
Operating Lease, Right-of-Use Asset	0.0		0.0
Unbilled Receivable, Non Current	0.0		0.0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent			0.0
Goodwill	0.0		0.0
Intangible Assets, Net (Excluding Goodwill)	0.0		0.0
Investment in subsidiary	1,456.4		1,761.9
Other assets	1,456.4		1,761.9
Total assets
Operating Lease, Liability, Current			0.0
Billings in Excess of Cost, Noncurrent	0.0		0.0
Billings in Excess of Cost, Current	0.0
Provision for Loss on Contracts	0.0		0.0
Operating Lease, Liability, Noncurrent			0.0
Provision for Loss on Contacts, Non Current	0.0		0.0
Deferred Tax Liabilities, Net, Noncurrent	0.0		0.0
Total equity	1,456.4		1,761.9
Total liabilities and equity	1,456.4		1,761.9
Investing activities
Payments for (Proceeds from) Other Investing Activities		0.0
Payments to Acquire Businesses, Net of Cash Acquired	0.0
Payments for (Proceeds from) Other Investing Activities	0.0
Proceeds from (Payments for) Other Financing Activities	0.0
Financing activities
Early Repayment of Senior Debt		0.0
Collection on (repayment of) intercompany debt		0.0
Payment, Tax Withholding, Share-based Payment Arrangement	0.0	0.0
Proceeds (payments) from subsidiary for purchase of treasury stock		(75.0)
Debt issuance and financing costs	0.0
Payments for Repurchase of Common Stock		75.0
Proceeds from subsidiary (payments to Parent) to pay dividends	12.4	12.7
Payments of Dividends	(12.4)	(12.7)
Proceeds from Stock Plans	0.0
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	230.9	256.8
Operating costs and expenses
Cost of sales	206.4	215.9
Selling, general and administrative	5.0	4.0
Restructuring Charges	0.0
Research and development	0.6	1.1
Total operating costs and expenses	212.0	221.0
Operating income	18.9	35.8
Interest expense and financing fee amortization	(0.9)	(1.0)
Other expense, net	6.1	(1.6)
Income (loss) before income taxes and equity in net loss of affiliates and subsidiaries	24.1	33.2
Income tax benefit (provision)	(3.6)	(5.3)
Income (loss) Before Equity In Net Income (Loss) Of Affiliates and Subsidiaries	20.5	27.9
Equity in net loss of affiliate	(1.5)
Net (loss) income	19.0	27.9
Total other comprehensive income (loss)	24.5	10.4
Comprehensive Income, Net of Tax, Attributable to Parent	43.5	38.3
Assets
Cash and cash equivalents	116.7	67.4	157.2	68.6
Restricted Cash and Cash Equivalents	0.0		0.0
Accounts receivable, net	301.2		250.7
Unbilled Receivables, Current	52.7		69.5
Inventory	190.9		195.2
Other current assets	4.3		5.2
Total current assets	665.7		677.8
Property, plant and equipment, net	183.6		192.4
Operating Lease, Right-of-Use Asset	0.2		0.2
Unbilled Receivable, Non Current	6.8		0.0
Pension assets	23.6		24.9
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	0.2		0.2
Goodwill	2.3		2.4
Intangible Assets, Net (Excluding Goodwill)	0.0		0.0
Deferred income taxes	113.7		116.0
Other assets	996.1		1,013.9
Total assets
Liabilities	180.0		175.1
Accounts payable	34.0		29.4
Accrued expenses	2.2		7.6
Profit sharing	1.7		1.6
Operating Lease, Liability, Current	0.0		0.1
Billings in Excess of Cost, Noncurrent	0.0		0.0
Billings in Excess of Cost, Current	0.0		0.0
Provision for Loss on Contracts	0.0		0.0
Forward loss provision, short-term	0.3		0.3
Deferred grant income liability — current	9.8		11.5
Other current liabilities	228.0		225.6
Long-term debt	94.7		94.7
Operating Lease, Liability, Noncurrent	0.1		0.1
Provision for Loss on Contacts, Non Current	0.0		0.0
Deferred grant income liability — non-current	18.3		19.8
Deferred revenue and other deferred credits	5.4		4.0
Deferred Tax Liabilities, Net, Noncurrent	8.2		8.3
Deferred income taxes	5.9		6.3
Total equity	635.5		655.1
Total liabilities and equity	996.1		1,013.9
Operating activities
Net cash (used in) operating activities	(28.6)	41.5
Investing activities
Purchase of property, plant and equipment	(7.2)	(8.2)
Payments for (Proceeds from) Other Investing Activities		0.0
Payments to Acquire Businesses, Net of Cash Acquired	0.0
Payments for (Proceeds from) Other Investing Activities	(1.5)
Net cash used in investing activities	(5.7)	(8.2)
Proceeds from Lines of Credit		0.0
Proceeds from (Payments for) Other Financing Activities	0.0
Financing activities
Principal payments of debt	(0.3)
Early Repayment of Senior Debt		0.2
Collection on (repayment of) intercompany debt	0.3	34.0
Payment, Tax Withholding, Share-based Payment Arrangement	0.0	0.0
Proceeds (payments) from subsidiary for purchase of treasury stock		0.0
Debt issuance and financing costs	0.0
Payments for Repurchase of Common Stock		0.0
Proceeds from subsidiary (payments to Parent) to pay dividends	0.0	0.0
Payments of Dividends	0.0	0.0
Proceeds from Stock Plans	0.0
Net cash (used in) provided by financing activities		(34.2)
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	(40.5)	(1.2)
Cash and cash equivalents, beginning of period	157.2
Cash, cash equivalents, and restricted cash, end of period	116.6
Subsidiary Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	899.2	1,765.2
Operating costs and expenses
Cost of sales	962.7	1,500.3
Selling, general and administrative	68.1	56.5
Restructuring Charges	42.6
Research and development	11.6	11.4
Total operating costs and expenses	1,085.0	1,568.2
Operating income	(185.8)	197.0
Interest expense and financing fee amortization	(32.1)	(18.8)
Other expense, net	(54.3)	(8.4)
Income (loss) before income taxes and equity in net loss of affiliates and subsidiaries	(272.2)	169.8
Income tax benefit (provision)	90.3	(34.7)
Income (loss) Before Equity In Net Income (Loss) Of Affiliates and Subsidiaries	(181.9)	135.1
Equity in net income of subsidiaries	21.2	29.8
Net (loss) income	(160.7)	164.9
Total other comprehensive income (loss)	(141.7)	10.0
Comprehensive Income, Net of Tax, Attributable to Parent	(302.4)	174.9
Assets
Cash and cash equivalents	1,733.7	1,177.6	2,210.0	$ 725.5
Restricted Cash and Cash Equivalents	0.3		0.3
Accounts receivable, net	480.1		565.4
Unbilled Receivables, Current	328.2		458.8
Inventory	832.8		786.8
Other current assets	129.7		93.5
Total current assets	3,488.1		4,098.1
Property, plant and equipment, net	1,773.9		1,773.0
Operating Lease, Right-of-Use Asset	40.0		41.2
Unbilled Receivable, Non Current	3.6		6.4
Pension assets	259.0		424.2
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	192.4		106.3
Goodwill	76.2		0.0
Intangible Assets, Net (Excluding Goodwill)	30.6		1.2
Investment in subsidiary	821.0		838.4
Deferred income taxes	152.7		147.6
Other assets	6,837.5		7,436.4
Total assets
Liabilities	660.4		977.1
Accounts payable	251.0		210.0
Accrued expenses	15.4		76.9
Profit sharing	50.8		48.4
Operating Lease, Liability, Current	5.3		5.3
Operating lease liabilities, short-term	17.8		21.6
Billings in Excess of Cost, Noncurrent	388.9		356.3
Billings in Excess of Cost, Current	166.9		158.3
Provision for Loss on Contracts	91.5		83.9
Forward loss provision, short-term	17.6		14.5
Deferred grant income liability — current	27.2		29.3
Other current liabilities	1,303.9		1,625.3
Long-term debt	2,968.9		2,974.7
Operating Lease, Liability, Noncurrent	34.9		36.0
Advance payments, long-term	327.3		333.3
Pension/OPEB obligation	50.9		35.7
Provision for Loss on Contacts, Non Current	146.9		163.5
Deferred grant income liability — non-current	9.1		9.2
Deferred revenue and other deferred credits	31.4		30.4
Deferred Tax Liabilities, Net, Noncurrent	0.0		0.0
Deferred income taxes	199.0		190.1
Total equity	1,376.3		1,681.9
Total liabilities and equity	6,837.5		7,436.4
Operating activities
Net cash (used in) operating activities	(312.5)	197.4
Investing activities
Purchase of property, plant and equipment	(23.4)	(29.3)
Payments for (Proceeds from) Other Investing Activities		0.1
Payments to Acquire Businesses, Net of Cash Acquired	(118.1)
Payments for (Proceeds from) Other Investing Activities	0.3
Net cash used in investing activities	(141.2)	(29.2)
Proceeds from Lines of Credit		100.0
Proceeds from (Payments for) Other Financing Activities	10.0
Proceeds from Issuance of Senior Long-term Debt		250.0
Financing activities
Principal payments of debt	(7.0)
Repayments of Debt	(5.7)
Early Repayment of Senior Debt		(2.4)
Collection on (repayment of) intercompany debt	9.1	34.0
Payment, Tax Withholding, Share-based Payment Arrangement	(13.1)	(10.0)
Proceeds (payments) from subsidiary for purchase of treasury stock		75.0
Debt issuance and financing costs	(4.8)
Payments for Repurchase of Common Stock		0.0
Proceeds from subsidiary (payments to Parent) to pay dividends	(12.4)	(12.7)
Payments of Dividends	0.0	0.0
Proceeds from Stock Plans	(1.3)
Net cash (used in) provided by financing activities	(22.6)	283.9
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(476.3)	452.1
Cash and cash equivalents, beginning of period	2,193.3
Cash, cash equivalents, and restricted cash, end of period	1,717.0
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	111.2	116.4
Operating costs and expenses
Cost of sales	107.4	112.7
Selling, general and administrative	0.8	0.8
Restructuring Charges	0.0
Research and development	0.1	0.4
Total operating costs and expenses	108.3	113.9
Operating income	2.9	2.5
Interest expense and financing fee amortization	0.0
Other expense, net	0.0
Income (loss) before income taxes and equity in net loss of affiliates and subsidiaries	2.9	2.5
Income tax benefit (provision)	0.7	(0.6)
Income (loss) Before Equity In Net Income (Loss) Of Affiliates and Subsidiaries	2.2	1.9
Equity in net loss of affiliate	0.0
Equity in net income of subsidiaries	0.0
Net (loss) income	2.2	1.9
Total other comprehensive income (loss)	0.0
Comprehensive Income, Net of Tax, Attributable to Parent	2.2	1.9
Assets
Restricted Cash and Cash Equivalents	0.0		0.0
Accounts receivable, net	52.6		50.5
Unbilled Receivables, Current	0.0		0.0
Inventory	145.0		136.8
Other current assets	0.0
Total current assets	197.6		187.3
Property, plant and equipment, net	295.7		306.3
Operating Lease, Right-of-Use Asset	7.3		7.5
Unbilled Receivable, Non Current	0.0		0.0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent			0.0
Goodwill	0.0		0.0
Intangible Assets, Net (Excluding Goodwill)	0.0		0.0
Other assets	500.6		501.1
Total assets
Liabilities	225.6		226.3
Accounts payable	1.1		0.8
Profit sharing	0.2		0.2
Operating Lease, Liability, Current	0.6		0.6
Billings in Excess of Cost, Noncurrent	0.0		0.0
Billings in Excess of Cost, Current	0.0
Provision for Loss on Contracts	0.0		0.0
Deferred grant income liability — current			2.1
Other current liabilities	227.5		230.0
Long-term debt	0.8		0.9
Operating Lease, Liability, Noncurrent	6.7		6.9
Provision for Loss on Contacts, Non Current	0.0		0.0
Deferred Tax Liabilities, Net, Noncurrent	0.0		0.0
Total equity	265.6		263.3
Total liabilities and equity	500.6		$ 501.1
Operating activities
Net cash (used in) operating activities	9.8	3.3
Investing activities
Purchase of property, plant and equipment	(0.4)	(3.3)
Payments for (Proceeds from) Other Investing Activities		0.0
Payments to Acquire Businesses, Net of Cash Acquired	0.0
Net cash used in investing activities	(0.4)	(3.3)
Proceeds from Lines of Credit		0.0
Proceeds from (Payments for) Other Financing Activities	0.0
Financing activities
Repayments of Debt	0.0
Early Repayment of Senior Debt		0.0
Collection on (repayment of) intercompany debt	(9.4)	0.0
Payment, Tax Withholding, Share-based Payment Arrangement	0.0	0.0
Proceeds (payments) from subsidiary for purchase of treasury stock		0.0
Debt issuance and financing costs	0.0
Payments for Repurchase of Common Stock		0.0
Proceeds from subsidiary (payments to Parent) to pay dividends	0.0	0.0
Payments of Dividends	0.0	$ 0.0
Proceeds from Stock Plans	0.0
Net cash (used in) provided by financing activities	(9.4)
Cash, cash equivalents, and restricted cash, end of period	$ 0.0