Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Apr. 02, 2020	Dec. 31, 2019	Mar. 28, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 1,833.6	$ 2,350.5	$ 1,228.4	$ 773.6
Restricted Cash, Current	0.3	0.3	$ 0.3	$ 0.3
Accounts receivable, net	508.6	546.4
Unbilled Receivables, Current	380.9	528.3
Inventory, net	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, 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
Liabilities Noncurrent
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
Billings in Excess of Cost, Noncurrent	388.9	356.3
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 income taxes	104.3	95.8
Deferred Tax Liabilities, Net, Noncurrent	8.2	8.3
Additional Paid in Capital [Abstract]
Additional paid-in capital	1,125.6	1,125.0
AccumulatedOtherComprehensiveIncomeLossNetOfTaxAbstract
Accumulated other comprehensive loss	(250.9)	(109.2)
Retained Earnings Accumulated Deficit [Abstract]
Retained earnings	3,036.9	3,201.3
Treasury Stock, Value	(2,456.8)	(2,456.8)
Total stockholders' equity	1,455.9	1,761.4
Noncontrolling interest	0.5	0.5
Total equity	1,456.4	1,761.9
Total liabilities and equity	7,001.1	7,606.0
Class A [Member]
Stockholders' Equity Attributable to Parent [Abstract]
Common stock	$ 1.1	$ 1.1