Spirit AeroSystems (SPR) 10-Q 3 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Oct. 01, 2020	Oct. 23, 2020
Cover [Abstract]
Security Exchange Name	NYSE
Title of 12(b) Security	Class A common stock, par value $0.01 per share
Entity Address, Postal Zip Code	67210
City Area Code	316
Local Phone Number	526-9000
Entity Address, State or Province	KS
Entity Address, City or Town	Wichita
Entity Address, Address Line One	3801 South Oliver
Entity Tax Identification Number	20-2436320
Entity Incorporation, State or Country Code	DE
Entity File Number	001-33160
Document Transition Report	false
Document Quarterly Report	true
Entity Registrant Name	Spirit AeroSystems Holdings, Inc.
Entity Central Index Key	0001364885
Document Type	10-Q
Document Period End Date	Oct. 1, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Amendment Flag	false
Trading Symbol	SPR
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		105,637,271

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019
Income Statement [Abstract]
Revenues	$ 806.3	$ 1,919.9	$ 2,528.2	$ 5,903.8
Operating costs and expenses
Cost of sales	903.4	1,647.6	2,941	5,029.1
Selling, general and administrative	52.8	53.6	179.2	173.6
Restructuring Charges	19.5	0	68.4	0
Research and development	7.5	12.6	28.1	36
Gain (Loss) on Disposition of Property Plant Equipment	0	0	22.9	0
Total operating costs and expenses	983.2	1,713.8	3,239.6	5,238.7
Operating (loss) income	(176.9)	206.1	(711.4)	665.1
Interest expense and financing fee amortization	(53)	(23.6)	(133.8)	(66.1)
Other expense, net	10	9.5	65.4	11.9
(Loss) income before income taxes and equity in net (loss) income of affiliate	(239.9)	173	(910.6)	587.1
Income tax benefit (provision)	85.2	(41.7)	340	(124.7)
(Loss) income before equity in net (loss) income of affiliate	(154.7)	131.3	(570.6)	462.4
Equity in net loss of affiliate	(0.8)	0	(3.8)	0
Net (loss) income	$ (155.5)	$ 131.3	$ (574.4)	$ 462.4
(Loss) earnings per share
Earnings Per Share, Basic	$ (1.50)	$ 1.27	$ (5.53)	$ 4.46
Diluted (in dollars per share)	$ (1.50)	$ 1.26	$ (5.53)	$ 4.41

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (155.5)	$ 131.3	$ (574.4)	$ 462.4
Foreign currency translation adjustments	17.3	(12.8)	(15.6)	(16.7)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	23.8	36.9	(3)	36.2
Unrealized foreign exchange (loss) gain on intercompany loan, net of tax effect of ($0.4) and $0.2 for the three months ended, respectively, and $0.4 and $0.3 for the nine months ended, respectively	1.4	(1.1)	(1.2)	(1.3)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax	0	(1.5)	(10.9)	(1.5)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	9.2	0	10.3	0
Total other comprehensive (loss) gain	51.7	21.5	(20.4)	16.7
Total comprehensive (loss) income	$ (103.8)	$ 152.8	$ (594.8)	$ 479.1

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Unaudited) (Parentheticals) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019
Statement of Comprehensive Income [Abstract]
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	$ (7.4)	$ (11.4)	$ 0.9	$ (11.2)
Unrealized exchange (loss) on intercompany loan, tax	(0.4)	0.2	0.4	0.3
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	(2.8)	0	(3.1)	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	$ 0	$ 0	$ (3.3)	$ 0

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Oct. 01, 2020	Dec. 31, 2019	Sep. 26, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 1,441.3	$ 2,350.5	$ 1,477.3	$ 773.6
Restricted Cash, Current	1.3	0.3	$ 0.3	$ 0.3
Accounts receivable, net	388.8	546.4
Unbilled Receivables, Current	333.6	528.3
Inventory, net	1,183.3	1,118.8
Other current assets	259.6	98.7
Total current assets	3,607.9	4,643
Property, plant and equipment, net	2,147.4	2,271.7
Operating Lease, Right-of-Use Asset	44.4	48.9
Unbilled Receivable, Non Current	4.1	6.4
Pension assets	404.2	449.1
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	136.7	106.5
Goodwill	78.4	2.4
Intangible Assets, Net (Excluding Goodwill)	29.5	1.2
Deferred income taxes	151.8	76.8
Other assets	6,604.4	7,606
Total assets
Liabilities	483.1	1,058.3
Accounts payable	289.8	240.2
Accrued expenses	38.1	84.5
Profit sharing	335.5	50.2
Operating Lease, Liability, Current	5.5	6
Operating lease liabilities, short-term	20.1	21.6
Billings in Excess of Cost, Current	100.9	158.3
Provision for Loss on Contracts	169.9	83.9
Forward loss provision, short-term	15.7	14.8
Deferred grant income liability — current	37.7	42.9
Other current liabilities	1,496.3	1,760.7
Liabilities Noncurrent
Long-term debt	2,659	2,984.1
Operating Lease, Liability, Noncurrent	39.1	43
Advance payments, long-term	325	333.3
Pension/OPEB obligation	47	35.7
Billings in Excess of Cost, Noncurrent	371.7	356.3
Provision for Loss on Contacts, Non Current	303.8	163.5
Deferred grant income liability - non-current	27.4	29
Deferred revenue and other deferred credits	33.6	34.4
Deferred income taxes	119.5	95.8
Deferred Tax Liabilities, Net, Noncurrent	10	8.3
Additional Paid in Capital [Abstract]
Additional paid-in capital	1,133.2	1,125
AccumulatedOtherComprehensiveIncomeLossNetOfTaxAbstract
Accumulated other comprehensive loss	(129.6)	(109.2)
Retained Earnings Accumulated Deficit [Abstract]
Retained earnings	$ 2,623.5	$ 3,201.3
Treasury Stock, Shares	41,523,470	41,523,470
Treasury Stock, Value	$ (2,456.7)	$ (2,456.8)
Total stockholders' equity	1,171.5	1,761.4
Noncontrolling interest	0.5	0.5
Total equity	1,172	1,761.9
Total liabilities and equity	6,604.4	7,606
Class A [Member]
Stockholders' Equity Attributable to Parent [Abstract]
Common stock	$ 1.1	$ 1.1
Retained Earnings Accumulated Deficit [Abstract]
Common Stock, Shares Authorized	200,000,000	200,000,000
Class B [Member]
Retained Earnings Accumulated Deficit [Abstract]
Common Stock, Shares Authorized	150,000,000	150,000,000

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Oct. 01, 2020	Dec. 31, 2019
Shareholders' equity
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Treasury Stock, Shares	41,523,470	41,523,470
Class A [Member]
Shareholders' equity
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	105,660,882	104,882,379
Class B [Member]
Shareholders' equity
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	0	0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019
Operating activities
Net (loss) income	$ (574.4)	$ 462.4
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities
Depreciation and amortization expense	202.5	187
Amortization of deferred financing fees	12.6	2.6
Accretion of customer supply agreement	1.6	3.3
Employee Benefit and Share-based Payment Arrangement, Noncash	17.1	22.6
Loss on Derivative Instruments, Pretax	0	8.1
Gain from foreign currency transactions	(1.1)	17.2
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property	(24.9)	(0.7)
Deferred taxes	(34.3)	29.4
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits	57.2	(9.7)
Grant liability amortization	(3.2)	(13.8)
Unrealized Gain (Loss) on Investments	3.8	0
Increase (Decrease) in Forward Provision	226.3	(7.5)
Changes in assets and liabilities
Accounts receivable, net	169.3	(167.8)
Inventory, net	(66.1)	(3.3)
Increase (Decrease) in Unbilled Receivables	200.4	(67.5)
Accounts payable and accrued liabilities	(530.6)	149.3
Profit sharing/deferred compensation	(46.2)	(12.2)
Advance payments	(19.9)	120.8
Income taxes receivable/payable	(252.6)	4.9
Increase (Decrease) in Billing in Excess of Cost of Earnings	(44.1)	(16.7)
Deferred revenue and other deferred credits	2	6.2
Other	42	2.6
Net cash (used in) provided by operating activities	(612.8)	718.6
Investing activities
Purchase of property, plant and equipment	(70.4)	(118.8)
Payments to Acquire Businesses, Net of Cash Acquired	(117.9)	0
Payments for (Proceeds from) Other Investing Activities	4.9	0.1
Net cash used in investing activities	(183.4)	(118.7)
Financing activities
Proceeds from Lines of Credit	0	100
Proceeds from Issuance of Senior Long-term Debt	1,200	250
Principal payments of debt	(22.7)	(8.5)
Repayments of Debt	(439.7)	(5.2)
Repayments of Lines of Credit	(800)	(100)
Payment, Tax Withholding, Share-based Payment Arrangement	(14)	(12.1)
Proceeds from Stock Plans	2.6	1.3
Debt issuance and financing costs	(27.6)	0
Proceeds from (Repurchase of) Equity	0.1
Payments for Repurchase of Common Stock		(75)
Payments of Dividends	(14.4)	(37.8)
Proceeds from (Payments for) Other Financing Activities	0.1	0.8
Net cash (used in ) provided by financing activities	(105.6)	113.5
Effect of exchange rate changes on cash and cash equivalents	(3.3)	(13.5)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(905.1)	699.9
Cash, cash equivalents, and restricted cash, beginning of period	2,367.2	794.1
Cash, cash equivalents, and restricted cash, end of period	1,441.3	1,477.3
Reconciliation of Cash, Cash Equivalents, and Restricted Cash [Abstract]
Restricted Cash, Current	1.3	0.3
Restricted Cash, Noncurrent	$ 19.5	$ 16.4

Condensed Statement of Changes

Condensed Statement of Changes in Stockholders' Equity Statement - USD ($) $ in Millions	Total	Class A [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock, Common [Member]	AOCI Including Portion Attributable to Noncontrolling Interest [Member]	Stockholders' Equity, Total [Member]
Stockholders' Equity Attributable to Parent at Dec. 31, 2018								$ 1,237.6
Common Stock, Shares, Outstanding at Dec. 31, 2018			105,461,817
Common Stock, Value, Outstanding at Dec. 31, 2018			$ 1.1
Additional Paid in Capital, Common Stock at Dec. 31, 2018				$ 1,100.9
Treasury Stock, Value at Dec. 31, 2018						$ (2,381)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Dec. 31, 2018							$ (196.6)
Retained Earnings (Accumulated Deficit) at Dec. 31, 2018					$ 2,713.2
Common Stock, Dividends, Per Share, Declared	$ 0.12
Net Income (Loss) Attributable to Parent					331.1			331.1
Impact on Retained Earnings, Adoption of ASC 606								0
Reclassification of Stranded tax effects related to TCJA					8.3		(8.3)
Dividends, Common Stock, Cash					(25.3)			(25.3)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			392,933
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture			$ 0
Stock Issued During Period, Value, Restricted Stock Award, Gross				15.1				15.1
Shares Issued, Shares, Share-based Payment Arrangement, Forfeited			(97,154)
Shares Granted, Value, Share-based Payment Arrangement, Forfeited			$ 0
Payment, Tax Withholding, Share-based Payment Arrangement			$ 0	(11.8)				(11.8)
Stock Issued During Period, Shares, Employee Stock Purchase Plans			14,617
Stock Issued During Period, Value, Employee Stock Purchase Plan				1.3				1.3
Supplemental Retirement Plan Shares Issued			6,214
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation			(126,808)
Treasury Stock, Shares, Acquired			(796,409)
Treasury Stock, Value, Acquired, Cost Method			$ (0.1)			(75)		(75.1)
Other Comprehensive Income (Loss), Net of Tax							(4.7)	(4.7)
Stockholders' Equity Attributable to Parent at Jun. 27, 2019								1,468.2
Common Stock, Shares, Outstanding at Jun. 27, 2019			104,855,210
Additional Paid in Capital, Common Stock at Jun. 27, 2019				1,105.5
Treasury Stock, Value at Jun. 27, 2019						(2,456)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Jun. 27, 2019							(209.6)
Retained Earnings (Accumulated Deficit) at Jun. 27, 2019					3,027.3
Common Stock, Value, Outstanding at Jun. 27, 2019			$ 1
Stockholders' Equity Attributable to Parent at Dec. 31, 2018								1,237.6
Common Stock, Shares, Outstanding at Dec. 31, 2018			105,461,817
Common Stock, Value, Outstanding at Dec. 31, 2018			$ 1.1
Additional Paid in Capital, Common Stock at Dec. 31, 2018				1,100.9
Treasury Stock, Value at Dec. 31, 2018						(2,381)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Dec. 31, 2018							(196.6)
Retained Earnings (Accumulated Deficit) at Dec. 31, 2018					2,713.2
Net Income (Loss) Attributable to Parent	$ 462.4
Payment, Tax Withholding, Share-based Payment Arrangement	12.1
Other Comprehensive Income (Loss), Net of Tax	$ 16.7
Stockholders' Equity Attributable to Parent at Sep. 26, 2019								1,616.5
Common Stock, Shares, Outstanding at Sep. 26, 2019			104,888,051
Additional Paid in Capital, Common Stock at Sep. 26, 2019				1,113.4
Treasury Stock, Value at Sep. 26, 2019						(2,456)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Sep. 26, 2019							(188.1)
Retained Earnings (Accumulated Deficit) at Sep. 26, 2019					3,146.2
Common Stock, Value, Outstanding at Sep. 26, 2019			$ 1
Stockholders' Equity Attributable to Parent at Jun. 27, 2019								1,468.2
Common Stock, Shares, Outstanding at Jun. 27, 2019			104,855,210
Additional Paid in Capital, Common Stock at Jun. 27, 2019				1,105.5
Treasury Stock, Value at Jun. 27, 2019						(2,456)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Jun. 27, 2019							(209.6)
Retained Earnings (Accumulated Deficit) at Jun. 27, 2019					3,027.3
Common Stock, Dividends, Per Share, Declared	$ 0.12
Net Income (Loss) Attributable to Parent	$ 131.3				131.3			131.3
Dividends, Common Stock, Cash					(12.4)			(12.4)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			37,841
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture			$ 0
Stock Issued During Period, Value, Restricted Stock Award, Gross				8.2				8.2
Shares Issued, Shares, Share-based Payment Arrangement, Forfeited			(2,568)
Shares Granted, Value, Share-based Payment Arrangement, Forfeited			$ 0
Payment, Tax Withholding, Share-based Payment Arrangement			$ 0	(0.3)				(0.3)
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation			(2,432)
Other Comprehensive Income (Loss), Net of Tax	21.5						21.5	21.5
Stockholders' Equity Attributable to Parent at Sep. 26, 2019								1,616.5
Common Stock, Shares, Outstanding at Sep. 26, 2019			104,888,051
Additional Paid in Capital, Common Stock at Sep. 26, 2019				1,113.4
Treasury Stock, Value at Sep. 26, 2019						(2,456)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Sep. 26, 2019							(188.1)
Retained Earnings (Accumulated Deficit) at Sep. 26, 2019					3,146.2
Common Stock, Value, Outstanding at Sep. 26, 2019			$ 1
Stockholders' Equity Attributable to Parent at Dec. 31, 2019	1,761.4							1,761.4
Common Stock, Shares, Outstanding at Dec. 31, 2019			104,882,379
Common Stock, Value, Outstanding at Dec. 31, 2019		$ 1.1	$ 1.1
Additional Paid in Capital, Common Stock at Dec. 31, 2019	1,125			1,125
Treasury Stock, Value at Dec. 31, 2019	2,456.8					(2,456.8)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Dec. 31, 2019	(109.2)						(109.2)
Retained Earnings (Accumulated Deficit) at Dec. 31, 2019	3,201.3				3,201.3
Net Income (Loss) Attributable to Parent					(418.9)			(418.9)
Dividends, Common Stock, Cash					(2.4)			(2.4)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			972,614
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture			$ 0
Stock Issued During Period, Value, Restricted Stock Award, Gross				13.3				13.3
Shares Issued, Shares, Share-based Payment Arrangement, Forfeited			(87,903)
Shares Granted, Value, Share-based Payment Arrangement, Forfeited			$ 0
Payment, Tax Withholding, Share-based Payment Arrangement			$ 0	(13.7)				(13.7)
Stock Issued During Period, Shares, Employee Stock Purchase Plans			55,656
Stock Issued During Period, Value, Employee Stock Purchase Plan				1.3				1.3
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation			(197,918)
Treasury Stock, Value, Acquired, Cost Method						0.1		0.1
Other Comprehensive Income (Loss), Net of Tax							(72.1)	(72.1)
Stockholders' Equity Attributable to Parent at Jul. 02, 2020								1,269
Common Stock, Shares, Outstanding at Jul. 02, 2020			105,624,828
Additional Paid in Capital, Common Stock at Jul. 02, 2020				1,125.9
Treasury Stock, Value at Jul. 02, 2020						(2,456.7)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Jul. 02, 2020							(181.3)
Retained Earnings (Accumulated Deficit) at Jul. 02, 2020					2,780
Common Stock, Value, Outstanding at Jul. 02, 2020			$ 1.1
Stockholders' Equity Attributable to Parent at Dec. 31, 2019	1,761.4							1,761.4
Common Stock, Shares, Outstanding at Dec. 31, 2019			104,882,379
Common Stock, Value, Outstanding at Dec. 31, 2019		$ 1.1	$ 1.1
Additional Paid in Capital, Common Stock at Dec. 31, 2019	1,125			1,125
Treasury Stock, Value at Dec. 31, 2019	2,456.8					(2,456.8)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Dec. 31, 2019	(109.2)						(109.2)
Retained Earnings (Accumulated Deficit) at Dec. 31, 2019	3,201.3				3,201.3
Net Income (Loss) Attributable to Parent	(574.4)
Payment, Tax Withholding, Share-based Payment Arrangement	14
Other Comprehensive Income (Loss), Net of Tax	(20.4)
Stockholders' Equity Attributable to Parent at Oct. 01, 2020	1,171.5							1,171.5
Common Stock, Shares, Outstanding at Oct. 01, 2020			105,660,882
Additional Paid in Capital, Common Stock at Oct. 01, 2020	1,133.2			1,133.2
Treasury Stock, Value at Oct. 01, 2020	2,456.7					(2,456.7)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Oct. 01, 2020	(129.6)						(129.6)
Retained Earnings (Accumulated Deficit) at Oct. 01, 2020	$ 2,623.5				2,623.5
Common Stock, Value, Outstanding at Oct. 01, 2020			$ 1.1
Stockholders' Equity Attributable to Parent at Jul. 02, 2020								1,269
Common Stock, Shares, Outstanding at Jul. 02, 2020			105,624,828
Additional Paid in Capital, Common Stock at Jul. 02, 2020				1,125.9
Treasury Stock, Value at Jul. 02, 2020						(2,456.7)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Jul. 02, 2020							(181.3)
Retained Earnings (Accumulated Deficit) at Jul. 02, 2020					2,780
Common Stock, Dividends, Per Share, Declared	$ 0.01
Net Income (Loss) Attributable to Parent	$ (155.5)				(155.5)			(155.5)
Dividends, Common Stock, Cash					(1)			(1)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			7,657
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture			$ 0
Stock Issued During Period, Value, Restricted Stock Award, Gross				6.3				6.3
Shares Issued, Shares, Share-based Payment Arrangement, Forfeited			(30,906)
Shares Granted, Value, Share-based Payment Arrangement, Forfeited			$ 0
Payment, Tax Withholding, Share-based Payment Arrangement				(0.3)				(0.3)
Stock Issued During Period, Shares, Employee Stock Purchase Plans			68,810
Stock Issued During Period, Value, Employee Stock Purchase Plan				1.3				1.3
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation			(9,507)
Other Comprehensive Income (Loss), Net of Tax	51.7						51.7	51.7
Stockholders' Equity Attributable to Parent at Oct. 01, 2020	1,171.5							$ 1,171.5
Common Stock, Shares, Outstanding at Oct. 01, 2020			105,660,882
Additional Paid in Capital, Common Stock at Oct. 01, 2020	1,133.2			$ 1,133.2
Treasury Stock, Value at Oct. 01, 2020	2,456.7					$ (2,456.7)
Accumulated Other Comprehensive Income (Loss), Net of Tax at Oct. 01, 2020	(129.6)						$ (129.6)
Retained Earnings (Accumulated Deficit) at Oct. 01, 2020	$ 2,623.5				$ 2,623.5
Common Stock, Value, Outstanding at Oct. 01, 2020			$ 1.1

Organization and Basis of Inter

Organization and Basis of Interim Presentation	9 Months Ended
	Oct. 01, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Interim Presentation	Organization, Basis of Interim Presentation and Recent Developments Spirit AeroSystems Holdings, Inc. (“Holdings” or the “Company”) provides manufacturing and design expertise in a wide range of fuselage, propulsion, and wing products and services for aircraft original equipment manufacturers (“OEM”) and operators through its subsidiary, Spirit AeroSystems, Inc. (“Spirit”). The Company's headquarters are in Wichita, Kansas, with manufacturing and assembly facilities in Tulsa and McAlester, Oklahoma; Prestwick, Scotland; Wichita, Kansas; Kinston, North Carolina; Subang, Malaysia; Saint-Nazaire, France; San Antonio, Texas; and Biddeford, Maine (not including new facilities acquired in connection with our acquisition of select assets from Bombardier Inc. and affiliates, as further described in Note 26, Subsequent Events ). The Company has previously announced site consolidation activities, including the McAlester, Oklahoma and San Antonio, Texas sites. The work transfer and closure activities for these sites will take place over the next several months. The accompanying unaudited interim condensed consolidated financial statements include the Company’s financial statements and the financial statements of its majority-owned or controlled subsidiaries and have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and the instructions to Form 10-Q and Article 10 of Regulation S-X. The Company’s fiscal quarters are 13 weeks in length. Since the Company’s fiscal year ends on December 31, the number of days in the Company’s first and fourth quarters varies slightly from year to year. All intercompany balances and transactions have been eliminated in consolidation. As part of the monthly consolidation process, the Company’s international entities that have functional currencies other than the U.S. dollar are translated to U.S. dollars using the end-of-month translation rate for balance sheet accounts and average period currency translation rates for revenue and income accounts. The U.K. and Malaysian subsidiaries use the British pound as their functional currency. All other foreign subsidiaries and branches use the U.S. dollar as their functional currency. In the opinion of management, the accompanying unaudited interim condensed consolidated financial statements contain all adjustments (consisting of normal recurring adjustments and elimination of intercompany balances and transactions) considered necessary to fairly present the results of operations for the interim period. The results of operations for the nine months ended October 1, 2020, are not necessarily indicative of the results that may be expected for the year ending December 31, 2020. In connection with the preparation of the condensed consolidated financial statements, the Company evaluated subsequent events through the date the financial statements were issued. The interim financial statements should be read in conjunction with the audited consolidated financial statements, including the notes thereto, included in the Company’s 2019 Annual Report on Form 10-K filed with the Securities and Exchange Commission (the “SEC”) on February 28, 2020 (the “2019 Form 10-K”). The Company's significant accounting policies are described in Note 3, Summary of Significant Accounting Policies to our consolidated financial statements in the 2019 Form 10-K. The single update to the significant accounting policies described in the 2019 Form 10-K is related to the impact of adopting ASU No. 2016-13, Financial Instruments - Credit losses (Topic 326) ( “ASU 2016-13”) and is described in detail in Note 2, Adoption of New Accounting Standards , and Note 5, Accounts Receivable and Allowance for Credit Losses . Recent Developments B737MAX . In March 2019, the B737 MAX fleet was grounded in the U.S. and internationally following the 2018 and 2019 accidents involving two B737 MAX aircraft. To date, the fleet remains grounded and the recertification process is continuing. The B737 MAX program is a critical program to the Company and for the twelve months ended December 31, 2019, approximately 53% of the Company’s net revenues were generated from sales of components to The Boeing Company (“Boeing”) for the B737 aircraft. Due to the grounding and the impacts of COVID-19 on the aviation industry, the Company has experienced significant deterioration in its B737 MAX production rates that have reduced the Company’s revenues. A summary of the production rate changes is below. • On April 12, 2019, Boeing and the Company executed a Memorandum of Agreement (the “2019 MOA”) providing that the Company was to maintain its delivery rate of 52 shipsets per month with respect to the B737 MAX. Previously, the Company was expecting to increase production to a rate of 57 shipsets per month in 2019; • On December 19, 2019, Boeing directed the Company to stop all B737 MAX deliveries to Boeing effective January 1, 2020. Accordingly, Spirit suspended all B737 MAX production beginning on January 1, 2020; • On February 6, 2020, Boeing and Spirit entered into a Memorandum of Agreement (the “2020 MOA”) largely superseding the 2019 MOA and providing for Spirit to deliver to Boeing 216 B737 MAX shipsets in 2020; • On May 4, 2020, Boeing and the Company agreed that Spirit would deliver 125 B737 MAX shipsets to Boeing in 2020; and • On June 19, 2020, Boeing directed Spirit to reduce its 2020 B737 production plan from 125 to 72 shipsets. COVID-19 . The COVID-19 pandemic and its effects (including travel advisories, shutdowns or shelter-in-place mandates or recommendations, restrictive protocols, and canceled events) have caused a significant decline in the demand for air travel and, as a result, the Company has experienced a significant deterioration in its revenues during the nine months ended October 1, 2020, resulting in a net loss of $574.4 for that period. The length of the COVID-19 pandemic and its impact on the aviation industry and the Company’s operational and financial performance is uncertain and outside of the Company’s control. The Company expects the pandemic and its effects to continue to have a significant negative impact on its business for the duration of the pandemic and during the subsequent economic recovery, which could be for an extended period of time. The Company has taken several actions to reduce costs, increase liquidity and strengthen its financial position in light of the economic impact of the COVID-19 pandemic, and the B737 MAX grounding and related production changes including the following (certain capitalized terms are defined further below): • Reduced pay for all executives by 20 percent until further notice; • Reduced 2020-2021 term non-employee director compensation by 15 percent; • Reduced planned capital expenditures and operating expenses; • Suspended share repurchase program; • Reduced quarterly dividends to one penny per share; • Initiated multiple production worker furloughs; • Reduced pay for all U.S based, salaried employees and implemented a correlating four-day work week, which remains in place for its salaried workforce at its Wichita, Kansas facility until further notice; • Reduced ~6,600 employees globally including voluntary packages; • Amended and eventually terminated our 2018 Credit Agreement and put into place current Credit Agreement for $400 million; • Issued $1.2 billion in Second Lien 2025 Notes and $500 million in First Lien 2025 Notes; and • Elected to defer the payment of $21.4 in employer payroll taxes incurred through October 1, 2020, as provided by the Coronavirus Aid, Relief, and Economic Security Act (the "CARES Act"), of which 50% is required to be deposited by December 2021 and the remaining 50% by December 2022 and accrued a pre-tax benefit related to the Employee Retention Credit related to paid employee furloughs of approximately $13.6. In addition, as of October 1, 2020 the Company has recorded a deferral of $29.4 of VAT payments until March 2022 under the United Kingdom deferral scheme. The substantial reduction in our production rates for 2020 has significantly reduced revenue received in connection with the B737 MAX program and presents challenges to our liquidity. These challenges are exacerbated by the COVID-19 pandemic as other programs that mitigate the strain of the lower B737 MAX production rate are now suspended or producing at lower rates. The COVID-19 and B737 MAX situations are largely out of our control. If Boeing is unable to return the B737 MAX to service in one or more jurisdictions, begin timely deliveries to customers, or if our customers' production levels across our programs are reduced beyond current expectations due to depressed demand relating to COVID-19 or otherwise, our business, financial condition, results of operations and cash flows could be materially adversely impacted.

Changes in Estimates

Changes in Estimates	9 Months Ended
	Oct. 01, 2020
Changes in Estimates [Abstract]
Change In Estimate [Text Block]	. Changes in EstimatesThe Company has a periodic forecasting process in which management assesses the progress and performance of the Company’s programs. This process requires management to review each program’s progress by evaluating the program schedule, changes to identified risks and opportunities, changes to estimated revenues and costs for the accounting contracts (and options if applicable), and any outstanding contract matters. Risks and opportunities include but are not limited to management’s judgment about the cost associated with the Company’s ability to achieve the schedule, technical requirements (e.g., a newly-developed product versus a mature product), and any other program requirements. Due to the span of years it may take to completely satisfy the performance obligations for the accounting contracts (and options, if any) and the scope and nature of the work required to be performed on those contracts, the estimation of total revenue and costs is subject to many variables and, accordingly, is subject to change based upon judgment. When adjustments in estimated total consideration or estimated total cost are required, any changes from prior estimates for fully satisfied performance obligations are recognized in the current period as a cumulative catch-up adjustment for the inception-to-date effect of such changes. Cumulative catch-up adjustments are driven by several factors including production efficiencies, assumed rate of production, the rate of overhead absorption, changes to scope of work, and contract modifications. During the third quarter ended October 1, 2020, the Company recognized unfavorable changes in estimates of $123.8 million, which included net forward charges of $128.4 million, and favorable cumulative catch-up adjustments related to periods prior to the third quarter of 2020 of $4.6 million. The Company provided previous guidance that disclosed an estimated forecasted forward loss in the third quarter ended October 1, 2020 on the B787 program of $25-$35 million and the A350 program of $13-$20 million based upon data available as of July 2, 2020. Throughout the quarter ended October 1, 2020, the demand for wide body aircraft continued to evolve as a result of uncertainty regarding timing of resolution of the global pandemic. The Company evaluated additional schedule and production demand information received from our customers, market and analyst data including forecasted demand for wide body aircraft, and as a result, adjusted the expected results on the B787 and A350 programs to include a lower rate of production for a longer duration compared to its previous forecast. This resulted in incremental fixed cost absorption on the B787 and A350 programs and as a result, the forward loss recognized was $64.7 million on the B787 program and $44.9 million on the A350 program for the quarter ended October 1, 2020. Additionally, Boeing announced that the combined production rate on the B777/777X program would decrease to 2 APM beginning in 2021. The Company previously disclosed this production volume decrease on the B777/777X program would impact other commercial programs across the Company, and may result in additional forward losses. The forward losses for the quarter ended October 1, 2020 for programs other than the B787 and A350 were $18.8. Changes in estimates are summarized below: For the Three Months Ended For the Nine Months Ended Changes in Estimates October 1, 2020 September 26, 2019 October 1, 2020 September 26, 2019 (Unfavorable) Favorable Cumulative Catch-up Adjustment by Segment Fuselage $ 8.8 $ (14.4) $ (18.9) $ (2.0) Propulsion (4.6) 1.8 (8.6) (1.5) Wing 0.4 (0.4) (3.1) 1.7 Total (Unfavorable) Favorable Cumulative Catch-up Adjustment $ 4.6 $ (13.0) $ (30.6) $ (1.8) Changes in Estimates on Loss Programs (Forward Loss) by Segment Fuselage $ (92.0) $ (18.8) $ (260.3) $ (13.8) Propulsion (14.9) (4.0) (34.2) (3.1) Wing (21.5) (6.0) (47.7) (4.9) Total Changes in Estimates (Forward Loss) on Loss Programs $ (128.4) $ (28.8) $ (342.2) $ (21.8) Total Change in Estimate $ (123.8) $ (41.8) $ (372.8) $ (23.6) EPS Impact (diluted per share based upon 2020 forecasted effective tax rate) $ (0.77) $ (0.31) $ (2.33) $ (0.18)

Accounts Receivable and Allowan

Accounts Receivable and Allowance for Credit Losses Accounts Receivable and Allowance for Credit Loss (Notes)	9 Months Ended
	Oct. 01, 2020
Receivables [Abstract]
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]	. Accounts Receivable and Allowance for Credit Losses Accounts Receivable, net Accounts receivable represent the Company’s unconditional rights to consideration, subject to the payment terms of the contract, for which only the passage of time is required before payment. Unbilled receivables are reflected under contract assets on the balance sheet. Prior periods allowance for credit losses were based on legacy GAAP. Beginning January 1, 2020, management assesses and records an allowance for credit losses using a current expected credit loss ("CECL") model. See Allowance for Credit Losses, below . Accounts receivable, net consists of the following: October 1, December 31, Trade receivables $ 366.9 $ 515.2 Other 26.5 32.6 Less: allowance for doubtful accounts (4.6) (1.4) Accounts receivable, net $ 388.8 $ 546.4 The Company has two agreements to sell, on a revolving basis, certain trade accounts receivable balances with Boeing and Airbus to third party financial institutions. These programs were primarily entered into as a result of Boeing and Airbus seeking payment term extensions with the Company and they continue to allow Spirit to monetize the receivables prior to their payment date, subject to payment of a discount. No guarantees are delivered under the agreements. Our ability to continue using such agreements is primarily dependent upon the strength of Boeing’s and Airbus’s financial condition. Transfers under this agreement are accounted for as sales of receivables resulting in the receivables being derecognized from the Company's balance sheet. For the nine months ended October 1, 2020, $1,516.3 of accounts receivable have been sold via these arrangements. The proceeds from these sales of receivables are included in cash from operating activities in the Consolidated Statement of Cash Flows. The recorded net loss on sale of receivables is $6.7 for the nine months ended October 1, 2020 and is included in Other income and expense. See Note 21, Other (Expense) Income, Net . Allowance for Credit Losses Beginning January 1, 2020, management assesses and records an allowance for credit losses on financial assets within the scope of ASU 2016-13 using the CECL model. Prior periods allowance for credit losses were based on a review of outstanding receivables that are charged off against the allowance after the potential for recovery is considered remote in accordance with legacy GAAP. The amount necessary to adjust the allowance for credit losses to management’s current estimate, as of the reporting date, on these assets is recorded in net income as credit loss expense. All credit losses reported in accordance with ASU 2016-13 were on trade receivables and/or contract assets arising from the Company’s contracts with customers. In determining the appropriate methodology to use within the CECL model for receivables and contract assets arising from the Company’s contracts with customers, the Company considered the risk characteristics of the applicable assets. Spirit segregated the trade receivables and contract assets into “pools” of assets at the major customer level. The Company's assessment was based on similarity of risk characteristics shared by these pool of assets. Management observed that risks for collectability, with regard to the trade receivables and contract assets resulting from contracts with customers include: macro level economic conditions that impact all of Spirit’s customers, macro level market conditions that could impact Spirit’s customers in certain aircraft categories, certain customer specific market conditions, certain customer specific economic conditions, and certain customer specific administrative conditions. The Company selected a loss-rate method for the CECL model, based on the relationship between historical write-offs of receivables and the underlying sales by major customer. Utilizing this model, a historical loss-rate is applied against the amortized cost of applicable assets, at the time the asset is established. The loss rate reflects the Company’s current estimate of the risk of loss (even when that risk is remote) over the expected remaining contractual life of the assets. The Company's policy is to deduct write-offs from the allowance for credit losses account in the period in which the financial assets are deemed uncollectible.

Contract with customer, asset a

Contract with customer, asset and liability (Notes)	9 Months Ended
	Oct. 01, 2020
Revenue from Contract with Customer [Abstract]
contract with customer, asset and liability [Text Block]	Contract Assets and Contract Liabilities Contract assets primarily represent revenues recognized for performance obligations that have been satisfied but for which amounts have not been billed. Contract assets, current are those that are expected to be billed to our customer within 12 months. Contract assets, long-term are those that are expected to be billed to our customer over periods greater than 12 months. No impairments to contract assets were recorded for the period ended October 1, 2020 or the period ended September 26, 2019. See also Note 5, Accounts Receivable and Allowance for Credit Losses . Contract liabilities are established for cash received that is in excess of revenues recognized and are contingent upon the satisfaction of performance obligations. Contract liabilities primarily consist of cash received on contracts for which revenue has been deferred since the receipts are in excess of transaction price resulting from the allocation of consideration based on relative standalone selling price to future units (including those under option that the Company believes are likely to be exercised) with prices that are lower than standalone selling price. These contract liabilities will be recognized earlier if the options are not fully exercised, or immediately, if the contract is terminated prior to the options being fully exercised. October 1, 2020 December 31, 2019 Change Contract assets $ 337.7 $ 534.7 $ (197.0) Contract liabilities (472.6) (514.6) 42.0 Net contract assets (liabilities) $ (134.9) $ 20.1 $ (155.0) For the period ended October 1, 2020, the decrease in contract assets reflects the net impact of less overtime revenue recognition in relation to billed revenues during the period. The decrease in contract liabilities reflects the net impact of less deferred revenues recorded in excess of revenue recognized during the period. The Company recognized $91.0 of revenue that was included in the contract liability balance at the beginning of the period. September 26, 2019 December 31, 2018 Change Contract assets $ 588.7 $ 523.5 $ 65.2 Contract liabilities (510.9) (527.7) 16.8 Net contract assets (liabilities) $ 77.8 $ (4.2) $ 82.0 For the period ended September 26, 2019, the increase in contract assets reflects the net impact of additional revenues recognized in excess of billed revenues during the period. The decrease in contract liabilities reflects the net impact of less deferred revenues recorded in excess of revenue recognized during the period. The Company recognized $109.7 of revenue that was included in the contract liability balance at the beginning of the period.
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block]	October 1, 2020 December 31, 2019 Change Contract assets $ 337.7 $ 534.7 $ (197.0) Contract liabilities (472.6) (514.6) 42.0 Net contract assets (liabilities) $ (134.9) $ 20.1 $ (155.0)

Revenue (Notes)

Revenue (Notes)	9 Months Ended
	Oct. 01, 2020
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	Disaggregation of Revenue The Company disaggregates revenue based on the method of measuring satisfaction of the performance obligation either over time or at a point in time, based upon the location where products and services are transferred to the customer, and based upon major customer. The Company’s principal operating segments and related revenue are noted in Note 22, Segment Information . The following tables show disaggregated revenues for the periods ended October 1, 2020 and September 26, 2019: For the Three Months Ended For the Nine Revenue October 1, September 26, October 1, September 26, Contracts with performance obligations satisfied over time $ 510.6 $ 1,466.9 $ 1,511.9 $ 4,491.8 Contracts with performance obligations satisfied at a point in time 295.7 453.0 1,016.3 1,412.0 Total Revenue $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8 The following table disaggregates revenue by major customer: For the Three Months Ended For the Nine Customer October 1, September 26, October 1, September 26, Boeing $ 493.8 $ 1,542.0 $ 1,539.9 $ 4,705.1 Airbus 160.1 284.1 575.3 934.0 Other 152.4 93.8 413.0 264.7 Total Revenue $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8 The following table disaggregates revenue based upon the location where control of products are transferred to the customer: For the Three Months Ended For the Nine Location October 1, September 26, October 1, September 26, United States $ 642.0 $ 1,620.6 $ 1,936.4 $ 4,935.8 International United Kingdom 103.6 177.4 358.2 577.6 Other 60.7 121.9 233.6 390.4 Total International 164.3 299.3 591.8 968.0 Total Revenue $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8 Remaining Performance Obligations Unsatisfied, or partially unsatisfied, performance obligations that are expected to be recognized in the future are noted in the table below. The Company expects options to be exercised in addition to the amounts presented below: Remaining in 2020 2021 2022 2023 and After Unsatisfied performance obligations $ 579.2 $ 2,755.3 $ 3,707.3 $ 7,466.6

Inventory

Inventory	9 Months Ended
	Oct. 01, 2020
Inventory Disclosure [Abstract]
Inventory	InventoryInventory consists of raw materials used in the production process, work-in-process, which is direct material, direct labor, overhead and purchases, and capitalized preproduction costs. Raw materials are stated at lower of cost (principally on an actual or average cost basis) or net realizable value. Capitalized pre-production costs include certain contract costs, including applicable overhead, incurred before a product is manufactured on a recurring basis. These costs are typically amortized over a period that is consistent with the satisfaction of the underlying performance obligations to which these relate. October 1, December 31, Raw materials $ 304.0 $ 253.1 Work-in-process (1) 838.3 822.8 Finished goods 14.2 14.5 Product inventory 1,156.5 1,090.4 Capitalized pre-production 26.8 28.4 Total inventory, net $ 1,183.3 $ 1,118.8 (1) Work-in-process inventory includes direct labor, direct material, overhead, and purchases on contracts for which revenue is recognized at a point in time as well as sub-assembly parts that have not been issued to production on contracts for which revenue is recognized using the input method. For the periods ended October 1, 2020 and December 31, 2019, work-in-process inventory includes $184.9 and $157.2, respectively, of costs incurred in anticipation of specific contracts and no impairments were recorded in the period. Product inventory, summarized in the table above, is shown net of valuation reserves of $49.2 and $39.0 as of October 1, 2020 and December 31, 2019, respectively. Excess capacity and abnormal production costs are excluded from inventory and recognized as expense in the period incurred. Cost of sales for the three and nine month periods ended October 1, 2020 includes period expense of $72.6 and $228.8, respectively, of excess capacity production costs related to temporary B737 MAX and A320 production schedule changes. Cost of sales also includes abnormal costs related to temporary workforce adjustments as a result of COVID-19 production pause, net of the U.S. employee retention credit and U.K. government subsidies for the three and nine month periods ended October 1, 2020 of $(10.9) and $33.8, respectively.

Leases (Notes)

Leases (Notes)	9 Months Ended
	Oct. 01, 2020
Leases [Abstract]
Leases of Lessee Disclosure [Text Block]	The Company determines if an arrangement is a lease at the inception of a signed agreement. Operating leases are included in right-of-use (“ROU”) assets (long-term), short-term operating lease liabilities, and long-term operating lease liabilities on the Company’s consolidated balance sheet. Finance leases are included in Property, Plant and Equipment, current maturities of long-term debt, and long-term debt. ROU assets represent the right of the Company to use an underlying asset for the length of the lease term, and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and liabilities are recognized at the lease commencement date based on the estimated present value of lease payments over the lease term. To determine the present value of lease payments, the Company uses its estimated incremental borrowing rate or the implicit rate, if readily determinable. The estimated incremental borrowing rate is based on information available at the lease commencement date, including any recent debt issuances and publicly available data for instruments with similar characteristics. The ROU asset also includes any lease payments made and excludes lease incentives. The Company's lease terms may include options to extend or terminate the lease and, when it is reasonably certain that an option will be exercised, those options are included in the net present value calculation. Leases with a term of 12 months or less, which are primarily related to automobiles and manufacturing equipment, are not recorded on the balance sheet. The aggregate amount of lease cost for leases with a term of 12 months or less is not material. The Company has lease agreements that include lease and non-lease components, which are generally accounted for separately. For certain leases (primarily related to IT equipment), the Company does account for the lease and non-lease components as a single lease component. A portfolio approach is applied to effectively account for the ROU assets and liabilities for those specific leases referenced above. The Company does not have any material leases containing variable lease payments or residual value guarantees. The Company also does not have any material subleases. The Company currently has operating and finance leases for items such as manufacturing facilities, corporate offices, manufacturing equipment, transportation equipment, and vehicles. The Company's active leases have remaining lease terms that range between less than one year to 18 years, some of which include options to extend the leases for up to 30 years, and some of which include options to terminate the leases within one year. Components of lease expense: For the Three Months Ended For the Nine October 1, September 26, October 1, September 26, Operating lease cost $ 2.2 $ 2.4 $ 6.6 $ 6.7 Finance lease cost: Amortization of assets 5.7 2.9 16.0 7.1 Interest on lease liabilities 1.6 0.7 4.7 1.7 Total net lease cost $ 9.5 $ 6.0 $ 27.3 $ 15.5 Supplemental cash flow information related to leases was as follows: For the Three Months Ended For the Nine October 1, September 26, October 1, September 26, Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 2.1 $ 2.4 $ 6.5 $ 6.7 Operating cash flows from finance leases $ 1.6 $ 0.8 $ 4.7 $ 1.7 Financing cash flows from finance leases $ 7.7 $ 3.4 $ 21.4 $ 7.2 ROU assets obtained in exchange for lease obligations: Operating leases $ 0.1 $ 0.9 $ 0.3 $ 1.6 Supplemental balance sheet information related to leases: October 1, 2020 December 31, 2019 Finance leases: Property and equipment, gross $ 212.3 $ 165.5 Accumulated amortization (39.6) (23.5) Property and equipment, net $ 172.7 $ 142.0 The weighted average remaining lease term as of October 1, 2020 for operating and finance leases was 9.9 years and 5.6 years, respectively. The weighted average discount rate as of October 1, 2020 for operating and finance leases was 5.6% and 4.4%, respectively. The weighted average remaining lease term as of December 31, 2019 for operating and finance leases was 10.2 years and 6.5 years, respectively. The weighted average discount rate as of December 31, 2019 for operating and finance leases was 5.6% and 4.3%, respectively. See Note 15, Debt , for current and non-current finance lease obligations. There has not been a significant impact on lease terms, costs, cash flows, or balance sheet values, including any impairment of lease assets, as a result of the COVID-19 pandemic. As of October 1, 2020, remaining maturities of lease liabilities were as follows: 2020 2021 2022 2023 2024 2025 and thereafter Total Lease Payments Less: Imputed Interest Total Lease Obligations Operating Leases $ 2.1 $ 7.5 $ 7.2 $ 6.1 $ 5.5 $ 30.3 $ 58.7 $ (14.1) $ 44.6 Financing Leases $ 10.3 $ 40.0 $ 36.1 $ 31.4 $ 25.2 $ 40.2 $ 183.2 $ (21.0) $ 162.2

Advance Payments and Deferred R

Advance Payments and Deferred Revenue/Credits	9 Months Ended
	Oct. 01, 2020
Advance Payments And Deferred Revenue Credits [Abstract]
Advance Payments And Deferred Revenue Credits	Advance Payments Advances on the B787 Program. Boeing has made advance payments to Spirit under the B787 Special Business Provisions and General Terms Agreement (collectively, the “B787 Supply Agreement”) that are required to be repaid to Boeing by way of offset against the purchase price for future shipset deliveries. Advance repayments were initially scheduled to be spread evenly over the remainder of the first 1,000 B787 shipsets delivered to Boeing. On April 8, 2014, the Company signed a memorandum of agreement with Boeing that suspended advance repayments related to the B787 program for a period of twelve months beginning April 1, 2014. Repayment recommenced on April 1, 2015, and any repayments that otherwise would have become due during such twelve-month period will offset the purchase price for shipsets 1,001 through 1,120. On December 21, 2018, the Company signed a memorandum of agreement with Boeing that again suspended the advance repayments beginning with line unit 818. The advance repayments will resume at a lower rate of $0.45 per shipset at line number 1135 and continue through line number 1605. In the event Boeing does not take delivery of a sufficient number of shipsets to repay the full amount of advances prior to the termination of the B787 program or the B787 Supply Agreement, any advances not then repaid will be applied against any outstanding payments then due by Boeing to us, and any remaining balance will be repaid in annual installments of $27 due on December 15th of each year until the advance payments have been fully recovered by Boeing. As of October 1, 2020, the amount of advance payments received from Boeing under the B787 Supply Agreement and not yet repaid was approximately $212.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Oct. 01, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The FASB’s authoritative guidance on fair value measurements defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. It also establishes a fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The guidance discloses three levels of inputs that may be used to measure fair value: Level 1 Quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 1 assets and liabilities include debt and equity securities and derivative contracts that are traded in an active exchange market. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 2 assets and liabilities include debt securities with quoted prices that are traded less frequently than exchange-traded instruments and derivative contracts whose value is determined using a pricing model with inputs that are observable in the market or can be derived principally from or corroborated by observable market data. Observable inputs, such as current and forward interest rates and foreign exchange rates, are used in determining the fair value of the interest rate swaps and foreign currency hedge contracts. Level 3 Unobservable inputs that are supported by little or no market activity and are significant to the fair value of assets and liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. At October 1, 2020, the Company’s long-term debt includes senior secured notes and senior unsecured notes. The estimated fair value of the Company’s debt obligations is based on the quoted market prices for such obligations or the historical default rate for debt with similar credit ratings. The following table presents the carrying amount and estimated fair value of long-term debt (table excludes First Lien 2025 Notes, which were issued after quarter end on October 5, 2020): October 1, 2020 December 31, 2019 Carrying Fair Carrying Fair 2018 Term Loan and 2018 DDTL (including current portion) $ — $ — (2) $ 438.5 $ 440.1 (2) 2018 Revolver — — (2) 800.0 800.0 (2) Senior unsecured floating rate notes due 2021 299.6 283.3 (1) 299.1 298.4 (1) Senior unsecured notes due 2023 298.7 267.0 (1) 298.3 307.2 (1) Senior secured notes due 2026 298.0 279.9 (1) 297.8 305.6 (1) Senior unsecured notes due 2028 694.5 575.3 (1) 694.1 734.4 (1) Senior secured notes due 2025 (Second Lien 2025 Notes) 1,183.4 1,204.2 (1) $ — $ — Total $ 2,774.2 $ 2,609.7 $ 2,827.8 $ 2,885.7 (1) Level 1 Fair Value hierarchy

Derivative and Hedging Activiti

Derivative and Hedging Activities	9 Months Ended
	Oct. 01, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative and Hedging Activities	Derivative and Hedging Activities The Company has traditionally entered into interest rate swap agreements to reduce its exposure to the variable rate portion of its long-term debt. The Company also considers counterparty credit risk and its own credit risk in its determination of all estimated fair values. The Company has historically entered into derivative instruments covered by master netting arrangements whereby, in the event of a default as defined by the 2018 Credit Agreement (as defined below) or termination event, the non-defaulting party has the right to offset any amounts payable against any obligation of the defaulting party under the same counterparty agreement. See Note 15, Debt , for more information. Derivatives Not Accounted for as Hedges Interest Rate Swaps On March 15, 2017, the Company entered into an interest rate swap agreement, with an effective date of March 31, 2017. The swap has a notional value of $250.0 and fixed the variable portion of the Company’s floating rate debt at 1.815%. The swap expired in March 2020. Derivatives Accounted for as Hedges Cash Flow Hedges During the third quarter of 2019, the Company entered into two interest rate swap agreements with a combined notional value of $450.0. As of October 1, 2020, the Company has one swap agreement with a notional value of $150.0. These derivatives have been designated as cash flow hedges by the Company. The fair value of these hedges was a liability of $1.7 as of October 1, 2020, which is recorded in the other current liabilities line item on the Condensed Consolidated Balance Sheet. Changes in the fair value of cash flow hedges are recorded in Accumulated Other Comprehensive Income ("AOCI") and recorded in earnings in the period in which the hedged transaction occurs. The loss recognized in AOCI was $0.0 and $14.2 for the three and nine months ended October 1, 2020, respectively. For the three and nine months ended October 1, 2020 a loss of $1.6 and $3.0 was reclassified from AOCI to earnings, and included in the interest expense line item on the Condensed Consolidated Statements of Operations, and in operating activities on the Condensed Consolidated Statements of Cash Fl ows. For the three and nine months ended October 1, 2020 a loss of $10.4 was reclassified from AOCI to earnings resulting from the termination of a swap agreement, and included in the other income line item on the Condensed Consolidated Statements of Operations, and in operating activities on the Condensed Consolidated Statement of Cash Flows. Within the next 12 months,

Pension and Other Post-Retireme

Pension and Other Post-Retirement Benefits Defined Benefit Plan (Notes)	9 Months Ended
	Oct. 01, 2020
Retirement Benefits [Abstract]
Retirement Benefits [Text Block]	Pension and Other Post-Retirement Benefits Defined Benefit Plans For the Three Months Ended For the Nine Components of Net Periodic Pension Expense/(Income) October 1, September 26, October 1, September 26, Service cost $ 0.2 $ 0.3 $ 0.7 $ 1.0 Interest cost 5.4 10.0 20.1 30.0 Expected return on plan assets (16.6) (16.6) (49.5) (50.0) Amortization of net loss — 0.1 0.2 0.5 Curtailment loss (gain) (2) — — 33.9 (0.1) Settlement loss (3) 4.2 — 9.3 — Special termination benefits (1) (1.6) (5.5) 31.4 9.7 Net periodic pension expense (income) $ (8.4) $ (11.7) $ 46.1 $ (8.9) Other Benefits For the Three For the Nine Components of Other Benefit Expense October 1, September 26, October 1, September 26, Service cost $ 0.1 $ 0.2 $ 0.5 $ 0.7 Interest cost 0.2 0.3 0.7 1.0 Amortization of prior service cost (0.2) (0.2) (0.6) (0.7) Amortization of net gain (0.4) (0.6) (1.3) (1.8) Curtailment (gain) loss (2) — — (0.2) — Special termination benefits (1) $ — $ — $ 12.0 $ — Net periodic other benefit expense (income) $ (0.3) $ (0.3) $ 11.1 $ (0.8) (1) Special termination benefits for the three and nine months ending October 1, 2020 is a combination of pension value plan and postretirement medical plan changes offset by a reduction in the Company's net benefit obligation. For the three months and nine months ending October 1, 2020 special termination benefits, curtailment accounting, and the remeasurement of the pension assets and obligations resulted in a $(31.9) and $0.4 impact to OCI, respectively. For the three months and nine months ending October 1, 2020, retiree medical resulted in a $0.0 and $2.3 impact to OCI, respectively. This impact is included in the Company’s Condensed Consolidated Statements of Comprehensive (Loss) Income. The Company expects to record additional charges related to settlement accounting in subsequent 2020 quarters tied to cash payments made. (2) The Company's Voluntary Retirement Program ("VRP") resulted in an estimated 16% and 12% reduction in future working lifetime for the pension value plan and postretirement medical plan resulting in a curtailment accounting charge of $0.0 and $33.7 for the three and nine months ended October 1, 2020, respectively and is included in other (expense) income in the Company's Condensed Consolidated Statements of Operations. (3) Under ASC 715 - Compensation Retirement Benefits , settlement accounting is triggered when the total lump sums paid during the fiscal year exceed the combined service cost and interest cost component. Because the lump sums paid to date as part of the VRP exceed the estimated service cost and interest cost, the Company recognized a settlement loss of $4.2 and $9.3 for the three months and nine months ended October 1, 2020, respectively. The weighted average discount rate for the pension benefit obligation, as a result of remeasurement triggered by settlement accounting, changed to 2.52%. The components of net periodic pension expense (income) and other benefit expense, other than the service cost component, are included in other (expense) income in the Company's Condensed Consolidated Statements of Operations. Employer Contributions

Stock Compensation

Stock Compensation	9 Months Ended
	Oct. 01, 2020
Share-based Payment Arrangement, Noncash Expense [Abstract]
Stock Compensation	Stock Compensation Holdings has established the stockholder-approved 2014 Omnibus Incentive Plan, as amended (the “Omnibus Plan”), to grant cash and equity awards of Class A Common Stock, par value $0.01 per share (the “Common Stock”), to certain individuals. The Company recognized a net total of $6.2 and $7.5 of stock compensation expense for the three months ended October 1, 2020 and September 26, 2019, respectively, and a net total of $17.1 and $22.6 of stock compensation expense for the nine months ended October 1, 2020 and September 26, 2019, respectively. Holdings has established the Long-Term Incentive Plan (the “LTIP”) under the Omnibus Plan to grant equity awards to certain employees of the Company. Generally, specified employees are entitled to receive a long-term incentive award that, for the 2020 year, consisted of the following: • 60% of the award consisted of time-based, service-condition restricted Common Stock that vests in equal installments over a three-year period (the “RS Award”). Values for these awards are based on the value of Common Stock on the grant date; • 20% of the award consisted of performance-based, market-condition restricted Common Stock that vests on the three-year anniversary of the grant date contingent upon TSR compared to the Company’s peers (the “TSR Award”). Values for these awards are initially measured on the grant date using estimated payout levels derived from a Monte Carlo valuation model; and • 20% of the award consisted of performance-based (performance-condition) restricted Common Stock that vests on the three-year anniversary of the grant date contingent upon the Company’s cumulative three-year free cash flow as a percentage of the Company’s cumulative three-year revenues meeting certain pre-established goals (the “FCF Percentage Award”). Values for these awards are based on the dividend adjusted value of Common Stock on the grant date. During the nine months ended October 1, 2020, 499,945 shares, 198,980 shares, and 176,815 shares of Common Stock with aggregate grant date fair values of $20.6, $6.2 and $9.3 were granted as RS Awards, TSR Awards, and FCF Percentage Awards under the Company’s LTIP. During the nine months ended October 1, 2020, 38,249 shares of Common Stock with aggregate grant date fair values of $2.5 were granted and vested as a result of a union ratification bonus. The Board of Directors were granted 64,750 shares of Common Stock with an aggregate grant date value of $1.3 and vested 12,877 shares of Common Stock with an aggregate grant date value of $1.1 for the nine months ended October 1, 2020. Additionally, 489,889 shares of Common Stock with an aggregate grant date fair value of $33.2 under the LTIP vested during the nine months ended October 1, 2020.

Income Taxes (Notes)

Income Taxes (Notes)	9 Months Ended
	Oct. 01, 2020
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Income Taxes The process for calculating the Company’s income tax expense involves estimating actual current taxes due plus assessing temporary differences arising from differing treatment for tax and accounting purposes that are recorded as deferred tax assets and liabilities. Deferred tax assets are periodically evaluated to determine their recoverability. We have reviewed our material deferred tax assets to determine whether or not a valuation allowance was necessary. Based on the Company’s earnings history, in conjunction with other positive and negative evidence, we have determined it is more likely than not that the benefits from the deferred tax assets will be realized and therefore, a valuation allowance is not appropriate at this time. We will continue to regularly assess the potential for realization of our net deferred tax assets in future periods. Changes in future earnings projections, among other factors, may cause us to record a valuation allowance against some or all of our net deferred tax assets, which may materially impact our income tax expense in the period we determine that these factors have changed. The total net deferred tax asset at October 1, 2020, and December 31, 2019, was $126.7 and $98.2, respectively. The difference is primarily due to the creation of deductible temporary differences and utilization of taxable temporary differences within the current year. The Company files income tax returns in all jurisdictions in which it operates. The Company establishes reserves to provide for additional income taxes that may be due upon audit. These reserves are established based on management’s assessment as to the potential exposure attributable to permanent tax adjustments and associated interest. All tax reserves are analyzed quarterly and adjustments made as events occur that warrant modification. In general, the Company records income tax expense each quarter based on its estimate as to the full year’s effective tax rate. Certain items, however, are given discrete period treatment and the tax effects for such items are therefore reported in the quarter that an event arises. Events or items that may give rise to discrete recognition include excess tax benefits with respect to share-based compensation, finalizing amounts in income tax returns filed, finalizing audit examinations for open tax years and expiration of statutes of limitations, and changes in tax law. The 37.3% effective tax rate for the nine months ended October 1, 2020 differs from the 21.2% effective tax rate for the same period of 2019 primarily due to the benefit generated related to the carryback of our 2020 estimated income tax loss as permitted by the CARES Act and the benefit related to the re-measurement of deferred taxes due to the CARES Act resulting in increases to the tax rate. Additionally, the benefit generated by state tax credits and foreign rate differences resulted in net increases to the tax rate. As the Company is currently reporting a pre-tax loss for the nine months ended October 1, 2020, increases to tax expense result in a decrease to the effective tax rate and decreases to tax expense result in an increase to the effective tax rate. As of October 1, 2020, the Company has deferred $21.4 of employer payroll taxes, as allowed by the CARES Act, of which 50% are required to be deposited by December 2021 and the remaining 50% by December 2022. As of October 1, 2020, the Company has estimated it will be eligible for a pre-tax employee retention credit of approximately $13.6. The Company will continue to evaluate its eligibility for this credit for the remainder of 2020. In addition, as of October 1, 2020, the Company has recorded a deferral of $29.4 of VAT payments with the option to pay in smaller payments through the end of March 31, 2022 interest free under the United Kingdom deferral scheme. The CARES Act allows net operating losses to be carried back to the previous five years, when the federal tax rate was 35%. As of October 1, 2020 the Company anticipates it will report a net operating loss when it files its fiscal year 2020 tax return. Management will continue to monitor potential legislation as well as market conditions which may materially alter the anticipated value of this net operating loss. The Company's federal audit is substantially complete under the Compliance Assurance Program ("CAP") for the 2019 tax year. The Company will continue to participate in the CAP program for the 2020 tax year. The CAP program’s objective is to resolve issues in a timely, contemporaneous manner and eliminate the need for a lengthy post-filing examination. There are no open audits in the Company’s foreign jurisdictions.

Equity

Equity	9 Months Ended
	Oct. 01, 2020
Stockholders' Equity Note [Abstract]
Equity	Equity Earnings per Share Calculation Basic net income per share is computed using the weighted-average number of outstanding shares of Common Stock during the measurement period. Diluted net income per share is computed using the weighted-average number of outstanding shares of Common Stock and, when dilutive, potential outstanding shares of Common Stock during the measurement period. The Company accounts for treasury stock under the cost method and includes treasury stock as a component of stockholders’ equity. As of October 1, 2020, no treasury shares have been reissued or retired. The total authorization amount remaining under the current share repurchase program is approximately $925.0. During the nine month period ended October 1, 2020, the Company repurchased zero shares of its Common Stock under this share repurchase program. Share repurchases are currently on hold pending the outcome of the B737 MAX grounding and the COVID-19 pandemic. The Credit Agreement imposes restrictions on the Company’s ability to repurchase shares. The following table sets forth the computation of basic and diluted earnings per share: For the Three Months Ended October 1, 2020 September 26, 2019 Income Shares Per Share Income Shares Per Share Basic EPS (Loss) income available to common stockholders $ (155.5) 103.9 $ (1.50) $ 131.2 103.5 $ 1.27 Income allocated to participating securities — — 0.1 0.1 Net (loss) income $ (155.5) $ 131.3 Diluted potential common shares 1.0 Diluted EPS Net (loss) income $ (155.5) 103.9 $ (1.50) $ 131.3 104.6 $ 1.26 For the Nine Months Ended October 1, 2020 September 26, 2019 Income Shares Per Share Income Shares Per Share Basic EPS (Loss) income available to common stockholders $ (574.4) 103.8 $ (5.53) $ 462.1 103.6 $ 4.46 Income allocated to participating securities — — 0.3 0.1 Net (loss) income $ (574.4) $ 462.4 Diluted potential common shares 1.1 Diluted EPS Net (loss) income $ (574.4) 103.8 $ (5.53) $ 462.4 104.8 $ 4.41 Included in the outstanding Common Stock were 1.6 and 1.4 of issued but unvested shares at October 1, 2020 and September 26, 2019, respectively, which are excluded from the basic EPS calculation. Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Loss is summarized by component as follows: As of As of October 1, 2020 December 31, 2019 Pension $ (52.8) $ (53.1) Interest swaps (1.2) (0.6) SERP/Retiree medical 13.7 17.1 Foreign currency impact on long term intercompany loan (14.3) (13.1) Currency translation adjustment (75.0) (59.5) Total accumulated other comprehensive loss $ (129.6) $ (109.2) Amortization or curtailment cost recognition of the pension plans’ net gain/(loss) reclassified from accumulated other comprehensive loss and realized into costs of sales and selling, general and administrative on the Consolidated Statements of Operations was $0.7 and $0.7 for the three months ended October 1, 2020 and September 26, 2019, respectively, and $2.0 and $2.0 for the nine months ended October 1, 2020 and September 26, 2019, respectively. Rights Plan On April 22, 2020, the Company’s Board of Directors declared a dividend of one right (a “Right”) for each outstanding share of Common Stock held of record at the close of business on May 1, 2020 (the “Record Time”), and adopted a stockholder rights plan, as set forth in the Stockholder Protection Rights Agreement, dated as of April 22, 2020 (the “Rights Agreement”), between the Company and Computershare Inc., as Rights Agent. Generally, the Rights may cause substantial dilution to a person or group that acquires 10% (or 20% in the case of a passive institutional investor) or more of the Common Stock unless the Rights are first redeemed or the Rights Agreement is terminated by the Board. While the Rights will not prevent a takeover of the Company, they may discourage a merger, tender or exchange offer or other business combination involving the Company that is not approved by the Board. Nevertheless, the Rights will not interfere with a Board-approved transaction that is in the best interests of the Company and its stockholders because the Rights can be redeemed, or the Rights Agreement terminated, on or prior to the consummation of such a transaction. Prior to exercise, the Rights do not confer voting or dividend rights.

Commitments, Contingencies and

Commitments, Contingencies and Guarantees	9 Months Ended
	Oct. 01, 2020
Commitments Contingencies And Guarantees [Abstract]
Commitments, Contingencies and Guarantees	Commitments, Contingencies and Guarantees Litigation From time to time, the Company is subject to, and is presently involved in, litigation, legal proceedings, or other claims arising in the ordinary course of business. While the final outcome of these matters cannot be predicted with certainty, considering, among other things, the meritorious legal defenses available, the Company believes that, on a basis of information presently available, none of these items, when finally resolved, will have a material adverse effect on the Company’s long-term financial position or liquidity. On February 10, 2020, February 24, 2020, and March 24, 2020, three separate private securities class action lawsuits were filed against the Company in the U.S. District Court for the Northern District of Oklahoma, its Chief Executive Officer, Tom Gentile III, former chief financial officer, Jose Garcia, and former controller (principal accounting officer), John Gilson. On April 20, 2020, the Class Actions were consolidated by the court (the “Consolidated Class Action”), and on July 20, 2020, the plaintiffs filed a Consolidated Class Action Complaint which added Shawn Campbell, the Company’s former Vice President for the 737NG and 737 Max program, as a defendant. Allegations in the Consolidated Class Action include (i) violations of Section 10(b) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) and Rule 10b-5 promulgated thereunder against the Company and Messrs. Gentile, Garcia and Gilson, (ii) violations of Section 20(a) of the Exchange Act against the individual defendants, and (iii) violations of Section 10(b) of the Exchange Act and Rule 10b-5(a) and (c) promulgated thereunder against all defendants. On June 11, 2020, a shareholder derivative lawsuit (the “Derivative Action 1”) was filed against the Company (as nominal defendant), all members of the Company’s Board of Directors, and Messrs. Garcia and Gilson in the U.S. District Court for the Northern District of Oklahoma. Allegations in the Derivative Action 1 include (i) breach of fiduciary duty, (ii) abuse of control, and (iii) gross mismanagement. On October 5, 2020, a shareholder derivative lawsuit (the “Derivative Action 2” and, together with Derivative Action 1, the “Derivative Actions”) was filed against the Company (as nominal defendant), all members of the Company’s Board of Directors, and Messrs. Garcia and Gilson in the Eighteenth Judicial District, District Court of Sedgwick County, Kansas. Allegations in the Derivative Action 2 include (i) breach of fiduciary duty, (ii) waste of corporate assets, and (iii) unjust enrichment. The facts underlying the Consolidated Class Action and Derivative Actions relate to the accounting process compliance independent review (the “Accounting Review”) discussed in the Company’s January 30, 2020 press release and described under Management's Discussion and Analysis of Financial Condition and Results of Operations - Accounting Review of the 2019 Form 10-K and its resulting conclusions. The Company voluntarily reported to the SEC the determination that, with respect to the third quarter of 2019, the Company did not comply with its established accounting processes related to potential third quarter contingent liabilities received after the quarter-end. On March 24, 2020, the Staff of the SEC Enforcement Division informed the Company that it had determined to close its inquiry without recommending any enforcement action against Spirit. In addition, the facts underlying the Consolidated Class Action and Derivative Actions relate to the Company’s disclosures regarding the B737 MAX grounding and Spirit’s production rate (and related matters) after the grounding. The Company and individual defendants deny the allegations in the Consolidated Class Action and the Derivative Actions. From time to time, in the ordinary course of business and similar to others in the industry, the Company receives requests for information from government agencies in connection with their regulatory or investigational authority. Such requests can include subpoenas or demand letters for documents to assist the government in audits or investigations. The Company reviews such requests and notices and takes appropriate action. Additionally, the Company is subject to federal and state requirements for protection of the environment, including those for disposal of hazardous waste and remediation of contaminated sites. As a result, the Company is required to participate in certain government investigations regarding environmental remediation actions. The Company is involved in a lawsuit filed by a former executive officer for benefits withheld in connection with a disputed violation of restrictive covenants within his retirement agreement. While the Company believes it is not probable that the former executive will succeed in the lawsuit, based upon the executive’s selection of cash as the sole remedy in the third quarter of 2020, the lawsuit could result in a loss up to $40 including pre-trial interest and any other relief, including an estimated offset by retaining previously vested shares. Factors underlying this estimated range of loss may change from time to time, and actual results may vary significantly from this estimate. Customer and Vendor Claims From time to time the Company receives, or is subject to, customer and vendor claims arising in the ordinary course of business, including, but not limited to, those related to product quality and late delivery. The Company accrues for matters when losses are deemed probable and reasonably estimable. In evaluating matters for accrual and disclosure purposes, we take into consideration multiple factors including without limitation our historical experience with matters of a similar nature, the specific facts and circumstances asserted, the likelihood of an unfavorable outcome, and the severity of any potential loss. Any accruals deemed necessary are reevaluated at least quarterly and updated as matters progress over time. While the final outcome of these types of matters cannot be predicted with certainty, considering, among other things, the factual and legal defenses available, it is the opinion of the Company that, when finally resolved, no current claims will have a material adverse effect on the Company’s long-term financial position or liquidity. However, it is possible that the Company’s results of operations in a period could be materially affected by one or more of these other matters. Guarantees Outstanding guarantees were $19.4 and $21.5 at October 1, 2020 and December 31, 2019, respectively. Restricted Cash - Collateral Requirements The Company was required to maintain $19.5 and $16.4 of restricted cash as of October 1, 2020 and December 31, 2019, respectively, related to certain collateral requirements for obligations under its workers’ compensation programs. The restricted cash is included in “Other assets” in the Company’s Condensed Consolidated Balance Sheets. Indemnification The Company has entered into customary indemnification agreements with its non-employee directors, and its bylaws and certain executive employment agreements include indemnification and advancement provisions. Pursuant to the terms of the bylaws and, with respect to Jose Garcia, his employment agreement, the Company is providing Messrs. Garcia and Gilson advancement of defense costs and provisional indemnity with respect to the Consolidated Class Action and Derivative Actions. Under the bylaws and any applicable agreements, the Company agrees to indemnify each of these individuals against claims arising out of events or occurrences related to that individual’s service as the Company’s agent or the agent of any of its subsidiaries to the fullest extent legally permitted. The Company has agreed to indemnify parties for specified liabilities incurred, or that may be incurred, in connection with transactions they have entered into with the Company. The Company is unable to assess the potential number of future claims that may be asserted under these indemnities, nor the amounts thereof (if any). As a result, the Company cannot estimate the maximum potential amount of future payments under these indemnities and therefore, no liability has been recorded. Service and Product Warranties and Extraordinary Rework Provisions for estimated expenses related to service and product warranties and certain extraordinary rework are evaluated on a quarterly basis. These costs are accrued and are recorded to unallocated cost of goods sold. These estimates are established using historical information on the nature, frequency, and average cost of warranty claims, including the experience of industry peers. In the case of new development products or new customers, Spirit considers other factors including the experience of other entities in the same business and management judgment, among others. Service warranty and extraordinary rework is reported in current liabilities and other liabilities on the balance sheet. The warranty balance presented in the table below includes unresolved warranty claims that are in dispute in regards to their value as well as their contractual liability. The Company estimated the total costs related to some of these claims, however, there is significant uncertainty surrounding the disposition of these disputed claims and as such, the ultimate determination of the provision’s adequacy requires significant management judgment. The amount of the specific provisions recorded against disputed warranty claims was $8.1 as of October 1, 2020 and December 31, 2019. These specific provisions represent the Company’s best estimate of probable warranty claims. Should the Company incur higher than expected warranty costs and/or discover new or additional information related to these warranty provisions, the Company may incur additional charges that exceed these recorded provisions. The Company utilized available information to make appropriate assessments, however, the Company recognizes that data on actual claims experience is of limited duration and therefore, claims projections are subject to significant judgment. The amount of the reasonably possible disputed warranty claims in excess of the specific warranty provision was $12.1 as of October 1, 2020 and December 31, 2019. The following is a roll forward of the service warranty and extraordinary rework balance at October 1, 2020: Balance, December 31, 2019 $ 64.7 Charges to costs and expenses 2.9 Payouts (1.4) Exchange rate (0.2) Balance, October 1, 2020 $ 66.0

Other Income (Expense), Net

Other Income (Expense), Net	9 Months Ended
	Oct. 01, 2020
Other Nonoperating Income (Expense) [Abstract]
Other Income (Expense), Net	Other (Expense) Income, Net Other (expense) income, net is summarized as follows: For the Three For the Nine October 1, September 26, October 1, September 26, Kansas Development Finance Authority bond $ 0.6 $ 0.8 $ 2.3 $ 2.8 Rental and miscellaneous income — — 0.1 0.1 Interest income 0.9 2.6 9.0 8.8 Foreign currency (losses) gains (1) (3.4) (17.9) 1.4 (9.9) Loss on foreign currency contract and interest rate swaps (10.6) (0.5) (10.5) (18.3) Litigation settlement — — — 13.5 Loss on sale of accounts receivable (2.0) (6.5) (6.7) (18.7) Pension (loss) income (2) 9.0 12.0 (56.4) 9.8 ASC 326 credit loss reserve (3.6) — (3.6) — Other (0.9) — (1.0) — Total $ (10.0) $ (9.5) $ (65.4) $ (11.9)

Segment Information

Segment Information	9 Months Ended
	Oct. 01, 2020
Segment Reporting [Abstract]
Segment Information	Segment Information The Company operates in three principal segments: Fuselage Systems, Propulsion Systems, and Wing Systems. Revenue from Boeing represents a substantial portion of the Company's revenues in all segments. The Wing Systems Segment also includes significant revenues from Airbus. Approximately 81% of the Company's net revenues for the three months ended October 1, 2020 came from the Company's two largest customers, Boeing and Airbus. All other activities fall within the All Other segment, principally made up of non-recurring contracts, sundry sales of miscellaneous services, tooling contracts and sales of natural gas through a tenancy-in-common with other companies that have operations in Wichita, Kansas. The Company's primary profitability measure to review a segment’s operating performance is segment operating income before corporate selling, general and administrative expenses, research and development, and unallocated cost of sales. Corporate selling, general and administrative expenses include centralized functions such as accounting, treasury, and human resources that are not specifically related to the Company's operating segments and are not allocated in measuring the operating segments’ profitability and performance and net profit margins. Research and development includes research and development efforts that benefit the Company as a whole and are not unique to a specific segment. Restructuring costs represent corporate level charges related to involuntary workforce reductions and the VRP. Unallocated cost of sales includes general costs not directly attributable to segment operations, such as warranty, early retirement and other incentives. All of these items are not specifically related to the Company’s operating segments and are not utilized in measuring the operating segments’ profitability and performance. The Company’s Fuselage Systems Segment includes development, production, and marketing of forward, mid and rear fuselage sections and systems, primarily to aircraft Original Equipment Manufacturers (“OEMs”), as well as related spares and maintenance, repairs and overhaul (“MRO”) services and exterior components of rocket systems. The Fuselage Systems Segment manufactures products at the Company's facilities in Wichita, Kansas; Biddeford, Maine; Tulsa; Kinston, North Carolina; McAlester, Oklahoma; San Antonio, Texas; and Subang, Malaysia. The Fuselage Systems Segment also includes an assembly plant for the A350 XWB aircraft in Saint-Nazaire, France. The Company has previously announced site consolidation activities, including the McAlester, Oklahoma and San Antonio, Texas sites. The work transfer and closure activities for these sites will take place over the next several months. The Company’s Propulsion Systems Segment includes development, production and marketing of struts/pylons, nacelles (including thrust reversers), and related engine structural components primarily to aircraft or engine OEMs, as well as related spares and MRO services and internal components to rocket propulsion systems. The Propulsion Systems Segment manufactures products at the Company's facility in Wichita, Kansas; Biddeford, Maine; and San Antonio, Texas. The Company’s Wing Systems Segment includes development, production and marketing of wings and wing components (including flight control surfaces), and other miscellaneous structural parts primarily to aircraft OEMs, as well as related spares and MRO services. These activities take place at the Company’s facilities in Kinston, North Carolina; Tulsa and McAlester, Oklahoma; San Antonio, Texas; Prestwick, Scotland; and Subang, Malaysia. The Company has previously announced site consolidation activities, including the McAlester, Oklahoma and San Antonio, Texas sites. The work transfer and closure activities for these sites will take place over the next several months. The Company’s segments are consistent with the organization and responsibilities of management reporting to the chief operating decision-maker for the purpose of assessing performance. The Company’s definition of segment operating income differs from net profit margin as presented in its primary financial statements and a reconciliation of the segment and consolidated results is provided in the table set forth below. While some working capital accounts are maintained on a segment basis, much of the Company’s assets are not managed or maintained on a segment basis. Property, plant and equipment, including tooling, is used in the design and production of products for each of the segments and, therefore, is not allocated to any individual segment. In addition, cash, prepaid expenses, other assets and deferred taxes are managed and maintained on a consolidated basis and generally do not pertain to any particular segment. Raw materials and certain component parts are used in aerostructure production across all segments. Work-in-process inventory is identifiable by segment, but is managed and evaluated at the program level. As there is no segmentation of the Company’s productive assets, depreciation expense (included in fixed manufacturing costs and selling, general and administrative expenses) and capital expenditures, no allocation of these amounts has been made solely for purposes of segment disclosure requirements. The following table shows segment revenues and operating income for the three months and nine months ended October 1, 2020 and September 26, 2019: Three Months Ended Nine Months Ended October 1, September 26, October 1, September 26, Segment Revenues Fuselage Systems $ 421.1 $ 1,005.3 $ 1,299.7 $ 3,171.7 Propulsion Systems 170.8 520.9 565.6 1,525.5 Wing Systems 168.3 391.0 582.2 1,197.4 All Other 46.1 2.7 80.7 9.2 $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8 Segment Operating Income (Loss) Fuselage Systems (1) $ (96.7) $ 105.8 $ (434.6) $ 380.5 Propulsion Systems (2) (15.6) 111.7 (38.2) 304.9 Wing Systems (3) (23.2) 53.9 (52.1) 177.1 All Other 19.1 1.3 28.9 2.5 $ (116.4) $ 272.7 $ (496.0) $ 865.0 SG&A (52.8) (53.6) (179.2) (173.6) Research and development (7.5) (12.6) (28.1) (36.0) Unallocated cost of sales (0.2) (0.4) (8.1) 9.7 Total operating income $ (176.9) $ 206.1 $ (711.4) $ 665.1 (1) The three and nine months ended October 1, 2020 includes excess capacity production costs of $42.0 and $143.8, respectively, related to the temporary B737 MAX production schedule changes, abnormal costs of $(7.4) and $19.1, respectively, for temporary workforce adjustments as a result of COVID-19 production pause net of U.S. employee retention credit, $6.6 and $39.1, respectively, of restructuring costs, and $0 and $22.5, respectively, from loss on the disposition of assets. (2) The three and nine months ended October 1, 2020 includes excess capacity production costs of $17.5 and $50.8, respectively, related to the temporary B737 MAX production schedule changes, abnormal costs of $(2.9) and $7.3, respectively, for temporary workforce adjustments as a result of COVID-19 production paus e net of U.S employee retention credit , and $3.8 and $14.2, respectively, of restructuring costs. (3) The three and nine months ended October 1, 2020 includes excess capacity production costs of $13.1 and $34.2, respectively, related to the temporary B737 MAX and A320 production schedule changes, abnormal costs of $(0.6) and $7.4, respectively, for temporary workforce adjustments as a result of COVID-19, net of U.S employee retention credit and U.K government subsidies, $9.1 and $15.1, respectively, of restructuring costs, and $0 and $0.4, respectively, from loss on the disposition of assets.

Restructuring Charges (Notes)

Restructuring Charges (Notes)	9 Months Ended
	Oct. 01, 2020
Restructuring Costs [Abstract]
Restructuring and Related Activities Disclosure [Text Block]	23. Restructuring Costs In the nine month period ending October 1, 2020, the Company's customers, including Boeing and Airbus, have significantly reduced their overall production rates as a result of the COVID-19 pandemic and, in the case of Boeing, the B737 MAX grounding. As a result, the Company took actions to align costs to the updated production levels (restructuring activity). The Company’s planned restructuring activities are documented in a restructuring plan that is approved and controlled by management. The planned activities to align costs to expected production levels has materially affected the scope of operations and manner in which business is conducted by the Company. The restructuring plan includes additional restructuring activity in the three months ended October, 1, 2020, as the COVID-19 pandemic has continued to have a significant negative impact on the aviation industry and further impacted the Company’s global business. Restructuring costs under the plan, which are presented separately as a component of operating loss on the consolidated statement of operations, are related to involuntary workforce reductions and the VRP. The total restructuring costs of $68.4 for the nine months ended October 1, 2020 includes $47.5 related to involuntary workforce reductions and $20.9 related to the VRP. The total restructuring costs related to involuntary workforce reductions of $47.5 for the nine months ended October 1, 2020 that includes $31.5 for first quarter 2020 for approximately 3,200 employees, $4.9 for the second quarter 2020 for approximately 1,450 additional employees in response to COVID-19 impacts, and $11.1 for the third quarter 2020 for approximately 1,950 additional employees. The $47.5 total represents the full cost of the involuntary workforce restructuring activities included in the plan through October 1, 2020. Of the $47.5 total for the nine months ended October 1, 2020, $41.1 was paid during the nine-month period ended October 1, 2020 and the remaining $6.4 is recorded in the accrued expenses line item on the balance sheet as of October 1, 2020. The total restructuring costs related to the VRP of $20.9 for the nine months ended October 1, 2020 represents the total costs expected to be incurred for the voluntary retirement packages that includes $11.1 for the first quarter 2020 for 207 employees, $1.4 for the second quarter 2020 for 27 employees, $8.4 for the third quarter 2020 for 165 employees. The cost related to packages under the VRP are generally accrued and charged to earnings when the employee accepts the offer. Of the $20.9 total for the nine months ended October 1, 2020, $20.5 was paid during the nine-month period ended October 1, 2020 and the remaining $0.4 is recorded in the accrued expenses line item on the consolidated balance sheet as of October 1, 2020.

Acquisition (Notes)

Acquisition (Notes)	9 Months Ended
	Oct. 01, 2020
Business Combinations [Abstract]
Business Acquisition, Description of Acquired Entity	24. Acquisitions FMI On January 10, 2020, Spirit completed the acquisition of 100% of the outstanding equity of FMI. The acquisition-date fair value of consideration transferred was $121.6, which included cash payment to the seller, payment of closing indebtedness, and payment of selling expenses. Acquiring FMI aligns with the Company's strategic growth objectives to diversify its customer base and expand the current defense business. Founded in 1969 and headquartered in Biddeford, ME, FMI is an industry-leader in the design and manufacture of complex composite solutions that are primarily used in aerospace applications. Over the past 50 years, FMI has developed a portfolio related to its high temperature composites. FMI's main operations focus on multidirectional reinforced composites that enable high-temperature applications such as thermal protection systems, re-entry vehicle nose tips, and rocket motor throats and nozzles. Their unique capabilities have positioned them as a leader in 3D woven carbon-carbon high-temperature materials for hypersonic missiles, which the Department of Defense has identified as a national priority. The acquisition was funded from cash on hand. The Company incurred $1.5 in acquisition-related costs. Acquisition-related expenses were $0.0 and $0.5 for the three and nine months ended October 1, 2020, respectively, and are included in SG&A on the Condensed Consolidated Statement of Operations. The purchase price has been allocated among assets acquired and liabilities assumed at fair value, with the excess purchase price recorded as goodwill. The Company has recorded purchase accounting entries, which the Company concluded were final as of quarter ended October 1, 2020: At January 10, 2020 Cash and cash equivalents $ 3.5 Accounts receivable 5.3 Inventory 1.9 Contract Assets, short-term 5.6 Prepaid and other current assets 0.5 Equipment and leasehold improvements 12.3 Intangible assets 30.0 Goodwill 76.0 Other noncurrent assets 0.2 Total assets acquired $ 135.3 Accounts payable and accrued liabilities 1.8 Income Tax Payable 1.4 Contract liabilities, short-term 2.2 Accrued payroll and employee benefits 0.6 Other current liabilities 0.2 Deferred income taxes, non-current 7.5 Other noncurrent liabilities 0.2 Total liabilities assumed 13.9 Net assets acquired $ 121.4 The intangible assets included above consist of the following: Amount Amortization Period (in years) Developed technology asset $ 30.0 15 Total intangible assets $ 30.0 15 FMI has developed proprietary know-how over the past 50 years related to its densification and weaving processes. FMI's densification and weaving processes are used to develop specialized composites which can withstand high temperatures and meet the structural requirements set forth by FMI's customers. FMI has developed proprietary designs for 3D and 4D weaving of uncrimped carbon fibers. The densification process utilizes proprietary formulas of heat, pressure, materials, and time to create high density composite solutions at scale. FMI's developed technology results in high strength to weight composites with unmatched density, stability, and heat resistance, which are essential for the mission critical markets it serves. This developed technology is the primary driver of FMI's longstanding, competitive advantage in the markets. FMI is typically engaged with government agencies through purchase orders and does not have any life of program commitments from customers. As a result of FMI’s existing developed technology and incumbent position on previous purchase orders, FMI is positioned to capture future government programs. As such, the developed technology and contract assets were subsumed into one consolidated intangible asset (collectively referred to as the developed technology asset). The developed technology intangible asset is deemed to be the primary revenue-generating identifiable intangible asset acquired in the Transaction. The multi-period excess earnings method ("MPEEM") was used as the approach for estimating the fair value of the developed technology intangible asset which utilizes significant unobservable inputs, or Level 3 inputs, as defined by the fair value hierarchy. The principle behind this method is that the value of the intangible asset is equal to the present value of the after-tax cash flows attributable to the intangible asset only. The analysis included assumptions for projections of revenues and expenses, contributory asset charges, discount rates, and a tax impacts. The goodwill amount of $76.0 recognized is attributable primarily to expected revenue synergies generated by the integration of our products and technologies with those of FMI and intangible assets that do not qualify for separate recognition, such as the assembled workforce of FMI. None of the goodwill is expected to be deductible for income tax purposes. The goodwill is allocated $42.9 to the Fuselage Systems Segment and $33.1 to the Propulsion Systems Segment. This allocation was based upon the fair value of the projected earnings as of the acquisition date. The recognized goodwill was adjusted from $76.2 to $76.0 resulting from settlement of net working capital in second quarter of 2020. See Note 11, Other Assets, Goodwill, and Intangible Assets for more information on goodwill. The fair value of accounts receivables acquired is $5.3, which approximates the gross contractual amount. The Company expects substantially all amounts to be collectible. Prior to the acquisition, the Company did not have a preexisting relationship with FMI. The Company’s consolidated income statement from the acquisition date to the period ending October 1, 2020 includes revenue and earnings of FMI of $43.2 and $6.7, respectively. The following summary, prepared on a pro forma basis, presents the unaudited consolidated results of operations for the nine months ended October 1, 2020 and September 26, 2019, as if the acquisition of FMI had been completed as of the beginning of fiscal 2019, after including in fiscal 2019 any post-acquisition adjustments directly attributable to the acquisition, and after including the impact of adjustments such as amortization of intangible assets, and interest expense on related borrowings and, in each case, the related income tax effects. These amounts have been calculated after substantively applying the Company’s accounting policies. This pro forma presentation does not include any impact of transaction synergies. The pro forma results are not necessarily indicative of our results of operations had the Company owned FMI for the entire periods presented. For the Three Months Ended For the Nine Months Ended October 1, September 26, October 1, September 26, Revenue - as reported $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8 Revenue - pro forma 806.3 1,927.4 2,529.0 5,926.8 Net (loss) income - as reported $ (155.5) $ 131.3 $ (574.4) $ 462.4 Net (loss) income - pro forma (155.5) 131.9 (574.3) 464.1 Earnings Per Share - Diluted - as reported $ (1.50) 1.26 $ (5.53) 4.41 Earnings Per Share - Diluted - pro forma (1.50) 1.26 (5.53) 4.43 Asco On May 1, 2018, the Company and its wholly-owned subsidiary Spirit AeroSystems Belgium Holdings BVBA (“Spirit Belgium”) entered into a definitive agreement (as amended, the “Asco Purchase Agreement”) with certain private sellers providing for the purchase by Spirit Belgium of all of the issued and outstanding equity of S.R.I.F. N.V., the parent company of Asco Industries N.V. (“Asco”), subject to certain customary closing adjustments, including foreign currency adjustments (the “Asco Acquisition”). On September 25, 2020, the Company, Spirit Belgium and the Sellers entered into an amendment to the Asco Purchase Agreement (the “Termination Agreement”) pursuant to which the parties agreed to terminate the Asco Purchase Agreement, including all schedules and annexes thereto (other than certain confidentiality agreements) (collectively with the Asco Purchase Agreement, the “Transaction Documents”), effective as of September 25, 2020. Under the Termination Agreement, the parties also agreed to release each other from any and all claims, rights of action, howsoever arising, of every kind and nature, in connection with, arising out of, based upon or related to, directly or indirectly, the Transaction Documents, including any breach, non-performance, action or failure to act under the Transaction Documents. Acquisition-related expenses were ($0.1) and $3.1 for the three months ended October 1, 2020 and September 26, 2019, respectively, and $17.3 and $8.4 for the nine month ended October 1, 2020 and September 26, 2019, respectively, and are included in selling, general and administrative costs on the condensed and consolidated statement of operations. Bombardier On October 31, 2019, Spirit and Spirit AeroSystems Global Holdings Limited (“Spirit UK”), wholly owned subsidiaries of the Company, entered into a definitive agreement (the “Bombardier Purchase Agreement”) with Bombardier Inc., Bombardier Aerospace UK Limited, Bombardier Finance Inc. and Bombardier Services Corporation (collectively, the “Bombardier Sellers”) pursuant to which, subject to the satisfaction or waiver of certain conditions, Spirit UK will acquire the outstanding equity of Short Brothers plc (“Shorts”) and Bombardier Aerospace North Africa SAS ("BANA"), and Spirit will acquire substantially all the assets of the maintenance, repair and overhaul business in Dallas, Texas (collectively, the “Bombardier Acquired Business”) and assume certain liabilities of Shorts and BANA (the “Bombardier Acquisition”). Spirit, Spirit UK and the Bombardier Sellers entered into an amendment to the Bombardier Purchase Agreement on October 26, 2020 and closed the Bombardier Acquisition on October 30, 2020, which is described further under Note 26, Subsequent Events.

Condensed Consolidating Financi

Condensed Consolidating Financial Information	9 Months Ended
	Oct. 01, 2020
Condensed Financial Information Disclosure [Abstract]
Condensed Consolidating Financial Information	Condensed Consolidating Financial Information The Floating Rate Notes, 2023 Notes, and 2028 Notes (collectively, the "Unsecured Notes") are fully and unconditionally guaranteed on a senior unsecured basis by Holdings. The 2026 Notes and First Lien 2025 Notes are fully and unconditionally guaranteed on a senior secured first lien basis by Holdings and Spirit NC. The Second Lien 2025 Notes are fully and unconditionally guaranteed on a senior secured second lien basis by Holdings and Spirit NC. Together, the Floating Rate Notes, 2023 Notes, Second Lien 2025 Notes, First Lien 2025 Notes, 2026 Notes, and 2028 Notes shall be referred to as the “Existing Notes.” The following condensed consolidating financial information, which has been prepared in accordance with the requirements for presentation of Rule 3-10(d) of Regulation S-X promulgated under the Securities Act, presents the condensed consolidating financial information separately for: (i) Holdings, as the parent guarantor of the Existing Notes, as further detailed in Note 15, Debt ; (ii) Spirit, as issuer of the Existing Notes; (iii) Spirit NC, as a guarantor of the 2026 Notes and First Lien 2025 Notes on a senior secured first lien basis and the Second Lien 2025 Notes on a senior secured second lien basis; (iv) The Company’s other subsidiaries (the “Non-Guarantor Subsidiaries”), on a combined basis; (v) Consolidating entries and eliminations representing adjustments to (a) eliminate intercompany transactions between or among Holdings, Spirit NC, and the Non-Guarantor Subsidiaries, (b) eliminate the investments in the Company’s subsidiaries, and (c) record consolidating entries; and (vi) Holdings and its subsidiaries on a consolidated basis. Condensed Consolidating Statements of Operations For the Three Months Ended October 1, 2020 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Revenue $ — $ 705.5 $ 56.7 $ 130.0 $ (85.9) $ 806.3 Operating costs and expenses Cost of sales — 812.0 54.7 122.6 (85.9) 903.4 Selling, general and administrative 3.3 43.8 0.7 5.0 — 52.8 Restructuring cost — 10.9 0.2 8.4 — 19.5 Research and development — 6.2 0.1 1.2 — 7.5 Loss on disposal of assets — — — — — — Total operating costs and expenses 3.3 872.9 55.7 137.2 (85.9) 983.2 Operating (loss) income (3.3) (167.4) 1.0 (7.2) — (176.9) Interest expense and financing fee amortization — (53.0) — (0.4) 0.4 (53.0) Other (expense) income, net — (6.2) (0.1) (3.3) (0.4) (10.0) (Loss) income before income taxes and equity in net (loss) income of affiliate and subsidiaries (3.3) (226.6) 0.9 (10.9) — (239.9) Income tax benefit (provision) 1.2 82.8 (0.2) 1.4 — 85.2 (Loss) income before equity in net (loss) income of affiliate and subsidiaries (2.1) (143.8) 0.7 (9.5) — (154.7) Equity in net (loss) income of affiliate — — — (0.8) — (0.8) Equity in net (loss) income of subsidiaries (153.4) (9.6) — — 163.0 — Net (loss) income (155.5) (153.4) 0.7 (10.3) 163.0 (155.5) Other comprehensive (loss) income 51.7 51.7 — 18.7 (70.4) 51.7 Comprehensive (loss) income $ (103.8) $ (101.7) $ 0.7 $ 8.4 $ 92.6 $ (103.8) Condensed Consolidating Statements of Operations For the Three Months Ended September 26, 2019 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Revenue $ — $ 1,747.5 96.4 $ 218.3 $ (142.3) $ 1,919.9 Operating costs and expenses Cost of sales — 1,511.6 93.3 185.0 (142.3) 1,647.6 Selling, general and administrative 2.6 46.4 0.7 3.9 — 53.6 Research and development — 11.0 0.2 1.4 — 12.6 Total operating costs and expenses 2.6 1,569.0 94.2 190.3 (142.3) 1,713.8 Operating income (loss) (2.6) 178.5 2.2 28.0 — 206.1 Interest expense and financing fee amortization — (23.6) — (0.9) 0.9 (23.6) Other income (expense), net — (12.1) — 3.5 (0.9) (9.5) Income (loss) before income taxes and equity in net income of affiliate and subsidiaries (2.6) 142.8 2.2 30.6 — 173.0 Income tax (provision) benefit 0.6 (36.9) (0.5) (4.9) — (41.7) Income (loss) before equity in net income of affiliate and subsidiaries (2.0) 105.9 1.7 25.7 — 131.3 Equity in net income of affiliate — — — — — — Equity in net income (loss) of subsidiaries 133.3 27.4 — — (160.7) — Net income 131.3 133.3 1.7 25.7 (160.7) 131.3 Other comprehensive income (loss) 21.5 21.5 — (13.9) (7.6) 21.5 Comprehensive income (loss) $ 152.8 $ 154.8 $ 1.7 $ 11.8 $ (168.3) $ 152.8 Condensed Consolidating Statements of Operations For the Nine Months Ended October 1, 2020 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Revenue $ — $ 2,182.2 $ 224.2 $ 456.0 $ (334.2) $ 2,528.2 Operating costs and expenses Cost of sales — 2,628.4 216.4 430.4 (334.2) 2,941.0 Selling, general and administrative 11.7 151.6 1.9 14.0 — 179.2 Restructuring cost — 58.1 0.5 9.8 — 68.4 Research and development — 24.9 0.3 2.9 — 28.1 Loss on disposal of assets — 19.2 3.7 — — 22.9 Total operating costs and expenses 11.7 2,882.2 222.8 457.1 (334.2) 3,239.6 Operating (loss) income (11.7) (700.0) 1.4 (1.1) — (711.4) Interest expense and financing fee amortization — (133.7) — (1.9) 1.8 (133.8) Other (expense) income, net — (65.0) (0.2) 1.6 (1.8) (65.4) (Loss) income before income taxes and equity in net (loss) income of affiliate and subsidiaries (11.7) (898.7) 1.2 (1.4) — (910.6) Income tax benefit (provision) 4.4 334.5 (0.3) 1.4 — 340.0 (Loss) income before equity in net (loss) income of affiliate and subsidiaries (7.3) (564.2) 0.9 — — (570.6) Equity in net (loss) income of affiliate — — — (3.8) — (3.8) Equity in net (loss) income of subsidiaries (567.1) (2.9) — — 570.0 — Net (loss) income (574.4) (567.1) 0.9 (3.8) 570.0 (574.4) Other comprehensive (loss) income (20.4) (20.4) — (16.8) 37.2 (20.4) Comprehensive (loss) income $ (594.8) $ (587.5) $ 0.9 $ (20.6) $ 607.2 $ (594.8) Condensed Consolidating Statements of Operations For the Nine Months Ended September 26, 2019 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Revenue $ — $ 5,346.5 342.3 $ 719.9 $ (504.9) $ 5,903.8 Operating costs and expenses Cost of sales — 4,592.5 331.6 609.9 (504.9) 5,029.1 Selling, general and administrative 9.6 149.5 2.3 12.2 — 173.6 Research and development — 31.3 0.8 3.9 — 36.0 Total operating costs and expenses 9.6 4,773.3 334.7 626.0 (504.9) 5,238.7 Operating income (loss) (9.6) 573.2 7.6 93.9 — 665.1 Interest expense and financing fee amortization — (65.9) — (3.0) 2.8 (66.1) Other (expense) income, net — (13.7) — 4.6 (2.8) (11.9) Income (loss) before income taxes and equity in net income of affiliate and subsidiaries (9.6) 493.6 7.6 95.5 — 587.1 Income tax (provision) benefit 2.2 (110.2) (1.8) (14.9) — (124.7) Income (loss) before equity in net income of affiliate and subsidiaries (7.4) 383.4 5.8 80.6 — 462.4 Equity in net income of affiliate — — — — — — Equity in net income of subsidiaries 469.8 86.4 — — (556.2) — Net income 462.4 469.8 5.8 80.6 (556.2) 462.4 Other comprehensive (loss) income 16.7 16.7 — (18.0) 1.3 16.7 Comprehensive income (loss) $ 479.1 $ 486.5 $ 5.8 $ 62.6 $ (554.9) $ 479.1 Condensed Consolidating Balance Sheet October 1, 2020 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Assets Cash and cash equivalents $ — $ 1,258.7 $ — $ 182.6 $ — $ 1,441.3 Restricted cash — 1.3 — — — 1.3 Accounts receivable, net — 517.9 66.1 182.4 (377.6) 388.8 Contract assets, short-term — 279.0 — 54.6 — 333.6 Inventory, net — 816.1 161.8 205.4 — 1,183.3 Other current assets — 251.9 — 7.7 — 259.6 Total current assets — 3,124.9 227.9 632.7 (377.6) 3,607.9 Property, plant and equipment, net — 1,683.6 273.8 190.0 — 2,147.4 Right of use assets — 37.3 7.0 0.1 — 44.4 Contract assets, long-term — 4.1 — — — 4.1 Pension assets, net — 378.9 — 25.3 — 404.2 Deferred income taxes — 136.6 — 0.1 — 136.7 Goodwill — 76.0 — 2.4 — 78.4 Intangible assets, net — 29.5 — — — 29.5 Investment in subsidiary 1,172.0 818.8 — — (1,990.8) — Other assets — 226.1 — 112.5 (186.8) 151.8 Total assets $ 1,172.0 $ 6,515.8 $ 508.7 $ 963.1 $ (2,555.2) $ 6,604.4 Liabilities Accounts payable $ — $ 503.5 $ 234.8 $ 122.7 $ (377.9) $ 483.1 Accrued expenses — 240.9 1.7 46.9 0.3 289.8 Profit sharing — 33.9 — 4.2 — 38.1 Current portion of long-term debt — 333.5 0.2 1.8 — 335.5 Operating lease liabilities, short-term — 4.9 0.6 — — 5.5 Advance payments, short-term — 20.1 — — — 20.1 Contract liabilities, short-term — 100.9 — — — 100.9 Forward loss provision, long-term — 163.4 — 6.5 — 169.9 Deferred revenue and other deferred credits, short-term — 15.4 — 0.3 — 15.7 Other current liabilities — 25.6 — 12.1 — 37.7 Total current liabilities — 1,442.1 237.3 194.5 (377.6) 1,496.3 Long-term debt — 2,650.2 0.6 94.4 (86.2) 2,659.0 Operating lease liabilities, long-term — 32.7 6.4 — — 39.1 Advance payments, long-term — 325.0 — — — 325.0 Pension/OPEB obligation — 47.0 — — — 47.0 Contract liabilities, long-term — 371.7 — — — 371.7 Forward loss provision, long-term — 303.8 — — — 303.8 Deferred grant income liability - non-current — 8.9 — 18.5 — 27.4 Deferred revenue and other deferred credits — 28.2 — 5.4 — 33.6 Deferred income taxes — — — 10.0 — 10.0 Other liabilities — 214.2 — 5.9 (100.6) 119.5 Total equity 1,172.0 1,092.0 264.4 634.4 (1,990.8) 1,172.0 Total liabilities and stockholders’ equity $ 1,172.0 $ 6,515.8 $ 508.7 $ 963.1 $ (2,555.2) $ 6,604.4 Condensed Consolidating Balance Sheet December 31, 2019 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Assets Cash and cash equivalents $ — $ 2,193.3 $ — $ 157.2 $ — $ 2,350.5 Restricted cash — 0.3 — — — 0.3 Accounts receivable, net — 565.4 50.5 250.7 (320.2) 546.4 Inventory, net — 786.8 136.8 195.2 — 1,118.8 Contract assets, short-term — 458.8 — 69.5 — 528.3 Other current assets — 93.5 — 5.2 — 98.7 Total current assets — 4,098.1 187.3 677.8 (320.2) 4,643.0 Property, plant and equipment, net — 1,773.0 306.3 192.4 — 2,271.7 Right of use assets — 41.2 7.5 0.2 — 48.9 Contract assets, long-term — 6.4 — — — 6.4 Pension assets, net — 424.2 — 24.9 — 449.1 Deferred income taxes — 106.3 — 0.2 — 106.5 Goodwill — — — 2.4 — 2.4 Intangible assets, net — 1.2 — — — 1.2 Investment in subsidiary 1,761.9 838.4 — — (2,600.3) — Other assets — 147.6 — 116.0 (186.8) 76.8 Total assets $ 1,761.9 $ 7,436.4 $ 501.1 $ 1,013.9 $ (3,107.3) $ 7,606.0 Liabilities Accounts payable $ — $ 977.1 $ 226.3 $ 175.1 $ (320.2) $ 1,058.3 Accrued expenses — 210.0 0.8 29.4 — 240.2 Profit sharing — 76.9 — 7.6 — 84.5 Current portion of long-term debt — 48.4 0.2 1.6 — 50.2 Operating lease liabilities, short-term — 5.3 0.6 0.1 — 6.0 Advance payments, short-term — 21.6 — — — 21.6 Contract liabilities, short-term — 158.3 — — — 158.3 Forward loss provision, long-term — 83.9 — — — 83.9 Deferred revenue and other deferred credits, short-term — 14.5 — 0.3 — 14.8 Other current liabilities — 29.3 2.1 11.5 — 42.9 Total current liabilities — 1,625.3 230.0 225.6 (320.2) 1,760.7 Long-term debt — 2,974.7 0.9 94.7 (86.2) 2,984.1 Operating lease liabilities, long-term — 36.0 6.9 0.1 — 43.0 Advance payments, long-term — 333.3 — — — 333.3 Pension/OPEB obligation — 35.7 — — — 35.7 Contract liabilities, long-term — 356.3 — — — 356.3 Forward loss provision, long-term — 163.5 — — — 163.5 Deferred grant income liability - non-current — 9.2 — 19.8 — 29.0 Deferred revenue and other deferred credits — 30.4 — 4.0 — 34.4 Deferred income taxes — — — 8.3 — 8.3 Other liabilities — 190.1 — 6.3 (100.6) 95.8 Total equity 1,761.9 1,681.9 263.3 655.1 (2,600.3) 1,761.9 Total liabilities and stockholders’ equity $ 1,761.9 $ 7,436.4 $ 501.1 $ 1,013.9 $ (3,107.3) $ 7,606.0 Condensed Consolidating Statements of Cash Flows For the Nine Months Ended October 1, 2020 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Operating activities Net cash used in operating activities $ — $ (634.9) $ (16.2) $ 38.3 $ — $ (612.8) Investing activities Purchase of property, plant and equipment — (53.4) (1.3) (15.7) — (70.4) Acquisition, net of cash acquired — (117.9) — — — (117.9) Other — 0.4 — 4.5 — 4.9 Net cash used in investing activities — (170.9) (1.3) (11.2) — (183.4) Financing activities Proceeds from issuance of debt — 1,200.0 — — — 1,200.0 Proceeds from revolving credit facility — — — — — — Customer financing — 10.0 — — — 10.0 Principal payments of debt — (21.2) (0.2) (1.3) — (22.7) Payments on term loans — (439.7) — — — (439.7) Payments on revolving credit facility — (800.0) — — — (800.0) Proceeds (payments) from intercompany debt — (20.9) 17.7 3.2 — — Taxes paid related to net share settlement of awards — (14.0) — — — (14.0) Proceeds (payments) from subsidiary for purchase of treasury stock (0.1) 0.1 — — — — Purchase of treasury stock 0.1 — — — — 0.1 Proceeds (payments) from subsidiary for dividends paid 14.4 (14.4) — — — — Dividends paid (14.4) — — — — (14.4) Proceeds from issuance of ESPP stock — 2.6 — — — 2.6 Debt issuance costs — (27.6) — — — (27.6) Other — — 0.1 — 0.1 Net cash (used in) provided by financing activities — (125.1) 17.5 2.0 — (105.6) Effect of exchange rate changes on cash and cash equivalents — 0.5 — (3.8) — (3.3) Net (decrease) increase in cash and cash equivalents for the period — (930.4) — 25.3 — (905.1) Cash, cash equivalents, and restricted cash, beginning of period — 2,210.0 — 157.2 — 2,367.2 Cash, cash equivalents, and restricted cash, end of period $ — $ 1,279.6 $ — $ 182.5 $ — $ 1,462.1 Condensed Consolidating Statements of Cash Flows For the Nine Months Ended September 26, 2019 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Operating activities Net cash provided by operating activities $ — $ 571.3 $ 53.3 $ 94.0 $ — $ 718.6 Investing activities Purchase of property, plant and equipment — (94.0) (7.7) (17.1) — (118.8) Other — 0.1 — — — 0.1 Net cash used in investing activities — (93.9) (7.7) (17.1) — (118.7) Financing activities Proceeds from issuance of debt — 250.0 — — — 250.0 Proceeds from revolving credit facility — 100.0 — — — 100.0 Principal payments of debt — (7.8) (0.2) (0.5) — (8.5) Payments on term loans — (5.2) — — — (5.2) Payments on revolving credit facility — (100.0) — — — (100.0) Proceeds (payments) from intercompany debt — 56.1 (45.4) (10.7) — — Taxes paid related to net share settlement of awards — (12.1) — — — (12.1) Proceeds (payments) from subsidiary for dividends paid 37.8 (37.6) — (0.2) — — Dividends paid (37.8) — — — — (37.8) Proceeds (payments) from subsidiary for purchase of treasury stock 75.0 (75.0) — — — — Purchase of treasury stock (75.0) — — — — (75.0) Proceeds from issuance of ESPP stock — 1.3 — — — 1.3 Other — 0.8 — — — 0.8 Net cash provided by (used in) financing activities — 170.5 (45.6) (11.4) — 113.5 Effect of exchange rate changes on cash and cash equivalents — (13.2) — (0.3) (13.5) Net increase in cash and cash equivalents for the period — 634.7 — 65.2 — 699.9 Cash, cash equivalents, and restricted cash, beginning of period — 725.5 — 68.6 — 794.1 Cash, cash equivalents, and restricted cash, end of period — 1,360.2 — 133.8 — 1,494.0

Subsequent Event (Notes)

Subsequent Event (Notes)	9 Months Ended
	Oct. 01, 2020
Subsequent Event [Line Items]
Subsequent Events [Text Block]	. Subsequent Events Refinancing On October 5, 2020, Spirit, the Company, and Spirit NC terminated the 2018 Credit Agreement, entered into the Credit Agreement, issued the First Lien 2025 Notes, and entered into the Fourth Supplemental Indenture with respect to the 2026 Notes. For more information, see Note 15, Debt. Bombardie r Acquisition On October 26, 2020, Spirit, Spirit UK and the Bombardier Sellers entered into an amendment to the Bombardier Purchase Agreement (the “Amendment”). The Amendment reduced the net proceeds purchase price payable to the Bombardier Sellers from $500 to $275. Spirit will continue to make a special contribution of £100 (approximately $130) to the Shorts pension scheme (“Shorts Pension”) on the first anniversary of closing. On October 30, 2020, Spirit and Spirit UK closed the Bombardier Acquisition and assumed certain liabilities including the net pension liabilities of the Shorts Pension and Shorts' financial payment obligations under a repayable investment agreement with the United Kingdom’s Department for Business, Energy and Industrial Strategy. The acquired business involves aerostructures and fabrication manufacturing and MRO services. The backlog of work includes long-term contracts on Airbus programs, along with Bombardier business jets. The acquisition is in line with the Company’s growth strategy of increasing Airbus content, growing the Company's aftermarket business, and developing a low-cost country footprint. The Company has begun the process of estimating the fair value of tangible and intangible assets acquired and liabilities assumed in connection with the Bombardier Acquisition. The initial fair value estimates and related purchase price allocation will be completed on a preliminary basis and recorded in the fourth quarter of 2020. We expect any supplemental pro forma information required by ASC 805 to be completed in the fourth quarter and disclosed in the Company’s 2020 Annual Report on Form 10-K. T he amount of time required to accurately calculate any required supplemental pro-forma financial data and compile the detailed information required to support the purchase accounting results exceeds the amount of time which has lapsed since closing the transaction on October 30, 2020. As a result, any supplemental pro-forma financial information required by ASC 805 is not available as of the filing date. Acquisition-related expenses were $3.3 and $6.2 for the three months and nine months ended October 1, 2020, respectively, and are included in selling, general and administrative costs on the condensed consolidated statement of operations.

New Accounting Pronouncements (

New Accounting Pronouncements (Policies)	9 Months Ended
	Oct. 01, 2020
Accounting Policies [Abstract]
New Accounting Pronouncements, Policy [Policy Text Block]	. New Accounting Pronouncements In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848) Facilitation of the Effects of Reference Rate Reform on Financial Reportin g (“ASU 2020-04”), which provides temporary optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. ASU 2020-04 provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. ASU 2020-04 is effective for all entities as of March 12, 2020 through December 31, 2022, and an entity may elect to apply ASU 2020-04 for contract modifications by Topic or Industry Subtopic as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively from a date within an interim period that includes or is subsequent to March 12, 2020, up to the date that the financial statements are available to be issued. An entity may elect to apply ASU 2020-04 to eligible hedging relationships existing as of the beginning of the interim period that includes March 12, 2020 and to new eligible hedging relationships entered into after the beginning of the interim period that includes March 12, 2020. The Company is currently evaluating the potential impact of adopting this guidance on our consolidated financial statements. In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes ("ASU 2019-12”) which modifies FASB Accounting Standards Codification 740 to simplify the accounting for income taxes. ASU 2019-12 is effective for fiscal years beginning after December 15, 2020, with early adoption permitted. The Company is currently evaluating the potential impact of adopting this guidance on our consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-14, Compensation-Retirement Benefits-Defined Benefit Plans-General (Topic 715-20): Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans

Accounts Receivable and Allow_2

Accounts Receivable and Allowance for Credit Losses Allowance for Credit Losses (Policies)	9 Months Ended
	Oct. 01, 2020
Credit Loss [Abstract]
Credit Loss, Financial Instrument [Text Block]	Allowance for Credit Losses Beginning January 1, 2020, management assesses and records an allowance for credit losses on financial assets within the scope of ASU 2016-13 using the CECL model. Prior periods allowance for credit losses were based on a review of outstanding receivables that are charged off against the allowance after the potential for recovery is considered remote in accordance with legacy GAAP. The amount necessary to adjust the allowance for credit losses to management’s current estimate, as of the reporting date, on these assets is recorded in net income as credit loss expense. All credit losses reported in accordance with ASU 2016-13 were on trade receivables and/or contract assets arising from the Company’s contracts with customers. In determining the appropriate methodology to use within the CECL model for receivables and contract assets arising from the Company’s contracts with customers, the Company considered the risk characteristics of the applicable assets. Spirit segregated the trade receivables and contract assets into “pools” of assets at the major customer level. The Company's assessment was based on similarity of risk characteristics shared by these pool of assets. Management observed that risks for collectability, with regard to the trade receivables and contract assets resulting from contracts with customers include: macro level economic conditions that impact all of Spirit’s customers, macro level market conditions that could impact Spirit’s customers in certain aircraft categories, certain customer specific market conditions, certain customer specific economic conditions, and certain customer specific administrative conditions. The Company selected a loss-rate method for the CECL model, based on the relationship between historical write-offs of receivables and the underlying sales by major customer. Utilizing this model, a historical loss-rate is applied against the amortized cost of applicable assets, at the time the asset is established. The loss rate reflects the Company’s current estimate of the risk of loss (even when that risk is remote) over the expected remaining contractual life of the assets. The Company's policy is to deduct write-offs from the allowance for credit losses account in the period in which the financial assets are deemed uncollectible.

Leases (Policies)

Leases (Policies)	9 Months Ended
	Oct. 01, 2020
Leases [Abstract]
Lessee, Leases [Policy Text Block]	The Company determines if an arrangement is a lease at the inception of a signed agreement. Operating leases are included in right-of-use (“ROU”) assets (long-term), short-term operating lease liabilities, and long-term operating lease liabilities on the Company’s consolidated balance sheet. Finance leases are included in Property, Plant and Equipment, current maturities of long-term debt, and long-term debt. ROU assets represent the right of the Company to use an underlying asset for the length of the lease term, and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and liabilities are recognized at the lease commencement date based on the estimated present value of lease payments over the lease term. To determine the present value of lease payments, the Company uses its estimated incremental borrowing rate or the implicit rate, if readily determinable. The estimated incremental borrowing rate is based on information available at the lease commencement date, including any recent debt issuances and publicly available data for instruments with similar characteristics. The ROU asset also includes any lease payments made and excludes lease incentives. The Company's lease terms may include options to extend or terminate the lease and, when it is reasonably certain that an option will be exercised, those options are included in the net present value calculation. Leases with a term of 12 months or less, which are primarily related to automobiles and manufacturing equipment, are not recorded on the balance sheet. The aggregate amount of lease cost for leases with a term of 12 months or less is not material.

Other Assets goodwill (Policies

Other Assets goodwill (Policies)	9 Months Ended
	Oct. 01, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets Disclosure [Text Block]	Goodwill is summarized as follows: October 1, December 31, Goodwill - United Kingdom 2.4 2.4 Goodwill - United States (1) 76.0 — Total $ 78.4 $ 2.4 (1) The acquisition of Fiber Materials Inc. ("FMI") on January 10, 2020 resulted in the establishment of $76.2 goodwill. In second quarter of 2020, $0.2 was received upon final settlement of net working capital, reducing the goodwill balance to $76.0. The balance of goodwill by reportable segment as of October 1, 2020 is allocated $42.9 to the Fuselage Systems Segment, $33.1 to the Propulsion Systems Segment, and $2.4 to the Wing Systems Segment. The total goodwill value of $78.4 includes no accumulated impairment loss in any of the periods presented. The change in value from December 31, 2019 to October 1, 2020 for the United Kingdom goodwill item, as seen in the table above, reflects net exchange differences arising during the period. The goodwill balance as of December 31, 2019 of $2.4 is allocated to the Wing Systems Segment. The Company assesses goodwill for impairment annually or more frequently if events or circumstances indicate that the fair value of a reporting unit that includes goodwill may be lower than its carrying value. F or the period ended October 1, 2020, there were no triggering events which would require the Company to update its goodwill impairment analysis. Each of the reportable segments, noted above, is comprised of a single operating segment, which is the reporting unit for goodwill. At October 1, 2020, the Fuselage Systems reporting unit has $42.9 of goodwill, the Propulsion Systems reporting unit has $33.1 of goodwill, and the Wing Systems reporting unit has $2.4 of goodwill . Intangible assets are summarized as follows: October 1, December 31, Intangible assets Patents $ 2.0 $ 2.0 Favorable leasehold interests 2.8 2.8 Developed technology asset (1) 30.0 — Total intangible assets 34.8 4.8 Less: Accumulated amortization - patents (2.0) (1.9) Accumulated amortization - favorable leasehold interest (1.8) (1.7) Accumulated amortization - developed technology asset (1.5) — Intangible assets, net 29.5 1.2 (1) The acquisition of FMI on January 10, 2020 resulted in the establishment of a $30.0 intangible asset for developed technology. The amortization for each of the five succeeding years relating to intangible assets currently recorded in the Condensed Consolidated Balance sheet and the weighted average amortization is estimated to be the following as of October 1, 2020: Year Patents Favorable leasehold interest Developed Technology Total remaining in 2020 — — 0.5 0.5 2021 — 0.1 2.0 2.1 2022 — 0.1 2.0 2.1 2023 — 0.1 2.0 2.1 2024 — 0.1 2.0 2.1 2025 — 0.1 2.0 2.1 Weighted average amortization period — 8.8 14.3 14.1

Changes in Estimates Changes in

Changes in Estimates Changes in Estimates (Tables)	9 Months Ended
	Oct. 01, 2020
Accounting Changes and Error Corrections [Abstract]
Schedule of Change in Accounting Estimate [Table Text Block]	Changes in estimates are summarized below: For the Three Months Ended For the Nine Months Ended Changes in Estimates October 1, 2020 September 26, 2019 October 1, 2020 September 26, 2019 (Unfavorable) Favorable Cumulative Catch-up Adjustment by Segment Fuselage $ 8.8 $ (14.4) $ (18.9) $ (2.0) Propulsion (4.6) 1.8 (8.6) (1.5) Wing 0.4 (0.4) (3.1) 1.7 Total (Unfavorable) Favorable Cumulative Catch-up Adjustment $ 4.6 $ (13.0) $ (30.6) $ (1.8) Changes in Estimates on Loss Programs (Forward Loss) by Segment Fuselage $ (92.0) $ (18.8) $ (260.3) $ (13.8) Propulsion (14.9) (4.0) (34.2) (3.1) Wing (21.5) (6.0) (47.7) (4.9) Total Changes in Estimates (Forward Loss) on Loss Programs $ (128.4) $ (28.8) $ (342.2) $ (21.8) Total Change in Estimate $ (123.8) $ (41.8) $ (372.8) $ (23.6) EPS Impact (diluted per share based upon 2020 forecasted effective tax rate) $ (0.77) $ (0.31) $ (2.33) $ (0.18)

Accounts Receivable, net (Table

Accounts Receivable, net (Tables)	9 Months Ended
	Oct. 01, 2020
Accounts Receivable, after Allowance for Credit Loss, Current [Abstract]
Accounts Receivable, Net	Accounts receivable, net consists of the following: October 1, December 31, Trade receivables $ 366.9 $ 515.2 Other 26.5 32.6 Less: allowance for doubtful accounts (4.6) (1.4) Accounts receivable, net $ 388.8 $ 546.4

Revenue (Tables)

Revenue (Tables) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 806.3	$ 1,919.9	$ 2,528.2	$ 5,903.8
Boeing [Member]
Disaggregation of Revenue [Line Items]
Revenues	493.8	1,542	1,539.9	4,705.1
Airbus [Member]
Disaggregation of Revenue [Line Items]
Revenues	160.1	284.1	575.3	934
Other Customer [Member]
Disaggregation of Revenue [Line Items]
Revenues	152.4	93.8	413	264.7
UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues	642	1,620.6	1,936.4	4,935.8
UNITED KINGDOM
Disaggregation of Revenue [Line Items]
Revenues	103.6	177.4	358.2	577.6
Other International [Member]
Disaggregation of Revenue [Line Items]
Revenues	60.7	121.9	233.6	390.4
Total International [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 164.3	$ 299.3	$ 591.8	$ 968

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Oct. 01, 2020
Inventory Disclosure [Abstract]
Summary Of Inventories	Work-in-process inventory includes direct labor, direct material, overhead, and purchases on contracts for which revenue is recognized at a point in time as well as sub-assembly parts that have not been issued to production on contracts for which revenue is recognized using the input method. For the periods ended October 1, 2020 and December 31, 2019, work-in-process inventory includes $184.9 and $157.2, respectively, of costs incurred in anticipation of specific contracts and no impairments were recorded in the period. Product inventory, summarized in the table above, is shown net of valuation reserves of $49.2 and $39.0 as of October 1, 2020 and December 31, 2019, respectively. Excess capacity and abnormal production costs are excluded from inventory and recognized as expense in the period incurred. Cost of sales for the three and nine month periods ended October 1, 2020 includes period expense of $72.6 and $228.8, respectively, of excess capacity production costs related to temporary B737 MAX and A320 production schedule changes. Cost of sales also includes abnormal costs related to temporary workforce adjustments as a result of COVID-19 production pause, net of the U.S. employee retention credit and U.K. government subsidies for the three and nine month periods ended October 1, 2020 of $(10.9) and $33.8, respectively.

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Oct. 01, 2020
Property, Plant and Equipment [Abstract]
Property, plant and equipment, net	Property, plant and equipment, net consists of the following: October 1, December 31, Land $ 17.6 $ 15.9 Buildings (including improvements) 937.2 924.0 Machinery and equipment 1,973.2 1,941.5 Tooling 1,025.9 1,047.4 Capitalized software 275.3 277.8 Construction-in-progress 196.1 192.8 Total 4,425.3 4,399.4 Less: accumulated depreciation (2,277.9) (2,127.7) Property, plant and equipment, net $ 2,147.4 $ 2,271.7

Other Assets (Tables)

Other Assets (Tables)	9 Months Ended
	Oct. 01, 2020
Other Assets, Noncurrent [Abstract]
Schedule of Other Assets	Other current assets are summarized as follows: October 1, December 31, Prepaid expenses 15.5 19.3 Income tax receivable 240.9 74.2 Other assets- short term 3.2 5.2 Total other current assets $ 259.6 $ 98.7 Other assets are summarized as follows: October 1, December 31, Deferred financing Deferred financing costs 48.3 41.7 Less: Accumulated amortization - deferred financing costs (42.2) (36.9) Deferred financing costs, net 6.1 4.8 Other Long term income tax receivable (1) 72.7 — Supply agreements (2) 11.2 11.5 Equity in net assets of affiliates 3.9 7.7 Restricted cash - collateral requirements 19.5 16.4 Other 38.4 36.4 Total other long term assets $ 151.8 $ 76.8 (1) Increase in income tax receivable not expected to be received within 12 months and is an increase over the prior year as a result of the carryback provisions included in the CARES Act. (2) Certain payments accounted for as consideration paid by the Company to a customer are being amortized as reductions to net revenues.

Other Assets Intangible Assets

Other Assets Intangible Assets (Tables)	9 Months Ended
	Oct. 01, 2020
Finite-Lived Intangible Assets [Line Items]
Schedule of Finite-Lived Intangible Assets [Table Text Block]	Intangible assets are summarized as follows: October 1, December 31, Intangible assets Patents $ 2.0 $ 2.0 Favorable leasehold interests 2.8 2.8 Developed technology asset (1) 30.0 — Total intangible assets 34.8 4.8 Less: Accumulated amortization - patents (2.0) (1.9) Accumulated amortization - favorable leasehold interest (1.8) (1.7) Accumulated amortization - developed technology asset (1.5) — Intangible assets, net 29.5 1.2
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	The amortization for each of the five succeeding years relating to intangible assets currently recorded in the Condensed Consolidated Balance sheet and the weighted average amortization is estimated to be the following as of October 1, 2020: Year Patents Favorable leasehold interest Developed Technology Total remaining in 2020 — — 0.5 0.5 2021 — 0.1 2.0 2.1 2022 — 0.1 2.0 2.1 2023 — 0.1 2.0 2.1 2024 — 0.1 2.0 2.1 2025 — 0.1 2.0 2.1 Weighted average amortization period — 8.8 14.3 14.1

Other Assets Goodwill (Tables)

Other Assets Goodwill (Tables)	9 Months Ended
	Oct. 01, 2020
Goodwill [Abstract]
Goodwill Disclosure [Text Block]	Goodwill is summarized as follows: October 1, December 31, Goodwill - United Kingdom 2.4 2.4 Goodwill - United States (1) 76.0 — Total $ 78.4 $ 2.4 (1) The acquisition of Fiber Materials Inc. ("FMI") on January 10, 2020 resulted in the establishment of $76.2 goodwill. In second quarter of 2020, $0.2 was received upon final settlement of net working capital, reducing the goodwill balance to $76.0. The balance of goodwill by reportable segment as of October 1, 2020 is allocated $42.9 to the Fuselage Systems Segment, $33.1 to the Propulsion Systems Segment, and $2.4 to the Wing Systems Segment. The total goodwill value of $78.4 includes no accumulated impairment loss in any of the periods presented. The change in value from December 31, 2019 to October 1, 2020 for the United Kingdom goodwill item, as seen in the table above, reflects net exchange differences arising during the period. The goodwill balance as of December 31, 2019 of $2.4 is allocated to the Wing Systems Segment. The Company assesses goodwill for impairment annually or more frequently if events or circumstances indicate that the fair value of a reporting unit that includes goodwill may be lower than its carrying value. F or the period ended October 1, 2020, there were no triggering events which would require the Company to update its goodwill impairment analysis. Each of the reportable segments, noted above, is comprised of a single operating segment, which is the reporting unit for goodwill. At October 1, 2020, the Fuselage Systems reporting unit has $42.9 of goodwill, the Propulsion Systems reporting unit has $33.1 of goodwill, and the Wing Systems reporting unit has $2.4 of goodwill

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Oct. 01, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	The guidance discloses three levels of inputs that may be used to measure fair value: Level 1 Quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 1 assets and liabilities include debt and equity securities and derivative contracts that are traded in an active exchange market. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 2 assets and liabilities include debt securities with quoted prices that are traded less frequently than exchange-traded instruments and derivative contracts whose value is determined using a pricing model with inputs that are observable in the market or can be derived principally from or corroborated by observable market data. Observable inputs, such as current and forward interest rates and foreign exchange rates, are used in determining the fair value of the interest rate swaps and foreign currency hedge contracts. Level 3 Unobservable inputs that are supported by little or no market activity and are significant to the fair value of assets and liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation.
Carrying Amount And Estimated Fair Value Of Long Term Debt	The following table presents the carrying amount and estimated fair value of long-term debt (table excludes First Lien 2025 Notes, which were issued after quarter end on October 5, 2020): October 1, 2020 December 31, 2019 Carrying Fair Carrying Fair 2018 Term Loan and 2018 DDTL (including current portion) $ — $ — (2) $ 438.5 $ 440.1 (2) 2018 Revolver — — (2) 800.0 800.0 (2) Senior unsecured floating rate notes due 2021 299.6 283.3 (1) 299.1 298.4 (1) Senior unsecured notes due 2023 298.7 267.0 (1) 298.3 307.2 (1) Senior secured notes due 2026 298.0 279.9 (1) 297.8 305.6 (1) Senior unsecured notes due 2028 694.5 575.3 (1) 694.1 734.4 (1) Senior secured notes due 2025 (Second Lien 2025 Notes) 1,183.4 1,204.2 (1) $ — $ — Total $ 2,774.2 $ 2,609.7 $ 2,827.8 $ 2,885.7 (1) Level 1 Fair Value hierarchy

Debt (Tables)

Debt (Tables)	9 Months Ended
	Oct. 01, 2020
Debt Disclosure [Abstract]
Long Term Debt And Capital Lease Obligations Current And Non Current	Total debt shown on the balance sheet is comprised of the following: October 1, 2020 December 31, 2019 Current Noncurrent Current Noncurrent 2018 Term Loan and 2018 DDTL $ — $ — $ 22.8 $ 415.7 2018 Revolver — — — 800.0 Senior unsecured floating rate notes due 2021 299.6 — — 299.1 Senior unsecured notes due 2023 — 298.7 — 298.3 Senior secured notes due 2026 — 298.0 — 297.8 Senior unsecured notes due 2028 — 694.5 — 694.1 Senior secured notes due 2025 — 1,183.4 — — Present value of finance lease obligations 34.2 128.0 25.8 121.3 Other 1.7 56.4 1.6 57.8 Total $ 335.5 $ 2,659.0 $ 50.2 $ 2,984.1

Pension and Other Post-Retire_2

Pension and Other Post-Retirement Benefits (Tables)	9 Months Ended
	Oct. 01, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Change in projected benefit obligations	. Pension and Other Post-Retirement Benefits Defined Benefit Plans For the Three Months Ended For the Nine Components of Net Periodic Pension Expense/(Income) October 1, September 26, October 1, September 26, Service cost $ 0.2 $ 0.3 $ 0.7 $ 1.0 Interest cost 5.4 10.0 20.1 30.0 Expected return on plan assets (16.6) (16.6) (49.5) (50.0) Amortization of net loss — 0.1 0.2 0.5 Curtailment loss (gain) (2) — — 33.9 (0.1) Settlement loss (3) 4.2 — 9.3 — Special termination benefits (1) (1.6) (5.5) 31.4 9.7 Net periodic pension expense (income) $ (8.4) $ (11.7) $ 46.1 $ (8.9) Other Benefits For the Three For the Nine Components of Other Benefit Expense October 1, September 26, October 1, September 26, Service cost $ 0.1 $ 0.2 $ 0.5 $ 0.7 Interest cost 0.2 0.3 0.7 1.0 Amortization of prior service cost (0.2) (0.2) (0.6) (0.7) Amortization of net gain (0.4) (0.6) (1.3) (1.8) Curtailment (gain) loss (2) — — (0.2) — Special termination benefits (1) $ — $ — $ 12.0 $ — Net periodic other benefit expense (income) $ (0.3) $ (0.3) $ 11.1 $ (0.8) (1) Special termination benefits for the three and nine months ending October 1, 2020 is a combination of pension value plan and postretirement medical plan changes offset by a reduction in the Company's net benefit obligation. For the three months and nine months ending October 1, 2020 special termination benefits, curtailment accounting, and the remeasurement of the pension assets and obligations resulted in a $(31.9) and $0.4 impact to OCI, respectively. For the three months and nine months ending October 1, 2020, retiree medical resulted in a $0.0 and $2.3 impact to OCI, respectively. This impact is included in the Company’s Condensed Consolidated Statements of Comprehensive (Loss) Income. The Company expects to record additional charges related to settlement accounting in subsequent 2020 quarters tied to cash payments made. (2) The Company's Voluntary Retirement Program ("VRP") resulted in an estimated 16% and 12% reduction in future working lifetime for the pension value plan and postretirement medical plan resulting in a curtailment accounting charge of $0.0 and $33.7 for the three and nine months ended October 1, 2020, respectively and is included in other (expense) income in the Company's Condensed Consolidated Statements of Operations. (3) Under ASC 715 - Compensation Retirement Benefits

Equity (Tables)

Equity (Tables)	9 Months Ended
	Oct. 01, 2020
Stockholders' Equity Note [Abstract]
Basic and Diluted Earnings per share	The following table sets forth the computation of basic and diluted earnings per share: For the Three Months Ended October 1, 2020 September 26, 2019 Income Shares Per Share Income Shares Per Share Basic EPS (Loss) income available to common stockholders $ (155.5) 103.9 $ (1.50) $ 131.2 103.5 $ 1.27 Income allocated to participating securities — — 0.1 0.1 Net (loss) income $ (155.5) $ 131.3 Diluted potential common shares 1.0 Diluted EPS Net (loss) income $ (155.5) 103.9 $ (1.50) $ 131.3 104.6 $ 1.26
Schedule of Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Loss is summarized by component as follows: As of As of October 1, 2020 December 31, 2019 Pension $ (52.8) $ (53.1) Interest swaps (1.2) (0.6) SERP/Retiree medical 13.7 17.1 Foreign currency impact on long term intercompany loan (14.3) (13.1) Currency translation adjustment (75.0) (59.5) Total accumulated other comprehensive loss $ (129.6) $ (109.2)

Commitments, Contingencies an_2

Commitments, Contingencies and Guarantees (Tables)	9 Months Ended
	Oct. 01, 2020
Commitments Contingencies And Guarantees [Abstract]
Service warranty roll forward	The following is a roll forward of the service warranty and extraordinary rework balance at October 1, 2020: Balance, December 31, 2019 $ 64.7 Charges to costs and expenses 2.9 Payouts (1.4) Exchange rate (0.2) Balance, October 1, 2020 $ 66.0

Other Income (Expense), Net (Ta

Other Income (Expense), Net (Tables)	9 Months Ended
	Oct. 01, 2020
Other Nonoperating Income (Expense) [Abstract]
Other Income Expense Net	Other (expense) income, net is summarized as follows: For the Three For the Nine October 1, September 26, October 1, September 26, Kansas Development Finance Authority bond $ 0.6 $ 0.8 $ 2.3 $ 2.8 Rental and miscellaneous income — — 0.1 0.1 Interest income 0.9 2.6 9.0 8.8 Foreign currency (losses) gains (1) (3.4) (17.9) 1.4 (9.9) Loss on foreign currency contract and interest rate swaps (10.6) (0.5) (10.5) (18.3) Litigation settlement — — — 13.5 Loss on sale of accounts receivable (2.0) (6.5) (6.7) (18.7) Pension (loss) income (2) 9.0 12.0 (56.4) 9.8 ASC 326 credit loss reserve (3.6) — (3.6) — Other (0.9) — (1.0) — Total $ (10.0) $ (9.5) $ (65.4) $ (11.9)

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Oct. 01, 2020
Segment Reporting [Abstract]
Segment Information	The following table shows segment revenues and operating income for the three months and nine months ended October 1, 2020 and September 26, 2019: Three Months Ended Nine Months Ended October 1, September 26, October 1, September 26, Segment Revenues Fuselage Systems $ 421.1 $ 1,005.3 $ 1,299.7 $ 3,171.7 Propulsion Systems 170.8 520.9 565.6 1,525.5 Wing Systems 168.3 391.0 582.2 1,197.4 All Other 46.1 2.7 80.7 9.2 $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8 Segment Operating Income (Loss) Fuselage Systems (1) $ (96.7) $ 105.8 $ (434.6) $ 380.5 Propulsion Systems (2) (15.6) 111.7 (38.2) 304.9 Wing Systems (3) (23.2) 53.9 (52.1) 177.1 All Other 19.1 1.3 28.9 2.5 $ (116.4) $ 272.7 $ (496.0) $ 865.0 SG&A (52.8) (53.6) (179.2) (173.6) Research and development (7.5) (12.6) (28.1) (36.0) Unallocated cost of sales (0.2) (0.4) (8.1) 9.7 Total operating income $ (176.9) $ 206.1 $ (711.4) $ 665.1 (1) The three and nine months ended October 1, 2020 includes excess capacity production costs of $42.0 and $143.8, respectively, related to the temporary B737 MAX production schedule changes, abnormal costs of $(7.4) and $19.1, respectively, for temporary workforce adjustments as a result of COVID-19 production pause net of U.S. employee retention credit, $6.6 and $39.1, respectively, of restructuring costs, and $0 and $22.5, respectively, from loss on the disposition of assets. (2) The three and nine months ended October 1, 2020 includes excess capacity production costs of $17.5 and $50.8, respectively, related to the temporary B737 MAX production schedule changes, abnormal costs of $(2.9) and $7.3, respectively, for temporary workforce adjustments as a result of COVID-19 production paus e net of U.S employee retention credit , and $3.8 and $14.2, respectively, of restructuring costs. (3) The three and nine months ended October 1, 2020 includes excess capacity production costs of $13.1 and $34.2, respectively, related to the temporary B737 MAX and A320 production schedule changes, abnormal costs of $(0.6) and $7.4, respectively, for temporary workforce adjustments as a result of COVID-19, net of U.S employee retention credit and U.K government subsidies, $9.1 and $15.1, respectively, of restructuring costs, and $0 and $0.4, respectively, from loss on the disposition of assets.

Condensed Consolidating Finan_2

Condensed Consolidating Financial Information (Tables)	9 Months Ended
	Oct. 01, 2020
Condensed Financial Information Disclosure [Abstract]
Condensed Income Statement	Condensed Consolidating Statements of Operations For the Three Months Ended October 1, 2020 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Revenue $ — $ 705.5 $ 56.7 $ 130.0 $ (85.9) $ 806.3 Operating costs and expenses Cost of sales — 812.0 54.7 122.6 (85.9) 903.4 Selling, general and administrative 3.3 43.8 0.7 5.0 — 52.8 Restructuring cost — 10.9 0.2 8.4 — 19.5 Research and development — 6.2 0.1 1.2 — 7.5 Loss on disposal of assets — — — — — — Total operating costs and expenses 3.3 872.9 55.7 137.2 (85.9) 983.2 Operating (loss) income (3.3) (167.4) 1.0 (7.2) — (176.9) Interest expense and financing fee amortization — (53.0) — (0.4) 0.4 (53.0) Other (expense) income, net — (6.2) (0.1) (3.3) (0.4) (10.0) (Loss) income before income taxes and equity in net (loss) income of affiliate and subsidiaries (3.3) (226.6) 0.9 (10.9) — (239.9) Income tax benefit (provision) 1.2 82.8 (0.2) 1.4 — 85.2 (Loss) income before equity in net (loss) income of affiliate and subsidiaries (2.1) (143.8) 0.7 (9.5) — (154.7) Equity in net (loss) income of affiliate — — — (0.8) — (0.8) Equity in net (loss) income of subsidiaries (153.4) (9.6) — — 163.0 — Net (loss) income (155.5) (153.4) 0.7 (10.3) 163.0 (155.5) Other comprehensive (loss) income 51.7 51.7 — 18.7 (70.4) 51.7 Comprehensive (loss) income $ (103.8) $ (101.7) $ 0.7 $ 8.4 $ 92.6 $ (103.8) Condensed Consolidating Statements of Operations For the Three Months Ended September 26, 2019 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Revenue $ — $ 1,747.5 96.4 $ 218.3 $ (142.3) $ 1,919.9 Operating costs and expenses Cost of sales — 1,511.6 93.3 185.0 (142.3) 1,647.6 Selling, general and administrative 2.6 46.4 0.7 3.9 — 53.6 Research and development — 11.0 0.2 1.4 — 12.6 Total operating costs and expenses 2.6 1,569.0 94.2 190.3 (142.3) 1,713.8 Operating income (loss) (2.6) 178.5 2.2 28.0 — 206.1 Interest expense and financing fee amortization — (23.6) — (0.9) 0.9 (23.6) Other income (expense), net — (12.1) — 3.5 (0.9) (9.5) Income (loss) before income taxes and equity in net income of affiliate and subsidiaries (2.6) 142.8 2.2 30.6 — 173.0 Income tax (provision) benefit 0.6 (36.9) (0.5) (4.9) — (41.7) Income (loss) before equity in net income of affiliate and subsidiaries (2.0) 105.9 1.7 25.7 — 131.3 Equity in net income of affiliate — — — — — — Equity in net income (loss) of subsidiaries 133.3 27.4 — — (160.7) — Net income 131.3 133.3 1.7 25.7 (160.7) 131.3 Other comprehensive income (loss) 21.5 21.5 — (13.9) (7.6) 21.5 Comprehensive income (loss) $ 152.8 $ 154.8 $ 1.7 $ 11.8 $ (168.3) $ 152.8
Condensed Balance Sheet	Condensed Consolidating Balance Sheet October 1, 2020 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Assets Cash and cash equivalents $ — $ 1,258.7 $ — $ 182.6 $ — $ 1,441.3 Restricted cash — 1.3 — — — 1.3 Accounts receivable, net — 517.9 66.1 182.4 (377.6) 388.8 Contract assets, short-term — 279.0 — 54.6 — 333.6 Inventory, net — 816.1 161.8 205.4 — 1,183.3 Other current assets — 251.9 — 7.7 — 259.6 Total current assets — 3,124.9 227.9 632.7 (377.6) 3,607.9 Property, plant and equipment, net — 1,683.6 273.8 190.0 — 2,147.4 Right of use assets — 37.3 7.0 0.1 — 44.4 Contract assets, long-term — 4.1 — — — 4.1 Pension assets, net — 378.9 — 25.3 — 404.2 Deferred income taxes — 136.6 — 0.1 — 136.7 Goodwill — 76.0 — 2.4 — 78.4 Intangible assets, net — 29.5 — — — 29.5 Investment in subsidiary 1,172.0 818.8 — — (1,990.8) — Other assets — 226.1 — 112.5 (186.8) 151.8 Total assets $ 1,172.0 $ 6,515.8 $ 508.7 $ 963.1 $ (2,555.2) $ 6,604.4 Liabilities Accounts payable $ — $ 503.5 $ 234.8 $ 122.7 $ (377.9) $ 483.1 Accrued expenses — 240.9 1.7 46.9 0.3 289.8 Profit sharing — 33.9 — 4.2 — 38.1 Current portion of long-term debt — 333.5 0.2 1.8 — 335.5 Operating lease liabilities, short-term — 4.9 0.6 — — 5.5 Advance payments, short-term — 20.1 — — — 20.1 Contract liabilities, short-term — 100.9 — — — 100.9 Forward loss provision, long-term — 163.4 — 6.5 — 169.9 Deferred revenue and other deferred credits, short-term — 15.4 — 0.3 — 15.7 Other current liabilities — 25.6 — 12.1 — 37.7 Total current liabilities — 1,442.1 237.3 194.5 (377.6) 1,496.3 Long-term debt — 2,650.2 0.6 94.4 (86.2) 2,659.0 Operating lease liabilities, long-term — 32.7 6.4 — — 39.1 Advance payments, long-term — 325.0 — — — 325.0 Pension/OPEB obligation — 47.0 — — — 47.0 Contract liabilities, long-term — 371.7 — — — 371.7 Forward loss provision, long-term — 303.8 — — — 303.8 Deferred grant income liability - non-current — 8.9 — 18.5 — 27.4 Deferred revenue and other deferred credits — 28.2 — 5.4 — 33.6 Deferred income taxes — — — 10.0 — 10.0 Other liabilities — 214.2 — 5.9 (100.6) 119.5 Total equity 1,172.0 1,092.0 264.4 634.4 (1,990.8) 1,172.0 Total liabilities and stockholders’ equity $ 1,172.0 $ 6,515.8 $ 508.7 $ 963.1 $ (2,555.2) $ 6,604.4 Condensed Consolidating Balance Sheet December 31, 2019 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Assets Cash and cash equivalents $ — $ 2,193.3 $ — $ 157.2 $ — $ 2,350.5 Restricted cash — 0.3 — — — 0.3 Accounts receivable, net — 565.4 50.5 250.7 (320.2) 546.4 Inventory, net — 786.8 136.8 195.2 — 1,118.8 Contract assets, short-term — 458.8 — 69.5 — 528.3 Other current assets — 93.5 — 5.2 — 98.7 Total current assets — 4,098.1 187.3 677.8 (320.2) 4,643.0 Property, plant and equipment, net — 1,773.0 306.3 192.4 — 2,271.7 Right of use assets — 41.2 7.5 0.2 — 48.9 Contract assets, long-term — 6.4 — — — 6.4 Pension assets, net — 424.2 — 24.9 — 449.1 Deferred income taxes — 106.3 — 0.2 — 106.5 Goodwill — — — 2.4 — 2.4 Intangible assets, net — 1.2 — — — 1.2 Investment in subsidiary 1,761.9 838.4 — — (2,600.3) — Other assets — 147.6 — 116.0 (186.8) 76.8 Total assets $ 1,761.9 $ 7,436.4 $ 501.1 $ 1,013.9 $ (3,107.3) $ 7,606.0 Liabilities Accounts payable $ — $ 977.1 $ 226.3 $ 175.1 $ (320.2) $ 1,058.3 Accrued expenses — 210.0 0.8 29.4 — 240.2 Profit sharing — 76.9 — 7.6 — 84.5 Current portion of long-term debt — 48.4 0.2 1.6 — 50.2 Operating lease liabilities, short-term — 5.3 0.6 0.1 — 6.0 Advance payments, short-term — 21.6 — — — 21.6 Contract liabilities, short-term — 158.3 — — — 158.3 Forward loss provision, long-term — 83.9 — — — 83.9 Deferred revenue and other deferred credits, short-term — 14.5 — 0.3 — 14.8 Other current liabilities — 29.3 2.1 11.5 — 42.9 Total current liabilities — 1,625.3 230.0 225.6 (320.2) 1,760.7 Long-term debt — 2,974.7 0.9 94.7 (86.2) 2,984.1 Operating lease liabilities, long-term — 36.0 6.9 0.1 — 43.0 Advance payments, long-term — 333.3 — — — 333.3 Pension/OPEB obligation — 35.7 — — — 35.7 Contract liabilities, long-term — 356.3 — — — 356.3 Forward loss provision, long-term — 163.5 — — — 163.5 Deferred grant income liability - non-current — 9.2 — 19.8 — 29.0 Deferred revenue and other deferred credits — 30.4 — 4.0 — 34.4 Deferred income taxes — — — 8.3 — 8.3 Other liabilities — 190.1 — 6.3 (100.6) 95.8 Total equity 1,761.9 1,681.9 263.3 655.1 (2,600.3) 1,761.9 Total liabilities and stockholders’ equity $ 1,761.9 $ 7,436.4 $ 501.1 $ 1,013.9 $ (3,107.3) $ 7,606.0
Condensed Cash Flow Statement	Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Assets Cash and cash equivalents $ — $ 2,193.3 $ — $ 157.2 $ — $ 2,350.5 Restricted cash — 0.3 — — — 0.3 Accounts receivable, net — 565.4 50.5 250.7 (320.2) 546.4 Inventory, net — 786.8 136.8 195.2 — 1,118.8 Contract assets, short-term — 458.8 — 69.5 — 528.3 Other current assets — 93.5 — 5.2 — 98.7 Total current assets — 4,098.1 187.3 677.8 (320.2) 4,643.0 Property, plant and equipment, net — 1,773.0 306.3 192.4 — 2,271.7 Right of use assets — 41.2 7.5 0.2 — 48.9 Contract assets, long-term — 6.4 — — — 6.4 Pension assets, net — 424.2 — 24.9 — 449.1 Deferred income taxes — 106.3 — 0.2 — 106.5 Goodwill — — — 2.4 — 2.4 Intangible assets, net — 1.2 — — — 1.2 Investment in subsidiary 1,761.9 838.4 — — (2,600.3) — Other assets — 147.6 — 116.0 (186.8) 76.8 Total assets $ 1,761.9 $ 7,436.4 $ 501.1 $ 1,013.9 $ (3,107.3) $ 7,606.0 Liabilities Accounts payable $ — $ 977.1 $ 226.3 $ 175.1 $ (320.2) $ 1,058.3 Accrued expenses — 210.0 0.8 29.4 — 240.2 Profit sharing — 76.9 — 7.6 — 84.5 Current portion of long-term debt — 48.4 0.2 1.6 — 50.2 Operating lease liabilities, short-term — 5.3 0.6 0.1 — 6.0 Advance payments, short-term — 21.6 — — — 21.6 Contract liabilities, short-term — 158.3 — — — 158.3 Forward loss provision, long-term — 83.9 — — — 83.9 Deferred revenue and other deferred credits, short-term — 14.5 — 0.3 — 14.8 Other current liabilities — 29.3 2.1 11.5 — 42.9 Total current liabilities — 1,625.3 230.0 225.6 (320.2) 1,760.7 Long-term debt — 2,974.7 0.9 94.7 (86.2) 2,984.1 Operating lease liabilities, long-term — 36.0 6.9 0.1 — 43.0 Advance payments, long-term — 333.3 — — — 333.3 Pension/OPEB obligation — 35.7 — — — 35.7 Contract liabilities, long-term — 356.3 — — — 356.3 Forward loss provision, long-term — 163.5 — — — 163.5 Deferred grant income liability - non-current — 9.2 — 19.8 — 29.0 Deferred revenue and other deferred credits — 30.4 — 4.0 — 34.4 Deferred income taxes — — — 8.3 — 8.3 Other liabilities — 190.1 — 6.3 (100.6) 95.8 Total equity 1,761.9 1,681.9 263.3 655.1 (2,600.3) 1,761.9 Total liabilities and stockholders’ equity $ 1,761.9 $ 7,436.4 $ 501.1 $ 1,013.9 $ (3,107.3) $ 7,606.0 Condensed Consolidating Statements of Cash Flows For the Nine Months Ended October 1, 2020 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Operating activities Net cash used in operating activities $ — $ (634.9) $ (16.2) $ 38.3 $ — $ (612.8) Investing activities Purchase of property, plant and equipment — (53.4) (1.3) (15.7) — (70.4) Acquisition, net of cash acquired — (117.9) — — — (117.9) Other — 0.4 — 4.5 — 4.9 Net cash used in investing activities — (170.9) (1.3) (11.2) — (183.4) Financing activities Proceeds from issuance of debt — 1,200.0 — — — 1,200.0 Proceeds from revolving credit facility — — — — — — Customer financing — 10.0 — — — 10.0 Principal payments of debt — (21.2) (0.2) (1.3) — (22.7) Payments on term loans — (439.7) — — — (439.7) Payments on revolving credit facility — (800.0) — — — (800.0) Proceeds (payments) from intercompany debt — (20.9) 17.7 3.2 — — Taxes paid related to net share settlement of awards — (14.0) — — — (14.0) Proceeds (payments) from subsidiary for purchase of treasury stock (0.1) 0.1 — — — — Purchase of treasury stock 0.1 — — — — 0.1 Proceeds (payments) from subsidiary for dividends paid 14.4 (14.4) — — — — Dividends paid (14.4) — — — — (14.4) Proceeds from issuance of ESPP stock — 2.6 — — — 2.6 Debt issuance costs — (27.6) — — — (27.6) Other — — 0.1 — 0.1 Net cash (used in) provided by financing activities — (125.1) 17.5 2.0 — (105.6) Effect of exchange rate changes on cash and cash equivalents — 0.5 — (3.8) — (3.3) Net (decrease) increase in cash and cash equivalents for the period — (930.4) — 25.3 — (905.1) Cash, cash equivalents, and restricted cash, beginning of period — 2,210.0 — 157.2 — 2,367.2 Cash, cash equivalents, and restricted cash, end of period $ — $ 1,279.6 $ — $ 182.5 $ — $ 1,462.1 Condensed Consolidating Statements of Cash Flows For the Nine Months Ended September 26, 2019 Holdings Spirit Spirit NC Non-Guarantor Consolidating Total Operating activities Net cash provided by operating activities $ — $ 571.3 $ 53.3 $ 94.0 $ — $ 718.6 Investing activities Purchase of property, plant and equipment — (94.0) (7.7) (17.1) — (118.8) Other — 0.1 — — — 0.1 Net cash used in investing activities — (93.9) (7.7) (17.1) — (118.7) Financing activities Proceeds from issuance of debt — 250.0 — — — 250.0 Proceeds from revolving credit facility — 100.0 — — — 100.0 Principal payments of debt — (7.8) (0.2) (0.5) — (8.5) Payments on term loans — (5.2) — — — (5.2) Payments on revolving credit facility — (100.0) — — — (100.0) Proceeds (payments) from intercompany debt — 56.1 (45.4) (10.7) — — Taxes paid related to net share settlement of awards — (12.1) — — — (12.1) Proceeds (payments) from subsidiary for dividends paid 37.8 (37.6) — (0.2) — — Dividends paid (37.8) — — — — (37.8) Proceeds (payments) from subsidiary for purchase of treasury stock 75.0 (75.0) — — — — Purchase of treasury stock (75.0) — — — — (75.0) Proceeds from issuance of ESPP stock — 1.3 — — — 1.3 Other — 0.8 — — — 0.8 Net cash provided by (used in) financing activities — 170.5 (45.6) (11.4) — 113.5 Effect of exchange rate changes on cash and cash equivalents — (13.2) — (0.3) (13.5) Net increase in cash and cash equivalents for the period — 634.7 — 65.2 — 699.9 Cash, cash equivalents, and restricted cash, beginning of period — 725.5 — 68.6 — 794.1 Cash, cash equivalents, and restricted cash, end of period — 1,360.2 — 133.8 — 1,494.0

Changes in Estimates (Details)

Changes in Estimates (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019
Change In Estimate [Line Items]
Changes in Contract Estimates, aggregate, Affecting earnings from Continuing Operations, per Share diluted	$ (0.77)	$ (0.31)	$ (2.33)	$ (0.18)
Change In Accounting Estimate, aggregate	$ (123.8)	$ (41.8)	$ (372.8)	$ (23.6)
Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	4.6	(13)	(30.6)	(1.8)
Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(128.4)	(28.8)	(342.2)	(21.8)
Fuselage Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	8.8	(14.4)	(18.9)	(2)
Fuselage Systems [Member] | Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(92)	(18.8)	(260.3)	(13.8)
Wing Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	0.4	(0.4)	(3.1)	1.7
Wing Systems [Member] | Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(21.5)	(6)	(47.7)	(4.9)
Propulsion Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(4.6)	1.8	(8.6)	(1.5)
Propulsion Systems [Member] | Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	$ (14.9)	$ (4)	$ (34.2)	$ (3.1)

Accounts Receivable, net (Detai

Accounts Receivable, net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019	Dec. 31, 2019
Accounts Receivable, after Allowance for Credit Loss, Current [Abstract]
Transfer of Financial Assets Accounted for as Sales, Amount Derecognized	$ 1,516.3		$ 1,516.3
Trade receivables	366.9		366.9		$ 515.2
Other	26.5		26.5		32.6
Less: allowance for doubtful accounts	(4.6)		(4.6)		(1.4)
Accounts receivable, net	388.8		388.8		$ 546.4
Gain (Loss) on Sale of Accounts Receivable	$ 2	$ 6.5	$ 6.7	$ 18.7

Contract with customer, asset_2

Contract with customer, asset and liability (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 806.3	$ 1,919.9	$ 2,528.2	$ 5,903.8
Contract with Customer, Liability, Revenue Recognized			$ 91	109.7
Disaggregation of Revenue [Table Text Block]			Disaggregation of Revenue The Company disaggregates revenue based on the method of measuring satisfaction of the performance obligation either over time or at a point in time, based upon the location where products and services are transferred to the customer, and based upon major customer. The Company’s principal operating segments and related revenue are noted in Note 22, Segment Information . The following tables show disaggregated revenues for the periods ended October 1, 2020 and September 26, 2019: For the Three Months Ended For the Nine Revenue October 1, September 26, October 1, September 26, Contracts with performance obligations satisfied over time $ 510.6 $ 1,466.9 $ 1,511.9 $ 4,491.8 Contracts with performance obligations satisfied at a point in time 295.7 453.0 1,016.3 1,412.0 Total Revenue $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8 The following table disaggregates revenue by major customer: For the Three Months Ended For the Nine Customer October 1, September 26, October 1, September 26, Boeing $ 493.8 $ 1,542.0 $ 1,539.9 $ 4,705.1 Airbus 160.1 284.1 575.3 934.0 Other 152.4 93.8 413.0 264.7 Total Revenue $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8 The following table disaggregates revenue based upon the location where control of products are transferred to the customer: For the Three Months Ended For the Nine Location October 1, September 26, October 1, September 26, United States $ 642.0 $ 1,620.6 $ 1,936.4 $ 4,935.8 International United Kingdom 103.6 177.4 358.2 577.6 Other 60.7 121.9 233.6 390.4 Total International 164.3 299.3 591.8 968.0 Total Revenue $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8
Contract with Customer, Liability, Revenue Recognized			$ 91	109.7
Contract with Customer, Asset, before Allowance for Credit Loss	337.7	588.7	337.7	588.7	$ 534.7	$ 523.5
change in contract asset			(197)	65.2
Contract with Customer, Liability	(472.6)	(510.9)	(472.6)	(510.9)	$ (514.6)	$ (527.7)
change in contract liability			42	16.8
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	510.6	1,466.9	1,511.9	4,491.8
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 295.7	$ 453	$ 1,016.3	$ 1,412

Revenue (Details)

Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Disaggregation of Revenue [Table Text Block]			Disaggregation of Revenue The Company disaggregates revenue based on the method of measuring satisfaction of the performance obligation either over time or at a point in time, based upon the location where products and services are transferred to the customer, and based upon major customer. The Company’s principal operating segments and related revenue are noted in Note 22, Segment Information . The following tables show disaggregated revenues for the periods ended October 1, 2020 and September 26, 2019: For the Three Months Ended For the Nine Revenue October 1, September 26, October 1, September 26, Contracts with performance obligations satisfied over time $ 510.6 $ 1,466.9 $ 1,511.9 $ 4,491.8 Contracts with performance obligations satisfied at a point in time 295.7 453.0 1,016.3 1,412.0 Total Revenue $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8 The following table disaggregates revenue by major customer: For the Three Months Ended For the Nine Customer October 1, September 26, October 1, September 26, Boeing $ 493.8 $ 1,542.0 $ 1,539.9 $ 4,705.1 Airbus 160.1 284.1 575.3 934.0 Other 152.4 93.8 413.0 264.7 Total Revenue $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8 The following table disaggregates revenue based upon the location where control of products are transferred to the customer: For the Three Months Ended For the Nine Location October 1, September 26, October 1, September 26, United States $ 642.0 $ 1,620.6 $ 1,936.4 $ 4,935.8 International United Kingdom 103.6 177.4 358.2 577.6 Other 60.7 121.9 233.6 390.4 Total International 164.3 299.3 591.8 968.0 Total Revenue $ 806.3 $ 1,919.9 $ 2,528.2 $ 5,903.8
Revenues	$ 806.3	$ 1,919.9	$ 2,528.2	$ 5,903.8
Remaining in Current Year [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	579.2		579.2
2021 [Member] [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	2,755.3		2,755.3
2022 [Member] [Member] [Domain]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	3,707.3		3,707.3
2021 and after [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	7,466.6		7,466.6
Transferred over Time [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues	510.6	1,466.9	1,511.9	4,491.8
Transferred at Point in Time [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues	295.7	453	1,016.3	1,412
Boeing [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues	493.8	1,542	1,539.9	4,705.1
Airbus [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues	160.1	284.1	575.3	934
Other Customer [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues	$ 152.4	$ 93.8	$ 413	$ 264.7

Inventory (Details)

Inventory (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Oct. 01, 2020	Oct. 01, 2020	Dec. 31, 2019
Summary Of Inventories [Abstract]
Raw materials	$ 304	$ 304	$ 253.1
Work-in-process	838.3	838.3	822.8
Finished goods	14.2	14.2	14.5
Product inventory	1,156.5	1,156.5	1,090.4
Capitalized pre-production	26.8	26.8	28.4
Total inventory, net	1,183.3	1,183.3	1,118.8
Inventory Valuation Reserves	49.2	49.2	39
Costs Incurred in Anticipation of Contracts	184.9	184.9	$ 157.2
Excess Capacity Costs- B737MAX and A320 Production Schedules	72.6	228.8
Abnormal Costs- COVID19 production suspension	$ (10.9)	$ 33.8

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Millions	Oct. 01, 2020	Dec. 31, 2019
Property, plant and equipment, net
Land	$ 17.6	$ 15.9
Buildings (including improvements)	937.2	924
Machinery and equipment	1,973.2	1,941.5
Tooling	1,025.9	1,047.4
Capitalized software	275.3	277.8
Construction-in-progress	196.1	192.8
Total	4,425.3	4,399.4
Less: accumulated depreciation	(2,277.9)	(2,127.7)
Property, plant and equipment, net	$ 2,147.4	$ 2,271.7

Property, Plant and Equipment_3

Property, Plant and Equipment (Details Textual) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019
Property, Plant and Equipment [Line Items]
Gain (Loss) on Disposition of Property Plant Equipment	$ 0	$ 0	$ 22.9	$ 0
Property Plant And Equipment Textuals [Abstract]
Capitalized interest related to construction-in-progress	1.3	1.5	3.8	5.1
Repair and maintenance costs	25.7	32.9	82.7	102.7
Depreciation expense related to capitalized software	4.1	$ 4.3	12.6	$ 13.3
B-737 [Member]
Property, Plant and Equipment [Line Items]
Gain (Loss) on Disposition of Property Plant Equipment			(19.2)
A350 XWB [Member]
Property, Plant and Equipment [Line Items]
Gain (Loss) on Disposition of Property Plant Equipment			(3.7)
Fuselage Systems [Member]
Property, Plant and Equipment [Line Items]
Gain (Loss) on Disposition of Property Plant Equipment	0		22.5
Wing Systems [Member]
Property, Plant and Equipment [Line Items]
Gain (Loss) on Disposition of Property Plant Equipment	$ 0		$ (0.4)

Leases (Details)

Leases (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019	Dec. 31, 2019
Lessee Disclosure [Abstract]
Operating Lease, Weighted Average Remaining Lease Term	9 years 10 months 24 days		9 years 10 months 24 days		10 years 2 months 12 days
Finance Lease, Weighted Average Remaining Lease Term	5 years 7 months 6 days		5 years 7 months 6 days		6 years 6 months
Assets and Liabilities, Lessee [Abstract]
Operating Lease, Liability, Current	$ 5.5		$ 5.5		$ 6
Operating Lease, Liability, Noncurrent	39.1		39.1		43
Operating Lease, Liability	44.6		44.6
finance lease, Right-of-Use Asset, gross	212.3		212.3		165.5
Finance Lease, Right-of-Use Asset, Accumulated Amortization	(39.6)		(39.6)		(23.5)
Finance Lease, Right-of-Use Asset, after Accumulated Amortization	172.7		172.7		$ 142
Finance Lease, Liability	162.2		162.2
Lessee, Finance Lease, Lease Not yet Commenced, Description	$ 26		$ 26
Operating Lease, Weighted Average Discount Rate, Percent	5.60%		5.60%		5.60%
Finance Lease, Weighted Average Discount Rate, Percent	4.40%		4.40%		4.30%
Finance Lease, Liability, Payment, Due [Abstract]
Finance Lease, Liability, to be Paid, Remainder of Fiscal Year	$ 10.3		$ 10.3
Finance Lease, Liability, to be Paid, Year Two	40		40
Finance Lease, Liability, to be Paid, Year Three	36.1		36.1
Finance Lease, Liability, to be Paid, Year Four	31.4		31.4
Finance Lease, Liability, to be Paid, Year Five	25.2		25.2
Finance Lease, Liability, to be Paid, after Year Five	40.2		40.2
Finance Lease, Liability, Payment, Due	183.2		183.2
Lease Imputed Interest Due- Financing	(21)		(21)
Cash Flow, Operating Activities, Lessee [Abstract]
Operating lease cost	2.1	$ 2.4	6.5	$ 6.7
Finance Lease, Interest Payment on Liability	1.6	0.8	4.7	1.7
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	0.1	0.9	0.3	1.6
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year	2.1		2.1
Lessee, Operating Lease, Liability, to be Paid, Year Two	7.5		7.5
Lessee, Operating Lease, Liability, to be Paid, Year Three	7.2		7.2
Lessee, Operating Lease, Liability, to be Paid, Year Four	6.1		6.1
Lessee, Operating Lease, Liability, to be Paid, Year Five	5.5		5.5
Lessee, Operating Lease, Liability, to be Paid, after Year Five	30.3		30.3
Lessee, Operating Lease, Liability, to be Paid	58.7		58.7
Lease Imputed Interest Due- Operating	(14.1)		(14.1)
Lease, Cost [Abstract]
Operating Lease, Cost	2.2	2.4	6.6	6.7
Finance Lease, Right-of-Use Asset, Amortization	5.7	2.9	16	7.1
Finance Lease, Interest Expense	1.6	0.7	4.7	1.7
Lease, Cost	9.5	6	27.3	15.5
Cash Flow, Financing Activities, Lessee [Abstract]
Finance Lease, Principal Payments	$ 7.7	$ 3.4	$ 21.4	$ 7.2

Other Assets (Details)

Other Assets (Details) - USD ($) $ in Millions	9 Months Ended
	Oct. 01, 2020	Dec. 31, 2019	Sep. 26, 2019	Dec. 31, 2018
Other Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 34.8	$ 4.8
Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year	0.5
Finite-Lived Intangible Asset, Expected Amortization, Year Two	2.1
Finite-Lived Intangible Asset, Expected Amortization, Year Three	2.1
Finite-Lived Intangible Asset, Expected Amortization, Year Four	2.1
Finite-Lived Intangible Asset, Expected Amortization, Year Five	2.1
Finite-Lived Intangible Assets, Amortization Expense, Year Six	$ 2.1
Finite-Lived Intangible Assets, Remaining Amortization Period	14 years 1 month 6 days
Intangible assets
Deferred financing costs, net	$ 6.1	4.8
Goodwill	78.4	2.4
Income Taxes Receivable, Noncurrent	72.7	0
Equity in net assets of affiliates	3.9	7.7
Customer Supply Agreement	11.2	11.5
Restricted Cash, Noncurrent	19.5	16.4	$ 16.4	$ 20.2
Other	38.4	36.4
Total other long term assets	151.8	76.8
Prepaid Expense, Current	15.5	19.3
Income Taxes Receivable, Current	240.9	74.2
Other Assets, Miscellaneous, Current	3.2	5.2
Intangible Assets, Net (Excluding Goodwill)	29.5	1.2
Other Assets, Current	259.6	98.7
Patents [Member]
Other Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	2	2
Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year	0
Finite-Lived Intangible Asset, Expected Amortization, Year Two	0
Finite-Lived Intangible Asset, Expected Amortization, Year Three	0
Finite-Lived Intangible Asset, Expected Amortization, Year Four	0
Finite-Lived Intangible Asset, Expected Amortization, Year Five	0
Finite-Lived Intangible Assets, Amortization Expense, Year Six	0
Intangible assets
Less: Accumulated amortization	(2)	(1.9)
Favorable Leasehold [Member]
Other Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	2.8	2.8
Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year	0
Finite-Lived Intangible Asset, Expected Amortization, Year Two	0.1
Finite-Lived Intangible Asset, Expected Amortization, Year Three	0.1
Finite-Lived Intangible Asset, Expected Amortization, Year Four	0.1
Finite-Lived Intangible Asset, Expected Amortization, Year Five	0.1
Finite-Lived Intangible Assets, Amortization Expense, Year Six	$ 0.1
Finite-Lived Intangible Assets, Remaining Amortization Period	8 years 9 months 18 days
Intangible assets
Less: Accumulated amortization	$ (1.8)	(1.7)
Debt issuance costs [Member]
Intangible assets
Deferred financing costs	48.3	41.7
Less: Accumulated amortization-deferred financing costs	(42.2)	(36.9)
Developed Technology [Member]
Other Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	30	0
Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year	0.5
Finite-Lived Intangible Asset, Expected Amortization, Year Two	2
Finite-Lived Intangible Asset, Expected Amortization, Year Three	2
Finite-Lived Intangible Asset, Expected Amortization, Year Four	2
Finite-Lived Intangible Asset, Expected Amortization, Year Five	2
Finite-Lived Intangible Assets, Amortization Expense, Year Six	$ 2
Finite-Lived Intangible Assets, Remaining Amortization Period	14 years 3 months 18 days
Intangible assets
Less: Accumulated amortization	$ (1.5)	$ 0

Other Assets (Details Textuals)

Other Assets (Details Textuals) - USD ($) $ in Millions	Oct. 01, 2020	Dec. 31, 2019
Goodwill [Line Items]
Goodwill	$ 78.4	$ 2.4
Spirit Europe Goodwill [Member]
Goodwill [Line Items]
Goodwill	2.4	2.4
FMI Goodwill [Member] [Member]
Goodwill [Line Items]
Goodwill	76	0
Wing Systems [Member]
Goodwill [Line Items]
Goodwill	2.4	$ 2.4
FMI [Member]
Goodwill [Line Items]
Goodwill	76
FMI [Member] | Fuselage Systems [Member]
Goodwill [Line Items]
Goodwill	42.9
FMI [Member] | Propulsion Systems [Member]
Goodwill [Line Items]
Goodwill	33.1
Wing Systems [Member]
Goodwill [Line Items]
Goodwill	2.4
Propulsion Systems [Member]
Goodwill [Line Items]
Goodwill	33.1
Fuselage Systems [Member]
Goodwill [Line Items]
Goodwill	$ 42.9

Advance Payments and Deferred_2

Advance Payments and Deferred Revenue/Credits (Details) $ in Millions	Oct. 01, 2020USD ($)
advance payments [Line Items]
Customer advances- B787 program	$ 212
Total Payment [Member]
advance payments [Line Items]
Customer advances- B737 program	123
Total Payment [Member]
advance payments [Line Items]
Customer advances- B737 program	225
Production Stabilization [Member]
advance payments [Line Items]
Customer advances- B737 program	70
To be repaid in 2021 [Member]
advance payments [Line Items]
Customer advances- B737 program	10
Prepayment of shipset deliveries [Member]
advance payments [Line Items]
Customer advances- B737 program	$ 155

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	Oct. 01, 2020	Dec. 31, 2019	Sep. 26, 2019
Carrying amount and estimated fair value of long term debt
Carrying Amount	$ 2,774.2	$ 2,827.8
Fair Value	2,609.7	2,885.7
Long-term Line of Credit, Noncurrent	0	800
Lines of Credit, Fair Value Disclosure		800	$ 0
Senior Secured Notes Due 2025 [Member]
Carrying amount and estimated fair value of long term debt
Fair Value	1,204.2	0
Senior Notes	1,183.4
Senior Notes, Noncurrent	1,183.4	0
Senior Notes, Current	0	0
Secured Debt Term A [Member]
Debt Instrument [Line Items]
Secured Debt, Current	0	22.8
Secured Long-term Debt, Noncurrent	0	415.7
Carrying amount and estimated fair value of long term debt
Carrying Amount	0	438.5
Fair Value	0	440.1
Senior Unsecured Notes Due 2023 [Domain]
Carrying amount and estimated fair value of long term debt
Fair Value	267	307.2
Senior Notes	298.7
Senior Notes, Noncurrent	298.7	298.3
Senior Notes, Current	0	0
Senior Unsecured Notes Due 2026 [Member]
Carrying amount and estimated fair value of long term debt
Fair Value	279.9	305.6
Senior Notes	298
Senior Notes, Noncurrent	298	297.8
Senior Notes, Current	0	0
SeniorUnsecuredNotesDue2028 [Member] [Member]
Carrying amount and estimated fair value of long term debt
Fair Value	575.3	734.4
Senior Notes, Noncurrent	694.5	694.1
SeniorUnsecuredFloatingRateNotes [Member]
Carrying amount and estimated fair value of long term debt
Fair Value	283.3	298.4
Senior Notes	299.6
Senior Notes, Noncurrent	0	299.1
Senior Notes, Current	$ 299.6	$ 0

Derivative and Hedging Activi_2

Derivative and Hedging Activities (Details 1) $ in Millions	3 Months Ended	9 Months Ended
	Oct. 01, 2020USD ($)	Oct. 01, 2020USD ($)
Derivative [Line Items]
Cash Flow Hedge Derivative Instrument Liabilities at Fair Value	$ 1.7	$ 1.7
Maximum Length of Time Hedged in Cash Flow Hedge	9 months
Derivatives, Fair Value [Line Items]
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	$ 0	$ 14.2

Derivative and Hedging Activi_3

Derivative and Hedging Activities (Details Textual) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Oct. 01, 2020	Oct. 01, 2020
Derivatives Fair Value [Line Items]
Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	$ 1.6	$ 3
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months		$ 1.7
Loss on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring	$ 10.4

Debt (Details)

Debt (Details) - USD ($) $ in Millions	Oct. 01, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Outstanding Balance Term Loan	$ 0
Outstanding Balance Revolver	0
Long-term Line of Credit, Noncurrent	0	$ 800
Long Term Debt And Capital Lease Obligations Current And Non Current [Abstract]
Capital Lease Obligations, Current	34.2	25.8
Capital Lease Obligations, Noncurrent	128	121.3
Other Long-term Debt, Current	1.7	1.6
Other Long-term Debt, Noncurrent	56.4	57.8
Long-term Debt and Lease Obligation, Current	335.5	50.2
Long-term Debt and Lease Obligation	2,659	2,984.1
Secured Debt Term A [Member]
Debt Disclosure [Abstract]
Secured Debt, Current	0	22.8
Senior Unsecured Notes Due 2023 [Domain]
Debt Disclosure [Abstract]
Senior Notes	298.7
Debt Instrument, Face Amount	300
Long Term Debt And Capital Lease Obligations Current And Non Current [Abstract]
Senior Notes, Current	0	0
Senior Notes, Noncurrent	298.7	298.3
Debt Instrument, Face Amount	300
Senior Notes	298.7
SeniorUnsecuredNotesDue2028 [Member] [Member]
Long Term Debt And Capital Lease Obligations Current And Non Current [Abstract]
Senior Notes, Noncurrent	694.5	694.1
Senior Unsecured Notes Due 2026 [Member]
Debt Disclosure [Abstract]
Senior Notes	298
Debt Instrument, Face Amount	300
Long Term Debt And Capital Lease Obligations Current And Non Current [Abstract]
Senior Notes, Current	0	0
Senior Notes, Noncurrent	298	297.8
Debt Instrument, Face Amount	300
Senior Notes	298
Senior Unsecured Notes Due 2028 [Member]
Debt Disclosure [Abstract]
Senior Notes	694.5
Debt Instrument, Face Amount	700
Long Term Debt And Capital Lease Obligations Current And Non Current [Abstract]
Senior Notes, Current	0	0
Senior Notes, Noncurrent	694.5	694.1
Debt Instrument, Face Amount	700
Senior Notes	694.5
Senior Secured Notes Due 2025 [Member]
Debt Disclosure [Abstract]
Senior Notes	1,183.4
Debt Instrument, Face Amount	1,200
Long Term Debt And Capital Lease Obligations Current And Non Current [Abstract]
Senior Notes, Current	0	0
Senior Notes, Noncurrent	1,183.4	0
Debt Instrument, Face Amount	1,200
Senior Notes	1,183.4
Total Debt [Member]
Long Term Debt And Capital Lease Obligations Current And Non Current [Abstract]
Long-term Debt and Lease Obligation, Current	335.5	50.2
Long-term Debt and Lease Obligation	2,659	2,984.1
SeniorUnsecuredFloatingRateNotes [Member]
Debt Disclosure [Abstract]
Senior Notes	299.6
Debt Instrument, Face Amount	300
Long Term Debt And Capital Lease Obligations Current And Non Current [Abstract]
Senior Notes, Current	299.6	0
Senior Notes, Noncurrent	0	$ 299.1
Debt Instrument, Face Amount	300
Senior Notes	$ 299.6

Debt (Details Textual)

Debt (Details Textual) - USD ($) $ in Millions	9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Dec. 31, 2019
Debt Instrument [Line Items]
Outstanding Balance Term Loan	$ 0
Proceeds from (Payments for) Other Financing Activities	0.1	$ 0.8
Restricted Cash and Cash Equivalents	1.3		$ 0.3
Proceeds from Issuance of Senior Long-term Debt	1,200	250
Proceeds from Lines of Credit	0	100
Repayments of Lines of Credit	800	$ 100
Long-term Debt	2,774.2		2,827.8
2018 Amended Restated Credit Agreement [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	1,256
Senior Unsecured Notes Due 2023 [Domain]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	300
Senior Notes	298.7
Senior Notes, Current	0		0
Senior Unsecured Notes Due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	300
Senior Notes	298
Senior Notes, Current	0		0
2018 Revolver [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	800
2018 Term Loan A [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	206
Delayed Draw Term Loan [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	250
Senior Secured Notes Due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	1,200
Senior Notes	1,183.4
Senior Notes, Current	0		0
Secured Debt Term A [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 0		$ 438.5

Pension and Other Post-Retire_3

Pension and Other Post-Retirement Benefits Pension and Other Post-Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	$ 0		$ 33.7
Defined Benefit Plan Estimated Future Employer Contributions Remainder Of Year			9.5
Expected UK Pension Plan Contribution For Year			1.8
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax	0		2.3
Defined Benefit Plan, Service Cost	0.1	$ 0.2	0.5	$ 0.7
Defined Benefit Plan, Interest Cost	0.2	0.3	0.7	1
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(0.2)	(0.2)	(0.6)	(0.7)
Defined Benefit Plan, Amortization of Gain (Loss)	(0.4)	(0.6)	(1.3)	(1.8)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	0	0	(0.2)	0
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	0	0	12	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(0.3)	(0.3)	11.1	(0.8)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax	31.9		0.4
Defined Benefit Plan, Service Cost	0.2	0.3	0.7	1
Defined Benefit Plan, Interest Cost	5.4	10	20.1	30
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(16.6)	(16.6)	(49.5)	(50)
Defined Benefit Plan, Amortization of Gain (Loss)	0	0.1	0.2	0.5
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	0	0	33.9	(0.1)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	4.2	0	9.3	0
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	(1.6)	(5.5)	31.4	9.7
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (8.4)	$ (11.7)	$ 46.1	$ (8.9)

Stock Compensation (Details)

Stock Compensation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019
LTIA AND Prior Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Company recognized total stock compensation expense, net of forfeitures	$ 6.2	$ 7.5	$ 17.1	$ 22.6
Board of Directors Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted			64,750
Fair Value Of Shares Granted			$ 1.3
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period			12,877
Grant date value of shares vested			$ 1.1
Class A [Member] | Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period			489,889
Grant date value of shares vested			$ 33.2
Class A [Member] | union ratification bonus [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted			38,249
Fair Value Of Shares Granted			$ 2.5
Class A [Member] | Market Based LTIA [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted			198,980
Fair Value Of Shares Granted			$ 6.2
Class A [Member] | Service Based LTIA [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted			499,945
Fair Value Of Shares Granted			$ 20.6
Class A [Member] | Performance Based LTIA [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted			176,815
Fair Value Of Shares Granted			$ 9.3

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Deferred Tax Assets, Net	$ 126.7		$ 98.2
Effective Income Tax Rate Reconciliation, Percent	37.30%	21.20%

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended					6 Months Ended	9 Months Ended
	Oct. 01, 2020	Jul. 02, 2020	Apr. 02, 2020	Sep. 26, 2019	Mar. 28, 2019	Jun. 27, 2019	Oct. 01, 2020	Sep. 26, 2019	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 925						$ 925
Common Stock, Dividends, Per Share, Declared	$ 0.01	$ 0.01	$ 0.01	$ 0.12	$ 0.12	$ 0.12
Basic EPS
Income available to common shareholders	$ (155.5)			$ 131.2			$ (574.4)	$ 462.1
Income available to common shareholders, shares	103.9			103.5			103.8	103.6
Income available to common shareholders, per share amount	$ (1.50)			$ 1.27			$ (5.53)	$ 4.46
Income allocated to participating securities	$ 0			$ 0.1			$ 0	$ 0.3
Income allocated to participating securities, shares	0			0.1			0	0.1
Net (loss) income	$ (155.5)			$ 131.3			$ (574.4)	$ 462.4
Diluted potential common shares				1				1.1
Diluted EPS
Net (loss) income	$ (155.5)			$ 131.3			$ (574.4)	$ 462.4
Shares	103.9			104.6			103.8	104.8
Diluted (in dollars per share)	$ (1.50)			$ 1.26			$ (5.53)	$ 4.41
Equity Textuals [Abstract]
Noncontrolling interest	$ 0.5						$ 0.5		$ 0.5
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(129.6)						(129.6)		(109.2)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	0.7			$ 0.7			2	$ 2
Pension [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(52.8)						(52.8)		(53.1)
Accumulated Interest Rate Swaps [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(1.2)						(1.2)		(0.6)
SERP and Retiree medical [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	13.7						13.7		17.1
Foreign currency impact on long term intercompany loan [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(14.3)						(14.3)		(13.1)
Currency translation adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (75)						$ (75)		$ (59.5)

Commitments, Contingencies an_3

Commitments, Contingencies and Guarantees (Details) - USD ($) $ in Millions	9 Months Ended
	Oct. 01, 2020	Dec. 31, 2019	Sep. 26, 2019	Dec. 31, 2018
Commitments Contingencies And Guarantees [Abstract]
Restricted Cash, Noncurrent	$ 19.5	$ 16.4	$ 16.4	$ 20.2
Service warranty roll forward
Product Warranty And Extraordinary Rework	64.7
Charges to costs and expenses	(2.9)
Product Warranty Accrual, Payments	(1.4)
Product Warranty And Extraordinary Rework	66
Product Warranty Extraordinary Rework Accrual Currency Translation Increase Decrease	(0.2)
Commitments Contingencies And Guarantees Textuals [Abstract]
Outstanding amount of guarantees	19.4	$ 21.5
Product Liability Accrual, Component Amount	8.1
Product Liability Contingency, Loss Exposure in Excess of Accrual, Best Estimate	$ 12.1

Other Income (Expense), Net (De

Other Income (Expense), Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019
Other Income (Loss) [Line Items]
Kansas Development Finance Authority bond	$ 0.6	$ 0.8	$ 2.3	$ 2.8
Rental and miscellaneous income	0	0	0.1	0.1
Interest Income, Other	0.9	2.6	9	8.8
Foreign currency (losses) gains (1)	(3.4)	(17.9)	1.4	(9.9)
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	(10.6)	(0.5)	(10.5)	(18.3)
Gain (Loss) on Sale of Accounts Receivable	(2)	(6.5)	(6.7)	(18.7)
Pension Income (Expense) without Service Cost	9	12	(56.4)	9.8
Accounts Receivable, Credit Loss Expense (Reversal)	(3.6)	0	(3.6)	0
Other Cost and Expense, Operating	(0.9)	0	(1)	0
VRP pension expense	2.6	5.5	86.4	(9.7)
Other Income- Other	0	0	0	13.5
Total	$ (10)	$ (9.5)	$ (65.4)	$ (11.9)

Segment Information (Details)

Segment Information (Details)	3 Months Ended		9 Months Ended
	Oct. 01, 2020USD ($)	Sep. 26, 2019USD ($)	Oct. 01, 2020USD ($)segment	Sep. 26, 2019USD ($)
Segment Reporting Information [Line Items]
Restructuring Charges	$ 19,500,000	$ 0	$ 68,400,000	$ 0
Excess Capacity Costs- B737MAX and A320 Production Schedules	72,600,000		228,800,000
Abnormal Costs- COVID19 production suspension	(10,900,000)		33,800,000
Cost of Goods and Services Sold	903,400,000	1,647,600,000	2,941,000,000	5,029,100,000
Gain (Loss) on Disposition of Property Plant Equipment	0	0	(22,900,000)	0
Segment Revenues
Segment Revenues	806,300,000	1,919,900,000	2,528,200,000	5,903,800,000
Segment Operating Income
Business Segment Operating Income	(116,400,000)	272,700,000	(496,000,000)	865,000,000
Segment Information Unallocated Corporate Selling General And Administrative	(52,800,000)	(53,600,000)	(179,200,000)	(173,600,000)
Segment Information Unallocated Research And Development	(7,500,000)	(12,600,000)	(28,100,000)	(36,000,000)
Segment Information Unallocated Cost Of Sales	(200,000)	(400,000)	(8,100,000)	9,700,000
Operating (loss) income	(176,900,000)	206,100,000	$ (711,400,000)	665,100,000
Segment Reporting Information, Additional Information [Abstract]
Number Of Principal Segments | segment			3
Percentage Of Net Revenue Derived From Two Largest Customers			81.00%
Fuselage Systems [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	6,600,000		$ 39,100,000
Excess Capacity Costs- B737MAX and A320 Production Schedules	42,000,000		143,800,000
Abnormal Costs- COVID19 production suspension	(7,400,000)		19,100,000
Gain (Loss) on Disposition of Property Plant Equipment	0		(22,500,000)
Segment Revenues
Segment Revenues	421,100,000	1,005,300,000	1,299,700,000	3,171,700,000
Segment Operating Income
Business Segment Operating Income	(96,700,000)	105,800,000	(434,600,000)	380,500,000
Propulsion Systems [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	3,800,000		14,200,000
Excess Capacity Costs- B737MAX and A320 Production Schedules	17,500,000		50,800,000
Abnormal Costs- COVID19 production suspension	(2,900,000)		7,300,000
Segment Revenues
Segment Revenues	170,800,000	520,900,000	565,600,000	1,525,500,000
Segment Operating Income
Business Segment Operating Income	(15,600,000)	111,700,000	(38,200,000)	304,900,000
Wing Systems [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	9,100,000		15,100,000
Excess Capacity Costs- B737MAX and A320 Production Schedules	13,100,000		34,200,000
Abnormal Costs- COVID19 production suspension	(600,000)		7,400,000
Gain (Loss) on Disposition of Property Plant Equipment	0		400,000
Segment Revenues
Segment Revenues	168,300,000	391,000,000	582,200,000	1,197,400,000
Segment Operating Income
Business Segment Operating Income	(23,200,000)	53,900,000	(52,100,000)	177,100,000
Other Systems [Member]
Segment Revenues
Segment Revenues	46,100,000	2,700,000	80,700,000	9,200,000
Segment Operating Income
Business Segment Operating Income	$ 19,100,000	$ 1,300,000	$ 28,900,000	$ 2,500,000

Restructuring Charges (Details)

Restructuring Charges (Details) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 19,500,000	$ 0	$ 68,400,000	$ 0
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	47,500,000
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Costs			20,900,000
Fuselage Systems [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	6,600,000		39,100,000
Propulsion Systems [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	3,800,000		14,200,000
Wing Systems [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 9,100,000		$ 15,100,000

Acquisition (Details)

Acquisition (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Oct. 01, 2020	Sep. 26, 2019	Dec. 31, 2019
Business Acquisition [Line Items]
Revenues	$ 806.3	$ 1,919.9	$ 2,528.2	$ 5,903.8
Net Income (Loss) Attributable to Parent	$ (155.5)	$ 131.3	$ (574.4)	$ 462.4
Business Acquisition, Percentage of Voting Interests Acquired	100.00%		100.00%
Goodwill	$ 78.4		$ 78.4		$ 2.4
Earnings Per Share, Diluted	$ (1.50)	$ 1.26	$ (5.53)	$ 4.41
FMI [Member]
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Net Income (Loss)	$ (155.5)	$ 131.9	$ (574.3)	$ 464.1
Business Acquisition, Pro Forma Revenue	806.3	$ 1,927.4	2,529	$ 5,926.8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	3.5		3.5
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	5.3		$ 5.3
Business Acquisition, Effective Date of Acquisition			Jan. 10, 2020
Business Acquisition, Name of Acquired Entity			FMI
Business Combination, Consideration Transferred			$ 121.6
Business Combination, Reason for Business Combination			Acquiring FMI aligns with the Company's strategic growth objectives to diversify its customer base and expand the current defense business.
Business Acquisition, Description of Acquired Entity			Founded in 1969 and headquartered in Biddeford, ME, FMI is an industry-leader in the design and manufacture of complex composite solutions that are primarily used in aerospace applications. Over the past 50 years, FMI has developed a portfolio related to its high temperature composites. FMI's main operations focus on multidirectional reinforced composites that enable high-temperature applications such as thermal protection systems, re-entry vehicle nose tips, and rocket motor throats and nozzles. Their unique capabilities have positioned them as a leader in 3D woven carbon-carbon high-temperature materials for hypersonic missiles, which the Department of Defense has identified as a national priority.
cumulative transaction costs	1.5		$ 1.5
Business Acquisition, Transaction Costs	0.5		0.5
Goodwill	76		76
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	5.3		5.3
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual			43.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory	1.9		1.9
business combination, recognized identifiable assets liabilities assumed, contract assets	5.6		5.6
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	0.5		0.5
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	12.3		12.3
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	30		30
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	0.2		0.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	135.3		135.3
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable	1.8		1.8
business combination, recognized identifiable assets acquired and liabilities assumed, income tax payable	1.4		1.4
business combination, recognized identifiable assets acquired and liabilities assumed, contract liabilities	2.2		2.2
business combination, recognized identifiable assets acquired and liabilities assumed, accrued payroll and benefits	0.6		0.6
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	0.2		0.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities	7.5		7.5
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other	0.2		0.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	13.9		13.9
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	$ 121.4		$ 121.4
Business Acquisition, Pro Forma Earnings Per Share, Diluted	$ (1.50)	$ 1.26	$ (5.53)	$ 4.43
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual			$ 6.7
Asco [Member]
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs	$ 17.3	$ 8.4	17.3	$ 8.4
Bombardier [Member]
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs	6.2		6.2
Technology-Based Intangible Assets [Member] | FMI [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	30		$ 30
Weighted Average Amortization Period Intangible Assets			15
Fuselage Systems [Member]
Business Acquisition [Line Items]
Revenues	421.1	1,005.3	$ 1,299.7	3,171.7
Fuselage Systems [Member] | FMI [Member]
Business Acquisition [Line Items]
Goodwill	42.9		42.9
Propulsion Systems [Member]
Business Acquisition [Line Items]
Revenues	170.8	$ 520.9	565.6	$ 1,525.5
Propulsion Systems [Member] | FMI [Member]
Business Acquisition [Line Items]
Goodwill	$ 33.1		$ 33.1

Condensed Consolidating Finan_3

Condensed Consolidating Financial Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended
	Oct. 01, 2020	Sep. 26, 2019	Jun. 27, 2019	Oct. 01, 2020	Sep. 26, 2019	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 806.3	$ 1,919.9		$ 2,528.2	$ 5,903.8
Operating costs and expenses
Cost of sales	903.4	1,647.6		2,941	5,029.1
Selling, general and administrative	52.8	53.6		179.2	173.6
Restructuring Charges	19.5	0		68.4	0
Research and development	7.5	12.6		28.1	36
Gain (Loss) on Disposition of Property Plant Equipment	0	0		22.9	0
Total operating costs and expenses	983.2	1,713.8		3,239.6	5,238.7
Operating income	(176.9)	206.1		(711.4)	665.1
Interest expense and financing fee amortization	(53)	(23.6)		(133.8)	(66.1)
Other expense, net	(10)	(9.5)		(65.4)	(11.9)
Income (loss) before income taxes and equity in net loss of affiliates and subsidiaries	(239.9)	173		(910.6)	587.1
Income tax benefit (provision)	85.2	(41.7)		340	(124.7)
Income (loss) Before Equity In Net Income (Loss) Of Affiliates and Subsidiaries	(154.7)	131.3		(570.6)	462.4
Equity in net loss of affiliate	(0.8)	0		(3.8)	0
Equity in net income of subsidiaries	0	0		0	0
Net (loss) income	(155.5)	131.3		(574.4)	462.4
Total other comprehensive income (loss)	51.7	21.5		(20.4)	16.7
Comprehensive Income, Net of Tax, Attributable to Parent	(103.8)	152.8		(594.8)	479.1
Assets
Cash and cash equivalents	1,462.1	1,494	$ 1,494	1,462.1	1,494	$ 2,367.2	$ 794.1
Restricted Cash and Cash Equivalents	1.3			1.3		0.3
Accounts receivable, net	388.8			388.8		546.4
Unbilled Receivables, Current	333.6			333.6		528.3
Inventory	1,183.3			1,183.3		1,118.8
Other current assets	259.6			259.6		98.7
Total current assets	3,607.9			3,607.9		4,643
Property, plant and equipment, net	2,147.4			2,147.4		2,271.7
Operating Lease, Right-of-Use Asset	44.4			44.4		48.9
Unbilled Receivable, Non Current	4.1			4.1		6.4
Pension assets	404.2			404.2		449.1
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	136.7			136.7		106.5
Goodwill	78.4			78.4		2.4
Intangible Assets, Net (Excluding Goodwill)	29.5			29.5		1.2
Deferred income taxes	151.8			151.8		76.8
Other assets	6,604.4			6,604.4		7,606
Total assets
Liabilities	483.1			483.1		1,058.3
Accounts payable	289.8			289.8		240.2
Accrued expenses	38.1			38.1		84.5
Profit sharing	335.5			335.5		50.2
Operating Lease, Liability, Current	5.5			5.5		6
Operating lease liabilities, short-term	20.1			20.1		21.6
Billings in Excess of Cost, Noncurrent	371.7			371.7		356.3
Billings in Excess of Cost, Current	100.9			100.9		158.3
Provision for Loss on Contracts	169.9			169.9		83.9
Forward loss provision, short-term	15.7			15.7		14.8
Deferred grant income liability — current	37.7			37.7		42.9
Other current liabilities	1,496.3			1,496.3		1,760.7
Long-term debt	2,659			2,659		2,984.1
Operating Lease, Liability, Noncurrent	39.1			39.1		43
Advance payments, long-term	325			325		333.3
Pension/OPEB obligation	47			47		35.7
Provision for Loss on Contacts, Non Current	303.8			303.8		163.5
Deferred grant income liability - non-current	27.4			27.4		29
Deferred revenue and other deferred credits	33.6			33.6		34.4
Deferred Tax Liabilities, Net, Noncurrent	10			10		8.3
Deferred income taxes	119.5			119.5		95.8
Total equity	1,172			1,172		1,761.9
Total liabilities and equity	6,604.4			6,604.4		7,606
Operating activities
Net cash (used in) operating activities				(612.8)	718.6
Investing activities
Purchase of property, plant and equipment				(70.4)	(118.8)
Payments for (Proceeds from) Other Investing Activities				4.9	0.1
Payments to Acquire Businesses, Net of Cash Acquired				(117.9)	0
Payments for (Proceeds from) Other Investing Activities				4.9
Net cash used in investing activities				(183.4)	(118.7)
Proceeds from (Repayments of) Other Debt				10	0
Proceeds from Lines of Credit				0	100
Proceeds from (Payments for) Other Financing Activities				0.1	0.8
Proceeds from Issuance of Senior Long-term Debt				(1,200)	(250)
Financing activities
Principal payments of debt				(22.7)	(8.5)
Repayments of Debt				(439.7)	(5.2)
Repayments of Lines of Credit				(800)	(100)
Collection on (repayment of) intercompany debt					0
Payment, Tax Withholding, Share-based Payment Arrangement				(14)	(12.1)
Proceeds (payments) from subsidiary for purchase of treasury stock				0	0
Payments for Repurchase of Common Stock				0.1
Proceeds from subsidiary (payments to Parent) to pay dividends				0	0
Payments of Dividends				(14.4)	(37.8)
Proceeds from Stock Plans				2.6	1.3
Net cash (used in ) provided by financing activities				(105.6)	113.5
Payments of Financing Costs				(27.6)	0
Payments for Repurchase of Common Stock					75
Effect of exchange rate changes on cash and cash equivalents				(3.3)	(13.5)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect				(905.1)	699.9
Cash and cash equivalents, beginning of period			773.6	2,350.5	773.6
Cash, cash equivalents, and restricted cash, end of period	1,441.3	1,477.3		1,441.3	1,477.3
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	(85.9)	(142.3)		(334.2)	(504.9)
Operating costs and expenses
Cost of sales	(85.9)	(142.3)		(334.2)	(504.9)
Selling, general and administrative				0
Restructuring Charges	0			0
Research and development				0
Gain (Loss) on Disposition of Property Plant Equipment	0			0
Total operating costs and expenses	(85.9)	(142.3)		(334.2)	(504.9)
Interest expense and financing fee amortization	0.4	0.9		1.8	2.8
Other expense, net	(0.4)	(0.9)		(1.8)	(2.8)
Income tax benefit (provision)				0
Equity in net loss of affiliate				0
Equity in net income of subsidiaries	163	(160.7)		570	(556.2)
Net (loss) income	163	(160.7)		570	(556.2)
Total other comprehensive income (loss)	(70.4)	(7.6)		37.2	1.3
Comprehensive Income, Net of Tax, Attributable to Parent	92.6	(168.3)		607.2	(554.9)
Assets
Restricted Cash and Cash Equivalents	0			0		0
Accounts receivable, net	(377.6)			(377.6)		(320.2)
Unbilled Receivables, Current	0			0		0
Inventory						0
Total current assets	(377.6)			(377.6)		(320.2)
Operating Lease, Right-of-Use Asset	0			0		0
Unbilled Receivable, Non Current	0			0		0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent						0
Goodwill	0			0		0
Intangible Assets, Net (Excluding Goodwill)	0			0		0
Investment in subsidiary	(1,990.8)			(1,990.8)		(2,600.3)
Deferred income taxes	(186.8)			(186.8)		(186.8)
Other assets	(2,555.2)			(2,555.2)		(3,107.3)
Total assets
Liabilities	(377.9)			(377.9)		(320.2)
Accounts payable	0.3			0.3
Operating Lease, Liability, Current	0			0		0
Billings in Excess of Cost, Noncurrent	0			0		0
Billings in Excess of Cost, Current	0			0		0
Provision for Loss on Contracts	0			0		0
Other current liabilities	(377.6)			(377.6)		(320.2)
Long-term debt	(86.2)			(86.2)		(86.2)
Operating Lease, Liability, Noncurrent	0			0		0
Provision for Loss on Contacts, Non Current	0			0		0
Deferred Tax Liabilities, Net, Noncurrent	0			0		0
Deferred income taxes	(100.6)			(100.6)		(100.6)
Total equity	(1,990.8)			(1,990.8)		(2,600.3)
Total liabilities and equity	(2,555.2)			(2,555.2)		(3,107.3)
Investing activities
Payments for (Proceeds from) Other Investing Activities					0
Payments to Acquire Businesses, Net of Cash Acquired				0
Payments for (Proceeds from) Other Investing Activities				0
Proceeds from (Repayments of) Other Debt				0
Proceeds from Lines of Credit					0
Proceeds from (Payments for) Other Financing Activities				0	0
Proceeds from Issuance of Senior Long-term Debt				0
Financing activities
Principal payments of debt					0
Repayments of Lines of Credit					0
Collection on (repayment of) intercompany debt					0
Payment, Tax Withholding, Share-based Payment Arrangement				0	0
Proceeds (payments) from subsidiary for purchase of treasury stock				0	0
Proceeds from subsidiary (payments to Parent) to pay dividends				0	0
Payments of Dividends				0	0
Proceeds from Stock Plans				0	0
Payments of Financing Costs				0
Payments for Repurchase of Common Stock					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
Cost of sales				0
Selling, general and administrative	3.3	2.6		11.7	9.6
Restructuring Charges	0			0
Research and development				0
Gain (Loss) on Disposition of Property Plant Equipment	0			0
Total operating costs and expenses	3.3	2.6		11.7	9.6
Operating income	(3.3)	(2.6)		(11.7)	(9.6)
Interest expense and financing fee amortization				0
Other expense, net				0
Income (loss) before income taxes and equity in net loss of affiliates and subsidiaries	(3.3)	(2.6)		(11.7)	(9.6)
Income tax benefit (provision)	1.2	0.6		(4.4)	2.2
Income (loss) Before Equity In Net Income (Loss) Of Affiliates and Subsidiaries	(2.1)	(2)		(7.3)	(7.4)
Equity in net loss of affiliate				0
Equity in net income of subsidiaries	(153.4)	133.3		(567.1)	469.8
Net (loss) income	(155.5)	131.3		(574.4)	462.4
Total other comprehensive income (loss)	51.7	21.5		(20.4)	16.7
Comprehensive Income, Net of Tax, Attributable to Parent	(103.8)	152.8		(594.8)	479.1
Assets
Restricted Cash and Cash Equivalents	0			0		0
Unbilled Receivables, Current	0			0		0
Inventory						0
Operating Lease, Right-of-Use Asset	0			0		0
Unbilled Receivable, Non Current	0			0		0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent						0
Goodwill	0			0		0
Intangible Assets, Net (Excluding Goodwill)	0			0		0
Investment in subsidiary	1,172			1,172		1,761.9
Other assets	1,172			1,172		1,761.9
Total assets
Operating Lease, Liability, Current						0
Billings in Excess of Cost, Noncurrent	0			0		0
Billings in Excess of Cost, Current	0			0
Provision for Loss on Contracts	0			0		0
Operating Lease, Liability, Noncurrent						0
Provision for Loss on Contacts, Non Current	0			0		0
Deferred Tax Liabilities, Net, Noncurrent	0			0		0
Total equity	1,172			1,172		1,761.9
Total liabilities and equity	1,172			1,172		1,761.9
Investing activities
Payments for (Proceeds from) Other Investing Activities					0
Payments to Acquire Businesses, Net of Cash Acquired				0
Payments for (Proceeds from) Other Investing Activities				0
Proceeds from (Repayments of) Other Debt				0
Proceeds from (Payments for) Other Financing Activities					0
Financing activities
Principal payments of debt					0
Repayments of Lines of Credit					0
Collection on (repayment of) intercompany debt					0
Payment, Tax Withholding, Share-based Payment Arrangement				0	0
Proceeds (payments) from subsidiary for purchase of treasury stock				(0.1)	(75)
Payments for Repurchase of Common Stock				0.1
Proceeds from subsidiary (payments to Parent) to pay dividends				14.4	37.8
Payments of Dividends				(14.4)	(37.8)
Proceeds from Stock Plans				0	0
Payments of Financing Costs				0
Payments for Repurchase of Common Stock					(75)
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	130	218.3		456	719.9
Operating costs and expenses
Cost of sales	122.6	185		430.4	609.9
Selling, general and administrative	5	3.9		14	12.2
Restructuring Charges	8.4			9.8
Research and development	1.2	1.4		2.9	3.9
Gain (Loss) on Disposition of Property Plant Equipment	0			0
Total operating costs and expenses	137.2	190.3		457.1	626
Operating income	(7.2)	28		(1.1)	93.9
Interest expense and financing fee amortization	(0.4)	(0.9)		(1.9)	(3)
Other expense, net	(3.3)	3.5		1.6	4.6
Income (loss) before income taxes and equity in net loss of affiliates and subsidiaries	(10.9)	30.6		(1.4)	95.5
Income tax benefit (provision)	1.4	(4.9)		(1.4)	(14.9)
Income (loss) Before Equity In Net Income (Loss) Of Affiliates and Subsidiaries	(9.5)	25.7			80.6
Equity in net loss of affiliate	(0.8)			(3.8)
Equity in net income of subsidiaries				0
Net (loss) income	(10.3)	25.7		(3.8)	80.6
Total other comprehensive income (loss)	18.7	(13.9)		(16.8)	(18)
Comprehensive Income, Net of Tax, Attributable to Parent	8.4	11.8		(20.6)	62.6
Assets
Cash and cash equivalents	182.5		133.8	182.5		157.2	68.6
Restricted Cash and Cash Equivalents	0			0		0
Accounts receivable, net	182.4			182.4		250.7
Unbilled Receivables, Current	54.6			54.6		69.5
Inventory	205.4			205.4		195.2
Other current assets	7.7			7.7		5.2
Total current assets	632.7			632.7		677.8
Property, plant and equipment, net	190			190		192.4
Operating Lease, Right-of-Use Asset	0.1			0.1		0.2
Unbilled Receivable, Non Current	0			0		0
Pension assets	25.3			25.3		24.9
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	0.1			0.1		0.2
Goodwill	2.4			2.4		2.4
Intangible Assets, Net (Excluding Goodwill)	0			0		0
Deferred income taxes	112.5			112.5		116
Other assets	963.1			963.1		1,013.9
Total assets
Liabilities	122.7			122.7		175.1
Accounts payable	46.9			46.9		29.4
Accrued expenses	4.2			4.2		7.6
Profit sharing	1.8			1.8		1.6
Operating Lease, Liability, Current	0			0		0.1
Billings in Excess of Cost, Noncurrent	0			0		0
Billings in Excess of Cost, Current	0			0		0
Provision for Loss on Contracts	6.5			6.5		0
Forward loss provision, short-term	0.3			0.3		0.3
Deferred grant income liability — current	12.1			12.1		11.5
Other current liabilities	194.5			194.5		225.6
Long-term debt	94.4			94.4		94.7
Operating Lease, Liability, Noncurrent	0			0		0.1
Provision for Loss on Contacts, Non Current	0			0		0
Deferred grant income liability - non-current	18.5			18.5		19.8
Deferred revenue and other deferred credits	5.4			5.4		4
Deferred Tax Liabilities, Net, Noncurrent	10			10		8.3
Deferred income taxes	5.9			5.9		6.3
Total equity	634.4			634.4		655.1
Total liabilities and equity	963.1			963.1		1,013.9
Operating activities
Net cash (used in) operating activities				38.3	94
Investing activities
Purchase of property, plant and equipment				(15.7)	(17.1)
Payments for (Proceeds from) Other Investing Activities					0
Payments to Acquire Businesses, Net of Cash Acquired				0
Payments for (Proceeds from) Other Investing Activities				4.5
Net cash used in investing activities				(11.2)	(17.1)
Proceeds from (Repayments of) Other Debt				0
Proceeds from Lines of Credit					0
Proceeds from (Payments for) Other Financing Activities				0.1	0
Proceeds from Issuance of Senior Long-term Debt				0
Financing activities
Principal payments of debt				(1.3)	0.5
Repayments of Lines of Credit					0
Collection on (repayment of) intercompany debt				3.2	10.7
Payment, Tax Withholding, Share-based Payment Arrangement				0	0
Proceeds (payments) from subsidiary for purchase of treasury stock				0	0
Proceeds from subsidiary (payments to Parent) to pay dividends				0	(0.2)
Payments of Dividends				0	0
Proceeds from Stock Plans				0	0
Net cash (used in ) provided by financing activities				2	(11.4)
Payments of Financing Costs				0
Payments for Repurchase of Common Stock					0
Effect of exchange rate changes on cash and cash equivalents				(3.8)	(0.3)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect				25.3	65.2
Cash and cash equivalents, beginning of period				157.2
Cash, cash equivalents, and restricted cash, end of period	182.6			182.6
Subsidiary Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	705.5	1,747.5		2,182.2	5,346.5
Operating costs and expenses
Cost of sales	812	1,511.6		2,628.4	4,592.5
Selling, general and administrative	43.8	46.4		151.6	149.5
Restructuring Charges	10.9			58.1
Research and development	6.2	11		24.9	31.3
Gain (Loss) on Disposition of Property Plant Equipment	0			(19.2)
Total operating costs and expenses	872.9	1,569		2,882.2	4,773.3
Operating income	(167.4)	178.5		(700)	573.2
Interest expense and financing fee amortization	(53)	(23.6)		(133.7)	(65.9)
Other expense, net	(6.2)	(12.1)		(65)	(13.7)
Income (loss) before income taxes and equity in net loss of affiliates and subsidiaries	(226.6)	142.8		(898.7)	493.6
Income tax benefit (provision)	82.8	(36.9)		(334.5)	(110.2)
Income (loss) Before Equity In Net Income (Loss) Of Affiliates and Subsidiaries	(143.8)	105.9		(564.2)	383.4
Equity in net loss of affiliate				0
Equity in net income of subsidiaries	(9.6)	27.4		(2.9)	86.4
Net (loss) income	(153.4)	133.3		(567.1)	469.8
Total other comprehensive income (loss)	51.7	21.5		(20.4)	16.7
Comprehensive Income, Net of Tax, Attributable to Parent	(101.7)	154.8		(587.5)	486.5
Assets
Cash and cash equivalents	1,279.6		$ 1,360.2	1,279.6		2,210	$ 725.5
Restricted Cash and Cash Equivalents	1.3			1.3		0.3
Accounts receivable, net	517.9			517.9		565.4
Unbilled Receivables, Current	279			279		458.8
Inventory	816.1			816.1		786.8
Other current assets	251.9			251.9		93.5
Total current assets	3,124.9			3,124.9		4,098.1
Property, plant and equipment, net	1,683.6			1,683.6		1,773
Operating Lease, Right-of-Use Asset	37.3			37.3		41.2
Unbilled Receivable, Non Current	4.1			4.1		6.4
Pension assets	378.9			378.9		424.2
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	136.6			136.6		106.3
Goodwill	76			76		0
Intangible Assets, Net (Excluding Goodwill)	29.5			29.5		1.2
Investment in subsidiary	818.8			818.8		838.4
Deferred income taxes	226.1			226.1		147.6
Other assets	6,515.8			6,515.8		7,436.4
Total assets
Liabilities	503.5			503.5		977.1
Accounts payable	240.9			240.9		210
Accrued expenses	33.9			33.9		76.9
Profit sharing	333.5			333.5		48.4
Operating Lease, Liability, Current	4.9			4.9		5.3
Operating lease liabilities, short-term	20.1			20.1		21.6
Billings in Excess of Cost, Noncurrent	371.7			371.7		356.3
Billings in Excess of Cost, Current	100.9			100.9		158.3
Provision for Loss on Contracts	163.4			163.4		83.9
Forward loss provision, short-term	15.4			15.4		14.5
Deferred grant income liability — current	25.6			25.6		29.3
Other current liabilities	1,442.1			1,442.1		1,625.3
Long-term debt	2,650.2			2,650.2		2,974.7
Operating Lease, Liability, Noncurrent	32.7			32.7		36
Advance payments, long-term	325			325		333.3
Pension/OPEB obligation	47			47		35.7
Provision for Loss on Contacts, Non Current	303.8			303.8		163.5
Deferred grant income liability - non-current	8.9			8.9		9.2
Deferred revenue and other deferred credits	28.2			28.2		30.4
Deferred Tax Liabilities, Net, Noncurrent	0			0		0
Deferred income taxes	214.2			214.2		190.1
Total equity	1,092			1,092		1,681.9
Total liabilities and equity	6,515.8			6,515.8		7,436.4
Operating activities
Net cash (used in) operating activities				(634.9)	571.3
Investing activities
Purchase of property, plant and equipment				(53.4)	(94)
Payments for (Proceeds from) Other Investing Activities					0.1
Payments to Acquire Businesses, Net of Cash Acquired				(117.9)
Payments for (Proceeds from) Other Investing Activities				0.4
Net cash used in investing activities				(170.9)	(93.9)
Proceeds from (Repayments of) Other Debt				10
Proceeds from Lines of Credit					100
Proceeds from (Payments for) Other Financing Activities				0	0.8
Proceeds from Issuance of Senior Long-term Debt				(1,200)	250
Financing activities
Principal payments of debt				(21.2)	(7.8)
Repayments of Debt				(439.7)	(5.2)
Repayments of Lines of Credit				800	(100)
Collection on (repayment of) intercompany debt				(20.9)	56.1
Payment, Tax Withholding, Share-based Payment Arrangement				(14)	(12.1)
Proceeds (payments) from subsidiary for purchase of treasury stock				0.1	75
Proceeds from subsidiary (payments to Parent) to pay dividends				(14.4)	(37.6)
Payments of Dividends				0	0
Proceeds from Stock Plans				2.6	1.3
Net cash (used in ) provided by financing activities				(125.1)	170.5
Payments of Financing Costs				(27.6)
Payments for Repurchase of Common Stock					0
Effect of exchange rate changes on cash and cash equivalents				0.5	(13.2)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect				(930.4)	634.7
Cash and cash equivalents, beginning of period				2,193.3
Cash, cash equivalents, and restricted cash, end of period	1,258.7			1,258.7
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenues	56.7	96.4		224.2	342.3
Operating costs and expenses
Cost of sales	54.7	93.3		216.4	331.6
Selling, general and administrative	0.7	0.7		1.9	2.3
Restructuring Charges	0.2			0.5
Research and development	0.1	0.2		0.3	0.8
Gain (Loss) on Disposition of Property Plant Equipment	0			(3.7)
Total operating costs and expenses	55.7	94.2		222.8	334.7
Operating income	1	2.2		1.4	7.6
Interest expense and financing fee amortization	0			0
Other expense, net	(0.1)			(0.2)
Income (loss) before income taxes and equity in net loss of affiliates and subsidiaries	0.9	2.2		1.2	7.6
Income tax benefit (provision)	0.2	(0.5)		0.3	(1.8)
Income (loss) Before Equity In Net Income (Loss) Of Affiliates and Subsidiaries	0.7	1.7		0.9	5.8
Equity in net loss of affiliate	0			0
Equity in net income of subsidiaries	0			0
Net (loss) income	0.7	1.7		0.9	5.8
Total other comprehensive income (loss)	0			0
Comprehensive Income, Net of Tax, Attributable to Parent	0.7	$ 1.7		0.9	5.8
Assets
Restricted Cash and Cash Equivalents	0			0		0
Accounts receivable, net	66.1			66.1		50.5
Unbilled Receivables, Current	0			0		0
Inventory	161.8			161.8		136.8
Other current assets	0			0
Total current assets	227.9			227.9		187.3
Property, plant and equipment, net	273.8			273.8		306.3
Operating Lease, Right-of-Use Asset	7			7		7.5
Unbilled Receivable, Non Current	0			0		0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent						0
Goodwill	0			0		0
Intangible Assets, Net (Excluding Goodwill)	0			0		0
Other assets	508.7			508.7		501.1
Total assets
Liabilities	234.8			234.8		226.3
Accounts payable	1.7			1.7		0.8
Profit sharing	0.2			0.2		0.2
Operating Lease, Liability, Current	0.6			0.6		0.6
Billings in Excess of Cost, Noncurrent	0			0		0
Billings in Excess of Cost, Current	0			0
Provision for Loss on Contracts	0			0		0
Deferred grant income liability — current						2.1
Other current liabilities	237.3			237.3		230
Long-term debt	0.6			0.6		0.9
Operating Lease, Liability, Noncurrent	6.4			6.4		6.9
Provision for Loss on Contacts, Non Current	0			0		0
Deferred Tax Liabilities, Net, Noncurrent	0			0		0
Total equity	264.4			264.4		263.3
Total liabilities and equity	508.7			508.7		$ 501.1
Operating activities
Net cash (used in) operating activities				(16.2)	53.3
Investing activities
Purchase of property, plant and equipment				(1.3)	(7.7)
Payments for (Proceeds from) Other Investing Activities					0
Payments to Acquire Businesses, Net of Cash Acquired				0
Net cash used in investing activities				(1.3)	(7.7)
Proceeds from (Repayments of) Other Debt				0
Proceeds from Lines of Credit					0
Proceeds from (Payments for) Other Financing Activities				0	0
Proceeds from Issuance of Senior Long-term Debt				0
Financing activities
Principal payments of debt				(0.2)	(0.2)
Repayments of Debt				0	0
Repayments of Lines of Credit				0	0
Collection on (repayment of) intercompany debt				17.7	(45.4)
Payment, Tax Withholding, Share-based Payment Arrangement				0	0
Proceeds (payments) from subsidiary for purchase of treasury stock				0	0
Payments for Repurchase of Common Stock				0
Proceeds from subsidiary (payments to Parent) to pay dividends				0	0
Payments of Dividends				0	0
Proceeds from Stock Plans				0	0
Net cash (used in ) provided by financing activities				17.5	(45.6)
Payments of Financing Costs				0
Payments for Repurchase of Common Stock					$ 0
Cash, cash equivalents, and restricted cash, end of period	$ 0			$ 0

Uncategorized Items - spr-20201

Label	Element	Value
Accounting Standards Update and Change in Accounting Principle [Text Block]	us-gaap_NewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlock	In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-13, (“ASU 2016-13”), which requires the immediate recognition of management's estimates of current expected credit losses. ASU 2016-13 is effective for fiscal years and interim reporting periods within those years beginning after December 15, 2019. Early adoption is permitted after fiscal years beginning December 15, 2018. The Company adopted ASU 2016-13 as of January 1, 2020 by means of the modified retrospective method and required cumulative-effect adjustment to the opening retained earnings as of that date. The cumulative-effect adjustment to the opening retained earnings as of January 1, 2020 was not material. All credit losses in accordance with ASU 2016-13 were on receivables and/or contract assets arising from the Company’s contracts with customers including the cumulative-effect adjustment to the opening retained earnings. There is no significant impact to our operating results for the current period due to ASU 2016-13. In January 2017, the FASB issued Accounting Standards Update No. 2017-04, Intangibles-Goodwill and Other (Topic 350), Simplifying the Test for Goodwill Impairment (“ASU 2017-04”), which eliminates Step 2 of the goodwill impairment test and the qualitative assessment for any reporting unit with a zero or negative carrying amount. Under ASU 2017-04, an entity should perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount and should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. ASU 2017-04 is effective for annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. The adoption did not have an impact on our financial statements.