Acquisition (Details) - USD ($)	3 Months Ended		6 Months Ended		9 Months Ended
	Sep. 30, 2021	Oct. 01, 2020	Jul. 01, 2021	Jul. 02, 2020	Sep. 30, 2021	Oct. 01, 2020	Dec. 31, 2020
Business Acquisition [Line Items]
Revenues	$ 980,000,000.0	$ 806,300,000			$ 2,882,900,000	$ 2,528,200,000
Net Income (Loss) Attributable to Parent	(113,600,000)	$ (155,500,000)	$ (306,900,000)	$ (418,900,000)	(420,500,000)	$ (574,400,000)
Goodwill	$ 623,600,000				$ 623,600,000		$ 565,300,000
Earnings Per Share, Diluted	$ (1.09)	$ (1.50)			$ (4.04)	$ (5.53)
Restructuring Charges	$ 800,000	$ 19,500,000			$ 8,100,000	$ 68,400,000
Business Acquisition, Goodwill, Expected Tax Deductible Amount	24,800,000				24,800,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles					4,900,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities					38,500,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets					(2,300,000)
Business Combination Provisional Information Initial Accounting Incomplete Adjustment Other non-current liabilities					4,300,000
Retained Earnings [Member]
Business Acquisition [Line Items]
Net Income (Loss) Attributable to Parent	(113,600,000)	(155,500,000)	$ (306,900,000)	$ (418,900,000)
Asco [Member]
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs	100,000	17,300,000			100,000	17,300,000
Bombardier Acquisition
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Net Income (Loss)						(632,700,000)
Business Acquisition, Pro Forma Revenue						3,041,300,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	4,400,000				4,400,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	91,900,000				$ 91,900,000
Business Acquisition, Effective Date of Acquisition					Oct. 30, 2020
Business Combination, Consideration Transferred					$ 895,000,000
Business Combination, Reason for Business Combination					The acquisition is in line with the Company’s growth strategy of increasing Airbus content, developing a low-cost country footprint, and growing the Company’s aftermarket business.
Business Acquisition, Description of Acquired Entity					The Bombardier Acquired Businesses are global leaders in aerostructures and fabrication, delivering composite and metallic wing components, nacelles, fuselages and tail assemblies, along with high-value mechanical assemblies made out of aluminum, titanium and steel.
Business Acquisition, Transaction Costs	1,900,000	6,200,000			$ 1,900,000	$ 6,200,000
Goodwill	527,000,000.0				527,000,000.0		486,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory	251,600,000				251,600,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	11,400,000				11,400,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	373,600,000				373,600,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	193,000,000.0				193,000,000.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	11,700,000				11,700,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	1,492,300,000				1,492,300,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable	90,400,000				90,400,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	31,500,000				31,500,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other	317,700,000				317,700,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	1,217,300,000				1,217,300,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	275,000,000.0				275,000,000.0
Business Acquisition, Pro Forma Earnings Per Share, Diluted						$ (6.10)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets, Right of Use	27,700,000				27,700,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accrued payroll and employee benefits	113,800,000				113,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, forward loss provisions, short term	33,800,000				33,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Forward Loss Provisions	286,300,000				286,300,000
Business Combination, Recognized Identifiable Asset Acquired and Liability Assumed, Lease Obligation	27,500,000				27,500,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Retirement benefits	316,300,000				316,300,000
Business Combination, Consideration Transferred, Liabilities Incurred					316,000,000
Business Combination, Consideration Transferred, Other					304,000,000
Payments to Acquire Businesses, Gross					275,000,000
Applied Aerodynamics [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred					29,600,000
Business Acquisition, Transaction Costs	600,000				600,000
Goodwill	18,100,000				18,100,000
Technology-Based Intangible Assets [Member] | Bombardier Acquisition
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	62,000,000.0				$ 62,000,000.0
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life					15 years
Customer Relationships | Bombardier Acquisition
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	131,000,000.0				$ 131,000,000.0
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life					18 years
Customer Relationships | Applied Aerodynamics [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	3,000,000.0				$ 3,000,000.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	6,200,000				6,200,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets	2,300,000				2,300,000
Fuselage Systems [Member]
Business Acquisition [Line Items]
Revenues	481,200,000	421,100,000			1,410,500,000	$ 1,299,700,000
Goodwill	177,800,000				177,800,000		42,900,000
Restructuring Charges	200,000	6,600,000			2,900,000	39,100,000
Propulsion Systems [Member]
Business Acquisition [Line Items]
Revenues	247,800,000	170,800,000			716,200,000	565,600,000
Goodwill	415,100,000				415,100,000		33,100,000
Restructuring Charges	0.0	3,800,000			(200,000)	14,200,000
Wing Systems [Member]
Business Acquisition [Line Items]
Revenues	243,000,000.0	168,300,000			725,900,000	582,200,000
Goodwill	12,600,000				12,600,000		$ 2,500,000
Restructuring Charges	$ 600,000	$ 9,100,000			$ 5,400,000	$ 15,100,000