Segment Information (Details)	3 Months Ended		6 Months Ended
	Jul. 01, 2021 USD ($)	Jul. 02, 2020 USD ($)	Jul. 01, 2021 USD ($) segment	Jul. 02, 2020 USD ($)
Segment Reporting Information [Line Items]
Restructuring Charges	$ 5,200,000	$ 6,300,000	$ 7,300,000	$ 48,900,000
Excess Capacity Costs- B737MAX and A320 Production Schedules	47,500,000		115,100,000
Abnormal Costs- COVID19 production suspension	2,400,000		4,500,000
Cost of Goods and Services Sold	1,014,400,000	925,100,000	1,973,200,000	2,037,600,000
Gain (Loss) on Disposition of Property Plant Equipment	0	(22,900,000)	0	(22,900,000)
Segment Revenues
Segment Revenues	1,002,100,000	644,600,000	1,902,900,000	1,721,900,000
Segment Operating Income
Business Segment Operating Income	(18,300,000)	(303,300,000)	(79,100,000)	(379,600,000)
Segment Information Unallocated Corporate Selling General And Administrative	(66,900,000)	(49,000,000.0)	(124,500,000)	(126,400,000)
Segment Information Unallocated Research And Development	(13,300,000)	(8,300,000)	(21,500,000)	(20,600,000)
Segment Information Unallocated Cost Of Sales	800,000	(6,400,000)	1,500,000	(7,900,000)
Operating loss	(97,700,000)	(367,000,000.0)	$ (223,600,000)	(534,500,000)
Segment Reporting Information, Additional Information [Abstract]
Number Of Principal Segments | segment			3
Fuselage Systems [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	900,000	2,400,000	$ 2,700,000	32,500,000
Excess Capacity Costs- B737MAX and A320 Production Schedules	27,600,000	50,600,000	70,200,000	101,800,000
Abnormal Costs- COVID19 production suspension	1,400,000	11,200,000	2,100,000	26,500,000
Gain (Loss) on Disposition of Property Plant Equipment		22,500,000
Segment Revenues
Segment Revenues	492,200,000	327,100,000	929,300,000	878,600,000
Segment Operating Income
Business Segment Operating Income	(31,800,000)	(251,500,000)	(91,600,000)	(337,900,000)
Propulsion Systems [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	0.0	1,600,000	(200,000)	10,400,000
Excess Capacity Costs- B737MAX and A320 Production Schedules	7,100,000	17,500,000	14,300,000	33,300,000
Abnormal Costs- COVID19 production suspension	300,000	4,000,000.0	400,000	10,200,000
Segment Revenues
Segment Revenues	241,900,000	169,600,000	468,400,000	394,800,000
Segment Operating Income
Business Segment Operating Income	28,200,000	(17,300,000)	44,900,000	(22,600,000)
Wing Systems [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	4,300,000	2,300,000	4,800,000	6,000,000.0
Excess Capacity Costs- B737MAX and A320 Production Schedules	12,800,000	14,700,000	30,600,000	21,100,000
Abnormal Costs- COVID19 production suspension	700,000	4,100,000	2,000,000.0	8,000,000.0
Gain (Loss) on Disposition of Property Plant Equipment		400,000
Segment Revenues
Segment Revenues	259,300,000	122,500,000	482,900,000	413,900,000
Segment Operating Income
Business Segment Operating Income	(16,200,000)	(42,500,000)	(35,100,000)	(28,900,000)
Other Systems [Member]
Segment Revenues
Segment Revenues	8,700,000	25,400,000	22,300,000	34,600,000
Segment Operating Income
Business Segment Operating Income	$ 1,500,000	$ 8,000,000.0	$ 2,700,000	$ 9,800,000