Changes in Estimates (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Oct. 01, 2020	Sep. 30, 2021	Oct. 01, 2020
Change In Estimate [Line Items]
Changes in Contract Estimates, aggregate, Affecting earnings from Continuing Operations, per Share diluted	$ (0.69)	$ (0.77)	$ (1.86)	$ (2.33)
Change In Accounting Estimate, aggregate	$ (73.2)	$ (123.8)	$ (197.5)	$ (372.8)
Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(2.8)	4.6	(2.5)	(30.6)
Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(70.4)	(128.4)	(195.0)	(342.2)
Fuselage Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(1.6)	8.8	4.9	(18.9)
Fuselage Systems [Member] | Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(49.9)	(92.0)	(140.7)	(260.3)
Wing Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(2.9)	0.4	(5.6)	(3.1)
Wing Systems [Member] | Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(14.6)	(21.5)	(35.1)	(47.7)
Propulsion Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	1.6	(4.6)	(2.0)	(8.6)
Propulsion Systems [Member] | Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(5.9)	(14.9)	(19.2)	(34.2)
Other Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	$ 0.1	$ 0.0	$ 0.2	$ 0.0