Changes in Estimates (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 26, 2019	Jun. 27, 2019	Mar. 28, 2019	Dec. 31, 2018	Sep. 27, 2018	Jun. 28, 2018	Mar. 29, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change In Estimate [Line Items]
Change In Accounting Estimate, aggregate, affecting earnings from continuing operations	$ 55.2	$ 41.8	$ 10.9	$ 0.5	$ 3.5	$ 13.5	$ 24.9	$ 22.6	$ (65.5)	$ 0.1	$ (296.1)
Changes in Accounting Estimates - Contract Accounting, aggregate, Affecting earnings from Continuing Operations, per Share diluted									$ (0.50)	$ 0.00	$ (1.58)
Change in Accounting Estimate - Contract Accounting									$ (63.5)	$ 3.9	$ (327.3)
Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting									(2.0)	(3.8)	31.2
Wing Systems [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting									(10.5)
Wing Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting									0.5	1.7	23.4
Wing Systems [Member] | Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting										1.2	(63.9)
Fuselage Systems [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting									(37.9)	3.4	(223.2)
Fuselage Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting									(1.3)	(5.3)	4.0
Propulsion Systems [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting									(15.1)	(0.7)	(40.2)
Propulsion Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting									(1.2)	$ (0.2)	$ 3.8
B787 [Member] | Change in Estimate on Loss Program [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting									41.1
B787 [Member] | Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting			$ 352.8
Airbus350 XWB [Member] | Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting									$ 19.4