Changes in Estimates (Details) - USD ($) $ / shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 28, 2017	Sep. 29, 2016	Sep. 28, 2017	Sep. 29, 2016
Change In Estimate [Line Items]
Current Period Forward Loss Recorded			$ (359.6)
Cumulative Catch Up Adjustment			$ 28.7	$ 32.0
Changes in Contract Estimates, aggregate, Affecting earnings from Continuing Operations, per Share diluted	$ (30)	$ (30)	$ (1,750)	$ (440)
Change In Accounting Estimate, aggregate	$ (4.8)	$ (5.5)	$ (330.9)	$ (89.9)
Reduction In Previously Reported Forward-Loss				(121.9)
Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(2.8)	(4.3)
Change in Estimate on Loss Program [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting		(1.2)
Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(2.0)
Inventory Type B787 [Member]
Change In Estimate [Line Items]
Current Period Forward Loss Recorded	352.8
Fuselage Systems [Member]
Change In Estimate [Line Items]
Current Period Forward Loss Recorded			(238.5)
Cumulative Catch Up Adjustment			5.3	15.1
Reduction In Previously Reported Forward-Loss				(133.0)
Fuselage Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(2.4)	(1.9)
Fuselage Systems [Member] | Change in Estimate on Loss Program [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting		(1.6)
Fuselage Systems [Member] | Forward Loss [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(0.9)
Wing Systems [Member]
Change In Estimate [Line Items]
Cumulative Catch Up Adjustment			19.1	18.7
Reduction In Previously Reported Forward-Loss			(74.4)	5.1
Wing Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(2.8)	(0.8)
Wing Systems [Member] | Change in Estimate on Loss Program [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	(2.4)	0.9
Propulsion Systems [Member]
Change In Estimate [Line Items]
Current Period Forward Loss Recorded				6.0
Cumulative Catch Up Adjustment			4.3	$ (1.8)
Reduction In Previously Reported Forward-Loss			$ (46.7)
Change in Accounting Estimate - Contract Accounting	1.3
Propulsion Systems [Member] | Cumulative catch-up adjustment [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting	$ 2.4	(1.6)
Propulsion Systems [Member] | Change in Estimate on Loss Program [Member]
Change In Estimate [Line Items]
Change in Accounting Estimate - Contract Accounting		$ (0.5)