Summary of Significant Accounting Policies (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 27, 2018 USD ($)	Sep. 27, 2018 USD ($)
Disaggregation of Revenue [Line Items]
Costs Incurred in Anticipation of Contracts	$ 152.9	$ 152.9
Revenues	1,813.7	5,386.7
Boeing [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,465.5	4,262.2
Airbus [Member]
Disaggregation of Revenue [Line Items]
Revenues	263.8	869.0
Other Customer [Member]
Disaggregation of Revenue [Line Items]
Revenues	84.4	255.5
UNITED STATES
Disaggregation of Revenue [Line Items]
Revenues	1,534.0	4,460.8
UNITED KINGDOM
Disaggregation of Revenue [Line Items]
Revenues	184.4	574.1
Other International [Member]
Disaggregation of Revenue [Line Items]
Revenues	95.3	351.8
Total International [Member]
Disaggregation of Revenue [Line Items]
Revenues	279.7	925.9
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,456.7	4,212.6
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 357.0	$ 1,174.1