Revenue Disaggregation and Outstanding Performance Obligations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Oct. 01, 2020	Jul. 02, 2020	Apr. 02, 2020	Dec. 31, 2019	Sep. 26, 2019	Jun. 27, 2019	Mar. 28, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues	$ 876.6	$ 806.3	$ 644.6	$ 1,077.3	$ 1,959.3	$ 1,919.9	$ 2,016.1	$ 1,967.8	$ 3,404.8	$ 7,863.1	$ 7,222.0
Expected to be satisfied in next fiscal year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	2,726.2								2,726.2
Expected to be satisfied in fiscal year +2
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	3,661.8								3,661.8
Expected to be satisfied in fiscal year +3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	4,406.4								4,406.4
Expected to be satisfied in fiscal year +4 and thereafter
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 3,206.8								3,206.8
Transferred over Time [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues									2,188.4	5,963.5
Transferred at Point in Time [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues									1,216.4	1,899.6
Location United States [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues									2,637.6	6,566.3
Location United Kingdom [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues									433.5	771.9
Other Countries [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues									333.7	524.9	$ 491.6
Disaggregation of revenue, total international locations [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues									767.2	1,296.8
Boeing - all programs [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues									2,043.8	6,237.2
Airbus [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues									773.3	1,250.6
Other Customer [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenues									$ 587.7	$ 375.3