Pension and Other Post Retirement Plans (Details 4) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year, Description	Required U.S. pension contributions under Employee Retirement Income Security Act (ERISA) regulations are expected to be zero in 2021 and discretionary contributions are not expected in 2021. SERP and post-retirement medical plan contributions in 2021 are expected to be $10.3. Expected contributions to the U.K. Prestwick plan for 2021 are $1.8. Expected contributions to the U.K. (Belfast) plans for 2021 are $180.2, including a one-time contribution of £100 agreed as part of the acquisition of the Short Brothers plc.
Pension Plan [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	$ 41.3
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	43.6
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	45.4
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	47.6
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	49.5
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	269.5
Pension Plan [Member] | UNITED KINGDOM
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	0.9
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	0.9
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	0.9
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	0.9
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	1.0
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	5.1
Pension Plan [Member] | Belfast
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	61.1
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	62.2
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	63.2
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	64.3
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	65.4
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	344.2
Other Benefits [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	10.3
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	9.5
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	8.0
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	5.7
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	3.9
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	11.8
Other Benefits [Member] | Belfast
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	0.1
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	0.1
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	0.1
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	0.1
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	0.1
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	$ 5.0