Unusual Items - Schedule of Unusual Items Expense (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2015
Unusual or Infrequent Item [Line Items]
(Gain) loss on legal matters and settlements (1)		$ (2.0)
Loss on debt	$ 0.0	0.0	$ 34.5	$ 1.9
Acquisition costs		1.0
Total unusual items	0.4	(1.0)	34.5	51.9
Aerospace and Defense
Unusual or Infrequent Item [Line Items]
(Gain) loss on legal matters and settlements (1)	0.4	(2.0)	0.0	50.0
Total unusual items	0.4	(2.0)	0.0	50.0
Corporate
Unusual or Infrequent Item [Line Items]
Loss on debt	0.0	0.0	34.4	1.9
Acquisition costs		1.0	0.0	0.0
Loss on bank amendment	0.0	0.0	0.1	0.0
Total unusual items	$ 0.0	$ 1.0	$ 34.5	$ 1.9