Balance Sheet Accounts - Schedule of Inventories (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	Nov. 30, 2015	Feb. 28, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Long-term contracts at average cost	$ 629.2	$ 543.5	$ 505.8
Progress payments	(459.8)	(388.5)	(349.6)
Total long-term contract inventories	169.4	155.0	156.2
Total other inventories	1.2	1.2	1.3
Inventories	$ 170.6	$ 156.2	$ 157.5	$ 161.5