Balance Sheet Accounts - Schedule of Other Noncurrent Assets, net (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	Nov. 30, 2015	Feb. 28, 2015
Other Noncurrent Assets [Line Items]
Deferred financing costs	$ 2.0	$ 2.1	$ 2.3
Recoverable from the U.S. government for Competitive Improvement Program severance obligations	1.7	3.2	2.8
Recoverable from the U.S. government for conditional asset retirement obligations	18.5	17.8	17.5
Grantor trusts	10.2	10.3	10.7
Notes receivable, net	9.0	9.0	9.0
Other	11.1	10.1	9.4
Other noncurrent assets, net	79.1	81.6	82.0	$ 84.9
UTC [Member]
Other Noncurrent Assets [Line Items]
Income taxes receivable	7.9	7.9	7.9
Business Integration Costs [Member]
Other Noncurrent Assets [Line Items]
Recoverable from the U.S. government for Rocketdyne Business integration costs	$ 18.7	$ 21.2	$ 22.4