Balance Sheet Accounts and Supplemental Disclosures - Other Noncurrent Assets, net (Details) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Nov. 30, 2015 USD ($)	Nov. 30, 2014 USD ($)
Other Noncurrent Assets [Line Items]
Recoverable from the U.S. government for Rocketdyne Business integration costs	$ 3.3	$ 12.8
Deferred financing costs	2.1	3.4
Recoverable from the U.S. government for conditional asset retirement obligations	17.8	20.3
Grantor trust	10.3	16.6
Note receivable, net	9.0	9.0
Recoverable from the U.S. government for competitive improvement program obligations (see Note 10)	3.2	1.3
Other	6.8	5.1
Other noncurrent assets, net	81.6	90.2
Recoverable from the U.S. government for Rocketdyne Business integration costs	33.1	$ 22.8
Savings to restructuring cost ratio		2
Amortization of deferred financing costs	0.2	$ 2.0	$ 2.7	$ 3.6
UTC [Member]
Other Noncurrent Assets [Line Items]
Income tax receivable	7.9	10.8
Business Integration Costs [Member]
Other Noncurrent Assets [Line Items]
Recoverable from the U.S. government for Rocketdyne Business integration costs	$ 21.2	$ 10.9