Balance Sheet Accounts and Supplemental Disclosures, (As Restated for fiscal 2014 and 2013) - Schedule of Other Noncurrent Assets, net (Details) - USD ($) $ in Millions	Nov. 30, 2015	Aug. 31, 2015	May. 31, 2015	Feb. 28, 2015	Nov. 30, 2014	Aug. 31, 2014	May. 31, 2014	Feb. 28, 2014
Other Noncurrent Assets [Line Items]
Deferred financing costs	$ 13.9				$ 18.5
Recoverable from the U.S. government for conditional asset retirement obligations	17.5				17.7
Grantor trust	10.7				11.2
Note receivable, net	9.0				0.0
Recoverable from the U.S. government for Competitive Improvement Program severance obligations	2.8				0.0
Other	9.4				11.3
Other noncurrent assets, net	85.7	$ 116.6	$ 115.5	$ 99.8	93.0	$ 94.1	$ 86.9	$ 80.0
UTC [Member]
Other Noncurrent Assets [Line Items]
Indemnification receivable from UTC, net	0.0				6.7
Business Integration Costs [Member]
Other Noncurrent Assets [Line Items]
Recoverable from the U.S. government for Rocketdyne Business integration costs	$ 22.4				$ 27.6