Securitization Activities - Summary of Retained Interests in SPEs (Detail) - USD ($) $ in Millions	Aug. 31, 2015	Nov. 30, 2014
Securitization Vehicles [Line Items]
Total RMBS securitization assets	$ 11,480.4	$ 19,196.9
Total CMBS securitization assets	2,831.3	5,848.5
Total Collateralized loan obligations	3,731.7	4,511.8
U.S. government agency residential mortgage-backed securities [Member]
Securitization Vehicles [Line Items]
Fair Value of Securitizations Initially Retained	162.0	226.9
U.S. government agency commercial mortgage-backed securities [Member]
Securitization Vehicles [Line Items]
Fair Value of Securitizations Initially Retained	213.2	204.7
Collateralized loan obligations [Member]
Securitization Vehicles [Line Items]
Fair Value of Securitizations Initially Retained	$ 52.3	$ 108.4