Securitization Activities - Summary of Retained Interests in SPEs (Detail) - USD ($) $ in Millions	May. 31, 2015	Nov. 30, 2014
Securitization Vehicles [Line Items]
Total RMBS securitization assets	$ 10,986.6	$ 19,196.9
Total CMBS securitization assets	3,022.9	5,848.5
Total Collateralized loan obligations	4,677.1	4,511.8
U.S. government agency residential mortgage-backed securities [Member]
Securitization Vehicles [Line Items]
Fair Value of Securitizations Initially Retained	139.5	226.9
U.S. government agency commercial mortgage-backed securities [Member]
Securitization Vehicles [Line Items]
Fair Value of Securitizations Initially Retained	85.8	204.7
Collateralized loan obligations [Member]
Securitization Vehicles [Line Items]
Fair Value of Securitizations Initially Retained	$ 61.6	$ 108.4