Securitization Activities - Summary of Retained Interests in SPEs (Details) - USD ($) $ in Millions	Nov. 30, 2019	Nov. 30, 2018
Securitization Vehicles [Line Items]
Total RMBS securitization assets	$ 10,671.7	$ 13,633.5
Total CMBS securitization assets	1,374.8	2,027.6
Total Collateralized loan obligations	3,006.7	3,512.0
Consumer and other loans	1,149.3	604.1
U.S. government agency RMBS
Securitization Vehicles [Line Items]
Retained Interests	103.3	365.3
U.S. government agency CMBS
Securitization Vehicles [Line Items]
Retained Interests	45.8	185.6
CLOs
Securitization Vehicles [Line Items]
Retained Interests	58.4	20.9
Consumer and other loans
Securitization Vehicles [Line Items]
Retained Interests	$ 71.8	$ 48.9