Securitization Activities - Summary of Retained Interests in SPEs (Details) - USD ($) $ in Millions	Nov. 30, 2021	Nov. 30, 2020
Securitization Vehicles [Line Items]
Total RMBS securitization assets	$ 330.2	$ 562.5
Total CMBS securitization assets	2,201.8	2,461.2
Total collateralized loan obligations	3,382.3	3,345.5
Consumer and other loans	2,271.4	1,290.6
U.S. government agency RMBS
Securitization Vehicles [Line Items]
Retained Interests	4.9	7.8
U.S. government agency CMBS
Securitization Vehicles [Line Items]
Retained Interests	69.2	205.2
CLOs
Securitization Vehicles [Line Items]
Retained Interests	31.0	39.5
Consumer and other loans
Securitization Vehicles [Line Items]
Retained Interests	$ 136.4	$ 56.6