Securitization Activities - Summary of Retained Interests in SPEs (Details) - USD ($) $ in Millions	May 31, 2020	Nov. 30, 2019
Debt and Equity Securities, FV-NI [Line Items]
Total RMBS securitization assets	$ 1,028.5	$ 10,671.7
Total CMBS securitization assets	672.3	1,374.8
Total Collateralized loan obligations	1,468.1	3,006.7
Consumer and other loans	707.6	1,149.3
U.S. government agency RMBS
Debt and Equity Securities, FV-NI [Line Items]
Retained Interests	55.6	103.3
U.S. government agency CMBS
Debt and Equity Securities, FV-NI [Line Items]
Retained Interests	55.2	45.8
CLOs
Debt and Equity Securities, FV-NI [Line Items]
Retained Interests	121.6	58.4
Consumer and other loans
Debt and Equity Securities, FV-NI [Line Items]
Retained Interests	$ 67.5	$ 71.8