Variable Interest Entities - Assets and Liabilities of Consolidated VIEs Prior to Consolidation (Details) - USD ($) $ in Millions	Nov. 30, 2019	Nov. 30, 2018
Secured Funding Vehicles
Variable Interest Entity [Line Items]
Total assets	$ 2,467.3	$ 883.1
Total liabilities	2,467.3	883.1
Other
Variable Interest Entity [Line Items]
Total assets	1.5	1.5
Total liabilities	0.2	0.2
Cash | Secured Funding Vehicles
Variable Interest Entity [Line Items]
Total assets	0.0	0.0
Cash | Other
Variable Interest Entity [Line Items]
Total assets	1.2	1.1
Financial instruments owned | Secured Funding Vehicles
Variable Interest Entity [Line Items]
Total assets	0.0	0.0
Financial instruments owned | Other
Variable Interest Entity [Line Items]
Total assets	0.3	0.4
Securities purchased under agreements to resell | Secured Funding Vehicles
Variable Interest Entity [Line Items]
Total assets	2,467.3	883.1
Securities purchased under agreements to resell | Other
Variable Interest Entity [Line Items]
Total assets	0.0	0.0
Other secured financings
Variable Interest Entity [Line Items]
VIE liabilities, eliminated in consolidation		1.0
Other secured financings | Secured Funding Vehicles
Variable Interest Entity [Line Items]
Total liabilities	2,465.8	882.5
Other secured financings | Other
Variable Interest Entity [Line Items]
Total liabilities	0.0	0.0
Other liabilities
Variable Interest Entity [Line Items]
VIE liabilities, eliminated in consolidation	0.2	0.2
Other liabilities | Secured Funding Vehicles
Variable Interest Entity [Line Items]
Total liabilities	1.5	0.6
Other liabilities | Other
Variable Interest Entity [Line Items]
Total liabilities	$ 0.2	$ 0.2