Variable Interest Entities - Assets and Liabilities of Consolidated VIEs Prior to Consolidation (Detail) - USD ($) $ in Millions	May 31, 2019	Nov. 30, 2018
Securitization Vehicles
Variable Interest Entity [Line Items]
Assets	$ 1,266.9	$ 883.1
Liabilities	1,266.9	883.1
Secured financing included in inventory and eliminated		1.0
Securitization Vehicles | Cash
Variable Interest Entity [Line Items]
Assets	0.0	0.0
Securitization Vehicles | Financial instruments owned
Variable Interest Entity [Line Items]
Assets	0.0	0.0
Securitization Vehicles | Securities purchased under agreement to resell
Variable Interest Entity [Line Items]
Assets	1,266.9	883.1
Securitization Vehicles | Other secured financings
Variable Interest Entity [Line Items]
Liabilities	1,265.8	882.5
Securitization Vehicles | Other liabilities
Variable Interest Entity [Line Items]
Liabilities	1.1	0.6
Other
Variable Interest Entity [Line Items]
Assets	1.5	1.5
Liabilities	0.2	0.2
Other | Cash
Variable Interest Entity [Line Items]
Assets	1.1	1.1
Other | Financial instruments owned
Variable Interest Entity [Line Items]
Assets	0.4	0.4
Other | Securities purchased under agreement to resell
Variable Interest Entity [Line Items]
Assets	0.0	0.0
Other | Other secured financings
Variable Interest Entity [Line Items]
Liabilities	0.0	0.0
Other | Other liabilities
Variable Interest Entity [Line Items]
Liabilities	$ 0.2	$ 0.2