Variable Interest Entities - Assets and Liabilities of Consolidated VIEs Prior to Consolidation (Detail) - USD ($) $ in Millions	Feb. 29, 2016	Nov. 30, 2015
Securitization Vehicles [Member]
Variable Interest Entity [Line Items]
Assets	$ 958.7	$ 786.4
Liabilities	958.7	786.4
Securitization Vehicles [Member] | Cash [Member]
Variable Interest Entity [Line Items]
Assets	1.0	0.5
Securitization Vehicles [Member] | Financial Instruments Owned [Member]
Variable Interest Entity [Line Items]
Assets	79.1	68.3
Securitization Vehicles [Member] | Securities Purchased Under Agreement to Resell [Member]
Variable Interest Entity [Line Items]
Assets	878.1	717.3
Securitization Vehicles [Member] | Aircraft [Member]
Variable Interest Entity [Line Items]
Assets	0.0	0.0
Securitization Vehicles [Member] | Fees, Interest and Other Receivables [Member]
Variable Interest Entity [Line Items]
Assets	0.5	0.3
Securitization Vehicles [Member] | Other Secured Financings [Member]
Variable Interest Entity [Line Items]
Liabilities	956.6	785.0
Securitization Vehicles [Member] | Long-term Debt [Member]
Variable Interest Entity [Line Items]
Liabilities	0.0	0.0
Securitization Vehicles [Member] | Other Liabilities [Member]
Variable Interest Entity [Line Items]
Liabilities	2.1	1.4
Aircraft Financing Vehicle [Member]
Variable Interest Entity [Line Items]
Assets	27.3
Liabilities	24.4
Aircraft Financing Vehicle [Member] | Cash [Member]
Variable Interest Entity [Line Items]
Assets	0.0
Aircraft Financing Vehicle [Member] | Financial Instruments Owned [Member]
Variable Interest Entity [Line Items]
Assets	0.0
Aircraft Financing Vehicle [Member] | Securities Purchased Under Agreement to Resell [Member]
Variable Interest Entity [Line Items]
Assets	0.0
Aircraft Financing Vehicle [Member] | Aircraft [Member]
Variable Interest Entity [Line Items]
Assets	27.3
Aircraft Financing Vehicle [Member] | Fees, Interest and Other Receivables [Member]
Variable Interest Entity [Line Items]
Assets	0.0
Aircraft Financing Vehicle [Member] | Other Secured Financings [Member]
Variable Interest Entity [Line Items]
Liabilities	0.0
Aircraft Financing Vehicle [Member] | Long-term Debt [Member]
Variable Interest Entity [Line Items]
Liabilities	22.7
Aircraft Financing Vehicle [Member] | Other Liabilities [Member]
Variable Interest Entity [Line Items]
Liabilities	1.7
Other [Member]
Variable Interest Entity [Line Items]
Assets	2.3	2.3
Liabilities	0.2	0.3
Other [Member] | Cash [Member]
Variable Interest Entity [Line Items]
Assets	1.5	1.5
Other [Member] | Financial Instruments Owned [Member]
Variable Interest Entity [Line Items]
Assets	0.6	0.6
Other [Member] | Securities Purchased Under Agreement to Resell [Member]
Variable Interest Entity [Line Items]
Assets	0.0	0.0
Other [Member] | Aircraft [Member]
Variable Interest Entity [Line Items]
Assets	0.0	0.0
Other [Member] | Fees, Interest and Other Receivables [Member]
Variable Interest Entity [Line Items]
Assets	0.2	0.2
Other [Member] | Other Secured Financings [Member]
Variable Interest Entity [Line Items]
Liabilities	0.0	0.0
Other [Member] | Long-term Debt [Member]
Variable Interest Entity [Line Items]
Liabilities	0.0	0.0
Other [Member] | Other Liabilities [Member]
Variable Interest Entity [Line Items]
Liabilities	$ 0.2	$ 0.3