Variable Interest Entities - Variable Interests in Non-Consolidated Variable Interest Entities (Detail) (Variable Interest Entity Not Primary Beneficiary [Member], USD $) In Millions, unless otherwise specified	Feb. 28, 2015	Nov. 30, 2014
Variable Interest Entity [Line Items]
Carrying Amount, Assets	$ 280.4	$ 360.2
Carrying Amount, Liabilities	0	0
Maximum exposure to loss in non-consolidated VIEs	1,631.0	1,795.2
Size of the variable interest entity measured by total assets	8,807.2	8,747.4
Collateralized loan obligations [Member]
Variable Interest Entity [Line Items]
Carrying Amount, Assets	75.4	134.0
Carrying Amount, Liabilities	0	0
Maximum exposure to loss in non-consolidated VIEs	817.9	926.9
Size of the variable interest entity measured by total assets	8,125.2	7,737.1
Consumer Loan Financing Vehicles [Member]
Variable Interest Entity [Line Items]
Carrying Amount, Assets	175.3	170.6
Carrying Amount, Liabilities	0	0
Maximum exposure to loss in non-consolidated VIEs	758.8	797.8
Size of the variable interest entity measured by total assets	411.6	485.2
Asset management vehicle [Member]
Variable Interest Entity [Line Items]
Carrying Amount, Assets	6.0	11.3
Carrying Amount, Liabilities	0	0
Maximum exposure to loss in non-consolidated VIEs	6.0	11.3
Size of the variable interest entity measured by total assets	199.6	432.3
Private equity vehicles [Member]
Variable Interest Entity [Line Items]
Carrying Amount, Assets	23.7	44.3
Carrying Amount, Liabilities	0	0
Maximum exposure to loss in non-consolidated VIEs	48.3	59.2
Size of the variable interest entity measured by total assets	$ 70.8	$ 92.8