Variable Interest Entities - Variable Interests in Non-Consolidated Variable Interest Entities (Detail) - Nonconsolidated VIEs - USD ($) $ in Millions	Feb. 28, 2019	Nov. 30, 2018
Variable Interest Entity [Line Items]
Carrying Amount, Assets	$ 984.7	$ 634.7
Carrying Amount, Liabilities	3.8	0.0
Maximum Exposure to Loss	3,114.6	1,528.0
VIE Assets	13,410.7	10,028.4
CLOs
Variable Interest Entity [Line Items]
Carrying Amount, Assets	153.7	42.1
Carrying Amount, Liabilities	3.8	0.0
Maximum Exposure to Loss	1,936.4	568.3
VIE Assets	4,713.4	3,088.9
Consumer loan and other asset-backed vehicles
Variable Interest Entity [Line Items]
Carrying Amount, Assets	445.5	462.1
Carrying Amount, Liabilities	0.0	0.0
Maximum Exposure to Loss	771.6	807.1
VIE Assets	3,491.0	3,273.1
Related party private equity vehicles
Variable Interest Entity [Line Items]
Carrying Amount, Assets	31.6	35.5
Carrying Amount, Liabilities	0.0	0.0
Maximum Exposure to Loss	49.4	53.5
VIE Assets	90.8	108.3
Other investment vehicles
Variable Interest Entity [Line Items]
Carrying Amount, Assets	353.9	95.0
Carrying Amount, Liabilities	0.0	0.0
Maximum Exposure to Loss	357.2	99.1
VIE Assets	$ 5,115.5	$ 3,558.1