Variable Interest Entities - Variable Interests in Non-Consolidated Variable Interest Entities (Details) - Nonconsolidated VIEs - USD ($) $ in Millions	Aug. 31, 2019	Nov. 30, 2018
Variable Interest Entity [Line Items]
Carrying Amount, Assets	$ 1,076.9	$ 634.7
Carrying Amount, Liabilities	0.9	0.0
Maximum Exposure to Loss	1,926.5	1,528.0
VIE Assets	17,544.6	10,028.4
CLOs
Variable Interest Entity [Line Items]
Carrying Amount, Assets	124.0	42.1
Carrying Amount, Liabilities	0.9	0.0
Maximum Exposure to Loss	801.5	568.3
VIE Assets	7,889.6	3,088.9
Consumer loan and other asset-backed vehicles
Variable Interest Entity [Line Items]
Carrying Amount, Assets	525.1	462.1
Carrying Amount, Liabilities	0.0	0.0
Maximum Exposure to Loss	668.8	807.1
VIE Assets	3,020.6	3,273.1
Related party private equity vehicles
Variable Interest Entity [Line Items]
Carrying Amount, Assets	28.7	35.5
Carrying Amount, Liabilities	0.0	0.0
Maximum Exposure to Loss	46.2	53.5
VIE Assets	83.7	108.3
Other investment vehicles
Variable Interest Entity [Line Items]
Carrying Amount, Assets	399.1	95.0
Carrying Amount, Liabilities	0.0	0.0
Maximum Exposure to Loss	410.0	99.1
VIE Assets	$ 6,550.7	$ 3,558.1