Variable Interest Entities (Nonconsolidated VIEs) (Details) - USD ($) $ in Millions	May 31, 2019	Nov. 30, 2018
Variable Interest Entity [Line Items]
Financial Statement Carrying Amount, Assets	$ 1,080.4	$ 746.4
Financial Statement Carrying Amount, Liabilities	0.6	0.0
Maximum Exposure to Loss	1,976.6	1,646.7
VIE Assets	19,539.0	12,382.4
CLOs
Variable Interest Entity [Line Items]
Financial Statement Carrying Amount, Assets	114.9	45.2
Financial Statement Carrying Amount, Liabilities	0.6	0.0
Maximum Exposure to Loss	830.7	571.4
VIE Assets	7,980.2	3,281.9
Consumer loan and other asset-backed vehicles
Variable Interest Entity [Line Items]
Financial Statement Carrying Amount, Assets	427.3	462.1
Financial Statement Carrying Amount, Liabilities	0.0	0.0
Maximum Exposure to Loss	570.1	807.1
VIE Assets	3,322.6	3,273.1
Related party private equity vehicles
Variable Interest Entity [Line Items]
Financial Statement Carrying Amount, Assets	31.2	35.5
Financial Statement Carrying Amount, Liabilities	0.0	0.0
Maximum Exposure to Loss	49.0	53.5
VIE Assets	92.0	108.3
Other investment vehicles
Variable Interest Entity [Line Items]
Financial Statement Carrying Amount, Assets	507.0	203.6
Financial Statement Carrying Amount, Liabilities	0.0	0.0
Maximum Exposure to Loss	526.8	214.7
VIE Assets	$ 8,144.2	$ 5,719.1