Variable Interest Entities (Nonconsolidated VIEs) (Details) - USD ($) $ in Millions	Feb. 28, 2019	Nov. 30, 2018
Variable Interest Entity [Line Items]
Financial Statement Carrying Amount, Assets	$ 1,095.0	$ 746.4
Financial Statement Carrying Amount, Liabilities	3.8	0.0
Maximum Exposure to Loss	3,232.0	1,646.7
VIE Assets	15,644.1	12,382.4
CLOs
Variable Interest Entity [Line Items]
Financial Statement Carrying Amount, Assets	156.8	45.2
Financial Statement Carrying Amount, Liabilities	3.8	0.0
Maximum Exposure to Loss	1,939.5	571.4
VIE Assets	4,887.2	3,281.9
Consumer loan and other asset-backed vehicles
Variable Interest Entity [Line Items]
Financial Statement Carrying Amount, Assets	445.5	462.1
Financial Statement 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]
Financial Statement Carrying Amount, Assets	31.6	35.5
Financial Statement 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]
Financial Statement Carrying Amount, Assets	461.1	203.6
Financial Statement Carrying Amount, Liabilities	0.0	0.0
Maximum Exposure to Loss	471.5	214.7
VIE Assets	$ 7,175.1	$ 5,719.1