Variable Interest Entities (Schedule of Nonconsolidated VIEs) (Details) - USD ($) $ in Millions	Feb. 29, 2020	Nov. 30, 2019
Variable Interest Entity [Line Items]
Nonconsolidated VIEs, assets carrying amount	$ 1,216.9	$ 1,107.9
Nonconsolidated VIEs, liabilities carrying amount	0.6	0.6
Maximum Exposure to Loss	1,594.0	1,796.3
VIE Assets	20,069.3	19,526.2
CLOs
Variable Interest Entity [Line Items]
Nonconsolidated VIEs, assets carrying amount	70.2	152.6
Nonconsolidated VIEs, liabilities carrying amount	0.6	0.6
Maximum Exposure to Loss	117.5	505.3
VIE Assets	6,631.0	7,845.0
Consumer loan and other asset-backed vehicles
Variable Interest Entity [Line Items]
Nonconsolidated VIEs, assets carrying amount	279.8	358.3
Nonconsolidated VIEs, liabilities carrying amount	0.0	0.0
Maximum Exposure to Loss	407.8	490.6
VIE Assets	2,596.7	2,354.8
Related party private equity vehicles
Variable Interest Entity [Line Items]
Nonconsolidated VIEs, assets carrying amount	23.8	23.0
Nonconsolidated VIEs, liabilities carrying amount	0.0	0.0
Maximum Exposure to Loss	34.9	34.3
VIE Assets	67.0	71.4
Other investment vehicles
Variable Interest Entity [Line Items]
Nonconsolidated VIEs, assets carrying amount	843.1	574.0
Nonconsolidated VIEs, liabilities carrying amount	0.0	0.0
Maximum Exposure to Loss	1,033.8	766.1
VIE Assets	$ 10,774.6	$ 9,255.0