NON-TRADED INVESTMENTS (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Variable Interest Entity [Line Items]
Assets	$ 20,494.5	$ 20,496.2	$ 21,186.1
VIEs
Variable Interest Entity [Line Items]
Assets	192.2		210.1
Liabilities	$ 156.5		$ 165.6