OFFSETTING ASSETS AND LIABILITIES - SCHEDULE OF ASSETS AND LIABILITIES SUBJECT TO MASTER NETTING ARRANGEMENTS (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Assets
Gross amount of securities borrowed	$ 0.6	$ 0.3
Gross amount offset on the unaudited condensed consolidated balance sheets	0.0	0.0
Amounts of assets presented on the unaudited condensed consolidated balance sheets	0.6	0.3
Securities borrowed	0.6	0.3
Security collateral received	(0.6)	(0.3)
Net amount	0.0	0.0
Liabilities
Gross amount of securities loaned	2,150.9	3,651.0
Gross amount of securities loaned offset on the unaudited condensed consolidated balance sheets	0.0	0.0
Amounts of liabilities presented on the unaudited condensed consolidated balance sheets	2,150.9	3,651.0
Securities loaned	2,150.9	3,651.0
Security collateral pledged	(1,976.7)	(3,426.8)
Net amount	$ 174.2	$ 224.2