INVESTMENTS - SCHEDULE OF INVESTMENTS IN OUR PORTFOLIO RATED BELOW-INVESTMENT GRADE WHICH HAVE BEEN CONTINUOUSLY IN AN UNREALIZED LOSS POSITION EXCEEDING 20% OF THE COST BASIS (Details) $ in Millions	Dec. 31, 2022 USD ($) issuer	Dec. 31, 2021 USD ($)
Debt Securities, Available-for-sale [Line Items]
Total, unrealized loss	$ (835.2)	$ (15.1)
Below-investment Grade
Debt Securities, Available-for-sale [Line Items]
Less than 6 months, Number of issuers | issuer	6
Less than 6 months	$ 47.5
Less than 6 months, Unrealized loss	(11.1)
Less than 6 months, Estimated fair value	$ 36.4
Greater than or equal to 6 months and less than 12 months, Number of issuers | issuer	5
Greater than or equal to 6 months and less than 12 months, Cost basis	$ 33.6
Greater than or equal to 6 months and less than 12 months, Unrealized loss	(10.3)
Greater than or equal to 6 months and less than 12 months, Estimated fair value	23.3
Total, cost basis	81.1
Total, unrealized loss	(21.4)
Total, estimated fair value	$ 59.7