FAIR VALUE OF FINANCIAL INSTRUMENTS- Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Cash and cash equivalents	$ 303.0	$ 372.0
Restricted cash	34.0	114.0
Total investments	21,779.8	20,009.5
Derivatives	(21.0)	(12.0)
Total unfunded capital commitments	57.0	20.0
Total
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total investments	21,775.0	20,004.0
Level 1
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Cash and cash equivalents	303.0	372.0
Restricted cash	34.0	114.0
Total investments	54.0	0.0
Derivatives	0.0	0.0
Total unfunded capital commitments	0.0	0.0
Level 2
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Cash and cash equivalents	0.0	0.0
Restricted cash	0.0	0.0
Total investments	360.0	96.0
Derivatives	(21.0)	(12.0)
Total unfunded capital commitments	0.0	0.0
Level 3
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Cash and cash equivalents	0.0	0.0
Restricted cash	0.0	0.0
Total investments	21,361.0	19,908.0
Derivatives	0.0	0.0
Total unfunded capital commitments	57.0	20.0
Investments measured at net asset value
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total investments	$ 5.0	$ 5.0