INVESTMENTS - Senior Direct Lending Program (Details) $ in Millions	Dec. 31, 2022 USD ($) loan	Dec. 31, 2021 USD ($) loan
Schedule of Investments [Line Items]
Amortized Cost	$ 22,043.0	$ 19,810.0
Fair Value	21,779.8	20,009.5
Subordinated certificates of the SDLP
Schedule of Investments [Line Items]
Amortized Cost	1,274.0	987.0
Fair Value	$ 1,249.0	$ 987.0
Yield on investment, at cost	13.50%	13.50%
Yield on investment, at fair value	13.80%	13.50%
Number of loans on non-accrual status | loan	1	0
Subordinated certificates of the SDLP | London Interbank Offered Rate (LIBOR)
Schedule of Investments [Line Items]
Interest rate, spread	8.00%
Subordinated certificates of the SDLP | Ares Capital Corporation
Schedule of Investments [Line Items]
Ownership percentage of outstanding SDLP Certificates	87.50%	87.50%
Subordinated certificates of the SDLP | Client of Varagon
Schedule of Investments [Line Items]
Ownership percentage of outstanding SDLP Certificates	12.50%	12.50%
Senior Direct Lending Program
Schedule of Investments [Line Items]
Amount available for commitment	$ 450.0
Capital available to the SDLP	6,150.0	$ 6,150.0
Amortized Cost	5,166.0	4,193.0
Fair Value	4,958.0	4,127.0
Senior Direct Lending Program | Ares Capital Corporation
Schedule of Investments [Line Items]
Capital available to the SDLP	$ 1,444.0	$ 1,444.0