FAIR VALUE OF FINANCIAL INSTRUMENTS - Schedule of Fair Value Measurement Inputs and Valuation Techniques (Details) - Level 3 $ in Millions	Sep. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total investments	$ 20,977,000	$ 19,908
Yield analysis | First lien senior secured loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total investments	9,301,000	9,456
Yield analysis | Second lien senior secured loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total investments	3,711,000	4,432
Yield analysis | Senior subordinated loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total investments	1,043,000	889
Discounted cash flow analysis | Subordinated certificates of the SDLP
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total investments	1,121,000	987
Discounted cash flow analysis | Ivy Hill Asset Management, L.P.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total investments	1,958,000	936
EV market multiple analysis | Preferred equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total investments	2,052,000	1,561
EV market multiple analysis | Other equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total investments	$ 1,791,000	$ 1,647
Market yield | Yield analysis | Weighted Average | First lien senior secured loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	10.8	7.6
Market yield | Yield analysis | Weighted Average | Second lien senior secured loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	13.4	9.5
Market yield | Yield analysis | Weighted Average | Senior subordinated loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	12.1	11.5
Market yield | Yield analysis | Minimum | First lien senior secured loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	5.6	2
Market yield | Yield analysis | Minimum | Second lien senior secured loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	10	6.8
Market yield | Yield analysis | Minimum | Senior subordinated loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	7.1	7.1
Market yield | Yield analysis | Maximum | First lien senior secured loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	23.5	16.5
Market yield | Yield analysis | Maximum | Second lien senior secured loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	23.4	22.9
Market yield | Yield analysis | Maximum | Senior subordinated loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	14.6	27.8
Discount rate | Discounted cash flow analysis | Weighted Average | Subordinated certificates of the SDLP
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	12	9.3
Discount rate | Discounted cash flow analysis | Weighted Average | Ivy Hill Asset Management, L.P.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	13.4	16.3
Discount rate | Discounted cash flow analysis | Minimum | Subordinated certificates of the SDLP
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	11	8.8
Discount rate | Discounted cash flow analysis | Minimum | Ivy Hill Asset Management, L.P.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	11.1	9.9
Discount rate | Discounted cash flow analysis | Maximum | Subordinated certificates of the SDLP
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	13.4	9.7
Discount rate | Discounted cash flow analysis | Maximum | Ivy Hill Asset Management, L.P.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	23.7	27.9
EBITDA multiple | EV market multiple analysis | Weighted Average | Preferred equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	16.1	16.5
EBITDA multiple | EV market multiple analysis | Weighted Average | Other equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	15.2	14.9
EBITDA multiple | EV market multiple analysis | Minimum | Preferred equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	2.9	3.2
EBITDA multiple | EV market multiple analysis | Minimum | Other equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	2.3	4.9
EBITDA multiple | EV market multiple analysis | Maximum | Preferred equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	40.6	64.4
EBITDA multiple | EV market multiple analysis | Maximum | Other equity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Input	55.9	32.1