Fair Value Measurements - Fair Value Hierarchy of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	$ 68,419,777	$ 50,743,911
Level 1, Level 2, and Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	66,505,366	48,582,386
Level 1, Level 2, and Level 3 | First lien debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	61,455,274	45,534,013
Level 1, Level 2, and Level 3 | Second lien debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	2,723,460	1,736,088
Level 1, Level 2, and Level 3 | Unsecured debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	177,801	18,171
Level 1, Level 2, and Level 3 | Structured finance obligations - debt instruments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	590,509
Level 1, Level 2, and Level 3 | Structured finance obligations - equity instruments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	141,139
Level 1, Level 2, and Level 3 | Equity and other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	1,417,183
Level 1, Level 2, and Level 3 | Structured finance obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		436,863
Level 1, Level 2, and Level 3 | Equity investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		857,251
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	66,050	0
Level 1 | First lien debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Level 1 | Second lien debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Level 1 | Unsecured debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0	0
Level 1 | Structured finance obligations - debt instruments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0
Level 1 | Structured finance obligations - equity instruments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0
Level 1 | Equity and other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	66,050
Level 1 | Structured finance obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		0
Level 1 | Equity investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	4,956,506	5,077,463
Level 2 | First lien debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	4,300,303	4,197,276
Level 2 | Second lien debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	635,141	809,223
Level 2 | Unsecured debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	20,686	0
Level 2 | Structured finance obligations - debt instruments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0
Level 2 | Structured finance obligations - equity instruments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	0
Level 2 | Equity and other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	376
Level 2 | Structured finance obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		70,964
Level 2 | Equity investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		0
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	61,482,810	43,504,923
Level 3 | First lien debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	57,154,971	41,336,737
Level 3 | Second lien debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	2,088,319	926,865
Level 3 | Unsecured debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	157,115	18,171
Level 3 | Structured finance obligations - debt instruments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	590,509
Level 3 | Structured finance obligations - equity instruments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	141,139
Level 3 | Equity and other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	1,350,757
Level 3 | Structured finance obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		365,899
Level 3 | Equity investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	1,350,757	857,251
NAV
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	$ 1,914,411	$ 2,161,525