v3.26.1
Fair Value of Financial Instruments - Fair Value Measurements of Cash and Cash Equivalents and Investments (Details) - USD ($)
Dec. 31, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments $ 21,508,598,400 $ 11,549,149,400
Unfunded revolving and delayed draw loan commitments (10,885,000) (5,572,000)
Derivatives (137,150,000) (4,650,000)
Foreign currency forward contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives (22,867,000) 8,506,000
Interest rate swaps    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 58,008,000 (28,598,000)
First lien senior secured loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 17,160,266,000 10,130,307,000
Second lien senior secured loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 429,160,000 158,500,000
Senior subordinated loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 1,068,842,000 213,500,000
Corporate bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 99,063,000 65,312,000
Collateralized loan obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 1,051,264,000 370,985,000
Commercial mortgage-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 99,962,000 29,161,000
Private asset-backed investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 300,947,000 208,357,000
Investments in joint ventures    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 391,000,000  
Preferred equity    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 317,476,000 122,570,000
Other equity    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 489,521,000 247,144,000
Total    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 21,407,501,000 11,545,836,000
Total | Corporate bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments   65,312,000
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 6,909,693,000 5,610,338,000
Level 2 | Foreign currency forward contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives (22,867,000) 8,506,000
Level 2 | Interest rate swaps    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivatives 58,008,000 (28,598,000)
Level 2 | First lien senior secured loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 6,617,396,000 5,481,780,000
Level 2 | Second lien senior secured loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 287,211,000 128,558,000
Level 2 | Senior subordinated loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 5,086,000  
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 14,497,808,000 5,935,498,000
Unfunded revolving and delayed draw loan commitments (10,885,000) (5,572,000)
Level 3 | First lien senior secured loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 10,542,870,000 4,648,527,000
Level 3 | Second lien senior secured loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 141,949,000 29,942,000
Level 3 | Senior subordinated loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 1,063,756,000 213,500,000
Level 3 | Corporate bonds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 99,063,000 65,312,000
Level 3 | Collateralized loan obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 1,051,264,000 370,985,000
Level 3 | Commercial mortgage-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 99,962,000 29,161,000
Level 3 | Private asset-backed investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 300,947,000 208,357,000
Level 3 | Investments in joint ventures    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 391,000,000  
Level 3 | Preferred equity    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 317,476,000 122,570,000
Level 3 | Other equity    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 489,521,000 247,144,000
Measured at NAV    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments $ 101,097,000 $ 3,313,000