v3.26.1
Investment Portfolio - Schedule of Investment Portfolio at Cost and Fair Value (Details) - USD ($)
$ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Schedule of Investments [Line Items]    
Amortized Cost $ 12,604.8 [1] $ 13,740.8 [2]
Fair Value $ 11,418.1 [1],[3] $ 13,008.6 [2],[4]
Percentage of Portfolio | Customer Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Portfolio 100.00% 100.00%
Senior Secured Loans—First Lien    
Schedule of Investments [Line Items]    
Amortized Cost $ 7,184.3 [1] $ 7,819.4 [2]
Fair Value $ 6,707.4 [1],[3] $ 7,523.4 [2],[4]
Senior Secured Loans—First Lien | Percentage of Portfolio | Customer Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Portfolio 58.70% 57.80%
Senior Secured Loans—Second Lien    
Schedule of Investments [Line Items]    
Amortized Cost $ 594.0 $ 598.0
Fair Value $ 440.0 $ 539.0
Senior Secured Loans—Second Lien | Percentage of Portfolio | Customer Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Portfolio 3.90% 4.20%
Other Senior Secured Debt    
Schedule of Investments [Line Items]    
Amortized Cost $ 43.0 $ 65.0
Fair Value $ 44.0 $ 55.0
Other Senior Secured Debt | Percentage of Portfolio | Customer Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Portfolio 0.40% 0.40%
Subordinated Debt    
Schedule of Investments [Line Items]    
Amortized Cost $ 107.2 [1] $ 122.0
Fair Value $ 99.8 [1],[3] $ 126.0
Subordinated Debt | Percentage of Portfolio | Customer Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Portfolio 0.90% 1.00%
Asset Based Finance    
Schedule of Investments [Line Items]    
Amortized Cost $ 1,626.0 [1] $ 1,830.9 [2]
Fair Value $ 1,436.1 [1],[3] $ 1,693.7 [2],[4]
Asset Based Finance | Percentage of Portfolio | Customer Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Portfolio 12.60% 13.00%
Credit Opportunities Partners JV, LLC    
Schedule of Investments [Line Items]    
Amortized Cost $ 1,984.1 [1] $ 2,201.9 [2]
Fair Value $ 1,648.7 [1],[3] $ 1,967.9 [2],[4]
Credit Opportunities Partners JV, LLC | Percentage of Portfolio | Customer Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Portfolio 14.40% 15.10%
Equity/Other    
Schedule of Investments [Line Items]    
Amortized Cost $ 1,067.0 $ 1,104.0
Fair Value $ 1,042.0 $ 1,104.0
Equity/Other | Percentage of Portfolio | Customer Concentration Risk    
Schedule of Investments [Line Items]    
Percentage of Portfolio 9.10% 8.50%
[1] Security may be an obligation of one or more entities affiliated with the named company.
[2] Security may be an obligation of one or more entities affiliated with the named company.
[3] See Note 8 for additional information regarding the fair value of the Company’s financial instruments.
[4] See Note 8 for additional information regarding the fair value of the Company’s financial instruments.