v3.25.1
Investment Portfolio - Narrative (Details)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2025
USD ($)
company
Mar. 31, 2024
USD ($)
Dec. 31, 2024
USD ($)
company
Schedule of Investments [Line Items]      
Amount funded to joint venture $ 2,140.0    
Net realized gain (loss) on investments: (18.0) $ (243.0)  
Receivable for investments sold and repaid 65.0   $ 186.0
Credit Opportunities Partners JV, LLC      
Schedule of Investments [Line Items]      
Aggregate credit opportunities partners 2,800.0    
Cost basis of investments sold 282.3    
Proceeds from sale of investments 289.7    
Net realized gain (loss) on investments: 7.4    
Receivable for investments sold and repaid $ 25.8    
Credit opportunities partners JV, LLC, entitled to a fee percentage 0.25%    
Administrative services $ 2.3 2.4  
FS KKR Capital Corp.      
Schedule of Investments [Line Items]      
Contributed capital to committed capital ratio 87.50%    
Joint venture voting control, percentage 50.00%    
Amount funded to joint venture $ 1,872.5    
SCRS      
Schedule of Investments [Line Items]      
Contributed capital to committed capital ratio 12.50%    
Joint venture voting control, percentage 50.00%    
Unfunded Debt Securities      
Schedule of Investments [Line Items]      
Unfunded commitments $ 1,636.5   1,534.1
Unfunded Equity/Other Commitments      
Schedule of Investments [Line Items]      
Unfunded commitments $ 394.8   387.1
Partnership Interest      
Schedule of Investments [Line Items]      
Unfunded commitments     $ 735.2
Controlled/affiliated      
Schedule of Investments [Line Items]      
Number of investments in portfolio companies | company 32   31
Net realized gain (loss) on investments: $ 12.5 (8.0) $ 23.2
Non-controlled/affiliated      
Schedule of Investments [Line Items]      
Number of investments in portfolio companies | company 11   11
Net realized gain (loss) on investments: $ 8.9 $ (10.0) $ (60.7)