v3.26.3
Related Party Transactions - Schedule of Fees and Expenses Accrued Under the Investment Advisory Agreement (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Related Party Transaction [Line Items]          
Base Management Fee $ 42.0 $ 51.0 $ 134.0 $ 156.0  
Subordinated Income Incentive Fee 23.0 33.0 71.0 108.0  
Administrative Services Expenses 1.0 1.0 3.0 3.0  
Management fees payable 42.0   42.0   $ 50.0
Subordinated income incentive fees payable 12.0   12.0   $ 28.0
FS/KKR Advisor, LLC          
Related Party Transaction [Line Items]          
Base Management Fee 42.0 51.0 134.0 156.0  
Subordinated Income Incentive Fee 11.0 33.0 48.0 108.0  
Administrative Services Expenses 3.0 $ 3.0 8.0 8.0  
Base management fees     142.0 158.0  
Management fees payable 42.0   $ 42.0    
Incentive fee waived     50.00%    
Investment company, incentive fee waived     $ 23.0    
Incentive fee paid     64.0 110.0  
Subordinated income incentive fees payable $ 12.0   12.0    
Allocation of costs of administrative personnel for services rendered     7.0 6.0  
Broken deal cost     0.2    
Payment for administrative services expenses     $ 5.0 $ 4.0