v3.26.1
Financing Arrangements - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Jun. 15, 2019
Jun. 14, 2019
Debt Instrument [Line Items]          
Asset coverage per ratio (as percent) 172.00% 182.00%      
Long term outstanding $ 7,290 $ 8,009 $ 7,620    
Average outstanding amount $ 7,556 $ 7,829      
Weighted average interest rate (as percent) 5.26% 5.50%      
Effective interest rate percentage (as percent) 5.27% 5.48%      
Investment Advisory Agreement | FS/KKR Advisor, LLC          
Debt Instrument [Line Items]          
Asset coverage per ratio (as percent)       150.00% 200.00%