Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Weighted average interest rate of debt outstanding.

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No definition available.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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Percentage of total assets less all liabilities and indebtedness not represented by senior security, to senior security representing indebtedness.

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The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

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Average amount outstanding of long-term debt.

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Financing Arrangements - Narrative (Details) - USD ($)			3 Months Ended		6 Months Ended		12 Months Ended
Financing Arrangements - Narrative (Details) - USD ($)	Jun. 05, 2025	Jun. 02, 2025	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024	Jun. 15, 2019	Jun. 14, 2019
Debt Instrument [Line Items]
Asset coverage per ratio (as percent)			177.00%	184.00%	177.00%	184.00%
Long term outstanding			$ 8,022,000,000	$ 8,001,000,000	$ 8,022,000,000	$ 8,001,000,000	$ 7,385,000,000
Average outstanding amount					$ 8,212,000,000	$ 8,176,000,000
Weighted average interest rate (as percent)			5.51%	5.42%	5.51%	5.42%
Effective interest rate percentage (as percent)			5.34%	5.34%	5.34%	5.34%
Realized loss on extinguishment of debt			$ 3,000,000	$ 0	$ 3,000,000	$ 0
Revolving Credit Facility \| Callowhill Street Funding LLC \| Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 400,000,000
Basis spread on variable rate (as percent)		1.75%
Commitment fee (as percent)		0.50%
Revolving Credit Facility \| Darby Creek Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Long term outstanding							$ 500,000,000
Basis spread on variable rate (as percent)							2.65%
Realized loss on extinguishment of debt	$ 3,000,000
Investment Advisory Agreement \| FS/KKR Advisor, LLC
Debt Instrument [Line Items]
Asset coverage per ratio (as percent)								150.00%	200.00%