Amount of fees and commissions from banking, advisory, brokerage, and securities underwriting activities. Activities include, but are not limited to, underwriting securities, private placements of securities, investment advisory and management services, merger and acquisition services, sale and servicing of mutual funds, and other related consulting fees.

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Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Structuring Fees
Related Party Transaction [Line Items]
Structuring fee revenue	$ 15	$ 21
FS/KKR Advisor, LLC \| Investment Advisory Agreement - Incentive Rate, Realized Capital Gains
Related Party Transaction [Line Items]
Incentive fee (in percent)	20.00%
FS/KKR Advisor, LLC \| Investment Advisory Agreement - Incentive Rate, Quarterly In Arrears Catch-up Threshold
Related Party Transaction [Line Items]
Incentive fee (in percent)	17.50%
FS/KKR Advisor, LLC \| Investment Advisory Agreement - Incentive Rate, Quarterly Catch-up Threshold
Related Party Transaction [Line Items]
Incentive fee (in percent)	1.75%
FS/KKR Advisor, LLC \| Investment Advisory Agreement - Incentive Rate, Annualized Hurdle Rate
Related Party Transaction [Line Items]
Incentive fee (in percent)	7.00%
FS/KKR Advisor, LLC \| Investment Advisory Agreement - Incentive Rate, Pre-Incentive Fee Net Investment Income Below Catch-Up Threshold
Related Party Transaction [Line Items]
Incentive fee (in percent)	2.12%
FS/KKR Advisor, LLC \| Investment Advisory Agreement - Incentive Rate, Annualized Catch-Up Threshold
Related Party Transaction [Line Items]
Incentive fee (in percent)	8.48%