COMMITMENTS AND CONTINGENCIES - Loan Commitments (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Other Commitments [Line Items]
Total net unfunded revolving loan commitments	$ 76.0	$ 32.0
Revolving and delayed draw loan commitments
Other Commitments [Line Items]
Total revolving loan commitments	5,392.1	5,722.7
Less: funded commitments	(676.3)	(491.5)
Less: unavailable loan commitments due to borrowing base or other covenant restrictions	(53.1)	(41.1)
Total net unfunded revolving loan commitments	4,715.8	5,231.2
Total net unfunded revolving and delayed draw loan commitments	4,663.0	5,190.0
Revolving loan commitments
Other Commitments [Line Items]
Total revolving loan commitments	2,996.0	2,734.0
Less: funded commitments	(676.0)	(492.0)
Less: unavailable loan commitments due to borrowing base or other covenant restrictions	(18.0)	(11.0)
Total net unfunded revolving loan commitments	2,302.0	2,231.0
Delayed draw loan commitments
Other Commitments [Line Items]
Total revolving loan commitments	2,396.0	2,989.0
Less: unavailable loan commitments due to borrowing base or other covenant restrictions	(35.0)	(30.0)
Total net unfunded revolving loan commitments	$ 2,361.0	$ 2,959.0

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Amount of financial support committed by investment company to investee that is contractually required but not provided.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480990/946-20-50-16

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Amount of financial support committed by investment company to investee that is contractually required.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480990/946-20-50-15

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480990/946-20-50-15

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