| Cover | Mar. 01, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Mar. 01, 2024 |
| Entity Registrant Name | CARLYLE SECURED LENDING III |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 814-01410 |
| Entity Tax Identification Number | 86-6498423 |
| Entity Address, Address Line One | One Vanderbilt Avenue, |
| Entity Address, Address Line Two | Suite 3400 |
| Entity Address, City or Town | New York, |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10017 |
| City Area Code | 212 |
| Local Phone Number | 813-4900 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity Central Index Key | 0001851277 |
| Amendment Flag | false |
