| Document and Entity Information Document | Jan. 08, 2025 |
| Cover [Abstract] | |
| Entity Registrant Name | BLUE OWL CAPITAL CORPORATION III |
| Amendment Flag | false |
| Entity Central Index Key | 0001807427 |
| Document Type | 8-K |
| Document Period End Date | Jan. 08, 2025 |
| Entity Incorporation, State or Country Code | MD |
| Entity File Number | 814-01345 |
| Entity Tax Identification Number | 84-4493477 |
| Entity Address, Address Line One | 399 Park Avenue |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10022 |
| City Area Code | 212 |
| Local Phone Number | 419-3000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock par value $0.01 per share |
| Trading Symbol | OBDE |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
