| Document and Entity Information | Jan. 12, 2024 |
| Cover [Abstract] | |
| Entity Registrant Name | Blue Owl Capital Corp II |
| Entity Address, State or Province | NY |
| Amendment Flag | false |
| Entity Central Index Key | 0001655887 |
| Document Type | 8-K |
| Document Period End Date | Jan. 12, 2024 |
| Entity Incorporation State Country Code | MD |
| Entity File Number | 814-01219 |
| Entity Tax Identification Number | 47-5416332 |
| Entity Address, Address Line One | 399 Park Avenue |
| Entity Address, City or Town | New York |
| Entity Address, Postal Zip Code | 10022 |
| City Area Code | (212) |
| Local Phone Number | 419-3000 |
| Written Communications | false |
| Entity Emerging Growth Company | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
