| Document and Entity Information | Sep. 06, 2023 |
| Cover [Abstract] | |
| Entity Registrant Name | TCW STRATEGIC INCOME FUND INC |
| Amendment Flag | false |
| Entity Central Index Key | 0000809559 |
| Document Type | 8-K |
| Document Period End Date | Sep. 06, 2023 |
| Entity Incorporation State Country Code | MD |
| Entity File Number | 811-04980 |
| Entity Tax Identification Number | 93-0939398 |
| Entity Address, Address Line One | 865 S. Figueroa |
| Entity Address, Address Line Two | Suite 1800 |
| Entity Address, City or Town | Los Angeles |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 90017 |
| City Area Code | (213) |
| Local Phone Number | 244-0000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
