v3.26.1
Cover - USD ($)
 12 Months Ended
Dec. 31, 2025
Apr. 29, 2026
Cover [Abstract]    
Document Type 10-K/A  
Amendment Flag true  
Amendment Description EXPLANATORY NOTE TCW Direct Lending VIII LLC (the “Company”) is filing this Amendment No. 1 on Form 10-K/A (the “Amendment”) to the Company’s annual report on Form 10-K for the year ended December 31, 2025 (the “Form 10-K”), filed with the Securities and Exchange Commission on March 26, 2026 (the “Original Filing”). The Company is filing this Amendment to include the information required by Items 10 through 14 of Part III of Form 10-K that was previously omitted from the Original Filing. Except as set forth in this Amendment, no other changes have been made to the Form 10-K.  
Document Annual Report true  
Document Period End Date Dec. 31, 2025  
Document Fiscal Period Focus FY  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2025  
Document Transition Report false  
Entity File Number 814-01420  
Entity Registrant Name TCW DIRECT LENDING VIII LLC  
Entity Central Index Key 0001825265  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 86-3307898  
Entity Address, Address Line One 200 Clarendon Street  
Entity Address, City or Town Boston  
Entity Address, State or Province MA  
Entity Address, Postal Zip Code 02116  
City Area Code 617  
Local Phone Number 936-2275  
Title of 12(g) Security Common Limited Liability Company Units  
Entity Well-known Seasoned Issuer No  
Entity Voluntary Filers No  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
ICFR Auditor Attestation Flag false  
Document Financial Statement Error Correction [Flag] false  
Entity Shell Company false  
Entity Public Float $ 0  
Entity Common Stock, Shares Outstanding   6,310,260
Documents Incorporated by Reference [Text Block]
Documents Incorporated by Reference
None.
 
Auditor Firm ID 34  
Auditor Name Deloitte & Touche LLP  
Auditor Location Los Angeles, CA, U.S.A.