v3.26.1

Cover - USD ($)	12 Months Ended
Cover - USD ($)	Dec. 31, 2025	Apr. 29, 2026
Cover [Abstract]
Document Type	10-K/A
Amendment Flag	true
Document Period End Date	Dec. 31, 2025
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	FY
Entity Registrant Name	TCW Steel City Senior Lending BDC
Entity Central Index Key	0002043133
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		12,093,673
Entity Public Float	$ 0
Entity File Number	000-56771
Entity Tax Identification Number	33-1515587
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
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Document Annual Report	true
Document Transition Report	false
Document Financial Statement Error Correction [Flag]	false
ICFR Auditor Attestation Flag	false
Documents Incorporated by Reference [Text Block]	None.
Amendment Description	EXPLANATORY NOTE TCW Steel City Senior Lending BDC (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.
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Los Angeles, California, United States of America
Entity Ex Transition Period	false

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TCW Steel City Senior Lending BDC 10-K/A