v3.25.2
Document and Entity Information
Jul. 31, 2025
Cover [Abstract]  
Amendment Flag false
Entity Central Index Key 0002049595
Document Type 8-K
Document Period End Date Jul. 31, 2025
Entity Registrant Name BlackRock Monticello Debt Real Estate Investment Trust
Entity Incorporation State Country Code MD
Entity File Number 000-56720
Entity Tax Identification Number 33-6595754
Entity Address, Address Line One 50 Hudson Yards
Entity Address, City or Town New York
Entity Address, State or Province NY
Entity Address, Postal Zip Code 10001
City Area Code (212)
Local Phone Number 810-5300
Written Communications false
Soliciting Material false
Pre Commencement Tender Offer false
Pre Commencement Issuer Tender Offer false
Entity Emerging Growth Company true
Entity Ex Transition Period false