Cover Page - shares	2 Months Ended
	Jun. 30, 2024	Aug. 26, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Document Period End Date	Jun. 30, 2024
Document Quarterly Report	true
Document Transition Report	false
Current Fiscal Year End Date	--12-31
Entity Registrant Name	Grayscale Bitcoin Mini Trust (BTC)
Entity Central Index Key	0002015034
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	No
Entity Interactive Data Current	Yes
Entity File Number	001-42194
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	99-6383052
Entity Address, Address Line One	c/o Grayscale Investments, LLC
Entity Address, Address Line Two	290 Harbor Drive, 4th Floor
City Area Code	212
Local Phone Number	668-1427
Entity Address, City or Town	Stamford
Entity Address, Postal Zip Code	06902
Entity Address, State or Province	CT
Entity Common Stock, Shares Outstanding		368,630,100
Title of 12(b) Security	Grayscale Bitcoin Mini Trust (BTC) Shares
Trading Symbol	BTC
Security Exchange Name	NYSEArca