Document and Entity Information	9 Months Ended
	Sep. 30, 2019 shares
Document and Entity Information
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Entity Registrant Name	Tri-State Generation & Transmission Association, Inc.
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	0
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001637880
Amendment Flag	false