Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 11, 2021
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Filer Category	Non-accelerated Filer
Entity Registrant Name	ELECTRO SENSORS INC
Entity Central Index Key	0000351789
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Small Business	true
Entity Common Stock, Shares Outstanding		3,395,521
Trading Symbol	ELSE
Entity Emerging Growth Company	false
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	000-09587
Entity Incorporation, State or Country Code	MN
Entity Tax Identification Number	41-0943459
Entity Address, Address Line One	6111 Blue Circle Drive
Entity Address, City or Town	Minnetonka
Entity Address, State or Province	MN
Entity Address, Postal Zip Code	55343-9108
City Area Code	952
Local Phone Number	930-0100
Title of 12(b) Security	Common stock
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Entity Shell Company	false