Document and Entity Information	6 Months Ended
	Jun. 30, 2018 USD ($) shares
Document and Entity Information [Abstract]
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Amendment Flag	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Registrant Name	UNITED TECHNOLOGIES CORP /DE/
Entity Central Index Key	0000101829
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float | $	$ 99,985,852,722
Entity Common Stock, Shares Outstanding | shares	800,093,285