Document and Entity Information - USD ($)	9 Months Ended
	Sep. 30, 2017	Jun. 30, 2017
Document and Entity Information [Abstract]
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
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		$ 97,490,067,627
Entity Common Stock, Shares Outstanding	798,569,921