Acquisition, Dispositions, Goodwill and Other Intangible Assets (Goodwill) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015
Goodwill [Line Items]
Goodwill - Beginning Balance	$ 27,796us-gaap_Goodwill
Goodwill Resulting from Business Combinations	343us-gaap_GoodwillAcquiredDuringPeriod
Goodwill - Foreign Currency Translation and Other	(582)utx_GoodwillTranslationAndOther
Goodwill - Ending Balance	27,557us-gaap_Goodwill
Otis [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	1,664
Goodwill Resulting from Business Combinations	7
Goodwill - Foreign Currency Translation and Other	(81)
Goodwill - Ending Balance	1,590
UTC Climate, Controls & Security [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	9,408
Goodwill Resulting from Business Combinations	336
Goodwill - Foreign Currency Translation and Other	(312)
Goodwill - Ending Balance	9,432
Pratt & Whitney [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	1,481
Goodwill Resulting from Business Combinations	0
Goodwill - Foreign Currency Translation and Other	(1)
Goodwill - Ending Balance	1,480
UTC Aerospace Systems [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	14,892
Goodwill Resulting from Business Combinations	0
Goodwill - Foreign Currency Translation and Other	(185)
Goodwill - Ending Balance	14,707
Sikorsky [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	347
Goodwill Resulting from Business Combinations	0
Goodwill - Foreign Currency Translation and Other	(3)
Goodwill - Ending Balance	344
Total Segments [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	27,792
Goodwill Resulting from Business Combinations	343
Goodwill - Foreign Currency Translation and Other	(582)
Goodwill - Ending Balance	27,553
Eliminations and other [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	4
Goodwill Resulting from Business Combinations	0
Goodwill - Foreign Currency Translation and Other	0
Goodwill - Ending Balance	$ 4

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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- Definition

Reflects net changes to the recorded value of goodwill for foreign currency translation adjustments and other adjustments needed to revise the carrying amount of goodwill to fair value.

+ References

No definition available.

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