Acquisition, Dispositions, Goodwill and Other Intangible Assets (Goodwill) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Goodwill [Line Items]
Goodwill - Beginning Balance	$ 27,301
Goodwill Resulting from Business Combinations	109
Goodwill - Foreign Currency Translation and Other	(2)
Goodwill - Ending Balance	27,408
Otis [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	1,566
Goodwill Resulting from Business Combinations	0
Goodwill - Foreign Currency Translation and Other	21
Goodwill - Ending Balance	1,587
UTC Climate, Controls & Security [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	9,458
Goodwill Resulting from Business Combinations	89
Goodwill - Foreign Currency Translation and Other	5
Goodwill - Ending Balance	9,552
Pratt & Whitney [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	1,515
Goodwill Resulting from Business Combinations	0
Goodwill - Foreign Currency Translation and Other	0
Goodwill - Ending Balance	1,515
UTC Aerospace Systems [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	14,759
Goodwill Resulting from Business Combinations	20
Goodwill - Foreign Currency Translation and Other	(28)
Goodwill - Ending Balance	14,751
Total Segments [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	27,298
Goodwill Resulting from Business Combinations	109
Goodwill - Foreign Currency Translation and Other	(2)
Goodwill - Ending Balance	27,405
Eliminations and other [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	3
Goodwill Resulting from Business Combinations	0
Goodwill - Foreign Currency Translation and Other	0
Goodwill - Ending Balance	$ 3