Acquisition, Dispositions, Goodwill and Other Intangible Assets (Goodwill) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016 USD ($)
Goodwill [Line Items]
Goodwill - Beginning Balance	$ 27,301
Goodwill Resulting from Business Combinations	494
Goodwill - Foreign Currency Translation and Other	(373)
Goodwill - Ending Balance	27,422
Otis [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	1,566
Goodwill Resulting from Business Combinations	19
Goodwill - Foreign Currency Translation and Other	49
Goodwill - Ending Balance	1,634
UTC Climate, Controls & Security [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	9,458
Goodwill Resulting from Business Combinations	450
Goodwill - Foreign Currency Translation and Other	(208)
Goodwill - Ending Balance	9,700
Pratt & Whitney [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	1,515
Goodwill Resulting from Business Combinations	0
Goodwill - Foreign Currency Translation and Other	(4)
Goodwill - Ending Balance	1,511
UTC Aerospace Systems [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	14,759
Goodwill Resulting from Business Combinations	25
Goodwill - Foreign Currency Translation and Other	(210)
Goodwill - Ending Balance	14,574
Total Segments [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	27,298
Goodwill Resulting from Business Combinations	494
Goodwill - Foreign Currency Translation and Other	(373)
Goodwill - Ending Balance	27,419
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