Acquisition, Dispositions, Goodwill and Other Intangible Assets (Goodwill) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($)
Goodwill [Line Items]
Goodwill - Beginning Balance	$ 27,448
Goodwill Resulting from Business Combinations	429
Goodwill - Foreign Currency Translation and Other	(523)
Goodwill - Ending Balance	27,354
Otis [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	1,664
Goodwill Resulting from Business Combinations	6
Goodwill - Foreign Currency Translation and Other	(121)
Goodwill - Ending Balance	1,549
UTC Climate, Controls & Security [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	9,408
Goodwill Resulting from Business Combinations	386
Goodwill - Foreign Currency Translation and Other	(267)
Goodwill - Ending Balance	9,527
Pratt & Whitney [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	1,481
Goodwill Resulting from Business Combinations	36
Goodwill - Foreign Currency Translation and Other	0
Goodwill - Ending Balance	1,517
UTC Aerospace Systems [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	14,892
Goodwill Resulting from Business Combinations	0
Goodwill - Foreign Currency Translation and Other	(135)
Goodwill - Ending Balance	14,757
Total Segments [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	27,445
Goodwill Resulting from Business Combinations	428
Goodwill - Foreign Currency Translation and Other	(523)
Goodwill - Ending Balance	27,350
Eliminations and other [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	3
Goodwill Resulting from Business Combinations	1
Goodwill - Foreign Currency Translation and Other	0
Goodwill - Ending Balance	$ 4