Acquisition, Dispositions, Goodwill and Other Intangible Assets (Goodwill) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Goodwill [Line Items]
Goodwill - Beginning Balance	$ 27,801
Goodwill resulting from business combinations	426
Goodwill translation and other	(392)
Goodwill - Ending Balance	27,835
Otis [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	1,583
Goodwill resulting from business combinations	126
Goodwill translation and other	(62)
Goodwill - Ending Balance	1,647
UTC Climate Controls and Security [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	9,868
Goodwill resulting from business combinations	2
Goodwill translation and other	(253)
Goodwill - Ending Balance	9,617
UTC Aerospace Systems [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	14,754
Goodwill resulting from business combinations	298
Goodwill translation and other	(107)
Goodwill - Ending Balance	14,945
Pratt and Whitney [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	1,238
Goodwill resulting from business combinations	0
Goodwill translation and other	35
Goodwill - Ending Balance	1,273
Sikorsky [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	353
Goodwill resulting from business combinations	0
Goodwill translation and other	(4)
Goodwill - Ending Balance	349
Total Segments [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	27,796
Goodwill resulting from business combinations	426
Goodwill translation and other	(391)
Goodwill - Ending Balance	27,831
Eliminations and other [Member]
Goodwill [Line Items]
Goodwill - Beginning Balance	5
Goodwill resulting from business combinations	0
Goodwill translation and other	(1)
Goodwill - Ending Balance	$ 4