Segment Financial Data (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Total net sales	$ 14,354	$ 13,788	$ 42,585	$ 41,798
Operating profit	$ 2,251	$ 2,302	$ 6,533	$ 6,899
Operating profit margin	15.70%	16.70%	15.30%	16.50%
Otis [Member]
Segment Reporting Information [Line Items]
Total net sales	$ 3,018	$ 3,043	$ 8,830	$ 8,886
Operating profit	$ 584	$ 642	$ 1,631	$ 1,796
Operating profit margin	19.40%	21.10%	18.50%	20.20%
UTC Climate, Controls & Security [Member]
Segment Reporting Information [Line Items]
Total net sales	$ 4,415	$ 4,279	$ 12,602	$ 12,585
Operating profit	$ 801	$ 771	$ 2,279	$ 2,323
Operating profit margin	18.10%	18.00%	18.10%	18.50%
Pratt & Whitney [Member]
Segment Reporting Information [Line Items]
Total net sales	$ 3,501	$ 3,234	$ 10,902	$ 10,243
Operating profit	$ 340	$ 419	$ 1,136	$ 1,325
Operating profit margin	9.70%	13.00%	10.40%	12.90%
UTC Aerospace Systems [Member]
Segment Reporting Information [Line Items]
Total net sales	$ 3,646	$ 3,457	$ 10,867	$ 10,637
Operating profit	$ 600	$ 572	$ 1,720	$ 1,721
Operating profit margin	16.50%	16.50%	15.80%	16.20%
Total Segments [Member]
Segment Reporting Information [Line Items]
Total net sales	$ 14,580	$ 14,013	$ 43,201	$ 42,351
Operating profit	$ 2,325	$ 2,404	$ 6,766	$ 7,165
Operating profit margin	15.90%	17.20%	15.70%	16.90%
Eliminations and other [Member]
Segment Reporting Information [Line Items]
Total net sales	$ (226)	$ (225)	$ (616)	$ (553)
Operating profit	18	(1)	47	65
General corporate expenses [Member]
Segment Reporting Information [Line Items]
Total net sales	0	0	0	0
Operating profit	$ (92)	$ (101)	$ (280)	$ (331)