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)