Restructuring and Other Costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	$ 93
Restructuring Reserve, Two Years Prior Actions	71
Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	64
Utilization and foreign exchange	3
Restructuring Reserve Ending Balance	61
Restructuring and Related Cost, Incurred Cost	64
Restructuring and Related Cost, Expected Cost	71
Restructuring And Related Cost Expected Remaining	7
Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	171
Net pre-tax restructuring costs	23
Utilization and foreign exchange	56
Restructuring Reserve Ending Balance	138	171
Restructuring and Related Cost, Incurred Cost	23	345
Restructuring and Related Cost, Expected Cost	455
Restructuring And Related Cost Expected Remaining	87
Prior Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	162
Net pre-tax restructuring costs	14
Utilization and foreign exchange	46
Restructuring Reserve Ending Balance	130
Prior Year Actions [Member] | Facility Exit, Lease Termination and Other Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	9
Net pre-tax restructuring costs	9
Utilization and foreign exchange	10
Restructuring Reserve Ending Balance	8
Otis [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	6
Otis [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	0
Restructuring and Related Cost, Expected Cost	1
Restructuring And Related Cost Expected Remaining	1
Otis [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	6	98
Restructuring and Related Cost, Expected Cost	133
Restructuring And Related Cost Expected Remaining	29
UTC Climate, Controls & Security [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	24
UTC Climate, Controls & Security [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	16
Restructuring and Related Cost, Expected Cost	20
Restructuring And Related Cost Expected Remaining	4
UTC Climate, Controls & Security [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	7	86
Restructuring and Related Cost, Expected Cost	127
Restructuring And Related Cost Expected Remaining	34
Pratt & Whitney [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	13
Pratt & Whitney [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	1
Restructuring and Related Cost, Expected Cost	1
Restructuring And Related Cost Expected Remaining	0
Pratt & Whitney [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	10	64
Restructuring and Related Cost, Expected Cost	86
Restructuring And Related Cost Expected Remaining	12
UTC Aerospace Systems [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	50
UTC Aerospace Systems [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	47
Restructuring and Related Cost, Expected Cost	49
Restructuring And Related Cost Expected Remaining	2
UTC Aerospace Systems [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	0	72
Restructuring and Related Cost, Expected Cost	84
Restructuring And Related Cost Expected Remaining	12
Sikorsky [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	0	20
Restructuring and Related Cost, Expected Cost	20
Restructuring And Related Cost Expected Remaining	0
Eliminations and other [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	0	5
Restructuring and Related Cost, Expected Cost	5
Restructuring And Related Cost Expected Remaining	0
Cost Of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	22
Cost Of Sales [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	5
Cost Of Sales [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	14
Selling General and Administrative [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	71
Selling General and Administrative [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	59
Selling General and Administrative [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	$ 9