Restructuring and Other Costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 125
Restructuring Reserve, Two Years Prior Actions	97
Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	90
Restructuring Reserve Settled	(10)
Restructuring Reserve Ending Balance	80
Restructuring and Related Cost, Incurred Cost	(90)
Restructuring and Related Cost, Expected Cost	148
Restructuring And Related Cost Expected Remaining	58
Current Year Actions [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	85
Restructuring Reserve Settled	(5)
Restructuring Reserve Ending Balance	80
Current Year Actions [Member] | Asset Write Downs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	3
Restructuring Reserve Settled	(3)
Restructuring Reserve Ending Balance	0
Current Year Actions [Member] | Facility Exit [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	2
Restructuring Reserve Settled	(2)
Restructuring Reserve Ending Balance	0
Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	215
Restructuring Charges	32
Restructuring Reserve Settled	(53)
Restructuring Reserve Ending Balance	194	215
Restructuring and Related Cost, Incurred Cost	(32)	(421)
Restructuring and Related Cost, Expected Cost	487
Restructuring And Related Cost Expected Remaining	34
Prior Year Actions [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	196
Restructuring Charges	28
Restructuring Reserve Settled	(52)
Restructuring Reserve Ending Balance	172
Prior Year Actions [Member] | Asset Write Downs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	0
Restructuring Charges	0
Restructuring Reserve Settled	0
Restructuring Reserve Ending Balance	0
Prior Year Actions [Member] | Facility Exit [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	19
Restructuring Charges	4
Restructuring Reserve Settled	(1)
Restructuring Reserve Ending Balance	22
Otis [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	17
Otis [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(18)
Restructuring and Related Cost, Expected Cost	31
Restructuring And Related Cost Expected Remaining	13
Otis [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(1)	(69)
Restructuring and Related Cost, Expected Cost	74
Restructuring And Related Cost Expected Remaining	4
UTC Climate Controls and Security [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	43
UTC Climate Controls and 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	33
Restructuring And Related Cost Expected Remaining	17
UTC Climate Controls and Security [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(24)	(89)
Restructuring and Related Cost, Expected Cost	124
Restructuring And Related Cost Expected Remaining	11
Pratt and Whitney [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	42
Pratt and Whitney [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(37)
Restructuring and Related Cost, Expected Cost	65
Restructuring And Related Cost Expected Remaining	28
Pratt and Whitney [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(6)	(154)
Restructuring and Related Cost, Expected Cost	162
Restructuring And Related Cost Expected Remaining	2
UTC Aerospace Systems [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	6
UTC Aerospace Systems [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(3)
Restructuring and Related Cost, Expected Cost	3
Restructuring And Related Cost Expected Remaining	0
UTC Aerospace Systems [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(1)	(71)
Restructuring and Related Cost, Expected Cost	89
Restructuring And Related Cost Expected Remaining	17
Sikorsky [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	17
Sikorsky [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(16)
Restructuring and Related Cost, Expected Cost	16
Restructuring And Related Cost Expected Remaining	0
Sikorsky [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	0	(38)
Restructuring and Related Cost, Expected Cost	38
Restructuring And Related Cost Expected Remaining	0
Cost Of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	86
Cost Of Sales [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	56
Cost Of Sales [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	28
Selling General and Administrative [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	39
Selling General and Administrative [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	34
Selling General and Administrative [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 4