Restructuring and Other Costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				$ 343
Restructuring costs recorded with continuing operations				345
Restructuring costs recorded within discontinued operations				(2)
Restructuring Reserve, Two Years Prior Actions	5			5
Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	160
Restructuring Charges	96			298
Restructuring Reserve Settled	(111)
Restructuring Reserve Ending Balance	145	160		145
Restructuring and Related Cost, Incurred Cost	(96)	(182)	(20)
Anticipated Net Workforce Reduction Of Hourly And Salary Employees				approximately 3,600 hourly and salaried employees
Anticipated Net Square Feet Of Facilities To Be Exited				approximately 600 thousand net square feet
Completed Net Workforce Reduction Of Hourly And Salary Employees				approximately 2,400 employees
Completed Net Square Feet Of Facilities Exited				approximately 5,000 net square feet
Restructuring and Related Cost, Expected Cost				341
Restructuring And Related Cost Expected Remaining	43			43
Current Year Actions [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	153
Restructuring Charges	89
Restructuring Reserve Settled	(108)
Restructuring Reserve Ending Balance	134	153		134
Restructuring and Related Cost, Incurred Cost	(89)	(163)	(19)
Restructuring and Related Cost, Expected Cost				287
Restructuring And Related Cost Expected Remaining	16			16
Current Year Actions [Member] | Asset Write Downs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	0
Restructuring Charges	1
Restructuring Reserve Settled	(1)
Restructuring Reserve Ending Balance	0	0		0
Restructuring and Related Cost, Incurred Cost	(1)	(12)	0
Restructuring and Related Cost, Expected Cost				13
Restructuring And Related Cost Expected Remaining	0			0
Current Year Actions [Member] | Facility Exit [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	7
Restructuring Charges	6
Restructuring Reserve Settled	(2)
Restructuring Reserve Ending Balance	11	7		11
Restructuring and Related Cost, Incurred Cost	(6)	(7)	(1)
Restructuring and Related Cost, Expected Cost				41
Restructuring And Related Cost Expected Remaining	27			27
Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	189
Restructuring Charges	6			44
Restructuring Reserve Settled	(45)
Restructuring Reserve Ending Balance	150	189		150
Restructuring and Related Cost, Incurred Cost	(6)	(9)	(29)		(576)
Anticipated Net Workforce Reduction Of Hourly And Salary Employees				7,300 employees
Anticipated Net Square Feet Of Facilities To Be Exited				3.6 million net square feet
Completed Net Workforce Reduction Of Hourly And Salary Employees				approximately 6,100 employees
Completed Net Square Feet Of Facilities Exited				1.6 million net square feet
Restructuring and Related Cost, Expected Cost				660
Restructuring And Related Cost Expected Remaining	40			40
Prior Year Actions [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	142
Restructuring Charges	(3)
Restructuring Reserve Settled	(32)
Restructuring Reserve Ending Balance	107	142		107
Restructuring and Related Cost, Incurred Cost	3	1	(18)		(452)
Restructuring and Related Cost, Expected Cost				477
Restructuring And Related Cost Expected Remaining	11			11
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	0		0
Restructuring and Related Cost, Incurred Cost	0	0	(1)		(14)
Restructuring and Related Cost, Expected Cost				15
Restructuring And Related Cost Expected Remaining	0			0
Prior Year Actions [Member] | Facility Exit [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	47
Restructuring Charges	9
Restructuring Reserve Settled	(13)
Restructuring Reserve Ending Balance	43	47		43
Restructuring and Related Cost, Incurred Cost	(9)	(10)	(10)		(110)
Restructuring and Related Cost, Expected Cost				168
Restructuring And Related Cost Expected Remaining	29			29
Otis [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				68
Otis [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(12)	(35)	(6)
Restructuring and Related Cost, Expected Cost				61
Restructuring And Related Cost Expected Remaining	8			8
Otis [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(1)	(2)	(1)		(146)
Restructuring and Related Cost, Expected Cost				157
Restructuring And Related Cost Expected Remaining	7			7
UTC Climate Controls and Security [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				66
UTC Climate Controls and Security [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(34)	(18)	(8)
Restructuring and Related Cost, Expected Cost				81
Restructuring And Related Cost Expected Remaining	21			21
UTC Climate Controls and Security [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	1	(1)	(14)		(123)
Restructuring and Related Cost, Expected Cost				149
Restructuring And Related Cost Expected Remaining	12			12
Pratt and Whitney [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				122
Pratt and Whitney [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(22)	(93)	(6)
Restructuring and Related Cost, Expected Cost				127
Restructuring And Related Cost Expected Remaining	6			6
Pratt and Whitney [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	0	0	(1)		(94)
Restructuring and Related Cost, Expected Cost				98
Restructuring And Related Cost Expected Remaining	3			3
UTC Aerospace Systems [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				65
UTC Aerospace Systems [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(19)	(28)	0
Restructuring and Related Cost, Expected Cost				55
Restructuring And Related Cost Expected Remaining	8			8
UTC Aerospace Systems [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(5)	(5)	(8)		(121)
Restructuring and Related Cost, Expected Cost				154
Restructuring And Related Cost Expected Remaining	15			15
Sikorsky [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				25
Sikorsky [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(10)	(8)	0
Restructuring and Related Cost, Expected Cost				18
Restructuring And Related Cost Expected Remaining	0			0
Sikorsky [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	(1)	(1)	(5)		(47)
Restructuring and Related Cost, Expected Cost				57
Restructuring And Related Cost Expected Remaining	3			3
Eliminations and other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				(1)
Eliminations and other [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	1	0	0
Restructuring and Related Cost, Expected Cost				(1)
Restructuring And Related Cost Expected Remaining	0			0
Eliminations and other [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	0	0	0		(19)
Restructuring and Related Cost, Expected Cost				19
Restructuring And Related Cost Expected Remaining	0			0
Discontinued Operations [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	0	0	0		(26)
Restructuring and Related Cost, Expected Cost				26
Restructuring And Related Cost Expected Remaining	0			0
Cost Of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				145
Cost Of Sales [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				100
Cost Of Sales [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				40
Selling General and Administrative [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				199
Selling General and Administrative [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				198
Selling General and Administrative [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				3
Discontinued Operations [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				(2)
Other Income [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				1
Other Income [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				$ 1