Restructuring and Other Costs (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			$ 240
Restructuring Reserve Ending Balance		13
Restructuring costs recorded with continuing operations			242
Restructuring costs recorded within discontinued operations			(2)
Restructuring Reserve, Two Years Prior Actions	17		17
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Ending Balance		13
Asset Write Downs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Ending Balance		0
Facility Exit [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Ending Balance		0
Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	182		202
Restructuring Reserve Settled	(35)
Restructuring Reserve Ending Balance	160		160
Restructuring and Related Cost, Incurred Cost	182	20
Anticipated Net Workforce Reduction Of Hourly And Salary Employees			approximately 2,400 hourly and salaried employees
Anticipated Net Square Feet Of Facilities To Be Exited			approximately 400 thousand net square feet
Completed Net Workforce Reduction Of Hourly And Salary Employees			approximately 700 employees
Restructuring and Related Cost, Expected Cost			260
Restructuring And Related Cost Expected Remaining	58		58
Current Year Actions [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	163
Restructuring Reserve Settled	(23)
Restructuring Reserve Ending Balance	153		153
Restructuring and Related Cost, Incurred Cost	163	19
Restructuring and Related Cost, Expected Cost			215
Restructuring And Related Cost Expected Remaining	33		33
Current Year Actions [Member] | Asset Write Downs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	12
Restructuring Reserve Settled	(12)
Restructuring Reserve Ending Balance	0		0
Restructuring and Related Cost, Incurred Cost	12	0
Restructuring and Related Cost, Expected Cost			12
Restructuring And Related Cost Expected Remaining	0		0
Current Year Actions [Member] | Facility Exit [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	7
Restructuring Reserve Settled	0
Restructuring Reserve Ending Balance	7		7
Restructuring and Related Cost, Incurred Cost	7	1
Restructuring and Related Cost, Expected Cost			33
Restructuring And Related Cost Expected Remaining	25		25
Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	252
Restructuring Charges	9		38
Restructuring Reserve Settled	(72)
Restructuring Reserve Ending Balance	189	252	189
Restructuring and Related Cost, Incurred Cost	9	29		576
Anticipated Net Workforce Reduction Of Hourly And Salary Employees			7,100 employees
Anticipated Net Square Feet Of Facilities To Be Exited			3 million net square feet
Completed Net Workforce Reduction Of Hourly And Salary Employees			approximately 5,900 employees
Completed Net Square Feet Of Facilities Exited			1.4 million net square feet
Restructuring and Related Cost, Expected Cost			657
Restructuring And Related Cost Expected Remaining	43		43
Prior Year Actions [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve Beginning Balance	201
Restructuring Charges	(1)
Restructuring Reserve Settled	(58)
Restructuring Reserve Ending Balance	142	201	142
Restructuring and Related Cost, Incurred Cost	(1)	18		452
Restructuring and Related Cost, Expected Cost			480
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	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	51
Restructuring Charges	10
Restructuring Reserve Settled	(14)
Restructuring Reserve Ending Balance	47	51	47
Restructuring and Related Cost, Incurred Cost	10	10		110
Restructuring and Related Cost, Expected Cost			162
Restructuring And Related Cost Expected Remaining	32		32
Otis [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			49
Otis [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	35	6
Restructuring and Related Cost, Expected Cost			53
Restructuring And Related Cost Expected Remaining	12		12
Otis [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	2	1		146
Restructuring and Related Cost, Expected Cost			154
Restructuring And Related Cost Expected Remaining	5		5
UTC Climate Controls and Security [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			38
UTC Climate Controls and Security [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	18	8
Restructuring and Related Cost, Expected Cost			51
Restructuring And Related Cost Expected Remaining	25		25
UTC Climate Controls and Security [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	1	14		123
Restructuring and Related Cost, Expected Cost			153
Restructuring And Related Cost Expected Remaining	15		15
Pratt and Whitney [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			100
Pratt and Whitney [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	93	6
Restructuring and Related Cost, Expected Cost			111
Restructuring And Related Cost Expected Remaining	12		12
Pratt and Whitney [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	0	1		94
Restructuring and Related Cost, Expected Cost			99
Restructuring And Related Cost Expected Remaining	4		4
UTC Aerospace Systems [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			41
UTC Aerospace Systems [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	28	0
Restructuring and Related Cost, Expected Cost			37
Restructuring And Related Cost Expected Remaining	9		9
UTC Aerospace Systems [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	5	8		121
Restructuring and Related Cost, Expected Cost			152
Restructuring And Related Cost Expected Remaining	18		18
Sikorsky [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			14
Sikorsky [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	8	0
Restructuring and Related Cost, Expected Cost			8
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	5		47
Restructuring and Related Cost, Expected Cost			54
Restructuring And Related Cost Expected Remaining	1		1
Eliminations and other [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	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		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			101
Cost Of Sales [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			68
Cost Of Sales [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			31
Selling General and Administrative [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			140
Selling General and Administrative [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			134
Selling General and Administrative [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			6
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