Restructuring and Other Costs (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				$ 201
Net pre-tax restructuring costs (reversals)	$ 32
Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				110
Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				65
Other Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				26
Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				143
Restructuring Reserve	99	$ 87		99
Net pre-tax restructuring costs (reversals)	30	85	$ 28	143
Utilization and foreign exchange	18			44
Expected Costs	242			242
Remaining Costs	99			99
Current Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				71
Current Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				46
Current Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	37	27		37
Net pre-tax restructuring costs (reversals)	22			71
Utilization and foreign exchange	12			34
Current Year Actions [Member] | Facility Exit, Lease Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	62	60		62
Net pre-tax restructuring costs (reversals)	8			72
Utilization and foreign exchange	6			10
Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				44
Restructuring Reserve	91	138		91	$ 206
Net pre-tax restructuring costs (reversals)	(9)	24	29	44	326
Utilization and foreign exchange	38			159
Expected Costs	473			473
Remaining Costs	103			103
Prior Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				35
Prior Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				9
Prior Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	63	113		63	183
Net pre-tax restructuring costs (reversals)	(14)			23
Utilization and foreign exchange	36			143
Prior Year Actions [Member] | Facility Exit, Lease Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	28	25		28	23
Net pre-tax restructuring costs (reversals)	5			21
Utilization and foreign exchange	2			16
Two Years Prior Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	42			42
Otis [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				41
Otis [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	9	13	10
Expected Costs	38			38
Remaining Costs	6			6
Otis [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	2	5	5		35
Expected Costs	51			51
Remaining Costs	4			4
UTC Climate, Controls & Security [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				71
UTC Climate, Controls & Security [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	13	8	13
Expected Costs	53			53
Remaining Costs	19			19
UTC Climate, Controls & Security [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	5	14	14		83
Expected Costs	195			195
Remaining Costs	79			79
Pratt & Whitney [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				50
Pratt & Whitney [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	0	61	0
Expected Costs	61			61
Remaining Costs	0			0
Pratt & Whitney [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	(24)	0	1		82
Expected Costs	59			59
Remaining Costs	0			0
UTC Aerospace Systems [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				32
UTC Aerospace Systems [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	8	3	5
Expected Costs	90			90
Remaining Costs	74			74
UTC Aerospace Systems [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	3	4	8		105
Expected Costs	140			140
Remaining Costs	20			20
Eliminations and other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				7
Eliminations and other [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	5	$ 1	$ 1		$ 21
Expected Costs	28			28
Remaining Costs	$ 0			$ 0