Restructuring and Other Costs (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 52
Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	21
Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	31
Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	24
Restructuring Reserve	16
Net pre-tax restructuring costs (reversals)	24
Utilization and foreign exchange	8
Expected Costs	42
Remaining Costs	18
Current Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	10
Current Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	14
Current Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	16
Net pre-tax restructuring costs (reversals)	21
Utilization and foreign exchange	5
Current Year Actions [Member] | Facility Exit, Lease Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	0
Net pre-tax restructuring costs (reversals)	3
Utilization and foreign exchange	3
Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	22
Restructuring Reserve	103	$ 109
Net pre-tax restructuring costs (reversals)	22	242
Utilization and foreign exchange	28
Expected Costs	346
Remaining Costs	82
Prior Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	5
Prior Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	17
Prior Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	56	63
Net pre-tax restructuring costs (reversals)	15
Utilization and foreign exchange	22
Prior Year Actions [Member] | Facility Exit, Lease Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	47	46
Net pre-tax restructuring costs (reversals)	7
Utilization and foreign exchange	6
Two Years Prior Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	57
Otis [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	5
Otis [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	2
Expected Costs	5
Remaining Costs	3
Otis [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	3	48
Expected Costs	58
Remaining Costs	7
UTC Climate, Controls & Security [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	23
UTC Climate, Controls & Security [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	12
Expected Costs	21
Remaining Costs	9
UTC Climate, Controls & Security [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	6	45
Expected Costs	85
Remaining Costs	34
Pratt & Whitney [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	0	118
Expected Costs	118
Remaining Costs	0
UTC Aerospace Systems [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	23
UTC Aerospace Systems [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	9
Expected Costs	15
Remaining Costs	6
UTC Aerospace Systems [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (reversals)	13	$ 31
Expected Costs	85
Remaining Costs	41
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]
Net pre-tax restructuring costs (reversals)	(1)
Expected Costs	1
Remaining Costs	$ 0