Restructuring and Other Costs (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	$ 62
Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	31
Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	31
Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	28
Severance Costs	28
Restructuring and Related Cost, Expected Cost	108
Restructuring and Related Cost, Expected Cost Remaining	80
Current Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	13
Current Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	15
Current Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Translation and Other Adjustment	3
Restructuring Reserve	25
Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	29	$ 326
Severance Costs	21
Restructuring Reserve, Translation and Other Adjustment	71
Facility Exit, Lease Termination and Other Costs	8
Restructuring Reserve	164	206
Restructuring and Related Cost, Expected Cost	527
Restructuring and Related Cost, Expected Cost Remaining	172
Prior Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	15
Prior Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	14
Prior Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Translation and Other Adjustment	63
Restructuring Reserve	141	183
Prior Year Actions [Member] | Facility Exit, Lease Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Translation and Other Adjustment	8
Restructuring Reserve	23	23
Two Years Prior Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	83
Otis [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	15
Otis [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	10
Restructuring and Related Cost, Expected Cost	14
Restructuring and Related Cost, Expected Cost Remaining	4
Otis [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	5	35
Restructuring and Related Cost, Expected Cost	54
Restructuring and Related Cost, Expected Cost Remaining	14
UTC Climate, Controls & Security [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	28
UTC Climate, Controls & Security [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	13
Restructuring and Related Cost, Expected Cost	21
Restructuring and Related Cost, Expected Cost Remaining	8
UTC Climate, Controls & Security [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	14	83
Restructuring and Related Cost, Expected Cost	207
Restructuring and Related Cost, Expected Cost Remaining	110
Pratt & Whitney [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	5
Pratt & Whitney [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	1	82
Restructuring and Related Cost, Expected Cost	100
Restructuring and Related Cost, Expected Cost Remaining	17
UTC Aerospace Systems [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	13
UTC Aerospace Systems [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	5
Restructuring and Related Cost, Expected Cost	73
Restructuring and Related Cost, Expected Cost Remaining	68
UTC Aerospace Systems [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	8	105
Restructuring and Related Cost, Expected Cost	144
Restructuring and Related Cost, Expected Cost Remaining	31
Eliminations and other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	1
Eliminations and other [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Expense	1	$ 21
Restructuring and Related Cost, Expected Cost	22
Restructuring and Related Cost, Expected Cost Remaining	$ 0