Restructuring and Other Costs (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				$ 244
Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				119
Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				125
Otis [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				44
Carrier [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				97
Pratt & Whitney [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				17
Collins Aerospace Systems [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				83
Eliminations and other [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				3
Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	$ 43			158
Utilization, foreign exchange and other costs	(40)			(87)
Restructuring Reserve	71	$ 68		71
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	424			424
Cost Incurred	43	42	$ 73
Remaining Costs	266			266
Current Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	35			145
Utilization, foreign exchange and other costs	(33)			(86)
Restructuring Reserve	59	57		59
Current Year Actions [Member] | Facility Exit, Lease Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	8			13
Utilization, foreign exchange and other costs	(7)			(1)
Restructuring Reserve	12	11		12
Current Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				62
Current Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				96
Current Year Actions [Member] | Otis [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	43			43
Cost Incurred	3	14	19
Remaining Costs	7			7
Current Year Actions [Member] | Carrier [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	113			113
Cost Incurred	32	24	25
Remaining Costs	32			32
Current Year Actions [Member] | Pratt & Whitney [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	158			158
Cost Incurred	0	3	14
Remaining Costs	141			141
Current Year Actions [Member] | Collins Aerospace Systems [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	107			107
Cost Incurred	7	0	14
Remaining Costs	86			86
Current Year Actions [Member] | Eliminations and other [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	3			3
Cost Incurred	(1)	1	1
Remaining Costs	0			0
Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	5			44
Utilization, foreign exchange and other costs	(24)			(144)
Restructuring Reserve	38	57		38	$ 138
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	259			259
Cost Incurred	5	16	23		207
Remaining Costs	8			8
Prior Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	1			36
Utilization, foreign exchange and other costs	(19)			(121)
Restructuring Reserve	30	48		30	115
Prior Year Actions [Member] | Facility Exit, Lease Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	4			8
Utilization, foreign exchange and other costs	(5)			(23)
Restructuring Reserve	8	9		8	23
Prior Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				21
Prior Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				23
Prior Year Actions [Member] | Otis [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	55			55
Cost Incurred	0	1	5		48
Remaining Costs	1			1
Prior Year Actions [Member] | Carrier [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	82			82
Cost Incurred	2	6	7		64
Remaining Costs	3			3
Prior Year Actions [Member] | Pratt & Whitney [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	3			3
Cost Incurred	0	0	0		3
Remaining Costs	0			0
Prior Year Actions [Member] | Collins Aerospace Systems [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	113			113
Cost Incurred	3	9	11		87
Remaining Costs	3			3
Prior Year Actions [Member] | Eliminations and other [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	6			6
Cost Incurred	0	$ 0	$ 0		$ 5
Remaining Costs	1			1
Two Years Prior Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs				42
Restructuring Reserve	$ 73			$ 73