Restructuring and Other Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs			$ 178
Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs			82
Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs			96
Otis [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs			40
Carrier [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs			63
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			56
Eliminations and other [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs			2
Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	$ 42		115
Utilization, foreign exchange and other costs	(42)		(47)
Restructuring Reserve	68	$ 68	68
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	188		188
Cost Incurred	42	73
Remaining Costs	73		73
Current Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	42		110
Utilization, foreign exchange and other costs	(38)		(53)
Restructuring Reserve	57	53	57
Current Year Actions [Member] | Facility Exit, Lease Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	0		5
Utilization, foreign exchange and other costs	(4)		6
Restructuring Reserve	11	15	11
Current Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs			43
Current Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs			72
Current Year Actions [Member] | Otis [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	48		48
Cost Incurred	14	19
Remaining Costs	15		15
Current Year Actions [Member] | Carrier [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	77		77
Cost Incurred	24	25
Remaining Costs	28		28
Current Year Actions [Member] | Pratt & Whitney [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	17		17
Cost Incurred	3	14
Remaining Costs	0		0
Current Year Actions [Member] | Collins Aerospace Systems [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	44		44
Cost Incurred	0	14
Remaining Costs	30		30
Current Year Actions [Member] | Eliminations and other [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	2		2
Cost Incurred	1	1
Remaining Costs	0		0
Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	16		39
Utilization, foreign exchange and other costs	(30)		(120)
Restructuring Reserve	57	71	57	$ 138
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	266		266
Cost Incurred	16	23		207
Remaining Costs	20		20
Prior Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	14		35
Utilization, foreign exchange and other costs	(28)		(102)
Restructuring Reserve	48	62	48	115
Prior Year Actions [Member] | Facility Exit, Lease Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs	2		4
Utilization, foreign exchange and other costs	(2)		(18)
Restructuring Reserve	9	9	9	23
Prior Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs			20
Prior Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs			19
Prior Year Actions [Member] | Otis [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	58		58
Cost Incurred	1	5		48
Remaining Costs	4		4
Prior Year Actions [Member] | Carrier [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	85		85
Cost Incurred	6	7		64
Remaining Costs	8		8
Prior Year Actions [Member] | Pratt & Whitney [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	3		3
Cost Incurred	0	0		3
Remaining Costs	0		0
Prior Year Actions [Member] | Collins Aerospace Systems [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	115		115
Cost Incurred	9	11		87
Remaining Costs	8		8
Prior Year Actions [Member] | Eliminations and other [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Expected Costs	5		5
Cost Incurred	0	$ 0		$ 5
Remaining Costs	0		0
Two Years Prior Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs			24
Restructuring Reserve	$ 74		$ 74