Restructuring Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	$ 777
Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	397
Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	371
Non-service pension (benefit) [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	9
Operating Expense
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	768
Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	770
Utilization and foreign exchange	(430)
Restructuring Reserve	340
Expected Costs	810
Restructuring cost incurred	(770)
Remaining Costs	40
Current Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	401
Current Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	360
Current Year Actions [Member] | Non-service pension (benefit) [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	9
Current Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	744
Utilization and foreign exchange	(410)
Restructuring Reserve	334
Current Year Actions [Member] | Facility Exit, Lease Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	26
Utilization and foreign exchange	(20)
Restructuring Reserve	6
Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	10
Utilization and foreign exchange	(46)
Restructuring Reserve	22	$ 58
Expected Costs	230
Restructuring cost incurred	(10)	(162)
Remaining Costs	58
Prior Year Actions [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	(2)
Prior Year Actions [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	12
Prior Year Actions [Member] | Severance [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	6
Utilization and foreign exchange	(41)
Restructuring Reserve	12	47
Prior Year Actions [Member] | Facility Exit, Lease Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	4
Utilization and foreign exchange	(5)
Restructuring Reserve	10	11
Two Years Prior Actions [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	(3)
Restructuring Reserve	45
Pratt and Whitney [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	183
Pratt and Whitney [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Expected Costs	205
Restructuring cost incurred	(205)
Remaining Costs	0
Pratt and Whitney [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Expected Costs	121
Restructuring cost incurred	12	(133)
Remaining Costs	0
Eliminations and other [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	234
Eliminations and other [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Expected Costs	232
Restructuring cost incurred	(232)
Remaining Costs	0
Eliminations and other [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Expected Costs	2
Restructuring cost incurred	0	(2)
Remaining Costs	0
Collins Aerospace Systems [Member]
Restructuring Cost and Reserve [Line Items]
Net pre-tax restructuring costs (benefit)	360
Collins Aerospace Systems [Member] | Current Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Expected Costs	373
Restructuring cost incurred	(333)
Remaining Costs	40
Collins Aerospace Systems [Member] | Prior Year Actions [Member]
Restructuring Cost and Reserve [Line Items]
Expected Costs	107
Restructuring cost incurred	(22)	$ (27)
Remaining Costs	$ 58