Commercial Aerospace Industry Assets and Commitments (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Goodwill impairment	$ 3,200	$ 3,183	$ 0	$ 0
Accounts receivable, net		9,254	8,743
Contract assets		9,931	4,462
Customer financing assets		3,144	3,463
Other Commitment		11,000
Collins Aerospace Systems [Member]
Accounts Notes And Loans Receivable [Line Items]
Goodwill impairment	$ 3,200	3,183
Commercial Aerospace [Member]
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, net		7,239	7,560
Contract assets		2,559	2,741
Customer financing assets		3,160	3,476
Contract fulfillment costs		1,773	1,361
Commercial aerospace guarantees (net of reserves and collaboration partners’ share) (Note 18)		174	184
Other Commitment		$ 8,515	$ 9,708