Receivables, net, Contract Assets and Contract Liabilities - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
U.S. government receivables	$ 1,200
Receivables from other governments and commercial customers	1,978	$ 2,337
Contract assets, progress payments	39,700	33,000
Increase in contract assets	451	(378)	$ 1,480
Impairment loss	0	0
Increase in contract liability	491	563	(537)
Liability, revenue recognized	4,000	$ 3,900	$ 3,900
Other Governments and Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables from other governments and commercial customers	$ 735