Receivables, Loans, Notes Receivable, and Others (Schedule of Accounts Receivable, net) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounts Notes And Loans Receivable [Line Items]
U.S. government contracts (including foreign military sales)	$ 1,039	$ 551
Allowance for expected credit losses	(546)	(254)
Accounts receivable, net	9,254	8,743
Other Customer
Accounts Notes And Loans Receivable [Line Items]
Accounts Receivable, Other Customers	$ 8,761	$ 8,446