Receivables, net, Contract Assets and Contract Liabilities - Narrative (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
U.S. government receivables	$ 1,900
Receivables from other governments and commercial customers	2,444	$ 2,265
Contract assets, progress payments	30,200	19,900
Increase in contract assets	1,480	(390)	$ 1,246
Impairment loss	0	0
Increase (decrease) in contract liability	(537)	353	(163)
Liability, revenue recognized	3,900	$ 3,300	$ 3,700
Other Governments and Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables from other governments and commercial customers	$ 578