Contract Asset and Liability (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Revenue from contract with customer [Line Items]
Contract assets	$ 10,899		$ 10,899		$ 9,931
Contract liabilities	(12,543)		(12,543)		(12,889)
Net contract liabilities	(1,644)		(1,644)		(2,958)
Contract with Customer, Asset, Change			968
Contract with Customer, Liability, Change			(346)
Contract liability write-off related a contract termination			364
Contract with Customer, Liability, Revenue Recognized	960	$ 480	3,686	$ 2,288
Advances received to date on contracts related to precision guided munitions to certain Middle Eastern customers pending U.S. government approval	440		440
Contract with Customer, Asset, Allowance for Credit Loss	$ 250		$ 250		$ 177