Inventoried Costs, Net (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Production costs of contracts in process	$ 1,813	$ 1,574
General and administrative expenses	266	249
Inventoried costs	2,079	1,823
Progress and performance-based payments received	(1,396)	(1,107)
Inventoried costs, net of progress payments	683	716
Product inventory	97	100
Inventory, Net	$ 780	$ 816