Segment Information (Unaudited) (Details 3) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue, Contract Type [Line Items]
Sales	$ 7,119	$ 6,473	$ 13,854	$ 12,883
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Cost-type [Member]
Revenue, Contract Type [Line Items]
Sales	$ 3,625	$ 3,597	$ 7,243	$ 7,185
Concentration Risk, Percentage	51.00%	56.00%	52.00%	56.00%
Cost-type [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,934	$ 1,840	$ 3,836	$ 3,667
Concentration Risk, Percentage	59.00%	63.00%	59.00%	63.00%
Cost-type [Member] | Innovation Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 99	$ 0	$ 99	$ 0
Concentration Risk, Percentage	26.00%	0.00%	26.00%	0.00%
Cost-type [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,207	$ 1,353	$ 2,486	$ 2,669
Concentration Risk, Percentage	47.00%	52.00%	48.00%	52.00%
Cost-type [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	$ 385	$ 404	$ 822	$ 849
Concentration Risk, Percentage	44.00%	43.00%	46.00%	45.00%
Fixed-price [Member]
Revenue, Contract Type [Line Items]
Sales	$ 3,494	$ 2,876	$ 6,611	$ 5,698
Concentration Risk, Percentage	49.00%	44.00%	48.00%	44.00%
Fixed-price [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,352	$ 1,088	$ 2,671	$ 2,161
Concentration Risk, Percentage	41.00%	37.00%	41.00%	37.00%
Fixed-price [Member] | Innovation Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 288	$ 0	$ 288	$ 0
Concentration Risk, Percentage	74.00%	0.00%	74.00%	0.00%
Fixed-price [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,373	$ 1,260	$ 2,693	$ 2,505
Concentration Risk, Percentage	53.00%	48.00%	52.00%	48.00%
Fixed-price [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	$ 481	$ 528	$ 959	$ 1,032
Concentration Risk, Percentage	56.00%	57.00%	54.00%	55.00%
Intersegment Eliminations [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 51	$ 75	$ 110	$ 159
Intersegment Eliminations [Member] | Innovation Systems [Member]
Revenue, Contract Type [Line Items]
Sales	13	0	13	0
Intersegment Eliminations [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	294	246	578	485
Intersegment Eliminations [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	182	230	411	471
Operating Segments [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 3,337	$ 3,003	$ 6,617	$ 5,987
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Operating Segments [Member] | Innovation Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 400	$ 0	$ 400	$ 0
Concentration Risk, Percentage	100.00%	0.00%	100.00%	0.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 2,874	$ 2,859	$ 5,757	$ 5,659
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Operating Segments [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,048	$ 1,162	$ 2,192	$ 2,352
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%