Segment Information (Unaudited) (Details 4) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue, Geographic Location [Line Items]
Sales	$ 7,119	$ 6,473	$ 13,854	$ 12,883
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
United States
Revenue, Geographic Location [Line Items]
Sales	$ 5,999	$ 5,681	$ 11,864	$ 11,220
Concentration Risk, Percentage	84.00%	88.00%	85.00%	87.00%
United States | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,837	$ 2,656	$ 5,787	$ 5,247
Concentration Risk, Percentage	86.00%	91.00%	89.00%	90.00%
United States | Innovation Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 296	$ 0	$ 296	$ 0
Concentration Risk, Percentage	77.00%	0.00%	77.00%	0.00%
United States | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,193	$ 2,261	$ 4,413	$ 4,468
Concentration Risk, Percentage	85.00%	86.00%	85.00%	86.00%
United States | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 673	$ 764	$ 1,368	$ 1,505
Concentration Risk, Percentage	78.00%	82.00%	77.00%	80.00%
Asia/Pacific
Revenue, Geographic Location [Line Items]
Sales	$ 469	$ 340	$ 783	$ 728
Concentration Risk, Percentage	7.00%	5.00%	6.00%	6.00%
Asia/Pacific | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 249	$ 157	$ 378	$ 345
Concentration Risk, Percentage	8.00%	5.00%	6.00%	6.00%
Asia/Pacific | Innovation Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 24	$ 0	$ 24	$ 0
Concentration Risk, Percentage	6.00%	0.00%	6.00%	0.00%
Asia/Pacific | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 160	$ 155	$ 313	$ 309
Concentration Risk, Percentage	6.00%	6.00%	6.00%	6.00%
Asia/Pacific | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 36	$ 28	$ 68	$ 74
Concentration Risk, Percentage	4.00%	3.00%	4.00%	4.00%
All other (principally Europe and Middle East)
Revenue, Geographic Location [Line Items]
Sales	$ 651	$ 452	$ 1,207	$ 935
Concentration Risk, Percentage	9.00%	7.00%	9.00%	7.00%
All other (principally Europe and Middle East) | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 200	$ 115	$ 342	$ 236
Concentration Risk, Percentage	6.00%	4.00%	5.00%	4.00%
All other (principally Europe and Middle East) | Innovation Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 67	$ 0	$ 67	$ 0
Concentration Risk, Percentage	17.00%	0.00%	17.00%	0.00%
All other (principally Europe and Middle East) | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 227	$ 197	$ 453	$ 397
Concentration Risk, Percentage	9.00%	8.00%	9.00%	8.00%
All other (principally Europe and Middle East) | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 157	$ 140	$ 345	$ 302
Concentration Risk, Percentage	18.00%	15.00%	19.00%	16.00%
Intersegment Eliminations [Member] | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 51	$ 75	$ 110	$ 159
Intersegment Eliminations [Member] | Innovation Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	13	0	13	0
Intersegment Eliminations [Member] | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	294	246	578	485
Intersegment Eliminations [Member] | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	182	230	411	471
Operating Segments [Member] | Aerospace Systems [Member]
Revenue, Geographic Location [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, Geographic Location [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, Geographic Location [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, Geographic Location [Line Items]
Sales	$ 1,048	$ 1,162	$ 2,192	$ 2,352
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%