Segment Information (Unaudited) (Details 4) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue, Geographic Location [Line Items]
Sales	$ 6,735	$ 6,410
Concentration Risk, Percentage	100.00%	100.00%
United States
Revenue, Geographic Location [Line Items]
Sales	$ 5,865	$ 5,539
Concentration Risk, Percentage	87.00%	86.00%
United States | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,950	$ 2,591
Concentration Risk, Percentage	92.00%	89.00%
United States | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,220	$ 2,207
Concentration Risk, Percentage	85.00%	86.00%
United States | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 695	$ 741
Concentration Risk, Percentage	76.00%	78.00%
Asia/Pacific
Revenue, Geographic Location [Line Items]
Sales	$ 314	$ 388
Concentration Risk, Percentage	5.00%	6.00%
Asia/Pacific | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 129	$ 188
Concentration Risk, Percentage	4.00%	7.00%
Asia/Pacific | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 153	$ 154
Concentration Risk, Percentage	6.00%	6.00%
Asia/Pacific | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 32	$ 46
Concentration Risk, Percentage	3.00%	5.00%
All other (principally Europe and Middle East)
Revenue, Geographic Location [Line Items]
Sales	$ 556	$ 483
Concentration Risk, Percentage	8.00%	8.00%
All other (principally Europe and Middle East) | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 142	$ 121
Concentration Risk, Percentage	4.00%	4.00%
All other (principally Europe and Middle East) | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 226	$ 200
Concentration Risk, Percentage	9.00%	8.00%
All other (principally Europe and Middle East) | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 188	$ 162
Concentration Risk, Percentage	21.00%	17.00%
Intersegment Eliminations [Member] | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 59	$ 84
Intersegment Eliminations [Member] | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	284	239
Intersegment Eliminations [Member] | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	229	241
Operating Segments [Member] | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 3,280	$ 2,984
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,883	$ 2,800
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,144	$ 1,190
Concentration Risk, Percentage	100.00%	100.00%