Segment Information (Unaudited) (Details 2) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue, Major Customer [Line Items]
Sales	$ 6,735	$ 6,410
Concentration Risk, Percentage	100.00%	100.00%
US Government [Member]
Revenue, Major Customer [Line Items]
Sales	$ 5,700	$ 5,375
Concentration Risk, Percentage	85.00%	84.00%
US Government [Member] | Aerospace Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 2,908	$ 2,553
Concentration Risk, Percentage	89.00%	86.00%
US Government [Member] | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 2,190	$ 2,186
Concentration Risk, Percentage	76.00%	78.00%
US Government [Member] | Technology Services [Member]
Revenue, Major Customer [Line Items]
Sales	$ 602	$ 636
Concentration Risk, Percentage	53.00%	53.00%
International Customer [Member]
Revenue, Major Customer [Line Items]
Sales	$ 870	$ 872
Concentration Risk, Percentage	13.00%	14.00%
International Customer [Member] | Aerospace Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 271	$ 309
Concentration Risk, Percentage	8.00%	10.00%
International Customer [Member] | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 379	$ 354
Concentration Risk, Percentage	13.00%	13.00%
International Customer [Member] | Technology Services [Member]
Revenue, Major Customer [Line Items]
Sales	$ 220	$ 209
Concentration Risk, Percentage	19.00%	18.00%
Other Customers [Member]
Revenue, Major Customer [Line Items]
Sales	$ 165	$ 163
Concentration Risk, Percentage	2.00%	2.00%
Other Customers [Member] | Aerospace Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 42	$ 38
Concentration Risk, Percentage	1.00%	1.00%
Other Customers [Member] | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 30	$ 21
Concentration Risk, Percentage	1.00%	1.00%
Other Customers [Member] | Technology Services [Member]
Revenue, Major Customer [Line Items]
Sales	$ 93	$ 104
Concentration Risk, Percentage	8.00%	9.00%
Intersegment Eliminations [Member] | Aerospace Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 59	$ 84
Concentration Risk, Percentage	2.00%	3.00%
Intersegment Eliminations [Member] | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 284	$ 239
Concentration Risk, Percentage	10.00%	8.00%
Intersegment Eliminations [Member] | Technology Services [Member]
Revenue, Major Customer [Line Items]
Sales	$ 229	$ 241
Concentration Risk, Percentage	20.00%	20.00%
Operating Segments [Member] | Aerospace Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 3,280	$ 2,984
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales	$ 2,883	$ 2,800
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Technology Services [Member]
Revenue, Major Customer [Line Items]
Sales	$ 1,144	$ 1,190
Concentration Risk, Percentage	100.00%	100.00%