Segment Information (Unaudited) (Details 3) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue, Contract Type [Line Items]
Sales	$ 8,085	$ 6,569	$ 21,939	$ 19,452
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Cost-type [Member]
Revenue, Contract Type [Line Items]
Sales	$ 3,958	$ 3,532	$ 11,201	$ 10,717
Concentration Risk, Percentage	49.00%	54.00%	51.00%	55.00%
Cost-type [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,953	$ 1,782	$ 5,789	$ 5,449
Concentration Risk, Percentage	60.00%	58.00%	59.00%	61.00%
Cost-type [Member] | Innovation Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 373	$ 0	$ 472	$ 0
Concentration Risk, Percentage	27.00%	0.00%	27.00%	0.00%
Cost-type [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,259	$ 1,315	$ 3,745	$ 3,984
Concentration Risk, Percentage	48.00%	51.00%	48.00%	51.00%
Cost-type [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	$ 373	$ 435	$ 1,195	$ 1,284
Concentration Risk, Percentage	45.00%	48.00%	46.00%	46.00%
Fixed-price [Member]
Revenue, Contract Type [Line Items]
Sales	$ 4,127	$ 3,037	$ 10,738	$ 8,735
Concentration Risk, Percentage	51.00%	46.00%	49.00%	45.00%
Fixed-price [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,287	$ 1,273	$ 3,958	$ 3,434
Concentration Risk, Percentage	40.00%	42.00%	41.00%	39.00%
Fixed-price [Member] | Innovation Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,005	$ 0	$ 1,293	$ 0
Concentration Risk, Percentage	73.00%	0.00%	73.00%	0.00%
Fixed-price [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,372	$ 1,288	$ 4,065	$ 3,793
Concentration Risk, Percentage	52.00%	49.00%	52.00%	49.00%
Fixed-price [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	$ 463	$ 476	$ 1,422	$ 1,508
Concentration Risk, Percentage	55.00%	52.00%	54.00%	54.00%
Intersegment Eliminations [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 42	$ 70	$ 152	$ 229
Intersegment Eliminations [Member] | Innovation Systems [Member]
Revenue, Contract Type [Line Items]
Sales	37	0	50	0
Intersegment Eliminations [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	280	233	858	718
Intersegment Eliminations [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	204	272	615	743
Operating Segments [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 3,282	$ 3,125	$ 9,899	$ 9,112
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Operating Segments [Member] | Innovation Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,415	$ 0	$ 1,815	$ 0
Concentration Risk, Percentage	100.00%	0.00%	100.00%	0.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 2,911	$ 2,836	$ 8,668	$ 8,495
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Operating Segments [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,040	$ 1,183	$ 3,232	$ 3,535
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%