Segment Information (Unaudited) (Details 3) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue, Contract Type [Line Items]
Sales	$ 6,735	$ 6,410
Concentration Risk, Percentage	100.00%	100.00%
Cost-type [Member]
Revenue, Contract Type [Line Items]
Sales	$ 3,618	$ 3,588
Concentration Risk, Percentage	54.00%	56.00%
Cost-type [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,902	$ 1,827
Concentration Risk, Percentage	59.00%	63.00%
Cost-type [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,279	$ 1,316
Concentration Risk, Percentage	49.00%	51.00%
Cost-type [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	$ 437	$ 445
Concentration Risk, Percentage	48.00%	47.00%
Fixed-price [Member]
Revenue, Contract Type [Line Items]
Sales	$ 3,117	$ 2,822
Concentration Risk, Percentage	46.00%	44.00%
Fixed-price [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,319	$ 1,073
Concentration Risk, Percentage	41.00%	37.00%
Fixed-price [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,320	$ 1,245
Concentration Risk, Percentage	51.00%	49.00%
Fixed-price [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	$ 478	$ 504
Concentration Risk, Percentage	52.00%	53.00%
Intersegment Eliminations [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 59	$ 84
Intersegment Eliminations [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	284	239
Intersegment Eliminations [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	229	241
Operating Segments [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 3,280	$ 2,984
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 2,883	$ 2,800
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,144	$ 1,190
Concentration Risk, Percentage	100.00%	100.00%