Segment Information (Details 3) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue, Contract Type [Line Items]
Sales	$ 8,156	$ 8,085	$ 7,119	$ 6,735	$ 6,552	$ 6,569	$ 6,473	$ 6,410	$ 30,095	$ 26,004	$ 24,706
Concentration Risk, Percentage									100.00%	100.00%	100.00%
Operating Segments [Member] | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales									$ 13,096	$ 12,131	$ 10,853
Concentration Risk, Percentage									100.00%	100.00%	100.00%
Operating Segments [Member] | Innovation Systems
Revenue, Contract Type [Line Items]
Sales									$ 3,276	$ 0	$ 0
Concentration Risk, Percentage									100.00%	0.00%	0.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales									$ 11,709	$ 11,470	$ 11,161
Concentration Risk, Percentage									100.00%	100.00%	100.00%
Operating Segments [Member] | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales									$ 4,297	$ 4,687	$ 4,765
Concentration Risk, Percentage									100.00%	100.00%	100.00%
Cost-type
Revenue, Contract Type [Line Items]
Sales									$ 15,004	$ 14,197	$ 13,454
Concentration Risk, Percentage									50.00%	55.00%	54.00%
Cost-type | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales									$ 7,634	$ 7,193	$ 6,484
Concentration Risk, Percentage									59.00%	61.00%	61.00%
Cost-type | Innovation Systems
Revenue, Contract Type [Line Items]
Sales									$ 843	$ 0	$ 0
Concentration Risk, Percentage									27.00%	0.00%	0.00%
Cost-type | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales									$ 4,939	$ 5,311	$ 5,200
Concentration Risk, Percentage									47.00%	51.00%	51.00%
Cost-type | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales									$ 1,588	$ 1,693	$ 1,770
Concentration Risk, Percentage									46.00%	46.00%	46.00%
Fixed-price
Revenue, Contract Type [Line Items]
Sales									$ 15,091	$ 11,807	$ 11,252
Concentration Risk, Percentage									50.00%	45.00%	46.00%
Fixed-price | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales									$ 5,265	$ 4,643	$ 4,129
Concentration Risk, Percentage									41.00%	39.00%	39.00%
Fixed-price | Innovation Systems
Revenue, Contract Type [Line Items]
Sales									$ 2,306	$ 0	$ 0
Concentration Risk, Percentage									73.00%	0.00%	0.00%
Fixed-price | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales									$ 5,625	$ 5,205	$ 5,086
Concentration Risk, Percentage									53.00%	49.00%	49.00%
Fixed-price | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales									$ 1,895	$ 1,959	$ 2,037
Concentration Risk, Percentage									54.00%	54.00%	54.00%
Intersegment sales | Aerospace Systems [Member]
Revenue, Contract Type [Line Items]
Sales									$ 197	$ 295	$ 240
Intersegment sales | Innovation Systems
Revenue, Contract Type [Line Items]
Sales									127	0	0
Intersegment sales | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales									1,145	954	875
Intersegment sales | Technology Services [Member]
Revenue, Contract Type [Line Items]
Sales									$ 814	$ 1,035	$ 958