Segment Information (Unaudited) Sales by Contract Type (Details 3) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue, Contract Type [Line Items]
Sales	$ 9,083	$ 8,475	$ 26,587	$ 25,120
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Cost-type [Member]
Revenue, Contract Type [Line Items]
Sales	$ 4,496	$ 4,076	$ 13,082	$ 12,264
Concentration Risk, Percentage	49.00%	48.00%	49.00%	49.00%
Cost-type [Member] | Aeronautics Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,436	$ 1,326	$ 4,205	$ 3,950
Concentration Risk, Percentage	50.00%	48.00%	49.00%	48.00%
Cost-type [Member] | Defense Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 549	$ 641	$ 1,759	$ 1,896
Concentration Risk, Percentage	33.00%	37.00%	35.00%	37.00%
Cost-type [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 948	$ 797	$ 2,689	$ 2,502
Concentration Risk, Percentage	40.00%	38.00%	40.00%	39.00%
Cost-type [Member] | Space Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,563	$ 1,312	$ 4,429	$ 3,916
Concentration Risk, Percentage	72.00%	70.00%	72.00%	72.00%
Fixed-price [Member]
Revenue, Contract Type [Line Items]
Sales	$ 4,587	$ 4,399	$ 13,505	$ 12,856
Concentration Risk, Percentage	51.00%	52.00%	51.00%	51.00%
Fixed-price [Member] | Aeronautics Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,448	$ 1,417	$ 4,392	$ 4,284
Concentration Risk, Percentage	50.00%	52.00%	51.00%	52.00%
Fixed-price [Member] | Defense Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,119	$ 1,111	$ 3,325	$ 3,209
Concentration Risk, Percentage	67.00%	63.00%	65.00%	63.00%
Fixed-price [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,410	$ 1,322	$ 4,102	$ 3,870
Concentration Risk, Percentage	60.00%	62.00%	60.00%	61.00%
Fixed-price [Member] | Space Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 610	$ 549	$ 1,686	$ 1,493
Concentration Risk, Percentage	28.00%	30.00%	28.00%	28.00%
Intersegment sales | Aeronautics Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 30	$ 27	$ 85	$ 75
Intersegment sales | Defense Systems [Member]
Revenue, Contract Type [Line Items]
Sales	191	179	542	510
Intersegment sales | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	193	191	553	552
Intersegment sales | Space Systems [Member]
Revenue, Contract Type [Line Items]
Sales	25	24	79	65
Operating Segments [Member] | Aeronautics Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 2,914	$ 2,770	$ 8,682	$ 8,309
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Operating Segments [Member] | Defense Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 1,859	$ 1,931	$ 5,626	$ 5,615
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 2,551	$ 2,310	$ 7,344	$ 6,924
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Operating Segments [Member] | Space Systems [Member]
Revenue, Contract Type [Line Items]
Sales	$ 2,198	$ 1,885	$ 6,194	$ 5,474
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%