Segment Information (Unaudited) Sales by Geographic Location (Details 4) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue, Geographic Location [Line Items]
Sales	$ 9,083	$ 8,475	$ 26,587	$ 25,120
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
United States
Revenue, Geographic Location [Line Items]
Sales	$ 7,840	$ 7,270	$ 22,748	$ 21,397
Concentration Risk, Percentage	86.00%	86.00%	86.00%	85.00%
United States | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,502	$ 2,353	$ 7,364	$ 6,970
Concentration Risk, Percentage	87.00%	86.00%	86.00%	85.00%
United States | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,361	$ 1,405	$ 4,121	$ 4,030
Concentration Risk, Percentage	82.00%	80.00%	81.00%	79.00%
United States | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,903	$ 1,712	$ 5,385	$ 5,124
Concentration Risk, Percentage	81.00%	81.00%	79.00%	81.00%
United States | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,074	$ 1,800	$ 5,878	$ 5,273
Concentration Risk, Percentage	96.00%	97.00%	96.00%	98.00%
Asia/Pacific
Revenue, Geographic Location [Line Items]
Sales	$ 447	$ 390	$ 1,422	$ 1,342
Concentration Risk, Percentage	5.00%	5.00%	5.00%	5.00%
Asia/Pacific | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 217	$ 177	$ 626	$ 625
Concentration Risk, Percentage	7.00%	6.00%	7.00%	7.00%
Asia/Pacific | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 103	$ 78	$ 292	$ 291
Concentration Risk, Percentage	6.00%	5.00%	6.00%	6.00%
Asia/Pacific | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 122	$ 135	$ 489	$ 412
Concentration Risk, Percentage	5.00%	6.00%	7.00%	6.00%
Asia/Pacific | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 5	$ 0	$ 15	$ 14
Concentration Risk, Percentage	0.00%	0.00%	0.00%	0.00%
All other
Revenue, Geographic Location [Line Items]
Sales	$ 796	$ 815	$ 2,417	$ 2,381
Concentration Risk, Percentage	9.00%	9.00%	9.00%	10.00%
All other | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 165	$ 213	$ 607	$ 639
Concentration Risk, Percentage	6.00%	8.00%	7.00%	8.00%
All other | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 204	$ 269	$ 671	$ 784
Concentration Risk, Percentage	12.00%	15.00%	13.00%	15.00%
All other | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 333	$ 272	$ 917	$ 836
Concentration Risk, Percentage	14.00%	13.00%	14.00%	13.00%
All other | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 94	$ 61	$ 222	$ 122
Concentration Risk, Percentage	4.00%	3.00%	4.00%	2.00%
Intersegment sales | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 30	$ 27	$ 85	$ 75
Intersegment sales | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	191	179	542	510
Intersegment sales | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	193	191	553	552
Intersegment sales | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	25	24	79	65
Operating Segments [Member] | Aeronautics Systems [Member]
Revenue, Geographic Location [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, Geographic Location [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, Geographic Location [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, Geographic Location [Line Items]
Sales	$ 2,198	$ 1,885	$ 6,194	$ 5,474
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%