Segment Information (Unaudited) Sales by Geographic Location (Details 4) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue, Geographic Location [Line Items]
Sales	$ 8,620	$ 8,189
Concentration Risk, Percentage	100.00%	100.00%
United States
Revenue, Geographic Location [Line Items]
Sales	$ 7,285	$ 6,972
Concentration Risk, Percentage	85.00%	85.00%
United States | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,373	$ 2,359
Concentration Risk, Percentage	84.00%	85.00%
United States | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,370	$ 1,238
Concentration Risk, Percentage	80.00%	77.00%
United States | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,688	$ 1,637
Concentration Risk, Percentage	78.00%	81.00%
United States | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,854	$ 1,738
Concentration Risk, Percentage	97.00%	98.00%
Asia/Pacific
Revenue, Geographic Location [Line Items]
Sales	$ 470	$ 468
Concentration Risk, Percentage	5.00%	6.00%
Asia/Pacific | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 207	$ 233
Concentration Risk, Percentage	8.00%	8.00%
Asia/Pacific | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 82	$ 88
Concentration Risk, Percentage	5.00%	6.00%
Asia/Pacific | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 176	$ 135
Concentration Risk, Percentage	8.00%	7.00%
Asia/Pacific | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 5	$ 12
Concentration Risk, Percentage	0.00%	0.00%
All other
Revenue, Geographic Location [Line Items]
Sales	$ 865	$ 749
Concentration Risk, Percentage	10.00%	9.00%
All other | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 237	$ 202
Concentration Risk, Percentage	8.00%	7.00%
All other | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 258	$ 275
Concentration Risk, Percentage	15.00%	17.00%
All other | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 307	$ 241
Concentration Risk, Percentage	14.00%	12.00%
All other | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 63	$ 31
Concentration Risk, Percentage	3.00%	2.00%
Intersegment sales | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 26	$ 24
Intersegment sales | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	171	167
Intersegment sales | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	176	197
Intersegment sales | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	26	20
Operating Segments [Member] | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,843	$ 2,818
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,881	$ 1,768
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,347	$ 2,210
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,948	$ 1,801
Concentration Risk, Percentage	100.00%	100.00%