Segment Information (Unaudited) Sales by Geographic Location (Details 4) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue, Geographic Location [Line Items]
Sales	$ 9,157	$ 8,620
Concentration Risk, Percentage	100.00%	100.00%
United States
Revenue, Geographic Location [Line Items]
Sales	$ 7,799	$ 7,285
Concentration Risk, Percentage	85.00%	85.00%
United States | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,547	$ 2,373
Concentration Risk, Percentage	87.00%	84.00%
United States | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,026	$ 1,370
Concentration Risk, Percentage	75.00%	80.00%
United States | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,850	$ 1,688
Concentration Risk, Percentage	79.00%	78.00%
United States | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,376	$ 1,854
Concentration Risk, Percentage	95.00%	97.00%
Asia/Pacific
Revenue, Geographic Location [Line Items]
Sales	$ 558	$ 470
Concentration Risk, Percentage	6.00%	5.00%
Asia/Pacific | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 279	$ 207
Concentration Risk, Percentage	9.00%	8.00%
Asia/Pacific | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 103	$ 82
Concentration Risk, Percentage	7.00%	5.00%
Asia/Pacific | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 160	$ 176
Concentration Risk, Percentage	7.00%	8.00%
Asia/Pacific | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 16	$ 5
Concentration Risk, Percentage	1.00%	0.00%
Europe
Revenue, Geographic Location [Line Items]
Sales	$ 533	$ 520
Concentration Risk, Percentage	6.00%	6.00%
Europe | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 100	$ 166
Concentration Risk, Percentage	3.00%	6.00%
Europe | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 76	$ 70
Concentration Risk, Percentage	6.00%	4.00%
Europe | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 269	$ 225
Concentration Risk, Percentage	11.00%	10.00%
Europe | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 88	$ 59
Concentration Risk, Percentage	4.00%	3.00%
All other
Revenue, Geographic Location [Line Items]
Sales	$ 267	$ 345
Concentration Risk, Percentage	3.00%	4.00%
All other | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 20	$ 71
Concentration Risk, Percentage	1.00%	2.00%
All other | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 172	$ 188
Concentration Risk, Percentage	12.00%	11.00%
All other | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 73	$ 82
Concentration Risk, Percentage	3.00%	4.00%
All other | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2	$ 4
Concentration Risk, Percentage	0.00%	0.00%
Intersegment sales | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 44	$ 26
Intersegment sales | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	185	171
Intersegment sales | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	237	176
Intersegment sales | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	39	26
Operating Segments [Member] | Aeronautics Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,990	$ 2,843
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Defense Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,562	$ 1,881
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,589	$ 2,347
Concentration Risk, Percentage	100.00%	100.00%
Operating Segments [Member] | Space Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,521	$ 1,948
Concentration Risk, Percentage	100.00%	100.00%