Segment Information (Unaudited) (Details 4) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue, Geographic Location [Line Items]
Sales	$ 8,475	$ 8,085	$ 25,120	$ 21,939
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
United States
Revenue, Geographic Location [Line Items]
Sales	$ 7,270	$ 6,981	$ 21,397	$ 18,845
Concentration Risk, Percentage	86.00%	86.00%	85.00%	86.00%
United States | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 3,050	$ 2,970	$ 9,054	$ 8,757
Concentration Risk, Percentage	90.00%	92.00%	89.00%	90.00%
United States | Innovation Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,262	$ 1,105	$ 3,570	$ 1,401
Concentration Risk, Percentage	85.00%	80.00%	84.00%	79.00%
United States | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 2,292	$ 2,253	$ 6,880	$ 6,666
Concentration Risk, Percentage	85.00%	86.00%	85.00%	85.00%
United States | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 666	$ 653	$ 1,893	$ 2,021
Concentration Risk, Percentage	76.00%	78.00%	75.00%	77.00%
Asia/Pacific
Revenue, Geographic Location [Line Items]
Sales	$ 390	$ 446	$ 1,342	$ 1,229
Concentration Risk, Percentage	5.00%	6.00%	5.00%	6.00%
Asia/Pacific | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 173	$ 121	$ 632	$ 499
Concentration Risk, Percentage	5.00%	4.00%	6.00%	5.00%
Asia/Pacific | Innovation Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 30	$ 72	$ 123	$ 96
Concentration Risk, Percentage	2.00%	5.00%	3.00%	6.00%
Asia/Pacific | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 143	$ 208	$ 443	$ 521
Concentration Risk, Percentage	5.00%	8.00%	5.00%	7.00%
Asia/Pacific | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 44	$ 45	$ 144	$ 113
Concentration Risk, Percentage	5.00%	5.00%	6.00%	4.00%
All other
Revenue, Geographic Location [Line Items]
Sales	$ 815	$ 658	$ 2,381	$ 1,865
Concentration Risk, Percentage	9.00%	8.00%	10.00%	8.00%
All other | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 180	$ 149	$ 505	$ 491
Concentration Risk, Percentage	5.00%	4.00%	5.00%	5.00%
All other | Innovation Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 198	$ 201	$ 579	$ 268
Concentration Risk, Percentage	13.00%	15.00%	13.00%	15.00%
All other | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 273	$ 170	$ 799	$ 623
Concentration Risk, Percentage	10.00%	6.00%	10.00%	8.00%
All other | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 164	$ 138	$ 498	$ 483
Concentration Risk, Percentage	19.00%	17.00%	19.00%	19.00%
Intersegment sales | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 55	$ 42	$ 153	$ 152
Intersegment sales | Innovation Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	94	37	248	50
Intersegment sales | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	321	280	921	858
Intersegment sales | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	193	204	553	615
Operating Segments [Member] | Aerospace Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 3,458	$ 3,282	$ 10,344	$ 9,899
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Operating Segments [Member] | Innovation Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,584	$ 1,415	$ 4,520	$ 1,815
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 3,029	$ 2,911	$ 9,043	$ 8,668
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Operating Segments [Member] | Technology Services [Member]
Revenue, Geographic Location [Line Items]
Sales	$ 1,067	$ 1,040	$ 3,088	$ 3,232
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%