Segment Information (Details 2) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue, Major Customer [Line Items]
Sales	$ 8,156	$ 8,085	$ 7,119	$ 6,735	$ 6,552	$ 6,569	$ 6,473	$ 6,410	$ 30,095	$ 26,004	$ 24,706
Concentration Risk, Percentage									100.00%	100.00%	100.00%
US Government
Revenue, Major Customer [Line Items]
Sales									$ 24,796	$ 21,969	$ 20,736
Concentration Risk, Percentage									82.00%	85.00%	84.00%
US Government | Aerospace Systems [Member]
Revenue, Major Customer [Line Items]
Sales									$ 11,380	$ 10,521	$ 9,277
Concentration Risk, Percentage									87.00%	87.00%	86.00%
US Government | Innovation Systems
Revenue, Major Customer [Line Items]
Sales									$ 2,241	$ 0	$ 0
Concentration Risk, Percentage									68.00%	0.00%	0.00%
US Government | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales									$ 8,803	$ 8,876	$ 8,737
Concentration Risk, Percentage									75.00%	77.00%	78.00%
US Government | Technology Services [Member]
Revenue, Major Customer [Line Items]
Sales									$ 2,372	$ 2,572	$ 2,722
Concentration Risk, Percentage									55.00%	55.00%	57.00%
International
Revenue, Major Customer [Line Items]
Sales									$ 4,434	$ 3,452	$ 3,295
Concentration Risk, Percentage									15.00%	13.00%	13.00%
International | Aerospace Systems [Member]
Revenue, Major Customer [Line Items]
Sales									$ 1,371	$ 1,160	$ 1,192
Concentration Risk, Percentage									10.00%	10.00%	11.00%
International | Innovation Systems
Revenue, Major Customer [Line Items]
Sales									$ 615	$ 0	$ 0
Concentration Risk, Percentage									19.00%	0.00%	0.00%
International | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales									$ 1,647	$ 1,540	$ 1,416
Concentration Risk, Percentage									14.00%	14.00%	13.00%
International | Technology Services [Member]
Revenue, Major Customer [Line Items]
Sales									$ 801	$ 752	$ 687
Concentration Risk, Percentage									19.00%	16.00%	15.00%
Other Customers
Revenue, Major Customer [Line Items]
Sales									$ 865	$ 583	$ 675
Concentration Risk, Percentage									3.00%	2.00%	3.00%
Other Customers | Aerospace Systems [Member]
Revenue, Major Customer [Line Items]
Sales									$ 148	$ 155	$ 144
Concentration Risk, Percentage									1.00%	1.00%	1.00%
Other Customers | Innovation Systems
Revenue, Major Customer [Line Items]
Sales									$ 293	$ 0	$ 0
Concentration Risk, Percentage									9.00%	0.00%	0.00%
Other Customers | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales									$ 114	$ 100	$ 133
Concentration Risk, Percentage									1.00%	1.00%	1.00%
Other Customers | Technology Services [Member]
Revenue, Major Customer [Line Items]
Sales									$ 310	$ 328	$ 398
Concentration Risk, Percentage									7.00%	7.00%	8.00%
Intersegment sales | Aerospace Systems [Member]
Revenue, Major Customer [Line Items]
Sales									$ 197	$ 295	$ 240
Concentration Risk, Percentage									2.00%	2.00%	2.00%
Intersegment sales | Innovation Systems
Revenue, Major Customer [Line Items]
Sales									$ 127	$ 0	$ 0
Concentration Risk, Percentage									4.00%	0.00%	0.00%
Intersegment sales | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales									$ 1,145	$ 954	$ 875
Concentration Risk, Percentage									10.00%	8.00%	8.00%
Intersegment sales | Technology Services [Member]
Revenue, Major Customer [Line Items]
Sales									$ 814	$ 1,035	$ 958
Concentration Risk, Percentage									19.00%	22.00%	20.00%
Operating Segments [Member] | Aerospace Systems [Member]
Revenue, Major Customer [Line Items]
Sales									$ 13,096	$ 12,131	$ 10,853
Concentration Risk, Percentage									100.00%	100.00%	100.00%
Operating Segments [Member] | Innovation Systems
Revenue, Major Customer [Line Items]
Sales									$ 3,276	$ 0	$ 0
Concentration Risk, Percentage									100.00%	0.00%	0.00%
Operating Segments [Member] | Mission Systems [Member]
Revenue, Major Customer [Line Items]
Sales									$ 11,709	$ 11,470	$ 11,161
Concentration Risk, Percentage									100.00%	100.00%	100.00%
Operating Segments [Member] | Technology Services [Member]
Revenue, Major Customer [Line Items]
Sales									$ 4,297	$ 4,687	$ 4,765
Concentration Risk, Percentage									100.00%	100.00%	100.00%