Segment Information (Details 5) - 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
Segment Reporting Information [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
Intersegment sales and operating income (Table Amounts) [Abstract]
Operating income	$ 943	$ 1,172	$ 817	$ 848	$ 672	$ 829	$ 864	$ 853	3,780	3,218	3,277
Intersegment sales
Segment Reporting Information [Line Items]
Sales									2,283	2,284	2,073
Intersegment sales and operating income (Table Amounts) [Abstract]
Operating income									270	277	258
Intersegment sales | Aerospace Systems
Segment Reporting Information [Line Items]
Sales									197	295	240
Intersegment sales and operating income (Table Amounts) [Abstract]
Operating income									23	33	28
Intersegment sales | Innovation Systems
Segment Reporting Information [Line Items]
Sales									127	0	0
Intersegment sales and operating income (Table Amounts) [Abstract]
Operating income									1	0	0
Intersegment sales | Mission Systems
Segment Reporting Information [Line Items]
Sales									1,145	954	875
Intersegment sales and operating income (Table Amounts) [Abstract]
Operating income									165	141	136
Intersegment sales | Technology Services
Segment Reporting Information [Line Items]
Sales									814	1,035	958
Intersegment sales and operating income (Table Amounts) [Abstract]
Operating income									$ 81	$ 103	$ 94