Segment Information (Details 1) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Number of reportable segments									3
Total sales	$ 6,634	$ 6,527	$ 6,375	$ 6,267	$ 6,397	$ 6,155	$ 6,000	$ 5,956	$ 25,803	$ 24,508	$ 23,526
Operating income	$ 767	$ 845	$ 855	$ 832	$ 831	$ 826	$ 797	$ 739	3,299	3,193	3,076
Operating Segments
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Operating income									2,959	2,935	2,920
Operating Segments | Aerospace Systems
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Total sales									11,955	10,828	9,940
Operating income									1,259	1,236	1,205
Operating Segments | MIssion Systems
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Total sales									11,382	10,928	10,674
Operating income									1,453	1,445	1,410
Operating Segments | Technology Services
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Total sales									4,750	4,825	4,819
Operating income									524	512	514
Intersegment Eliminations [Member]
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Total sales									2,284	2,073	1,907
Operating income									277	258	209
Intersegment Eliminations [Member] | Aerospace Systems
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Total sales									295	239	221
Operating income									33	28	27
Intersegment Eliminations [Member] | MIssion Systems
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Total sales									954	875	781
Operating income									141	136	97
Intersegment Eliminations [Member] | Technology Services
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Total sales									1,035	959	905
Operating income									103	94	85
Net FAS/CAS pension adjustment Income (Expense) [Member]
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Operating income									594	316	348
Corporate, Non-Segment [Member]
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Operating income									(250)	(53)	(190)
Segment Reconciling Items [Member]
Sales and Service Revenues by Segment (Table Amounts) [Abstract]
Operating income									$ (4)	$ (5)	$ (2)