Segment Information (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Additional information by Segment (Table Amounts) [Abstract]
Capital Expenditures	$ 928	$ 920	$ 471
Depreciation and Amortization	475	456	467
Aerospace Systems
Additional information by Segment (Table Amounts) [Abstract]
Capital Expenditures	665	451	237
Depreciation and Amortization	234	216	215
Mission Systems
Additional information by Segment (Table Amounts) [Abstract]
Capital Expenditures	164	372	141
Depreciation and Amortization	131	140	153
Technology Services
Additional information by Segment (Table Amounts) [Abstract]
Capital Expenditures	15	6	3
Depreciation and Amortization	40	37	36
Corporate
Additional information by Segment (Table Amounts) [Abstract]
Capital Expenditures	84	91	90
Depreciation and Amortization	$ 70	$ 63	$ 63