Segment Information (Unaudited) (Details 1) $ in Millions	3 Months Ended
Mar. 31, 2018 USD ($) segment	Mar. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| segment	3
Sales	$ 6,735	$ 6,410
Operating income	854	862
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating income	762	741
Operating Segments [Member] \| Aerospace Systems [Member]
Segment Reporting Information [Line Items]
Sales	3,280	2,984
Operating income	341	323
Operating Segments [Member] \| Mission Systems [Member]
Segment Reporting Information [Line Items]
Sales	2,883	2,800
Operating income	371	359
Operating Segments [Member] \| Technology Services [Member]
Segment Reporting Information [Line Items]
Sales	1,144	1,190
Operating income	122	129
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Sales	572	564
Operating income	72	70
Net FAS (service)/CAS pension adjustment [Member]
Segment Reporting Information [Line Items]
Operating income	127	154
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating income	(34)	(32)
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Operating income	$ (1)	$ (1)

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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The net result for the period of deducting operating expenses from operating revenues.

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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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