Goodwill (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2017	Dec. 31, 2016
Goodwill
Accumulated goodwill impairment losses	$ 2,877	$ 2,877
Goodwill, adjustments	(17)
Ingalls
Goodwill
Accumulated goodwill impairment losses	1,568	1,568
Newport News
Goodwill
Accumulated goodwill impairment losses	1,187	1,187
Technical Solutions
Goodwill
Accumulated goodwill impairment losses	122	$ 122
Goodwill, adjustments	$ (17)

Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a,h)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=84229725&loc=d3e961-128460

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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