XML 99 R66.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Goodwill and Other Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2017 USD ($) | Dec. 31, 2017 USD ($) segment | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($)
Goodwill [Roll Forward] |  |  |  |
Goodwill gross, beginning balance |  | $ 5,201 | $ 5,302 |
Accumulated impairment losses, beginning balance |  | (53) | (53) |
Goodwill, beginning balance |  | 5,148 | 5,249 |
Acquisitions and Divestitures |  |  | 47 |
Impairment |  | (719) | 0 | $ (25)
Translation and other |  | 106 | (148) |
Goodwill gross, ending balance | $ 5,307 | 5,307 | 5,201 | 5,302
Accumulated impairment losses, ending balance | (772) | (772) | (53) | (53)
Goodwill, ending balance | 4,535 | $ 5,148 | 5,249 | 5,249
Number of reportable segments | segment |  | 3 |  |
Engineered Products and Solutions |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Impairment | (719) | $ (719) |  |
Segment reporting, goodwill | 256 |  |  |
Global Rolled Products |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Segment reporting, goodwill | 59 |  |  |
Transportation and Construction Solutions |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Impairment |  |  |  | (25)
Segment reporting, goodwill | 18 |  |  |
Operating Segments | Engineered Products and Solutions |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Goodwill gross, beginning balance |  | 4,579 | 4,660 |
Accumulated impairment losses, beginning balance |  | 0 | 0 |
Goodwill, beginning balance |  | 4,579 | 4,660 |
Acquisitions and Divestitures |  |  | 47 |
Impairment |  | (719) |  |
Translation and other |  | 89 | (128) |
Goodwill gross, ending balance | 4,668 | 4,668 | 4,579 | 4,660
Accumulated impairment losses, ending balance | (719) | (719) | 0 | 0
Goodwill, ending balance | 3,949 | 4,579 | 4,660 | 4,660
Operating Segments | Global Rolled Products |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Goodwill gross, beginning balance |  | 181 | 201 |
Accumulated impairment losses, beginning balance |  | 0 | 0 |
Goodwill, beginning balance |  | 181 | 201 |
Acquisitions and Divestitures |  |  | 0 |
Impairment |  | 0 |  |
Translation and other |  | 12 | (20) |
Goodwill gross, ending balance | 193 | 193 | 181 | 201
Accumulated impairment losses, ending balance | 0 | 0 | 0 | 0
Goodwill, ending balance | 193 | 181 | 201 | 201
Operating Segments | Transportation and Construction Solutions |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Goodwill gross, beginning balance |  | 110 | 111 |
Accumulated impairment losses, beginning balance |  | (53) | (53) |
Goodwill, beginning balance |  | 57 | 58 |
Acquisitions and Divestitures |  |  | 0 |
Impairment |  | 0 |  |
Translation and other |  | 3 | (1) |
Goodwill gross, ending balance | 113 | 113 | 110 | 111
Accumulated impairment losses, ending balance | (53) | (53) | (53) | (53)
Goodwill, ending balance | 60 | 57 | 58 | 58
Corporate |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Goodwill gross, beginning balance |  | 331 | 330 |
Accumulated impairment losses, beginning balance |  | 0 | 0 |
Goodwill, beginning balance |  | 331 | 330 |
Acquisitions and Divestitures |  |  | 0 |
Impairment |  | 0 |  |
Translation and other |  | 2 | 1 |
Goodwill gross, ending balance | 333 | 333 | 331 | 330
Accumulated impairment losses, ending balance | 0 | 0 | 0 | 0
Goodwill, ending balance | $ 333 | $ 331 | $ 330 | $ 330

X
- Definition Goodwill acquisition and divestitures. + References No definition available. + Details
Name: | arnc_GoodwillAcquisitionAndDivestitures
Namespace Prefix: | arnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Segment reporting reconciling items goodwill assets. + References No definition available. + Details
Name: | arnc_SegmentReportingReconcilingItemsGoodwillAssets
Namespace Prefix: | arnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount after accumulated impairment loss of an asset representing 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 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975 + Details
Name: | us-gaap_Goodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits 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 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 + Details
Name: | us-gaap_GoodwillForeignCurrencyTranslationGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount before accumulated impairment loss of an asset representing 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 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a,h) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 + Details
Name: | us-gaap_GoodwillGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition 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. + References 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 + Details
Name: | us-gaap_GoodwillImpairedAccumulatedImpairmentLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of loss from the write-down 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 350 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13854-109267 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13777-109266 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 + Details
Name: | us-gaap_GoodwillImpairmentLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_GoodwillRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_NumberOfReportableSegments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=arnc_EngineeredProductsAndSolutionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=arnc_GlobalRolledProductsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=arnc_TransportationAndConstructionSolutionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConsolidationItemsAxis=us-gaap_CorporateNonSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |