XML 72 R55.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Summary of Significant Accounting Policies - Additional Information (Details) |  |  | 1 Months Ended | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Dec. 31, 2017 USD ($) reporting_unit | Mar. 30, 2012 USD ($) | Jan. 31, 2018 reporting_unit | Dec. 31, 2018 USD ($) | Mar. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2018 USD ($) reporting_unit | Dec. 31, 2017 USD ($) reporting_unit | Dec. 31, 2016 USD ($) reporting_unit | Jan. 01, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Original maturity of cash equivalents |  |  |  |  |  |  | 3 months |  |  |
Number of reporting units | reporting_unit | 4 |  | 3 |  |  |  | 6 |  | 8 |
Segment allocation, goodwill recognized | $ 4,535,000,000 |  |  | $ 4,500,000,000 |  | $ 4,535,000,000 | $ 4,500,000,000 | $ 4,535,000,000 | $ 5,148,000,000 |
Minimum percentage of estimated fair value of reporting unit to be less than carrying amount of goodwill |  |  |  |  |  |  | 50.00% |  |  |
Period required for impairment testing of reporting units |  |  |  |  |  |  | 3 years |  |  |
Impairment of goodwill (A and O) |  |  |  |  | $ 0 |  | $ 0 | 719,000,000 | 0 |
Revenue, terms of payment, period |  |  |  |  |  |  | 30 days |  |  |
Businesses expected to be disposed within, years |  |  |  |  |  |  | 1 year |  |  |
Cash received for receivables |  | $ 50,000,000 |  |  |  |  | $ 1,016,000,000 | 792,000,000 | 778,000,000 |
Payment for debt extinguishment or debt prepayment cost |  |  |  |  |  |  | 17,000,000 | 52,000,000 | 3,000,000 |
Restricted cash | 4,000,000 |  |  | 6,000,000 |  | 4,000,000 | 6,000,000 | 4,000,000 | 15,000,000 |
Net periodic benefit cost, non-service |  |  |  |  |  |  | $ 112,000,000 | 154,000,000 | $ 135,000,000 |
Amount of stranded tax effects in accumulated other comprehensive income reclassified to accumulated deficit |  |  |  | 367,000,000 |  |  |  |  |  |
Engineered Products and Solutions |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Number of reporting units | reporting_unit |  |  |  |  |  |  |  |  | 4 |
Number of reporting units for goodwill allocation | reporting_unit |  |  |  |  |  |  | 3 |  |  |
Segment allocation, goodwill recognized | 4,205,000,000 |  |  | 4,179,000,000 |  | 4,205,000,000 | $ 4,179,000,000 | 4,205,000,000 |  |
Impairment of goodwill (A and O) |  |  |  |  |  | 719,000,000 |  | 719,000,000 |  |
Engineered Products and Solutions | Alcoa Forging and Extrusions |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Impairment of goodwill (A and O) |  |  |  | 719,000,000 |  |  |  |  |  |
Transportation and Construction Solutions |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Number of reporting units | reporting_unit |  |  |  |  |  |  |  |  | 3 |
Segment allocation, goodwill recognized | 78,000,000 |  |  | 76,000,000 |  | 78,000,000 | 76,000,000 | 78,000,000 |  |
Impairment of goodwill (A and O) |  |  |  |  |  |  |  | $ 0 |  |
Global Rolled Products |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Number of reporting units | reporting_unit |  |  |  |  |  |  |  | 1 | 1 |
Segment allocation, goodwill recognized | $ 252,000,000 |  |  | 245,000,000 |  | $ 252,000,000 | $ 245,000,000 | $ 252,000,000 |  |
Impairment of goodwill (A and O) |  |  |  |  |  |  |  | $ 0 |  |
Minimum | Engineered Products and Solutions |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Percentage of total goodwill allocated to two reporting units |  |  |  |  |  |  | 90.00% |  |  |
Arconic Engines |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Segment allocation, goodwill recognized |  |  |  | 2,065,000,000 |  |  | $ 2,065,000,000 |  |  |
Arconic Fastening Systems |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Segment allocation, goodwill recognized |  |  |  | 1,607,000,000 |  |  | 1,607,000,000 |  |  |
Arconic Engineered Structures |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Segment allocation, goodwill recognized |  |  |  | $ 507,000,000 |  |  | $ 507,000,000 |  |  |
Disks Asset Group |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Impairment of goodwill (A and O) |  |  |  |  | $ 0 |  |  |  |  |
Subsequent Event | Minimum |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Right-of-use asset and operating lease liability |  |  |  |  |  |  |  |  |  | $ 300,000,000
Subsequent Event | Maximum |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |  |
Right-of-use asset and operating lease liability |  |  |  |  |  |  |  |  |  | $ 340,000,000

X
- Definition Cash equivalents maximum maturity period of highly liquid investments. + References No definition available. + Details
Name: | arnc_CashEquivalentsMaximumMaturityPeriodOfHighlyLiquidInvestments
Namespace Prefix: | arnc_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Discontinued operations businesses expected to be disposed within certain years. + References No definition available. + Details
Name: | arnc_DiscontinuedOperationsBusinessesExpectedToBeDisposedWithinCertainYears
Namespace Prefix: | arnc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum percentage of estimated fair value of reporting unit to be less than carrying amount of goodwill. + References No definition available. + Details
Name: | arnc_MinimumPercentageOfEstimatedFairValueOfReportingUnitToBeLessThanCarryingAmountOfGoodwill
Namespace Prefix: | arnc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Net Periodic Benefit Cost, Non-service + References No definition available. + Details
Name: | arnc_NetPeriodicBenefitCostNonservice
Namespace Prefix: | arnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of reporting units for goodwill allocation. + References No definition available. + Details
Name: | arnc_NumberOfReportingUnitsForGoodwillAllocation
Namespace Prefix: | arnc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of total goodwill allocated to reporting units. + References No definition available. + Details
Name: | arnc_PercentageOfGoodwillAllocatedToReportingUnits
Namespace Prefix: | arnc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period Required For One Quantitative Impairment Test To Be Performed For Each Reporting Unit + References No definition available. + Details
Name: | arnc_PeriodRequiredForOneQuantitativeImpairmentTestToBePerformedForEachReportingUnit
Namespace Prefix: | arnc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Revenue, Terms Of Payment, Period + References No definition available. + Details
Name: | arnc_RevenueTermsOfPaymentPeriod
Namespace Prefix: | arnc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Summary Of Significant Accounting Policies [Line Items] + References No definition available. + Details
Name: | arnc_SummaryOfSignificantAccountingPoliciesLineItems
Namespace Prefix: | arnc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Income Tax Expense (Benefit) + References No definition available. + Details
Name: | arnc_TaxCutsAndJobsActOf2017IncompleteAccountingTransitionTaxForAccumulatedForeignEarningsProvisionalIncomeTaxExpense
Namespace Prefix: | arnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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://fasb.org/us-gaap/role/ref/legacyRef -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 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266 + Details
Name: | us-gaap_Goodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13854-109267 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13777-109266 + Details
Name: | us-gaap_GoodwillImpairmentLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment. + References No definition available. + Details
Name: | us-gaap_NumberOfReportingUnits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsOfDebtExtinguishmentCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow associated with the sale of receivables arising from the financing of goods and services. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfFinanceReceivables
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cash restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=98513485&loc=SL98516268-108586 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(1)(a)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(2)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_RestrictedCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Details
Name: | srt_ProductOrServiceAxis=arnc_AlcoaForgingAndExtrusionsMember
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_StatementBusinessSegmentsAxis=arnc_GlobalRolledProductsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ReportingUnitAxis=arnc_ArconicEnginesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ReportingUnitAxis=arnc_ArconicFasteningSystemsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ReportingUnitAxis=arnc_ArconicEngineeredStructuresMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ReportingUnitAxis=arnc_DisksBusinessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |