v3.22.0.1

Restructuring and Other Charges - Restructuring and Other Charges by Segment (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Restructuring Cost and Reserve [Line Items] |  |  |
Restructuring and other charges | $ 624 | $ 188 | $ 87
Segment total |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Restructuring and other charges | 6 | (24) | 81
Corporate |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Restructuring and other charges | 618 | 212 | 6
Rolled Products | Segment total |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Restructuring and other charges | 1 | (15) | 47
Building and Construction Systems | Segment total |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Restructuring and other charges | (2) | 5 | 33
Extrusions | Segment total |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Restructuring and other charges | $ 7 | $ (14) | $ 1

X
- Definition Restructuring, Settlement And Impairment Provisions, Including Gain (Loss) On Disposition Of Assets And Business + References No definition available. + Details
Name: | arnc_RestructuringSettlementAndImpairmentProvisionsIncludingGainLossOnDispositionOfAssetsAndBusiness
Namespace Prefix: | arnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

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

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

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

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

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