XML 101 R83.htm IDEA: XBRL DOCUMENT
v3.20.4

Pension and Other Postretirement Benefits - Schedule of Weighted Average Assumptions Used to Determine Benefit Obligations (Details) | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract] |  |  |  |
Discount rate |  | 2.40% | 3.00% |
Cash balance plan interest crediting rate |  | 3.00% | 3.00% |
Average duration for plans' projected cash flows |  | 12 years |  |
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] |  |  |  |
Discount rate to calculate service cost |  | 3.30% | 4.30% | 3.60%
Discount rate to calculate interest cost |  | 2.70% | 3.90% | 3.30%
Expected long-term rate of return on plan assets |  | 6.00% | 5.60% | 5.90%
Rate of compensation increase |  | 0.00% | 3.50% | 3.50%
Cash balance plan interest crediting rate |  | 0.0300 | 0.0300 | 0.0300
Period expected long-term rate of return is applied |  | 5 years |  |
Number of years over actual annual healthcare cost trend experience |  | 20 years |  |
Basis point of decrease identified In long term rate of return |  | 0.75% |  |
Scenario, forecast | United States |  |  |  |
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] |  |  |  |
Expected long-term rate of return on plan assets | 7.00% |  |  |

X
- Definition Average period of historical returns used to calculate expected future returns, years. + References No definition available. + Details
Name: | arnc_AveragePeriodOfHistoricalReturnsUsedToCalculateExpectedFutureReturns
Namespace Prefix: | arnc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Basis point of decrease identified in long term rate of return. + References No definition available. + Details
Name: | arnc_BasisPointOfDecreaseIdentifiedInLongTermRateOfReturn
Namespace Prefix: | arnc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Cash Balance Plan Interest Crediting Rate + References No definition available. + Details
Name: | arnc_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostCashBalancePlanInterestCreditingRate
Namespace Prefix: | arnc_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Interest Cost, Discount Rate + References No definition available. + Details
Name: | arnc_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostInterestCostDiscountRate
Namespace Prefix: | arnc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Service Cost, Discount Rate + References No definition available. + Details
Name: | arnc_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostServiceCostDiscountRate
Namespace Prefix: | arnc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Average duration refined yield curve model parallels the plans. + References No definition available. + Details
Name: | arnc_DefinedBenefitPlanFairValueAssumptionsAverageDurationRefinedYieldCurveModelParallelsPlans
Namespace Prefix: | arnc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition No of year over actual annual health care cost trend experience. + References No definition available. + Details
Name: | arnc_NoOfYearOverActualAnnualHealthcareCostTrendExperience
Namespace Prefix: | arnc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(1) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average rate of return on plan assets, used to determine net periodic benefit cost (credit) of defined benefit plan, in subsequent interim measurement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2919-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostChangeDueToSubsequentInterimMeasurementWeightedAverageExpectedLongTermRateOfReturnOnPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(3) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2919-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average rate of compensation increase used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(2) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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

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

X
- Details
Name: | srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanSponsorLocationAxis=country_US
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |