<DefinitionAndReference>
  <Element Id="dei_EntityFilerCategory">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredIncomeTaxesAndTaxCredits">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NotionalAmountOfForeignCurrencyDerivativePurchaseContracts">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedAccrualCarryingValuePaymentsFundedByCompany">
    <definition>The payments made in the period by the company which reduced asbestos-related reserves.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfGuaranteeObligationsTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PowerPlantDisputeCostsIncurred">
    <definition>The charge against earnings incurred in the power plant dispute in Ireland.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_OtherDeductionsNet">
    <definition>Other Deductions includes both (1) Other General Expense, and (2) Other Nonoperating Expense.
(1) Other General Expense: Amount of general expenses not normally included in Selling, general and administrative expenses.
(2) Other Nonoperating Expense: Any other expense items resulting from secondary business-related activities, excluding those considered part of the normal operations of the business that have not been previously categorized.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ComprehensiveIncomeNoteTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DebtInstrumentFeeMinimum">
    <definition>Description of a minimum fee associated with the debt instrument, including a commitment fee on unborrowed portions of a lender's total contractual commitment.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DepreciationDepletionAndAmortization">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ContractProfitChanges">
    <definition>The current period impact on final estimated contract profit resulting from a change in estimated final contract revenues or costs relating to the revaluation of work performed on contracts in prior periods.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_WriteOffOfDeferredDebtIssuanceCost">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanServiceCost">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_NetCashInflowsOutflowsOnSettlementOfDerivativeInstrumentsNotDesignatedAsHedgingInstruments">
    <definition>Amount of net cash inflows/(outflows) in the period from the settlement of derivatives included within the "net change in contracts in process and billings in excess of costs and estimated earnings on uncompleted contracts" in the consolidated statement of cash flows.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_GuaranteesAndWarrantiesTextBlock">
    <definition>Environmental-Disclosure of material liabilities for remediation, site restoration, postclosure, monitoring commitments, or other exit costs that may occur on the sale, disposal or abandonment of a property as a result of unanticipated contamination of the assets.Amount accrued as of the balance sheet date for environmental costs associated with the sale, disposal or abandonment of property.Product - Disclosure for standard and extended product warranties and other product guarantee contracts, including a tabular reconciliation of the changes in the guarantor's aggregate product warranty liability for the reporting period.Letters of credits and surety bonds - Provides pertinent information about each guarantee obligation, or each group of similar guarantee obligations, including (a) the nature of the guarantee, including its term, how it arose, and the events or circumstances that would require the guarantor to perform under the guarantee; (b) the maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee; (c) the current carrying amount of the liability, if any, for the guarantor's obligations under the guarantee; and (d) the nature of any recourse provisions under the guarantee, and any assets held either as collateral or by third parties, and any relevant related party disclosure.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_TotalMaturities">
    <definition>Total current and long-term carrying values as of the balance sheet date of debt.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StandardProductWarrantyAccrual">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_MeasurementMethodProgressTowardsCompletionContractsGreaterThan5000">
    <definition>For contracts with a value of $5,000 or greater, progress towards completion is measured based on physical completion of individual tasks for all contracts.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PatentsAndTrademarksUsefulLife">
    <definition>The range of useful lives of all patents and trademarks.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfDebtInstrumentsTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CashAndCashEquivalentsAtCarryingValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_GainLossRelatedToSettlementWithAsbestosInsurers">
    <definition>The amount of increase of the asbestos-related insurance asset and corresponding gain as a result of settlements with insurers.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_VariableInterestEntitiesCarryingAmountOfCurrentAssetsConsolidatedVies">
    <definition>The aggregate carrying amount of all variable interest entities' current assets consolidated into the statement of financial position. In general, a VIE is a corporation, partnership, trust, or any other legal structure used for business purposes that either (a) does not have equity investors with voting rights or (b) has equity investors that do not provide sufficient financial resources for the entity to support its activities.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PropertyPlantAndEquipmentNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DebtDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardRestrictedSharesNonvestedNumber">
    <definition>The number of outstanding restricted shares on nonstock option plans (for example, phantom stock plan, stock appreciation rights plan, revenue or profit achievement stock award plan) for which the employer has issued equity instruments with restrictions that will be removed upon vesting.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SegmentReportingInformationRevenueFromExternalCustomers">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentDividendsOrDistributions">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LineOfCreditFacilityDescription">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EarningsPerSharePolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_CashFlowHedgeGainLossReclassifiedToInterestExpenseNetTextblock">
    <definition>A table or schedule that identifies and provides pertinent information about cash flow hedge gain/(loss) reclassified to interest expense.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ImpactOnContractExceed1000">
    <definition>Impact On Contract Exceed 1000</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedReservesSensitivityImpactOnLiabilityMaximum">
    <definition>Additional expense that would be recognized in the statement of operations for a 25% increase in the average asbestos-related claim indemnity settlement amount based on the increase in the asbestos-related liability balance and assuming no change in the assumptions currently used to estimate the asbestos-related insurance asset.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RepaymentOfLongTermDebtAndCapitalLeaseObligations">
    <definition>The cash outflow for debt initially having maturity and obligation for lease meeting the criteria for capitalization due after one year or beyond the normal operating cycle, if longer.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_LetterOfCreditHeldByClient">
    <definition>Amount of letter of credit held by client that is under dispute.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ClaimsYetToBeExpended">
    <definition>The amount of assumed recovery of commercial claims which has not been spent year-to-date.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DebtServiceLetterOfCreditRelatedPartyDisclosureAmountDrawn">
    <definition>The amount that has been drawn on the debt service letter of credit to cover debt payments of equity investee.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncomeTaxExpenseBenefit">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GoodwillAndIntangibleAssetsPolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IssuanceOfRegisteredCommonSharesUponConversionOfPreferredSharesAndCancellationOfCommonShares">
    <definition>Value of stock that was converted from one type or class to another during the period. Conversion may be among classes of common or nonredeemable preferred stock or from common stock or nonredeemable preferred stock to nonredeemable preferred stock or common stock, respectively.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_NetChangeInContractsInProcessAndBillingsInExcessOfCostsAndEstimatedEarningsOnUncompletedContracts">
    <definition>The net change during the reporting period in the Billing in Excess of Cost of Earnings (reflecting cash payments received before the related costs have been incurred) net of the net change in the Contracts in Process (amount of revenue for work performed for which the billing milestone has not occurred, net of uncollectible accounts).</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredTaxAssetsNetNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedCostsAverageCostPerResolvedClaim">
    <definition>The average historic combined indemnity and defense cost per resolved asbestos-related claim.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ProceedsFromSharePurchaseWarrantExercised">
    <definition>The cash inflow associated with the amount received from holders exercising their warrants.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LineOfCreditFacilityInterestRateDescription">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeAmortizationOfDefinedBenefitPlanNetPriorServiceCostCreditRecognizedInNetPeriodicBenefitCostBeforeTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ExpirationOfStatuteOfLimitationsAfterBalanceSheetDate">
    <definition>Expiration Of Statute Of Limitations After Balance Sheet Date</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_FairValueOfFinancialInstrumentsPolicyTextBlock">
    <definition>Describes an entity's accounting policy for determining the fair value of its financial instruments.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredFinanceCostsGross">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedLiabilityBalanceSheetCaption">
    <definition>The balance of the asbestos-related liability in the balance sheet  pertaining to the asbestos-related accrual.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_UnrecognizedTaxBenefitsReversalOfInterestOnIncomeTaxesExpense">
    <definition>This element represents the reversal of interest expense previously accrued on uncertain tax positions, which were ultimately not assessed.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InvestmentIncomeInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedInsuranceRecoveryReceivableCurrent">
    <definition>Estimate of recoveries anticipated to be collected within one year from insurers relating to asbestos claims.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesOther">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_RelatedPartyTransactionRevenuesFromTransactionsWithRelatedParty">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedAccrualAtCarryingValueBeginningBalance">
    <definition>The carrying amount as of the balance sheet date of the combined total of asbestos-related reserves.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LiabilitiesCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_DocumentPeriodEndDate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityCentralIndexKey">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ProceedsFromStockOptionsExercised">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedClaimsSettledAndDismissedNumber">
    <definition>The number of asbestos-related claims settled and dismissed during the period.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DebtInstrumentMaturityDate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RegisteredSharesToBeAcquiredRemainingRepurchaseAuthorization">
    <definition>Remaining U.S. dollar value of outstanding shares that may be purchased under publicly announced share repurchase program approved by the Board of Directors.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DueFromRelatedPartiesCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_SeparateProjectsWithContractRevisions">
    <definition>Number of separate projects that had final estimated contract profit revisions whose impact on contract profit exceeded a million.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanInterestCost">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ReturnOfInvestmentFromUnconsolidatedAffiliates">
    <definition>The cash inflow for a return of capital from a noncontrolled interest.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ConsolidationPolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DebtInstrumentPrincipalOutstanding">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedInsuranceRecoveryReceivable">
    <definition>Estimate of recoveries anticipated to be collected in more than one year from insurers relating to asbestos claims.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StockholdersEquity">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LineOfCreditFacilityBorrowingCapacityDescription">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedIndemnityCostsPayments">
    <definition>The total cumulative asbestos-related indemnity costs paid through the balance sheet date.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedPendingClaimsNumberBeginningBalance">
    <definition>The total number of open claims as of the balance sheet date.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_RestrictedCashAndCashEquivalentsNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccountsPayableCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ReceivablesLongTermContractsOrPrograms">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IncomeBeforeIncomeTaxesTotal">
    <definition>Sum of operating profit and nonoperating income (expense) before income taxes and including the portion attributable to noncontrolling interest.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ShareBasedCompensationOptionAndIncentivePlansPolicyTextBlock">
    <definition>Disclosure of share-based compensation policies.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IssuanceOfCommonSharesUponExerciseOfSharePurchaseWarrants">
    <definition>Value of common stock issued during the period upon the conversion of convertible securities</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NetIncomeLoss">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_Assets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfVariableInterestEntitiesTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GuaranteeObligationsMaximumExposure">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedDefenseCostsPayments">
    <definition>The total cumulative asbestos-related defense costs paid through the balance sheet date.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedAccrualCarryingValueProvision">
    <definition>The charge against earnings in the period to increase asbestos-related reserves, net of any adjustments to increase asbestos-related assets or to reduce previously estimated charges.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedTotalClaimsFiledNumber">
    <definition>The total number of asbestos-related claims filed against the company.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_UnrecognizedTaxBenefitsReversalOfIncomeTaxPenaltiesExpense">
    <definition>This element represents the reversal of income tax penalties on uncertain tax positions, which were ultimately not assessed.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_CustomerRelationshipsPipelineAndBacklogUsefulLife">
    <definition>The range of useful lives of all customer relationahsips, pipeline and backlog. This may be stated as a fixed number (for example, 10 years) if all assets have the same useful life, or it can be stated in a range (for example, six to eight years) if there is a range of useful lives in the asset group.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccruedIncomeTaxesCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_CurrentFiscalYearEndDate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_BusinessCombinationDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LiabilitiesAndStockholdersEquity">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ProceedsFromIssuanceOfLongTermDebt">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAmortizationOfTransitionObligationsAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_DocumentFiscalPeriodFocus">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AmountOfDeferredCostsRelatedToLongTermContracts">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SegmentReportingDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GrossProfit">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncreaseDecreaseInReceivables">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PaymentsOfDividendsMinorityInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ContractRevenueCost">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_TemporaryEquityCarryingAmount">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SellingGeneralAndAdministrativeExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DescriptionOfLocationOfGainLossOnInterestRateCashFlowHedgeDerivativeInFinancialStatements">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PotentialCleanUpObligationLiability">
    <definition>Maximum potential clean-up obligation liability for off-site disposal or treatment sites where the company has received a notice of potential liability.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_NetCashOutflowsInflowsAsResultOfCurrentPeriodActivityRelatedToPaymentsForAsbestosRelatedIndemnity">
    <definition>The net cash outflows/(inflows) as a result of current period activity related to payments for asbestos-related indemnity</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_BillingsInExcessOfCost">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationMaximumCappedSalaryGrowth">
    <definition>Maximum capped salary growth.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeDescriptionOfHedgedItem">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherAssetsCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SignificantAccountingPoliciesTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_DocumentFiscalYearFocus">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommonStockValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeFairValueOfDerivativeAsset">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlansNetGainLossRecognizedInNetPeriodicBenefitCostBeforeTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IncreaseInRollingAsbestosLiabilityEstimate">
    <definition>Increase in rolling asbestos liability estimate</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_UseOfEstimatesPolicyTextBlock">
    <definition>Provides an entity's explanation that the preparation of financial statements in conformity with generally accepted accounting principles requires the use of management estimates. Estimates used in the determination of carrying amounts of assets or liabilities, or in disclosure of gain or loss contingencies should be disclosed if known information available prior to issuance of the financial statements indicates that both of these criteria are met: (1) It is at least reasonably possible that the estimate of the effect on the financial statements of a condition, situation, or set of circumstances that existed at the date of the financial statements will change in the near term (less than one year from the date of issuance) due to one or more future confirming events, and (2) The effect of the change would be material to the financial statements. The disclosure should indicate the nature of the uncertainty and include an indication that it is at least reasonably possible that a change in the estimate will occur in the near term. Disclosure of the factors that cause the estimate to be sensitive to change also is encouraged. Entities also may identify those areas that are subject to significant estimates.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedTotalLiabilityBalanceSheetCaption">
    <definition>The total estimated balance of the asbestos-related liabilities in the balance sheet.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_FutureAmortizationExpenseCurrentFiscalYear">
    <definition>The amount of amortization expense expected to be recognized during the current fiscal year.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedDefenseCostsAsProportionOfTotalCosts">
    <definition>The historical percentage of total asbestos defense and indemnity costs that relate to asbestos-related defense costs.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfGoodwillTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ConsolidationVariableInterestEntityPolicyTextBlock">
    <definition>Describes an entity's accounting policy regarding its principles of consolidation for variable interest entities.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_SegmentReportingOperatingIncomeLoss">
    <definition>Amount of income or loss for the reportable segment before depreciation and amortization, interest expense, income taxes, and extraordinary items.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfNewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShortTermInvestments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_EquityMethodInvestmentSummarizedFinancialInformationIncomeBeforeIncomeTaxes">
    <definition>This item represents the disclosure of summarized financial information for unconsolidated subsidiaries and 50 percent-or-less owned entities accounted for using the equity method of accounting. If investments in common stock of corporate joint ventures or other investments accounted for under the equity method are, in the aggregate, material in relation to the financial position or results of operations of an investor, it may be necessary to present summarized information as to assets of the investee, or group of investments for which combined disclosure is appropriate, either by individual financial statement caption or in groups, as appropriate. Such summarized financial information may, at a minimum, include income before income taxes.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentLiabilities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedAccrualAtCarryingValueRelatedToOutstandingClaims">
    <definition>The carrying amount as of the balance sheet date of the portion of the combined total of asbestos-related indemnity and defense costs related to open (outstanding) claims.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_OtherIncomeNet">
    <definition>Other Income includes both (1) Income (Loss) from Equity Method Investments and (2) Other Nonoperating Income.
(1) Income (Loss) from Equity Method Investments: This item represents the entity's proportionate share for the period of the undistributed net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. Such amount typically reflects adjustments similar to those made in preparing consolidated statements, including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between cost and underlying equity in net assets of the investee at the date of investment.
(2) Other Nonoperating Income:  The aggregate amount of other income amounts resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income recognized for the period. Such amounts may include miscellaneous other income items.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsInYearOne">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FutureAmortizationExpenseYearThree">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommonStockParOrStatedValuePerShare">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DefinedBenefitPlanDiscretionaryContributionsByEmployer">
    <definition>The amount of discretionary contributions made by the employer.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeNetGainLossBeforeTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CashAndCashEquivalentsPolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IssuaneOfCommonSharesUponVestingOfRestrictedAwards">
    <definition>Issuane of common shares upon vesting of restricted awards</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NetIncomeLossAttributableToNoncontrollingInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FutureAmortizationExpenseYearOne">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrProgramsExpectedToBeCollectedWithinOneYear">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_EstimatedAsbestosLiabilityRelatedToRolling15Year">
    <definition>Estimated asbestos liability related to the rolling 15-year</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InterestExpenseDebt">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GainLossOnSaleOfOtherAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeLiabilityDesignatedAsHedgingInstrumentFairValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ContractsReceivableClaimsAndUncertainAmounts">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncreaseDecreaseInRestrictedCash">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetSalesOrGrossRevenue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FutureAmortizationExpenseYearTwo">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedRecoveriesAndLiabilitiesTextBlock">
    <definition>The total estimated asbestos-related claim recoveries and asbsetos-related liabilities by balance sheet location.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DerivativeCurrencyBoughtOrSold">
    <definition>Identification of the specific currency to be purchased or sold upon settlement or exercise of the foreign currency derivative.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfDerivativeInstrumentsTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ProfitLoss">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PowerPlantDisputeExcessSoughtByClient">
    <definition>Amount client contends it is owed under the purchse order as a result of our alleged failures.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_GuaranteeForObligationRelatedParty">
    <definition>Describes certain required disclosures for those guarantees that are issued to benefit entities meeting the definition of a related party.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GuaranteeObligationsUnlimitedExposure">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_InstallationCostsForMercuryControlRequirementEquipment">
    <definition>The estimated costs to install equipment to meet mercury control requirements per New Jersey mercury air emission regulations.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PatentTrademarkAmortizationPeriodMaximum">
    <definition>Patent Trademark Amortization Period Maximum</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DebtInstrumentFeeMaximum">
    <definition>Description of a maximum fee associated with the debt instrument, including a commitment fee on unborrowed portions of a lender's total contractual commitment.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedPendingClaimsTextBlock">
    <definition>This element captures the activity for open asbestos-related claims for the period specified.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RetentionMoniesHeldByClient">
    <definition>Total amounts included within current and noncurrent receivables, billed or unbilled, under long-term contracts, which represent claims or other similar items subject to uncertainty concerning their determination or ultimate realization.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_OtherIntangibleAssetsAmortizationPeriodMaximum">
    <definition>Other Intangible Assets Amortization Period Maximum</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ProductWarrantyDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NotionalAmountOfInterestRateDerivatives">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredTaxLiabilitiesNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfRemainingSharesAvailableAsConditionalCapital">
    <definition>The number of remaining available conditional capital registered shares available at the balance sheet date.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EarningsPerShareDiluted">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_AmendmentFlag">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_TotalTemporaryEquity">
    <definition>TOTAL TEMPORARY EQUITY</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_Liabilities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_FiscalYearDescription">
    <definition>Fiscal Year Description</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DebtInstrumentInterestRateStatedPercentage">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StandardProductWarrantyAccrualPayments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccruedLiabilitiesCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ProceedsFromShortTermDebt">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommonStockSharesAuthorized">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_OperatingRevenuesByIndustryTextBlock">
    <definition>Operating revenues from third-parties disclosed by industry.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FiniteLivedIntangibleAssetsGross">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_BusinessAcquisitionNameOfAcquiredEntity">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AdditionalPaidInCapital">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncomeTaxPolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_VariableInterestEntitiesCarryingAmountOfCurrentLiabilitiesConsolidatedVies">
    <definition>The aggregate carrying amount of all the variable interest entities' current liabilities consolidated into the statement of financial position. In general, a VIE is a corporation, partnership, trust, or any other legal structure used for business purposes that either (a) does not have equity investors with voting rights or (b) has equity investors that do not provide sufficient financial resources for the entity to support its activities.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PaymentsForProceedsFromShortTermInvestments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NetCashProvidedByUsedInOperatingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NotionalAmountOfForeignCurrencyDerivativeSaleContracts">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfEarningsPerShareBasicAndDilutedTextBlock">
    <definition>Schedule Of Earnings Per Share Basic And Diluted [Text Block]</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlanNetTransitionAssetObligationRecognizedInNetPeriodicBenefitCostBeforeTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedNewClaimsFiledNumber">
    <definition>The total number of new claims filed during the period.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DebtInstrumentFairValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AveragePerClaimIndemnityIncreaseRate">
    <definition>The required increase in the entity's average per claim indemnity settlement amount for sensitivity analysis.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_UnsettledAsbestosInsuranceAsset">
    <definition>The estimate of the value of the unsettled asbestos insurance asset related to ongoing litigation in New York state court.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FutureAmortizationExpenseYearFour">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DisclosureOfShareBasedCompensationArrangementsByShareBasedPaymentAwardFairValueAssumptionsTextBlock">
    <definition>Disclosure of assumptions of a stock option or other award plan under which share-based compensation is awarded to employees used to determine the fair value of the shares granted, exercised, forfeited, and issued and outstanding pertaining to that plan.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanContributionsByEmployer">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_VariableInterestEntitiesCarryingAmountOfNetAssetsConsolidatedVies">
    <definition>The aggregate carrying amount of all the variable interest entities' net assets consolidated into the statement of financial position. In general, a VIE is a corporation, partnership, trust, or any other legal structure used for business purposes that either (a) does not have equity investors with voting rights or (b) has equity investors that do not provide sufficient financial resources for the entity to support its activities.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_NumberOfResidencesWithTceInWaterSupply">
    <definition>Number of residences whose domestic water wells contained trichloroethylene ("TCE").</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedAccruedExpensesCurrent">
    <definition>Estimated liability due within one year to settle asbestos claims.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DefenseCostsAndCashReceiptsFromInsuranceSettlementProceeds">
    <definition>Defense costs and cash receipts from insurance settlement proceeds</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PaymentsForRepurchaseOfCommonStock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AllocatedShareBasedCompensationExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncomeLossFromEquityMethodInvestments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StandardProductWarrantyAccrualPreexistingIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RevolvingBorrowingsOption">
    <definition>The amount of the letter of credit facility available, at the entity's option, for use as revolving borrowings.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_TemporaryEquityIncreaseInCarryingAmount">
    <definition>The amount of increase in temporary equity at the balance sheet date due to compensation cost recognized during the period for those equity awards with intrinsic value on the grant date.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensation">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RegisteredSharesToBeAcquiredInitialRepurchaseAuthorization">
    <definition>Initial U.S. dollar value of outstanding shares that may be purchased under publicly announced share repurchase program approved by the Board of Directors.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquityOrCapital">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_EmployeeServiceShareBasedCompensationUnrecognizedCompensationCostsOnNonvestedRestrictedAwards">
    <definition>As of the latest balance-sheet date presented, the total compensation cost related to outstanding, nonvested share-based compensation restricted awards not yet recognized (will be charged against earnings as services are performed or other vesting criteria are met).</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeFairValueOfDerivativeLiability">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_DocumentType">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RevenueRecognitionPercentageOfCompletionMethodTextBlock">
    <definition>Describes an entity's accounting policy for revenue recognition for long-term construction-type contracts accounted for using the percentage-of-completion method. This should include the method or methods of measuring extent of progress toward completion. If the entity departs from using the percentage-of-completion method for a single contract or a group of contracts for which reasonably dependable estimates cannot be made, such a departure from the basic policy should be disclosed.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedInsuranceRecoveryReceivableNonCurrent">
    <definition>Estimate of recoveries anticipated to be collected in more than one year from insurers relating to asbestos claims.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsByMajorClassTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherLiabilitiesNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AssetsCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PatentTrademarkAmortizationPeriodMinimum">
    <definition>Patent Trademark Amortization Period Minimum</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RetirementOfRegisteredSharesUnderRegisteredShareRepurchaseProgramTextBlock">
    <definition>This element may be used to describe the share repurchase program authorized by an entity's Board of Directors and treatment of shares upon purchase under the program.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RegisteredSharesConditionallyAuthorized">
    <definition>The maximum number of common shares conditionally permitted to be issued by an entity's charter and bylaws.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedTotalRelatedReceivable">
    <definition>The total estimated recoveries anticipated to be collected from insurers relating to asbestos claims in the balance sheet.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_MeasurementMethodProgressTowardsCompletionContractsLessThan5000">
    <definition>For contracts with a value of less than $5,000, progress towards completion is measured based on the ratio of costs incurred to total estimated contract costs.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_LetterOfCreditFacilityAmountOutstanding">
    <definition>Amount secured by letters of credit under the U.S. senior credit facility as of the balance-sheet date.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncomeTaxDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ComprehensiveIncomeForParentAndNonControllingInterests">
    <definition>Comprehensive Income For Parent And Non-Controlling Interests</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IncrementalCommonSharesAttributableToParticipatingNonVestedRestrictedAwards">
    <definition>This element represents the non-vested portion of restricted awards issued.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommitmentsAndContingencies2009">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InvestmentsInAndAdvancesToAffiliatesScheduleOfInvestmentsTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_Contractualpaymentrelatedtoprioracquisition">
    <definition>ContractualPaymentRelatedToPriorAcquisition</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IntangibleAssetsNetExcludingGoodwill">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_TemporaryEquityDecreaseInCarryingAmount">
    <definition>The amount of decrease in temporary equity at the balance sheet date due to the intrinsic value of equity awards vested during the period for those equity awards with intrinsic value on the grant date.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_VariableInterestEntitiesCarryingAmountOfOtherLiabilitiesConsolidatedVies">
    <definition>The aggregate carrying amount of all the variable interest entities' liabilities, other than current liabilities, consolidated into the statement of financial position. In general, a VIE is a corporation, partnership, trust, or any other legal structure used for business purposes that either (a) does not have equity investors with voting rights or (b) has equity investors that do not provide sufficient financial resources for the entity to support its activities.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_LongTermMaturities">
    <definition>Carrying value as of the balance sheet date of debt (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedLiability">
    <definition>Estimated liability to settle asbestos claims in more than one year.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EmployeeServiceShareBasedCompensationUnrecognizedCompensationCostsOnNonvestedAwards">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_BusinessAcquisitionContingentConsiderationAtFairValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommonStockSharesIssued">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedReservesSensitivityImpactOnLiability">
    <definition>The estimated amount that a 25% increase in the average asbestos-related claim indemnity settlement amount would increase the asbestos-related liability.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FiniteLivedIntangibleAssetsNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NetCashProvidedByUsedInFinancingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherAssetsNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RollingAsbestosRelatedLiabilityEstimate">
    <definition>Rolling Asbestos Related Liability Estimate</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_CancellationOfCommonSharesAndIssuanceOfRegisteredShares">
    <definition>Value of stock that was converted from one type or class to another during the period. Conversion may be among classes of common or nonredeemable preferred stock or from common stock or nonredeemable preferred stock to nonredeemable preferred stock or common stock, respectively.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_VariableInterestEntitiesCarryingAmountOfOtherAssetsConsolidatedVies">
    <definition>The aggregate carrying amount of all the variable interest entities' assets, other than current assets, consolidated into the statement of financial position. In general, a VIE is a corporation, partnership, trust, or any other legal structure used for business purposes that either (a) does not have equity investors with voting rights or (b) has equity investors that do not provide sufficient financial resources for the entity to support its activities.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PrepaidTaxes">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeAssetNotDesignatedAsHedgingInstrumentFairValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StandardProductWarrantyAccrualWarrantiesIssued">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_EquityMethodInvestmentSummarizedBalanceSheetDataTextBlock">
    <definition>This element represents disclosure of summarized balance sheet data for equity method investees including, current assets, other assets, current liabilities and net assets.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_EquityMethodInvestmentSummarizedIncomeStatementDataTextBlock">
    <definition>This element represents disclosure of summarized income statement data for equity method investees including, total revenues, gross profit, income before income taxes, and net earnings.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NetCashProvidedByUsedInInvestingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DebtServiceLetterOfCreditRelatedPartyDisclosure">
    <definition>Describes certain required disclosures for debt service reserve letter of credit to cover debt payments of equity investee.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityRegistrantName">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedRangeOfPossibleEstimatedLoss">
    <definition>The most likely estimated possible loss from asbestos-related claims should the ruling that pleureal palque claims do not amount to a compensable injury be reversed.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedAccrualCarryingValuePaymentsExpectedToBeFundedByCompany">
    <definition>The payments expected to be made in the annual fiscal period funded by the company as a result of expected asbestos-related indemnity and defense costs exceeding expected insurance settlement proceeds.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CommonStockSharesOutstanding">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedPendingClaimsNumberEndingBalance">
    <definition>The total number of open claims as of the balance sheet date.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedReservesSensitivityImpactOnLiabilityMinimum">
    <definition>Additional expense that would be recognized in the statement of operations for a 25% increase in the average asbestos-related claim indemnity settlement amount based on the increase in the asbestos-related liability balance and assuming no change in the assumptions currently used to estimate the asbestos-related insurance asset.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GuaranteeObligationsCurrentCarryingValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedAsConditionalCapital">
    <definition>The number of registered shares authorized as conditional capital for the issuance of registered shares under share-based compensation plans, outstanding share purchase warrants and other convertible securities that may be issued in the future.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RollforwardOfTemporaryEquityTextBlock">
    <definition>A rollfoward of temporary equity from the beginning of the period to the end of the period.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_BasisOfPresentationPolicyTextBlock">
    <definition>Description of presentation of financial statements which includes the fiscal year and/or quarter for parent company, as well as, the U.S. and non-U.S. operations, the basis of accounting used to prepare the financial statements and the impact any new accounting pronouncements may have on the basis of presentation.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentOwnershipPercentage">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_Goodwill">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_MinorityInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationGrossProfitLoss">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfIntangibleAssetsAmortizationByYearTextBlock">
    <definition>The amount of amortization expense expected to be recognized over the next five years.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_RetainedEarningsAccumulatedDeficit">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LongTermDebtAndCapitalLeaseObligations">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_NetAsbestosRelatedProvisionGain">
    <definition>Net (gain)/loss for charges on the revaluation of the asbestos liability and related asset.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_OtherAccountsAndNotesReceivableNet">
    <definition>Includes insurance claims, interest, dividends, foreign refundable value added taxes and security/other deposits that are anticipated to be collected within one year and the current portion of the asbestos-related insurance recovery receivable.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_NetAsbestosRelatedGainProvision">
    <definition>The adjustment to exclude the noncash portion of asbestos related activities.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeLiabilityNotDesignatedAsHedgingInstrumentFairValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_CurrentMaturities">
    <definition>Carrying value as of the balance sheet date of the portion of long-term debt that is scheduled to be repaid within one year or the normal operating cycle, if longer.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LongTermAccountsNotesAndLoansReceivableNetNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ContractsRevenue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EarningsPerShareBasic">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityCommonStockSharesOutstanding">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_OtherIntangibleAssetsAmortizationPeriodMinimum">
    <definition>Other Intangible Assets Amortization Period Minimum</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PrincipalAmountOnChinaBasedSubsidiaryLoan">
    <definition>Principal Amount On China Based Subsidiary Loan</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPeriodIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedAccrualAtCarryingValueRelatedToFutureUnassertedClaims">
    <definition>The carrying amount as of the balance sheet date of the portion of the combined total of asbestos-related indemnity and defense costs related to estimated future unasserted claims.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IncomeLossBeforeIncomeTaxes">
    <definition>Sum of operating profit and nonoperating income (expense) before income taxes and including the portion attributable to noncontrolling interest.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_NotionalAmountOfForeignCurrencyDerivatives">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DebtInstrumentInterestRateStatedPercentageTermLoanChina">
    <definition>Interest rate stated in the contractual debt agreement on Chinese term loan.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_BusinessAcquisitionContingentConsiderationPotentialCashPayment">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
</DefinitionAndReference>
