<DefinitionAndReference>
  <Element Id="us-gaap_Assets">
    <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_DebtInstrumentInterestRateStatedPercentage">
    <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="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="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_IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions">
    <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_DefinedBenefitPlanAmortizationOfTransitionObligationsAssets">
    <definition>No authoritative reference available.</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_FiniteLivedIntangibleAssetsNet">
    <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="us-gaap_StandardProductWarrantyAccrual">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesIssuanceOfEquityBySubsidiaryToNoncontrollingInterests">
    <definition>No authoritative reference available.</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="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_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_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease">
    <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_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_CashAndCashEquivalentsPeriodIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_TreasuryStockShares">
    <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="us-gaap_GuaranteeObligationsUnlimitedExposure">
    <definition>No authoritative reference available.</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_ScheduleOfRecoveryOfCommercialClaimsTextBlock">
    <definition>This table includes : (1)The 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 and (2) 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="us-gaap_OtherComprehensiveIncomeAmortizationOfDefinedBenefitPlanNetPriorServiceCostCreditRecognizedInNetPeriodicBenefitCostBeforeTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ProceedsFromMinorityShareholders">
    <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_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="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="us-gaap_DepreciationDepletionAndAmortization">
    <definition>No authoritative reference available.</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="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_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="fwlt_AsbestosRelatedOpenClaimsRollforwardTableTextBlock">
    <definition>This element captures the activity for open asbestos-related claims for the period.</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_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="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures">
    <definition>No authoritative reference available.</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="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_TreasuryStockValueAcquiredCostMethod">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DefinedBenefitPlanExpectedRemainingEmployerContributionsForPeriod">
    <definition>The employer's best estimate of contributions expected to be paid to the plan for the remainder of the fiscal year. Estimated contributions may be presented in the aggregate combining (1) contributions required by the funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions.</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_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_PensionAndOtherPostretirementBenefitsDisclosureTextBlock">
    <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="dei_EntityCentralIndexKey">
    <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="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_ReceivablesPolicyTextBlock">
    <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="fwlt_AsbestosRelatedReservesSensitivtyImpactOnEarningsRange">
    <definition>Percentage of the asbestos related liability reserve that would result in an additional expense to be recognized in the statement of operations for a 25% increase in the average asbestos-related claim indemnity settlement amount 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_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 accrued profit exceeded a million.</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_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_ConsolidationPolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityCurrentReportingStatus">
    <definition>No authoritative reference available.</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="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="fwlt_ScheduleOfGoodwillByGeographicRegionTableTextBlock">
    <definition>This element represents the goodwill disclosure by geographic region for the period, by reportable segment and in total.</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_RestrictedCashAndCashEquivalentsNoncurrent">
    <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_WeightedAverageNumberOfSharesOutstandingBasic">
    <definition>No authoritative reference available.</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="fwlt_TotalTemporaryEquity">
    <definition>TOTAL TEMPORARY EQUITY</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="dei_EntityFilerCategory">
    <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_NetIncomeLoss">
    <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_GuaranteeObligationsCurrentCarryingValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedPendingClaimsNumber">
    <definition>The total number of open claims as of the balance sheet date.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_EquityInNetEarningsOfUnconsolidatedAffiliates">
    <definition>This amount represents the entity's proportionate share for the period of the 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.</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="us-gaap_RelatedPartyTransactionRevenuesFromTransactionsWithRelatedParty">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_USAsbestosRelatedPaymentsAndInsuranceSettlementProceedsTableTextBlock">
    <definition>U.S. Asbestos-Related Payments And Insurance Settlement Proceeds</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_TreasuryStockValue">
    <definition>No authoritative reference available.</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="us-gaap_AccruedIncomeTaxesCurrent">
    <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="us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments">
    <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="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_IncreaseDecreaseInOtherOperatingCapitalNet">
    <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_IncreaseDecreaseInReceivables">
    <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_ContractRevenueCost">
    <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="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_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax">
    <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="us-gaap_EmployeeServiceShareBasedCompensationUnrecognizedCompensationCostsOnNonvestedAwards">
    <definition>No authoritative reference available.</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_BillingsInExcessOfCost">
    <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_ReceivablesLongTermContractsOrPrograms">
    <definition>No authoritative reference available.</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="us-gaap_CommonStockValue">
    <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_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="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTextBlock">
    <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="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_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="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_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentLiabilities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedReservesPercentInSensitivityImpactOnLiability">
    <definition>Sensitivity analysis estimate used for the percentage increase/decrease of the entity's average per claim indemnity settlement amount when quantifying the impact on the asbestos liability.</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="us-gaap_TemporaryEquityCarryingAmount">
    <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_LiabilitiesAndStockholdersEquity">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_EquityInNetEarningsOfPartiallyOwnedAffiliatesTextBlock">
    <definition>This item represents the entity's proportionate share for the period of the 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.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DefinedBenefitPlanEstimatedFutureEmployerContributionsCurrentFiscalYear">
    <definition>The employer's best estimate of contributions expected to be paid to the plan in the current fiscal year. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions.</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_PrepaidTaxes">
    <definition>No authoritative reference available.</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_ScheduleOfGuaranteeObligationsTextBlock">
    <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_ScheduleOfFiniteLivedIntangibleAssetsByMajorClassTextBlock">
    <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_FutureAmortizationExpenseYearThree">
    <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_AsbestosRelatedAccruedExpensesCurrent">
    <definition>Estimated liability due within one year to settle asbestos claims.</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_EquityMethodInvestments">
    <definition>No authoritative reference available.</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="us-gaap_GainLossOnSaleOfOtherAssets">
    <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_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 asbestos-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_EquityMethodInvestmentFinancialDataTextBlock">
    <definition>Schedule of summarized balance sheet and income statement data for equity method investees.</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="us-gaap_InterestExpenseDebt">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_OperatingRevenuesByIndustryAndByBusinessSegmentTableTextBlock">
    <definition>Operating revenues from third-parties disclosed by industry and by business segment.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CashFlowHedgeGainLossReclassifiedToInterestExpenseNet">
    <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 purchase order as a result of our alleged failures.</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 to-date.</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_DerivativeLiabilityDesignatedAsHedgingInstrumentFairValue">
    <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="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="us-gaap_ProceedsFromSaleOfOtherAssets">
    <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="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="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue">
    <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="fwlt_AmountOfCreditFacilityAvailable">
    <definition>Amount Of Credit Facility 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="fwlt_ScheduleOfEarningsPerShareBasicAndDilutedTextBlock">
    <definition>Schedule of earnings per share basic and diluted.</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="us-gaap_InvestmentIncomeInterest">
    <definition>No authoritative reference available.</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="fwlt_ContractProfitCorrections">
    <definition>The current period impact of out-of-period corrections related to the reduction of final estimated profit. The corrections were recorded in the current period as they were not material to previously issued financial statements, nor are they expected to be material to the current full year financial statements.</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_EquityMethodInvestmentSummarizedFinancialInformationNetSalesOrGrossRevenue">
    <definition>No authoritative reference available.</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_RetirementOfRegisteredSharesUnderRegisteredShareRepurchaseProgramPolicyTextBlock">
    <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="us-gaap_DefinedBenefitPlanContributionsByEmployer">
    <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="fwlt_RegisteredSharesToBeAcquiredAdditionalRepurchaseAuthorization">
    <definition>Additional U.S. dollar value of outstanding shares that may be purchased under publicly announced share repurchase program</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_LongTermAccountsNotesAndLoansReceivableNetNoncurrent">
    <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="us-gaap_BusinessAcquisitionDescriptionOfAcquiredEntity">
    <definition>No authoritative reference available.</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_GuaranteeObligationsMaximumExposure">
    <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_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_UnconsolidatedAffiliateInsuranceRecoveryAssessmentReceivableCurrent">
    <definition>Receivable related to the remaining balance under an unconsolidated affiliate's insurance recovery assessment for a claim for reimbursement due to a loss suffered by the unconsolidated affiliate that is covered under their insurance policy. For classified balance sheets, represents the current amount receivable, that is amounts expected to be collected within one year or the normal operating cycle, if longer.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_BusinessAcquisitionCostOfAcquiredEntityCashPaid">
    <definition>No authoritative reference available.</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_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="us-gaap_SignificantAccountingPoliciesTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_USNetAsbestosRelatedProvisionTableTextBlock">
    <definition>U.S. Net Asbestos-related provision</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GainLossRelatedToLitigationSettlement">
    <definition>No authoritative reference available.</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="dei_DocumentFiscalPeriodFocus">
    <definition>No authoritative reference available.</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_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_ProjectsWithFinalEstimatedContractProfitRevisionsWhoseImpactExceeds1MillionTextBlock">
    <definition>This table includes :  (1) The number of separate projects that had final estimated contract profit revisions whose impact on accrued profit exceeded $1 million and (2) the current period impact 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="fwlt_RefineryPowerGenerationProjectInChileTextBlock">
    <definition>This table includes; (1) the revenues, net of returns and allowances, realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period and (2) the aggregate amount of receivables to be collected from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth, at the financial statement date. which are usually due within one year (or one business cycle).</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="us-gaap_OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlanNetTransitionAssetObligationRecognizedInNetPeriodicBenefitCostBeforeTax">
    <definition>No authoritative reference available.</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_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedAccrualPaymentsExpectedToBeReceivedFundedByCompany">
    <definition>The payments expected to be received/(made) in the annual fiscal period funded by the company as a result of expected asbestos-related indemnity and defense costs falling below/(exceeding) expected insurance settlement proceeds.</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_DefinedBenefitPlanExpectedReturnOnPlanAssets">
    <definition>No authoritative reference available.</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_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments">
    <definition>No authoritative reference available.</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="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_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities">
    <definition>No authoritative reference available.</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_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="fwlt_AsbestosRelatedAccrualPaymentFundedProceedsReceivedByCompany">
    <definition>The net cash outflows/(inflows) as a result of current period activity related to payments for asbestos-related indemnity and defense costs and cash receipts from insurance settlement proceeds.</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="us-gaap_AssetsCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ShareBasedCompensationExpenseAndRelatedTaxTextBlock">
    <definition>This table includes : (1)  the expense recognized during the period arising from share-based compensation arrangements (for example, shares of stock, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees, and (2) the total recognized tax benefit related to compensation cost for share-based payment arrangements recognized in income during the period.</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_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="fwlt_FutureIncrementalIncreasesPermittedUnderCreditAgreement">
    <definition>The future incremental increases to the secured credit facility permitted by the credit agreement.</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_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="dei_DocumentFiscalYearFocus">
    <definition>No authoritative reference available.</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="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="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock">
    <definition>No authoritative reference available.</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_DefinedBenefitPlanInterestCost">
    <definition>No authoritative reference available.</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_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_CommonStockSharesAuthorized">
    <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="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="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="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_DefinedBenefitPlanServiceCost">
    <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="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="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="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired">
    <definition>No authoritative reference available.</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_VariableInterestEntityOwnershipPercentage">
    <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="us-gaap_CommonStockSharesIssued">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EmployeeServiceShareBasedCompensationUnrecognizedCompensationCostsOnNonvestedAwardsWeightedAveragePeriodOfRecognition">
    <definition>No authoritative reference available.</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_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="dei_DocumentPeriodEndDate">
    <definition>No authoritative reference available.</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="us-gaap_StandardProductWarrantyAccrualWarrantiesIssued">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedInsuranceProceeds">
    <definition>The amount of asbestos-related insurance proceeds in the period.</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="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 pleural plaque claims do not amount to a compensable injury be reversed.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedAccrualCarryingValuePayments">
    <definition>The payments for asbestos litigation, defense and case resolution during the period.</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_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements">
    <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="us-gaap_ProfitLoss">
    <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 rollforward 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="us-gaap_FutureAmortizationExpenseYearFive">
    <definition>No authoritative reference available.</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_MinorityInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityWellKnownSeasonedIssuer">
    <definition>No authoritative reference available.</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="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_ScheduleOfContributionsDefinedBenefitPensionPlanTableTextBlock">
    <definition>Schedule Of Contributions Defined Benefit Pension Plan [Table Text Block]</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_EquityMethodInvestmentDividendsOrDistributions">
    <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_ContractsRevenue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GoodwillAcquiredDuringPeriod">
    <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="us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity">
    <definition>No authoritative reference available.</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_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="us-gaap_CommonStockSharesOutstanding">
    <definition>No authoritative reference available.</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="us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation">
    <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>
</DefinitionAndReference>
