<DefinitionAndReference>
  <Element Id="us-gaap_PercentageOfDebtHedgedByInterestRateDerivatives">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ConvertiblePreferredStockSharesIssuedUponRedomestication">
    <definition>Number of registered shares issued for each share of convertible preferred stock upon Redomestication.</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_GuaranteeObligationsUnlimitedExposure">
    <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_ConstructionInProgressGross">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue">
    <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_CapitalLeasesFutureMinimumPaymentsDueTableTextBlock">
    <definition>The schedule of future contractually required rental payments on leases meeting the criteria for capitalization.</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="us-gaap_ScheduleOfEntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesByCountryTextBlock">
    <definition>No authoritative reference available.</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_DebtInstrumentFairValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber">
    <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="us-gaap_InterestCostsIncurred">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_GoodwillGross">
    <definition>Gross amount, as of the balance sheet date, of the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable), in excess of the fair value of net assets acquired in one or more business combination transactions.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AmountOfTermLoanNewlyIssued">
    <definition>Amount of Term Loan Newly Issued</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfExpectedBenefitPaymentsTableTextBlock">
    <definition>Disclosure of benefits expected to be paid by pension plans and/or other employee benefit plans in each of the next five fiscal years and in the aggregate for the five fiscal years thereafter.</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_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock">
    <definition>Disclosure of the components of income tax expense attributable to continuing operations for each year presented including, but not limited to: current tax expense (benefit), deferred tax expense (benefit), investment tax credits, government grants, the benefits of operating loss carryforwards, tax expense that results from allocating certain tax benefits either directly to contributed capital or to reduce goodwill or other noncurrent intangible assets of an acquired entity, adjustments of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity, and adjustments of the beginning-of-the-year balances of a valuation allowance because of a change in circumstances that causes a change in judgment about the realizability of the related deferred tax asset in future years.</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_StockRepurchasedAndRetiredDuringPeriodValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_CancellationOfCommonSharesAndIssuanceOfRegisteredSharesShares">
    <definition>Number of shares issued during the period as a result of cancellation of common shares and issuance of registered shares.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_EffectiveIncomeTaxRateReconciliationNondeductibleLossNontaxableIncome">
    <definition>The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to either losses that are nondeductible for tax purposes or income that is exempt from income taxes under enacted tax laws.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice">
    <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_EarningsPerShareBasic">
    <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="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_CommonStockSharesIssued">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit">
    <definition>No authoritative reference available.</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_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_OperatingLeasesFutureMinimumPaymentsDueInThreeYears">
    <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_CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation">
    <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_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="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsInYearTwo">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LongTermContractsOrProgramsDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ValuationAllowancesAndReservesDeductions">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LongTermDebtNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansTax">
    <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="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate">
    <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="dei_DocumentType">
    <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_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm">
    <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="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_DebtDisclosureTextBlock">
    <definition>No authoritative reference available.</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_TreasuryStockSharesAcquired">
    <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_PercentageOfRedemptionEqualToPrincipal">
    <definition>Percentage of Redemption Equal to Principal</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LegalFees">
    <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_FutureAmortizationExpenseYearOne">
    <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_StandardProductWarrantyAccrualPayments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions">
    <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="dei_EntityCommonStockSharesOutstanding">
    <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_GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_InvestmentsInAndAdvanceToUnconsolidatedSubsidiariesPolicyTextBlock">
    <definition>This element describes an entity's application of the equity method of accounting to investments in common stock or other interests including unconsolidated domestic subsidiaries, corporate joint ventures, noncontrolling interests in real estate ventures, limited partnerships, and limited liability companies. Additionally, this element describes the entity's application of the cost method of accounting for investments or other interests that are not consolidated or accounted for under the equity method of accounting.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAmortizationOfNetGainsLosses">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanActuarialNetGainsLosses">
    <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="us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanFairValueOfPlanAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RestrictedCashTextblock">
    <definition>Restricted Cash Textblock</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="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_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="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="fwlt_WeightedAverageAssumptionsToEstimateFairValueOfOptionGrantsTextBlock">
    <definition>Disclosure of assumptions used to determine the fair value of stock options granted.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredTaxAssetsLiabilitiesNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAmortizationOfNetTransitionAssetObligation">
    <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_PropertyPlantAndEquipmentDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DeferredTaxAssetsAsbestosClaims">
    <definition>The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from asbestos claims which can only be deducted for tax purposes when the claims are paid, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsInFiveFiscalYearsThereafter">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DebtInstrumentInterestRateTermsOnUnhedgedBalances">
    <definition>The interest rate on the unhedged portions of FW Power VAT and base facilities.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardRestrictedSharesNonvestedNumber">
    <definition>The number of outstanding restricted shares 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_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions">
    <definition>No authoritative reference available.</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="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance">
    <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="us-gaap_ScheduleOfDerivativeInstrumentsGainLossInStatementOfFinancialPerformanceTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PercentageOfThirdPartyOperatingRevenues">
    <definition>The percentage of third-party operating revenues that each region represents as compared to total operating revenues.  Calculated for each member as a percentage of the total for the business segment and consolidated total.</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_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest">
    <definition>No authoritative reference available.</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_PaymentsOfDividendsMinorityInterest">
    <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="fwlt_StockholdersEquityNoteStockSplitPolicyTextBlock">
    <definition>Description of the stock split arrangement. Also provide the retroactive effect given by a stock split for all periods presented in the financial statements.</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_LoansNotesTradeAndOtherReceivablesDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IssuanceOfCommonSharesUponExerciseOfSharePurchaseWarrantsShares">
    <definition>Number of common shares issued during the period as a result of the conversion of convertible securities.</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_USAsbestosRelatedPaymentsAndInsuranceSettlementProceedsTableTextBlock">
    <definition>U.S. Asbestos-Related Payments And Insurance Settlement Proceeds</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_DeferredTaxLiabilitiesUndistributedForeignEarnings">
    <definition>No authoritative reference available.</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_EntityWideDisclosureOnGeographicAreasRevenueFromExternalCustomersAttributedToIndividualForeignCountriesAmount">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanPlanAmendments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsImpairmentLosses">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeAssetDesignatedAsHedgingInstrumentFairValue">
    <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="fwlt_RestrictionsOnShareholdersDividendsPolicyTextBlock">
    <definition>Terms of restrictions on declaring cash dividends under credit agreement.</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_OtherLiabilitiesNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfComprehensiveIncomeLossTableTextBlock">
    <definition>Disclosure of components of comprehensive income (loss) including, but not limited to: (a) foreign currency translation adjustments; (b) gains and losses on foreign currency transactions that are designated as, and are effective as, economic hedges of a net investment in a foreign entity; (c) gains and losses on intercompany foreign currency transactions that are of a long-term-investment nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements; (d) change in the market value of a futures contract that qualifies as a hedge of an asset reported at fair value; (e) unrealized holding gains and losses on available-for-sale securities and that resulting from transfers of debt securities from the held-to-maturity category to the available-for-sale category; (f) a net loss recognized as an additional pension liability not yet recognized as net periodic pension cost; and (g) the net gain or loss and net prior service cost or credit for pension plans and other postretirement benefit plans.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock">
    <definition>Disclosure of the combined aggregate amount of maturities and sinking fund requirements for all long-term borrowings for each of the five years following the date of the latest balance sheet date presented.</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="fwlt_EquityMethodInvestmentUndistributedRetainedEarnings">
    <definition>This item represents the company's share of undistributed retained earnings of equity investees at the balance sheet date.</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="us-gaap_DueFromRelatedPartiesCurrent">
    <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_AsbestosRelatedPendingClaimsNotValuedInLiability">
    <definition>The number of pending asbestos claims not valued in the asbestos liability as of the balance sheet date.</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="dei_CurrentFiscalYearEndDate">
    <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="us-gaap_NetCashProvidedByUsedInOperatingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DeferredTaxAssetsAccruedCostsOnLongTermContracts">
    <definition>The tax effect as of the balance sheet date of the amount of the estimated future tax deductions attributable to expenses recognized only under generally accepted accounting principles and which will reverse when recognized for tax purposes .</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnAccumulatedPostretirementBenefitObligation">
    <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_BusinessAcquisitionNameOfAcquiredEntity">
    <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_CurrentIncomeTaxExpenseBenefit">
    <definition>No authoritative reference available.</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="us-gaap_FutureAmortizationExpenseYearTwo">
    <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="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_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPeriodIncreaseDecrease">
    <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="dei_AmendmentFlag">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ContractReceivableRetainageDueThreeToFourYears">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanFundedStatusOfPlan">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumNumberOfSharesToBeIssuedUnderPlan">
    <definition>The maximum number of shares originally approved (usually by shareholders and board of directors), plus any additional shares that become available pursuant to the terms of the awards previously granted under the prior compensation plans and oustanding as of the date of the plan and only if those awards expire, terminate or are otherwise forfeited before being exercised or settled in full.</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="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanTargetAllocationPercentage">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedPercentageOfLawsuitsNotSpecifyingMonetaryDamagesSought">
    <definition>Approximate percentage of lawsuits that do not specify monetary damages sought or merely recite that the amount of monetary damages sought meets or exceeds the required jurisdictional minimum.</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="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ContingenciesAndCommitments">
    <definition>Represents the caption on the face of the balance sheet to indicate that the entity has entered into (1) supply or purchase arrangements that will require expending a portion of its resources to meet the terms thereof, and (2) is exposed to potential losses or, less frequently, gains, arising from (a) possible claims against a company's resources due to future performance under contract terms, and (b) possible losses or likely gains from uncertainties that will ultimately be resolved when one or more future events that are deemed likely to occur do occur or fail to occur. This caption alerts the reader that one or more notes to the financial statements disclose pertinent information about the entity's commitments and contingencies.</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="fwlt_DefinedBenefitPlanOtherChangesInFairValueOfPlanAssets">
    <definition>The amount of increase or decrease in plan assets attributed to other changes.</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_TreasuryStockValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments">
    <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="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_DeferredTaxAssetsGross">
    <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_DefinedBenefitPlanContributionsByPlanParticipants">
    <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="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits">
    <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_LiabilitiesAndStockholdersEquity">
    <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="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SegmentReportingInformationExpendituresForAdditionsToLongLivedAssets">
    <definition>No authoritative reference available.</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_ScheduleOfRevenueFromExternalCustomersAttributedToNonUSCountriesBasedOnSubsidiaryLocationTextBlock">
    <definition>This element may be used to disclose in its entirety the names of non-U.S. countries from which operating revenue is material and the amount of operating revenue from external customers attributed to those countries based on where the contracting subsidiary is located rather than the customer location.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_GoodwillImpairedAccumulatedImpairmentLoss">
    <definition>The accumulated impairment losses related to goodwill as of the balance sheet date.</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_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsInYearThree">
    <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_ScheduleOfGuaranteeObligationsTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_CommonStockSharesIssuedByFormerParent">
    <definition>Common stock of former parent entity issued to continuing parent entity.</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_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_ProceedsFromIssuanceOfLongTermDebt">
    <definition>No authoritative reference available.</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_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax">
    <definition>No authoritative reference available.</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="fwlt_UnrecognizedTaxBenefitsNetInterestOnIncomeTaxesExpense">
    <definition>This element represents net interest expense recognized for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity offset by previously accrued interest expense on uncertain tax positions which were ultimately not assessed.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RestrictedCashDebtServicePayments">
    <definition>Restricted cash held by special-purpose entities and restricted for debt service payments.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PensionPlanAssetsCashEquivalents">
    <definition>The total of pension plan cash and cash equivalents</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_AccumulatedOtherComprehensiveIncomeLossNetOfTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets">
    <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_StockIssuedDuringPeriodValueStockOptionsExercised">
    <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_EquityMethodInvesteeImpairmentCharge">
    <definition>Impact on equity income/loss for an impairment charge recorded on the financial statements of an equity method investee.</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_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CapitalLeaseObligationsNoncurrent">
    <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="us-gaap_ConsolidationPolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_CertainComponentsOfEbitdaTableTextBlock">
    <definition>Pre-tax items included in EBITDA and Net Income attributable to registrant.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SaleLeasebackTransactionCurrentPeriodGainRecognized">
    <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="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_EquityMethodInvestments">
    <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_SegmentReportingInformationInvestmentInEquityMethodInvestees">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_FurnitureAndFixturesGross">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_IncomeTaxExaminationLiabilityRefundAdjustmentFromSettlementWithTaxingAuthority">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized">
    <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="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue">
    <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_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock">
    <definition>For operating leases having initial or remaining noncancelable lease terms in excess of one year, the lessee shall disclose both: future minimum payments required as of the date of the latest balance sheet presented, in the aggregate and for each of the five succeeding fiscal years and the total minimum rentals to be received in the future under noncancelable subleases as of the date of the latest balance sheet presented.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_NetChangeInAsbestosRelatedAssetsAndLiabilities">
    <definition>The net change during the period in the amount of cash payments due to asbestos-related liability</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PensionPlanAssetsInvestedInCashEquivalentCommingledFunds">
    <definition>The fair value of the pension plan assets that are invested in cash equivalent commingled funds.</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_ScheduleOfSegmentReportingInformationBySegmentTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CapitalLeasesLesseeBalanceSheetAssetsByMajorClassBuilding">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetTransitionAssetsObligationsBeforeTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredIncomeTaxExpenseBenefit">
    <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="fwlt_EntityWideRevenueMajorCustomerPercentOfFlowThroughRevenue">
    <definition>Percentage of flow-through revenue (reimbursable costs, no margin) included in the operating revenue generated from the single external customer that accounts for 10-percent or more of an entity's revenues.</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_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions">
    <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="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_DefinedBenefitPlanUltimateHealthCareCostTrendRate">
    <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_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_AllowanceForDoubtfulAccountsReceivableCurrent">
    <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_FiniteLivedIntangibleAssetsNet">
    <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="fwlt_ScheduleOfNetPeriodicPensionCostCreditDefinedBenefitPensionPlanTextBlock">
    <definition>Schedule Of Net Periodic Pension Cost (Credit), Defined Benefit Pension Plan [Text Block]</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_SettlementChargeRecognizedOnRemeasurementOfTransitionalAsset">
    <definition>Settlement Charge Recognized On The Remeasurement Of Transitional Asset</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAmortizationOfNetPriorServiceCostCredit">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanSpecialTerminationBenefits">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OperatingLeasesFutureMinimumPaymentsDue">
    <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_UnremittedEarningsOfSubsidiariesDeemedToBePermanentlyReinvested">
    <definition>Unremitted earnings of subsidiaries, that have been, or are intended to be, permanently reinvested (and for which no incremental income tax has been provided).</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DerivativeAverageFixedInterestRate">
    <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_IncreaseDecreaseInPensionAndPostretirementObligations">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleofsharebasedcompensationrestrictedStockUnitsAwardActivityTableTextBlock">
    <definition>Disclosure of the number and weighted-average grant date fair value for restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock units that were granted, vested, or forfeited during the year.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_OtherPostretirementDefinedBenefitPlansSipAssets">
    <definition>This represents the asset recognized in the balance sheet that is used to fund the benefit obligations of the Survivor Income Plan.  The asset value represents the cash surrender value of insurances policies purchased to cover the Survivor Income Plan obligations.</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_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount">
    <definition>No authoritative reference available.</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_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_DeferredTaxLiabilitiesNoncurrent">
    <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_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherInventorySupplies">
    <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_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue">
    <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_OtherAssetsCurrent">
    <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="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest">
    <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="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic">
    <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_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent">
    <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="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding">
    <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_SeveranceCosts">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PropertyPlantAndEquipmentGross">
    <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_AsbestosRelatedLiability">
    <definition>Estimated liability to settle asbestos claims in more than one year.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_CommonSharesOutstandingCancelledAndReissued">
    <definition>Common Shares Outstanding Cancelled And Reissued</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PensionPlanAssetsInvestedInCorporateFixedIncomeCommingledFunds">
    <definition>The fair value of the pension plan assets that are invested in corporate fixed-income commingled funds which consist primarily of corporate fixed income securities with a focus on intermediate-term and long-term maturities.</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="us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter">
    <definition>No authoritative reference available.</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_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardRestrictedSharesNonvestedWeightedAverageGrantDateFairValue">
    <definition>The weighted average fair value of nonvested restricted shares 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="fwlt_PensionPlanAssetsPlanReceivables">
    <definition>The total of pension plan receivables</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SaleLeasebackTransactionDeferredGainNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTextBlock">
    <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_OperatingLeasesFutureMinimumPaymentsDueCurrent">
    <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="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PostiveSettlementsFromArbitrationAwards">
    <definition>Receipt of payment on a long outstanding arbitration award settled in favor of our subsidiary in our Global Engineering and Construction Group</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_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccountsReceivableGrossCurrent">
    <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="dei_EntityRegistrantName">
    <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_BuildingsAndImprovementsGross">
    <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_StandardProductWarrantyAccrual">
    <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_OtherComprehensiveIncomeAmortizationOfDefinedBenefitPlanNetPriorServiceCostCreditRecognizedInNetPeriodicBenefitCostBeforeTax">
    <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="us-gaap_DeferredTaxAssetsValuationAllowance">
    <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_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_RepaymentsOfShortTermDebt">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IssuanceOfRegisteredSharesUponConversionOfPreferredSharesShares">
    <definition>Number of shares 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="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue">
    <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_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_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_OtherNontradeReceivablesCurrent">
    <definition>Other amounts currently receivable from third-parties. For classified balance sheets, represents the current other receivables, that are amounts expected to be collected within one year.</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_PensionPlanAssetsInvestedInEquitySecurities">
    <definition>The fair value of the pension plan assets that are invested in equity securities which consist primarily of publicly traded equity securities.</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="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease">
    <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_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments">
    <definition>No authoritative reference available.</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_MinorityInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock">
    <definition>Disclosure of the components of net deferred tax asset or liability recognized in an entity's statement of financial position, including the following: the total of all deferred tax liabilities, the total of all deferred tax assets, the total valuation allowance recognized for deferred tax assets.</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="fwlt_CertainComponenetsOfEbitdaTableTextBlock">
    <definition>Pre-tax items included in EBITDA and Net Income attributable to registrant.</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="us-gaap_ProfitLoss">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InventoryPolicyTextBlock">
    <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_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_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod">
    <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_OperatingLeasesFutureMinimumPaymentsDueInTwoYears">
    <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_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PaymentsOfFinancingCosts">
    <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_SellingGeneralAndAdministrativeExpense">
    <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_IncomeTaxExpenseBenefit">
    <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="us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock">
    <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="fwlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardRestrictedSharesVestedInPeriodWeightedAverageGrantDateFairValue">
    <definition>The weighted average fair value as of grant dates pertaining to a restricted share award plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to have all restrictions removed in accordance with the terms of the arrangement.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SegmentReportingInformationEquityInNetIncomeOfEquityMethodInvesteesOfSegment">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_SegmentReportingInformationAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax">
    <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="us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets">
    <definition>No authoritative reference available.</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_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue">
    <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_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_NoncashGainsOnRepaymentOfLongTermDebt">
    <definition>Noncash Gains on Repayment of Long Term Debt</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="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_CapitalLeaseObligationsCurrent">
    <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="fwlt_DefinedBenefitPlanMandatoryContributionsByEmployer">
    <definition>The amount of mandatory contributions made by the employer.</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_ScheduleOfRevenueFromExternalCustomersAttributedToForeignCountriesByGeographicAreaTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment">
    <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="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_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedContributionPlanCostRecognized">
    <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_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PostiveSettlementsOnProjects">
    <definition>Positive settlements received on projects in the period</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="us-gaap_FiniteLivedIntangibleAssetsGross">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PensionPlanAssetsInvestedInEquityCommingledFunds">
    <definition>The fair value of the pension plan assets that are invested in equity commingled funds which consists primarily of  equity securities with a focus on long-term returns.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_SegmentReportingInformationEquityInNetIncomeOfEquityMethodInvesteesOfSegmentTextBlock">
    <definition>Schedule of income or loss recognized by the reportable segment for its share of an investee's net income or loss reported under the equity method of accounting. Must be disclosed if the amount (a) is included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) is otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfExpectedAmortizationExpenseTableTextBlock">
    <definition>Discloses the estimated aggregate amortization expense for each of the five succeeding fiscal years.</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_EquityMethodInvestmentSummarizedFinancialInformationGrossProfitLoss">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares">
    <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="us-gaap_TemporaryEquityCarryingAmount">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DefinedBenefitPensionPlanWithAccumulatedBenefitObligationInExcessOfPlanAssetsTextBlock">
    <definition>Defined Benefit Pension Plan With An Accumulated Benefit Obligation In Excess Of Plan Assets [Text Block]</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYear">
    <definition>No authoritative reference available.</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_InvestmentIncomeInterest">
    <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_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfQuarterlyFinancialInformationTableTextBlock">
    <definition>Disclosure of the quarterly financial data in the annual financial statements as a single block of text. The disclosure includes a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income (loss) before extraordinary items and cumulative effect of a change in accounting principle and earnings per share data.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_GovernmentMandatedIndemnityAndPostretirementProgramsLiability">
    <definition>Government-mandated indemnity and postretirement programs liability</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_IssuanceOfCommonSharesUponConversionOfPreferredSharesShares">
    <definition>Number of shares 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="us-gaap_CapitalLeaseObligations">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ForeignCurrencyTransactionGainLossNetOfTax">
    <definition>The aggregate foreign currency transaction gain or loss (both realized and unrealized) included in determining net income for the reporting period, net of tax.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IssuanceOfCommonSharesUponExerciseOfStockOptionsValue">
    <definition>Value stock issued during the period as a result of the exercise of stock options.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_DebtInstrumentBorrowingCapacityAmount">
    <definition>Amount of borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance-sheet date.</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="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="us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RestrictedCashClientDedicatedAccounts">
    <definition>Restricted cash in client dedicated accounts.</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_ScheduleOfAllocationOfPlanAssetsTableTextBlock">
    <definition>Disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans.  This information may include, but is not limited to: the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall.</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="fwlt_OtherAccountsAndNotesReceivableNetTableTextBlock">
    <definition>Disclosure itemizing the various types of other accounts and notes receivable, and for each the net carrying value as of the balance sheet date.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DebtInstrumentInterestRateTerms">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions">
    <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="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesBeforeTaxPeriodIncreaseDecrease">
    <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_ScheduleOfAssumptionsUsedTableTextBlock">
    <definition>Disclosure of the assumptions used to determine for pension plans and/or other employee benefit plans the benefit obligation and net benefit cost, including assumed discount rates, rate increase in compensation increase, and expected long-term rates of return on plan assets.</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_Depreciation">
    <definition>No authoritative reference available.</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="us-gaap_CashAndCashEquivalentsAtCarryingValue">
    <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_AccountsReceivableBilledForLongTermContractsOrPrograms">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards">
    <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_SegmentReportingDisclosureTextBlock">
    <definition>No authoritative reference available.</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_FutureAmortizationExpenseYearFive">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedPendingClaimsNumberValuedInLiability">
    <definition>The total number of open asbestos claims as of the balance sheet date that are valued in the asbestos liability.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ContractReceivableRetainageDueOneToTwoYears">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_FractionalSharesCancelled">
    <definition>Fractional shares of former parent entity cancelled.</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="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpense">
    <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="fwlt_DefinedBenefitPlanHealthCareCostTrendRatesAssumedTextBlock">
    <definition>Schedule of assumed health-care cost trend rates for other postretirement benefit plans.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LeaseAndRentalExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EffectiveIncomeTaxRateContinuingOperations">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfValuationAndQualifyingAccountsDisclosureTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PaymentForFractionalSharesCancelledPerShare">
    <definition>Payment For Fractional Shares Cancelled Per Share</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_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_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PensionPlanAssetsInvestedInMoneyMarketCommingledFunds">
    <definition>The fair value of the pension plan assets that are invested in money market commingled funds which consist primarily of investments in short-term maturities of two years or less from various issuers with a focus on preservation of capital.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ValuationAllowancesAndReservesBalance">
    <definition>No authoritative reference available.</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_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities">
    <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="fwlt_IssuanceOfCommonSharesUponVestingOfRestrictedAwardsShares">
    <definition>Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesPlanAssets">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RetirementOfRegisteredSharesUnderRegisteredShareRepurchaseProgramPolicyTextBlock">
    <definition>Terms of restrictions on declaring cash dividends under credit agreement.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_CapitalLeasesFutureMinimumPaymentsDueThereafter">
    <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_EntityWideRevenueMajorCustomerPercentOfConsolidatedRevenue">
    <definition>Percentage of consolidated operating revenue (inclusive of flow-through revenues) generated from a single external customer that accounts for 10-percent or more of an entity's consolidated operating revenues.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IssuanceOfCommonSharesUponVestingOfRestrictedAwards">
    <definition>Issuance of common shares upon vesting of restricted awards</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="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanYearThatRateReachesUltimateTrendRate">
    <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="us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnServiceAndInterestCostComponents">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfValuationAndQualifyingAccountsDisclosureTableTextBlock">
    <definition>Schedule of any allowance and reserve accounts (their beginning and ending balances, as well as a reconciliation by type of activity during the period). Disclosure of the required information may be within the footnotes to the financial statements or a supplemental schedule to the financial statements.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax">
    <definition>No authoritative reference available.</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_SignificantAccountingPoliciesTextBlock">
    <definition>No authoritative reference available.</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_AsbestosRelatedLawsuitDamagesSought">
    <definition>Lawsuits displayed by range of damages sought</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IssuanceOfCommonSharesUponConversionOfPreferredSharesValue">
    <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_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_StockIssuedDuringPeriodSharesStockOptionsExercised">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_IssuanceOfCommonSharesUponExerciseOfStockOptionsShares">
    <definition>Number of shares issued during the period as a result of the exercise of stock options.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_CapitalLeasesLesseeBalanceSheetAssetsByMajorClassTableTextBlock">
    <definition>Schedule of the gross and accumulated values for long-lived depreciable assets subject to a lease meeting the criteria for capitalization.</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_CostsInExcessOfBillingsOnUncompletedContractsOrProgramsExpectedToBeCollectedWithinOneYear">
    <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="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="us-gaap_Land">
    <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_IncrementalCommonSharesAttributableToCallOptionsAndWarrants">
    <definition>No authoritative reference available.</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_EarningsPerSharePolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_EntityWideDisclosureOnGeographicAreasLongLivedAssetsInIndividualForeignCountriesAmount">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_QuarterlyFinancialInformationTextBlock">
    <definition>No authoritative reference available.</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="dei_DocumentPeriodEndDate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PropertyPlantAndEquipmentTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue">
    <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_DerivativeLiabilityDesignatedAsHedgingInstrumentFairValue">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod">
    <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_ScheduleOfRentExpenseTableTextBlock">
    <definition>Disclosure of rental expense from operating leases for each period for which an income statement is presented with separate amounts for minimum rentals, contingent rentals, and sublease rentals. Rental payments under leases with terms of a month or less that were not renewed need not be included.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_LegalCostsPolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedPendingClaimsPlaintiffsAssociatedWithAdministrativeAgreements">
    <definition>The number of plaintiffs as of the balance sheet date associated with claims where our subsidiaries are respondents wherein we have administrative agreements and are named defendants in lawsuits.</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_DeferredTaxLiabilities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities">
    <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="fwlt_RedomesticationDisclosureTextBlock">
    <definition>Redomestication Disclosure [Text Block]</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OperatingLeasesOfLesseeDisclosureTextBlock">
    <definition>No authoritative reference available.</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_EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities">
    <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="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_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_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriod">
    <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_DisclosureOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTextBlock">
    <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="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo">
    <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="us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsInYearFive">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_RestrictedCashLettersOfCreditAndBankGuarantees">
    <definition>Restricted cash held to collateralize letters of credit and bank guarantees.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ContractReceivableRetainageDueOneYearOrLess">
    <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_ValueAddedTaxReceivableCurrent">
    <definition>No authoritative reference available.</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_StandardProductWarrantyAccrualWarrantiesIssued">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ContractReceivableRetainage">
    <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="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPeriodIncreaseDecrease">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GoodwillTranslationAndPurchaseAccountingAdjustments">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm">
    <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="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="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanBenefitsPaid">
    <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="fwlt_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpenseTableTextBlock">
    <definition>Schedule of interest expense and penalties on unrecognized tax benefits</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="us-gaap_OtherAssetsNoncurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_PensionPlanAssetsInvestedInGovernmentFixedIncomeCommingledFunds">
    <definition>The fair value of the pension plan assets that are invested in government fixed-income commingled funds which consist primarily of government fixed-income securities with a focus on current income and capital preservation with varying maturities.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_UnrecognizedTaxBenefitsTextBlock">
    <definition>Rollforward of the balance of unrecognized tax benefits for the period indicated.</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_UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense">
    <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_IntangibleAssetsNetExcludingGoodwill">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredTaxLiabilitiesInvestmentInNoncontrolledAffiliates">
    <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_PrepaidTaxes">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant">
    <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="fwlt_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock">
    <definition>Disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pretax income from continuing operations.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriodWeightedAverageGrantDateFairValue">
    <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_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock">
    <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="fwlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardRestrictedSharesVestedInPeriod">
    <definition>The decrease in the number of restricted shares potentially issuable under a share-based award plan pertaining to awards for which the grantee has gained the right during the reporting period, by satisfying service and performance requirements, to remove the restrictions on the shares in accordance with the terms of the arrangement.</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="us-gaap_AllocatedShareBasedCompensationExpense">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ExtinguishmentOfDebtAmountPaid">
    <definition>Repayment of a portion of the subordinated debt in advance of the maturity date.</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_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_PensionPlanAssetsTotalPlanAssets">
    <definition>The total fair value of pension plan assets</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_GoodwillAndIntangibleAssetsPolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfUnrecognizedCompensationCostNonvestedAwardsTableTextBlock">
    <definition>Disclosure of the total compensation cost related to nonvested awards not yet recognized and the weighted-average period over which it is expected to be recognized.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates">
    <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="us-gaap_InterestExpenseDebt">
    <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="us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax">
    <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_DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnServiceAndInterestCostComponents">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfRevenueFromExternalCustomersByGeographicRegionBasedOnSubsidiaryLocationTextblock">
    <definition>This element may be used to disclose in its entirety the names of geographical regions from which operating revenue is material and the amount of operating revenue from external customers attributed to those regions is based on where the contracting subsidiary is located rather than the customer location.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_UnrecognizedTaxBenefitsNetIncomeTaxPenaltiesExpense">
    <definition>This element represents the recognized net expense for the amount of statutory penalties in the period in which the entity claims or expects to claim a tax position, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties net of previously accrued tax penalties ultimately not assessed.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfEffectOfOnePercentagePointChangeInAssumedHealthCareCostTrendRatesTableTextBlock">
    <definition>Disclosure of the effect of a one-percentage-point increase and the effect of a one-percentage-point decrease in the assumed health care cost trends on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs and the accumulated postretirement benefit obligation for health care benefits.</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_DefinedBenefitPlanExpectedFutureBenefitPaymentsInYearFour">
    <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_IncomeTaxesPaid">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanBenefitObligation">
    <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_GoodwillAcquiredDuringPeriod">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue">
    <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="us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss">
    <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="fwlt_OtherPostretirementDefinedBenefitPlansSipLiabilities">
    <definition>This represents the liability recognized in the balance sheet that is associated with the Survivor Income Plan.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredTaxAssetsNet">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnAccumulatedPostretirementBenefitObligation">
    <definition>No authoritative reference available.</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_DefinedBenefitPlanAccumulatedBenefitObligation">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts">
    <definition>No authoritative reference available.</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="fwlt_DefinedBenefitPlanActualRangeForLongTermReturnOnAssets">
    <definition>The range for the actual weighted-average long-term rate of return earned on plan assets over the last three years.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_UnrecognizedTaxBenefits">
    <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="fwlt_ScheduleOfChangesInProjectedBenefitObligationsTableTextBlock">
    <definition>Disclosure of the change in the benefit obligation of pension plans and/or other employee benefit plans from the beginning to the end of the period, showing separately, if applicable, the effects of the following: service cost, interest cost, contributions by plan participants, actuarial gains and losses, foreign currency exchange rate changes, benefits paid, plan amendments, business combinations, divestitures, curtailments, settlements, and special and contractual termination benefits.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesTaxEffectPeriodIncreaseDecrease">
    <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="us-gaap_AccountsPayableCurrent">
    <definition>No authoritative reference available.</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_ForeignCurrencyDisclosureTextBlock">
    <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_DefinedBenefitPlanContributionsByEmployer">
    <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_EquityMethodInvestmentDividendsOrDistributions">
    <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_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_ReceivablesPolicyTextBlock">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="dei_EntityPublicFloat">
    <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="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease">
    <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="dei_EntityVoluntaryFilers">
    <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="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_InterestPaid">
    <definition>No authoritative reference available.</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>
  <Element Id="us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedPendingClaimsNumberWithAdministrativeAgreements">
    <definition>The total number of open asbestos claims as of the balance sheet date where our subsidiaries are respondents wherein we have administrative agreements and are named defendants in lawsuits.</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="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_DeferredTaxAssetsDeferredIncome">
    <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_LongTermDebtAndCapitalLeaseObligationsCurrent">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock">
    <definition>Disclosure of income before income tax between domestic and foreign jurisdictions.</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_DeferredTaxAssetsOther">
    <definition>No authoritative reference available.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_GainsLossesOnExtinguishmentOfDebt">
    <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="fwlt_SegmentReportingInformationInvestmentInEquityMethodInvesteesTextBlock">
    <definition>Schedule  of investment in an equity method investee of the reportable segment. Must be disclosed if the amount (a) is included in the determination of segment assets reviewed by the chief operating decision maker or (b) is otherwise regularly provided to the chief operating decision maker, even if not included in the determination of segment assets.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="fwlt_AsbestosRelatedLawsuitDamagesSoughtByRangeTextBlock">
    <definition>Schedule showing lawsuits by range of damages sought.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
  <Element Id="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableIntrinsicValue">
    <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="us-gaap_EmployeeServiceShareBasedCompensationUnrecognizedCompensationCostsOnNonvestedAwardsWeightedAveragePeriodOfRecognition">
    <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_AccumulatedOtherComprehensiveIncomeByComponentTableTextBlock">
    <definition>Schedule reflecting a roll forward of each component of accumulated comprehensive income (loss) on a net of tax basis.</definition>
    <reference>No authoritative reference available.</reference>
  </Element>
</DefinitionAndReference>
