Debt Instrument, Repurchased Amount, Irrevocable Transfer

No definition available.

Name:	flr_DebtInstrumentRepurchasedAmountIrrevocableTransfer
Namespace Prefix:	flr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Repayments of Debt Expected in Next Fiscal Period

+ References

No definition available.

+ Details

Name:	flr_RepaymentsOfDebtExpectedInNextFiscalPeriod
Namespace Prefix:	flr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Price of the entity's common stock which would be required to be attained for the conversion feature embedded in the debt instrument to become effective.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleStockPriceTrigger
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value amount of debt instrument that was repurchased.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentRepurchaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash outflow for short-term and long-term debt. Excludes payment of lease obligation.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentAxis=flr_SeniorNotes35PercentDue15December2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=flr_SeniorNotes1750PercentDue21March2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=flr_SeniorNotes1750PercentDue2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=flr_SeniorNotes350PercentDue2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_GeneralAndAdministrativeExpenseMember
Namespace Prefix:
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Debt and Letters of Credit - Notes Discharge & Redemption of 2024 and 2023 Notes (Details) $ / shares in Units, € in Millions, $ in Millions	1 Months Ended				12 Months Ended
	Dec. 31, 2023 USD ($)	Aug. 31, 2023 USD ($) $ / shares	Jan. 31, 2023 USD ($)	Jan. 31, 2023 EUR (€)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Line of Credit Facility [Line Items]
Repayments of debt					$ 249	$ 41	$ 525
2024 Notes
Line of Credit Facility [Line Items]
Repurchase amount		$ 115
Stock price trigger (in dollar per share) \| $ / shares		$ 975.03
2023 Senior Notes
Line of Credit Facility [Line Items]
Expected debt repayments	$ 266			€ 129
Repayments of debt			$ 140			$ 41
Irrevocable transfer	$ 262
Senior Notes 1.750%, Due 2023
Line of Credit Facility [Line Items]
Debt instrument, face amount							375
Senior Notes 3.50 Percent, Due 2024
Line of Credit Facility [Line Items]
Debt instrument, face amount							108
Senior Notes 1.750 Percent, Due 2023 and Senior Notes 3.50 Percent, Due 2024
Line of Credit Facility [Line Items]
Repayments of debt							26
Senior Notes 1.750 Percent, Due 2023 and Senior Notes 3.50 Percent, Due 2024 \| Corporate general and administrative expense
Line of Credit Facility [Line Items]
Loss on extinguishment of debt							$ 20