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Environmental Trust Funds - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Environmental Trust Funds [abstract] |  |
Term deposit | $ 17.6 | $ 16.8
Cash deposit | $ 61.7 | $ 52.7

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- Definition Environmental trust fund. + References No definition available. + Details
Name: | gfi_EnvironmentalTrustFundsAbstract
Namespace Prefix: | gfi_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition The portion of the funds intended to fund environmental rehabilitation obligations of the entity consisting of secured cash deposits. + References No definition available. + Details
Name: | gfi_SecuredCashDepositsEnvironmentalTrustFunds
Namespace Prefix: | gfi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Definition The portion of the funds intended to fund environmental rehabilitation obligations of the entity consisting of term deposits. + References No definition available. + Details
Name: | gfi_TermDepositsEnvironmentalTrustFunds
Namespace Prefix: | gfi_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration