Provision for Post-Retirement Health Care Costs - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
Dec. 31, 2010	Dec. 31, 2011	Jun. 30, 2010
Gold Fields Group (excluding South Deep)
Defined Benefit Plan Disclosure [Line Items]
Contributions to post-retirement health care scheme	$ 0.5	$ 0.2	$ 0.2
Health care cost, assumptions, inflation rate per annum	8.00%	8.00%	8.00%
Health care cost, assumptions, discount rate per annum	8.75%	8.75%	9.00%
Amount a one percentage point increase in assumed health care cost trend rates would have increased the aggregate of service and interest cost	0.01	0.03	0.10
Amount a one percentage point increase in assumed health care cost trend rates would have increased the accumulated post-retirement health care benefit	0.3	0.2	0.2
Amount a one percentage point decrease in assumed health care cost trend rates would have decreased the aggregate of service and interest cost	0.01	0.01	0.01
Amount a one percentage point decrease in assumed health care cost trend rates would have decrease the accumulated post-retirement health care benefit obligation	0.2	0.2	0.2
South Deep Gold Mine
Defined Benefit Plan Disclosure [Line Items]
Contributions to post-retirement health care scheme	$ 0.1	$ 0.1	$ 0.1
Health care cost, assumptions, inflation rate per annum	8.00%	8.00%	8.00%
Health care cost, assumptions, discount rate per annum	8.75%	8.75%	9.00%

The interest rate used to adjust for the time value of money for the plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

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- Definition

Expected rate of compensation increases (for pay-related plans).

+ References

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- Definition

The increase in the fair value of plan assets from contributions made by the employer.

+ References

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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The effect of a one-percentage-point decrease in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

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The effect of a one-percentage- point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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The effect of a one-percentage-point increase in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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The effect of a one-percentage-point increase in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph m

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Name Accounting Standards Codification

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