Commitments and Contingencies (Details 2) AUD in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2015 AUD mW sites	Sep. 30, 2015 USD ($) mW sites	Sep. 30, 2014 AUD	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Prarie State Energy Campus [Member]
Loss Contingency [Abstract]
Capacity of new electricity generation project | mW		1,600	1,600
Undivided interest percent of new electricity generation project	5.06%		5.06%
Monto Coal Pty Limited [Member]
Loss Contingency [Abstract]
Ownership percentage in subsidiaries	51.00%		51.00%
Loss Contingency Damages Sought Minimum | AUD		AUD 15.6
Loss Contingency Damages Sought Value Max | AUD		1,800.0
Eagle Mining [Member]
Loss Contingency [Abstract]
Additional charge recorded as a result of the damages awarded to Eagle in arbitration					$ 15.6
Loss Contingency Accrual					$ 23.4
Gain Related to Litigation Settlement	$ 10.8		$ 10.8
Wilkie Creek [Member]
Loss Contingency [Abstract]
Damages sought | AUD				AUD 113.1
Potential Annual Payments Awarded | AUD		AUD 11.8
Charge to discontinued operations			7.6
Litigation reserve, amount	7.6		$ 7.6
Oklahoma Lead Litigation [Member]
Loss Contingency [Abstract]
Number of national priority list sites based on the Superfund Amendments and Reauthorization Act of 1986 at which Gold Fields or the former affiliate, has been named a potentially responsible party (PRP) | sites		5	5
Number of additional national priority list sites in which CERCLA claims were asserted | sites		13	13
Total number of national priority list sites | sites		18	18
Reduced number of national priority list sites due to completion of work, transfer or regulatory inactivity | sites		6	6
Undiscounted environmental clean-up liabilities, total	64.3		$ 64.3			$ 69.4
Undiscounted environmental clean-up liabilities, current	$ 14.4		$ 14.4			$ 19.4