Commitments and Contingencies (Details 2) In Millions, unless otherwise specified		3 Months Ended			1 Months Ended	3 Months Ended
	Sep. 30, 2011 USD ($)	Mar. 31, 2012 Monto Coal Pty Limited [Member] AUD	Mar. 31, 2012 Gulf Power Company Litigation [Member] T	Sep. 30, 2010 Gulf Power Company Litigation [Member] USD ($)	Jun. 30, 2005 Oklahoma Lead Litigation [Member] USD ($)	Mar. 31, 2012 Oklahoma Lead Litigation [Member] USD ($) sites leadmills	Dec. 31, 2011 Oklahoma Lead Litigation [Member] USD ($)	Mar. 31, 2012 Prarie State Energy Campus [Member] USD ($)	Dec. 31, 2011 Prarie State Energy Campus [Member] USD ($)	Jan. 19, 2012 Pending or Threatened Litigation [Member] Gulf Power Company Litigation [Member] USD ($)
Loss Contingencies [Line Items]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures								$ 241.7	$ 238.7
Loss Contingency [Abstract]
Litigation Settlement Damages Awarded to Plaintiff	20.5			0
Litigation Settlement, Prejudgement Interest										6.9
Damages sought for alleged past and future tonnage shortfalls			5,000,000
Number of lead mills formerly operated by predecessor of subsidiary						2
Percentage of total amount of crude ore mined in Picher, Oklahoma						0.15%
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)						5
Number of additional national priority list sites in which claims were asserted						13
Total number of national priority list sites						18
Reduced number of national priority list sites due to completion of work, transfer or regulatory inactivity						11
Undiscounted environmental clean-up liabilities, total						48.9	52.5
Undiscounted environmental clean-up liabilities, current						8.1	11.6
Alleged residential yard remediation costs incurred by the EPA due to potentially responsible parties' activities					125
Ownership Percentage In Subsidiaries		51.00%
Loss Contingency, Damages Sought, Value		1,193.2