Commitments and Contingencies (Details 2) (USD $) In Millions, unless otherwise specified	9 Months Ended		9 Months Ended		9 Months Ended
	Sep. 30, 2011 Navajo Nation Litigation [Member]	Jun. 18, 1999 Navajo Nation Litigation [Member] coalleases subsidiaries	Sep. 30, 2011 Gulf Power Company Litigation [Member] T	Sep. 30, 2010 Gulf Power Company Litigation [Member]	Sep. 30, 2011 Oklahoma Lead Litigation [Member] sites leadmills plaintiffs	Dec. 31, 2010 Oklahoma Lead Litigation [Member]
Loss Contingency [Abstract]
Number of Subsidiaries Served by Plaintiff		3
Number of coal lease terminations sought by plaintiff		2
Alleged shortage of past and future coal shipments under a coal supply agreement, tons			5,000,000
Litigation Settlement Damages Awarded to Plaintiff				$ 0
Litigation Settlement, Damages Awarded			20.5
Litigation Settlement, Prejudgement Interest			6.9
Settlement of Navajo claims	24.5
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					53.4	51.1
Undiscounted environmental clean-up liabilities, current					9.6	6.3
Alleged residential yard remediation costs incurred by the EPA due to potentially responsible parties' activities					$ 125
Number of plaintiffs seeking compensatory damages					4