Commitments and Contingencies	9 Months Ended
Sep. 30, 2011
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments As of September 30, 2011, purchase commitments for capital expenditures were $521.4 million, all of which is obligated within the next five years with $477.6 million obligated in the next 12 months. A subsidiary of the Company owns a 5.06% undivided interest in Prairie State. The Company invested $29.8 million during the nine months ended September 30, 2011, representing its 5.06% share of the construction costs. Included in “Investments and other assets” in the condensed consolidated balance sheets as of September 30, 2011 and December 31, 2010 are costs of $232.3 million and $202.5 million, respectively. The Company’s share of total construction costs for Prairie State is expected to be approximately $250 million with most of the remaining funding expected in 2011. In July 2011, the Company was named the winning bidder for control of approximately 220 million tons of low sulfur coal reserves in the Powder River Basin of Wyoming that will be assigned to the Company’s Caballo Mine. The Company made its first payment of $42.1 million in July 2011, with the remaining annual payments of $42.1 million to be made in July of each of the next four years. The related lease was executed by the U.S. Bureau of Land Management effective November 1, 2011. There were no other material changes to the Company’s commitments from the information provided in Note 20 to the Consolidated Financial Statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2010. Contingencies From time to time, the Company and/or its subsidiaries are involved in legal proceedings arising in the ordinary course of business or related to indemnities or historical operations. The Company believes it has recorded adequate reserves for these liabilities and that there is no individual case pending that is likely to have a material adverse effect on the Company’s financial condition, results of operations or cash flows. The Company discusses its significant legal proceedings below. Litigation Relating to Continuing Operations Navajo Nation Litigation. On June 18, 1999, the Navajo Nation served three of the Company’s subsidiaries, including Peabody Western Coal Company (Peabody Western), with a complaint that had been filed in the U.S. District Court for the District of Columbia which alleged that the defendants jointly participated in unlawful activity to obtain favorable coal lease amendments. The plaintiff sought actual and punitive damages and the termination and reformation of two coal leases. The court allowed the Hopi Tribe to intervene in this lawsuit, and the Hopi Tribe sought unspecified actual and punitive damages and reformation of its coal lease. One of the Company’s subsidiaries named as a defendant is now a subsidiary of Patriot Coal Corporation (Patriot). However, the Company was responsible for this litigation under the Separation Agreement entered into with Patriot in connection with the spin-off. In October 2010, the Company and the other defendants settled the Hopi claims, and the court dismissed those claims. In August 2011, the Company and other defendants settled the Navajo claims, and agreed to dismiss all of the pending litigation with prejudice. In connection with this settlement, the Company recorded a provision totaling $24.5 million in the nine months ended September 30, 2011. The court has dismissed this lawsuit, and this matter has concluded. Gulf Power Company Litigation. On June 22, 2006, Gulf Power Company (Gulf Power) filed a breach of contract lawsuit against a Company subsidiary in the U.S. District Court, Northern District of Florida, contesting the force majeure declaration by the Company’s subsidiary under a coal supply agreement with Gulf Power and seeking damages for alleged past and future tonnage shortfalls of nearly five million tons under the agreement, which expired on December 31, 2007. Gulf Power filed a motion for partial summary judgment on liability, and the Company subsidiary filed a motion for summary judgment seeking complete dismissal. On June 30, 2009, the court granted Gulf Power’s motion for partial summary judgment and denied the Company subsidiary’s motion for summary judgment. The damages portion of the trial was held in February 2010. On September 30, 2010, the court entered its order on damages, awarding Gulf Power zero dollars in damages and the Company its costs to defend the lawsuit. The Company is also seeking its reasonable attorney’s fees incurred since October 15, 2008. On November 1, 2010, Gulf Power filed a motion to alter or amend the judgment, contesting the trial court’s damages order, to which the Company objected. The court entered an order on July 29, 2011, that (1) affirmed its September 30, 2010 decision in all respects except for 2007 cover coal purchases, (2) granted in part Gulf Power’s motion to alter judgment with respect to 2007 cover coal purchases, and (3) scheduled a hearing for August 25, 2011 to consider further evidence on expenses saved by Gulf Power in its 2007 cover coal purchases. On September 30, 2011, the court entered an order awarding Gulf Power damages in the amount of $20.5 million for its 2007 cover purchases. On October 4, 2011, the court ordered Gulf Power to submit within 10 days a calculation of the amount of interest to which it claims it is entitled, and Gulf Power has responded to the order requesting $6.9 million in prejudgment interest. On October 26, 2011, the court entered an order extending the time for filing notices of appeal until November 28, 2011 and referred the matter to a magistrate for a settlement conference prior to that date. The court will defer ruling on prejudgment interest until after the settlement conference. The Company's subsidiary filed a notice of appeal on October 31, 2011. Based on the Company's evaluation of information currently available concerning the issues and their potential impact, the Company believes it will be successful in the liability appeals process and, therefore, no liability has been recorded at this time. Claims and Litigation Relating to Indemnities or Historical Operations Oklahoma Lead Litigation. Gold Fields Mining, LLC (Gold Fields) is a dormant, non-coal producing entity that was previously managed and owned by Hanson PLC, the Company’s predecessor owner. In a February 1997 spin-off, Hanson PLC transferred ownership of Gold Fields to the Company, despite the fact that Gold Fields had no ongoing operations and the Company had no prior involvement in its past operations. Gold Fields is currently one of the Company’s subsidiaries. The Company indemnified TXU Group with respect to certain claims relating to a former affiliate of Gold Fields. A predecessor of Gold Fields formerly operated two lead mills near Picher, Oklahoma prior to the 1950s and mined, in accordance with lease agreements and permits, approximately 0.15% of the total amount of the crude ore mined in the county. Gold Fields and several other companies are defendants in a property damage lawsuit pending in the U.S. District Court for the Northern District of Oklahoma arising from past operations near Picher, Oklahoma. The plaintiffs are seeking compensatory damages for diminution in property values and punitive damages. This case was originally filed as putative class actions, but the court denied class certification and the case was subsequently amended to include a number of individual plaintiffs. Gold Fields was also a defendant in another case alleging property damage and pending in the U.S. District Court for the Northern District of Oklahoma arising out of past operations near Picher, Oklahoma, but the court granted summary judgment in Company's favor in that case. Gold Fields and several other companies are also defendants in a personal injury lawsuit pending in the U.S. District Court for the Northern District of Oklahoma arising from past operations near Picher, Oklahoma. The four plaintiffs are seeking compensatory damages for cognitive impairments allegedly caused by exposure to lead and punitive damages. In June 2005, Gold Fields and other potentially responsible parties (PRPs) received a letter from the U.S. Department of Justice alleging that the potentially responsible parties’ mining operations caused the U.S. Environmental Protection Agency (EPA) to incur approximately $125 million in residential yard remediation costs at Picher, Oklahoma and will cause the EPA to incur additional remediation costs relating to historical mining sites. In June 2008, Gold Fields and other PRPs received letters from the U.S. Department of Justice and the EPA re-initiating settlement negotiations. Gold Fields continues to participate in the settlement discussions. Gold Fields believes it has meritorious defenses to these claims. In February 2005, the state of Oklahoma, on behalf of itself and several other parties, sent a notice to Gold Fields and other companies regarding a possible natural resources damage claim. The state of Oklahoma has also indicated that it seeks to recover remediation costs from these parties. The outcome of litigation and these claims are subject to numerous uncertainties. Based on the Company’s evaluation of the issues and their potential impact, the amount of any future loss cannot be reasonably estimated. However, based on current information, the Company believes these claims are likely to be resolved without a material adverse effect on its financial condition, results of operations or cash flows. Environmental Claims and Litigation Environmental claims have been asserted against Gold Fields related to activities of Gold Fields or a former affiliate. Gold Fields or the former affiliate has been named a potentially responsible party (PRP) at five national priority list sites based on the Superfund Amendments and Reauthorization Act of 1986. Claims were asserted at 13 additional sites, bringing the total to 18, which have since been reduced to 11 by completion of work, transfer or regulatory inactivity. The number of PRP sites in and of itself is not a relevant measure of liability because the nature and extent of environmental concerns varies by site, as does the estimated share of responsibility for Gold Fields or the former affiliate. Undiscounted liabilities for environmental cleanup-related costs for all of the sites noted above were $53.4 million as of September 30, 2011 and $51.1 million as of December 31, 2010, $9.6 million and $6.3 million of which was reflected as a current liability, respectively. These amounts represent those costs that the Company believes are probable and reasonably estimable. Gold Fields is involved in other litigation and claims in the Picher area, and the Company indemnified TXU Group with respect to a defendant as is more fully discussed under the “Oklahoma Lead Litigation” caption above. Significant uncertainty exists as to whether claims will be pursued against Gold Fields in all cases, and where they are pursued, the amount of the eventual costs and liabilities, which could be greater or less than the liabilities recorded in the consolidated balance sheets. Based on the Company’s evaluation of the issues and their potential impact, the total amount of any future loss cannot be reasonably estimated. However, based on current information, the Company believes these claims and litigation are likely to be resolved without a material adverse effect on its financial condition, results of operations or cash flows. Native Village of Kivalina and City of Kivalina v. ExxonMobil Corporation, et al. In February 2008, the Native Village of Kivalina and the City of Kivalina filed a lawsuit in the U.S. District Court for the Northern District of California against the Company, several owners of electricity generating facilities and several oil companies. The plaintiffs are the governing bodies of a village in Alaska that they contend is being destroyed by erosion allegedly caused by global warming that the plaintiffs attribute to emissions of greenhouse gases by the defendants. The plaintiffs assert claims for nuisance, and allege that the defendants have acted in concert and are jointly and severally liable for the plaintiffs’ damages. The suit seeks damages for lost property values and for the cost of relocating the village. The defendants filed motions to dismiss on the grounds of lack of personal and subject matter jurisdiction. In June 2009, the court granted defendants’ motion to dismiss for lack of subject matter jurisdiction finding that plaintiffs’ federal claim for nuisance is barred by the political question doctrine and for lack of standing. The plaintiffs are appealing the court’s dismissal to the U.S. Court of Appeals for the Ninth Circuit. The parties have filed their respective briefs with the court. The Ninth Circuit stayed the case until July 15, 2011, pending a decision by the U.S. Supreme Court in American Electric Power Co. (AEP) v. Connecticut. On June 20, 2011, the U.S. Supreme Court reversed and remanded the decision by the Second Circuit in AEP v. Connecticut, in which the Court unanimously held that plaintiffs’ federal common law public nuisance claim, which sought abatement of the utility company defendants’ carbon dioxide emissions from power plants, is displaced by the Clean Air Act, 42 U.S.C. § 7401, et. seq. The Kivalina parties have requested the Ninth Circuit to enter a briefing schedule to supplement the parties’ briefs based on the AEP decision. Other In addition, at times the Company becomes a party to other claims, lawsuits, arbitration proceedings and administrative procedures in the ordinary course of business in the U.S., Australia and other countries where the Company does business. In June 2007, the New York Office of the Attorney General served a letter and subpoena on the Company, seeking information and documents relating to the Company’s disclosure to investors of risks associated with possible climate change and related legislation and regulations. The Company believes that it has made full and proper disclosure of these potential risks. Based on current information, the Company believes that the ultimate resolution of such other pending or threatened proceedings is not reasonably likely to have a material adverse effect on its financial position, results of operations or liquidity.

Commitments and Contingencies

Commitments

As of September 30, 2011, purchase commitments for capital expenditures were $521.4 million, all of which is obligated within the next five years with $477.6 million obligated in the next 12 months.

A subsidiary of the Company owns a 5.06% undivided interest in Prairie State. The Company invested $29.8 million during the nine months ended September 30, 2011, representing its 5.06% share of the construction costs. Included in “Investments and other assets” in the condensed consolidated balance sheets as of September 30, 2011 and December 31, 2010 are costs of $232.3 million and $202.5 million, respectively. The Company’s share of total construction costs for Prairie State is expected to be approximately $250 million with most of the remaining funding expected in 2011.

In July 2011, the Company was named the winning bidder for control of approximately 220 million tons of low sulfur coal reserves in the Powder River Basin of Wyoming that will be assigned to the Company’s Caballo Mine. The Company made its first payment of $42.1 million in July 2011, with the remaining annual payments of $42.1 million to be made in July of each of the next four years. The related lease was executed by the U.S. Bureau of Land Management effective November 1, 2011.

There were no other material changes to the Company’s commitments from the information provided in Note 20 to the Consolidated Financial Statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2010.

Contingencies

From time to time, the Company and/or its subsidiaries are involved in legal proceedings arising in the ordinary course of business or related to indemnities or historical operations. The Company believes it has recorded adequate reserves for these liabilities and that there is no individual case pending that is likely to have a material adverse effect on the Company’s financial condition, results of operations or cash flows. The Company discusses its significant legal proceedings below.

Litigation Relating to Continuing Operations

Navajo Nation Litigation. On June 18, 1999, the Navajo Nation served three of the Company’s subsidiaries, including Peabody Western Coal Company (Peabody Western), with a complaint that had been filed in the U.S. District Court for the District of Columbia which alleged that the defendants jointly participated in unlawful activity to obtain favorable coal lease amendments. The plaintiff sought actual and punitive damages and the termination and reformation of two coal leases. The court allowed the Hopi Tribe to intervene in this lawsuit, and the Hopi Tribe sought unspecified actual and punitive damages and reformation of its coal lease. One of the Company’s subsidiaries named as a defendant is now a subsidiary of Patriot Coal Corporation (Patriot). However, the Company was responsible for this litigation under the Separation Agreement entered into with Patriot in connection with the spin-off.

In October 2010, the Company and the other defendants settled the Hopi claims, and the court dismissed those claims. In August 2011, the Company and other defendants settled the Navajo claims, and agreed to dismiss all of the pending litigation with prejudice. In connection with this settlement, the Company recorded a provision totaling $24.5 million in the nine months ended September 30, 2011. The court has dismissed this lawsuit, and this matter has concluded.

Gulf Power Company Litigation. On June 22, 2006, Gulf Power Company (Gulf Power) filed a breach of contract lawsuit against a Company subsidiary in the U.S. District Court, Northern District of Florida, contesting the force majeure declaration by the Company’s subsidiary under a coal supply agreement with Gulf Power and seeking damages for alleged past and future tonnage shortfalls of nearly five million tons under the agreement, which expired on December 31, 2007. Gulf Power filed a motion for partial summary judgment on liability, and the Company subsidiary filed a motion for summary judgment seeking complete dismissal. On June 30, 2009, the court granted Gulf Power’s motion for partial summary judgment and denied the Company subsidiary’s motion for summary judgment. The damages portion of the trial was held in February 2010. On September 30, 2010, the court entered its order on damages, awarding Gulf Power zero dollars in damages and the Company its costs to defend the lawsuit. The Company is also seeking its reasonable attorney’s fees incurred since October 15, 2008. On November 1, 2010, Gulf Power filed a motion to alter or amend the judgment, contesting the trial court’s damages order, to which the Company objected. The court entered an order on July 29, 2011, that (1) affirmed its September 30, 2010 decision in all respects except for 2007 cover coal purchases, (2) granted in part Gulf Power’s motion to alter judgment with respect to 2007 cover coal purchases, and (3) scheduled a hearing for August 25, 2011 to consider further evidence on expenses saved by Gulf Power in its 2007 cover coal purchases. On September 30, 2011, the court entered an order awarding Gulf Power damages in the amount of $20.5 million for its 2007 cover purchases. On October 4, 2011, the court ordered Gulf Power to submit within 10 days a calculation of the amount of interest to which it claims it is entitled, and Gulf Power has responded to the order requesting $6.9 million in prejudgment interest. On October 26, 2011, the court entered an order extending the time for filing notices of appeal until November 28, 2011 and referred the matter to a magistrate for a settlement conference prior to that date. The court will defer ruling on prejudgment interest until after the settlement conference. The Company's subsidiary filed a notice of appeal on October 31, 2011. Based on the Company's evaluation of information currently available concerning the issues and their potential impact, the Company believes it will be successful in the liability appeals process and, therefore, no liability has been recorded at this time.

Claims and Litigation Relating to Indemnities or Historical Operations

Oklahoma Lead Litigation. Gold Fields Mining, LLC (Gold Fields) is a dormant, non-coal producing entity that was previously managed and owned by Hanson PLC, the Company’s predecessor owner. In a February 1997 spin-off, Hanson PLC transferred ownership of Gold Fields to the Company, despite the fact that Gold Fields had no ongoing operations and the Company had no prior involvement in its past operations. Gold Fields is currently one of the Company’s subsidiaries. The Company indemnified TXU Group with respect to certain claims relating to a former affiliate of Gold Fields. A predecessor of Gold Fields formerly operated two lead mills near Picher, Oklahoma prior to the 1950s and mined, in accordance with lease agreements and permits, approximately 0.15% of the total amount of the crude ore mined in the county.

Gold Fields and several other companies are defendants in a property damage lawsuit pending in the U.S. District Court for the Northern District of Oklahoma arising from past operations near Picher, Oklahoma. The plaintiffs are seeking compensatory damages for diminution in property values and punitive damages. This case was originally filed as putative class actions, but the court denied class certification and the case was subsequently amended to include a number of individual plaintiffs. Gold Fields was also a defendant in another case alleging property damage and pending in the U.S. District Court for the Northern District of Oklahoma arising out of past operations near Picher, Oklahoma, but the court granted summary judgment in Company's favor in that case.

Gold Fields and several other companies are also defendants in a personal injury lawsuit pending in the U.S. District Court for the Northern District of Oklahoma arising from past operations near Picher, Oklahoma. The four plaintiffs are seeking compensatory damages for cognitive impairments allegedly caused by exposure to lead and punitive damages.

In June 2005, Gold Fields and other potentially responsible parties (PRPs) received a letter from the U.S. Department of Justice alleging that the potentially responsible parties’ mining operations caused the U.S. Environmental Protection Agency (EPA) to incur approximately $125 million in residential yard remediation costs at Picher, Oklahoma and will cause the EPA to incur additional remediation costs relating to historical mining sites. In June 2008, Gold Fields and other PRPs received letters from the U.S. Department of Justice and the EPA re-initiating settlement negotiations. Gold Fields continues to participate in the settlement discussions. Gold Fields believes it has meritorious defenses to these claims.

In February 2005, the state of Oklahoma, on behalf of itself and several other parties, sent a notice to Gold Fields and other companies regarding a possible natural resources damage claim. The state of Oklahoma has also indicated that it seeks to recover remediation costs from these parties.

The outcome of litigation and these claims are subject to numerous uncertainties. Based on the Company’s evaluation of the issues and their potential impact, the amount of any future loss cannot be reasonably estimated. However, based on current information, the Company believes these claims are likely to be resolved without a material adverse effect on its financial condition, results of operations or cash flows.

Environmental Claims and Litigation

Environmental claims have been asserted against Gold Fields related to activities of Gold Fields or a former affiliate. Gold Fields or the former affiliate has been named a potentially responsible party (PRP) at five national priority list sites based on the Superfund Amendments and Reauthorization Act of 1986. Claims were asserted at 13 additional sites, bringing the total to 18, which have since been reduced to 11 by completion of work, transfer or regulatory inactivity. The number of PRP sites in and of itself is not a relevant measure of liability because the nature and extent of environmental concerns varies by site, as does the estimated share of responsibility for Gold Fields or the former affiliate. Undiscounted liabilities for environmental cleanup-related costs for all of the sites noted above were $53.4 million as of September 30, 2011 and $51.1 million as of December 31, 2010, $9.6 million and $6.3 million of which was reflected as a current liability, respectively. These amounts represent those costs that the Company believes are probable and reasonably estimable.

Gold Fields is involved in other litigation and claims in the Picher area, and the Company indemnified TXU Group with respect to a defendant as is more fully discussed under the “Oklahoma Lead Litigation” caption above.

Significant uncertainty exists as to whether claims will be pursued against Gold Fields in all cases, and where they are pursued, the amount of the eventual costs and liabilities, which could be greater or less than the liabilities recorded in the consolidated balance sheets. Based on the Company’s evaluation of the issues and their potential impact, the total amount of any future loss cannot be reasonably estimated. However, based on current information, the Company believes these claims and litigation are likely to be resolved without a material adverse effect on its financial condition, results of operations or cash flows.

Native Village of Kivalina and City of Kivalina v. ExxonMobil Corporation, et al. In February 2008, the Native Village of Kivalina and the City of Kivalina filed a lawsuit in the U.S. District Court for the Northern District of California against the Company, several owners of electricity generating facilities and several oil companies. The plaintiffs are the governing bodies of a village in Alaska that they contend is being destroyed by erosion allegedly caused by global warming that the plaintiffs attribute to emissions of greenhouse gases by the defendants. The plaintiffs assert claims for nuisance, and allege that the defendants have acted in concert and are jointly and severally liable for the plaintiffs’ damages. The suit seeks damages for lost property values and for the cost of relocating the village. The defendants filed motions to dismiss on the grounds of lack of personal and subject matter jurisdiction. In June 2009, the court granted defendants’ motion to dismiss for lack of subject matter jurisdiction finding that plaintiffs’ federal claim for nuisance is barred by the political question doctrine and for lack of standing. The plaintiffs are appealing the court’s dismissal to the U.S. Court of Appeals for the Ninth Circuit. The parties have filed their respective briefs with the court. The Ninth Circuit stayed the case until July 15, 2011, pending a decision by the U.S. Supreme Court in American Electric Power Co. (AEP) v. Connecticut. On June 20, 2011, the U.S. Supreme Court reversed and remanded the decision by the Second Circuit in AEP v. Connecticut, in which the Court unanimously held that plaintiffs’ federal common law public nuisance claim, which sought abatement of the utility company defendants’ carbon dioxide emissions from power plants, is displaced by the Clean Air Act, 42 U.S.C. § 7401, et. seq. The Kivalina parties have requested the Ninth Circuit to enter a briefing schedule to supplement the parties’ briefs based on the AEP decision.

Other

In addition, at times the Company becomes a party to other claims, lawsuits, arbitration proceedings and administrative procedures in the ordinary course of business in the U.S., Australia and other countries where the Company does business. In June 2007, the New York Office of the Attorney General served a letter and subpoena on the Company, seeking information and documents relating to the Company’s disclosure to investors of risks associated with possible climate change and related legislation and regulations. The Company believes that it has made full and proper disclosure of these potential risks. Based on current information, the Company believes that the ultimate resolution of such other pending or threatened proceedings is not reasonably likely to have a material adverse effect on its financial position, results of operations or liquidity.