Income Taxes	9 Months Ended
Sep. 30, 2013
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company's tax benefit of $18.6 million and tax expense of $49.3 million for the three months ended September 30, 2013 and 2012, respectively, include remeasurement benefit of $2.6 million and remeasurement expense of $13.6 million related to foreign tax accounts, respectively. The Company's tax benefit of $199.6 million and tax expense of $85.5 million for the nine months ended September 30, 2013 and 2012, respectively, include remeasurement benefit of $38.1 million and remeasurement expense of $8.7 million related to foreign tax accounts, respectively. The 2013 effective tax rate before remeasurement is based on the Company's estimated full year effective tax rate made up of the expected statutory tax expense more than offset by reductions from percentage depletion, foreign rate differential and Australian minerals resource rent tax. During the three and nine months ended September 30, 2013, the Company decreased its net unrecognized tax benefits, interest and penalties by $66.5 million due to the expiration of statutes of limitations. During the second quarter and included in the nine months ended September 30, 2013, the Company released a portion of its valuation allowance on U.S. capital loss carry forwards amounting to $25.5 million due to a change in expected realization upon sale of non-strategic U.S. coal reserves and surface lands. The Company's Australian income tax returns for the tax years 2004 through 2012 are under examination by the Australian Tax Office (ATO). During the third quarter ended September 30, 2013, the ATO began an income tax audit of the 2010 through 2012 tax years. During 2013, the ATO issued a final notice challenging certain financing transactions with a total assessment of $70.4 million, comprised of additional taxes of $48.9 million plus interest and penalties of $21.5 million. The Company made a $35.2 million advance deposit to the ATO in order for the Company to proceed with negotiation and/or litigation of the disputed tax assessment. That deposit has been reflected in "Other current assets" in the unaudited condensed consolidated balance sheet as of September 30, 2013. The Company believes during the next twelve months it is reasonably possible for a $40 million decrease in its net unrecognized tax benefits due to potential audit settlements. All tax assessment amounts above are presented in U.S. dollars at foreign currency exchange rates in effect at September 30, 2013.

Income Taxes

9 Months Ended

Sep. 30, 2013

The Company's tax benefit of $18.6 million and tax expense of $49.3 million for the three months ended September 30, 2013 and 2012, respectively, include remeasurement benefit of $2.6 million and remeasurement expense of $13.6 million related to foreign tax accounts, respectively. The Company's tax benefit of $199.6 million and tax expense of $85.5 million for the nine months ended September 30, 2013 and 2012, respectively, include remeasurement benefit of $38.1 million and remeasurement expense of $8.7 million related to foreign tax accounts, respectively. The 2013 effective tax rate before remeasurement is based on the Company's estimated full year effective tax rate made up of the expected statutory tax expense more than offset by reductions from percentage depletion, foreign rate differential and Australian minerals resource rent tax. During the three and nine months ended September 30, 2013, the Company decreased its net unrecognized tax benefits, interest and penalties by $66.5 million due to the expiration of statutes of limitations. During the second quarter and included in the nine months ended September 30, 2013, the Company released a portion of its valuation allowance on U.S. capital loss carry forwards amounting to $25.5 million due to a change in expected realization upon sale of non-strategic U.S. coal reserves and surface lands.

The Company's Australian income tax returns for the tax years 2004 through 2012 are under examination by the Australian Tax Office (ATO). During the third quarter ended September 30, 2013, the ATO began an income tax audit of the 2010 through 2012 tax years. During 2013, the ATO issued a final notice challenging certain financing transactions with a total assessment of $70.4 million, comprised of additional taxes of $48.9 million plus interest and penalties of $21.5 million. The Company made a $35.2 million advance deposit to the ATO in order for the Company to proceed with negotiation and/or litigation of the disputed tax assessment. That deposit has been reflected in "Other current assets" in the unaudited condensed consolidated balance sheet as of September 30, 2013. The Company believes during the next twelve months it is reasonably possible for a $40 million decrease in its net unrecognized tax benefits due to potential audit settlements. All tax assessment amounts above are presented in U.S. dollars at foreign currency exchange rates in effect at September 30, 2013.