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Commitments, Guarantees and Contingencies - Coal, Rail and Shipping Contracts (Details) (USD $) In Millions, unless otherwise specified | Mar. 31, 2012
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Coal, Rail and Shipping Contracts [Line Items] |
Coal Contracts, Expiration Date | 2013
Transportation Contracts, Expiration Date | 2015
Coal and Transportation [Member] |
Coal, Rail and Shipping Contracts [Line Items] |
Minimum Annual Payment Obligation, Current Year | 37.4
Minimum Annual Payment Obligation, Year Two | 23.8

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- Definition The aggregate amount of payments due in the second year after the balance sheet date to reduce a recorded unconditional purchase obligation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 47 -Paragraph 10 -Subparagraph b -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25383-109308 + Details
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- Definition The aggregate amount of payments due in the first year after the balance sheet date to reduce a recorded unconditional purchase obligation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 47 -Paragraph 10 -Subparagraph b -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25383-109308 + Details
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