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Supplemental Disclosures about Oil and Natural Gas Producing Properties (unaudited) (Details 2) (USD $) In Millions, unless otherwise specified | 12 Months Ended |
--- | --- | ---
Jun. 30, 2012 Boe | Jun. 30, 2011 Boe | Jun. 30, 2010 Boe | Jun. 30, 2009 Boe
Estimated Net Quantities of Proved Oil and Natural Gas Reserves |  |  |  |
Period on the basis of which reserve volumes and values are determined | 12 months |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Balance at the beginning of the period (in Bbls/Mcf/BOE) | 13,847,462 | 12,418,256 | 3,060,040 |
Revisions of previous estimates (in Bbls/Mcf/BOE) | (344,440) | 1,937,405 | (60,943) |
Improved recovery, extensions and discoveries (in Bbls/Mcf/BOE) | 146,249 | 129,926 | 9,544,674 |
Sales of minerals in place (in Bbls/Mcf/BOE) | 0 | (521,688) |  |
Production (sales volumes) (in Bbls/Mcf/BOE) | (208,155) | (116,437) | (125,515) |
Balance at the end of the period (in Bbls/Mcf/BOE) | 13,441,116 | 13,847,462 | 12,418,256 |
Proved developed reserves (in BOE) | 8,032,809 | 5,344,471 | 1,119,498 | 430,441
Increase (decrease) in proved reserves (in BOE) | (400,000) | 1,400,000 | 9,400,000 |
Giddings Field |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Revisions of previous estimates (in Bbls/Mcf/BOE) | (369) |  |  |
Sales of minerals in place (in Bbls/Mcf/BOE) |  | (521,688) |  |
Delhi Field |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Revisions of previous estimates (in Bbls/Mcf/BOE) | 210 |  |  |
Development capital spent by the operator since project inception |  |  | 300 |
Giddings Field and Oklahoma |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Extensions (in BOE) |  |  | 127,905 |
Lopez Field |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Number of well locations transferred | 4 |  |  |
Woodford properties in Oklahoma |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Revisions of previous estimates (in Bbls/Mcf/BOE) | (127) |  |  |
Giddings Field in South Texas |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Improved recovery, extensions and discoveries (in Bbls/Mcf/BOE) | 146 |  |  |
Crude Oil |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Balance at the beginning of the period (in Bbls/Mcf/BOE) | 11,567,846 | 10,254,470 | 945,948 |
Revisions of previous estimates (in Bbls/Mcf/BOE) | 84,219 | 1,475,918 | (113,487) |
Improved recovery, extensions and discoveries (in Bbls/Mcf/BOE) | 137,634 |  | 9,451,758 |
Sales of minerals in place (in Bbls/Mcf/BOE) | 0 | (104,577) |  |
Production (sales volumes) (in Bbls/Mcf/BOE) | (151,081) | (57,965) | (29,749) |
Balance at the end of the period (in Bbls/Mcf/BOE) | 11,638,618 | 11,567,846 | 10,254,470 |
Proved developed reserves (in Bbls/Mcf) | 7,670,934 | 4,986,337 | 706,053 | 104,731
Period of acceleration in projected reversion date of working interest resulting in upward revision of proved oil reserves | 2 years |  |  |
Working interest in proved oil reserves (as a percent) | 24.00% |  |  |
Crude Oil | Delhi Field |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Improved recovery of proved oil reserves (in Bbls) |  |  | 9,411,841 |
Natural Gas Liquids |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Balance at the beginning of the period (in Bbls/Mcf/BOE) | 712,300 | 1,036,627 | 1,054,294 |
Revisions of previous estimates (in Bbls/Mcf/BOE) | (212,677) | (84,154) | (19,147) |
Improved recovery, extensions and discoveries (in Bbls/Mcf/BOE) | 5,461 |  | 29,300 |
Sales of minerals in place (in Bbls/Mcf/BOE) | 0 | (221,469) |  |
Production (sales volumes) (in Bbls/Mcf/BOE) | (12,611) | (18,704) | (27,820) |
Balance at the end of the period (in Bbls/Mcf/BOE) | 492,473 | 712,300 | 1,036,627 |
Proved developed reserves (in Bbls/Mcf) | 111,978 | 100,900 | 157,302 | 141,372
Natural Gas |  |  |  |
Estimated quantities of proved oil and natural gas reserves and changes in quantities of proved developed and undeveloped reserves |  |  |  |
Balance at the beginning of the period (in Bbls/Mcf/BOE) | 9,403,899 | 6,762,954 | 6,358,788 |
Revisions of previous estimates (in Bbls/Mcf/BOE) | (1,295,893) | 3,273,846 | 430,145 |
Improved recovery, extensions and discoveries (in Bbls/Mcf/BOE) | 18,925 | 779,556 | 381,695 |
Sales of minerals in place (in Bbls/Mcf/BOE) | 0 | (1,173,850) |  |
Production (sales volumes) (in Bbls/Mcf/BOE) | (266,775) | (238,607) | (407,674) |
Balance at the end of the period (in Bbls/Mcf/BOE) | 7,860,156 | 9,403,899 | 6,762,954 |
Proved developed reserves (in Bbls/Mcf) | 1,499,382 | 1,543,401 | 1,536,858 | 1,106,028

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- Definition Additions to proved reserves that result from (1) extension of the proved acreage of previously discovered (old) reservoirs through additional drilling in periods after discovery and (2) discovery of new fields with proved reserves or of new reservoirs of proved reserves in old fields. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61831-109447 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 19 -Paragraph 59F -Subparagraph d -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. + Details
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- Definition The net quantity of proved reserves as of the balance sheet date. Proved oil reserves are the estimated quantities of crude oil and natural gas liquids which geological and engineering data demonstrate with reasonable certainty to be recoverable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 10 -Paragraph a -Subparagraph 2 -Article 4 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61831-109447 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-10.(a)(2)) -URI http://asc.fasb.org/extlink&oid=21918352&loc=d3e511914-122862 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 19 -Paragraph 59F -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. + Details
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