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Commitments and Contingencies - Mining Royalty Rate (Details) - Continuous Highwall Mining - San Juan Generating Station - USD ($) $ in Millions | Aug. 31, 2013 | Aug. 31, 2006 | Dec. 31, 2003
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Public Utilities, General Disclosures [Line Items] |  |  |
Proposed retroactive surface mining royalty rate | 12.50% |  |
Surface mining royalty rate applied between 2000 and 2003 |  |  | 8.00%
Estimated underpaid surface mining royalties under proposed rate change |  | $ 5 |
PNM's share of estimated underpaid surface mining royalties under proposed rate change |  | 46.30% |

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- Definition Public Utilities, PNM Share Estimated Underpaid Surface Mining Royalties under proposed rate change + References No definition available. + Details
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- Details
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- Details
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