Public Utilities, Current Surface Mining Royalty Rate applied between 2000 and 2003

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- Definition

Public Utilities, Estimated Underpaid Surface Mining Royalties under proposed rate change

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Public Utilities, PNM Share Estimated Underpaid Surface Mining Royalties under proposed rate change

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- Definition

Public Utilities, Proposed Retroactive Surface Mining Royalty Rate

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Commitments and Contingencies - Mining Royalty Rate (Details) - Continuous Highwall Mining [Member] - San Juan Generating Station [Member] - USD ($) $ in Millions	Aug. 31, 2013	Aug. 31, 2006	Dec. 31, 2003
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%