XML 138 R107.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Commitments and Contingencies - Tax Assessment (Details) - Four Corners [Member] - NMTRD Coal Severance Tax [Member] - USD ($) $ in Millions | Mar. 31, 2016 | May 23, 2013
--- | --- | ---
Public Utilities, General Disclosures [Line Items] |  |
Assessed coal severance surtax penalty and interest |  | $ 30.0
Payment of settlement | $ 0.1 |

X
- Definition Public Utilities, Assessed Coal Severance Surtax Penalty and Interest + References No definition available. + Details
Name: | pnm_PublicUtilitiesAssessedCoalSeveranceSurtaxPenaltyandInterest
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Public Utilities, Assessed Coal Severance Surtax Penalty and Interest, PNM Share + References No definition available. + Details
Name: | pnm_PublicUtilitiesAssessedCoalSeveranceSurtaxPenaltyandInterestPNMShare
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesGeneralDisclosuresLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_JointlyOwnedUtilityPlantAxis=pnm_FourCornersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_OtherCommitmentsAxis=pnm_NMTRDCoalSeveranceTaxMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |