XML 92 R58.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Commitments and Contingencies - Coal Supply (Details) (USD $) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |
Other current assets | $ 65,264,000 us-gaap_OtherAssetsCurrent | $ 58,471,000 us-gaap_OtherAssetsCurrent |  |
Public Service Company of New Mexico [Member] | Surface [Member] |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |
Regulatory Assets | 100,000,000 us-gaap_RegulatoryAssets / pnm_ClassificationOfMineAxis = pnm_SurfaceMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember |  |  |
Public Service Company of New Mexico [Member] | Loss on Long-term Purchase Commitment [Member] | Surface [Member] |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |
Loss Contingency Accrual | 25,600,000 us-gaap_LossContingencyAccrualAtCarryingValue / pnm_ClassificationOfMineAxis = pnm_SurfaceMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember / us-gaap_LossContingenciesByNatureOfContingencyAxis = us-gaap_LossOnLongTermPurchaseCommitmentMember | 25,700,000 us-gaap_LossContingencyAccrualAtCarryingValue / pnm_ClassificationOfMineAxis = pnm_SurfaceMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember / us-gaap_LossContingenciesByNatureOfContingencyAxis = us-gaap_LossOnLongTermPurchaseCommitmentMember |  |
Final Reclamation, capped amount to be collected | 100,000,000 pnm_FinalReclamationCappedAmountToBeCollected / pnm_ClassificationOfMineAxis = pnm_SurfaceMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember / us-gaap_LossContingenciesByNatureOfContingencyAxis = us-gaap_LossOnLongTermPurchaseCommitmentMember |  |  |
Public Service Company of New Mexico [Member] | Loss on Long-term Purchase Commitment [Member] | Underground [Member] |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |
Loss Contingency Accrual | 8,800,000 us-gaap_LossContingencyAccrualAtCarryingValue / pnm_ClassificationOfMineAxis = pnm_UndergroundMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember / us-gaap_LossContingenciesByNatureOfContingencyAxis = us-gaap_LossOnLongTermPurchaseCommitmentMember | 8,600,000 us-gaap_LossContingencyAccrualAtCarryingValue / pnm_ClassificationOfMineAxis = pnm_UndergroundMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember / us-gaap_LossContingenciesByNatureOfContingencyAxis = us-gaap_LossOnLongTermPurchaseCommitmentMember |  |
Public Service Company of New Mexico [Member] | Loss on Long-term Purchase Commitment [Member] |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |
Public Utilities, Annual Funding |  | 1,000,000 pnm_PublicUtilitiesAnnualFunding / pnm_CommitmentsAndContingenciesRelatedToEnvironmentAndOtherNatureAxis = us-gaap_LossOnLongTermPurchaseCommitmentMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 300,000 pnm_PublicUtilitiesAnnualFunding / pnm_CommitmentsAndContingenciesRelatedToEnvironmentAndOtherNatureAxis = us-gaap_LossOnLongTermPurchaseCommitmentMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 3,500,000 pnm_PublicUtilitiesAnnualFunding / pnm_CommitmentsAndContingenciesRelatedToEnvironmentAndOtherNatureAxis = us-gaap_LossOnLongTermPurchaseCommitmentMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Public Utilities, Expected Funding Annual Requirements | 600,000 pnm_PublicUtilitiesExpectedFundingAnnualRequirements / pnm_CommitmentsAndContingenciesRelatedToEnvironmentAndOtherNatureAxis = us-gaap_LossOnLongTermPurchaseCommitmentMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember |  |  |
San Juan Generating Station [Member] | Public Service Company of New Mexico [Member] | Loss on Long-term Purchase Commitment [Member] | Surface [Member] |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |
Loss Contingency, Estimate of Possible Loss | 57,000,000 us-gaap_LossContingencyEstimateOfPossibleLoss / pnm_ClassificationOfMineAxis = pnm_SurfaceMember / us-gaap_JointlyOwnedUtilityPlantAxis = pnm_SanJuanGeneratingStationMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember / us-gaap_LossContingenciesByNatureOfContingencyAxis = us-gaap_LossOnLongTermPurchaseCommitmentMember |  |  |
San Juan Generating Station [Member] | Public Service Company of New Mexico [Member] | Loss on Long-term Purchase Commitment [Member] | Underground [Member] |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |
Loss Contingency, Estimate of Possible Loss | 93,300,000 us-gaap_LossContingencyEstimateOfPossibleLoss / pnm_ClassificationOfMineAxis = pnm_UndergroundMember / us-gaap_JointlyOwnedUtilityPlantAxis = pnm_SanJuanGeneratingStationMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember / us-gaap_LossContingenciesByNatureOfContingencyAxis = us-gaap_LossOnLongTermPurchaseCommitmentMember |  |  |
San Juan Generating Station [Member] | Coal Supply [Member] | Public Service Company of New Mexico [Member] |  |  |  |
Public Utilities, Commitments And Contingencies [Line Items] |  |  |  |
Other current assets | $ 38,900,000 us-gaap_OtherAssetsCurrent / us-gaap_JointlyOwnedUtilityPlantAxis = pnm_SanJuanGeneratingStationMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember / us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis = pnm_CoalSupplyMember | $ 37,300,000 us-gaap_OtherAssetsCurrent / us-gaap_JointlyOwnedUtilityPlantAxis = pnm_SanJuanGeneratingStationMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember / us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis = pnm_CoalSupplyMember |  |
Public Utilities, Estimated Increase in Coal Cost, Percentage | 30.00%pnm_PublicUtilitiesEstimatedIncreaseinCoalCostPercentage / us-gaap_JointlyOwnedUtilityPlantAxis = pnm_SanJuanGeneratingStationMember / dei_LegalEntityAxis = pnm_PublicServiceCompanyOfNewMexicoMember / us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis = pnm_CoalSupplyMember |  |  |

X
- Definition Final Reclamation, capped amount to be collected + References No definition available. + Details
Name: | pnm_FinalReclamationCappedAmountToBeCollected
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Public Utilities, Annual Funding + References No definition available. + Details
Name: | pnm_PublicUtilitiesAnnualFunding
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | pnm_PublicUtilitiesCommitmentsAndContingenciesLineItems
Namespace Prefix: | pnm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Estimated Increase in Coal Cost, Percentage + References No definition available. + Details
Name: | pnm_PublicUtilitiesEstimatedIncreaseinCoalCostPercentage
Namespace Prefix: | pnm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Expected Funding Annual Requirements + References No definition available. + Details
Name: | pnm_PublicUtilitiesExpectedFundingAnnualRequirements
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of loss contingency liability. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349 + Details
Name: | us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Reflects the estimated amount of loss from the specified contingency as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349 + Details
Name: | us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Aggregate carrying amount, as of the balance sheet date, of current assets not separately disclosed in the balance sheet. Current assets are expected to be realized or consumed within one year (or the normal operating cycle, if longer). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.8) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 8 -Article 5 + Details
Name: | us-gaap_OtherAssetsCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 + Details
Name: | us-gaap_RegulatoryAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=pnm_PublicServiceCompanyOfNewMexicoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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