XML 96 R68.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Fair Value of Derivative and Other Financial Instruments, Available for Sale Securities (Details) (USD $) | 12 Months Ended
--- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items] |  |  |
Realized impairment (loss) gain | $ 700,000us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetAvailableforsaleSecurities | $ (600,000)us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetAvailableforsaleSecurities | $ (5,200,000)us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetAvailableforsaleSecurities
PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 250,145,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember | 226,855,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember |
Available-for-sale securities, Unrealized gains | 46,348,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember | 42,602,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember |
Proceeds from sales | 117,989,000us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember | 271,140,000us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember | 167,330,000us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember
Gross realized gains | 15,162,000us-gaap_AvailableForSaleSecuritiesGrossRealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember | 14,308,000us-gaap_AvailableForSaleSecuritiesGrossRealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember | 15,907,000us-gaap_AvailableForSaleSecuritiesGrossRealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember
Gross realized (losses) | (3,964,000)us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses / dei_LegalEntityAxis = pnm_PnmrAndPnmMember | (4,298,000)us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses / dei_LegalEntityAxis = pnm_PnmrAndPnmMember | (8,170,000)us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses / dei_LegalEntityAxis = pnm_PnmrAndPnmMember
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, before Tax, Portion Attributable to Parent | 0us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent / dei_LegalEntityAxis = pnm_PnmrAndPnmMember |  |
Cash and equivalents [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 8,276,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CashAndCashEquivalentsMember | 3,356,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CashAndCashEquivalentsMember |
Available-for-sale securities, Unrealized gains | 0us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CashAndCashEquivalentsMember | 0us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CashAndCashEquivalentsMember |
Domestic value [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 45,340,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticValueMember | 39,460,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticValueMember |
Available-for-sale securities, Unrealized gains | 17,418,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticValueMember | 14,523,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticValueMember |
Domestic growth [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 74,053,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticGrowthMember | 76,292,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticGrowthMember |
Available-for-sale securities, Unrealized gains | 21,354,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticGrowthMember | 25,656,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticGrowthMember |
International and other [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 16,599,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_MultinationalMember | 16,633,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_MultinationalMember |
Available-for-sale securities, Unrealized gains | 156,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_MultinationalMember | 1,040,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_MultinationalMember |
U.S. Government [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 22,563,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember | 21,941,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember |
Available-for-sale securities, Unrealized gains | 903,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember | 158,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember |
Municipals [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 68,973,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MunicipalBondsMember | 58,568,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MunicipalBondsMember |
Available-for-sale securities, Unrealized gains | 5,851,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MunicipalBondsMember | 1,018,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MunicipalBondsMember |
Corporate and other [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 14,341,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_OtherDebtSecuritiesMember | 10,605,000us-gaap_AvailableForSaleSecurities / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_OtherDebtSecuritiesMember |
Available-for-sale securities, Unrealized gains | 666,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_OtherDebtSecuritiesMember | 207,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_OtherDebtSecuritiesMember |
Measured on a recurring basis [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 250,145,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember | 226,855,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember |
Measured on a recurring basis [Member] | Nuclear Decommissioning Trust [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 244,600,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_NuclearDecommissioningTrustMember | 222,500,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_NuclearDecommissioningTrustMember |
Measured on a recurring basis [Member] | Mine Reclamation Trust [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 5,500,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_MineReclamationTrustMember | 4,400,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_MineReclamationTrustMember |
Measured on a recurring basis [Member] | Cash and equivalents [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 8,276,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CashAndCashEquivalentsMember | 3,356,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CashAndCashEquivalentsMember |
Measured on a recurring basis [Member] | Domestic value [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 45,340,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticValueMember | 39,460,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticValueMember |
Measured on a recurring basis [Member] | Domestic growth [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 74,053,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticGrowthMember | 76,292,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_DomesticGrowthMember |
Measured on a recurring basis [Member] | International and other [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 16,599,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_MultinationalMember | 16,633,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = pnm_MultinationalMember |
Measured on a recurring basis [Member] | U.S. Government [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 22,563,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember | 21,941,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember |
Measured on a recurring basis [Member] | Municipals [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | 68,973,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MunicipalBondsMember | 58,568,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MunicipalBondsMember |
Measured on a recurring basis [Member] | Corporate and other [Member] | PNMR and PNM [Member] |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available-for-sale securities, Fair value | $ 14,341,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_OtherDebtSecuritiesMember | $ 10,605,000us-gaap_AvailableForSaleSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / dei_LegalEntityAxis = pnm_PnmrAndPnmMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_OtherDebtSecuritiesMember |

X
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 + Details
Name: | us-gaap_AvailableForSaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossRealizedGains
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount before tax of other than temporary impairment loss (OTTI) on investments in available-for-sale and held-to-maturity debt securities, recognized in other comprehensive loss and attributable to parent entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 34D -URI http://asc.fasb.org/extlink&oid=27723805&loc=SL6284304-111560 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 35 -URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e25362-111560 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetAvailableforsaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26853-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=pnm_DomesticGrowthMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=pnm_DomesticValueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=pnm_MultinationalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_MunicipalBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |