XML 62 R52.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Segment Information (Details) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2013 | Sep. 30, 2013 | Jun. 30, 2013 | Mar. 31, 2013 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Segment Reporting Information, Profit (Loss) [Abstract] |  |  |  |  |  |  |  |  |  |  |
Electric Operating Revenues | $ 346,845us-gaap_ElectricUtilityRevenue | $ 413,951us-gaap_ElectricUtilityRevenue | $ 346,160us-gaap_ElectricUtilityRevenue | $ 328,897us-gaap_ElectricUtilityRevenue | $ 322,929us-gaap_ElectricUtilityRevenue | $ 399,730us-gaap_ElectricUtilityRevenue | $ 347,599us-gaap_ElectricUtilityRevenue | $ 317,665us-gaap_ElectricUtilityRevenue | $ 1,435,853us-gaap_ElectricUtilityRevenue | $ 1,387,923us-gaap_ElectricUtilityRevenue | $ 1,342,403us-gaap_ElectricUtilityRevenue
Cost of energy |  |  |  |  |  |  |  |  | 471,556us-gaap_CostOfGoodsSoldElectric | 432,316us-gaap_CostOfGoodsSoldElectric | 399,850us-gaap_CostOfGoodsSoldElectric
Margin |  |  |  |  |  |  |  |  | 964,297pnm_GrossMargin | 955,607pnm_GrossMargin | 942,553pnm_GrossMargin
Other operating expenses |  |  |  |  |  |  |  |  | 491,966pnm_OtherOperatingExpenses | 501,884pnm_OtherOperatingExpenses | 504,659pnm_OtherOperatingExpenses
Depreciation and amortization |  |  |  |  |  |  |  |  | 172,634us-gaap_CostOfServicesDepreciationAndAmortization | 166,881us-gaap_CostOfServicesDepreciationAndAmortization | 164,173us-gaap_CostOfServicesDepreciationAndAmortization
Operating income | 62,849us-gaap_OperatingIncomeLoss | 116,799us-gaap_OperatingIncomeLoss | 71,296us-gaap_OperatingIncomeLoss | 48,753us-gaap_OperatingIncomeLoss | 40,532us-gaap_OperatingIncomeLoss | 117,739us-gaap_OperatingIncomeLoss | 77,867us-gaap_OperatingIncomeLoss | 50,704us-gaap_OperatingIncomeLoss | 299,697us-gaap_OperatingIncomeLoss | 286,842us-gaap_OperatingIncomeLoss | 273,721us-gaap_OperatingIncomeLoss
Interest income |  |  |  |  |  |  |  |  | 8,483us-gaap_InvestmentIncomeInterest | 10,043us-gaap_InvestmentIncomeInterest | 13,072us-gaap_InvestmentIncomeInterest
Gain on sale of First Choice |  |  |  |  |  |  |  |  | 0pnm_GainOnSaleOfBusinessSegment | 0pnm_GainOnSaleOfBusinessSegment | 1,012pnm_GainOnSaleOfBusinessSegment
Other income (deductions) |  |  |  |  |  |  |  |  | 12,094pnm_OtherIncomeDeductionsExcludingInterest | (368)pnm_OtherIncomeDeductionsExcludingInterest | 8,075pnm_OtherIncomeDeductionsExcludingInterest
Interest charges |  |  |  |  |  |  |  |  | (119,627)us-gaap_InterestExpense | (121,448)us-gaap_InterestExpense | (120,845)us-gaap_InterestExpense
Earnings before Income Taxes |  |  |  |  |  |  |  |  | 200,647us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest | 175,069us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest | 175,035us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Income Taxes |  |  |  |  |  |  |  |  | 69,738us-gaap_IncomeTaxExpenseBenefit | 59,513us-gaap_IncomeTaxExpenseBenefit | 54,910us-gaap_IncomeTaxExpenseBenefit
Net Earnings | 22,111us-gaap_ProfitLoss | 59,486us-gaap_ProfitLoss | 33,181us-gaap_ProfitLoss | 16,131us-gaap_ProfitLoss | 11,397us-gaap_ProfitLoss | 58,814us-gaap_ProfitLoss | 31,383us-gaap_ProfitLoss | 13,962us-gaap_ProfitLoss | 130,909us-gaap_ProfitLoss | 115,556us-gaap_ProfitLoss | 120,125us-gaap_ProfitLoss
Valencia non-controlling interest |  |  |  |  |  |  |  |  | (14,127)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | (14,521)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | (14,050)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest
Preferred Stock Dividend Requirements of Subsidiary |  |  |  |  |  |  |  |  | (528)us-gaap_DividendsPreferredStock | (528)us-gaap_DividendsPreferredStock | (528)us-gaap_DividendsPreferredStock
Segment earnings (loss) attributable to PNMR |  |  |  |  |  |  |  |  | 116,254us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic | 100,507us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic | 105,547us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
Gross property additions |  |  |  |  |  |  |  |  | 460,658us-gaap_PaymentsToAcquireProductiveAssets | 348,039us-gaap_PaymentsToAcquireProductiveAssets | 308,909us-gaap_PaymentsToAcquireProductiveAssets
Total Assets | 5,829,325us-gaap_Assets |  |  |  | 5,500,210us-gaap_Assets |  |  |  | 5,829,325us-gaap_Assets | 5,500,210us-gaap_Assets | 5,372,583us-gaap_Assets
Goodwill | 278,297us-gaap_Goodwill |  |  |  | 278,297us-gaap_Goodwill |  |  |  | 278,297us-gaap_Goodwill | 278,297us-gaap_Goodwill | 278,297us-gaap_Goodwill
PNM [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information, Profit (Loss) [Abstract] |  |  |  |  |  |  |  |  |  |  |
Electric Operating Revenues |  |  |  |  |  |  |  |  | 1,147,914us-gaap_ElectricUtilityRevenue / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 1,116,312us-gaap_ElectricUtilityRevenue / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 1,092,264us-gaap_ElectricUtilityRevenue / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Cost of energy |  |  |  |  |  |  |  |  | 403,626us-gaap_CostOfGoodsSoldElectric / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 374,710us-gaap_CostOfGoodsSoldElectric / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 353,649us-gaap_CostOfGoodsSoldElectric / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Margin |  |  |  |  |  |  |  |  | 744,288pnm_GrossMargin / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 741,602pnm_GrossMargin / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 738,615pnm_GrossMargin / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Other operating expenses |  |  |  |  |  |  |  |  | 422,051pnm_OtherOperatingExpenses / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 428,591pnm_OtherOperatingExpenses / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 435,442pnm_OtherOperatingExpenses / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Depreciation and amortization |  |  |  |  |  |  |  |  | 109,524us-gaap_CostOfServicesDepreciationAndAmortization / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 103,826us-gaap_CostOfServicesDepreciationAndAmortization / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 97,291us-gaap_CostOfServicesDepreciationAndAmortization / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Operating income |  |  |  |  |  |  |  |  | 212,713us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 209,185us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 205,882us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Interest income |  |  |  |  |  |  |  |  | 8,557us-gaap_InvestmentIncomeInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 10,182us-gaap_InvestmentIncomeInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 13,243us-gaap_InvestmentIncomeInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Gain on sale of First Choice |  |  |  |  |  |  |  |  |  |  | 0pnm_GainOnSaleOfBusinessSegment / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Other income (deductions) |  |  |  |  |  |  |  |  | 12,258pnm_OtherIncomeDeductionsExcludingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 11,288pnm_OtherIncomeDeductionsExcludingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 13,290pnm_OtherIncomeDeductionsExcludingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Interest charges |  |  |  |  |  |  |  |  | (79,442)us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | (79,175)us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | (76,101)us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Earnings before Income Taxes |  |  |  |  |  |  |  |  | 154,086us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 151,480us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 156,314us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Income Taxes |  |  |  |  |  |  |  |  | 52,633us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 48,804us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 50,713us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Net Earnings |  |  |  |  |  |  |  |  | 101,453us-gaap_ProfitLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 102,676us-gaap_ProfitLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 105,601us-gaap_ProfitLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Valencia non-controlling interest |  |  |  |  |  |  |  |  | (14,127)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | (14,521)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | (14,050)us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Preferred Stock Dividend Requirements of Subsidiary |  |  |  |  |  |  |  |  | (528)us-gaap_DividendsPreferredStock / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | (528)us-gaap_DividendsPreferredStock / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | (528)us-gaap_DividendsPreferredStock / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Segment earnings (loss) attributable to PNMR |  |  |  |  |  |  |  |  | 86,798us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 87,627us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 91,023us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Gross property additions |  |  |  |  |  |  |  |  | 316,800us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 239,906us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 196,800us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Total Assets | 4,473,652us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember |  |  |  | 4,227,616us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember |  |  |  | 4,473,652us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 4,227,616us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 4,163,907us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
Goodwill | 51,632us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember |  |  |  | 51,632us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember |  |  |  | 51,632us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 51,632us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember | 51,632us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pnm_PublicServiceCompanyOfNewMexicoMember
TNMP [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information, Profit (Loss) [Abstract] |  |  |  |  |  |  |  |  |  |  |
Electric Operating Revenues |  |  |  |  |  |  |  |  | 287,939us-gaap_ElectricUtilityRevenue / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 271,611us-gaap_ElectricUtilityRevenue / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 250,140us-gaap_ElectricUtilityRevenue / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Cost of energy |  |  |  |  |  |  |  |  | 67,930us-gaap_CostOfGoodsSoldElectric / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 57,606us-gaap_CostOfGoodsSoldElectric / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 46,201us-gaap_CostOfGoodsSoldElectric / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Margin |  |  |  |  |  |  |  |  | 220,009pnm_GrossMargin / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 214,005pnm_GrossMargin / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 203,939pnm_GrossMargin / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Other operating expenses |  |  |  |  |  |  |  |  | 84,365pnm_OtherOperatingExpenses / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 91,601pnm_OtherOperatingExpenses / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 87,079pnm_OtherOperatingExpenses / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Depreciation and amortization |  |  |  |  |  |  |  |  | 50,056us-gaap_CostOfServicesDepreciationAndAmortization / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 50,219us-gaap_CostOfServicesDepreciationAndAmortization / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 49,340us-gaap_CostOfServicesDepreciationAndAmortization / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Operating income |  |  |  |  |  |  |  |  | 85,588us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 72,185us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 67,520us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Interest income |  |  |  |  |  |  |  |  | 0us-gaap_InvestmentIncomeInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 0us-gaap_InvestmentIncomeInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 1us-gaap_InvestmentIncomeInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Gain on sale of First Choice |  |  |  |  |  |  |  |  |  |  | 0pnm_GainOnSaleOfBusinessSegment / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Other income (deductions) |  |  |  |  |  |  |  |  | 2,138pnm_OtherIncomeDeductionsExcludingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 1,919pnm_OtherIncomeDeductionsExcludingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 2,739pnm_OtherIncomeDeductionsExcludingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Interest charges |  |  |  |  |  |  |  |  | (27,396)us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | (27,393)us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | (28,161)us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Earnings before Income Taxes |  |  |  |  |  |  |  |  | 60,330us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 46,711us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 42,099us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Income Taxes |  |  |  |  |  |  |  |  | 22,523us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 17,621us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 15,352us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Net Earnings |  |  |  |  |  |  |  |  | 37,807us-gaap_ProfitLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 29,090us-gaap_ProfitLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 26,747us-gaap_ProfitLoss / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Valencia non-controlling interest |  |  |  |  |  |  |  |  | 0us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 0us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 0us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Preferred Stock Dividend Requirements of Subsidiary |  |  |  |  |  |  |  |  | 0us-gaap_DividendsPreferredStock / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 0us-gaap_DividendsPreferredStock / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 0us-gaap_DividendsPreferredStock / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Segment earnings (loss) attributable to PNMR |  |  |  |  |  |  |  |  | 37,807us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 29,090us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 26,747us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Gross property additions |  |  |  |  |  |  |  |  | 127,191us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 89,117us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 92,973us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Total Assets | 1,240,241us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember |  |  |  | 1,162,431us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember |  |  |  | 1,240,241us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 1,162,431us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 1,086,229us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Goodwill | 226,665us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember |  |  |  | 226,665us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember |  |  |  | 226,665us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 226,665us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember | 226,665us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = pnm_TexasNewMexicoPowerCompanyMember
Corporate and Other [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information, Profit (Loss) [Abstract] |  |  |  |  |  |  |  |  |  |  |
Electric Operating Revenues |  |  |  |  |  |  |  |  | 0us-gaap_ElectricUtilityRevenue / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 0us-gaap_ElectricUtilityRevenue / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (1)us-gaap_ElectricUtilityRevenue / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Cost of energy |  |  |  |  |  |  |  |  | 0us-gaap_CostOfGoodsSoldElectric / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 0us-gaap_CostOfGoodsSoldElectric / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 0us-gaap_CostOfGoodsSoldElectric / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Margin |  |  |  |  |  |  |  |  | 0pnm_GrossMargin / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 0pnm_GrossMargin / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (1)pnm_GrossMargin / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Other operating expenses |  |  |  |  |  |  |  |  | (14,450)pnm_OtherOperatingExpenses / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (18,308)pnm_OtherOperatingExpenses / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (17,862)pnm_OtherOperatingExpenses / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Depreciation and amortization |  |  |  |  |  |  |  |  | 13,054us-gaap_CostOfServicesDepreciationAndAmortization / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 12,836us-gaap_CostOfServicesDepreciationAndAmortization / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 17,542us-gaap_CostOfServicesDepreciationAndAmortization / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Operating income |  |  |  |  |  |  |  |  | 1,396us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 5,472us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 319us-gaap_OperatingIncomeLoss / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Interest income |  |  |  |  |  |  |  |  | (74)us-gaap_InvestmentIncomeInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (139)us-gaap_InvestmentIncomeInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (172)us-gaap_InvestmentIncomeInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Gain on sale of First Choice |  |  |  |  |  |  |  |  |  |  | 1,012pnm_GainOnSaleOfBusinessSegment / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Other income (deductions) |  |  |  |  |  |  |  |  | (2,302)pnm_OtherIncomeDeductionsExcludingInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (13,575)pnm_OtherIncomeDeductionsExcludingInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (7,954)pnm_OtherIncomeDeductionsExcludingInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Interest charges |  |  |  |  |  |  |  |  | (12,789)us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (14,880)us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (16,583)us-gaap_InterestExpense / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Earnings before Income Taxes |  |  |  |  |  |  |  |  | (13,769)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (23,122)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (23,378)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Income Taxes |  |  |  |  |  |  |  |  | (5,418)us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (6,912)us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (11,155)us-gaap_IncomeTaxExpenseBenefit / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Net Earnings |  |  |  |  |  |  |  |  | (8,351)us-gaap_ProfitLoss / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (16,210)us-gaap_ProfitLoss / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (12,223)us-gaap_ProfitLoss / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Valencia non-controlling interest |  |  |  |  |  |  |  |  | 0us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 0us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 0us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Preferred Stock Dividend Requirements of Subsidiary |  |  |  |  |  |  |  |  | 0us-gaap_DividendsPreferredStock / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 0us-gaap_DividendsPreferredStock / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 0us-gaap_DividendsPreferredStock / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Segment earnings (loss) attributable to PNMR |  |  |  |  |  |  |  |  | (8,351)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (16,210)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | (12,223)us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Gross property additions |  |  |  |  |  |  |  |  | 16,667us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 19,016us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 19,136us-gaap_PaymentsToAcquireProductiveAssets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Total Assets | 115,432us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |  |  |  | 110,163us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |  |  |  | 115,432us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 110,163us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | 122,447us-gaap_Assets / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember
Goodwill | $ 0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |  |  |  | $ 0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember |  |  |  | $ 0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | $ 0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember | $ 0us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = us-gaap_CorporateAndOtherMember

X
- Definition Gain on Sale of Business Segment + References No definition available. + Details
Name: | pnm_GainOnSaleOfBusinessSegment
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate revenues less cost of energy + References No definition available. + Details
Name: | pnm_GrossMargin
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Other Income Deductions Excluding Interest + References No definition available. + Details
Name: | pnm_OtherIncomeDeductionsExcludingInterest
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Other Operating Expenses + References No definition available. + Details
Name: | pnm_OtherOperatingExpenses
Namespace Prefix: | pnm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + 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 210.5-02.18) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 18 -Article 5 + Details
Name: | us-gaap_Assets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Total costs related to electricity produced and sold during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 2 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(b)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_CostOfGoodsSoldElectric
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Depreciation of property, plant and equipment directly related to services rendered by an entity during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(d)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_CostOfServicesDepreciationAndAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of paid and unpaid preferred stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 405 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817 + Details
Name: | us-gaap_DividendsPreferredStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The aggregate revenue, whether regulated or unregulated, derived from the generation, transmission and distribution of electricity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(b)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 + Details
Name: | us-gaap_ElectricUtilityRevenue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266 + Details
Name: | us-gaap_Goodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 940 -SubTopic 20 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=35710027&loc=d3e41242-110953 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 10 -Article 5 + Details
Name: | us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Article 4 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Income Tax Expense (or Benefit) -URI http://asc.fasb.org/extlink&oid=6515339 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319 + Details
Name: | us-gaap_IncomeTaxExpenseBenefit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of the cost of borrowed funds accounted for as interest expense. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.9) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 9 -Article 9 + Details
Name: | us-gaap_InterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(b)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_InvestmentIncomeInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of Net Income (Loss) attributable to noncontrolling interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 55 -Paragraph 4J -URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591551-111686 + Details
Name: | us-gaap_NetIncomeLossAttributableToNoncontrollingInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1377-109256 + Details
Name: | us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The net result for the period of deducting operating expenses from operating revenues. + References No definition available. + Details
Name: | us-gaap_OperatingIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets. + 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 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireProductiveAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 55 -Paragraph 4K -URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591552-111686 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569616-111683 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 55 -Paragraph 4J -URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591551-111686 + Details
Name: | us-gaap_ProfitLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

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

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=pnm_TexasNewMexicoPowerCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=us-gaap_CorporateAndOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |