Long-term debt, required quarterly payment

No definition available.

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- Definition

Number of applicable financial covenants

+ References

No definition available.

+ Details

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- Definition

Payments to fund long-term loans to unaffiliated third party

+ References

No definition available.

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- Definition

Public Utilities, Maturity term over which financings require regulator approval

+ References

No definition available.

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- Definition

Ratio of debt to capital, maximum

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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- 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.

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-Name Accounting Standards Codification
-Topic 210
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

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Financing - Financing Activities (Details)			1 Months Ended	9 Months Ended	12 Months Ended
Financing - Financing Activities (Details)	Nov. 01, 2016 USD ($)	Feb. 01, 2016 USD ($)	Jun. 21, 2016 USD ($)	Sep. 30, 2016 USD ($) covenant	Dec. 31, 2015 USD ($)	Oct. 21, 2016 USD ($)	Sep. 27, 2016 USD ($)	May 20, 2016 USD ($)	Dec. 17, 2015 USD ($)	Sep. 30, 2015	Mar. 09, 2015 USD ($)
Debt Instrument [Line Items]
Number of applicable financial covenants \| covenant				1
Fixed interest rate										1.927%
Cash Flow Hedging [Member] \| Fair Value, Inputs, Level 2 [Member]
Debt Instrument [Line Items]
Fair value gain (loss)				$ (700,000)	$ 100,000
Public Service Company of New Mexico [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Maturity term over which financings require regulator approval				18 months
NM Capital [Member] \| Coal Supply [Member] \| San Juan Generating Station [Member]
Debt Instrument [Line Items]
Payments to fund long-term loans to unaffiliated third party		$ 125,000,000.0
Line of Credit [Member]
Debt Instrument [Line Items]
Ratio of debt to capital (less than or equal to)				65.00%
PNMR 2015 Term Loan Agreement [Member]
Debt Instrument [Line Items]
Term loans											$ 150,000,000.0
Interest rate				1.42%
BTMU Term Loan Agreement [Member] \| NM Capital [Member]
Debt Instrument [Line Items]
Term loans		$ 125,000,000.0		$ 107,800,000.0
Stated interest rate				3.51%
Estimated principal payments				$ 45,100,000
BTMU Term Loan Agreement [Member] \| NM Capital [Member] \| Minimum [Member] \| Subsequent event [Member]
Debt Instrument [Line Items]
Long-term debt, required quarterly payment	$ 5,000,000.0
First Mortgage Bonds [Member] \| Texas-New Mexico Power Company [Member] \| First Mortgage Bonds, 3.53%, due 2026, Series 2016A [Member]
Debt Instrument [Line Items]
Stated interest rate									3.53%
Aggregate principal amount									$ 60,000,000.0
PNM 2016 Term Loan Agreement [Member] \| Public Service Company of New Mexico [Member]
Debt Instrument [Line Items]
Stated interest rate				1.15%
Aggregate principal amount								$ 175,000,000.0
PNM 2014 Multi-Draw Term Loan Agreement [Member] \| Public Service Company of New Mexico [Member]
Debt Instrument [Line Items]
Repayments of debt			$ 125,000,000
Pollution Control Bonds [Member] [Member] \| Public Service Company of New Mexico [Member] \| Pollution Control Revenue Bonds 1 Point 875 Percent, due 2021 [Member]
Debt Instrument [Line Items]
Stated interest rate							1.875%
Aggregate principal amount							$ 146,000,000.0
Pollution Control Bonds [Member] [Member] \| Public Service Company of New Mexico [Member] \| Pollution Control Revenue Bonds 1 Point 875 Percent, due 2021, 2016 Series A [Member]
Debt Instrument [Line Items]
Aggregate principal amount							46,000,000.0
Pollution Control Bonds [Member] [Member] \| Public Service Company of New Mexico [Member] \| Pollution Control Revenue Bonds 1 Point 875 Percent, due 2021, 2016 Series B [Member]
Debt Instrument [Line Items]
Aggregate principal amount							$ 100,000,000.0
Letter of Credit [Member] \| PNMR [Member] \| Subsequent event [Member] \| Letter or credit, 30 mil JP Morgan [Member]
Debt Instrument [Line Items]
Aggregate principal amount						$ 30,300,000.0