Debt Instruments, NMPRC Approved credit facility

No definition available.

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- Definition

Short Term Debt Due to Related Party

+ References

No definition available.

+ Details

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- Definition

Amount of assets pledged to secure a debt instrument.

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- Definition

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

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13433-108611

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Period Type:	instant

- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Period Type:	instant

- Definition

The number of derivative instruments of a particular group held by the entity.

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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- 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.

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Balance Type:	credit
Period Type:	instant

- Definition

Maximum period the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Cash and investments whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements. For use in an unclassified balance sheet.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Period Type:	instant

- 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

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- Definition

Weighted average interest rate of short-term debt outstanding calculated at point in time.

+ References

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Financing - Short-term Debt and Liquidity (Details)	9 Months Ended	12 Months Ended
Financing - Short-term Debt and Liquidity (Details)	Sep. 30, 2019 USD ($)	Dec. 31, 2017 USD ($) derivative	Oct. 25, 2019 USD ($)	Jul. 22, 2019 USD ($)	Jul. 21, 2019 USD ($)	Feb. 22, 2019 USD ($)	Feb. 21, 2019 USD ($)	Jan. 18, 2019 USD ($)	Dec. 31, 2018 USD ($)
Short-term Debt [Line Items]
Financing capacity				$ 50,000,000.0	$ 40,000,000.0	$ 25,000,000.0	$ 24,500,000
Short-term debt	$ 289,600,000								$ 235,900,000
Letters of credit outstanding	4,700,000
PNMR 2018 One-Year Term Loan
Short-term Debt [Line Items]
Short-term debt	$ 150,000,000								150,000,000
Term of loan	1 year
Debt issued	$ 150,000,000.0
PNMR 2018 One-Year Term Loan \| PNMR
Short-term Debt [Line Items]
Weighted-average interest rate for short-term debt	2.81%
PNMR Development Revolving Credit Facility
Short-term Debt [Line Items]
Short-term debt	$ 38,900,000								6,000,000
Variable Rate Short-Term Debt
Short-term Debt [Line Items]
Term of derivatives		4 years
Debt issued		$ 50,000,000.0
PNMR Development Term Loan
Short-term Debt [Line Items]
Debt issued	$ 90,000,000.0
PNMR Revolving Credit Facility \| PNMR
Short-term Debt [Line Items]
Weighted-average interest rate for short-term debt	3.29%
PNMR Development Revolving Credit Facility \| PNMR
Short-term Debt [Line Items]
Weighted-average interest rate for short-term debt	3.05%
TNMP Revolving Credit Facility
Short-term Debt [Line Items]
Weighted-average interest rate for short-term debt	2.77%
PNM
Short-term Debt [Line Items]
Short-term debt	$ 0								42,400,000
Letters of credit outstanding	2,500,000
Short-term debt – affiliate	0								19,800,000
Long-term debt	100,300,000
PNM \| Lines of credit
Short-term Debt [Line Items]
NMPRC approved credit facility	40,000,000.0
Short-term debt	0								10,000,000
PNM \| PNM 2019 Term Loan
Short-term Debt [Line Items]
Debt issued	250,000,000.0							$ 250,000,000.0
TNMP
Short-term Debt [Line Items]
Short-term debt	15,000,000								17,500,000
Letters of credit outstanding	100,000
Short-term debt – affiliate	800,000								100,000
TNMP \| TNMP Term Loan Agreement
Short-term Debt [Line Items]
Debt issued	35,000,000.0
PNMR Development
Short-term Debt [Line Items]
Short-term debt – affiliate	100,000								500,000
Revolving credit facility
Short-term Debt [Line Items]
Financing capacity	300,000,000.0
Short-term debt	85,700,000								20,000,000
Revolving credit facility \| PNM
Short-term Debt [Line Items]
Financing capacity	400,000,000.0
Short-term debt	0								32,400,000
Revolving credit facility \| TNMP
Short-term Debt [Line Items]
Financing capacity	75,000,000.0
Short-term debt	15,000,000								17,500,000
Revolving credit facility \| TNMP \| First mortgage bonds
Short-term Debt [Line Items]
Collateral amount	75,000,000.0
Interest rate contract
Short-term Debt [Line Items]
Number of derivatives \| derivative		3
Interest rate 1 \| Variable Rate Short-Term Debt
Short-term Debt [Line Items]
Fixed interest rate		1.926%
Interest rate 2 \| Variable Rate Short-Term Debt
Short-term Debt [Line Items]
Fixed interest rate		1.823%
Interest rate 3 \| Variable Rate Short-Term Debt
Short-term Debt [Line Items]
Fixed interest rate		1.629%
Interest rate 3 \| Level 2 \| Cash Flow Hedge
Short-term Debt [Line Items]
Current derivative liability	$ 600,000
Derivative, fair value									$ 1,000,000.0
Subsequent event
Short-term Debt [Line Items]
Remaining borrowing capacity			$ 714,100,000
Subsequent event \| PNMR
Short-term Debt [Line Items]
Remaining borrowing capacity			215,900,000
Consolidated invested cash			900,000
Subsequent event \| PNM
Short-term Debt [Line Items]
Remaining borrowing capacity			397,500,000
Consolidated invested cash			20,500,000
Subsequent event \| PNM \| Lines of credit
Short-term Debt [Line Items]
Remaining borrowing capacity			40,000,000.0
Subsequent event \| TNMP
Short-term Debt [Line Items]
Remaining borrowing capacity			59,600,000
Consolidated invested cash			0
Subsequent event \| PNMR Development
Short-term Debt [Line Items]
Short-term debt – affiliate			100,000
Remaining borrowing capacity			$ 1,100,000