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- Definition

Debt Securities Available For Sale Realized Loss

+ References

No definition available.

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- Definition

(Increase)/Decrease in other than temporary losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities

+ References

No definition available.

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- 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
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- Definition

This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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- Definition

This item represents the fair value of securities categorized as held-to-maturity which are in an unrealized loss position.

+ References

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- Definition

Amount before tax of other than temporary impairment (OTTI) loss on investments in available-for-sale and held-to-maturity debt securities, recognized in other comprehensive loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

The cash inflow associated with the sale of debt securities classified as available-for-sale securities.

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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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Fair Value of Derivative and Other Financial Instruments - Available for Sale Securities (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities for which carrying value exceeds fair value	$ 0
Held-to-maturity securities for which carrying value exceeds fair value	0
Impairments considered to be other than temporary	0
PNM
Schedule of Available-for-sale Securities [Line Items]
(Increase)/decrease in other than temporary losses of available-for-sale securities, net portion recognized in earnings	(1,200,000)	$ 1,100,000
Proceeds from sales	626,729,000	266,388,000
Gross realized gains	6,021,000	8,645,000
Gross realized (losses)	4,677,000	3,085,000
PNM \| Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Gross realized gains	324,003,000	323,524,000
PNM \| Nuclear Decommissioning Trust \| Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Fair Value	294,000,000		$ 293,700,000
PNM \| Mine Reclamation Trust \| Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Fair Value	30,000,000		$ 29,800,000
PNM \| Cash and cash equivalents \| Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Gross realized gains	22,810,000	52,636,000
PNM \| Domestic value \| Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Gross realized gains		40,032,000
PNM \| Domestic growth \| Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Gross realized gains		35,456,000
PNM \| International and other \| Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Gross realized gains		45,867,000
PNM \| U.S. Government \| Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Gross realized gains	23,829,000	34,317,000
PNM \| Municipals \| Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Gross realized gains	35,782,000	48,076,000
PNM \| Corporate and other \| Fair Value, Measurements, Recurring
Schedule of Available-for-sale Securities [Line Items]
Gross realized gains	$ 114,813,000	$ 67,140,000