Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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-Publisher FASB

-Name Accounting Standards Codification

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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

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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.

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

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-Glossary Investing Activities

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Fair Value of Derivative and Other Financial Instruments - Available for Sale Securities (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	$ 400,000	$ 500,000
PNMR and PNM [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	257,464,000		250,145,000
Available-for-sale Securities, Gross Unrealized Gain	48,842,000		46,348,000
Proceeds from sales	31,852,000	22,804,000
Gross realized gains	5,135,000	3,118,000
Gross realized (losses)	(1,541,000)	(1,039,000)
PNMR and PNM [Member] \| Cash and equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	5,142,000		8,276,000
Available-for-sale Securities, Gross Unrealized Gain	0		0
PNMR and PNM [Member] \| Domestic value [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	46,129,000		45,340,000
Available-for-sale Securities, Gross Unrealized Gain	16,786,000		17,418,000
PNMR and PNM [Member] \| Domestic growth [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	78,013,000		74,053,000
Available-for-sale Securities, Gross Unrealized Gain	22,849,000		21,354,000
PNMR and PNM [Member] \| International and other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	17,478,000		16,599,000
Available-for-sale Securities, Gross Unrealized Gain	995,000		156,000
PNMR and PNM [Member] \| U.S. Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	21,912,000		22,563,000
Available-for-sale Securities, Gross Unrealized Gain	1,256,000		903,000
PNMR and PNM [Member] \| Municipals [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	73,554,000		68,973,000
Available-for-sale Securities, Gross Unrealized Gain	6,198,000		5,851,000
PNMR and PNM [Member] \| Corporate and other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	15,236,000		14,341,000
Available-for-sale Securities, Gross Unrealized Gain	758,000		666,000
Fair Value, Measurements, Recurring [Member] \| PNMR and PNM [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	257,464,000		250,145,000
Fair Value, Measurements, Recurring [Member] \| PNMR and PNM [Member] \| Nuclear Decommissioning Trust [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	251,800,000		244,600,000
Fair Value, Measurements, Recurring [Member] \| PNMR and PNM [Member] \| Mine Reclamation Trust [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	5,700,000		5,500,000
Fair Value, Measurements, Recurring [Member] \| PNMR and PNM [Member] \| Cash and equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	5,142,000		8,276,000
Fair Value, Measurements, Recurring [Member] \| PNMR and PNM [Member] \| Domestic value [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	46,129,000		45,340,000
Fair Value, Measurements, Recurring [Member] \| PNMR and PNM [Member] \| Domestic growth [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	78,013,000		74,053,000
Fair Value, Measurements, Recurring [Member] \| PNMR and PNM [Member] \| International and other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	17,478,000		16,599,000
Fair Value, Measurements, Recurring [Member] \| PNMR and PNM [Member] \| U.S. Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	21,912,000		22,563,000
Fair Value, Measurements, Recurring [Member] \| PNMR and PNM [Member] \| Municipals [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	73,554,000		68,973,000
Fair Value, Measurements, Recurring [Member] \| PNMR and PNM [Member] \| Corporate and other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Fair value	$ 15,236,000		$ 14,341,000