Schedule I - Condensed Financial Information of Parent Company (Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Assets
Cash and cash equivalents	$ 2,533	$ 8,985	$ 15,091	$ 15,404
Income taxes receivable	7,066	101,477
Other, net	34,590	31,490
Total current assets	401,539	442,191
Property, plant and equipment, net of accumulated depreciation of $9,167 and $8,262	3,933,911	3,746,487
Other Long-term assets	1,835	5,599
Total Assets	5,500,210	5,372,583	5,204,613
Liabilities and Stockholders' Equity
Short-term debt	149,200	158,700
Current maturities of long-term debt	75,000	2,530
Accrued interest and taxes	49,600	52,003
Other current liabilities	77,105	75,407
Total current liabilities	492,671	434,103
Long-term Debt	1,670,420	1,669,760
Total liabilities	3,738,083	3,672,024
Common stock (no par value; 120,000,000 shares authorized; issued and outstanding 79,653,624 shares)	1,178,369	1,182,819
Accumulated other comprehensive income (loss), net of tax	(58,140)	(81,630)	(66,856)	(68,666)
Retained earnings	553,340	506,998
Total PNMR common stockholders' equity	1,673,569	1,608,187
Total liabilities and stockholders' equity	5,500,210	5,372,583
PNM Resources [Member]
Assets
Cash and cash equivalents	92	29	241	303
Intercompany receivables	136,387	108,875
Income taxes receivable	14,989	41,434
Other, net	8,544	2,204
Total current assets	160,012	152,542
Property, plant and equipment, net of accumulated depreciation of $9,167 and $8,262	26,601	25,642
Long-term Investments	0	3,651
Investment in subsidiaries	1,683,321	1,688,168
Other Long-term assets	53,892	49,302
Total long-term assets	1,763,814	1,766,763
Total Assets	1,923,826	1,919,305
Liabilities and Stockholders' Equity
Short-term debt	100,000	137,600
Short-term debt-affiliate	8,819	8,819
Current maturities of long-term debt	0	2,530
Accrued interest and taxes	2,797	3,127
Other current liabilities	16,876	13,218
Total current liabilities	128,492	165,294
Long-term Debt	118,766	142,592
Other long-term liabilities	2,999	3,232
Total liabilities	250,257	311,118
Common stock (no par value; 120,000,000 shares authorized; issued and outstanding 79,653,624 shares)	1,178,369	1,182,819
Accumulated other comprehensive income (loss), net of tax	(58,140)	(81,630)
Retained earnings	553,340	506,998
Total PNMR common stockholders' equity	1,673,569	1,608,187
Total liabilities and stockholders' equity	$ 1,923,826	$ 1,919,305