Financing, Short-term Debt (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Oct. 24, 2014 Subsequent Event [Member]	Sep. 30, 2014 PNMR Term Loan Agreement [Member]	Dec. 31, 2013 PNMR Term Loan Agreement [Member]	Oct. 24, 2014 PNM Resources [Member] Subsequent Event [Member]	Oct. 24, 2014 Public Service Company of New Mexico [Member] Subsequent Event [Member]	Oct. 24, 2014 Public Service Company of New Mexico [Member] Subsequent Event [Member] Affiliated Entity [Member]	Sep. 30, 2014 Public Service Company of New Mexico [Member] Local Lines of Credit [Member]	Jan. 08, 2014 Public Service Company of New Mexico [Member] Local Lines of Credit [Member]	Dec. 31, 2013 Public Service Company of New Mexico [Member] Local Lines of Credit [Member]	Oct. 24, 2014 Public Service Company of New Mexico [Member] Local Lines of Credit [Member] Subsequent Event [Member]	Sep. 30, 2014 Public Service Company of New Mexico [Member] Intercompany loan agreements [Member]	Oct. 24, 2014 Texas-New Mexico Power Company [Member] Subsequent Event [Member]	Oct. 24, 2014 Texas-New Mexico Power Company [Member] Subsequent Event [Member] Affiliated Entity [Member]	Sep. 30, 2014 Texas-New Mexico Power Company [Member] Intercompany loan agreements [Member]	Sep. 30, 2014 Line of Credit [Member]	Dec. 31, 2013 Line of Credit [Member]	Sep. 30, 2014 Revolving Credit Facility [Member] PNM Resources [Member]	Dec. 31, 2013 Revolving Credit Facility [Member] PNM Resources [Member]	Sep. 30, 2014 Revolving Credit Facility [Member] Public Service Company of New Mexico [Member]	Dec. 31, 2013 Revolving Credit Facility [Member] Public Service Company of New Mexico [Member]	Sep. 30, 2014 Revolving Credit Facility [Member] Texas-New Mexico Power Company [Member]	Dec. 31, 2013 Revolving Credit Facility [Member] Texas-New Mexico Power Company [Member]	Sep. 30, 2014 Revolving Credit Facility [Member] Texas-New Mexico Power Company [Member] First Mortgage Bonds Due 2014, Series 2009A, at 9 point 50 percent [Member]
Short-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity																			$ 300,000,000.0		$ 400,000,000.0		$ 75,000,000.0
Debt Instrument, Collateral Amount																									75,000,000
Debt Instruments, NMPRC Approved credit facility										50,000,000
Short-term debt - affiliate													6,500,000			19,100,000
Short-term Debt, Weighted Average Interest Rate				1.01%
Short-term debt	100,000,000	149,200,000		100,000,000	100,000,000				0		0						100,000,000	149,200,000	0	0	0	49,200,000	0	0
Line of Credit Facility, Remaining Borrowing Capacity			814,000,000			292,300,000	396,800,000					50,000,000		74,900,000
Short-term debt – affiliate								7,400,000							25,700,000
Restricted Cash and Investments						$ 23,100,000	$ 0							$ 0