Financing, Financing Activities (Details) (USD $)	6 Months Ended						6 Months Ended							0 Months Ended							0 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Public Service Company of New Mexico [Member]	Dec. 31, 2012 Public Service Company of New Mexico [Member]	Jun. 30, 2013 Texas-New Mexico Power Company [Member]	Jun. 30, 2012 Texas-New Mexico Power Company [Member]	Mar. 31, 2013 Texas-New Mexico Power Company [Member]	Mar. 06, 2013 Texas-New Mexico Power Company [Member]	Dec. 31, 2012 Texas-New Mexico Power Company [Member]	Jun. 30, 2013 PNMR Term Loan Agreement [Member]	Dec. 31, 2012 PNMR Term Loan Agreement [Member]	Apr. 22, 2013 First Mortgage Bonds [Member] Texas-New Mexico Power Company [Member]	Apr. 03, 2013 First Mortgage Bonds [Member] First Mortgage Bonds Due 2014, Series 2009A, at 9 point 50 percent [Member] Texas-New Mexico Power Company [Member]	Mar. 06, 2013 First Mortgage Bonds [Member] First Mortgage Bonds Due 2014, Series 2009A, at 9 point 50 percent [Member] Texas-New Mexico Power Company [Member]	Apr. 03, 2013 First Mortgage Bonds [Member] First Mortgage Bonds, due 2043, Series 2013A [Member] Texas-New Mexico Power Company [Member]	Mar. 06, 2013 First Mortgage Bonds [Member] First Mortgage Bonds, due 2043, Series 2013A [Member] Texas-New Mexico Power Company [Member]	Jun. 30, 2013 Senior Unsecured Note, Due 2015, at 9 point 25 percent [Member]	Jun. 30, 2013 Senior Unsecured Note, Due 2015, at 9 point 25 percent [Member]	Apr. 22, 2013 Notes Payable to Banks [Member] PNM Term Loan Agreement [Member]	Jun. 30, 2013 Notes Payable to Banks [Member] PNM Term Loan Agreement [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount										$ 1,000						$ 265,500,000	$ 93,200,000			$ 8,300,000
Debt Instrument, Interest Rate, Stated Percentage															9.50%	9.50%	6.95%	6.95%	9.25%			1.45%
Debt Instrument, Cash Offered for Debt Exchanged										140
Cash paid in debt exchange	(13,048,000)	0					(13,048,000)	0						13,000,000
Debt Instrument, Cash for Bond Exchange Conversion																		0.14
Debt Instrument, Unamortized Premium																	23,200,000
Short-term debt			160,000,000	158,700,000	0	21,100,000			25,000,000		0	100,000,000	100,000,000								75,000,000
Repayments of Lines of Credit																					75,000,000
Unsecured Long-term Debt, Noncurrent	$ 9,400,000