Fair Value of Derivative and Other Financial Instruments, Debt Maturities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013
PNMR and PNM [Member]
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract]
Available-for-sale debt securities, Within 1 year	$ 3,025
Available-for-sale debt securities, After 1 year through 5 years	24,068
Available-for-sale debt securities, After 5 years through 10 years	10,128
Available-for-sale debt securities, After 10 years through 15 years	6,136
Available-for-sale debt securities, After 15 years through 20 years	10,331
Available-for-sale debt securities, After 20 years	37,426
Available-for-sale debt securities	91,114
PNM Resources [Member]
Held-to-maturity Securities, Debt Maturities, Fair Value [Abstract]
Held-to-maturity debt securities, Due within 1 year	1,149
Held-to-maturity debt securities, After 1 year through 5 years	57,497
Held-to-maturity debt securities, After 5 years through 10 years	0
Held to Maturity Securities, Debt Maturities, after Ten Years Through Fifteen Years, Fair Value	0
Held to Maturity Securities, Debt Maturities, after Fifteen Years Through Twenty Years, Fair Value	0
Held to Maturity Securities, Debt Maturities, after Twenty Years, Fair Value	0
Held-to-maturity debt securities	58,646
Public Service Company of New Mexico [Member]
Held-to-maturity Securities, Debt Maturities, Fair Value [Abstract]
Held-to-maturity debt securities, Due within 1 year	1,149
Held-to-maturity debt securities, After 1 year through 5 years	56,130
Held-to-maturity debt securities, After 5 years through 10 years	0
Held to Maturity Securities, Debt Maturities, after Ten Years Through Fifteen Years, Fair Value	0
Held to Maturity Securities, Debt Maturities, after Fifteen Years Through Twenty Years, Fair Value	0
Held to Maturity Securities, Debt Maturities, after Twenty Years, Fair Value	0
Held-to-maturity debt securities	$ 57,279