XML 56 R33.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Regulatory and Rate Matters (Tables) | 6 Months Ended
--- | ---
Jun. 30, 2017
Regulated Operations [Abstract] |
Schedule of Rate Increases for Transmission Costs | The following sets forth TNMP’s recent interim transmission cost rate increases:
Effective Date |  | Approved Increase in Rate Base |  | Annual Increase in Revenue
|  | (In millions)
September 10, 2015 |  | $ | 7.0 |  |  | $ | 1.4 |
March 23, 2016 |  | 25.8 |  |  | 4.3 |
September 8, 2016 |  | 9.5 |  |  | 1.8 |
March 14, 2017 |  | 30.2 |  |  | 4.8 |

X
- Definition Schedule of Rate Increases for Transmission Costs [Table Text Block] + References No definition available. + Details
Name: | pnm_ScheduleofRateIncreasesforTransmissionCostsTableTextBlock
Namespace Prefix: | pnm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_RegulatedOperationsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration