Pension and Other Postretirement Benefits - Pension Benefit Payments are Expected to be Paid (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Public Service Company of New Mexico \| Pension Plan
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	$ 46,312
2022	45,583
2023	44,299
2024	43,066
2025	41,869
2026 - 2030	188,950
Public Service Company of New Mexico \| Other Postretirement Benefits
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	6,455
2022	6,132
2023	5,960
2024	5,711
2025	5,357
2026 - 2030	22,474
Public Service Company of New Mexico \| Executive Retirement Program
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	1,341
2022	1,303
2023	1,259
2024	1,210
2025	1,156
2026 - 2030	4,856
Texas-New Mexico Power Company \| Pension Plan
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	5,301
2022	5,193
2023	4,936
2024	4,702
2025	4,589
2026 - 2030	19,829
Texas-New Mexico Power Company \| Other Postretirement Benefits
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	649
2022	678
2023	698
2024	709
2025	713
2026 - 2030	3,400
Texas-New Mexico Power Company \| Executive Retirement Program
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	93
2022	90
2023	85
2024	80
2025	73
2026 - 2030	$ 252

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Amount of benefit for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following current fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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Amount of benefit for defined benefit plan expected to be paid in next fiscal year following current fiscal year.

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Amount of benefit for defined benefit plan expected to be paid in second fiscal year following current fiscal year.

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