Variable Interest Entities (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($) MW	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) MW	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Jan. 31, 2016 USD ($)
Results of Operations
Operating revenues	$ 729,888	$ 554,551	$ 1,673,736	$ 1,345,798
Operating expenses	547,125	402,822	1,336,513	1,076,700
Earnings attributable to non-controlling interest	4,172	4,229	10,897	11,643
Financial Position
Current assets	409,774		409,774		$ 324,600
Assets	9,028,890	8,256,070	9,028,890	8,256,070	8,666,885
Current liabilities	666,469		666,469		664,213
Owners’ equity – non-controlling interest	53,847		53,847		55,405
San Juan Generating Station | Coal supply
Variable Interest Entity [Line Items]
Cash used to support bank letter or credit arrangement						$ 30,300
PNM
Results of Operations
Operating revenues	597,337	435,523	1,312,800	1,030,685
Operating expenses	457,422	320,960	1,078,434	831,305
Earnings attributable to non-controlling interest	4,172	4,229	10,897	11,643
Financial Position
Current assets	331,221		331,221		266,689
Assets	6,113,416		6,113,416		6,060,133
Current liabilities	497,059		497,059		495,902
Owners’ equity – non-controlling interest	53,847		53,847		55,405
PNM | Valencia
Variable Interest Entity [Line Items]
Payment for fixed costs	5,000	5,000	14,600	14,900
Payment for variable costs	700	700	$ 1,100	1,600
Long-term contract option to purchase, ownership percentage (up to)			50.00%
Long-term contract option to purchase, purchase price - percentage of adjusted NBV			50.00%
Long-term contract option to purchase, purchase price - percentage of FMV			50.00%
Results of Operations
Operating revenues	5,640	5,719	$ 15,670	16,425
Operating expenses	1,468	1,490	4,773	4,782
Earnings attributable to non-controlling interest	4,172	$ 4,229	10,897	$ 11,643
Financial Position
Current assets	3,918		3,918		3,042
Net property, plant, and equipment	50,780		50,780		52,908
Assets	54,698		54,698		55,950
Current liabilities	851		851		545
Owners’ equity – non-controlling interest	$ 53,847		$ 53,847		$ 55,405
PNM | Purchased through May 2028 | Valencia
Variable Interest Entity [Line Items]
Number of megawatts purchased (in megawatts) | MW	155		155