Schedule I - Condensed Financial Information of Parent Company - Statement of Cash flow (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash Flows From Operating Activities:
Net Cash Flows From Operating Activities	$ 551,171	$ 567,284	$ 547,873
Cash Flows From Investing Activities:
Net cash flows used in investing activities	(1,088,406)	(950,347)	(952,258)
Cash Flows From Financing Activities:
Revolving credit facility borrowings (repayments), net	29,900	169,300	30,700
Long-term borrowings	1,358,096	558,000	1,816,345
Repayment of long-term debt	(910,000)	(179,500)	(1,411,345)
Issuance of common stock	198,177	0	0
Dividends paid	(126,705)	(119,839)	(112,972)
Debt issuance costs and other, net	(9,836)	(5,564)	(6,306)
Net cash flows from financing activities	537,100	386,037	357,561
Change in Cash, Cash Equivalents, and Restricted Cash	(135)	2,974	(46,824)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	4,078	1,104	47,928
Cash, Cash Equivalents, and Restricted Cash at End of Year	3,943	4,078	1,104
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	155,273	118,485	91,276
Income taxes paid (refunded), net	1,505	(1,011)	1,042
PNM Resources
Cash Flows From Operating Activities:
Net Cash Flows From Operating Activities	(31,368)	(10,261)	(28,514)
Cash Flows From Investing Activities:
Utility plant additions	1,138	1,136	543
Investments in subsidiaries	(85,500)	(70,200)	(178,071)
Cash dividends from subsidiaries	0	153,500	60,000
Net cash flows used in investing activities	(84,362)	84,436	(117,528)
Cash Flows From Financing Activities:
Short-term borrowings (repayments) -affiliate, net	(5,300)	(700)	6,400
Revolving credit facility borrowings (repayments), net	59,900	(45,500)	42,900
Long-term borrowings	500,000	100,000	1,120,000
Repayment of long-term debt	(500,000)	0	(900,000)
Issuance of common stock	198,177	0	0
Awards of common stock	(9,646)	(7,980)	(10,130)
Dividends paid	(126,177)	(119,311)	(112,444)
Debt issuance costs and other, net	(1,221)	(686)	(673)
Net cash flows from financing activities	115,733	(74,177)	146,053
Change in Cash, Cash Equivalents, and Restricted Cash	3	(2)	11
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	61	63	52
Cash, Cash Equivalents, and Restricted Cash at End of Year	64	61	63
Supplemental Cash Flow Disclosures:
Interest paid, net of amounts capitalized	47,122	29,904	13,425
Income taxes paid (refunded), net	$ 350	$ (2,500)	$ 0