Regulatory and Rate Matters - SJGS Abandonment Application (Details) $ in Thousands								3 Months Ended	12 Months Ended
	Dec. 15, 2023 USD ($)	Sep. 21, 2023 USD ($)	Aug. 18, 2023 USD ($)	Jul. 29, 2022 USD ($)	Jun. 17, 2022 USD ($)	Jul. 10, 2019 proceeding	Jul. 01, 2019 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Nov. 15, 2023 USD ($)	Feb. 21, 2020 USD ($)
Public Utilities, General Disclosures [Line Items]
Operating Revenues									$ 1,939,198	$ 2,249,555	$ 1,779,873
PNM
Public Utilities, General Disclosures [Line Items]
Regulatory assets								$ 911,723	911,723	782,274
Payments for legal settlements				$ 19,800
Proposed rate credits			$ 115,000
Rate credit period			1 year
Securitization bonds, weighted-average maximum rate			5.50%
Rate credits	$ 13,700
Regulatory liabilities								699,867	699,867	564,902
Operating Revenues									1,403,948	1,766,825	$ 1,362,020
PNM | Securitized Bonds | Senior Secured Notes, Energy Transition Bonds
Public Utilities, General Disclosures [Line Items]
Aggregate principal amount												$ 343,200
Debt, Weighted Average Interest Rate												5.50%
PNM | Securitized Bonds, 5.64% | Senior Secured Notes, Energy Transition Bonds
Public Utilities, General Disclosures [Line Items]
Aggregate principal amount												$ 175,000
Stated percentage												5.64%
PNMR and PNM | New Mexico Public Regulation Commission
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities		$ 128,700
Operating Revenues		$ (128,700)
Regulatory disallowance								3,300
Regulatory asset, reversal								3,300	3,300
San Juan Generating Station | PNM
Public Utilities, General Disclosures [Line Items]
Request issuance of energy transition bonds							$ 361,000
Forecasted undepreciated investment								283,000	283,000				$ 361,000
Plant decommissioning and coal mine reclamation costs								28,600	28,600
Upfront financing costs								$ 9,600	9,600
Severance costs									$ 20,000
Proceeds from securitization bonds							$ 19,800
Regulatory assets										$ 37,200
Number of proceedings | proceeding						2
San Juan Generation Station, Unit 1 | PNM
Public Utilities, General Disclosures [Line Items]
Annual rate credits					$ 21,100
San Juan Generating Station, Unit 4 | PNM
Public Utilities, General Disclosures [Line Items]
Annual rate credits					$ 98,300
Number of days to transfer payment					30 days