Regulatory and Rate Matters - SJGS Abandonment Application, Fours Corners, PVNGS Leased Interest Abandonment Application, Summer Peak Resource Adequacy, COVID and Transportation Electrification Program (Details) $ in Thousands													1 Months Ended	3 Months Ended		9 Months Ended			12 Months Ended
	Oct. 25, 2023 MW batteryStorageAgreement	Sep. 21, 2023 USD ($)	Aug. 18, 2023 USD ($)	Jul. 18, 2023 MW	Jan. 30, 2023 MW	Nov. 18, 2022 lease MW	Oct. 03, 2022 USD ($)	Jul. 29, 2022 USD ($)	Jul. 19, 2022 MW	Jun. 17, 2022 USD ($)	Jan. 08, 2021 USD ($)	Nov. 01, 2020 USD ($)	Nov. 30, 2020 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($) MW	Sep. 30, 2023 USD ($)	Mar. 31, 2023 MW	Sep. 30, 2022 USD ($) MW	Dec. 31, 2019 USD ($) proceeding	Dec. 31, 2022 USD ($)	Apr. 02, 2021 lease MW	Dec. 31, 2020 USD ($)
Public Utilities, General Disclosures [Line Items]
Electric operating revenues														$ 505,851	$ 729,888	$ 1,527,084		$ 1,673,736
Regulatory disallowance														3,700
Decrease in undepreciated leasehold improvements														88,200		88,200
Increase in deferred regulatory assets														88,200		88,200
Regulatory assets														924,487		924,487				$ 846,686
Regulatory liabilities														764,360		764,360				755,202
Subsequent event
Public Utilities, General Disclosures [Line Items]
Number of battery storage agreements | batteryStorageAgreement	3
PNM
Public Utilities, General Disclosures [Line Items]
Payments for legal settlements								$ 19,800
Proposed rate credits			$ 115,000													115,000
Proposed rate credit payout period			1 year
Securitization bonds, weighted-average maximum rate			5.50%
Electric operating revenues														350,334	$ 597,337	1,118,741		$ 1,312,800
Regulatory disallowance																3,700
Number of leases under which lease term was extended | lease						5															5
Potential loss on rate change																28,800
Number of megawatts, peak during period (in megawatts) | MW				2,162					2,139
Grid modernization investment							$ 344,000
Grid modernization, initial term							6 years
Grid modernization term							11 years
Regulatory assets														846,107		846,107				763,941
Regulatory liabilities														551,747		551,747				556,989
PNM | Four Corners
Public Utilities, General Disclosures [Line Items]
Request issuance of energy transition bonds											$ 300,000
Forecasted undepreciated investment											272,000
Plant decommissioning and coal mine reclamation costs											4,600
Upfront financing costs											7,300
Proceeds from securitization bonds											$ 16,500
Payments for relief from obligations												$ 75,000	$ 15,000
Final payment for relief from obligations													$ 60,000
PNM | Four Corners | PNM
Public Utilities, General Disclosures [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners												13.00%
PNM | Deferred COVID-19 Costs | COVID-19
Public Utilities, General Disclosures [Line Items]
Regulatory assets														5,700		5,700				5,700
Regulatory liabilities														900		900				$ 900
PNM | Leased Interest Termination on January 15, 2023
Public Utilities, General Disclosures [Line Items]
Number of leases under which lease term was extended | lease																					4
PNM | Leased Interest Termination on January 15, 2023 | NMPRC
Public Utilities, General Disclosures [Line Items]
Solar generation capacity (in megawatts) | MW																					104
PNM | Leased Interest Termination on January 15, 2024 | NMPRC
Public Utilities, General Disclosures [Line Items]
Solar generation capacity (in megawatts) | MW																					10
PNM | Solar Agreement
Public Utilities, General Disclosures [Line Items]
Solar generation capacity (in megawatts) | MW															300			300
Number of megawatts available in purchase power agreement (in megawatts) | MW					100
PNM | Battery Storage Agreement
Public Utilities, General Disclosures [Line Items]
Solar generation capacity (in megawatts) | MW															300			300
Number of megawatts available in purchase power agreement (in megawatts) | MW					30
PNM | NM 2022 Rate Case
Public Utilities, General Disclosures [Line Items]
Megawatt repurchase | MW						64.1
PNM | Firm Power Purchases
Public Utilities, General Disclosures [Line Items]
Number of megawatts available in purchase power agreement (in megawatts) | MW																	420
PNM | Firm Capacity
Public Utilities, General Disclosures [Line Items]
Number of megawatts available in purchase power agreement (in megawatts) | MW																	40
PNM | Solar Agreement One | Subsequent event
Public Utilities, General Disclosures [Line Items]
Number of megawatts available in purchase power agreement (in megawatts) | MW	100
PNM | Solar Agreement Two | Subsequent event
Public Utilities, General Disclosures [Line Items]
Number of megawatts available in purchase power agreement (in megawatts) | MW	60
PNM | Battery Storage Agreement One | Subsequent event
Public Utilities, General Disclosures [Line Items]
Number of megawatts available in purchase power agreement (in megawatts) | MW	100
PNM | Battery Storage Agreement Two | Subsequent event
Public Utilities, General Disclosures [Line Items]
Number of megawatts available in purchase power agreement (in megawatts) | MW	100
PNM | Battery Storage Agreement Three | Subsequent event
Public Utilities, General Disclosures [Line Items]
Number of megawatts available in purchase power agreement (in megawatts) | MW	50
PNMR and PNM | New Mexico Public Regulation Commission+
Public Utilities, General Disclosures [Line Items]
Electric operating revenues		$ (115,000)
Regulatory liability														115,000		115,000
Regulatory asset, reversal														(2,300)		$ (2,300)
Regulatory disallowance														$ 2,300
San Juan Generating Station | PNM
Public Utilities, General Disclosures [Line Items]
Request issuance of energy transition bonds																			$ 361,000
Forecasted undepreciated investment																			283,000			$ 361,000
Plant decommissioning and coal mine reclamation costs																			28,600
Upfront financing costs																			9,600
Severance costs																			20,000
Proceeds from securitization bonds																			$ 19,800
Number of proceedings | proceeding																			2
Number of recommendations | proceeding																			1
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