Lease Commitments - Narrative (Details) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Apr. 30, 2023 USD ($)	Jan. 31, 2023 USD ($)	Sep. 30, 2023 USD ($) batteryStorageAgreement MW	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) MW	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Nov. 18, 2022 lease	Apr. 02, 2021 lease	Jan. 15, 2016 lease	Jan. 15, 2015 lease
Operating Leased Assets [Line Items]
Proceeds from sale of productive assets					$ 32,654	$ 0
Reduction to inventories					16,657	6,630
Operating lease, payments to lessor upon occurrence of certain events			$ 13,500		13,500
Unamortized cost, right-of-way lease payments			56,700		56,700		$ 54,600
Operating lease, right-of-use asset, amortization expense			800	$ 900	2,600	2,900
Operating lease, right-of-use asset			185,989		185,989		55,982
Lessee, operating lease, unguaranteed residual value			25,900		25,900
Lease to be executed, fixed consideration			$ 961,000		$ 961,000
Lease to be executed, term of contract			20 years		20 years
Materials, Supplies, and Fuel Stock
Operating Leased Assets [Line Items]
Reduction to inventories					$ (5,300)
PNM
Operating Leased Assets [Line Items]
Number of leases under which lease term was extended | lease								5	5
Proceeds from sale of productive assets					32,654	0
Reduction to inventories					12,300	3,809
Operating lease, right-of-use asset			$ 183,889		183,889		52,556
Lessee, operating lease, unguaranteed residual value			13,200		13,200
PNM | Palo Verde Nuclear Generating Station, Unit 1 and 4 Leases
Operating Leased Assets [Line Items]
Number of leases, expiring | lease											4
Number of leases under which lease term was extended | lease											4
PNM | Palo Verde Nuclear Generating Station, Unit 2 Leases
Operating Leased Assets [Line Items]
Number of leases, expiring | lease										4
Number of leases under which lease term was extended | lease										1
Annual lease payments during renewal period					1,600
PNM | Navajo Nation
Operating Leased Assets [Line Items]
Annual lease payments					6,000
Right-of-way lease payments	$ 8,300
TNMP
Operating Leased Assets [Line Items]
Reduction to inventories					4,357	$ 2,821
Operating lease, right-of-use asset			2,099		2,099		$ 3,426
Lessee, operating lease, unguaranteed residual value			12,700		12,700
Equipment
Operating Leased Assets [Line Items]
Operating lease, residual value of leased asset			1,900		1,900
Equipment | PNM
Operating Leased Assets [Line Items]
Operating lease, residual value of leased asset			900		900
Equipment | TNMP
Operating Leased Assets [Line Items]
Operating lease, residual value of leased asset			$ 1,000		1,000
PNM Owned Assets
Operating Leased Assets [Line Items]
Proceeds from sale of productive assets		$ 33,700
Net Utility Plant
Operating Leased Assets [Line Items]
Proceeds from sale of productive assets					$ 28,400
Other
Operating Leased Assets [Line Items]
Number of battery storage agreements | batteryStorageAgreement			2
Operating lease, term of contract			20 years		20 years
Operating lease, right-of-use asset			$ 138,700		$ 138,700
Other | PNM
Operating Leased Assets [Line Items]
Number of megawatts in battery storage facilities (in megawatts) | MW			170		170