Lease Commitments - Narrative (Details) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Apr. 02, 2021 lease	Jan. 15, 2016 lease	Jan. 15, 2015 lease
Lessee, Lease, Description [Line Items]
Unamortized cost of prepaid right-of-way agreements		$ 54.6	$ 53.4
Amortization of prepaid right-of-way agreements		3.8	$ 3.7	$ 4.4
Lessee, operating lease, unguaranteed residual value		24.2
Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Number of leases under which lease term was extended | lease					5
Lessee, operating lease, unguaranteed residual value		11.3
Texas-New Mexico Power Company
Lessee, Lease, Description [Line Items]
Lessee, operating lease, unguaranteed residual value		12.9
Palo Verde Nuclear Generating Station, Units 1 And 4 | Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Number of leases expiring | lease							4
Number of leases under which lease term was extended | lease							4
Annual lease payments during renewal period		16.5
Palo Verde Nuclear Generating Station, Unit 2 | Public Service Company of New Mexico
Lessee, Lease, Description [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		1.6
Palo Verde Nuclear Generating Station | Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Loss contingency, range of possible loss, portion not accrued		14.1
Navajo Nation | Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Right-of-way lease, annual payments		6.0
Right-of-way lease, payments		7.9
PNM Owned Assets | Subsequent Event
Lessee, Lease, Description [Line Items]
Proceeds from sale of assets	$ 17.7
Nuclear Fuel | Subsequent Event
Lessee, Lease, Description [Line Items]
Proceeds from sale of assets	$ 17.3
Equipment
Lessee, Lease, Description [Line Items]
Operating lease, residual value of leased asset		2.2
Equipment | Public Service Company of New Mexico
Lessee, Lease, Description [Line Items]
Operating lease, residual value of leased asset		1.0
Equipment | Texas-New Mexico Power Company
Lessee, Lease, Description [Line Items]
Operating lease, residual value of leased asset		$ 1.2