Lease Commitments - Schedule of Weighted Average Remaining Lease Terms and Discount Rates (Details)	Mar. 31, 2024
Weighted average remaining lease term (years):
Operating leases	16 years 5 months 15 days
Financing leases	3 years 4 months 6 days
Weighted average discount rate:
Operating leases	5.60%
Financing leases	4.72%
PNM
Weighted average remaining lease term (years):
Operating leases	16 years 7 months 2 days
Financing leases	3 years 8 months 1 day
Weighted average discount rate:
Operating leases	5.61%
Financing leases	4.65%
TNMP
Weighted average remaining lease term (years):
Operating leases	1 year 6 months 25 days
Financing leases	3 years 7 days
Weighted average discount rate:
Operating leases	4.22%
Financing leases	4.80%