Pension and Other Postretirement Benefits - Assumed Health Care Cost Trend Rates and Impact of a One-Percentage-Point Change in Assumed Health Care Cost Trend Rates (Details) - Public Service Company of New Mexico - Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Health care cost trend rate assumed for next year	6.25%	6.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.75%	4.75%
Year that the rate reaches the ultimate trend rate	2029	2027