Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2017

Related Party Transactions [Abstract]

Schedule of Related Party Transactions

The table below summarizes the nature and amount of related party transactions of PNMR, PNM and TNMP:    

	Year Ended December 31,
	2017		2016		2015
			(In thousands)
Services billings:
PNMR to PNM	$	97,914	$	94,606	$	90,827
PNMR to TNMP	31,095		28,907		28,109
PNM to TNMP	382		427		554
TNMP to PNMR	141		66		41
TNMP to PNM	154		172		—
Interest billings:
PNMR to PNM	21		11		54
PNM to PNMR	220		150		110
PNMR to TNMP	133		132		276
Income tax sharing payments:
PNMR to TNMP	—		—		—
PNMR to PNM	23,391		—		1,450
TNMP to PNMR	20,686		—		—