Regulatory and Rate Matters (Tables)

6 Months Ended

Jun. 30, 2019

Regulated Operations [Abstract]

Schedule of Rate Increases for Transmission Costs

The following sets forth TNMP’s recent interim transmission cost rate increases:

Effective Date	Approved Increase in Rate Base	Annual Increase in Revenue
	(In millions)
March 14, 2017	30.2	4.8
September 13, 2017	27.5	4.7
March 27, 2018	32.0	0.6
March 21, 2019	111.8	14.3