Regulatory and Rate Matters - Schedule of Transmission Cost of Service Rates (Details) - TNMP - USD ($) $ in Millions							10 Months Ended	12 Months Ended
	Sep. 22, 2022	Mar. 25, 2022	Sep. 20, 2021	Mar. 12, 2021	Oct. 07, 2020	Mar. 27, 2020	Dec. 31, 2022	Feb. 28, 2022	Feb. 28, 2021
Energy efficiency costs
Public Utilities, General Disclosures [Line Items]
Aggregate Collection Amount							$ 7.2	$ 5.9	$ 5.9
Performance Bonus							$ 2.3	$ 1.0	$ 0.8
Transmission Cost of Service Rates
Public Utilities, General Disclosures [Line Items]
Approved Increase in Rate Base	$ 36.0	$ 95.6	$ 41.2	$ 112.6	$ 10.8	$ 59.2
Annual Increase in Revenue	$ 5.3	$ 14.2	$ 6.3	$ 14.1	$ 2.0	$ 7.8