Regulatory and Rate Matters - TNMP Narrative (Details) - Texas-New Mexico Power Company - USD ($) $ in Millions	Jan. 23, 2023	Jul. 18, 2022	Apr. 05, 2022	Jul. 01, 2021	Apr. 05, 2021	Sep. 24, 2022	May 27, 2022
Public Utilities, General Disclosures [Line Items]
Energy efficiency cost recovery factor, requested change amount							$ 7.4
Energy efficiency cost recovery factor, requested performance bonus						$ 1.9	$ 1.9
Energy efficiency cost recovery factor, settlement amount						$ 7.3
Requested increase annual distribution revenue requirement		$ 6.8	$ 9.7	$ 13.5	$ 14.0
Incremental distribution investments					$ 104.5
Increase in rate base			$ 100.7
Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested increase annual distribution revenue requirement	$ 19.4
Incremental distribution investments	$ 150.5