Regulatory Environment - MGU and UMERC (Details) - UMERC $ in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2016 MW	Dec. 31, 2019 USD ($)
Public Utilities, General Disclosures [Line Items]
Electric Power Purchase Agreement Term with Tilden	20 years
Capacity of UMERC Generation | MW	180
Cost to Construct UMERC Generation		$ 242
Cost to Construct UMERC Generation with AFUDC		$ 255
Cost of Rice Units to be recovered from Utility Customers		50.00%
Cost of Rice Units to be recovered from Tilden		50.00%