Commitments and Contingencies - NPC - Legal (Details) - Nevada Power Company [Member] - MW	3 Months Ended	12 Months Ended		36 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2017	Dec. 31, 2016
536 Megawatts of Renewable Energy [Member]
Loss Contingencies [Line Items]
New Generation Capacity				536
200 Megawatts of Solar Renewable Energy [Member]
Loss Contingencies [Line Items]
New Generation Capacity				200
15 Megawatts of Solar Renewable Energy [Member]
Loss Contingencies [Line Items]
New Generation Capacity				15
35 Megawatts of Renewable Energy [Member]
Loss Contingencies [Line Items]
New Generation Capacity		35
255 Megawatts of Coal Energy [Member]
Loss Contingencies [Line Items]
Coal-Fired Power Plant Capacity	255	255
557 Megawatts of Coal Energy [Member]
Loss Contingencies [Line Items]
Coal-Fired Power Plant Capacity			557