Property, Plant and Equipment, Net Property, Plant and Equipment, Net - NPC (Details) - Nevada Power Company [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Net, Excluding Construction Work In Progress	$ 6,534	$ 6,559
Public Utilities, Property, Plant and Equipment, Construction Work in Progress	217	142
Property, plant and equipment, net	6,751	6,701
Regulated Operation [Member]
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Generation or Processing	3,691	3,690
Public Utilities, Property, Plant and Equipment, Transmission	1,465	1,468
Public Utilities, Property, Plant and Equipment, Distribution	3,803	3,771
Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment	798	791
Public Utilities, Property, Plant and Equipment, Plant in Service, Excluding Construction Work In Progress	9,757	9,720
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	3,224	3,162
Public Utilities, Property, Plant and Equipment, Net, Excluding Construction Work In Progress	$ 6,533	6,558
Regulated Operation [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Generation, Useful Life	30 years
Public Utilities, Property, Plant and Equipment, Transmission, Useful Life	45 years
Public Utilities, Property, Plant and Equipment, Distribution, Useful Life	20 years
Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Useful Life	5 years
Regulated Operation [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Generation, Useful Life	55 years
Public Utilities, Property, Plant and Equipment, Transmission, Useful Life	70 years
Public Utilities, Property, Plant and Equipment, Distribution, Useful Life	65 years
Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Useful Life	65 years
Unregulated Operation [Member]
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Net, Excluding Construction Work In Progress	$ 1	$ 1
Unregulated Operation [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Other Property Plant and Equipment, Useful Life	45 years