Selected Balance Sheet Data Balance Sheet Related Disclosures, Property, Plant and Equipment, Net (Details) - USD ($) $ in Millions		Sep. 30, 2023	Dec. 31, 2022
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 11,099	$ 10,615
Accumulated depreciation		(2,674)	(2,486)
Property, plant and equipment, net		8,425	8,129
Electric plant
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		10,555	10,182
Plant to be Retired
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	[1]	251	266
Construction work in progress
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 293	$ 167

[1] Amounts include Tolk and coal generation assets at Harrington pending facility gas conversion. Amounts are reported net of accumulated depreciation.