Selected Balance Sheet Data Balance Sheet Related Disclosures, Property, Plant and Equipment (Details) - USD ($) $ in Millions		Sep. 30, 2023	Dec. 31, 2022
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 26,666	$ 25,317
Less accumulated depreciation		(6,013)	(5,665)
Property, plant and equipment, net		20,653	19,652
Electric plant
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		16,343	15,771
Natural gas plant
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		6,293	5,949
Common and other property
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		1,500	1,415
Plant to be retired
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	[1]	1,242	1,305
Construction work in progress
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 1,288	$ 877

[1] Amounts include Comanche Units 2 and 3, Craig Units 1 and 2, Hayden Units 1 and 2 and coal generation assets at Pawnee pending facility gas conversion. Amounts are presented net of accumulated depreciation.