Property, Plant and Equipment (Details) - USD ($) $ in Millions		Jun. 30, 2022	Dec. 31, 2021
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		$ 24,427	$ 23,728
Accumulated depreciation and amortization		(7,938)	(7,606)
Property, plant and equipment, net		16,751	16,430
Electric plant
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		19,826	19,154
Natural gas plant
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		1,940	1,864
Common and other property
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		1,083	1,007
Plant to be Retired (a)
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	[1]	682	719
Construction work in progress
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		896	984
Nuclear fuel
Public Utility, Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		3,096	3,081
Accumulated depreciation and amortization		$ (2,834)	$ (2,773)

[1] Amounts include regulator-approved retirements of Sherco Units 1, 2 and 3 and A.S. King and are reported net of accumulated depreciation.