Property Plant and Equipment (Details) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment		$ 23,728	$ 22,896
Accumulated depreciation and amortization		7,606	7,898
Property, Plant and Equipment, Net		16,430	15,308
Electric plant
Property, Plant and Equipment [Line Items]
Property, plant and equipment		19,154	18,948
Natural gas plant
Property, Plant and Equipment [Line Items]
Property, plant and equipment		1,864	1,707
Common and other property
Property, Plant and Equipment [Line Items]
Property, plant and equipment		1,007	955
Plant to be Retired [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	[1]	719	136
CWIP
Property, Plant and Equipment [Line Items]
Property, plant and equipment		984	1,150
Nuclear fuel
Property, Plant and Equipment [Line Items]
Property, plant and equipment		3,081	2,970
Accumulated depreciation and amortization		$ 2,773	$ 2,660

[1] Includes regulator-approved retirements of Sherco Units 1, 2 and 3 and A.S. King.