Selected Balance Sheet Data, 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		$ 68,669	$ 65,464
Less accumulated depreciation and amortization		(18,363)	(17,502)
Property, plant and equipment, net		50,613	48,253
Electric plant
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		51,377	49,639
Natural gas plant
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		9,005	8,514
Common and other property
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		3,227	2,970
Plant to be retired
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	[1]	2,109	2,217
Construction work in progress
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		2,951	2,124
Nuclear fuel
Public Utility, Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		3,282	3,183
Less accumulated depreciation and amortization		$ (2,975)	$ (2,892)

[1] Amounts include Sherco Units 1, 2 and 3 and A.S. King for NSP-Minnesota; 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 for PSCo; and Tolk and coal generation assets at Harrington pending facility gas conversion for SPS. Amounts are presented net of accumulated depreciation.