XML 83 R52.htm IDEA: XBRL DOCUMENT v3.22.1
Summary of Significant Accounting Policies Depreciation (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Mar. 31, 2022
Dec. 31, 2021
Mar. 31, 2021
Mar. 31, 2022
Mar. 31, 2021
Property, Plant and Equipment [Line Items]          
Depreciation expense $ 455   $ 346 $ 908 $ 691
Increase due to new depreciation rates          
Property, Plant and Equipment [Line Items]          
Depreciation expense       $ 197  
Nuclear Plant          
Property, Plant and Equipment [Line Items]          
Public utilities, property, plant and equipment, disclosure of composite depreciation rate for plants of service   2.38%   2.72%  
Fossil Fuel Plant          
Property, Plant and Equipment [Line Items]          
Public utilities, property, plant and equipment, disclosure of composite depreciation rate for plants of service   1.95%   3.98%  
Hydro Plant          
Property, Plant and Equipment [Line Items]          
Public utilities, property, plant and equipment, disclosure of composite depreciation rate for plants of service   1.60%   1.95%  
Natural Gas Processing Plant          
Property, Plant and Equipment [Line Items]          
Public utilities, property, plant and equipment, disclosure of composite depreciation rate for plants of service   2.98%   3.45%  
Electric Transmission          
Property, Plant and Equipment [Line Items]          
Public utilities, property, plant and equipment, disclosure of composite depreciation rate for plants of service   1.34%   1.45%  
Other Plant in Service          
Property, Plant and Equipment [Line Items]          
Public utilities, property, plant and equipment, disclosure of composite depreciation rate for plants of service   7.12%   3.21%