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Summary of Significant Accounting Policies - Estimated Service Lives (Details) | 12 Months Ended
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Dec. 31, 2021
Equipment | Minimum | Electric Plant in Service |
Public Utility, Property, Plant and Equipment [Line Items] |
Production, useful life | 9 years
Transmission, useful life | 51 years
Distribution, useful life | 16 years
General, useful life | 5 years
Equipment | Minimum | Nonelectric Property, Plant and Equipment |
Public Utility, Property, Plant and Equipment [Line Items] |
Useful life | 2 years
Equipment | Maximum | Electric Plant in Service |
Public Utility, Property, Plant and Equipment [Line Items] |
Production, useful life | 83 years
Transmission, useful life | 75 years
Distribution, useful life | 70 years
General, useful life | 60 years
Equipment | Maximum | Nonelectric Property, Plant and Equipment |
Public Utility, Property, Plant and Equipment [Line Items] |
Useful life | 12 years
Buildings and Leasehold Improvements | Minimum | Nonelectric Property, Plant and Equipment |
Public Utility, Property, Plant and Equipment [Line Items] |
Useful life | 5 years
Buildings and Leasehold Improvements | Maximum | Nonelectric Property, Plant and Equipment |
Public Utility, Property, Plant and Equipment [Line Items] |
Useful life | 40 years

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- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
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- Definition Useful life of utility distribution assets owned by public utility, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Useful life of utility transmission equipment owned by public utility, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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