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v3.21.1

Exit Activities - Narrative (Details) - Retention Benefits - D.E. Karn Generating Complex - USD ($) $ in Millions | 3 Months Ended | 18 Months Ended
--- | --- | ---
Mar. 31, 2021 | Mar. 31, 2020 | Mar. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |
Expected cost | $ 35 |  | $ 35
Retention and severance costs | 0 | $ 4 | 16
Retention Incentive Program |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |
Regulatory asset | $ 2 |  | 2
Property, Plant and Equipment |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |
Costs incurred and capitalized |  |  | $ 3

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