Income Taxes (Narrative) (Details) - USD ($) $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
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| Income Taxes [Abstract] | ||||
| Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate | 21.00% | 21.00% | 21.00% | 35.00% |
| Additional Income Tax Expense (Benefit) Recognized due to Tax Reform | $ 37 | |||
| Investment Tax Credit | $ 94 | $ 59 | 90 | |
| Tax Adjustments, Settlements, and Unusual Provisions | 133 | 131 | 137 | |
| Taxable Temporary Differences That Will Offset Amount Of Gross Deferred Tax Asset | 1,200 | |||
| Deferred Tax Assets, Net of Valuation Allowance | 785 | 461 | ||
| Deferred Tax Assets, Valuation Allowance | (31) | (32) | ||
| Decrease in Unrecognized Tax Benefits is Reasonably Possible | 4 | |||
| Unrecognized Tax Benefits that Would Impact Effective Tax Rate | 9 | 34 | $ 10 | |
| State net operating carryforwards, net of federal tax effect | $ 58 | $ 50 | ||
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- Definition Additional Income Tax Expense Recognized due to Tax Reform No definition available.
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- Definition Income Taxes [Abstract] No definition available.
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- Definition Taxable Temporary Differences That Will Offset Amount Of Gross Deferred Tax Asset No definition available.
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- Definition Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible state and local operating loss carryforwards. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The amount deducted from an entities' taxes, reflecting a percentage of an amount invested in certain assets spread over the useful life of those assets; includes deferred investment tax credits. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of increase (decrease) to previously recorded tax expense. Includes, but is not limited to, significant settlements of income tax disputes, and unusual tax positions or infrequent actions taken by the entity, including tax assessment reversal, and IRS tax settlement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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