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The difference in basis, attributable to different capitalization of costs, depreciation, or amortization methodologies, will increase future taxable income when such basis difference is realized. Capital assets include but are not limited to assets such as land, real estate, leasehold improvements, machinery and equipment and furniture and fixtures.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 43 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 11 -Subparagraph d, e, f falsefalsePlant-related basis differences6false0us-gaap_DeferredTaxLiabilitiesRegulatoryAssetsAndLiabilitiesus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse-1074133000-1074133falsefalsefalsefalsefalse2truefalsefalse-1147710000-1147710falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount as of the balance sheet date of the estimated future tax effects arising from differences in accounting under GAAP and tax returns for assets and liabilities established under GAAP pertaining to rate-setting.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 11, 43 falsefalseNet regulatory assets/(liabilities)7false0etr_DeferredTaxLiabilitiesPowerPurchaseAgreementsetrfalsecreditinstantDeferred Tax Liabilities, Power Purchase Agreements.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse-265429000-265429falsefalsefalsefalsefalse2truefalsefalse-862322000-862322falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryDeferred Tax Liabilities, Power Purchase Agreements.No authoritative reference available.falsefalsePower purchase agreements8false0etr_DeferredTaxLiabilitiesNuclearDecommissioningTrustsetrfalsecreditinstantDeferred Tax Liabilities, Nuclear Decommissioning Trusts.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse-439481000-439481falsefalsefalsefalsefalse2truefalsefalse-855608000-855608falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryDeferred Tax Liabilities, Nuclear Decommissioning Trusts.No authoritative reference available.falsefalseNuclear decommissioning trusts9false0us-gaap_DeferredTaxLiabilitiesOtherus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse-679302000-679302falsefalsefalsefalsefalse2truefalsefalse-456053000-456053falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cumulative amount of the estimated future tax effects attributable to other temporary differences not otherwise specified in this taxonomy that were expensed for tax purposes but capitalized in conformity with generally accepted accounting principles, or which were recognized as revenue under GAAP but not for tax purposes, which will reverse in future periods.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 43 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 11 -Subparagraph a, d, e truefalseOther10false0us-gaap_DeferredTaxLiabilitiesus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse-8406105000-8406105falsefalsefalsefalsefalse2truefalsefalse-8841788000-8841788falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cumulative amount of all deferred tax liabilities, which result from applying the applicable tax rate to net taxable temporary differences pertaining to each jurisdiction to which the entity is obligated to pay income tax. A taxable temporary difference is a difference between the tax basis and the carrying amount of an asset or liability in the financial statements prepared in accordance with generally accepted accounting principles that will result in taxable amounts in one or more future periods.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 42, 43 truefalseTotal11true0us-gaap_ComponentsOfDeferredTaxAssetsAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseDeferred tax assets:12false0us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsus-gaaptruedebitinstantNo definition 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amount of the estimated future tax deductions arising from pension costs, which can only be deducted for tax purposes when actual costs are incurred, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 43 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 11 -Subparagraph b falsefalsePension and other post-employment benefits14false0us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsRestructuringChargesus-gaaptruedebitinstantNo definition 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the tax returns in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 43, 289 falsefalseNet operating loss carryforwards21false0us-gaap_DeferredTaxAssetsCapitalLossCarryforwardsus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse5660200056602falsefalsefalsefalsefalse2truefalsefalse4578700045787falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe tax effect as of the balance sheet date of the amount of future tax deductions arising from capital losses in excess of statutory limitations in historical filings, and which can only be utilized if sufficient tax-basis income is generated in future periods and providing tax laws continue to allow such utilization.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 43 falsefalseCapital losses22false0us-gaap_DeferredTaxAssetsOtherus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse1900900019009falsefalsefalsefalsefalse2truefalsefalse160264000160264falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe tax effect as of the balance sheet date of the amount of estimated future tax deductions arising from other temporary differences not otherwise specified in the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 43 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A temporary difference is a difference between the tax basis of an asset or liability and its carrying amount in the financial statements prepared in accordance with generally accepted accounting principles that will reverse in ensuing periods. In a classified statement of financial position, an enterprise shall separate deferred tax liabilities and assets into a current amount and a noncurrent amount. Deferred tax liabilities and assets shall be classified as current or noncurrent based on the classification of the related asset or liability for financial reporting. A deferred tax liability or asset that is not related to an asset or liability for financial reporting, including deferred tax assets related to carryforwards, shall be classified according to the expected reversal date of the temporary difference.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 41, 42, 43 truefalseNoncurrent accrued taxes (including unrecognized tax benefits)26false0us-gaap_DeferredTaxAssetsLiabilitiesNetus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse-8559958000-8559958falsetruefalsefalsefalse2truefalsefalse-7711382000-7711382falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryFor entities that net deferred tax assets and tax liabilities, represents the unclassified net amount of deferred tax assets and liabilities as of the balance sheet date, which result from applying the applicable enacted tax rate to net temporary differences and carryforwards pertaining to assets or liabilities. 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