2.2.0.7 false CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $) 001000 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) true false In Thousands, except Share data false false 1 USD false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 2 USD false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 3 USD false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 4 USD false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ 2 Income Statement [Abstract] 0 us-gaap_IncomeStatementAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 3 OPERATING REVENUES 1 us-gaap_RegulatedOperatingRevenue us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 true true false false 785361000 785361 false false false 2 true true false false 838641000 838641 false false false 3 true true false false 1502330000 1502330 false false false 4 true true false false 1593908000 1593908 false false false xbrli:monetaryItemType monetary The total amount of regulated operating revenues recognized during the period. No authoritative reference available. true 4 OPERATING EXPENSES: 1 us-gaap_OperatingExpensesAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 5 Fuel for power generation 2 us-gaap_ElectricProductionExpense us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 181662000 181662 false false false 2 false true false false 204285000 204285 false false false 3 false true false false 403281000 403281 false false false 4 false true false false 434389000 434389 false false false xbrli:monetaryItemType monetary Cost incurred directly related to electricity produced and sold during the reporting period. 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No authoritative reference available. false 8 Deferred energy 2 nve_DeferralOfEnergyCostElectricNet nve false debit duration Represent the difference between actual fuel and purchased power costs incurred during the period and amounts recoverable... false false false false false false false false false false false terselabel false 1 false true false false 54933000 54933 false false false 2 false true false false 93577000 93577 false false false 3 false true false false 72499000 72499 false false false 4 false true false false 139212000 139212 false false false xbrli:monetaryItemType monetary Represent the difference between actual fuel and purchased power costs incurred during the period and amounts recoverable through currents rates. Also includes the current amortization of fuel and purchased power costs previously deferred. No authoritative reference available. false 9 Other operating expenses 2 us-gaap_OtherCostAndExpenseOperating us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 104066000 104066 false false false 2 false true false false 109886000 109886 false false false 3 false true false false 213172000 213172 false false false 4 false true false false 224563000 224563 false false false xbrli:monetaryItemType monetary The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 3 -Article 5 false 10 Maintenance 2 us-gaap_UtilitiesOperatingExpenseMaintenance us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 28860000 28860 false false false 2 false true false false 27632000 27632 false false false 3 false true false false 54589000 54589 false false false 4 false true false false 62032000 62032 false false false xbrli:monetaryItemType monetary Discloses the amount of operating expense for the period for routine plant maintenance and repairs. 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No authoritative reference available. false 13 Total Operating Expenses 2 us-gaap_CostsAndExpenses us-gaap true debit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 660631000 660631 false false false 2 false true false false 744342000 744342 false false false 3 false true false false 1304694000 1304694 false false false 4 false true false false 1457512000 1457512 false false false xbrli:monetaryItemType monetary Total costs of sales and operating expenses for the period. 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No authoritative reference available. false 17 Interest income (expense) on regulatory items 2 nve_InterestIncomeExpenseOnRegulatoryItems nve false credit duration Interest income or expense on regulatory items; including carrying charges on assets and interest accrued on deferred energy... false false false false false false false false false false false terselabel false 1 false true false false -2997000 -2997 false false false 2 false true false false -254000 -254 false false false 3 false true false false -5068000 -5068 false false false 4 false true false false 926000 926 false false false xbrli:monetaryItemType monetary Interest income or expense on regulatory items; including carrying charges on assets and interest accrued on deferred energy balance No authoritative reference available. false 18 AFUDC-equity 2 nve_AllowanceForEquityFundsUsedDuringConstruction nve false credit duration Total increase in earnings in the period representing the cost of equity (rate of return) used to finance construction of... false false false false false false false false false false false terselabel false 1 false true false false 7138000 7138 false false false 2 false true false false 8548000 8548 false false false 3 false true false false 13091000 13091 false false false 4 false true false false 14766000 14766 false false false xbrli:monetaryItemType monetary Total increase in earnings in the period representing the cost of equity (rate of return) used to finance construction of regulated assets, which is expected to be recovered through rate adjustments. 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