2.2.0.25falsefalse0120 - Statement - Condensed Consolidated Statements of Operations (Unaudited)truefalseIn Thousands, except Per Share datafalse1falsefalseUSDfalsefalse1/1/2011 - 3/31/2011 USD ($) / shares USD ($) $Jan-01-2011_Mar-31-2011http://www.sec.gov/CIK0001317630duration2011-01-01T00:00:002011-03-31T00:00:00USDEPSDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2falsefalseUSDfalsefalse1/1/2010 - 3/31/2010 USD ($) USD ($) / shares $ThreeMonthsEnded_31Mar2010http://www.sec.gov/CIK0001317630duration2010-01-01T00:00:002010-03-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDEPSDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2true0us-gaap_IncomeStatementAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseCondensed Consolidated Statements of Operations [Abstract]3false0us-gaap_ElectricUtilityRevenueus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse179386000179386falsetruefalsefalsefalse2truefalsefalse161288000161288falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe aggregate revenue, whether regulated or unregulated, derived from the generation, transmission and distribution of electricity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 falsefalseOPERATING REVENUES4true0us-gaap_CostsAndExpensesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseOPERATING EXPENSES5false0us-gaap_CostOfGoodsSoldElectricus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse2628400026284falsefalsefalsefalsefalse2truefalsefalse2372900023729falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryTotal costs related to electricity produced and sold during the reporting period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 2 -Article 5 falsefalseOperation and maintenance6false0us-gaap_GeneralAndAdministrativeExpenseus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse1658000016580falsefalsefalsefalsefalse2truefalsefalse1778100017781falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.No authoritative reference available.falsefalseGeneral and administrative7false0us-gaap_DepreciationAndAmortizationus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse2308800023088falsefalsefalsefalsefalse2truefalsefalse2211500022115falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 falsefalseDepreciation and amortization8false0us-gaap_TaxesOtherus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse1360800013608falsefalsefalsefalsefalse2truefalsefalse1230800012308falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryTaxes, excluding payroll, income and excise taxes, if not included elsewhere, that could include production, real and personal property, and other selling and distribution-related taxes.No authoritative reference available.falsefalseTaxes other than income taxes9false0itc_OtherOperatingIncomeAndExpenseNetitcfalsedebitdurationThe net amount of other operating income and expense.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse-149000-149falsefalsefalsefalsefalse2truefalsefalse70007falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net amount of other operating income and expense.No authoritative reference available.truefalseOther operating income and expense - net10false0us-gaap_OperatingExpensesus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse7941100079411falsefalsefalsefalsefalse2truefalsefalse7594000075940falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryGenerally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.No authoritative reference available.truefalseTotal operating expenses11false0us-gaap_OperatingIncomeLossus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse9997500099975falsefalsefalsefalsefalse2truefalsefalse8534800085348falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net result for the period of deducting operating expenses from operating revenues.No authoritative reference available.falsefalseOPERATING INCOME12true0us-gaap_OtherNonoperatingIncomeExpenseAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseOTHER EXPENSES (INCOME)13false0us-gaap_InterestExpenseus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse3627700036277falsefalsefalsefalsefalse2truefalsefalse3502900035029falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cost of borrowed funds accounted for as interest that was charged against earnings during the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 34 -Paragraph 21 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher OTS -Name Federal Regulation (FR) -Number Title 12 -Chapter V -Section 563c.102 -Paragraph 9 -Subsection II Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 9 -Article 9 falsefalseInterest expense14false0itc_AllowanceForEquityFundsUsedDuringConstructionitcfalsecreditdurationIncludes the net cost for the period of construction of equity funds used for construction of regulated assets, which is...falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-3510000-3510falsefalsefalsefalsefalse2truefalsefalse-3143000-3143falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryIncludes the net cost for the period of construction of equity funds used for construction of regulated assets, which is expected to be recovered through rates.No authoritative reference available.falsefalseAllowance for equity funds used during construction15false0us-gaap_OtherNonoperatingIncomeus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-275000-275falsefalsefalsefalsefalse2truefalsefalse-626000-626falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe aggregate amount of other income amounts resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) profits on securities (net of losses), and (d) miscellaneous other income items.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-BRD -Chapter 4 -Paragraph 80 -Subparagraph Exhibit 4-4 -IssueDate 2006-05-01 falsefalseOther income16false0us-gaap_OtherNonoperatingExpenseus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse722000722falsefalsefalsefalsefalse2truefalsefalse384000384falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAny other expense items resulting from secondary business-related activities, excluding those considered part of the normal operations of the business that have not been previously categorized.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 truefalseOther expense17false0us-gaap_NonoperatingIncomeExpenseus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegatedtotal1truefalsefalse3321400033214falsefalsefalsefalsefalse2truefalsefalse3164400031644falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe aggregate amount of income (expense) from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Article 5 truefalseTotal other expenses (income)18false0us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse6676100066761falsefalsefalsefalsefalse2truefalsefalse5370400053704falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetarySum of operating profit and nonoperating income (expense) before income (loss) from equity method investments, income taxes, extraordinary items, cumulative effects of changes in accounting principles, and noncontrolling interest.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Subparagraph 1(i) -Article 4 falsefalseINCOME BEFORE INCOME TAXES19false0us-gaap_IncomeTaxExpenseBenefitus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse2475900024759falsefalsefalsefalsefalse2truefalsefalse1950000019500falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe sum of the current income tax expense (benefit) and the deferred income tax expense (benefit) pertaining to continuing operations.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Article 4 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 45 -Subparagraph a, b truefalseINCOME TAX PROVISION20false0us-gaap_NetIncomeLossus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse4200200042002falsetruefalsefalsefalse2truefalsefalse3420400034204falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent. If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 19 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph d Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A7 -Appendix A Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 20 -Article 9 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 10, 15 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 87-21 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28, 29, 30 truefalseNET INCOME21false0us-gaap_EarningsPerShareBasicus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse0.830.83falsetruefalsefalsefalse2truefalsefalse0.680.68falsetruefalsefalsefalseEPSus-types:perShareItemTypedecimalThe amount of net income or loss for the period per each share of common stock outstanding during the reporting period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 36, 37, 38 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 falsetrueBasic earnings per common share (Note 6)22false0us-gaap_EarningsPerShareDilutedus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse0.810.81falsetruefalsefalsefalse2truefalsefalse0.670.67falsetruefalsefalsefalseEPSus-types:perShareItemTypedecimalThe amount of net income or loss for the period per each share of common stock and dilutive common stock equivalents outstanding during the reporting period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 11, 12, 36 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 falsetrueDiluted earnings per common share (Note 6)23false0us-gaap_CommonStockDividendsPerShareDeclaredus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse0.3350.335falsetruefalsefalsefalse2truefalsefalse0.3200.320falsetruefalsefalsefalseEPSus-types:perShareItemTypedecimalAggregate dividends declared during the period for each share of common stock outstanding.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 falsetrueDividends declared per common share222Condensed Consolidated Statements of Operations (Unaudited) (USD $)ThousandsUnKnownNoRoundingUnKnownfalsetrue