2.2.0.7 false CONSOLIDATED BALANCE SHEETS (USD $) 00300 - Statement - CONSOLIDATED BALANCE SHEETS true false In Millions false false 1 USD false false Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit13 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Unit12 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 2 USD false false Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit13 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Unit12 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ 4 Current Assets: 2 us-gaap_AssetsCurrentAbstract 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 xbrli:stringItemType string No definition available. false 5 Cash and cash equivalents 3 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 true true false false 463600000 463.6 false false false 2 true true false false 286600000 286.6 false false false xbrli:monetaryItemType monetary Includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits should not be reported as cash and cash equivalents. 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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 3 -Subparagraph a, b -Article 5 false 8 Unbilled utility revenue 4 us-gaap_ReceivablesLongTermContractsOrPrograms us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 97800000 97.8 false false false 2 false true false false 116400000 116.4 false false false xbrli:monetaryItemType monetary Amount to be collected within one year of the balance sheet date (or one operating cycle, if longer) from customers in accordance with the contractual provisions of long-term contracts or programs including amounts billed and unbilled as of the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 3 -Subparagraph c -Article 5 false 9 Wholesale and other 4 us-gaap_OtherReceivables us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 41300000 41.3 false false false 2 false true false false 64400000 64.4 false false false xbrli:monetaryItemType monetary Carrying amounts due as of the balance sheet date from parties or arising from transactions not otherwise specified in the taxonomy. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 8 -Article 5 false 10 Allowance for uncollectible accounts 4 us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent us-gaap true credit instant No definition available. false false false false false false false false false false true negated false 1 false true false false -15500000 -15.5 false false false 2 false true false false -14000000 -14.0 false false false xbrli:monetaryItemType monetary A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 4 -Article 5 false 11 Materials and supplies 3 us-gaap_InventoryNet us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 109200000 109.2 false false false 2 false true false false 110600000 110.6 false false false xbrli:monetaryItemType monetary Carrying amount (lower of cost or market) as of the balance sheet date of inventories less all valuation and other allowances. Excludes noncurrent inventory balances (expected to remain on hand past one year or one operating cycle, if longer). No authoritative reference available. false 12 Fuel 3 us-gaap_EnergyRelatedInventory us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 140900000 140.9 false false false 2 false true false false 206400000 206.4 false false false xbrli:monetaryItemType monetary Carrying amount as of the balance sheet date of merchandise, goods, commodities, or supplies relating to a source of usable power held for future sale or future use in manufacturing or production process. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 6 -Subparagraph a -Article 5 false 13 Deferred income taxes 3 us-gaap_DeferredTaxAssetsNetCurrent us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 0 0 false false false 2 false true false false 81500000 81.5 false false false xbrli:monetaryItemType monetary The current portion of the aggregate tax effects as of the balance sheet date of all future tax deductions arising from temporary differences between tax basis and generally accepted accounting principles basis recognition of assets, liabilities, revenues and expenses, which can only be deducted for tax purposes when permitted under enacted tax laws; after deducting the allocated valuation allowance, if any, to reduce such amount to net realizable value. 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. An unrecognized tax benefit that is directly related to a position taken in a tax year that results in a net operating loss carryforward should be presented as a reduction of the related deferred tax asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 41, 42, 43 false 14 Prepaid taxes 3 us-gaap_PrepaidTaxes us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 56000000 56.0 false false false 2 false true false false 48400000 48.4 false false false xbrli:monetaryItemType monetary Carrying amount as of the balance sheet date of payments made in advance for income and other taxes, which will be charged against earnings within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Chapter 3 -Section A -Paragraph 4 false 15 Collateral deposits 3 us-gaap_DepositAssets us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 21500000 21.5 false false false 2 false true false false 20800000 20.8 false false false xbrli:monetaryItemType monetary The carrying amount of the asset transferred to a third party to serve as a deposit, which typically serves as security against failure by the transferor to perform under terms of an agreement. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 17 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 8 -Article 5 false 16 Derivative assets 3 us-gaap_DerivativeAssetsCurrent us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 45000000 45.0 false false false 2 false true false false 4600000 4.6 false false false xbrli:monetaryItemType monetary Fair values as of the balance sheet date for all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments and which are expected to be converted into cash or otherwise disposed of within a year or the normal operating cycle, if longer, net of the effects of master netting arrangements. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 4, 17 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 107 -Paragraph 10 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Chapter 3 -Section A -Paragraph 4 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FIN39-1 -Paragraph 10A, 10B false 17 Restricted funds 3 us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 14300000 14.3 false false false 2 false true false false 25900000 25.9 false false false xbrli:monetaryItemType monetary The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. For a classified balance sheet represents the current portion only (the noncurrent portion has a separate concept); there is a separate and distinct element for unclassified presentations. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 1 -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 4-8, 3 -IssueDate 2006-05-01 false 18 Regulatory assets 3 us-gaap_RegulatoryAssetsCurrent us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 114800000 114.8 false false false 2 false true false false 132700000 132.7 false false false xbrli:monetaryItemType monetary Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are expected to be recovered through revenue sources within one year or the normal operating cycle, if longer. Such costs are capitalized if they meet both of the following criteria: a. It is probable that future revenue in an amount at least equal to the capitalized cost will result from inclusion of that cost in allowable costs for rate-making purposes. b. Based on available evidence, the future revenue will be provided to permit recovery of the previously incurred cost rather than to provide for expected levels of similar future costs. If the revenue will be provided through an automatic rate-adjustment clause, this criterion requires that the regulator's intent clearly be to permit recovery of the previously incurred cost. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 71 -Paragraph 9, 10 false 19 Assets held for sale 3 us-gaap_AssetsHeldForSaleCurrent us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 0 0 false false false 2 false true false false 32400000 32.4 false false false xbrli:monetaryItemType monetary Current assets (normally turning over within one year or one business cycle if longer) that are held for sale apart from normal operations and anticipated to be sold within one year. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 144 -Paragraph 46 false 20 Other 3 us-gaap_OtherAssetsCurrent us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 76200000 76.2 false false false 2 false true false false 40400000 40.4 false false false xbrli:monetaryItemType monetary Aggregate carrying amount, as of the balance sheet date, of current assets not separately presented elsewhere in the balance sheet. Current assets are expected to be realized or consumed within one year (or the normal operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 8 -Article 5 false 21 Total current assets 3 us-gaap_AssetsCurrent us-gaap true debit instant No definition available. false false false false false false false false false false false totallabel false 1 false true false false 1400400000 1400.4 false false false 2 false true false false 1345300000 1345.3 false false false xbrli:monetaryItemType monetary Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 9 -Article 5 true 22 Property, Plant and Equipment: 2 us-gaap_PropertyPlantAndEquipmentNetAbstract 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 xbrli:stringItemType string No definition available. false 23 Generation 3 aye_PropertyPlantAndEquipmentGenerationOrProcessing aye false debit instant Period end amount of property, plant and equipment (PPE) related to generation or processing. false false false false false false false false false false false terselabel false 1 false true false false 7548600000 7548.6 false false false 2 false true false false 7469400000 7469.4 false false false xbrli:monetaryItemType monetary Period end amount of property, plant and equipment (PPE) related to generation or processing. No authoritative reference available. false 24 Transmission 3 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentTransmission us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 1408200000 1408.2 false false false 2 false true false false 1313200000 1313.2 false false false xbrli:monetaryItemType monetary Period end amount of property, plant and equipment (PPE) related to utility transmission owned by public utility. No authoritative reference available. false 25 Distribution 3 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentDistribution us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 3888500000 3888.5 false false false 2 false true false false 3784400000 3784.4 false false false xbrli:monetaryItemType monetary Period end amount of property, plant and equipment (PPE) related to utility distribution. No authoritative reference available. false 26 Other 3 us-gaap_PropertyPlantAndEquipmentOther us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 498700000 498.7 false false false 2 false true false false 440700000 440.7 false false false xbrli:monetaryItemType monetary This element represents capitalized assets classified as property, plant and equipment not otherwise defined in the taxonomy. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 false 27 Accumulated depreciation 3 us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment us-gaap true credit instant No definition available. false false false false false false false false false false true negated false 1 false true false false -5308000000 -5308.0 false false false 2 false true false false -5104900000 -5104.9 false false false xbrli:monetaryItemType monetary The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 -Subparagraph c Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 14 -Article 5 false 28 Subtotal 3 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet us-gaap true debit instant No definition available. false false false false false false false false false false false totallabel false 1 false true false false 8036000000 8036.0 false false false 2 false true false false 7902800000 7902.8 false false false xbrli:monetaryItemType monetary Period end amount of total net PPE No authoritative reference available. true 29 Construction work in progress 3 us-gaap_ConstructionInProgressGross us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 1104700000 1104.7 false false false 2 false true false false 800600000 800.6 false false false xbrli:monetaryItemType monetary Carrying amount at the balance sheet date of long-lived asset under construction that include construction costs to date on capital projects that have not been completed and assets being constructed that are not ready to be placed into service. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 false 30 Property, plant and equipment held for sale, net 3 us-gaap_AssetsHeldForSalePropertyPlantAndEquipment us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 0 0 false false false 2 false true false false 253700000 253.7 false false false xbrli:monetaryItemType monetary Property, plant and equipment that is held for sale apart from normal operations and anticipated to be sold in less than one year. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 144 -Paragraph 46 false 31 Total property, plant and equipment, net 3 us-gaap_PropertyPlantAndEquipmentNet us-gaap true debit instant No definition available. false false false false false false false false false false false totallabel false 1 false true false false 9140700000 9140.7 false false false 2 false true false false 8957100000 8957.1 false false false xbrli:monetaryItemType monetary Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, and production equipment. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 13 -Subparagraph a -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 12 -Paragraph 5 -Subparagraph b, c Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 7 true 32 Other Noncurrent Assets: 2 us-gaap_OtherAssetsNoncurrentAbstract 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 xbrli:stringItemType string No definition available. false 33 Regulatory assets 3 us-gaap_RegulatoryAssetsNoncurrent us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 730900000 730.9 false false false 2 false true false false 717300000 717.3 false false false xbrli:monetaryItemType monetary Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 71 -Paragraph 9, 10 false 34 Goodwill 3 us-gaap_Goodwill us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 367300000 367.3 false false false 2 false true false false 367300000 367.3 false false false xbrli:monetaryItemType monetary Carrying amount as of the balance sheet date, which is the cumulative amount paid, adjusted for any amortization recognized prior to adoption of FAS 142 and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 142 -Paragraph 43 false 35 Restricted funds 3 us-gaap_RestrictedCashAndCashEquivalentsNoncurrent us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 31600000 31.6 false false false 2 false true false false 60200000 60.2 false false false xbrli:monetaryItemType monetary Cash and equivalents whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 1 -Article 5 false 36 Investments in unconsolidated affiliates 3 us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false true false false 48900000 48.9 false false false 2 false true false false 26700000 26.7 false false false xbrli:monetaryItemType monetary Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable form a party that is affiliated with the reporting entity by means of direct or indirect ownership. No authoritative reference available. false 37 Derivative assets 3 us-gaap_DerivativeAssetsNoncurrent us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 22600000 22.6 false false false 2 false true false false 0 0 false false false xbrli:monetaryItemType monetary Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments which are expected to exist longer than one year or beyond the normal operating cycle, if longer, net of the effects of master netting arrangements. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 4, 17 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 107 -Paragraph 10 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Chapter 3 -Section A -Paragraph 4 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FIN39-1 -Paragraph 10A, 10B false 38 Other 3 us-gaap_OtherAssetsNoncurrent us-gaap true debit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 99700000 99.7 false false false 2 false true false false 115200000 115.2 false false false xbrli:monetaryItemType monetary Aggregate carrying amount, as of the balance sheet date, of noncurrent assets not separately disclosed in the balance sheet due to materiality considerations. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 17 -Article 5 false 39 Total other noncurrent assets 3 aye_TotalOtherAssets aye false debit instant Total Other Assets false false false false false false false false false false false totallabel false 1 false true false false 1301000000 1301.0 false false false 2 false true false false 1286700000 1286.7 false false false xbrli:monetaryItemType monetary Total Other Assets No authoritative reference available. true 40 Total Assets 2 us-gaap_Assets us-gaap true debit instant No definition available. false false false false false false false false false false false totallabel false 1 false true false false 11842100000 11842.1 false false false 2 false true false false 11589100000 11589.1 false false false xbrli:monetaryItemType monetary Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Concepts (CON) -Number 6 -Paragraph 25 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 18 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 7 true 42 Current Liabilities: 2 us-gaap_LiabilitiesCurrentAbstract 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 xbrli:stringItemType string No definition available. false 43 Long-term debt due within one year 3 us-gaap_LongTermDebtCurrent us-gaap true credit instant No definition available. false false false false false false false false false false false false 1 false true false false 15500000 15.5 false false false 2 false true false false 140800000 140.8 false false false xbrli:monetaryItemType monetary Total of the portions of the carrying amounts as of the balance sheet date of long-term debt, which may include notes payable, bonds payable, debentures, mortgage loans, and commercial paper, which are scheduled to be repaid within one year or the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19 -Article 5 false 44 Accounts payable 3 us-gaap_AccountsPayableCurrent us-gaap true credit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 360000000 360.0 false false false 2 false true false false 411400000 411.4 false false false xbrli:monetaryItemType monetary Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19 -Subparagraph a -Article 5 false 45 Accrued taxes 3 us-gaap_TaxesPayableCurrent us-gaap true credit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 78600000 78.6 false false false 2 false true false false 87300000 87.3 false false false xbrli:monetaryItemType monetary Carrying value as of the balance sheet date of obligations incurred and payable for statutory income, sales, use, payroll, excise, real, property and other taxes. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20 -Article 5 false 46 Payable to PJM for FTRs 3 us-gaap_AccountsPayableOtherCurrent us-gaap true credit instant No definition available. false false false false false false false false false false false false 1 false true false false 10000000 10.0 false false false 2 false true false false 31700000 31.7 false false false xbrli:monetaryItemType monetary Carrying value as of the balance sheet date of obligations incurred and payable, which are not elsewhere specified in the taxonomy. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19 -Subparagraph a -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Chapter 3 -Section A -Paragraph 7 false 47 Derivative liabilities 3 us-gaap_DerivativeLiabilitiesCurrent us-gaap true credit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 4000000 4.0 false false false 2 false true false false 24400000 24.4 false false false xbrli:monetaryItemType monetary Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be extinguished or otherwise disposed of within a year or the normal operating cycle, if longer, net of the effects of master netting arrangements. 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Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). 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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Chapter 3 -Section A -Paragraph 8 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 6 -Paragraph 15 false 54 Total current liabilities 3 us-gaap_LiabilitiesCurrent us-gaap true credit instant No definition available. false false false false false false false false false false false totallabel false 1 false true false false 749900000 749.9 false false false 2 false true false false 985600000 985.6 false false false xbrli:monetaryItemType monetary Total obligations incurred as part of normal operations that are expected to be paid during the following twelve months or within one business cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 21 -Article 5 true 55 Long-term Debt: 2 us-gaap_LongTermDebtAbstract 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 xbrli:stringItemType string No definition available. false 56 Securitized debt - Environmental Control Bonds 3 us-gaap_LongTermPollutionControlBond us-gaap true credit instant No definition available. false false false false false false false false false false false false 1 false true false false 481000000 481.0 false false false 2 false true false false 496500000 496.5 false false false xbrli:monetaryItemType monetary Noncurrent portion of a debt security issued by a state, certain agencies or authorities, a local government, or development corporation to finance the construction of air- or water-pollution control facilities or sewage or solid waste disposal facilities pursuant to federal law. The bonds are backed by the credit of the beneficiary of the financing rather than the credit of the issuer. New issues of these bonds are prohibited under the 1986 Tax Law. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 false 57 Other long-term debt 3 us-gaap_OtherLongTermDebtNoncurrent us-gaap true credit instant No definition available. false false false false false false false false false false false false 1 false true false false 4069600000 4069.6 false false false 2 false true false false 3920500000 3920.5 false false false xbrli:monetaryItemType monetary Carrying value as of the balance sheet date of debt not otherwise defined (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. 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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 true 59 Deferred Credits and Other Liabilities: 2 us-gaap_OtherLiabilitiesNoncurrentAbstract 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 xbrli:stringItemType string No definition available. false 60 Derivative liabilities 3 us-gaap_DerivativeLiabilitiesNoncurrent us-gaap true credit instant No definition available. false false false false false false false false false false false verboselabel false 1 false true false false 4800000 4.8 false false false 2 false true false false 6700000 6.7 false false false xbrli:monetaryItemType monetary Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be extinguished or otherwise disposed of after one year or beyond the normal operating cycle, if longer, net of the effects of master netting arrangements. 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A noncurrent taxable temporary difference is a difference between the tax basis and the carrying amount of a noncurrent asset or liability in the financial statements prepared in accordance with generally accepted accounting principles. 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. 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No authoritative reference available. true 70 Commitments and Contingencies (Note 18) 2 us-gaap_CommitmentsAndContingencies2009 us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0     false false false 2 false false false false 0 0     false false false xbrli:stringItemType string Represents the caption on the face of the balance sheet to indicate that the entity has entered into (1) purchase or supply arrangements that will require expending a portion of its resources to meet the terms thereof, and (2) is exposed to potential losses or, less frequently, gains, arising from (a) possible claims against a company's resources due to future performance under contract terms, and (b) possible losses or likely gains from uncertainties that will ultimately be resolved when one or more future events that are deemed likely to occur do occur or fail to occur. 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Includes foreign currency translation items, certain pension adjustments, and unrealized gains and losses on certain investments in debt and equity securities as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. 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