No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Fair Value Assets Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Text Block No authoritative reference available. No authoritative reference available. No authoritative reference available. Tangible assets that are held by an entity for use other than utility production; net of accumulated depreciation. No authoritative reference available. No authoritative reference available. No authoritative reference available. Provision for injuries and damages. No authoritative reference available. Aggregate Accrued Liabilities Related To Superfund Sites No authoritative reference available. Derivative Asset Not Designated As Hedging Instrument Fair Value Net After Offset Under Master Netting Agreement No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. MWs No authoritative reference available. No authoritative reference available. No authoritative reference available. IRS Disallowed Deduction No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Schedule Of Net Periodic Benefit Cost Other Postretirement Benefits No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Carrying amount as of the balance sheet date of long-lived, depreciable electric utility plant. No authoritative reference available. Capital contributions from parent. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Accrued Liabilities And Regulatory Assets Text Block No authoritative reference available. Number of Capacity Contracts No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Income before interest income, interest expense and income taxes No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Fair Value of Commodity Derivative Liabilities Transfers Out No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Maximum Potential Future Exposure On Credit Risk Derivatives Total No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Derivative Liability Not Designated As Hedging Instrument Fair Value Net After Offset Under Master Netting Agreement No authoritative reference available. No authoritative reference available. No authoritative reference available. Maximum Potential Future Exposure On Credit Risk Derivatives With Investment Grade Counterparties No authoritative reference available. Total Other Assets No authoritative reference available. Fair Value Of Commodity Derivative Liabilities Transfers In No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. MWHS No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Schedule Of Regulatory Assets And Liabilities Table [Text Block] No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Carrying amount as of the balance sheet date of long-lived, depreciable general utility plant. No authoritative reference available. Represents the noncurrent portion of deferred tax liabilities and the reserve for accumulated deferred investment tax credits as of the balance sheet date, 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 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. This is the remaining investment credit, which will reduce the cost of services collected from ratepayers by a ratable portion over the investment's regulatory life. No authoritative reference available. No authoritative reference available. No authoritative reference available. Schedule of net periodic benefit cost. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Deferred gain/(loss), liability No authoritative reference available. No authoritative reference available. No authoritative reference available. Schedule of Energy Price Hedges, Fair Value No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Regulatory Assets Workers Compensation No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Accrued Liabilities For Asbestos Suits And Workers Compensation Proceedings [Text Block] No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Current portion of intercompany tax payable No authoritative reference available. Accrued Liabilities Asbestos Suits No authoritative reference available. Deferred Credits and Regulatory Liabilities No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Capitalization [Text Block] No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Energy related inventory, fuel oil, gas and materials and supplies, cost No authoritative reference available. Revenue Decoupling Mechanism Receivable No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Other Superfund Sites Accrued Liabilities No authoritative reference available. Describes any existing condition, situation, or set of circumstances involving uncertainty as of the balance sheet date (or prior to issuance of the financial statements) as to a probable or reasonably possible gain or loss incurred by an entity and typically discloses the amount of range of possible gain or loss recorded. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Included In regulatory Assets And Liabilities No authoritative reference available. No authoritative reference available. No authoritative reference available. Defined Benefit Plan Cost Charged To Operating Expenses No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Comprehensive Income Available to Common Stockholders, Net of Tax No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Carrying amount at the balance sheet date for long-lived physical utility assets used in the normal conduct of business. Amount does not include depreciation. No authoritative reference available. Income Tax Paid Upon IRS Examination No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Lease in lease out total financed by equity No authoritative reference available. Lease in lease out total investment No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Total Periodic Benefit Cost After Amortization of Regulatory Asset No authoritative reference available. No authoritative reference available. No authoritative reference available. Common Stock Equity Shares No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Number of Energy Contracts No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Dths No authoritative reference available. No authoritative reference available. No authoritative reference available. Defined Benefit Plan Cost Deferred No authoritative reference available. No authoritative reference available. No authoritative reference available. Tangible assets that are held by an entity for use in the production or supply of utilities and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Value of stock issued as a result of dividend reinvestment and employee stock purchase plan recorded above par value. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Stock Issued During Period, Shares, Dividend reinvestment and Employee Stock Purchase Plan No authoritative reference available. No authoritative reference available. No authoritative reference available. Deferred gain/(loss), asset No authoritative reference available. No authoritative reference available. No authoritative reference available. Defined Benefit Plan Cost Capitalized No authoritative reference available. No authoritative reference available. No authoritative reference available. Regulatory Assets Asbestos Suits No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Accrued Liabilities Workers Compensation No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Environmental Remediation Costs Incurred Related To Superfund Sites [Text Block] No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Superfund Manufactured Gas Plant Sites Accrued Liabilities No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Leveraged Lease Gross Investment In Leveraged Leases Disclosure Investment In Leveraged Leases Gross No authoritative reference available. No authoritative reference available. No authoritative reference available. A provision for other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Maximum Potential Future Exposure On Credit Risk Derivatives With Commodity Exchange Brokers No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Lease In Lease Out Total Financed By Non Recourse Long Term Debt No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Carrying amount as of the balance sheet date of long-lived, depreciable steam utility plant. No authoritative reference available. Net derferred gain/(loss) No authoritative reference available. Carrying amount as of the balance sheet date of long-lived, depreciable gas utility plant. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Tax Savings From LILO Transactions No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Total value of common stock equity No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. No authoritative reference available. Assets and Liabilities Measured at Fair Values on a Recurring Basis. No authoritative reference available.