Document and Entity Information [Abstract] Document and Entity Information Abstract. Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Document Fiscal Year Focus Document Fiscal Period Focus Current Fiscal Year End Date Entity Well Known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Filer Category Entity Common Stock Shares Outstanding Consolidated Statements of Income [Abstract] Consolidating Statements of Income Condensed Consolidated Statements of Income (Unaudited) Revenues Abstract REVENUES: Electric Domestic Regulated Revenue Electric utilities Unregulated businesses Electric Worldwide Unregulated Revenue Total revenues Electric Revenue Total revenues Revenues EXPENSES: Costs And Expenses Abstract Fuel Fuel Costs Purchased power Purchased power from non-affiliates Cost Of Purchased Power Other Cost And Expense Operating Other operating expenses Depreciation Nonproduction Provision for depreciation Amortization of regulatory assets Amortization of regulatory asset Taxes Excluding Income And Excise Taxes General taxes Total expenses Costs And Expenses Operating Income Loss OPERATING INCOME Other Income Expense Abstract OTHER INCOME (EXPENSE): Other Income Expense Abstract. Investment Income Interest And Dividend Investment income Investment income Investment income (loss), net Interest And Debt Expense Interest expense Interest and Debt Expense, Total Interest expense - other Capitalized interest Capitalized interest Public Utilities Allowance For Funds Used During Construction Additions Nonoperating Income Expense Total other income (expense) Total other expense Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments Pretax income INCOME BEFORE INCOME TAXES Income Tax Expense (Benefit) Income taxes INCOME TAXES Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net income (loss) NET INCOME NET INCOME Net Income Loss Attributable To Noncontrolling Interest Loss from noncontrolling interest COMPREHENSIVE LOSS ATTRIBUTABLE TO NONCONTROLLING INTEREST Loss attributable to noncontrolling interest Loss attributable to noncontrolling interest Net Income Loss EARNINGS AVAILABLE TO PARENT EARNINGS AVAILABLE TO FIRSTENERGY CORP Earnings available to FirstEnergy Corp. Earnings Per Share Basic Basic earnings per share of common stock BASIC EARNINGS PER SHARE OF COMMON STOCK Basic Earnings Per Share Weighted Average Number Of Shares Outstanding Basic Average shares of common stock outstanding, Basic WEIGHTED AVERAGE NUMBER OF BASIC SHARES OUTSTANDING Weighted average number of basic shares outstanding Earnings Per Share Diluted Diluted earnings per share of common stock DILUTED EARNINGS PER SHARE OF COMMON STOCK Diluted Earnings Per Share Weighted Average Number Of Diluted Shares Outstanding Average shares of common stock outstanding, Diluted WEIGHTED AVERAGE NUMBER OF DILUTED SHARES OUTSTANDING Weighted average number of diluted shares outstanding Common Stock Dividends Per Share Declared DIVIDENDS DECLARED PER SHARE OF COMMON STOCK Dividends declared Excise tax collections Excise And Sales Taxes Comprehensive Income Net Of Tax COMPREHENSIVE INCOME AVAILABLE TO FIRSTENERGY CORP. Comprehensive income Balance Sheets [Abstract] Consolidating Balance Sheets Condensed Consolidating Balance Sheets (Unaudited) Assets [Abstract] ASSETS CURRENT ASSETS: Assets Current Abstract Cash And Cash Equivalents At Carrying Value Cash and cash equivalents at end of period Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value, Total Cash and cash equivalents Receivables Net Current [Abstract] Receivables- Accounts Receivable Net Current Customers Accounts Receivable, Net, Current, Total Customers, net of allowance for uncollectible accounts of $38 in 2011 and $36 in 2010 Other Receivables Other Other, net of allowance for uncollectible accounts of $10 in 2011 and $8 in 2010 Inventory Net Materials and supplies Prepaid taxes Prepaid Taxes Prepayments and other Other Other Assets Current Total current assets Assets Current PROPERTY, PLANT AND EQUIPMENT: Property Plant And Equipment Net Abstract Property Plant And Equipment Gross Property, Plant and Equipment, Gross, Ending Balance Property, Plant and Equipment, Gross, Beginning Balance Property, Plant and Equipment, Gross, Total In service Less - Accumulated provision for depreciation Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Accumulated Depreciation Depletion And Amortization Property Plant And Equipment, Ending Balance Accumulated Depreciation Depletion And Amortization Property Plant And Equipment, Beginning Balance Less accumulated depreciation Net Plant Excluding Construction Work In Progress Net plant in service Total in service, accumulated provision for depreciation Net Plant Excluding Construction Work In Progress. Construction In Progress Gross Construction work in progress Construction work in progress Property, Plant And Equipment, Net Property, Plant and Equipment, Net, Ending Balance Property, Plant and Equipment, Net, Beginning Balance Net plant in service Net plant in service INVESTMENTS: Investments Abstract Nuclear plant decommissioning trusts Decommissioning Fund Investments Investments in lease obligation bonds Held To Maturity Securities Noncurrent Other Other Long Term Investments Long Term Investments Total investments Assets Deferred Charges And Other Assets Abstract DEFERRED CHARGES AND OTHER ASSETS: Deferred Charges And Other Assets Abstract. Goodwill Balance at March 31, 2011 Balance at December 31, 2010 Total goodwill Goodwill Regulatory Assets Noncurrent Regulatory Assets Regulatory assets Other Other Assets Noncurrent Total deferred charges and other assets Assets Noncurrent Total assets Total assets Assets Liabilities And Capitalization Abstract LIABILITIES AND CAPITALIZATION Liabilities And Capitalization Abstract. CURRENT LIABILITIES: Liabilities Current Abstract Long Term Debt And Capital Lease Obligations Current Long-term debt due within one year Long-term debt due within one year Currently payable long-term debt Short-term borrowings Other Short Term Borrowings Accounts payable Other Accounts Payable Current Accrued taxes Accrued Income Taxes Current Other Other Liabilities Current Total current liabilities Liabilities, Current Capitalization [Abstract] CAPITALIZATION: Common stockholders' equity- Stockholders Equity Abstract Common Stock Value Outstanding Common stock, $0.10 par value, authorized 490,000,000 shares-418,216,437 shares outstanding Additional Paid In Capital Common Stock Additional Paid in Capital, Common Stock, Ending Balance Additional Paid in Capital, Common Stock, Beginning Balance Other paid in capital resulted from acquisitions Other paid-in capital Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance AOCL Balance Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive loss Retained Earnings Accumulated Deficit Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit), Beginning Balance Retained earnings Unrestricted retained earnings Stockholders Equity Ending Balance Beginning Balance Common stockholder's equity Total common stockholders' equity Noncontrolling interest Minority Interest Ending Balance Beginning Balance Stockholders Equity Including Portion Attributable To Noncontrolling Interest Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Total Total equity Long Term Debt And Capital Lease Obligations Long-term debt and other long-term obligations Long-term debt and other long-term obligations Total Capitalization Total capitalization Total Capitalization. NONCURRENT LIABILITIES: Liabilities Noncurrent Abstract Accumulated deferred income taxes Deferred Tax Liabilities Noncurrent Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent Net liability of stock option Noncurrent liabilities Retirement benefits Asset retirement obligations Asset Retirement Obligations Noncurrent Deferred gain on sale and leaseback transaction Sale Leaseback Transaction Deferred Gain Net Power Purchase Contract Liability Power purchase contract liability Power purchase contract liability. Lease market valuation liability Off Market Lease Unfavorable Other Other Liabilities Noncurrent Total noncurrent liabilities Liabilities Noncurrent Commitments And Contingencies 2009 COMMITMENTS, GUARANTEES AND CONTINGENCIES (Note 9) Total liabilities and capitalization Liabilities And Stockholders Equity Accumulated provision for uncollectible accounts - customer Allowance For Doubtful Accounts Receivable Current Accumulated Provision For Uncollectible Accounts Other Accumulated provision for uncollectible accounts - other Accumulated Provision For Uncollectible Accounts Other. Common stock, par value Common Stock Par Or Stated Value Per Share Common stock, shares authorized Common Stock Shares Authorized Common Stock Shares Outstanding Ending Balance, Shares Beginning Balance, Shares Common stock, shares outstanding Consolidated Statements of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided By Used In Operating Activities Abstract Adjustments to reconcile net income to net cash from operating activities- Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities Abstract Nuclear fuel and lease amortization Other Amortization Of Deferred Charges Deferred purchased power and other costs Deferred Purchased Power Costs Deferred income taxes and investment tax credits, net Deferred Income Taxes And Tax Credits Deferred rents and lease market valuation liability Deferred rents and lease market valuation liability Deferred rents and lease market valuation liability Deferred Rents And Lease Market Valuation Liability. Accrued compensation and retirement benefits Increase Decrease In Employee Related Liabilities Gain Loss On Derivatives Commodity derivative transactions, net Commodity derivative transactions, net The gains and losses from increase (decrease) in fair value of derivatives included in earnings. Cash Collateral Net Cash collateral paid Cash Collateral Net. Increase Decrease In Operating Assets Abstract Decrease (increase) in operating assets- Receivables Increase Decrease In Accounts And Other Receivables Materials and supplies Increase Decrease In Inventories Prepayments and other current assets Increase Decrease In Prepaid Expense Increase (decrease) in operating liabilities- Increase Decrease In Operating Liabilities Abstract Accounts payable Increase Decrease In Accounts Payable Trade Accrued taxes Increase Decrease In Accrued Income Taxes Payable Accrued interest Increase Decrease In Interest Payable Net Other Increase Decrease In Other Operating Capital Net Net cash provided from operating activities NET CASH PROVIDED FROM (USED FOR) OPERATING ACTIVITIES Net Cash Provided By Used In Operating Activities CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided By Used In Financing Activities Abstract New Financing [Abstract] New Financing- New financing- New Financing Abstract. Long-term debt Proceeds From Issuance Of Long Term Debt, Total Proceeds From Issuance Of Long Term Debt Short-term borrowings, net Proceeds From Short Term Debt, Total Proceeds From Short Term Debt Redemptions And Repayments [Abstract] Redemptions and Repayments- Redemptions and repayments- Redemptions And Repayments Abstract. Long-term debt Repayments Of Long Term Debt, Total Long-term debt Repayments Of Long Term Debt Repayments Of Short Term Debt Short-term borrowings, net Repayments Of Short Term Debt, Total Short-term borrowings, net Payments Of Dividends Common Stock Common stock dividend payment Common stock dividend payments Other Proceeds From (Payments For) Other Financing Activities Net cash provided from (used for) financing activities Net cash used for financing activities Net Cash Provided By Used In Financing Activities CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided By Used In Investing Activities Abstract Property additions Payments To Acquire Productive Assets, Total Property additions Payments To Acquire Productive Assets Proceeds from asset sales Proceeds from asset sales Proceeds from asset sales Sales of investment securities held in trusts Proceeds From Sale Of Available For Sale Securities, Total Proceeds From Sale Of Available For Sale Securities Purchases of investment securities held in trusts Payments to Acquire Available-for-sale Securities, Total Purchases of investment securities held in trusts Payments To Acquire Available For Sale Securities Payments To Acquire Intangible Assets Customer acquisition costs Payments For Proceeds From Investments Cash investments Payments for (Proceeds from) Investments, Total Cash investments Other Other Payments for (Proceeds from) Other Investing Activities Net Cash Provided by (Used in) Investing Activities Net cash provided from (used for) investing activities Cash And Cash Equivalents, Period Increase (Decrease) Net change in cash and cash equivalents Cash And Cash Equivalents, Period Increase (Decrease), Total Net change in cash and cash equivalents Organization and Basis of Presentation [Abstract] Organization And Basis Of Presentation Abstract. ORGANIZATION AND BASIS OF PRESENTATION Organization Consolidation And Presentation Of Financial Statements Disclosure Text Block Fair Value Disclosures Text Block FAIR VALUE OF FINANCIAL INSTRUMENTS Derivative Instruments [Abstract] Derivative Instruments Abstract. DERIVATIVE INSTRUMENTS Derivative Instruments And Hedging Activities Disclosure Text Block Pension And Other Postretirement Benefits Disclosure Text Block PENSION AND OTHER POSTRETIREMENT BENEFITS Variable Interest Entities [Abstract] Variable Interest Entities Abstract. VARIABLE INTEREST ENTITIES Schedule Of Variable Interest Entities Text Block Income Taxes [Abstract] Income Taxes Abstract. INCOME TAXES Income Tax Disclosure Text Block Commitments, Guarantees and Contingencies [Abstract] Commitments Guarantees And Contingencies Abstract. COMMITMENTS, GUARANTEES AND CONTINGENCIES Commitments And Contingencies Disclosure Text Block Regulatory Matters [Abstract] Regulatory Matters Abstract. Public Utilities Disclosure Text Block REGULATORY MATTERS New Accounting Standards and Interpretations [Abstract] New Accounting Standards and Interpretations [Abstract] Schedule Of New Accounting Pronouncements And Changes In Accounting Principles Text Block NEW ACCOUNTING STANDARDS AND INTERPRETATIONS Supplemental Guarantor Information [Abstract] Supplemental Guarantor Information Abstract. Supplemental Guarantor Information Disclosure Text Block SUPPLEMENTAL GUARANTOR INFORMATION Supplemental Guarantor Information Disclosure Text Block. Segment Information [Abstract] Segment Information Abstract. SEGMENT INFORMATION Segment Reporting Disclosure Text Block Fair Value of Financial Instruments (Tables) [Abstract] Fair Value of Financial Instruments. Fair value and related carrying amounts of long term debt and other long term obligations Text Block Fair value and related carrying amounts of long-term debt and other long-term obligations Fair value and related carrying amounts of long-term debt and other long-term obligations. Amortized cost basis, unrealized gains and losses and fair values of investments in available-for-sale securities Available For Sale Securities Text Block Proceeds from sale of investments in available for sale securities realized gains and losses on those sales and interest and dividend income Text Block Proceeds from the sale of investments in available-for-sale securities, realized gains and losses on those sales, and interest and dividend income Proceeds from sale of investments in available-for-sale securities, realized gains and losses on those sales, and interest and dividend income. Amortized cost basis, unrealized gains and losses, and approximate fair values of investments in held-to-maturity securities Held To Maturity Securities Text Block Derivative Instruments (Tables) [Abstract] Derivative Instruments. Fair value of commodity derivatives Text Block Fair value of commodity derivatives Fair value of commodity derivatives. Volume Of Parent Companys Outstanding Derivative Transactions Text Block Volume of First Energy's outstanding derivative transactions Volume Of Parent Company's Outstanding Derivative Transactions. Variable Interest Entities (Tables) [Abstract] Variable Interest Entities. Segment Information (Tables) [Abstract] Segment Information. Segment Financial Information Schedule Of Segment Reporting Information By Segment Text Block Supplemental Guarantor Information (Tables) [Abstract] Supplemental Guarantor Information. Segment Reporting Information, by Segment [Axis] Reporting Segment [Domain] Energy Delivery Services [Member] Energy Delivery Services. Competitive Energy Services [Member] Competitive Energy Services Competitive Energy Services Competitive Energy Services. Legal Entity [Axis] Entity [Domain] Fair Value of Financial Instruments (Details) [Abstract] Fair Value of Financial Instruments. Public Utility [Axis] Utility Plant Domain Schedule of Available for Sale Securities Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Equity Securities [Member] Equity Securities Corporate Debt Securities [Member] Debt Securities Fair Value by Balance Sheet Grouping Disclosure Item Amounts [Axis] Fair Value Disclosure Item Amounts [Domain] Carrying Value [Member] Carrying Value Fair Value [Member] Fair Value