Earnings Per Share [Abstract] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Option Indexed to Issuer's Equity, Type [Axis] Option Indexed to Issuer's Equity, Type [Axis] Option Indexed to Issuer's Equity, Type [Domain] Option Indexed to Issuer's Equity, Type [Domain] Employee Stock Option [Member] Employee Stock Option [Member] Forward Contract Indexed to Issuer's Equity, Type [Axis] Forward Contract Indexed to Issuer's Equity, Type [Axis] Forward Contract Indexed to Issuer's Equity, Type [Domain] Forward Contract Indexed to Issuer's Equity, Type [Domain] Equity Forward Units [Member] Equity Forward Units [Member] Equity Forward Units issued in connection with the junior subordinated notes issued by Exelon to fund the PHI merger. Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] PECO Energy Co [Member] PECO Energy Co [Member] PECO Energy Co [Member] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Treasury Stock, Shares held Treasury Stock, Shares Treasury Stock, Value Treasury Stock, Value Preferred Stock Redemption Premium Preferred Stock Redemption Premium PECO Cumulative Preferred Securities Redeemable Stock Redeemed or Called During Period, Value Stock options not included in the calculation of diluted common shares outstanding Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Business Combinations [Abstract] Assets Disposition Table [Table] Assets Disposition Table [Table] Assets Disposition Table [Table] Long Lived Assets Held-for-sale by Asset Type [Axis] Long Lived Assets Held-for-sale by Asset Type [Axis] Long Lived Assets Held-for-sale, Name [Domain] Long Lived Assets Held-for-sale, Name [Domain] Electricity Generation Plant, Non-Nuclear [Member] Electricity Generation Plant, Non-Nuclear [Member] Quail Run Generating Facility [Member] Quail Run Generating Facility [Member] Quail Run Generating Facility [Member] Exelon Generation Co L L C [Member] Exelon Generation Co L L C [Member] Exelon Generation Co LLC [Member] Assets Disposition Table [Line Items] Assets Disposition Table [Line Items] [Line Items] for Assets Disposition Table [Table] Proceeds from Sale of Productive Assets Proceeds from Sale of Productive Assets Property, plant and equipment, net (a) Disposal Group, Including Discontinued Operation, Property, Plant and Equipment, Current Inventory Disposal Group, Including Discontinued Operation, Inventory, Current Current assets Disposal Group, Including Discontinued Operation, Other Assets, Current Total assets held for sale Disposal Group, Including Discontinued Operation, Assets, Current Accounts payable Accounts Payable, Trade, Current Accrued expenses Accrued Liabilities, Current Other current liabilities Other Liabilities, Current Total liabilities held for sale (b) Disposal Group, Including Discontinued Operation, Liabilities Asset Impairment Charges Asset Impairment Charges Proceed from sale of asset net of tax Proceed from sale of asset net of tax Proceed from sale of asset net of tax Commitments and Contingencies Disclosure [Abstract] Accrual For Environmental Loss Contingencies [Table] Accrual For Environmental Loss Contingencies [Table] Accrual For Environmental Loss Contingencies [Table] Environmental Remediation Contingency [Axis] Environmental Remediation Contingency [Axis] Environmental Remediation Contingency [Domain] Environmental Remediation Contingency [Domain] Cotter Corporation [Member] Cotter Corporation [Member] Sixty-Eighth Street Dump [Member] Sixty-Eighth Street Dump [Member] Rossville ash site [Member] Rossville Ash Site [Member] Accrual For MGP Investigation And Remediation [Member] Accrual For MGP Investigation And Remediation [Member] Represents the portion of the total environmental investigation and remediation reserve related to manufactured gas plant investigation and remediation. Commonwealth Edison Co [Member] Commonwealth Edison Co [Member] Commonwealth Edison Co [Member] Midwest Generation, LLC [Member] Midwest Generation, LLC [Member] Baltimore Gas and Electric Company [Member] Baltimore Gas and Electric Company [Member] Accrual For Environmental Loss Contingencies [Line Items] Accrual For Environmental Loss Contingencies [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Total number of MGP sites Mgp Site Contingency Count Total number of individual manufactured gas plant sites with associated possible environmental loss contingencies related to remediation. Approved clean-up Mgp Site Contingency Approved Cleanup Count Number of individual manufactured gas plant sites at which the respective state environmental agency has approved a cleanup plan. Sites under study/remediation Mgp Site Contingency Monitoring Count Number of individual manufactured gas plant sites where monitoring or remediation activities are occurring. Accrual for Environmental Loss Contingencies, Period Increase (Decrease) Accrual for Environmental Loss Contingencies, Period Increase (Decrease) Low end of range of cooling tower cost Site Contingency, Loss Exposure Not Accrued, Low Estimate Consent decree penalty Payments for Environmental Liabilities Environmental loss contingencies Accrual for Environmental Loss Contingencies, Component Amount States subject to the Cross State Air Pollution Rule States Subject To Cross State Air Pollution Rule Number of states subject to the Cross State Air Pollution Rule (CSAPR) Emissions allowance balance Emissions Allowance Balance Emission Credits Or Allowances Balance. Net investment in long-term direct financing leases Capital Leases, Net Investment in Direct Financing Leases Payments for operating leases Payment Of Operating Lease Payments for operating leases. Coal Rail Car Lease Proof of Claims Bankruptcy Claims, Amount of Claims Filed Increase (decrease) in the value of the asbestos liability reserve Asbestos Loss Contingency Accrual Period Increase Decrease Net change in the accrual for asbestos-related loss contingencies during the reporting period. Midwest Generation's estimated environmental investigation and remediation costs Environmental Exit Costs, Assets Previously Disposed, Liability for Remediation Total cost of remediation to be shared by PRPs Site Contingency, Loss Exposure Not Accrued, Best Estimate DOJ potential settlement Environmental Exit Costs, Reasonably Possible Additional Losses, High Estimate Loss Contingency, Number of Defendants Loss Contingency, Number of Defendants Number Of Stations Violating Clean Air Act Number Of Stations Violating Clean Air Act Number of sites according to the US EPA that have violated and continue to violate several provisions of the Clean Air Act Loss Contingency Number Of Parties Jointly And Severally Liable In Environmental Protection Agency Action Loss Contingency Number Of Parties Jointly And Severally Liable In Environmental Protection Agency Action Identifies number of individuals or entities that are co-defendants in an EPA Investigation. Minimum estimated clean-up costs for all potentially responsible parties Loss Contingency, Range of Possible Loss, Minimum Maximum estimated clean-up costs for all potentially responsible parties Loss Contingency, Range of Possible Loss, Maximum Loss Contingency, Estimate of Possible Loss Loss Contingency, Estimate of Possible Loss Minimum GHG emissions by stationary sources to qualify for regulation Minimum Ghg Emissions Required For Eligibility For Stationary Source Permitting Represents the minimum level, in tons per year, of GHG emissions required to be eligible for permitting regulation proposed by the U.S. Environmental Protection Agency. Minimum additional GHG emissions by stationary sources after a modification Minimum Additional Ghg Emissions Required For Eligibility For Stationary Source Permitting After Modifications Represents the minimum increase as a result of a modification to a major stationary emissions source, in tons per year, of GHG emissions required to be eligible for permitting regulation proposed by the U.S. Environmental Protection Agency. Effective Number Of Years For Tailoring Rule Effective Number Of Years For Tailoring Rule Effective number of years for the Tailoring Rule under the Clean Air Act. LossContingencySettlementAgreementPercentagePayable LossContingencySettlementAgreementPercentagePayable LossContingencySettlementAgreementPercentagePayableByThirdParty Litigation Settlement, Amount Litigation Settlement, Amount Other Increase (Decrease) in Environmental Liabilities Other Increase (Decrease) in Environmental Liabilities Increase (Decrease) in Other Regulatory Assets Increase (Decrease) in Other Regulatory Assets Fair Value Disclosures [Abstract] Fair Value Assets Liabilities Measured On Recurring Basis [Table] Summarization of information required and determined to be disclosed concerning assets and liabilities, including [financial] instruments that are classified in stockholders' equity, which are measured at fair value on a recurring basis. Fair Value Assets And Liabilities Measured On Recurring Basis Disclosure Items [Axis] Fair Value Assets And Liabilities Measured On Recurring Basis Disclosure Items [Axis] This element represents a number of concepts which are required or desirable disclosure items concerning assets and liabilities, including [financial] instruments that are classified in stockholders' equity, which are measured at fair value on a recurring basis. Fair Value Assets And Liabilities Measured On Recurring Basis [Domain] Fair Value Assets And Liabilities Measured On Recurring Basis [Domain] Provides the general information items required or determined to be disclosed with respect to assets and liabilities, including [financial] instruments that are classified in stockholders' equity, which are measured at fair value on a recurring basis. Nuclear Decommissioning [Member] Nuclear Decommissioning [Member] Represents estimated future nuclear decommissioning costs that exceed (regulatory asset) or are less than (regulatory liability) the associated decommissioning trust fund assets. Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Nuclear Decommissioning Trust Fund Investments [Member] Nuclear Decommissioning Trust Fund Investments [Member] This element represents the assets measured at fair value on a recurring basis related to nuclear decommissioning trust fund investments. Cash Equivalents [Member] Cash Equivalents [Member] Equity Funds [Member] Equity Funds [Member] Private Equity Funds, Domestic [Member] Private Equity Funds, Domestic [Member] Private Equity Funds, Foreign [Member] Private Equity Funds, Foreign [Member] Equity Funds Zion Decom [Member] Equity Funds Zion Decom [Member] Equity Funds Zion Decom [Member] Fixed Income Securities [Member] Fixed Income Securities [Member] Corporate Debt Securities [Member] Corporate Debt Securities [Member] CorporateDebtSecuritiesZoin Decom [Member] CorporateDebtSecuritiesZoin Decom [Member] CorporateDebtSecuritiesZoin Decom [Member] US Treasury and Government [Member] US Treasury and Government [Member] US Treasury And Government Zion Decom [Member] US Treasury And Government Zion Decom [Member] US Treasury And Government Zion Decom [Member] Foreign Government Debt Securities [Member] Foreign Government Debt Securities [Member] Foreign Government Debt Securities Zion Decom [Member] Foreign Government Debt Securities Zion Decom [Member] Foreign Government Debt Securities Zion Decom [Member] State and municipal debt [Domain] State and municipal debt [Domain] State and municipal debt [Domain] State and Municipal Debt Zion Decom [Member] State and Municipal Debt Zion Decom [Member] State and Municipal Debt Zion Decom [Member] Other Fixed Income [Member] Other Fixed Income [Member] Other Fixed Income [Member] Other Fixed income Zoin Decom [Member] Other Fixed income Zoin Decom [Member] Other Fixed income Zoin Decom [Member] Fixed Income Securities Zion Decom [Member] Fixed Income Securities Zion Decom [Member] Fixed Income Securities Zion Decom [Member] Middle market lending [Member] Middle market lending [Member] Middle market lending [Member] Private Equity Funds [Member] Private Equity Funds [Member] Real Estate Funds [Member] Real Estate Funds [Member] Other [Member] Other [Member] Other [Member] Pledged Assets For Zion Station Decommissioning [Member] Pledged Assets For Zion Station Decommissioning [Member] This element represents the assets measured at fair value on a recurring basis related to pledged assets for Zion Station decommissioning. Cash Equivalent Zion [Member] Cash Equivalent Zion [Member] Cash Equivalent Zion [Member] MiddleMarketLending Zoin Decom [Member] MiddleMarketLending Zoin Decom [Member] MiddleMarketLending Zoin Decom [Member] Rabbi Trust Investments [Member] Rabbi Trust Investments [Member] This element represents the assets measured at fair value on a recurring basis related to rabbi trust investments. Commodity Derivative Assets [Member] Commodity Derivative Assets [Member] Commodity Derivative Assets [Member] Economic Hedging Instrument [Member] Economic Hedging Instrument [Member] Economic Hedging Instrument [Member] Proprietary Trading [Member] Proprietary Trading [Member] Energy-related derivative contracts entered into purely to profit from market prices changes as opposed to hedging an exposure. Effects of Netting and Allocation of Collateral [Member] Effects of Netting and Allocation of Collateral [Member] Effects of Netting and Allocation of Collateral [Member] Economic hedge Interest and Currency [Member] Economic hedge Interest and Currency [Member] Economic hedge Interest and Currency [Member] Interest Rate and Foreign Currency Derivative Assets [Member] Interest Rate and Foreign Currency Derivative Assets [Member] Interest Rate and Foreign Currency Derivative Assets [Member] Designated as Hedging Instrument [Member] Designated as Hedging Instrument [Member] Proprietary Trading Interest and Currency Derivative [Member] Proprietary Trading Interest and Currency Derivative [Member] Proprietary Trading Interest and Currency Derivative [Member] EffectsofNettingandAllocationofCollateral1 [Member] EffectsofNettingandAllocationofCollateral1 [Member] EffectsofNettingandAllocationofCollateral1 [Member] Other Investments [Member] Other Investments [Member] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Commodity Derivative Liabilites [Member] Commodity Derivative Liabilites [Member] Commodity Derivative Liabilites [Member] Economic Hedging Instrument Liabilites [Member] Economic Hedging Instrument Liabilites [Member] Economic Hedging Instrument Liabilites [Member] Proprietary Trading Liabilities [Member] Proprietary Trading Liabilities [Member] Proprietary Trading Liabilities [Member] Effects of Netting and Allocation of Collateral Liabilites [Member] Effects of Netting and Allocation of Collateral Liabilites [Member] Effects of Netting and Allocation of Collateral Liabilites [Member] Interest Rate and Foreign Currency Derivative Liabilities [Member] Interest Rate and Foreign Currency Derivative Liabilities [Member] Interest Rate and Foreign Currency Derivative Liabilities [Member] EconomicHedgingInstrumentLiabilites1 [Member] EconomicHedgingInstrumentLiabilites1 [Member] EconomicHedgingInstrumentLiabilites1 [Member] Derivatives Designated As Hedging Instruments Liabilities [Domain] Derivatives Designated As Hedging Instruments Liabilities [Domain] Derivatives Designated As Hedging Instruments Liabilities [Domain] Proprietary Trading Liabilities Interest and FX [Domain] Proprietary Trading Liabilities Interest and FX [Domain] Proprietary Trading Liabilities Interest and FX [Domain] Effect of Netting and Allocation of Collateral Interest Rate and FX Liabilities [Domain] Effect of Netting and Allocation of Collateral Interest Rate and FX Liabilities [Domain] Effect of Netting and Allocation of Collateral Interest Rate and FX Liabilities [Domain] Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items] Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. 0 Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] Cash and Cash Equivalents, Fair Value Disclosure Cash and Cash Equivalents, Fair Value Disclosure Investments, Fair Value Disclosure Investments, Fair Value Disclosure Derivative Asset Derivative Asset FinancialAssetsFairValueDisclosure1 FinancialAssetsFairValueDisclosure1 FinancialAssetsFairValueDisclosure1 Derivative Liability, Noncurrent Derivative Liability, Noncurrent Deferred Compensation Liability, Current and Noncurrent Deferred Compensation Liability, Current and Noncurrent Financial Liabilities Fair Value Disclosure Financial Liabilities Fair Value Disclosure FinancialAssetLiabilitiesNetFairValueDisclosure1 FinancialAssetLiabilitiesNetFairValueDisclosure1 FinancialAssetLiabilitiesNetFairValueDisclosure1 Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract] Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract] Net assets (liabilities) excluded from nuclear decommissioning trust fund investments Fair Value Net Assets Liabilities Excluded From Nuclear Decommissioning Trust Fund Investments This element represents total net assets (liabilities) excluded from nuclear decommissioning trust fund investment total. The amount consists of payables related to pending securities purchases net of cash, interest receivables and receivables related to pending securities for the respective periods. Supplemental executive retirement plan fair value Supplemental Executive Retirement Plan Fair Value Fair value of retirement plan investments recorded at fair value. Cash surrender value of life insurance investments excluded from Rabbi Trust investments Cash Surrender Value of Life Insurance Collateral received from counterparties, net of collateral paid to counterparties Derivative, Fair Value, Amount Offset Against Collateral, Net Derivative Liability, Current Derivative Liability, Current Derivative Liability Derivative Liability Deferred Compensation Plan Assets Deferred Compensation Plan Assets Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Analysis and reconciliation of reportable segment information Schedule of Segment Reporting Information, by Segment [Table Text Block] Analysis and reconciliation of reportable segment revenues for Generation Revenue from External Customers by Geographic Areas [Table Text Block] Environmental Remediation Obligations [Abstract] Nuclear Decommissioning (Exelon and Generation) Asset Retirement Obligation Disclosure [Text Block] Changes in Accumulated Other Comprehensive Income [Abstract] Changes in Accumulated Other Comprehensive Income [Abstract] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Accumulated Net Unrealized Investment Gain (Loss) [Member] Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Accumulated Defined Benefit Plans Adjustment [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Accumulated Translation Adjustment [Member] Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Accumulated Equity Investment [Member] Accumulated Equity Investment [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Movement in Accumulated Other Comprehensive Income [Roll Forward] Movement in Accumulated Other Comprehensive Income [Roll Forward] Movement in Accumulated Other Comprehensive Income [Roll Forward] Beginning balance Accumulated Other Comprehensive Income (Loss), Net of Tax OCI before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Amounts reclassified from AOCI Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Net current-period OCI Other Comprehensive Income (Loss), Net of Tax Ending balance Income Tax Disclosure [Abstract] Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Commitments and Contingencies (Exelon, Generation, ComEd, PECO and BGE) Commitments and Contingencies Disclosure [Text Block] Schedule of Segment Reporting Information, by Segment [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Commonwealth Edison Co Affiliate [Member] Commonwealth Edison Co Affiliate [Member] Commonwealth Edison Co Affiliate. Corporate and Other [Member] Corporate and Other [Member] Segment Elimination [Member] Segment Elimination [Member] Segment Elimination Member created to differentiate between Intersegment Elimination member Generation Mid Atlantic [Member] Generation Mid Atlantic [Member] Represents the Mid-Atlantic segment of Exelon Corporation and Exelon Generation Company, LLC. Generation Midwest [Member] Generation Midwest [Member] Represents the Midwest segment of Exelon Corporation and Exelon Generation Company, LLC. Generation New England [Member] Generation New England [Member] Represents the New England segment of Exelon Corporation and Exelon Generation Company, LLC. Generation New York [Member] Generation New York [Member] Generation ERCOT [Member] Generation ERCOT [Member] Generation Other Regions [Member] Generation Other Regions [Member] Generation Reportable Segments Total [Member] Generation Reportable Segments Total [Member] Generation All Other Segments [Member] Generation All Other Segments [Member] Operating segments that do not meet the quantitative thresholds and thus are not classified as reportable segments for which there is an accounting requirement to report separate financial information on those components in the entity's financial statements. Generation Total Consolidated Group [Member] Generation Total Consolidated Group [Member] This member is equivalent to Exelon Generation Co LLC in most cases for segment reporting except for intersegment activity.The consolidated group for intersegment activity represents activity between the segments within the Generation consolidated group as opposed to the activity between Generation and the Exelon consolidated group. Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments [Member] Operating Segments [Member] Other Segment [Member] Other Segment [Member] Represents the corporate operations of an entity. Intersegment Eliminations [Member] Intersegment Eliminations [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Sales Revenue, Goods, Net [Member] Sales Revenue, Goods, Net [Member] Unrealized Gain (Loss) on Commodity Contracts Unrealized Gain (Loss) on Commodity Contracts Revenues Revenue from Related Parties Revenue from Related Parties Net income (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Amortization of Intangible Assets Amortization of Intangible Assets Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Syndicated Revolver 1 [Member] Syndicated Revolver One [Member] Syndicated Revolver One [Member] Syndicated Revolver 2 [Member] Syndicated Revolver Two [Member] Syndicated Revolver Two [Member] Parent [Member] Parent [Member] Lender Name [Axis] Lender Name [Axis] Credit Facility [Domain] Line of Credit Facility, Lender [Domain] Community and Minority Banks [Member] Community and Minority Banks [Member] Community and Minority Banks [Member] Revolving Credit Facility [Member] Revolving Credit Facility [Member] Letter of Credit [Member] Letter of Credit [Member] CitiBank [Member] CitiBank [Member] CitiBank [Member] CIBC [Member] CIBC [Member] CIBC [Member] SUMITOMO [Member] SUMITOMO [Member] SUMITOMO [Member] Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period Three [Member] Debt Instrument, Redemption, Period Three [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Letters of Credit Outstanding, Amount Letters of Credit Outstanding, Amount Bridge Loan Bridge Loan Line of Credit Facility, Current Borrowing Capacity Line of Credit Facility, Current Borrowing Capacity Debt Instrument, Face Amount Debt Instrument, Face Amount Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative [Table] Derivative [Table] Proprietary Trading Activities Gain Loss By Income Statement Location [Axis] Proprietary Trading Activities Gain Loss By Income Statement Location [Axis] The income statement location that the gain/loss on proprietary trading activities could be reported under. Proprietary Trading Activities Income Location [Domain] Proprietary Trading Activities Income Location [Domain] The income statement line descriptions that the gain/loss on proprietary trading activities could be reported under. Interest Rate Swap [Member] Interest Rate Swap [Member] Interest Expense [Member] Interest Expense [Member] Purchased Power And Fuel [Member] Purchased Power And Fuel [Member] Total costs incurred and are directly related to energy commodities and services provided during the reporting period. Operating Revenue [Member] Operating Revenue [Member] This element represents the gains (losses) included in earnings that are recognized in operating revenues. Derivative, by Nature [Axis] Derivative, by Nature [Axis] Derivative, Name [Domain] Derivative, Name [Domain] Derivative [Member] Derivative [Member] Collateral And Netting [Member] Collateral And Netting [Member] Application of netting fair value of derivative assets and derivative liabilities in accordance with the entity's accounting policy as well as the offset against collateral under a master netting arrangement. Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Commodity Contract [Member] Commodity Contract [Member] InterestRateandForeignExchange [Member] InterestRateandForeignExchange [Member] InterestRateandForeignExchange [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Operating Revenue One [Member] Operating Revenue One [Member] This element represents the gains (losses) included in earnings that are recognized in operating revenues. Corporate, Non-Segment [Member] Corporate, Non-Segment [Member] Consolidation, Eliminations [Member] Consolidation, Eliminations [Member] Derivative [Line Items] Derivative [Line Items] Mark-to-market derivative assets (current assets) Interest Rate Derivative Assets Current 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. Interest Rate Derivative Assets Noncurrent Interest Rate Derivative Assets Noncurrent 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 greater than a year, net of the effects of master netting arrangements. Total Interest Rate Mark To Market Derivative Assets Total Interest Rate Mark To Market Derivative Assets Total fair value mark-to-market derivative assets as of the balance sheet date. Interest Rate Derivative Liabilities Current Interest Rate Derivative Liabilities Current 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. Interest Rate Derivative Liabilities Noncurrent Interest Rate Derivative Liabilities Noncurrent 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 greater than a year, net of the effects of master netting arrangements. Total Interest Rate Mark To Market Derivative Liabilities Total Interest Rate Mark To Market Derivative Liabilities Total fair value mark-to-market derivative liabilities as of the balance sheet date. Interest Rate Derivative Fair Value Of Derivative Net Interest Rate Derivative Fair Value Of Derivative Net Fair value as of the balance sheet date of the assets less the liabilities of a derivative or group of derivatives. Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Unrealized Gain (Loss) on Derivatives Unrealized Gain (Loss) on Derivatives Gain (Loss) on Sale of Derivatives Gain (Loss) on Sale of Derivatives Net income attributable to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Average common shares outstanding — basic Weighted Average Number of Shares Outstanding, Basic Potentially dilutive effect of stock options, performance share awards and restricted stock Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Average common shares outstanding — diluted Weighted Average Number of Shares Outstanding, Diluted Earnings Per Share and Equity (Exelon) Earnings Per Share [Text Block] InterestRateAndForeignExchangeContract [Member] InterestRateAndForeignExchangeContract [Member] InterestRateAndForeignExchangeContract [Member] Principal or Proprietary Transactions [Member] Principal or Proprietary Transactions [Member] Proprietary Trading Activities Change In Fair Value Proprietary Trading Activities Change In Fair Value Represents the pre-tax mark-to-market gains or losses of certain purchase and sale contracts due to the change in fair value of the derivative contracts held at the reporting date. These contracts are entered into purely to profit from market prices changes as opposed to hedging an exposure. Proprietary Trading Activities Reclassification To Realized At Settlement Proprietary Trading Activities Reclassification To Realized At Settlement Represents the pre-tax mark-to-market gains or losses of certain purchase and sale contracts due to the recognized change in fair value that was reclassified to realized due to settlement of the derivative during the period. These contracts are entered into purely to profit from market prices changes as opposed to hedging an exposure. Proprietary Trading Activities Gain Loss Net Proprietary Trading Activities Gain Loss Net Net pre-tax mark-to-market gain or loss on derivative contracts that were entered into purely to profit from market prices changes as opposed to hedging an exposure. Commitments And Contingencies Additional Narrative Information [Table] Commitments And Contingencies Additional Narrative Information [Table] Commitments And Contingencies Additional Narrative Information [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves [Domain] Valuation Allowances and Reserves [Domain] Legal Reserve [Member] Legal Reserve [Member] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Pending Litigation [Member] Pending Litigation [Member] Settled Litigation [Member] Settled Litigation [Member] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Asbestos Issue [Member] Asbestos Issue [Member] Telephone Consumer Protection Act Lawsuit [Member] Telephone Consumer Protection Act Lawsuit [Member] Telephone Consumer Protection Act Lawsuit [Member] Commitments And Contingencies Additional Narrative Information [Line Items] Commitments And Contingencies Additional Narrative Information [Line Items] Commitments And Contingencies Additional Narrative Information [Line Items] Continuous Power Interruption [Abstract] Continuous Power Interruption [Abstract] Abstract for regulation related to continuous power interuption under the Illinois Public Utilities Act. Minimum number of customers ComEd can be held liable to for power interruption Minimum Customers Power Interruption The minimum number of customers experiencing four or more hours of power interruption to which utility company can be held liable under state law. Number of customers affected by a major storm Customers Affected By Major Storms The numbers of customers affected by a major storm. Number of customers proposed by the ICC that ComEd should not be granted a waiver under Continuous Power Interruption Number Of Customers Waiver Not Granted Number of customers proposed by the ICC that ComEd should not be granted a waiver under Continuous Power Interruption Telephone Consumer Protection Act Lawsuit [Abstract] Telephone Consumer Protection Act Lawsuit [Abstract] Telephone Consumer Protection Act Lawsuit Loss Contingency, Damages Sought, Value Loss Contingency, Damages Sought, Value Loss Contingency, Estimate [Abstract] Loss Contingency, Estimate [Abstract] Loss Contingency Accrual, Provision Loss Contingency Accrual, Provision Estimated Litigation Liability, Noncurrent Estimated Litigation Liability, Noncurrent Loss Contingency, Pending Claims, Number Loss Contingency, Pending Claims, Number Loss Contingency, Number of Plaintiffs Loss Contingency, Number of Plaintiffs Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Statement [Line Items] Statement [Line Items] Stockholders' Equity Attributable to Parent [Abstract] Stockholders' Equity Attributable to Parent [Abstract] Common Stock, Shares Authorized Common Stock, Shares Authorized Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments Forward Power Basis Forward Power Basis Basis adjustment to the forward power price to deliver at an illiquid location. Forward Gas Basis Forward Gas Basis Basis adjustment to the forward gas price to deliver at an illiquid location Unrecorded Unconditional Purchase Obligation [Table] Unrecorded Unconditional Purchase Obligation [Table] Unrecorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Unrecorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Other Purchase Obligations [Member] Other Purchase Obligations [Member] Unrecorded Unconditional Purchase Obligation [Line Items] Unrecorded Unconditional Purchase Obligation [Line Items] Total Unrecorded Unconditional Purchase Obligation 2015 Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months 2016 Unrecorded Unconditional Purchase Obligation, Due within Two Years 2017 Unrecorded Unconditional Purchase Obligation, Due within Three Years 2018 Unrecorded Unconditional Purchase Obligation, Due within Four Years 2019 Unrecorded Unconditional Purchase Obligation, Due within Five Years Thereafter Unrecorded Unconditional Purchase Obligation, Due after Five Years Regulated Operations [Abstract] Regulatory Matters Additional Narrative Information [Table] Regulatory Matters Additional Narrative Information [Table] Regulatory Liability [Axis] Regulatory Liability [Axis] Regulatory Liability [Domain] Regulatory Liability [Domain] Over Recovered Energy And Transmission Costs [Member] Over Recovered Energy And Transmission Costs [Member] Represents the over-recovered (regulatory liability) purchased power and/or gas supply related costs refundable to customers. An over recovery means that the actual costs of electricity or natural gas realized by the regulated utility were less than the rates charged to customers during the period and are refundable to customers. Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Scenario, Forecast [Member] Scenario, Forecast [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Regulatory Agency [Axis] Regulatory Agency [Axis] Regulatory Agency [Domain] Regulatory Agency [Domain] FERC Transmission Complaint [Member] FERC Transmission Complaint [Member] FERC Transmission Complaint [Member] Regulatory Asset [Axis] Regulatory Asset [Axis] Regulatory Asset [Domain] Regulatory Asset [Domain] Under Recovered Distribution Service Costs [Member] Under Recovered Distribution Service Costs [Member] Represents the under-recovered (regulatory asset) distribution service costs recoverable from customers. An under recovery means that the actual costs of distributing electricity realized by the regulated utility were more than the rates charged to customers during the period and are recoverable from customers. AMI Expenses [Member] AMI Expenses [Member] Represents costs incurred related to the state utility commission approved advanced metering infrastructure program. Energy Efficiency And Demand Response Programs [Member] Energy Efficiency And Demand Response Programs [Member] Costs related to energy efficiency and demand response programs recorded to a regulatory asset Transmission Rate Formula [Member] Transmission Rate Formula [Member] Transmission Rate Formula [Member] Distribution formula Rate [Member] Distribution formula Rate [Member] Distribution formula Rate [Member] Stride Program [Member] Stride Program [Member] Stride Program [Member] Under-Recovered Electric Supply Costs [Member] Under-Recovered Electric Supply Costs [Member] Under-Recovered Electric Supply Costs [Member] Under Recovered Energy And Transmission Costs [Member] Under Recovered Energy And Transmission Costs [Member] Represents the under-recovered (regulatory asset) purchased power and/or gas supply related costs recoverable from customers. An under recovery means that the actual costs of electricity or natural gas realized by the regulated utility were more than the rates charged to customers during the period and are recoverable from customers. Renewable Energy Requirement [Member] Renewable Energy Requirement [Member] Renewable Energy Requirement [Member] Regulatory Asset Liability [Axis] Regulatory Asset Liability [Axis] Presents the name of the regulatory assets and liabilities itemized in a table of regulatory current or noncurrent assets and liabilities. Regulatory Matters Additional Narrative Information [Line Items] Regulatory Matters Additional Narrative Information [Line Items] Regulatory Matters Additional Narrative Information [Line Items] Regulatory Assets Regulatory Assets Rate of Return on Common Equity, Incentive Basis Points Rate of Return on Common Equity, Incentive Basis Points Rate of Return on Common Equity, Incentive Basis Points Net regulatory asset Net Regulatory Asset Net under recoveries of costs to be reimbursed by customers resulting in a regulatory asset. Spend on smart grid investments Projected Investment In Smart Grid Infrastructure Projected Investment In Smart Grid Infrastructure Public Utilities, Requested Rate Increase (Decrease), Amount Public Utilities, Requested Rate Increase (Decrease), Amount Expected revenue adjustment for current year Current Year Revenue Adjustment Exepected adjustment to revenue related to the current year. Expected revenue adjustment for prior year Prior Year Revenue Adjustment Exepected adjustment to revenue to be recorded in the prior year. Requested Debt and Equity Return on Distribution Public Utilities, Requested Equity Capital Structure, Percentage Requested ROE Public Utilities, Requested Return on Equity, Percentage Weighted Average Debt And Equity Return Electric Distribution Weighted Average Debt And Equity Return Electric Distribution The weighted average debt and equity return on electric distribution rate base that a utility is authorized to recover through regulated rates for a specific period. Weighted Average Debt And Equity Return Weighted Average Debt And Equity Return The weighted average debt and equity return on transmission rate base that a utility is authorized to recover through regulated rates for a specific period. Public Utilities, Interim Rate Increase (Decrease), Amount Public Utilities, Interim Rate Increase (Decrease), Amount Approved Debt and Equity Rate on Distribution Public Utilities, Approved Equity Capital Structure, Percentage Approved ROE Public Utilities, Approved Return on Equity, Percentage ICC Approved Rate Increase (Decrease), Amount Public Utilities, Approved Rate Increase (Decrease), Amount Demand response peak demand reduction Annual Demand Response Reduction Required reduction in peak energy demand under State program. Requested increase in electric revenues Electric Revenues Increase Requested Electric delivery service revenue increase requested by a utility through a rate case proceeding with state regulators, which is pending approval. Adjustment to Requested increase in electric revenues Adjustment To Electric Revenues Increase Requested Estimated adjustment to electric delivery service revenue requirement increase requested by a utility through a rate case proceeding with state regulators. Requested increase in gas revenues Gas Revenues Increase Requested Gas delivery service revenue increase requested by a utility through a rate case proceeding with state regulators, which is pending approval. Rate of return on common equity electric distribution Rate Of Return Common Equity Electric Distribution Rate of return on common equity electric distribution Rate of return on common equity gas distribution Rate Of Return Common Equity Gas Distribution Rate of return on common equity gas distribution Increase in electric delivery service revenue resulting from rate case settlement or order. Electric Revenues Increase Settlement Utility electric delivery service revenue increase resulting from a rate case settlement with interested parties, which is subject to state utility commission approval or order. Increase in gas delivery service revenue resulting from rate case settlement or order. Gas Revenues Increase Settlement Utility gas delivery service revenue increase resulting from a rate case settlement with interested parties, which is subject to state utility commission approval or order. Annual Depreciation Expense Decrease Regulated Property Annual Depreciation Expense Decrease Regulated Property Annual Depreciation Expense Decrease Regulated Property Requested Rate Of Return Common Equity Gas Distribution Requested Rate Of Return Common Equity Gas Distribution Gross transmission revenue requirement Gross transmission revenue requirement The total transmission revenue requirement for a specific period that a utility is authorized to recover through regulated rates, which includes operating expenses and a return on rate base. Transmission revenue true up Transmission revenue true up Adjustment made to a utility's transmission revenue requirement for a specific period as a result of a true-up of actual costs for the specific period. Net transmission revenue requirement Net transmission revenue requirement The total transmission revenue requirement for a specific period net of a true-up of actual costs incurred from the prior year, which includes operating expenses and a return on rate base. Net Regulatory Assets Net Regulatory Assets Net Regulatory Asset Regulatory Rate of Return Approved Public Utilities, Approved Rate Increase (Decrease), Percentage Public Utilities, Interim Rate Increase (Decrease), Percentage Public Utilities, Interim Rate Increase (Decrease), Percentage Public Utilities, Requested Rate Increase (Decrease), Percentage Public Utilities, Requested Rate Increase (Decrease), Percentage Revenue Reduction Revenue Reduction Revenue Reduction Customer Refund Liability, Noncurrent Customer Refund Liability, Noncurrent Estimated number of smart meters to be installed Estimated Smart Meters Estimated number of smart meters to be installed to comply with state law, which requires for utility to install smart meters for all customers. TotalSmartMetersInstalled TotalSmartMetersInstalled TotalSmartMetersInstalled Smart Meters Installed Smart Meters Installed The number of smart meters installed under a pilot program approved by a state utility regulator. Revised spend on its Smart Meter Procurement and Installation Plan Projected Investment In Smartmeters Projected Investment In Smartmeters Requested Rate Of Return Common Equity Electric Distribution Requested Rate Of Return Common Equity Electric Distribution SmartMeterFundingSGIG SmartMeterFundingSGIG SmartMeterFundingSGIG Smart meter spend to date Total Smartmeter Spend On Investment Total Smartmeter Spend On Investment Smart grid infrastructure spend to date Total Smart Grid Spend On Investment Total Smart Grid Spend On Investment Total smart grid and smart meter investment grant amount Total Smart Grid Smart Meter Investment Grant Awarded Grant that was awarded to the utility under a smart grid program by the Department of Energy. Smart meter investment grant awarded Smart Meter Investment Grant Awarded Grant that was awarded to the utility under a smart grid program for smart meters with the Department of Energy. Smart grid investment grant awarded Smart Grid Investment Grant Awarded Grant that was awarded to the utility for smart grid investments from the Department of Energy. Reimbursements received from the DOE Doe Reimbursements Reimbursements received from the DOE related to the SGIG. Regulatory assets Regulatory Assets, Noncurrent Regulatory assets for original smart meters purchased Regulatory Assets For Original Smart Meters Purchased Regulatory asset established for the amount of the original meters, net of accumulated depreciation and DOE reimbursements Vendor Refund Vendor Refund Vendor Refund Amount of reimbursements received from the DOE applied to the originally installed Smart Meters. Doe Reimbursements Use For Original Meter Installment Amount of reimbursements received from the DOE related to the SGIG that were applied by the Utility towards the Smart Meters it originally installed. Total Projected smart meter smart grid spend Total Project Smart Meter Smart Grid Spend Projected total spend on PECO's smart grid and smart meter infrastructure Current Year AMI Events Balance Current Year AMI Events Balance Depreciation Related To Original Meters Depreciation Related To Original Meters Depreciation Related To Original Meters DOE Cash Payable to Sub Recipients Accounts Payable, Other, Current Upfront fee for opt-out of Smart Meter Upfront Fee Upfront fee Recurring Fees Recurring Fee Recurring Fee Cumulative Consumption Reduction Targets Cumulative Consumption Reduction Targets Cumulative consumption reduction targets (as a percentage) of the Energy Efficiency Program over a period of three years. Proposed funding of estimated costs associated with DLC demand program due to modification of incentive levels for other Phase II programs. Proposed Funding Of Direc Load Control Program Costs Amount of proposed funding by utility for estimated cost related to its state sponsored Direct Load Control Demand Reduction Program as a result of modifying incentive levels for other Phase II programs. Customer Refund Cash Collected Customer Refundable Fees, Refund Payments Rate Of Return On Common Equity Rate Of Return On Common Equity The rate of return on common equity that a utility is authorized to recover through regulated rates. Common Equity Component Cap Common Equity Component Cap The cap placed by the regulator on the common equity component of the ratio used to determine the weighted average debt and equity return on transmission rate base for a utility. Capital and OM estimates current year Captial and OM estimates current year Captial and O&M estimates current year Revenue Requirement Revenue Requirment Revenue Requirment Minimum Purchase Obligation Minimum Purchase Obligation Maximum Purchase Obligation Maximum Purchase Obligation License Costs License Costs Rate Of Return On Common Equity In Federal Energy Regulatory Committee Complaint Rate Of Return On Common Equity In Federal Energy Regulatory Committee Complaint The rate of return on common equity that a utility is authorized to recover through regulated rates proposed in the FERC transmission complaint. Transmission Rate Formula, First Basis Points Credited Transmission Rate Formula, First Basis Points Credited Transmission Rate Formula, First Basis Points Credited Amount of Regulatory Costs Not yet Approved Amount of Regulatory Costs Not yet Approved Other Commitment Other Commitment CostRecoveryForSignificantOneTimeEvents CostRecoveryForSignificantOneTimeEvents CostRecoveryForSignificantOneTimeEvents UnderOverRecoveredDistributionServiceCosts UnderOverRecoveredDistributionServiceCosts UnderOverRecoveredDistributionServiceCosts ElectricTransmissionCostsUnderRecovery ElectricTransmissionCostsUnderRecovery ElectricTransmissionCostsUnderRecovery Business Combination, Integration Related Costs Business Combination, Integration Related Costs RegulatoryAssetsDueToDeferredStormCosts RegulatoryAssetsDueToDeferredStormCosts RegulatoryAssetsDueToDeferredStormCosts Regulatory Liabilities Regulatory Liabilities Total Projected Natural Gas LTIIP Spend Total Projected Natural Gas LTIIP Spend Total Projected Natural Gas LTIIP Spend Income Statement [Abstract] Operating revenues [Abstract] Revenues [Abstract] Operating revenues Electrical Generation Revenue Operating revenues Electrical Transmission and Distribution Revenue Operating revenues Electric and Gas Revenue Operating revenues from affiliates Total Revenues Operating expenses Costs and Expenses [Abstract] Purchased power and fuel from affiliates Cost Of Goods And Services Energy Commodities And Services From Affiliate Total costs incurred and are directly related to energy commodities and services provided during the reporting period from affiliate. Purchased power and fuel Cost of Goods and Services, Energy Commodities and Services Purchased power and fuel Cost of Purchased Power Purchased power and fuel from affiliates Cost Of Purchased Power Affiliate Cost of electricity purchased and sold during the reporting period from affiliate. Operating and maintenance Other Cost and Expense, Operating Operating and maintenance from affiliates Related Party Transaction, Expenses from Transactions with Related Party Depreciation and amortization Other Depreciation and Amortization Taxes other than income Taxes, Miscellaneous Total operating expenses Costs and Expenses Equity in losses of unconsolidated affiliates Income (Loss) from Equity Method Investments Gain (Loss) on Sale of Assets and Asset Impairment Charges Gain (Loss) on Sale of Assets and Asset Impairment Charges Gain (Loss) on Disposition of Assets Gain (Loss) on Disposition of Assets Gain on consolidation and acquisition of businesses Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss), Net Operating income Operating Income (Loss) Other income and (deductions) Nonoperating Income (Expense) [Abstract] Interest expense, net Interest Expense Interest expense to affiliates Interest Expense, Related Party Other, net Other Nonoperating Income (Expense) Total other income and (deductions) Nonoperating Income (Expense) Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Domestic Income taxes Income Tax Expense (Benefit) Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Net income Preferred security dividends and redemption Dividends, Preferred Stock Net income (loss) attributable to noncontrolling interests Income (Loss) Attributable to Noncontrolling Interest Net income (loss) attributable to noncontrolling interest and preference stock dividends Net Income Loss Attributable To Noncontrolling Interest And Preferred Stock Dividends And Other Adjustments The portion of net income (loss) attributable to the noncontrolling interest (if any) deducted in order to derive the portion attributable to the parent combined with the aggregate value of preferred stock dividends and other adjustments necessary to derive net income apportioned to common stockholders. Net income attributable to membership interest Income (Loss), Including Portion Attributable to Noncontrolling Interest Net income attributable to common shareholders Other comprehensive income (loss), net of income taxes Other Comprehensive Income (Loss), Net of Tax [Abstract] Pension and non-pension postretirement benefit plans: Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract] Prior service benefit reclassified to periodic benefit cost Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Net of Tax Actuarial loss reclassified to periodic cost Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Net of Tax Pension and non-pension postretirement benefit plans valuation adjustment Other Comprehensive Income (Loss), Finalization of Pension and Other Postretirement Benefit Plan Valuation, Net of Tax Deferred Compensation Unit Valuation Adjustment Deferred Compensation Unit Valuation Adjustment Unrealized gain (loss) on cash flow hedges Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Unrealized gain (loss) on equity investments Other Comprehensive Income Unrealized Income Loss On Equity Investments Arising During Period Net Of Tax Change in accumulated income and losses from certain equity investments during the period being reported on, net of tax. Unrealized gain (loss) on foreign currency translation Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Unrealized loss on marketable securities Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Reversal of CENG equity method AOCI OtherComprehensiveIncomeLossNetOfTaxPeriodDecrease OtherComprehensiveIncomeLossNetOfTaxPeriodDecrease Other comprehensive income (loss) Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Average shares of common stock outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Average common shares outstanding — diluted Earnings per average common share: Earnings Per Share, Basic [Abstract] Earnings per share - basic (in usd per share) Earnings Per Share, Basic Earnings per average common share - diluted Earnings Per Share, Diluted [Abstract] Earnings per share - diluted (in usd per share) Earnings Per Share, Diluted Dividends per common share (in usd per share) Common Stock, Dividends, Per Share, Cash Paid Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net Mark-to-market derivative assets (current assets) Derivative Asset, Current Mark-to-market derivative assets Derivative Asset, Noncurrent Total mark-to-market derivative net assets (liabilities) Derivative, Fair Value, Net Total mark-to-market derivative assets Derivative Liability Unrealized Losses On Nuclear Decommissioning Trust Fund Investment [Table] Unrealized Losses On Nuclear Decommissioning Trust Fund Investment [Table] A table providing unrealized gains/losses on nuclear decommissioning trust funds and other-than-temporary impairment of nuclear decommissioning trust funds. Unrealized Losses On Nuclear Decommissioning Trust Fund Investment [Line Items] Unrealized Losses On Nuclear Decommissioning Trust Fund Investment [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Net unrealized gains (losses) on decommissioning trust funds - regulatory agreement units Unrealized Gain Loss Investment Income Nuclear Decommissioning Trust Funds Regulatory Accounting This item represents unrealized gains (losses) for the period as a result of holding marketable securities held in nuclear decommissioning trust funds and classified as trading securities. As a result of certain regulatory agreements for these nuclear decommissioning trust funds; upon completion of decommissioning activities, excess (shortfall of) funds will be refunded to (recovered from) rate payers through a regulated affiliate. Therefore, this activity is contractually eliminated within the income statement. Net unrealized gains (losses) on decommissioning trust funds - non-regulatory agreement units Unrealized Gain Loss Investment Income Nuclear Decommissioning Trust Funds NonRegulatory Accounting This item represents unrealized gains (losses) included in earnings for the period as a result of holding marketable securities held in nuclear decommissioning trust funds and classified as trading securities. Unrealized Gain Loss Investment Income Pledged Assets Unrealized Gain Loss Investment Income Pledged Assets Unrealized Gain Loss Investment Income on Zion Station Pledged Assets Restructuring and Related Activities [Abstract] Schedule Of Corporate Restructuring Severance Benefit Obligation [Table] Schedule Of Corporate Restructuring Severance Benefit Obligation [Table] Corporate Restructuring Severance Benefit Obligation [Line Items] Corporate Restructuring Severance Benefit Obligation [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Severance charges recorded Severance Obligation Severance Charges Amount charged against earnings in the period for a specified incurred and estimated severance cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan. Supplemental Financial Information [Abstract] Supplemental Financial Information [Abstract] Supplemental Income Statement Information [Table] Schedule disclosing additional information about a registrants statement of operations. Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification out of Accumulated Other Comprehensive Income [Member] Supplemental Income Statement Information [Line Items] Supplemental Income Statement Information [Line Items] Supplemental Income Statement Information Abstract Other, Net [Abstract] Other Nonoperating Income (Expense) [Abstract] Decommissioning-Related Activities [Abstract] Gain Loss On Nuclear Decommissioning Trust Fund Investments [Abstract] Gain / loss on nuclear decommissioning trust fund investments abstract. Net realized income on decommissioning trust funds - Regulatory Agreement Units Realized Gain Loss Investment Income Nuclear Decommissioning Trust Funds Regulatory Accounting This item represents investment income and realized gains (losses) for the period as a result of selling marketable securities held in nuclear decommissioning trust funds and classified as trading securities. As a result of certain regulatory agreements for these nuclear decommissioning trust funds; upon completion of decommissioning activities, excess (shortfall of) funds will be refunded to (recovered from) rate payers through a regulated affiliate. Therefore, this activity is contractually eliminated within the income statement. Net realized income on decommissioning trust funds - Non-Regulatory Agreement Units Realized Gain Loss Investment Income Nuclear Decommissioning Trust Funds Nonregulatory Accounting This item represents investment income and realized gains (losses) for the period as a result of selling marketable securities held in nuclear decommissioning trust funds classified as trading securities. Net unrealized income (losses) on decommissioning trust funds - Regulatory Agreement Units Unrealized Gain Loss Nuclear Decommissioning Trust Funds Regulatory Accounting This item represents unrealized gains (losses) for the period as a result of holding marketable securities held in nuclear decommissioning trust funds and classified as trading securities. As a result of certain regulatory agreements for these nuclear decommissioning trust funds; upon completion of decommissioning activities, excess (shortfall of) funds will be refunded to (recovered from) rate payers through a regulated affiliate. Therefore, this activity is contractually eliminated within the income statement. Net unrealized income (losses) on decommissioning trust funds - Non-Regulatory Agreement Unrealized Gain Loss Nuclear Decommissioning Trust Funds Nonregulatory Accounting This item represents unrealized gains (losses) included in earnings for the period as a result of holding marketable securities held in nuclear decommissioning trust funds and classified as trading securities. Net unrealized income (losses) on pledged assets Net Unrealized Gain Loss On Pledged Assets Net unrealized losses on pledged assets associated with the decommissioning of a nuclear generating facility. Regulatory offset to decommissioning trust fund-related activities Regulatory Offset Nuclear Decommissioning Trust Fund Activity This item represents the contractual elimination of nuclear decommissioning trust fund-related activity, which may include realized income (losses), unrealized income (losses), asset retirement obligation accretion, asset retirement cost amortization, investment income and related income taxes. As a result of certain regulatory agreements for these nuclear decommissioning trust funds; upon completion of decommissioning activities, excess (shortfall of) funds will be refunded to (recovered from) rate payers through a regulated affiliate. Therefore, this activity is contractually eliminated within the income statement. Total decommissioning-related activities Gain Loss Investment Income Nuclear Decommissioning Trust Funds This item represents the total investment income and realized and unrealized gains (losses) included in earnings for the period as a result of selling and holding marketable securities held in nuclear decommissioning trust funds and classified as trading securities. Investment income Investment Income, Interest Long-term lease income Capital Leases, Income Statement, Direct Financing Lease Revenue Interest income related to uncertain income tax positions Unrecognized Tax Benefits Interest Income This element represents interest income recognized for an overpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity. AFUDC - equity Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Other Income Other Nonoperating Income Other, net Compensation and Retirement Disclosure [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Pension Plan, Defined Benefit [Member] Pension Plan [Member] Other Postretirement Benefit Plan, Defined Benefit [Member] Other Postretirement Benefit Plan [Member] Business Services Company [Member] Business Services Company [Member] Business Services Company. Constellation Energy Nuclear Group [Member] Constellation Energy Nuclear Group [Member] Represents a joint venture relating to a nuclear generation and operation business. Defined Benefit Plan Legacy [Axis] Defined Benefit Plan Legacy [Axis] Defined benefit plan legacy axis Defined Benefit Plan Legacy [Domain] Defined Benefit Plan Legacy [Domain] Exelon Legacy Benefit Plans [Member] Exelon Legacy Benefit Plans [Member] Pension and other postretirement plans established under Exelon prior to the merger with Constellation. CENG [Member] CENG [Member] Represents a joint venture relating to a nuclear generation and operation business. Exelon Sponsored Benefit Plan [Member] Exelon Sponsored Benefit Plan [Member] Exelon Sponsored Benefit Plan [Member] Remeasurement [Axis] Remeasurement [Axis] Represents Remeasurement of defined benefit pension and post retirement benefit obligation Remeasurement [Domain] Remeasurement [Domain] Represents Remeasurementt for defined benefit pension and post retirement benefit obligation Remeasurement [Member] Remeasurement [Member] Represents valuation adjustment for defined benefit pension and post retirement benefit obligation Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Defined Contribution Plan Name [Axis] Defined Contribution Plan Name [Axis] Defined Contribution Plan Name [Domain] Defined Contribution Plan Name [Domain] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Benefit obligation increase (decrease) reflecting actual census data Defined Benefit Plan Valuation Adjustment Increase (decrease) in defined benefit obligation due to an updated valuation reflecting actual census data. Changes in plan assets and benefit obligations recognized in OCI Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Before Tax The aggregate net gain or loss and net prior service cost or credit recognized in other comprehensive income, including amounts arising during the period and reclassification adjustments of other comprehensive income as a result of being recognized as components of net periodic benefit cost for the period. Increase in regulatory assets due valuation received by Exelon for its legacy pension and other postretirement benefit obligations. Defined Benefit Plan Amounts Recognized In Regulatory Assets Before Tax The aggregate net gain or loss and net prior service cost or credit recognized in regulatory assets, including amounts arising during the period and reclassification adjustments of regulatory assets as a result of being recognized as components of net periodic benefit cost for the period. Increase in regulatory liabilities due to updated valuation of Exelon's legacy pension and postretirement benefit obligations Defined Benefit Plan Amounts Recognized In Regulatory Liabilities Before Tax Increase in regulatory liabilities due to updated valuation received by Exelon for its legacy pension and other postretirement benefit obligations. Pension Obligations Valuation Adjustment Increase (Decrease) in Pension Plan Obligations Other postretirement benefit obligation increase (decrease) due to updated valuation adjustment Defined Benefit Plan Other Postretirement Benefit Obligation Update Pension Opeb The net increase or decrease in the other postretirement benefit obligation due to the increase or decrease in the value of either the benefit obligation or the plan assets resulting from annual census data used in actuarial assumption. Regulatory asset increase (decrease) due to updated valuation adjustment Defined Benefit Plan Regulatory Asset Liability Census Update Pension Opeb The net increase or decrease in the regulatory asset due to the increase or decrease in the value of either the benefit obligation or the plan assets resulting from annual census data used in actuarial assumption. Pension And Other Postretirement Benefit Expense Included In Capital And Operating And Maintenance Expense Pension And Other Postretirement Benefit Expense Included In Capital And Operating And Maintenance Expense The amount of pension and other (such as medical, dental and life insurance) postretirement benefit costs included in capital and operating and maintenance expense that was recognized during the period for defined benefit plans (periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain or loss on assets, prior service cost or credit, transition asset or obligation, and gain or loss due to settlements or curtailments). Regulatory Asset increase (decrease) due to design changes Defined Benefit Plan Regulatory Asset Liability Design Change Opeb Increase (decrease) in regulatory asset due to design changes. Other comprehensive income (loss) due to design changes Other Comprehensive Income Defined Benefit Plans Design Changes Net Of Tax The increase (decrease) in accumulated comprehensive income during the period related to design changes of other postretirement benefit plans, after tax. While for technical reasons this element has no balance attribute, the default assumption is a credit balance consistent with its label. Expected return on assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets Discount rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Expected qualified pension plan contributions Qualified Defined Benefit Plan Estimated Future Employer Contributions In Next Fiscal Year The employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the qualified pension plan during the next fiscal year beginning after the date of the latest statement of financial position. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions. Expected non-qualified pension plan contributions Non Qualified Defined Benefit Plan Estimated Future Employer Contributions In Next Fiscal Year The employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the non-qualified pension plan during the next fiscal year beginning after the date of the latest statement of financial position. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions. Expected other postretirement benefit plan contributions Defined Other Postretirement Benefit Plan Estimated Future Employer Contributions In Next Fiscal Year The employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the other postretirement benefit plan during the next fiscal year beginning after the date of the latest statement of financial position. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions. Major classes of assets and liabilities held for sale Disclosure of Long Lived Assets Held-for-sale [Table Text Block] Summary of the derivative fair value Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] The activity of accumulated OCI related to cash flow hedges Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block] Other Derivatives - Gain (loss) and reclassification Schedule Of Other Derivatives [Text Block] This table provides details on contracts that do not qualify or are not designated for hedge accounting. These instruments represent economic hedges that mitigate exposure to fluctuations in commodity prices and include financial options, futures, swaps, and forward sales. Information on Generation's credit exposure for all derivative instruments, normal purchase normal sales, and applicable payables and receivables, net of collateral and instruments that are subject to master netting agreements Schedule Of Credit Risk [Table Text Block] Table format of information on the sources of credit risk exposure faced by the entity for all derivative instruments and detail of credit exposure by type of counterparty Disclosure of Credit Derivatives [Table Text Block] Disclosure of Credit Derivatives [Table Text Block] Variable Interest Entity [Abstract] Variable Interest Entity [Abstract] Variable Interest Entities (Exelon, Generation, ComEd, PECO and BGE) Variable Interest Entities Disclosure [Text Block] Common Stock [Abstract] Common Stock [Abstract] Common Stock (Exelon, Generation, ComEd, PECO and BGE) Common Stock [Text Block] Level 1 Text block concept for equity and debt transaction issued in connection with the PHI merger Reclassification out of Accumulated Other Comprehensive Income [Table] Equity Method Investments Equity Method Investments [Member] Energy Related Derivative [Member] Energy Related Derivative [Member] Cash Flow Hedging [Member] Cash Flow Hedging [Member] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Income before income taxes Income taxes Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest Prior service benefit reclassified to periodic benefit cost Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Tax Other Nonoperating Income (Expense) Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax Gain on consolidation of CENG Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain Interest Expense Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Convertible Debt Securities [Member] Convertible Debt Securities [Member] First Mortgage Bonds [Member] First Mortgage Bonds [Member] Bonds that are backed by the first claim on the proceeds from the sale of a specific asset or set of assets in the event that the company is liquidated. Senior Notes [Member] Senior Notes [Member] Unsecured Debt [Member] Unsecured Debt [Member] Subordinated Debt [Member] Subordinated Debt [Member] Notes Payable, Other Payables [Member] Notes Payable, Other Payables [Member] ExgenRenewables425February62021 [Member] ExgenRenewables425February62021 [Member] ExgenRenewables425February62021 [Member] ExGen Texas Power [Member] ExGen Texas Power [Member] ExGen Texas Power [Member] Energy Efficiency Project Financing [Member] Energy Efficiency Project Financing [Member] Documentation to be provided EnergyEfficiency355Nov152016 [Member] EnergyEfficiency355Nov152016 [Member] EnergyEfficiency355Nov152016 [Member] TaxExemptBonds255 [Member] TaxExemptBonds255 [Member] TaxExemptBonds255 [Member] AVSR [Member] AVSR [Member] AVSR [Member] NuclearFuelPurchaseContract3250june302018Member [Member] NuclearFuelPurchaseContract3250june302018Member [Member] NuclearFuelPurchaseContract3250june302018Member [Member] FirstMortgageBondSeries115January152019 [Member] FirstMortgageBondSeries115January152019 [Member] FirstMortgageBondSeries115January152019 [Member] FirstMortgageBondSeries116January152044 [Member] FirstMortgageBondSeries116January152044 [Member] FirstMortgageBondSeries116January152044 [Member] FirstAndRefundingMortageBondsOctoberu12044 [Member] FirstAndRefundingMortageBondsOctoberu12044 [Member] FirstAndRefundingMortageBondsOctoberu12044 [Member] Continental Wind 6000 February 28, 2033 [Member] Continental Wind 6000 February 28, 2033 [Member] FirstMortgageBondSeries114August152043 [Member] [Member] FirstMortgageBondSeries114August152043 [Member] [Member] FirstMortgageBondSeries114August152043 [Member] [Member] FirstAndRefundMortgageBondOctober152016 [Member] FirstAndRefundMortgageBondOctober152016 [Member] FirstAndRefundMortgageBondOctober152016 [Member] FirstAndRefundMortgageBondOctober152043 [Member] FirstAndRefundMortgageBondOctober152043 [Member] FirstAndRefundMortgageBondOctober152043 [Member] SeniorNotesJuly12023Member [Member] SeniorNotesJuly12023Member [Member] SeniorNotesJuly12023[Member] FirstMortgageBondSeries118March12045 [Member] FirstMortgageBondSeries118March12045 [Member] FirstMortgageBondSeries118March12045 [Member] FirstMortgageBond101 [Member] FirstMortgageBond101 [Member] FirstMortgageBond101 [Member] JuniorNotes250June012024 [Member] JuniorNotes250June012024 [Member] JuniorNotes250June012024 [Member] ExGen425Feb062021 [Member] ExGen425Feb062021 [Member] ExGen425Feb062021 [Member] MergerDebt155June092017 [Member] MergerDebt155June092017 [Member] MergerDebt155June092017 [Member] MergerDebt285June152020 [Member] MergerDebt285June152020 [Member] MergerDebt285June152020 MergerDebt395June152025 [Member] MergerDebt395June152025 [Member] MergerDebt395June152025 [Member] MergerDebt495June152035 [Member] MergerDebt495June152035 [Member] MergerDebt495June152035 [Member] MergerDebt510June152045 [Member] MergerDebt510June152045 [Member] MergerDebt510June152045 [Member] SoftwareLicense395May012024 [Member] SoftwareLicense395May012024 [Member] SoftwareLicense395May012024 [Member] AGE143Nov172017 [Member] AGE143Nov172017 [Member] AGE143Nov172017 [Member] Long-term Debt Long-term Debt Interest Rate Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Redemption Price, Percentage Debt Instrument, Redemption Price, Percentage Unamortized Debt Issuance Expense Unamortized Debt Issuance Expense Schedule of Defined Benefit Plans Disclosures [Table] Regulatory Assets [Member] Regulatory Assets [Member] Carrying amount as of the balance sheet date of regulatory assets which are not elsewhere specified in the taxonomy. Savings Plan Matching Contributions Defined Benefit Plan, Contributions by Employer Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on assets Defined Benefit Plan, Expected Return on Plan Assets Amortization of: Amortization of Prior Service Cost (Benefit) and Actuarial Loss [Abstract] Amortization of Prior Service Cost (Benefit) and Actuarial Loss [Abstract] Prior service cost (benefit) Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Actuarial loss Defined Benefit Plan, Amortization of Gains (Losses) Net periodic benefit cost Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements Net periodic benefit cost Defined Benefit Plan, Net Periodic Benefit Cost Pension and Other Postretirement Benefit Costs Pension and Other Postretirement Benefit Expense Pension and Other Postretirement Benefit Expense Regulatory Matters (Exelon, Generation, ComEd, PECO and BGE) Public Utilities Disclosure [Text Block] Commitments And Contingencies Tables Disclosure [Table] Commitments And Contingencies Tables Disclosure [Table] Investment [Axis] Investment [Axis] Investment [Domain] Investment [Domain] Equity Method Investments [Member] Commitments And Contingencies Tables Disclosure [Line Items] Commitments And Contingencies Tables Disclosure [Line Items] Energy Commitments Energy Commitments [Table Text Block] Disclosures of short- and long-term energy-related commitments over the next five years and beyond. Types of energy-related commitments include the purchase from and sale to unaffiliated utilities and others of energy, capacity and transmission rights. Data is presented by year and in total. Utility Energy Purchase Commitments Utility Energy Purchase Commitments [Table Text Block] Disclosures of short- and long-term energy-related purchase commitments, including renewable energy credits, by an electric utility company over the next five years and beyond. Data is presented by year and in total. Fuel Purchase Commitments Fuel Purchase Commitments [Table Text Block] Disclosures of short- and long-term fuel purchase commitments over the next five years and beyond. Types of fuel disclosed include nuclear fuel, natural gas and coal. Data is presented by year and in total. Other Purchase Obligation Other Purchase Obligation [Table Text Block] Disclosures of short- and long-term other purchase obligations, over the next five years. Data is presented by year and in total. Other Commitments Other Commitments [Table Text Block] Commercial Commitments Commercial Commitments [Table Text Block] Disclosures of short- and long-term commitments potentially triggered by future events, over the next five years and beyond. Data is presented by year and in total. Accrued environmental liabilities Schedule of Environmental Loss Contingencies by Site [Table Text Block] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Bridge Loan [Member] Bridge Loan [Member] SeniorSecuredNotes525January152014Member [Member] SeniorSecuredNotes525January152014Member [Member] Long Term Debt issued Senior Secured Notes 5.25% interest rate due January152014 SeniorNotesJan152020 [Member] SeniorNotesJan152020 [Member] SeniorNotesJan152020[Member] ExgenRenewablesI425June62021[Member] ExgenRenewablesI425June62021[Member] Long Termm Debt Issued ExgenRenewablesI 4.25% due June 6 2021 MergerDebt [Member] MergerDebt [Member] MergerDebt [Member] Secured Debt [Member] Secured Debt [Member] Senior Loans [Member] Senior Loans [Member] Junior Subordinated Debt [Member] Junior Subordinated Debt [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Standby Letters of Credit [Member] Standby Letters of Credit [Member] Parent Company [Member] Parent Company [Member] ExGen Texas Power, LLC [Member] ExGen Texas Power, LLC [Member] ExGen Texas Power, LLC [Member] ExGen Renewables I, LLC [Member] ExGen Renewables I, LLC [Member] Exgen renewable LLC an indirect subsidiary of Exelon and Generation Repayments of Long-term Debt Repayments of Long-term Debt Amount Of Aggregate Letters of Credit Available Amount Of Aggregate Letters of Credit Available The aggregate amount of letters of credit that may be issued under the unsecured revolving credit facility. Line of Credit Facility, Expiration Date Line of Credit Facility, Expiration Date Additional Amount of Aggregate Letters of Credit Available Additional Amount of Aggregate Letters of Credit Available Additional Amount of Aggregate Letters of Credit Available Outstanding borrowings/facility draws Long-term Line of Credit Line of Credit Facility, Remaining Borrowing Capacity Line of Credit Facility, Remaining Borrowing Capacity Basis points adders for prime-based borrowings Basis Points For Prime Based Borrowings Maximum basis points that can be added to borrowings at prime rate, actual basis points depends on credit rating. Basis Points For Libor Based Borrowings Basis Points For Libor Based Borrowings Maximum basis points that can be added to borrowings at LIBOR, actual basis points depends on credit rating. Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum Interest Expense, Commercial Paper Interest Expense, Commercial Paper Subordinated Debt, Amount Subordinated Long-term Debt, Noncurrent equity units issued Equity Units Issued Junior subordinate notes issued in the form of equity units Shares Issued, Price Per Share Shares Issued, Price Per Share Proceeds from Issuance of Subordinated Long-term Debt Proceeds from Issuance of Subordinated Long-term Debt Investment Banking, Advisory, Brokerage, and Underwriting Fees and Commissions Investment Banking, Advisory, Brokerage, and Underwriting Fees and Commissions Subordinated Borrowing, Interest Rate Subordinated Borrowing, Interest Rate Equity Units, Annual Distribution Rate Equity Units, Annual Distribution Rate Equity Units, Annual Distribution Rate Forward Contract Payment Rate Forward Contract Payment Rate Quarterly contract payments representing a proxy for dividend yield investors would receive if shares have been held from inception Per Unit Conversion Rate For Equity Security Units Debt Instrument, Convertible, Conversion Price Market Price required for Equity Unit Conversion Market Price required for Equity Unit Conversion Market Price required for Equity Unit Conversion Common Shares Issueable At Maturity Common Shares Issueable At Maturity Common Shares Issueable At Maturity Equity Units Share Price Equity Units Share Price Equity Units Share Price Share Price Share Price Debt Instrument, Collateral Amount Debt Instrument, Collateral Amount Derivative, Notional Amount Derivative, Notional Amount Repayments of First Mortgage Bond Repayments of First Mortgage Bond Repayments of Secured Debt Repayments of Secured Debt Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum Redemption Premium Redemption Premium Scenario Adjustment [Member] Scenario, Adjustment [Member] Derivative, Gain (Loss) on Derivative, Net Derivative, Gain (Loss) on Derivative, Net Mark-to-market derivative assets (noncurrent assets) Mark-to-market derivative liabilities (current liabilities) Mark-to-market derivative liabilities (noncurrent liabilities) Total mark-to-market derivative liabilities Current assets collateral offset Collateral Amount Offset Against Fair Value Of Derivative Current Asset The amount as of the balance sheet date of cash collateral that was offset against the fair value of derivative current assets. Noncurrent assets collateral offset Collateral Amount Offset Against Fair Value Of Derivatives Noncurrent Asset The amount as of the balance sheet date of cash collateral that was offset against the fair value of derivative noncurrent assets. Current liabilities collateral offset Collateral Amount Offset Against Fair Value Of Derivative Current Liability The amount as of the balance sheet date of cash collateral that was offset against the fair value of derivative current liabilities. Noncurrent liabilities collateral offset Collateral Amount Offset Against Fair Value Of Derivative Current Noncurrent Liability The amount as of the balance sheet date of cash collateral that was offset against the fair value of derivative noncurrent liabilities. Total cash collateral received net of cash collateral posted Collateral Received Net Of Collateral Posted Offset Against Fair Value Of Derivative Assets And Liabilities The amount as of the balance sheet date of cash collateral received net of cash collateral posted that was offset against mark-to-market assets and liabilities. Property, Plant and Equipment [Abstract] Impairment of Long-Lived Assets (Exelon and Generation) Impairment Of Long Lived Assets Held [Text Block] Asset Impairment Charges [Text Block] Asset Impairment Charges [Text Block] Debt and Credit Agreements (Exelon, Generation, ComEd, PECO and BGE) Debt Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Events (Exelon and Generation) Subsequent Events [Text Block] Income Taxes (Exelon, Generation, ComEd, PECO and BGE) Income Tax Disclosure [Text Block] Reconciliation of basic and diluted earnings per share Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table Text Block] Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Perryman Construction [Member] Perryman Construction [Member] Fourmile Construction [Member] FourmileConstructionMember [Member] Combine-cycle Turbine Units [Member] Combine-cycle Turbine Units [Member] Combine-cycle Turbine Units [Member] Accrual For Environmental Loss Contingencies Material Components [Axis] Accrual For Environmental Loss Contingencies Material Components [Axis] Accrual For Environmental Loss Contingencies Material Components [Domain] Accrual For Environmental Loss Contingencies Material Components [Domain] Accrual For Environmental Loss Contingencies Material Components [Domain] Beebe Construction [Member] Beebe Construction [Member] Other Commitments [Axis] Other Commitments [Axis] Other Commitments [Domain] Other Commitments [Domain] Fair Wind Project [Member] Fair Wind Project [Member] Fair Wind Project [Member] Sendero Wind Project [Member] Sendero Wind Project [Member] Sendero Wind Project [Member] AGE Biomass project [Member] AGE Biomass project [Member] AGE Biomass project [Member] Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] Accrued environmental liabilities Accrual for Environmental Loss Contingencies Business Acquisition, Direct Investment With State And Local Governments Due To Settlement Business Acquisition, Direct Investment With State And Local Governments Due To Settlement Direct investment to local and state governments for the settlement in a business acquisition. Business Acquisition, Construction Cost Business Acquisition, Construction Cost The portion of the acquisition commitment with the regulatory agencies related to expected construction costs for a new building. Minimum future operating lease payments due in one year Operating Leases, Future Minimum Payments Due, Next Twelve Months Minimum future operating lease payments due in three years Operating Leases, Future Minimum Payments, Due in Three Years Minimum future operating lease payments due in four years Operating Leases, Future Minimum Payments, Due in Four Years Minimum future operating lease payments due in five years Operating Leases, Future Minimum Payments, Due in Five Years Minimum future operating lease payments due beyond five years Operating Leases Future Minimum Payments Due Beyond Five Years For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due after the fifth year of the balance sheet date relating to leases defined as operating. Business Acquisition, Development Of New Generation Cost Business Acquisition, Development Of New Generation Cost The portion of the acquisition settlement related to the expected cost of developing new generation. Business Acquisition, Expected New Generation Mwh Business Acquisition, Expected New Generation Mwh The expected capacity of new generation development related to the acquisition settlement. Noncash Merger Related Costs Noncash Merger Related Costs Loss Contingency, Loss in Period Loss Contingency, Loss in Period Operating Leases, Future Minimum Payments, Due in Two Years Operating Leases, Future Minimum Payments, Due in Two Years Costs Incurred, Development Costs Costs Incurred, Development Costs Capital Leases Net Investment In Direct Financing Leases [Table] Capital Leases Net Investment In Direct Financing Leases [Table] Capital Leases Net Investment In Direct Financing Leases [Line Items] Capital Leases Net Investment In Direct Financing Leases [Line Items] Capital Leases, Net Investment in Direct Financing Leases [Abstract] Capital Leases, Net Investment in Direct Financing Leases [Abstract] Carrying Amount Of Long Lived Assets To Be Written Down Impaired Assets to be Disposed of by Method Other than Sale, Carrying Value of Asset Impaired Assets Fair Value Impaired Assets Fair Value Impaired Assets Fair Value Tangible Asset Impairment Charges Tangible Asset Impairment Charges Utilities Operating Expense, Impairments Utilities Operating Expense, Impairments Interest Costs Incurred Interest Costs Incurred Estimated residual value of leased assets Capital Leases, Net Investment in Direct Financing Leases, Unguaranteed Residual Values of Leased Property Capital Lease Net Investment In Direct Financing Leases Prepayments Received Capital Lease Net Investment In Direct Financing Leases Prepayments Received Capital Lease Net Investment in Direct Financing Leases Prepayments Received Proceeds From Lease Termination Proceeds From Lease Termination Cash Proceeds from Direct Finance Lease Contract Termination Capital Leases Net Investment In Direct Financing Leases Writeoff Capital Leases Net Investment In Direct Financing Leases Writeoff Capital Leases Net Investment In Direct Financing Leases Writeoff Impairment of Long-Lived Assets to be Disposed of Impairment of Long-Lived Assets to be Disposed of Statement of Cash Flows [Abstract] Net Cash Provided by (Used in) Operating Activities [Abstract] Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Adjustments to reconcile net income to net cash flows provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation, amortization, depletion and accretion, including nuclear fuel and energy contract amortization Depreciation, Amortization and Accretion, Net Impairment of long-lived assets Impairment of Long-Lived Assets Held-for-use Gain on consolidation and acquisition of businesses Equity Method Investment, Realized Gain (Loss) on Disposal Gain on sales of assets Deferred income taxes and amortization of investment tax credits Deferred Income Taxes and Tax Credits Net fair value changes related to derivatives Net realized and unrealized (gains) losses on nuclear decommissioning trust fund investments Gain (Loss) on Investments Other non-cash operating activities Other Noncash Income (Expense) Changes in assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Receivables Receivables from and payables to affiliates, net Change Receivables Payables From Affiliates The net change in related receivables and payables from entities that are affiliated with the reporting entity by means of direct or indirect ownership. A positive value indicates a decrease in the net receivable or an increase in the net payable, while a negative value indicates an increase in the net receivable or a decrease in the net payable. Inventories Increase (Decrease) in Inventories Accounts payable, accrued expenses and other current liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Option premiums received, net Changes In Option Premiums Collected Received The net change during the reporting period in option premiums collected and paid. Options reflect the right or obligation to buy or sell an energy-related commodity and are classified in current and long-term mark-to-market derivative assets and liabilities. Counterparty collateral received (posted), net Increase Decrease In Counterparty Collateral Net The net change during the reporting period in money or securities placed with a broker or counterparty as security for a trading or derivative position and the amount of customer money held in customer accounts, including security deposits, collateral for a current or future transactions, initial payment of the cost of acquisition or for the right to enter into a contract or agreement. Income taxes Increase (Decrease) in Income Taxes Payable Pension and non-pension postretirement benefit contributions Pension and Other Postretirement Benefit Contributions Other assets and liabilities Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash flows provided by operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Capital expenditures Payments to Acquire Property, Plant, and Equipment Proceeds from nuclear decommissioning trust fund sales Proceeds from Sale and Maturity of Other Investments Investment in nuclear decommissioning trust funds Payments to Acquire Other Investments Proceeds from nuclear decommissioning trust fund sales Proceeds from Collection of (Payments to Fund) Long-term Loans to Related Parties Acquisition of businesses Payments to Acquire Businesses, Gross Proceeds from sale of long-lived assets Proceeds from Sale of Property Held-for-sale Proceeds from termination of direct financing lease investment Proceeds from sales of investments Proceeds from Sale, Maturity and Collection of Investments Purchases of investments Payments to Acquire Marketable Securities Change in restricted cash Increase (Decrease) in Restricted Cash Cash and restricted cash acquired from consolidations and acquisitions Cash Acquired from Acquisition Other investing activities Payments for (Proceeds from) Other Investing Activities Changes in Exelon intercompany money pool Change in Exelon intercompany money pool borrowings Documentation to be provided Funding of Exelon intercompany money pool Funding of Exelon intercompany money pool Funding of Exelon intercompany money pool Net cash flows used in investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net Cash Provided by (Used in) Financing Activities [Abstract] Net Cash Provided by (Used in) Financing Activities [Abstract] Payment of accounts receivable agreement Repayments of Accounts Receivable Securitization Changes in short-term borrowings Proceeds from (Repayments of) Short-term Debt, Maturing in Three Months or Less Issuance of long-term debt Proceeds from Issuance of Long-term Debt Retirement of long-term debt Repayments of Related Party Debt Repayments of Related Party Debt Redemption of preferred securities Proceeds from (Repurchase of) Redeemable Preferred Stock Distributions to noncontrolling interest of consolidated VIE Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Payments to Noncontrolling Interests Payments to Noncontrolling Interests Dividends paid on common stock Payments of Ordinary Dividends, Common Stock Proceeds from employee stock plans Proceeds from Stock Plans Other financing activities Proceeds from (Payments for) Other Financing Activities Changes in short-term borrowings Repayments of Notes Payable Distribution to member Payments of Distributions to Affiliates Contributions from parent Proceeds from Contributions from Parent Payments of Ordinary Dividends, Preferred Stock and Preference Stock Payments of Ordinary Dividends, Preferred Stock and Preference Stock Contribution from member Proceeds from Contributions from Affiliates Proceeds from Issuance of Common Stock Proceeds from Issuance of Common Stock Net cash flows provided by financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations Increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Proceeds from (Payments for) Deposits Applied to Debt Retirements Proceeds from (Payments for) Deposits Applied to Debt Retirements Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Table] Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Table] Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items] Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items] Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items] Effective Income Tax Rate Reconciliation, Percent [Abstract] Effective Income Tax Rate Reconciliation, Percent [Abstract] U.S. Federal statutory rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Increase (Decrease) due to Adjustments To Reconcile Federal Statutory Income Tax Rate To Effective Income Tax Rate Continuing Operations [Abstract] Adjustments to reconcile the domestic federal statutory tax rate to a company's effective income tax rate abstract. State income taxes, net of Federal income tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Qualified nuclear decommissioning trust fund income Effective Income Tax Rate Reconciliation Qualified Nuclear Decommissioning Trust Fund Income Losses The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by income or losses generated by the qualified nuclear decommissioning trust funds that are taxed at a higher rate. Domestic production activities deduction Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Percent Health care reform legislation Effective Income Tax Rate Reconciliation Elimination Of Deductions Medicare Prescription Drug Benefit The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to the elimination of the deduction previously received for Medicare prescription drug benefits in accordance with the Patient Protection and Affordable Care Act, as modified by the Health Care and Education Reconciliation Act. Amortization of investment tax credit, net deferred taxes Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Percent Plant basis differences Effective Income Tax Rate Reconciliation Plant Basis Differences The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by the difference in depreciation and amortization methods allowed under generally accepted accounting principles and enacted tax laws. Production tax credits and other credits Effective Income Tax Rate Reconciliation, Deduction, Other, Percent Statute of limitations expiration Effective income tax reconciliation statue expiration Effective income tax reconciliation statue expiration Noncontrolling interest Effective Income Tax Rate Reconciliation, Noncontrolling Interest Income (Loss), Percent Other Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Effective Income Tax Rate Reconciliation, Percent Effective Income Tax Rate Reconciliation, Percent Schedule of Short-term Debt [Table] Schedule of Short-term Debt [Table] Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Commercial Paper [Member] Commercial Paper [Member] Short-term Debt [Line Items] Short-term Debt [Line Items] Commercial paper borrowings Commercial Paper Equity Method Investments and Joint Ventures [Abstract] Investment in Constellation Energy Nuclear Group, LLC (Exelon and Generation) Equity Method Investments and Joint Ventures Disclosure [Text Block] Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member] Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member] Assets [Abstract] Assets [Abstract] Assets, Current [Abstract] Assets, Current [Abstract] Cash and cash equivalents Restricted cash and cash equivalents Restricted Cash and Cash Equivalents, Current Accounts receivable, net Accounts Receivable, Net, Current [Abstract] Customer Accounts Receivable, Net, Current Other Other Receivables Mark-to-market derivative assets Unamortized energy contract assets Energy Marketing Contracts Assets, Current Income taxes receivable Income Taxes Receivable, Current Receivables from affiliates Due from Affiliate, Current Receivable from Exelon intercompany money pool Due from Related Parties, Current Inventories, net Inventory, Net [Abstract] Fossil fuel and emission allowances Energy Related Inventory, Other Fossil Fuel Materials and supplies Inventory, Raw Materials and Supplies, Gross Deferred income taxes Deferred Tax Assets, Net of Valuation Allowance, Current Regulatory assets Regulatory Assets, Current Disposal Group, Including Discontinued Operation, Assets, Current Other Other Assets, Current Prepaid utility taxes Prepaid Taxes Inventories, net Inventory, Net Total current assets Assets, Current Property, plant and equipment, net Property, Plant and Equipment, Net Deferred debits and other assets Other Assets, Noncurrent [Abstract] Nuclear decommissioning trust funds Decommissioning Fund Investments Investments Long-term Investments Investments in affiliates Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Investment in CENG Equity Method Investments Goodwill Goodwill Unamortized energy contracts assets Energy Marketing Contracts Assets, Noncurrent Deferred Tax Assets, Net, Noncurrent Deferred Tax Assets, Net, Noncurrent Pledged assets for Zion Station decommissioning Assets Held-in-trust, Noncurrent Other Other Assets, Noncurrent Receivable from affiliate Due from Affiliate, Noncurrent Prepaid pension asset Prepaid Pension Costs Total deferred debits and other assets Total Deferred Debits And Other Assets Total deferred debits and other assets. Total assets Assets Liabilities and Equity [Abstract] Liabilities and Equity [Abstract] Liabilities, Current [Abstract] Liabilities, Current [Abstract] Short-term borrowings Short-term Debt Long-term debt due within one year Long-term Debt and Capital Lease Obligations, Current Accounts payable Accounts Payable, Current Accrued expenses Deferred income taxes Deferred Tax Liabilities, Net, Current Regulatory liabilities Regulatory Liability, Current Mark-to-market derivative liabilities (current liabilities) Unamortized energy contract liabilities Energy Marketing Contract Liabilities, Current Payables to affiliates Due to Affiliate Related Party Transaction, Due from (to) Related Party Related Party Transaction, Due from (to) Related Party Customer deposits Customer Deposits, Current Due to Affiliate, Current Due to Affiliate, Current Total current liabilities Liabilities, Current Long-term debt Long-term Debt, Excluding Current Maturities Long-term debt to financing trusts Due to Related Parties, Noncurrent Long-term debt to affiliate Long Term Debt To Affiliate Long term debt to affiliates Deferred credits and other liabilities Other Liabilities, Noncurrent [Abstract] Deferred income taxes and unamortized investment tax credits Deferred Income Taxes And Unamortized Investment Tax Credits Represents the noncurrent portion of deferred tax liabilities, 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. Additionally, this element includes the future effects on income taxes attributable to investment tax credits. Asset retirement obligations Asset Retirement Obligations, Noncurrent Pension obligations Defined Benefit Pension Plan, Liabilities, Noncurrent Non-pension postretirement benefit obligations Other Postretirement Defined Benefit Plan, Liabilities, Noncurrent Spent nuclear fuel obligation Spent Nuclear Fuel Obligation, Noncurrent Regulatory liabilities Regulatory Liability, Noncurrent Mark-to-market derivative liabilities (noncurrent liabilities) Unamortized energy contract liabilities Energy Marketing Contract Liabilities, Noncurrent Payable for Zion Station decommissioning Decommissioning Liability, Noncurrent Other Other Liabilities, Noncurrent Payables to affiliates Due to Affiliate, Noncurrent Total deferred credits and other liabilities Total Deferred Credits And Other Liabilities Total deferred credits and other liabilities. Total liabilities Liabilities Commitments and contingencies Commitments and Contingencies Common stock Common Stock, Value, Issued Treasury stock, at cost (35 shares at both September 30, 2015 and December 31, 2014) Retained earnings Retained Earnings (Accumulated Deficit) Other paid-in capital Additional Paid in Capital Accumulated other comprehensive loss, net Total shareholders’ equity Stockholders' Equity Attributable to Parent BGE preference stock not subject to mandatory redemption Preferred Stock, Value, Issued Noncontrolling interest Stockholders' Equity Attributable to Noncontrolling Interest Total equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and shareholders’ equity Liabilities and Equity Total liabilities and shareholders' equity Liabilities And Stockholders Equity Including Portion Attributable To Noncontrolling Interest Liabilities and total of Stockholders' Equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity including portions attributable to both the parent and noncontrolling interests (previously referred to as minority interest), if any. The entity including portions attributable to the parent and noncontrolling interests is sometimes referred to as the economic entity. This excludes temporary equity and is sometimes called permanent equity. Equity Members Equity Including Portion Attributable To Noncontrolling Interest [Abstract] Members' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Member’s equity Members' Equity [Abstract] Membership interest Membership Interests An ownership interest in a limited liability company Undistributed earnings Members Equity Retained Earnings Cumulative undistributed earnings of an entity; shall be considered to be part of member's equity. Total member's equity Members' Equity Total equity Members Equity Including Portion Attributable To Noncontrolling Interest Total of member's equity (deficit) items, including portions attributable to both the parent and noncontrolling interests (previously referred to as minority interest), if any. The entity including portions attributable to the parent and noncontrolling interests is sometimes referred to as the economic entity. This excludes temporary equity and is sometimes called permanent equity. Total liabilities and equity Liabilities And Members Equity Total liabilities and member's equity. Derivative Instruments (Exelon, Generation, ComEd, PECO and BGE) Derivative Instruments and Hedging Activities Disclosure [Text Block] Activity of severance obligations for the corporate restructuring (excluding obligations recorded in equity) Schedule of Restructuring Reserve by Type of Cost [Table Text Block] Restructuring and Related Costs Restructuring and Related Costs [Table Text Block] Restructuring Charges [Abstract] Severance (Exelon, Generation, ComEd, PECO and BGE) Restructuring and Related Activities Disclosure [Text Block] Segment Information (Exelon, Generation, ComEd, PECO and BGE) Segment Reporting Disclosure [Text Block] Fair Value Inputs, Assets, Quantitative Information [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] All Regions excluding New England [Member] All Regions excluding New England [Member] All Regions excluding New England [Member] Valuation Technique [Axis] Valuation Technique [Axis] Valuation Technique [Domain] Valuation Technique [Domain] Discounted Cash Flow [Member] Income Approach Valuation Technique [Member] Option Model Valuation Technique [Member] Option Model Valuation Technique [Member] Option model approach valuation technique used to measure fair value. Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Derivative Asset, Fair Value, Amount Not Offset Against Collateral Derivative Asset, Fair Value, Amount Not Offset Against Collateral Derivative Liability, Fair Value, Amount Not Offset Against Collateral Derivative Liability, Fair Value, Amount Not Offset Against Collateral Fair Value Inputs [Abstract] Fair Value Inputs [Abstract] Forward power price assets Fair Value Inputs Forward Power Price Assets This element represents the forward power market price used to calculate the change in fair value of the derivative instrument. Forward gas price assets Fair Value Inputs Forward Gas Price Assets This element represents the forward power market price used to calculate the change in fair value of the derivative instrument. Volatility percentage Fair Value Assumptions, Expected Volatility Rate Marketability Reserve Fair Value Inputs, Discount for Lack of Marketability Forward heat rate Fair Value Inputs Forward Heat Rate This element represents the factor that is multiplied with the forward price of natural gas to calculate a forward power curve. Natural gas has greater liquidity tenor than power and is commonly used to calculate this curve. Renewable factor Fair Value Inputs Renewable Factor This element represents a factor to adjust an around the clock forward power price and quantity to be in line with an applicable renewable facility. Solar units generally produce more power in the summer days and wind units generally produce more power in the spring and fall evenings. Derivatives Fair Value Footnotes [Abstract] Derivatives Fair Value Footnotes [Abstract] Cash collateral excluded Fair Value Inputs Cash Collateral Excluded This element represents the Level 3 cash collateral value excluded from the significant inputs to the forward curve used to value swap contracts Public Utilities, Inventory, Fuel [Member] Public Utilities, Inventory, Fuel [Member] Implications of Potential Early Plant Retirements [Abstract] Implications of Potential Early Plant Retirements [Abstract] Implications Of Potential Early Retirement Disclosure [Text Block] Implications Of Potential Early Retirement Disclosure [Text Block] implications of potential early retirement disclosure [Text Block] Severance Costs Payments for Restructuring Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Public Utility [Axis] Public Utility [Axis] Utility Plant [Domain] Utility Plant [Domain] Nuclear Plant [Member] Nuclear Plant [Member] Quad Cities [Member] Quad Cities [Member] Quad Cities [Domain] Clinton [Member] Clinton [Member] Clinton [Member] Ginna [Member] Ginna [Member] Ginna [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Inventory, Raw Materials and Supplies, Gross Nuclear Fuel, Net of Amortization Nuclear Fuel, Net of Amortization Property, Plant and Equipment, Net Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress Asset Retirement Obligation Asset Retirement Obligation Nuclear Decommissioning Additional Narrative Information [Table] Nuclear Decommissioning Additional Narrative Information [Table] Nuclear Decommissioning Additional Narrative Information [Table] Nuclear Decommissioning Additional Narrative Information [Line Items] Nuclear Decommissioning Additional Narrative Information [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Payable to Zion Solutions Payable To Thirdparty To Decommission Nuclear Plant Funded By Pledged Assets Total gross amount of liability as of the balance sheet date associated with the asset sale agreement and transfer of asset retirement obligation to ZionSolutions. Current portion of payable to Zion Solutions Current Portion Of Payable To Thirdparty To Decommission Nuclear Plant, Funded By Pledged Assets Current amount of liability as of the balance sheet date associated with the asset sale agreement and transfer of asset retirement obligation to ZionSolutions, included in Other Current Liabilities on the Balance Sheet. Withdrawals by Zion Solutions to pay decommissioning costs Withdrawal From Nuclear Decommissioning Funds The cash outflow from nuclear decommissioning funds during the period. Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Schedule of total equity in earnings of investment in CENG Schedule Of Income Loss From Equity Method Investments [Table Text Block] This element may be used to capture the table showing the different components of income or loss from equity method investments. Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Fair Value Hedging [Member] Fair Value Hedging [Member] Gain (Loss) on Fair Value Hedges Recognized in Earnings Gain (Loss) on Fair Value Hedges Recognized in Earnings Derivative, Net Hedge Ineffectiveness Gain (Loss) Derivative, Net Hedge Ineffectiveness Gain (Loss) Less: unearned income Capital Leases, Net Investment in Direct Financing Leases, Deferred Income Net investment in long-term leases Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Schedule Of Other Comprehensive Income Loss Tax Schedule Of Other Comprehensive Income Loss Tax [Table Text Block] Schedule Of Other Comprehensive Income Loss Tax Statement of Stockholders' Equity [Abstract] Undistributed Earnings [Member] Undistributed Earnings [Member] Undistributed Earnings. Common Stock [Member] Common Stock [Member] Treasury Stock [Member] Treasury Stock [Member] Membership Interest [Member] Membership Interest [Member] An ownership interest in a limited liability company. Retained Earnings [Member] Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) [Member] AOCI Attributable to Parent [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Preference Stock Not Subject To Mandatory Redemption [Member] Preference Stock Not Subject To Mandatory Redemption [Member] Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity. Other Additional Capital [Member] Other Additional Capital [Member] Retained Earnings, Unappropriated [Member] Retained Earnings, Unappropriated [Member] Retained Earnings, Appropriated [Member] Retained Earnings, Appropriated [Member] Preferred Stock [Member] Preferred Stock [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance (in shares) Shares, Issued Beginning Balance Noncontrolling Interest, Increase from Sale of Parent Equity Interest Noncontrolling Interest, Increase from Sale of Parent Equity Interest Long-term incentive plan activity (in shares) Stock Issued During Period Shares Long Term Incentive Plan Activity Number of shares of stock issued under long-term incentive plan activity. Long-term incentive plan activity Stock Issued During Period, Value, Long Term Incentive Plan Activity Change in the value of common stock equity related to long-term incentive plan activity. Employee stock purchase plan issuances (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Employee stock purchase plan issuances Stock Issued During Period, Value, Employee Stock Purchase Plan Appropriation of retained earnings for future dividends Appropriation of Retained Earnings for Future Dividends Appropriation of retained earnings for future dividends. Tax benefit on stock compensation Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Common stock dividends Dividends, Common Stock, Cash Contribution from parent Members Equity Including Portion Attributable To Noncontrolling Interest Acquisitions Total of member's equity (deficit) items, including portions attributable to both the parent and noncontrolling interests attributed to an acquisition. Distribution to members Distribution to members Distribution to members. Allocation of tax benefit from members Allocation Of Tax Benefit From Members Allocation of tax benefit from members Preferred stock redemption premium Allocation of tax benefit from parent Allocation Of Tax Benefit From Parent Allocation Of Tax Benefit From Parent Consolidated VIE dividend to non-controlling interest Reversal of CENG equity method AOCI, net of income taxes of $77 OtherComprehensiveIncomeLossNetoOfTaxPeriodDecrease OtherComprehensiveIncomeLossNetoOfTaxPeriodDecrease Minority Interest Increase From Acquisition Minority Interest Increase From Acquisition Increase in noncontrolling interest balance from acquisition of additional noncontrolling interest holders. Preferred security dividends Dividends, Preferred Stock, Cash Long-term Debt, Excluding Current Maturities Fair Value of Financing Contract Payments Fair Value of Financing Contract Payments Noncontrolling interest acquired Noncontrolling Interest, Increase from Business Combination Increase (Decrease) in Pension and Postretirement Obligations Increase (Decrease) in Pension and Postretirement Obligations Stock Issued During Period, Shares, New Issues Stock Issued During Period, Shares, New Issues Stock Issued During Period, Value, New Issues Stock Issued During Period, Value, New Issues Other comprehensive loss, net of income taxes of $53 Other Comprehensive Income (Loss) excluding Equity Method AOCI, Net of Tax Other Comprehensive Income (Loss) excluding Equity Method AOCI, Net of Tax Other comprehensive income (loss), net of tax Ending Balance Ending Balance (in shares) Document and Entity Information [Abstract] Document and Entity Information. Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Common Stock Shares Outstanding Entity Common Stock, Shares Outstanding Fair Value Assets And Liabilities Measured On Recurring Basis Gain Loss Included In Earnings [Table] Schedule that discloses total realized and unrealized gains/losses included in income for assets and liabilities with unobservable inputs measured on a recurring basis. Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation By Asset Liability Type [Axis] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation By Asset Liability Type [Axis] This element represents a number of concepts which are required or determined to be provided for purposes of reconciling beginning and ending balances of fair value measurements of assets and liabilities using significant unobservable inputs (Level 3). Such reconciliation, separately presenting changes during the period, at a minimum, may include: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (net); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs). Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Inputs Reconciliation Asset Types [Domain] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Inputs Reconciliation Asset Types [Domain] This element provides general categories of investment (assets and liabilities) for which the fair value measurement of assets and liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (net); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs). Purchased Fuel and Electric [Member] Purchased Fuel and Electric [Member] This element represents the gains (losses) included in earnings that recognized in purchased fuel and electric expense. Other, net [Member] Other, net [Member] This element represents the gains (losses) included in earnings that recognized in Other, net. Fair Value Assets And Liabilities Measured On Recurring Basis Gain Loss Included In Earnings [Line Items] Fair Value Assets And Liabilities Measured On Recurring Basis Gain Loss Included In Earnings [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Employee Severance [Member] Employee Severance [Member] Other Severance Charges [Member] Other Severance Charges [Member] Other severance charges including but not limited to life insurance, employer payroll taxes, educational assistance and outplacement services Restructuring Reserve [Roll Forward] Restructuring Reserve [Roll Forward] Beginning Balance Restructuring Reserve Severance Charges Expense Severance Charges Expense Severance charge expense with O&M Payments for Restructuring Ending Balance Supplemental Financial Information (Exelon, Generation, ComEd, PECO and BGE) Supplemental Financial Information Disclosure [Text Block] Element designated to encapsulate the entire footnote disclosure that provides information on the supplemental income statement, cash flow and balance sheet activities. Additional Financial Information Disclosure [Text Block] Additional Financial Information Disclosure [Text Block] Asset Retirement Obligation Roll Forward Analysis [Table] Asset Retirement Obligation Roll Forward Analysis [Table] A table for the reconciliation of the nuclear decommissioning asset retirement obligation from the beginning of a period to the end of a period. Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Nuclear Decommissioning Asset Retirement Obligation [Member] Nuclear Decommissioning Asset Retirement Obligation [Member] Asset Retirement Obligation Roll Forward Analysis [Line Items] Asset Retirement Obligation Roll Forward Analysis [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. NuclearDecommissioningTrustFundFixedIncomeSecuritiesPercent NuclearDecommissioningTrustFundFixedIncomeSecuritiesPercent NuclearDecommissioningTrustFundFixedIncomeSecuritiesPercent Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Nuclear Decommissioning ARO, Beginning Balance Accretion expense Asset Retirement Obligation Accretion Expense Impact Amount of nuclear accretion expense recognized in the income statement during the period that is associated with nuclear asset retirement obligations. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability. Such accretion expense representing changes in the liability for a nuclear asset retirement obligation due to passage of time is the result of applying an interest method of allocation to the amount of the liability at the beginning of the period. The interest rate used to measure that change shall be the credit-adjusted risk-free rate that existed when the liability, or portion thereof, was initially measured. That amount shall be recognized as an increase in the carrying amount of the liability and as an expense classified as an operating item in the statement of income. Accretion expense shall not be considered to be interest cost for purposes of capitalization of interest. Costs incurred to decommission retired plants Asset Retirement Obligation, Liabilities Settled Nuclear Decommissioning ARO, Ending Balance Asset Retirement Obligation, Revision of Estimate Asset Retirement Obligation, Revision of Estimate Asset Retirement Obligation, Accretion Expense Asset Retirement Obligation, Accretion Expense Current portion of ARO Asset Retirement Obligation, Current Credit Rating Source [Axis] Credit Rating Source [Axis] Credit Rating Source [Domain] Credit Rating Source [Domain] External Credit Rating, Investment Grade [Member] External Credit Rating, Investment Grade [Member] External Credit Rating, Non Investment Grade [Member] External Credit Rating, Non Investment Grade [Member] Risk Level, High [Member] Risk Level, High [Member] Risk Level, Low [Member] Risk Level, Low [Member] Credit Derivatives Contract Type [Axis] Credit Derivatives Contract Type [Axis] Credit Derivatives Contract Type [Domain] Credit Derivatives Contract Type [Domain] Financial institution [Member] Financial institution [Member] Financial institution [Member] Energy Cooperatives And Municipalities [Member] Energy Cooperatives And Municipalities [Member] Energy Cooperatives And Municipalities [Member] Investor Owned Utilities Marketers And Power Producers Credit Risk Exposure [Member] Investor Owned Utilities Marketers And Power Producers Credit Risk Exposure [Member] Investor Owned Utilities Marketers And Power Producers Credit Risk Exposure [Member] Other Credit Risk Exposure [Member] Other Credit Risk Exposure [Member] Other Credit Risk Exposure [Member] Total Credit Risk Exposure Total Credit Risk Exposure Total credit risk exposure. Investor-owned utilities, marketers and power producers Investor Owned Utilities Marketers And Power Producers Credit Risk Exposure Credit exposure for all derivative instruments, normal purchase-normal sale, and related payables and receivables (net of collateral and instruments that are subject to master netting agreements) from group of counterparties comprised of investor-owned utilities, marketers and power producers. Credit Derivative, Maximum Exposure, Undiscounted Credit Derivative, Maximum Exposure, Undiscounted Credit derivative net exposure Credit derivative net exposure Credit derivative net exposure Credit Derivative, Collateral Held Directly or by Third Parties Credit Derivative, Collateral Held Directly or by Third Parties Number of Credit Risk Derivatives Held Number of Credit Risk Derivatives Held Derivative Credit Risk Valuation Adjustment, Derivative Assets Derivative Credit Risk Valuation Adjustment, Derivative Assets PECO Energy Co Affiliate [Member] PECO Energy Co Affiliate [Member] Peco Energy Co Related Party Affiliate Baltimore Gas And Electric Company Affiliate [Member] Baltimore Gas And Electric Company Affiliate [Member] Baltimore Gas and Electric Related Party Affiliate Related Project [Axis] Related Project [Axis] Related Project [Domain] Related Project [Domain] Antelope Valle [Member] Antelope Valle [Member] Debt issued to fund the Antelope Valley Project Other Solar Projects [Member] Other Solar Projects [Member] PHI Merger [Member] PHI Merger [Member] PHI Merger [Member] Interest Rate Contract [Member] Interest Rate Contract [Member] Foreign Exchange Contract [Member] Foreign Exchange Contract [Member] Energy Supply Procurement [Member] Energy Supply Procurement [Member] Energy Supply Procurement Member ReNewAble Energy Contract [Member] ReNewAble Energy Contract [Member] ReNewAble Energy Contract [Member] Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax Hypothetical Increase In Interest Rates Hypothetical Increase In Interest Rates Represents a hypothetical increase in interest rate percentages to be used in an interest rate sensitivity analysis. Expected Generation Hedged In Next Twelve Months Expected Generation Hedged In Next Twelve Months The percent for the expected/target percentage of future generation being hedged at an electric generation company in the next twelve months. The percentage of expected generation hedged is calculated as the amount of equivalent sales divided by the expected generation. Expected generation represents the amount of energy estimated to be generated or purchased through owned or contracted capacity. Equivalent sales represent all hedging products, which include cash-flow hedges, other derivatives and certain non-derivative contracts including sales to affiliates to serve their retail load. Expected Generation Hedged In Year Two Expected Generation Hedged In Year Two The percent for the expected/target percentage of future generation being hedged at an electric generation company in year two. The percentage of expected generation hedged is calculated as the amount of equivalent sales divided by the expected generation. Expected generation represents the amount of energy estimated to be generated or purchased through owned or contracted capacity. Equivalent sales represent all hedging products, which include cash-flow hedges, other derivatives and certain non-derivative contracts including sales to affiliates to serve their retail load. Expected generation hedged in year three Expected Generation Hedged In Year Three The percent for the expected/target percentage of future generation being hedged at an electric generation company in year three. The percentage of expected generation hedged is calculated as the amount of equivalent sales divided by the expected generation. Expected generation represents the amount of energy estimated to be generated or purchased through owned or contracted capacity. Equivalent sales represent all hedging products, which include cash-flow hedges, other derivatives and certain non-derivative contracts including sales to affiliates to serve their retail load. Estimated percentage of natural gas purchases hedged Estimated Percent Of Gas Purchases Being Hedged The expected/target percentage of future gas purchases being hedged at a gas distribution company. The percentage is calculated as the amount of hedging products divided by the planned natural gas purchases in support of projected firm sales. Proprietary trading activities volume Proprietary Trading Volumes The volume in GWh of energy-related derivative contracts entered into purely to profit from market prices changes as opposed to hedging an exposure. Notional Amount of Pre-issuance Interest Rate Cash Flow Hedge Derivatives Notional Amount Of Preissuance Interest Rate Cash Flow Hedge Derivatives Aggregate notional amount of pre-issuance interest rate derivatives designated as hedging instruments in cash flow hedges. Notional amount refers to the monetary amount specified in the interest rate derivative contract. Hypothetical increase in interest rates associated with variable-rate debt Hypothetical Effect of Increase in Interest Rates Represents a hypothetical increase in interest rate percentages to be used in an interest rate sensitivity analysis. Increase In Notional Amount Of Derivative Instruments1 Increase In Notional Amount Of Derivative Instruments1 Increase in derivative notional amount due to additional fixed to float interest swap opened in the first quarter of 2014 Ineffective portion recognized in income Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss) Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss) Notional amounts on forward starting interest rate swaps Notional Amounts Forward Starting Interest Rate Swaps Notional amounts on forward starting interest rate swaps Cash collateral received not offset against net derivative positions Cash Collateral Received Not Offset Against Net Derivative Position The amount as of the balance sheet date of cash collateral received that was not offset against the fair value of derivative positions. Credit exposure under natural gas supply and management agreements Cash collateral posted Derivative, Collateral, Right to Reclaim Cash Letters of credit collateral posted Derivative, Collateral, Right to Reclaim Securities Net receivable from electric utility Due From Affiliate Current Electric Utility Amount of receivables due from a electric entity that is affiliated with the reporting entity by means of direct or indirect ownership, due within 1 year (or 1 business cycle). Net receivable from affiliated electric and gas utility Due From Affiliate Current Electric Gas Utility Amount of receivables due from a electric and gas entity that is affiliated with the reporting entity by means of direct or indirect ownership, due within 1 year (or 1 business cycle). Expected reclassification from accumulated other comprehensive income to results of operations Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months Total Cash collateral held Derivative, Collateral, Obligation to Return Cash Letters of credit collateral posted Derivative, Collateral, Obligation to Return Securities Incremental collateral for loss of investment grade credit rating Incremental Collateral For Loss Of Investment Grade Credit Rating Incremental collateral amount required to be provided related to its financial instruments, including derivatives, non-derivatives, normal purchase normal sales contracts and applicable payables and receivables, if the credit rating is downgraded below investment grade. Interest Rate Fair Value Hedge Asset at Fair Value Interest Rate Fair Value Hedge Asset at Fair Value Derivative Asset, Fair Value of Collateral Derivative Asset, Fair Value of Collateral Counter Party With Exposure Counterparty with Exposure Counterparty with Exposure New Accounting Pronouncements and Changes in Accounting Principles [Abstract] New Accounting Pronouncements (Exelon, Generation, ComEd, PECO and BGE) New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Significant Accounting Policies [Text Block] Significant Accounting Policies [Text Block] Schedule of Regulatory Liabilities [Table] Schedule of Regulatory Liabilities [Table] Under-Recovered Electric Revenue Decoupling [Member] Under-Recovered Electric Revenue Decoupling [Member] Under-Recovered Electric Revenue Decoupling [Member] Under Recovered Decoupling Revenue [Member] Under Recovered Decoupling Revenue [Member] Represents the under-recovered (regulatory asset) distribution costs recoverable from customers. An under recovery means that the actual costs of electricity or natural gas realized by the regulated utility were more than the rates charged to customers during the period and are recoverable from customers. Over Recovered Decoupling Gas Revenue [Member] Over Recovered Decoupling Gas Revenue [Member] Represents the over-recovered (regulatory liability) gas distribution costs recoverable from customers. An over recovery means that the actual costs of electricity or natural gas realized by the regulated utility were less than the rates charged to customers during the period and are refundable to customers. Over Recovered Decoupling Electric Revenue [Member] Over Recovered Decoupling Electric Revenue [Member] Represents the over-recovered (regulatory liability) gas distribution costs recoverable from customers. An over recovery means that the actual costs of electricity or natural gas realized by the regulated utility were less than the rates charged to customers during the period and are refundable to customers. Other Postretirement Benefits [Member] Other Postretirement Benefits [Member] Discloses the amount of regulatory asset arising from the net periodic other postretirement benefit costs, according to US GAAP recovered through rate-making proceedings, according to the actions of the regulator. Nuclear Decommissioning [Member] Asset Retirement Obligation Costs [Member] Removal Costs [Member] Removal Costs [Member] Energy Efficiency Demand Response Programs [Member] Energy Efficiency Demand Response Programs [Member] Represents the over or under-recovered costs related to energy efficiency and demand response programs. Dlc Program Cost [Member] Dlc Program Cost [Member] Energy Efficiency Phase [Member] Energy Efficiency Phase [Member] Electric Transmission And Distribution Tax Repairs [Member] Electric Transmission And Distribution Tax Repairs [Member] Represents the expected total refund to customers for the tax cash benefit from the application of the safe harbor method of tax accounting to costs incurred prior to 2010. Gas Distribution Tax Repairs [Member] Gas Distribution Tax Repairs [Member] Represents the expected total refund to customers for the tax cash benefit from the application of the safe harbor method of tax accounting to costs incurred prior to 2011. Over-Recovered Universal Service Fund Costs [Member] Over-Recovered Universal Service Fund Costs [Member] A regulatory liability that represents the over-recovery of discounts issued to electric and gas customers enrolled in assistance programs. Revenue Subject to Refund [Member] Revenue Subject to Refund [Member] Over Recovered Decoupling Revenue [Member] Over Recovered Decoupling Revenue [Member] Regulatory Liabilities Other [Member] Regulatory Liabilities Other [Member] Carrying amount as of the balance sheet date of regulatory liabilities which are not elsewhere specified in the taxonomy. Over-Recovered Natural Gas Costs [Member] Over-Recovered Natural Gas Costs [Member] Over-Recovered Natural Gas Costs [Member] Merger Integration Costs [Member] Merger Integration Costs [Member] Environmental Restoration Costs [Member] Environmental Restoration Costs [Member] Over Recovered Electric Energy And Transmission Costs [Member] Over Recovered Electric Energy And Transmission Costs [Member] Represents the over-recovered (regulatory liability) electric supply related costs refundable to customers. An over recovery means that the actual costs of electic energy realized by the regulated utility were less than the rates charged to customers during the period and are refundable to customers. Regulatory Liabilities [Line Items] Regulatory Liabilities [Line Items] Current Noncurrent Over Recovered electric Supply Costs Over Recovered electric Supply Costs Over Recovered electric Supply Costs Renewable Energy Requirement Revenue Renewable Energy Requirement Revenue Renewable Energy Requirement Revenue Over recovered Natural Gas Supply Cost Over recovered Natural Gas Supply Cost Over recovered Natural Gas Supply Cost Default Service Provider Program Costs Default Service Provider Program Costs Default Service Provider Program Costs Over Recovered Electric Transmission Costs Over Recovered Electric Transmission Costs Over Recovered Electric Transmission Costs Over Recovered Electric Revenue Decoupling Over Recovered Electric Revenue Decoupling Over Recovered Electric Revenue Decoupling Over Recovered Natural Gas Revenue Decoupling Over Recovered Natural Gas Revenue Decoupling Over Recovered Natural Gas Revenue Decoupling Underrecovered Electric Supply cost Underrecovered Electric Supply cost Under recovered Electric Supply cost Non Bypassable Service Charges Non Bypassable Service Charges Non Bypassable Service Charges Schedule of Regulatory Assets Schedule of Regulatory Assets [Table Text Block] Schedule of Regulatory Liabilities Schedule of Regulatory Liabilities [Table Text Block] Purchase Of Receivables Purchase Of Receivables [Table Text Block] ComEd, PECO and BGE are required, under separate legislation and regulations in Illinois,Pennsylvania and Maryland, respectively, to purchase certain receivables from retail electric and natural gas suppliers. Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Classification Of Loss Exposure [Axis] Classification Of Loss Exposure [Axis] Loss Exposure [Domain] Loss Exposure [Domain] Investments [Member] Investments [Member] Contract Intangible Asset [Member] Contract Intangible Asset [Member] Payment Guarantee [Member] Payment Guarantee [Member] Asset Held In Trust Noncurrent [Member] Asset Held In Trust Noncurrent [Member] The total amount of cash and securities held by third party trustees pursuant to terms of debt instruments or other agreements as of the date of each statement of financial position presented, which can be used by the trustee only to pay the noncurrent portion of specified obligations. Variable Interest Entities By Type Of Entity [Axis] Variable Interest Entities By Type Of Entity [Axis] Variable Interest Entities By Type [Domain] Variable Interest Entities By Type [Domain] Commercial Agreement Variable Interest Entities [Member] Commercial Agreement Variable Interest Entities [Member] Equity Method Investment Variable Interest Entities [Member] Equity Method Investment Variable Interest Entities [Member] Scenario, Previously Reported [Member] Scenario, Previously Reported [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Total assets Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets Total liabilities Variable Interest Entity, Nonconsolidated, Carrying Amount, Liabilities Exelon's ownership interest in VIE Investments In Nonconsolidated Variable Interest Entities This element represents the total investments in variable interest entities as of the balance sheet date. Other ownership interests in VIE Other Nonconsolidated Variable Interest Entity Ownership Interests The carrying value of other ownership interests as of the balance sheet date. Registrants' maximum exposure to loss Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Assets Held-in-trust, Noncurrent Cash Flow Hedge By Derivative Instrument [Axis] Cash Flow Hedge By Derivative Instrument [Axis] Presents the types of cash flow hedges. Cash Flow Contract Type [Domain] Cash Flow Contract Type [Domain] Forms of cash flow hedges. Total Cash Flow Hedges [Member] Total Cash Flow Hedges [Member] Total cash flow hedges. Energy Related Hedges [Member] Energy Related Hedges [Member] Energy related cash flow hedges. Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Cash Flow Hedge Accumulated Other Comprehensive Income Gain Loss Cash Flow Hedge Accumulated Other Comprehensive Income Gain Loss Balance of gain (loss) in AOCI related to cash flow hedging instruments. Gain loss on interest rate swap treasury rate lock net of tax Gain loss on interest rate swap treasury rate lock net of tax Gain loss on interest rate swap treasury rate lock net of tax Net gain (loss) related to ineffective portion of changes in fair value of treasury rate locks Net gain (loss) related to ineffective portion of changes in fair value of treasury rate locks Net gain (loss) related to ineffective portion of changes in fair value of treasury rate locks Effective Portion Of Change In Fair Value Of Treasury Rate Lock Net Of Tax Effective Portion Of Change In Fair Value Of Treasury Rate Lock Net Of Tax The amount of net gains (losses) on a cash flow hedge reclassified in the period to earnings from accumulated other comprehensive income related to treasury rate locks, net of tax effect. Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net Derivative Instruments, Gain Reclassified from Accumulated OCI into Income, Effective Portion Derivative Instruments, Gain Reclassified from Accumulated OCI into Income, Effective Portion Effective portion of changes in fair value Effective portion of changes in fair value Changes to accumulated comprehensive income resulting from gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. A cash flow hedge is a hedge of the exposure to variability in the cash flows of a recognized asset or liability or a forecasted transaction that is attributable to a particular risk. Organization, Consolidation and Presentation of Financial Statements [Abstract] Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Error Corrections and Prior Period Adjustments Restatement [Line Items] Error Corrections and Prior Period Adjustments Restatement [Line Items] Purchased power and fuel from affiliates Total interest expense to affiliates, net Pretax decrease in operating and maintenance expense Electrical Transmission and Distribution Revenue Pretax increase in taxes other than income Income (Loss) from Equity Method Investments Fair Value of Financial Assets and Liabilities (Exelon, Generation, ComEd, PECO and BGE) Fair Value Disclosures [Text Block] Limerick and Three Mile Island Nuclear Units [Member] Limerick and Three Mile Island Nuclear Units [Member] Limerick and Three Mile Island Nuclear Units [Member] Asset Retirement Obligation, Period Increase (Decrease) Asset Retirement Obligation, Period Increase (Decrease) AssetRetirementObligationPeriodIncreaseSiteSecurity AssetRetirementObligationPeriodIncreaseSiteSecurity AssetRetirementObligationPeriodIncreaseSiteSecurity AssetRetirementObligationPeriodIncreaseSNF AssetRetirementObligationPeriodIncreaseSNF AssetRetirementObligationPeriodIncreaseSNF Other Income Other Income Nuclear Decommissioning Annual Recovery Current Nuclear Decommissioning Annual Recovery Current Current annual recovery of nuclear decommissioning costs from customers filed with state regulator Decommissioning Shortfall Decommissioning Shortfall Amount of decommissioning shortfall with recourse for collection from customers. Decommissioning Shortfall Percentage Decommissioning Shortfall Percentage Percent of additional decommissioning shortfall with recourse for collection from customers. Half Of Non Decommissioning Withdraw Half Of Non Decommissioning Withdraw Half Of Non Decommissioning Withdraw Decommissioning Fund Investments Decommissioning Liability, Noncurrent Additional NRC Funding Assurance Parent Guarantees Additional NRC Funding Assurance Parent Guarantees Additional guarantees potentially required by the Parent Company to cover the NRC underfunded position. NumberofOperatingReactors NumberofOperatingReactors NumberofOperatingReactors NuclearDecommissioningTrustFundEquityPercent NuclearDecommissioningTrustFundEquityPercent NuclearDecommissioningTrustFundEquityPercent SeniorNotes490June152015 [Member] SeniorNotes490June152015 [Member] SeniorNotes490June152015 [Member] Pollution Control Notes [Member] Pollution Control Notes [Member] Debt security from 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. Capital Lease Obligations [Member] Capital Lease Obligations [Member] Rate Stabilization Bonds, April 1, 2017 [Member] Rate Stabilization Bonds, April 1, 2017 [Member] AVSR DOE Member [Member] AVSR DOE Member [Member] AVSR DOE Member [Member] Continental Wind 6000 February 28, 2033 [Member] Kennett Square Capital Lease, 7.83%, September 20, 2020 [Member] FirstMortgageBond163January12014 [Member] FirstMortgageBond163January12014 [Member] Long term debt issued First Mortgage Bond 1.63 percent due January 1,2014 Clear Horizon solar [Member] Clear Horizon solar [Member] Clear Horizon solar [Member] Sacramento Solar [Member] Sacramento Solar [Member] Represents ownership in Sacramento Solar, a non-consolidated solar energy generator. MEDCO Tax-Exempt Bonds [Member] MEDCO Tax-Exempt Bonds [Member] SeniorSecuredNotes455Jun152015 [Member] SeniorSecuredNotes455Jun152015 [Member] SeniorSecuredNotes455Jun152015 [Member] UpstreamGasLending221July222016[Member] UpstreamGasLending221July222016[Member] Long Term Debt issued Up stream Gas Lending 2.21percent July 22,2016 Constellation2563Sept72030 [Member] Constellation2563Sept72030 [Member] Constellation2563Sept72030 [Member] FMBSeries470April152015 [Member] FMBSeries470April152015 [Member] FMBSeries470April152015 [Member] RateStabilization572April12016 [Member] RateStabilization572April12016 [Member] RateStabilization572April12016 [Member] Variable Interest Entity, Primary Beneficiary [Member] Variable Interest Entity, Primary Beneficiary [Member] Current Assets VariableInterestEntityConsolidatedCarryingAmountCurrentAssets VariableInterestEntityConsolidatedCarryingAmountCurrentAssets Non Current Assets Variable Interest Entity Consolidated Carrying Amount Non Current Assets VariableInterestEntityConsolidatedCarryingAmountNonCurrentAssets Total Assets Variable Interest Entity, Consolidated, Carrying Amount, Assets Current Liabilities Variable Interest Entity Consolidated Carrying Amount Current Liabilities Variable Interest Entity Consolidated Carrying Amount Current Liabilities Non Current Liabilities Variable Interest Entity Consolidated Carrying Amount Non Current Liabilities Variable Interest Entity Consolidated Carrying Amount Non Current Liabilities Total Liabilities Variable Interest Entity, Consolidated, Carrying Amount, Liabilities Assets Income Tax Additional Narrative Information [Table] Income Tax Additional Narrative Information [Table] Income Tax Additional Disclosure [Table] Nature of Uncertainty [Axis] Nature of Uncertainty [Axis] Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Nature of Uncertainty [Domain] Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Nature of Uncertainty [Domain] Settlement with Taxing Authority [Member] Settlement with Taxing Authority [Member] Income Tax Additional Narrative Information [Line Items] Income Tax Additional Narrative Information [Line Items] Income Tax Additional Disclosure [Line Items] Unrecognized Tax Benefits Unrecognized Tax Benefits Unrecognized tax benefits that if recognized would affect the effective tax rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Unrecognized Tax Benefits, Increase Resulting from Settlements with Taxing Authorities Unrecognized Tax Benefits, Increase Resulting from Settlements with Taxing Authorities Increase (Decrease) in Income Taxes Increase (Decrease) in Income Taxes Effective Income Tax Rate Reconciliation, Tax Settlement, Amount Effective Income Tax Rate Reconciliation, Tax Settlement, Amount Deferred tax gain under involuntary conversion provisions of the IRC Deferred Income Tax Gain In Voluntary Conversion The amount of income tax gain deferred in connection with a transaction meeting the involuntary conversion provisions of the Internal Revenue Code. IRS asserted penalties for understatement of tax Unrecognized Tax Benefits, Income Tax Penalties Expense Expected non-cash charge to earnings Unrecognized Tax Benefits, Interest on Income Taxes Accrued Non-cash equity contributions Non Cash Contributions From Parent The non cash impact of financing from parent as a source that is recorded as additional paid in capital. Potential tax and interest from a successful IRS challenge of the like-kind exchange transaction position Income Tax And Penalties From Potential Settle With Taxing Authority Represents the potential income tax and interest that could become currently payable in the event of a successful challenge by a taxing authority of an entity's income tax position. Early termination amount Gain (Loss) on Contract Termination Taxes Payable, Current Taxes Payable, Current Cash tax benefit (detriment) as a result of repair costs deduction Electric Transmission Distribution Property Repairs Deduction Cash Benefit Detriment Cash tax benefit (detriment) as a result of adopting the safe harbor method of tax accounting for repair costs associated with transmission and distribution property deduction. Unrecognized Tax Benefits, Interest on Income Taxes Accrued Increase in Unrecognized Tax Benefits is Reasonably Possible Increase in Unrecognized Tax Benefits is Reasonably Possible Decrease in Unrecognized Tax Benefits is Reasonably Possible Decrease in Unrecognized Tax Benefits is Reasonably Possible Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Fair Value, by Balance Sheet Grouping [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Reported Value Measurement [Member] Reported Value Measurement [Member] Estimate of Fair Value Measurement [Member] Estimate of Fair Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Lines of Credit, Fair Value Disclosure Lines of Credit, Fair Value Disclosure Short-term Debt Long-term debt (including amounts due within one year) Debt Instrument, Fair Value Disclosure DueToRelatedPartiesNoncurrentFairValue DueToRelatedPartiesNoncurrentFairValue DueToRelatedPartiesNoncurrentFairValue SNF obligation Spent Nuclear Fuel Obligations Fair Value Disclosure This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. Fair value of spent nuclear fuel obligations at the balance sheet date. Due to Related Parties, Noncurrent Fair Value of Financial Instruments, Policy [Policy Text Block] Fair Value of Financial Instruments, Policy [Policy Text Block] FairValueMeasurementsValuationTechniques policy [Policy Text Block] FairValueMeasurementsValuationTechniques policy [Policy Text Block] FairValueMeasurementsValuationTechniques policy [Policy Text Block] New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Description of New Accounting Pronouncements Not yet Adopted [Text Block] Description of New Accounting Pronouncements Not yet Adopted [Text Block] Schedule of Equity Method Investments [Table] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Financial Guarantee [Member] Financial Guarantee [Member] EDFI [Member] EDFI [Member] EdfiMember Electricite De France LLC [Member] Electricite De France LLC [Member] Electricite De France SA LLC Constellation Energy Group LLC [Member] Constellation Energy Group LLC [Member] Constellation Energy Group LLC Equity Method Investment, Ownership Percentage Equity Method Investment, Ownership Percentage Due from Affiliates Due from Affiliates Payments of Distributions to Affiliates Reduction To Net Income Attributable To Noncontrolling Interest ReductionToNetIncomeAttributableToNonControllingInterest ReductionToNetIncomeAttributableToNonControllingInterest Interest Rate On Distribution Interest Rate On Distribution Interest Rate On Distribution from CENG to Generation Related Party Purchase Of Nuclear Output By Third Party Percentage Related Party Purchase Of Nuclear Output By Third Party Percentage This element represents the percentage of nuclear output to be purchased by third party. Guarantor Obligations, Maximum Exposure, Undiscounted Guarantor Obligations, Maximum Exposure, Undiscounted Total equity investment earnings (losses) - CENG Income Loss From Equity Method Investment In Affiliate This item represents the entity's proportionate share for the period of the net income (loss) of its affiliate to which the equity method of accounting is applied. Allocation Of Federal Tax Benefit Under Tax Sharing Agreement Allocation Of Federal Tax Benefit Under Tax Sharing Agreement Federal income tax benefits allocated by a parent entity to its subsidiaries under a mutually agreed-upon tax sharing agreement, for which the goal is that the subsidiaries are responsible for the same amount of income tax expense or benefits that they would owe or receive had the subsidiary been separately subject to tax. Allocations of income tax benefits are treated as contributions of capital to the subsidiaries. Other Comprehensive Income (Loss), Tax Other Comprehensive Income (Loss), Tax Related Party Transaction Required Purchase Of Power Percentage Related Party Transaction Required Purchase Of Power Percentage Represents the required purchases of power from a related party, that is not sold to third parties, over the specified term of a power purchase agreement, percent. Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value Guarantor Obligations, Current Carrying Value Guarantor Obligations, Current Carrying Value Net Income (Loss) Attributable to Parent Net Income (Loss) Attributable to Parent Mergers, Acquisitions and Dispositions Business Combination Disclosure [Text Block] Supplemental Financial Information [Table] Supplemental Financial Information [Table] Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Low To Medium Risk [Member] Low To Medium Risk [Member] Represents valuation allowance for financing receivables that are expected to be uncollectible for customers deemed low to medium risk based on internal risk segmentation. Risk Level, Medium [Member] Risk Level, Medium [Member] Supplemental Financial Information Tables [Line Items] Supplemental Financial Information Tables [Line Items] Supplemental Financial Information. Smart Grid Grant Project Capital Expenditures Smart Grid Grant Project Capital Expenditures Represents the reimbursable smart grid investment grant project expenditures included in capital expenditures. Smart Grid Grant Reimbursements Smart Grid Grant Reimbursements DOE Smart Grid Investment Grant Reimbursement Financing Receivable, Net Financing Receivable, Net Financing Receivable, Allowance for Credit Losses Financing Receivable, Allowance for Credit Losses Other Segments [Member] Other Segments [Member] Utility Taxes Utility Taxes Revenue, excise or other taxes incurred by public utility companies. Comprehensive Income (Loss) Note [Text Block] Comprehensive Income (Loss) Note [Text Block] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Pepco Holdings [Member] Pepco Holdings [Member] Atlantic City Electric [Member] Atlantic City Electric [Member] Atlantic City Electric [Member] Integrys Energy Services [Member] Integrys Energy Services [Member] Integrys Energy Services [Member] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] MARYLAND MARYLAND Prince George County [Member] Prince George County [Member] Prince George County [Member] New Jersey Board Of Public Utilities [Member] New Jersey Board Of Public Utilities [Member] New Jersey Board Of Public Utilities [Member] Delaware Public Service Commission [Member] Delaware Public Service Commission [Member] Delaware Public Service Commission [Member] District of Columbia Public Service Commission [Member] District of Columbia Public Service Commission [Member] District of Columbia Public Service Commission [Member] Maryland Public Service Commission [Member] Maryland Public Service Commission [Member] Maryland Public Service Commission [Member] Project [Axis] Project [Axis] Project [Domain] Project [Domain] Workforce Development [Member] Workforce Development [Member] Workforce Development [Member] Energy Efficiency Program [Member] Energy Efficiency Program [Member] Energy Efficiency Program [Member] Rate Bill Credits [Member] Rate Bill Credits [Member] Rate Bill Credits [Member] Stability Fund [Member] Stability Fund [Member] Stability Fund [Member] Charitable Contributions [Member] Charitable Contributions [Member] Charitable Contributions [Member] OneTimeBillCredit [Member] OneTimeBillCredit [Member] OneTimeBillCredit [Member] LowIncomeAssistance [Member] LowIncomeAssistance [Member] LowIncomeAssistance [Member] Green Sustainability Fund [Member] Green Sustainability Fund [Member] Green Sustainability Fund [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Payments to Acquire Businesses and Interest in Affiliates [Abstract] Payments to Acquire Businesses and Interest in Affiliates [Abstract] Payments to Acquire Businesses, Gross Business Acquisition, Transaction Costs Business Acquisition, Transaction Costs Other Payments to Acquire Businesses Other Payments to Acquire Businesses Business Combination Proposed Customer Benefits Package Business Combination Proposed Customer Benefits Package Exelon and PHI have proposed a package of benefits to PHI utilities customers which results in a direct investment of more than $100 million Business Exit Costs Business Exit Costs Cash Funding From Non Core Asset Sale Cash Funding From Non Core Asset Sale Additional cash to be used in funding the Pepco Holdings Inc, merger by selling non-core asset Expected Debt Issuance Expected Debt Issuance Expected Debt Issuance to fund PHI acquisition Temporary Equity, Share Subscriptions Temporary Equity, Share Subscriptions Gain on Sale of Investments Gain on Sale of Investments Equity Method Investment, Net Sales Proceeds Equity Method Investment, Net Sales Proceeds Cash offered in exchange for each share of PHI stock Business Acquisition, Share Price Payments to Acquire Assets, Investing Activities Payments to Acquire Assets, Investing Activities Other Long-term Investments Other Long-term Investments Other noncurrent assets Significant Acquisitions and Disposals, Acquisition Costs or Sale Proceeds Business Combination, Consideration Transferred, Including Equity Interest in Acquiree Held Prior to Combination Expected Pre-Tax proceeds Expected Pre-Tax proceeds Expected Pre-Tax proceeds from Power Plant Assets Divestitures Assets Held-for-sale, at Carrying Value Disposal Group, Including Discontinued Operation, Assets Business Acquisition, Preacquisition Contingency, Amount of Settlement Business Acquisition, Preacquisition Contingency, Amount of Settlement Customer Loyalty Program Liability, Noncurrent Customer Loyalty Program Liability, Noncurrent Business Combination, Separately Recognized Transactions, Expenses and Losses Recognized Business Combination, Separately Recognized Transactions, Expenses and Losses Recognized Business Combination, Consideration Transferred, Liabilities Incurred Business Combination, Consideration Transferred, Liabilities Incurred Business Combination, Consideration Transferred Business Combination, Consideration Transferred BusinessAcquisitionPreacquisitionContingencyCapacityOfSettlementMwH BusinessAcquisitionPreacquisitionContingencyCapacityOfSettlementMwH BusinessAcquisitionPreacquisitionContingencyCapacityOfSettlementMwH Cost of Reimbursable Expense Cost of Reimbursable Expense Long-term Debt, Excluding Current Maturities Net present value of settlement amount Net present value of settlement amount Net present value of settlement amount Payments of Merger Related Costs, Financing Activities Payments of Merger Related Costs, Financing Activities Junior Subordinated Notes, Noncurrent Junior Subordinated Notes, Noncurrent Forward Contract Indexed to Issuer's Equity, Indexed Shares Forward Contract Indexed to Issuer's Equity, Indexed Shares Pension and non-pension postretirement benefit plans: Pension and Other Postretirement Benefit Expense [Abstract] Actuarial loss reclassified to periodic cost Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Tax Pension and non-pension postretirement benefit plans valuation adjustment Other Comprehensive Income Pension And Non Pension Postretirement Benefit Plan Valuation Adjustment Tax Tax effect of the pension and non-pension postretirement benefit plans valuation adjustment. Change in unrealized (gain) loss on cash flow hedges Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax Change in unrealized income on equity investments Other Comprehensive Income Unrealized Gain Loss On Equity Investments Arising During Period Tax Tax effect of the change in unrealized gains and losses from equity investments held during the period being reported on. Deferred compensation unit valuation adjustment Deferred Compensation Unit Valuation Adjustment tax Tax impact of Deferred Compensation Unit Valuation Adjustment Change in marketable securities Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Total Shares Issued, Price Per Share Temporary Equity, Par or Stated Value Per Share Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Cash, at Fair Value Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Cash, at Fair Value Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share RNF from external customers Segment Reporting Information Revenue Net Of Purchase Power And Fuel From External Customers Amount of revenues net of purchased power and fuel expense from external customers. Intersegment RNF Segment Reporting Information Intersegment Revenue Net Of Purchase Power And Fuel Segment Reporting Information, Intersegment Revenue Net of Purchased Power and Fuel Expense Segment Reporting Information Revenue Net of Purchase Power And Fuel Segment Reporting Information Revenue Net of Purchase Power And Fuel Amount of total revenues net of purchased power and fuel expense for Generation Amortization of Intangible Assets Purchase Of Receivables [Table] Purchase Of Receivables [Table] Purchase Of Receivables [Line Items] Purchase Of Receivables [Line Items] Purchased receivables Por Gross Receivables Outstanding gross receivables purchased under the POR program. Allowance for uncollectible accounts Por Allowance Allowance for uncollectible accounts on POR receivables Purchased receivables, net Por Net Receivables Outstanding net receivables purchased under the POR program. Discount rate Purchase of Receivables, Discount Rate related to Implementation Costs Purchase of Receivables, Discount Rate related to Implementation Costs Components of non-operating income and expenses Schedule of Other Nonoperating Income, by Component [Table Text Block] Components of depreciation, amortization and accretion, and other, net Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Cash Flow Supplemental Disclosures Cash Flow, Supplemental Disclosures [Text Block] Supplemental Balance Sheet Disclosures Supplemental Balance Sheet Disclosures [Text Block] Aggregate fair value of derivatives with credit-risk-related contingent features Derivative Liability, Fair Value, Gross Liability Contractual right of offset related to derivative assets Derivative Liability, Fair Value, Amount Offset Against Collateral Net liability position after contractual right of offset Net Asset Liability Position After Contractual Right Of Offset The net asset or liability position as of the balance sheet date after applying the contractual right of offset related to derivative instruments with credit-risk-related contingent features with the same counterparty under master netting agreements. Credit-risk-related contingent features stipulate that if the Company were to be downgraded or lose its investment grade credit rating (based on its senior unsecured debt rating), it would be required to provide additional collateral. Derivative, Collateral, Right to Reclaim Cash Derivative, Collateral, Right to Reclaim Securities Derivative, Collateral, Obligation to Return Cash Derivative, Collateral, Obligation to Return Securities Schedule Of Nuclear Decommissioning [Table] Schedule Of Nuclear Decommissioning [Line Items] Schedule Of Nuclear Decommissioning [Line Items] Nuclear decommissioning asset retirement obligation rollforward Schedule of Change in Asset Retirement Obligation [Table Text Block] Unrealized Gains (Losses) on nuclear decommissioning trust funds Unrealized Gains Losses On Nuclear Decommissioning Trust Funds [Table Text Block] Table providing unrealized gains and losses on NDT funds. Zion Station pledged assets Nuclear Decommissioning Pledged Assets [Table Text Block] Severance Benefits Obligations Balance Severance Benefits Obligations Balance Represents the liability recorded for severance benefits obligations as of the balance sheet date related to the corporate restructuring program. Payments Subsidiary Companies [Axis] Subsidiary Companies [Axis] Subsidiary Companies [Domain] Subsidiary Companies [Domain] Commonwealth Edison III [Member] Commonwealth Edison Three [Member] Commonwealth Edison Three [Member] PECO Trust III and IV [Member] PECO Trust Three and Four [Member] PECO Trust Three and Four [Member] Baltimore Gas and Electric Capital Trust II [Member] Baltimore Gas and Electric Capital Trust Two [Member] Baltimore Gas and Electric Capital Trust Two [Member] Financial Standby Letter of Credit [Member] Financial Standby Letter of Credit [Member] Guarantees Other Than Letters Of Credit and Nuclear Insurance Premiums [Member] Guarantees Other Than Letters Of Credit and Nuclear Insurance Premiums [Member] Guarantees other than letters of credit and nuclear insurance, including parental guarantees on behalf of subsidiaries and guarantees on surety bonds, performance contracts, energy marketing contracts, trust preferred securities, leases and indemnifications. Nuclear Insurance Premiums [Member] Nuclear Insurance Premiums [Member] Retrospective nuclear insurance premiums related to ANI under the Price-Anderson Act and participation in NEIL Trust Preferred Securities [Member] Trust Preferred Securities [Member] Preferred securities of a financing trust Underwriting Discount UnderwritingDiscount Underwriting Discount Estimated net exposure for commercial transaction obligations Estimated Net Exposure For Obligations Under Commercial Transactions Guarantees of certain subsidiary obligations to third parties in order to allow subsidiaries the flexibility needed to conduct business with counterparties without having to post other forms of collateral. Percentage owned finance subsidiary Consolidated Subsidiary Common Stock Ownership Percentage The percentage of ownership of common stock or equity participation in the consolidated subsidiary. Schedule of Defined Benefit Plans Disclosures Schedule of Defined Benefit Plans Disclosures [Table Text Block] Schedule Of Pension And Other Postretirement Benefit Costs Schedule Of Pension And Other Postretirement Benefit Costs [Table Text Block] This element may be used to capture the entire pension and other postretirement benefit expense table. Schedule Of Defined Contributions Schedule Of Defined Contributions [Table Text Block] This element may be used to capture the table of contributions by an employer to a defined contribution plan. Schedule of Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Schedule of Capital Leased Assets Schedule of Capital Leased Assets [Table Text Block] Multiemployer Plan Name [Axis] Multiemployer Plan Name [Axis] Multiemployer Plan Name [Domain] Multiemployer Plan Name [Domain] Supplemental Balance Sheet Information [Table] Schedule disclosing additional information about a registrants assets and liabilities in their statement of financial position. Supplemental Balance Sheet Information [Line Items] Supplemental Balance Sheet Information [Line Items] Supplemental Balance Sheet Information. Property, Plant and Equipment, Net [Abstract] Property, Plant and Equipment, Net [Abstract] Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Allowance for uncollectible accounts Allowance for Doubtful Accounts Receivable, Current Accumulated amortization of nuclear fuel Accumulated Amortization Nuclear Fuel The cumulative amount of amortization of nuclear fuel in the reactor core that has been recognized in the income statement. CurrentFinancingReceivableAllowanceForCreditLosses CurrentFinancingReceivableAllowanceForCreditLosses CurrentFinancingReceivableAllowanceForCreditLosses Fair Value Assets Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Summarization of information required and determined to be provided for purposes of reconciling beginning and ending balances of fair value measurements of assets and liabilities using significant unobservable inputs (Level 3). Such reconciliation, separately presenting changes during the period, at a minimum, may include: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (net); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs). Nuclear Decommissioning Trust Fund Investment Level Three Asset [Member] Nuclear Decommissioning Trust Fund Investment Level Three Asset [Member] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings, Description Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings, Description Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Earnings Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Earnings This element represents total gains or losses for the period (realized and unrealized), arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings. Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Description Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Description Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Included In Noncurrent Payables To Affiliates Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Included In Noncurrent Payables To Affiliates Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Included In Noncurrent Payables To Affiliates. Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract] Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract] Total realized / unrealized gains (losses) Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss [Abstract] This element represents total gains or losses for the period (realized and unrealized), arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3). Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Change In Collateral Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Change In Collateral Fair value measurement with unobservable inputs reconciliation recurring basis asset liability gain loss change in collateral. Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Value Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Value This element represents an asset or liability measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances. Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Total Gain Loss Included In Earnings Attributed To Changes In Unrealized Gains Losses Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Total Gain Loss Included In Earnings Attributed To Changes In Unrealized Gains Losses This element represents total unrealized gains or losses for the period, arising from the change in fair value related to assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), held as of the balance sheet date. Purchases, sales, issuances and settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, (Sales), Issuances, (Settlements) [Abstract] Purchases Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Transfers In Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Transfers In This element represents transfers in of assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period. Transfers into Level 3 Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers into Level 3 Transfers out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Transfers Out Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Transfers Out This element represents transfers out of assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period. Ending balance The amount of total losses included in income attributed to the change in unrealized gains (losses) related to assets and liabilities held Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Abstract] Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Abstract] Gain (loss) reclassified to results of operating due to the settlement of derivative contracts Derivative Gain Loss Reclassified To Earnings Net This element represents realized gains or losses that are reclassified to results of operations due to the settlement of all derivative contracts during the respective period. Decrease in Fair Value Adjustment Decrease in Fair Value Adjustment Decrease in Fair Value Adjustment Increase In Fair Value Adjustment Increase In Fair Value Adjustment Increase in fair value adjustment related to purchase accounting as a result of the exchnage offer. Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Nuclear Decommissioning Payable Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Nuclear Decommissioning Payable This element represents total gains or losses for the period (realized and unrealized), arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in a payable for nuclear power station decommissioning. Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Regulatory Assets Liabilities Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Regulatory Assets Liabilities This element represents total gains or losses for the period (realized and unrealized), arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in regulatory assets or liabilities. ImplicationsofPotentialEarlyPlantRetirements [Table Text Block] ImplicationsofPotentialEarlyPlantRetirements [Table Text Block] [Table Text Block] for ImplicationsofPotentialEarlyPlantRetirements [Table] Schedule of Short-term Debt Schedule of Short-term Debt [Table Text Block] Schedule Of Issuance Of Long Term Debt Schedule Of Issuance Of Long Term Debt [Table Text Block] Schedule itemizing the issuances of long-term debt during the period capturing: (1) type of debt issuance; (2) interest rate; (3) maturity date; (4) amount issued; and (5) the intended use of proceeds. Schedule of Long-term Debt Instruments Schedule of Long-term Debt Instruments [Table Text Block] Retirement and Redemptions of Current and Long-Term Debt Schedule of Extinguishment of Debt [Table Text Block] Other Unrecorded Amounts Other Unrecorded Amounts Long-term Purchase Commitment, Amount Long-term Purchase Commitment, Amount Distributed Energy Company [Member] Distributed Energy Company [Member] Distributed Energy Company [Member] RSB Bond Co LLC [Member] RSB Bond Co LLC [Member] Represents the consolidated variable interest entity of the reporting entity. Number of Variable Interest Entities not consolidated by equity holders Number Of Variable Interest Entities Not Consolidated The number of variable interest entities (VIEs) not consolidated. Number Of Variable Interest Entities Consolidated Number Of Variable Interest Entities Consolidated The number of variable interest entities (VIEs) consolidated. Remittance of payments received from customers for rate stabilization to BondCo. Amount Remitted To Variable Interest Entities On Rate Stabilization Bonds The amount remitted to variable interest entities for rate stabilization bonds. Equity Method Investment, Summarized Financial Information, Equity Excluding Noncontrolling Interests Equity Method Investment, Summarized Financial Information, Equity Excluding Noncontrolling Interests Note Receivable Note Receivable Note Receivable Sithe Guarantee [Member] Sithe Guarantee [Member] Guarantee related to Sithe. Nuclear insurance liability limit per incident Nuclear Insurance Annual Coverage Limit Annual coverage limit provided by the nuclear insurance arrangement for nuclear incident claims. Total of U.S. licensed nuclear reactors United States Licensed Nuclear Reactors Total The current total number of currently licensed nuclear reactors in the United States. Nuclear financial protection pool value Nuclear Insurance Financial Protection Pool Value Total funds available for nuclear insurance liability claims in a financial protection pool mandated by the Price-Anderson Act. Nuclear Insurance Financial Protection Pool Surcharge On Nuclear Incident Assessment Nuclear Insurance Financial Protection Pool Surcharge On Nuclear Incident Assessment Surcharge to the maximum assessment to be paid per nuclear reactor for nuclear incidents, under the financial protection pool mandated by the Price-Anderson Act. This legal surcharge may be applied, if needed, to legal costs associated with the nuclear incident. Maximum assessment mandated by Price-Anderson Act per nuclear reactor for a nuclear incident Nuclear Insurance Financial Protection Pool Maximum Assessment Maximum assessment to be paid per nuclear reactor for a nuclear incident, under the financial protection pool mandated by the Price-Anderson Act. This assessment is paid by each United States nuclear reactor operator over multiple years at a limited amount per year in the event of an incident at any United States nuclear reactor. Maximum liability per nuclear incident Nuclear Insurance Financial Protection Pool Nuclear Operator Maximum Total Assessment Maximum total assessment to be paid by a nuclear operator for a nuclear incident, under the financial protection pool mandated by the Price-Anderson Act. The total amount is calculated by multiplying the total nuclear reactors operated, by the maximum assessment per nuclear reactor. Cost of spent nuclear fuel disposal per kWh of net nuclear generation Cost Of Spent Nuclear Fuel Disposal Costs per kWh of net nuclear generation required to be paid to the Department of Energy per contracts under the Nuclear Waste Policy Act of 1982. Cost can be adjusted prospectively in order to ensure full cost recovery. Net Nuclear Fuel Disposal Fees Net Nuclear Fuel Disposal Fees Spent Nuclear Fuel Disposal Fees including Exelon's share of Salem and net of co-owner reimbursements Acquisition of interest in subsidiary Business Acquisition, Percentage of Voting Interests Acquired Sale of interest in subsidiary Business Divestiture Interest Divested The level of ownership or equity interest in a business divested in a business divestiture. Funds available for claim Funds available for claim Funds available for claim Recovery of Direct Costs Recovery of Direct Costs Current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets Nuclear decommissioning trust fund BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNDTFund BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNDTFund Property, plant and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Nuclear fuel BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNuclearFuel BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNuclearFuel Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Total assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Current liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities Asset retirement obligation Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Asset Retirment Obligations BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetRetirmentObligations Pension and other employee benefit obligations Postconfirmation, Pension Obligations Unamortized energy contract liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Liabilities Other liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Total liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Total net assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Supplemental Cash Flow Information [Table] Schedule disclosing additional information about a registrants statement of cash flows Indemnification Agreement [Member] Indemnification Agreement [Member] Supplemental Cash Flow Information [Line Items] Supplemental Cash Flow Information [Line Items] Supplemental Cash Flow Information [Line Items] Depreciation, Amortization and Accretion [Abstract] Depreciation, Amortization and Accretion, Net [Abstract] Property, plant and equipment Depreciation Regulatory assets Amortization of Regulatory Asset Amortization of intangible assets, net Amortization of Intangible Assets Net The net expense charged against earnings to allocate the cost of intangible assets and liabilities(nonphysical assets and liabilities not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. Amortization of energy contract assets and liabilities Energy Contract Amortization The amount of capitalized power supply and fuel accrual-based contract costs, that were acquired from Constellation, and were charged to purchased power and fuel expense during the period. Nuclear fuel Nuclear Fuel Amortization The amount of capitalized nuclear fuel costs that are charged to fuel expense during the period using the unit-of-production method. Asset retirement obligation accretion Total depreciation, amortization and accretion Other Non-Cash Operating Activities [Abstract] Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Gain (loss) on equity method investments Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Provision for uncollectible accounts Provision for Doubtful Accounts Stock-based compensation costs Share-based Compensation Other Decommissioning Related Activity Other Decommissioning Related Activity This item represents realized and unrealized gains (losses) for the period as a result of selling and holding marketable securities in nuclear decommissioning trust funds. Additionally, this item includes the elimination of operating revenues, asset retirement obligation accretion, asset retirement cost amortization, investment income and income taxes related to nuclear decommissioning trust fund activity. As a result of certain regulatory agreements for these nuclear decommissioning trust funds; upon completion of decommissioning activities, excess (shortfall of) funds will be refunded to (recovered from) rate payers through a regulated affiliate. Therefore, this activity is contractually eliminated within the income statement. Energy-related options Energy Related Options Represents the reclassification of energy-related option premiums to realized at settlement of contracts recorded in results of operations due to the settlement of the underlying transaction. Amortization of regulatory asset related to debt costs Amortization Of Regulatory Asset Debt Costs The expense charged against earnings during the period as a result of amortizing the losses on reacquired debt, which were capitalized as regulatory assets, over the life of the new debt issued to refinance the debt redemption or over the original life of the debt redeemed. Amortization of rate stabilization deferral Amortization Rate Stabilization Deferral Amortization of deferred costs under BGE rate stabilization Amortization of debt fair value adjustment Amortization Of Debt Fair Value Adjustment Amortization of debt fair value as part of purchase accounting related to the merger. Discrete impacts from EIMA Impacts Energy Infrastructure Modernization Act Non cash impact recorded to the income statement pursuant to an order and/or ruling by state regulators and/or courts. Amortization of debt costs Amortization Of Debt Costs This represents the amortization of unamortized debt expenses Non Cash Increase in Inventory Reserve Non Cash Increase in Inventory Reserve Non Cash Increase in Inventory Reserve Merger related commitments Inventory Write-down Inventory Write-down Other Noncash Income Expense Net Other Noncash Income Expense Net Other income and expenses included in net income that result in no cash inflows or outflows in the period, but increase or decrease net income and thus are removed when calculating net cash flow from operating activities using the indirect method. This element is used when there is not a more specific and appropriate element. Total other noncash operating activities Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities Changes In Other Assets and Liabilities [Abstract] Increase Decrease In Other Operating Capital Net [Abstract] Under/over-recovered energy and transmission costs Increase (Decrease) in over (under) Energy Recovery Other regulatory assets and liabilities Increase (Decrease) Other Regulatory Assets and Liabilities Cash flow impacts of other operating activities related to regulatory assets and liabilities Increase (Decrease) in Deposits Increase (Decrease) in Deposits Increase (Decrease) in Other Current Liabilities Increase (Decrease) in Other Current Liabilities Increase (Decrease) in Other Noncurrent Assets and Liabilities, Net Increase (Decrease) in Other Noncurrent Assets and Liabilities, Net Other current assets and liabilities Increase (Decrease) In Other Current Operating Assets And Liabilities The (increase) decrease during the reporting period in other current assets provided by or used in operating activities not otherwise defined in the taxonomy. Other noncurrent assets and liabilities Increase (Decrease) In Other Noncurrent Operating Assets Liabilities The net change during the reporting period in other non-current assets and liabilities provided by or used in operating activities not otherwise defined in the taxonomy. A positive value indicates a decrease in the net other non-current assets or an increase in the net other non-current liabilities, while a negative value indicates an increase in the net other non-current assets or a decrease in the net other non-current liabilities. Total changes in other assets and liabilities Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Non cash Fair Value Adjustment for CENG NonCashFairValueAdjustment NonCashFairValueAdjustment Debt exchange Debt Conversion, Original Debt, Amount Non Cash Debt Instrument Issued NonCashDebtInstrumentIssued NonCashDebtInstrumentIssued Capital Expenditures Incurred but Not yet Paid Capital Expenditures Incurred but Not yet Paid Indemnification of like-kind exchange position Non Cash Licensing Agreement Non Cash Licensing Agreement Non Cash Licensing Agreement Consolidated VIE dividend to non-controlling interest Total noncash investing and financing activities Noncash Investing And Financing Activities Total Total noncash investing and financing activities disclosed in supplemental financial information Costs Incurred, Asset Retirement Obligation Incurred Costs Incurred, Asset Retirement Obligation Incurred Stock Issued Stock Issued Schedule of Regulatory Assets [Table] Schedule of Regulatory Assets [Table] DSP Program [Member] DSP Program [Member] DSP Program [Member] Deferred Income Tax Charge [Member] Deferred Income Tax Charge [Member] AMI Meter Events [Member] AMI Meter Events [Member] This amount represents the cost value of the original smart meters, net of accumulated depreciation and DOE reimbursements, purchased for the first phase of smart meter deployment that will no longer be used, including installation and removal costs. Loss on Reacquired Debt [Member] Loss on Reacquired Debt [Member] Fair Value Of Long Term Debt [Member] Fair Value Of Long Term Debt [Member] Adjustment to fair value acquired debt; treated as deferred charges Fair Value Of Supply Contract [Member] Fair Value Of Supply Contract [Member] Adjustment to fair value supply contracts; treated as deferred charges Asset Retirement Obligation Costs [Member] RTO Startup Costs [Member] RTO Startup Costs [Member] Represents the amount of regulatory assets related to charges incurred by the entity to join a regional transmission organization. Under Recovered Uncollectible Accounts Expense [Member] Under Recovered Uncollectible Accounts Expense [Member] Represents the amount of regulatory assets related to under-recovered (over-recovered) uncollectible accounts expense. The basis for this amount is the difference between the entity's annual uncollectible accounts expense and amounts collected annually. Renewable Energy And Associated REC [Member] Renewable Energy And Associated REC [Member] Regulatory asset related to the recovery of renewable energy and associated RECs from retail customers with no mark up Deferred Storm Costs [Member] Deferred Storm Costs [Member] Significant storm costs deferred in a regulatory asset Electric Generation Related Regulatory Asset [Member] Electric Generation Related Regulatory Asset [Member] Costs recorded to a regulatory asset related to electric generation Rate Stabilization Deferral [Member] Rate Stabilization Deferral [Member] Costs deferred to a regulatory asset to stabilize customer rates ConservativeVoltageReductionProgram [Member] ConservativeVoltageReductionProgram [Member] ConservativeVoltageReductionProgram [Member] Regulatory Assets [Line Items] Regulatory Assets [Line Items] Current Noncurrent Regulatory Assets Environmental Restoration Costs Environmental Restoration Costs Environmental Restoration Costs UnderRecoveredElectricRevenueDecoupling UnderRecoveredElectricRevenueDecoupling UnderRecoveredElectricRevenueDecoupling Subsequent Event [Table] Subsequent Event [Table] Subsequent Event [Line Items] Subsequent Event [Line Items] Expected Cash Proceeds on Sale of Assets Expected Cash Proceeds on Sale of Assets Expected Cash Proceeds on Sale of Assets Expected Total Proceeds Working Capital Expected Total Proceeds Working Capital Expected Total Proceeds Working Capital Expected Assets Impairment Charge Expected Assets Impairment Charge Expected Assets Impairment Charge Expected After Tax Net Cash Proceeds Expected After Tax Net Cash Proceeds Expected After Tax Net Cash Proceeds Number of reportable segments Number of Reportable Segments Fair Value Tables [Line Items] Fair Value Tables [Line Items] Fair value of financial liabilities recorded at the carrying amount Fair Value, by Balance Sheet Grouping [Table Text Block] Assets and liabilities measured and recorded at fair value on recurring basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table Text Block] This element represents, for the fair value measurement of assets and liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (net); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs). Total realized and unrealized gains (losses) included in income for Level 3 assets and liabilities measured at fair value on a recurring basis Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Table Text Block] Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis, valuation technique Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Valuation Techniques [Table Text Block] Restricted cash Accounts receivable, net Accounts Receivable, Net [Abstract] Inventory Other current assets Total noncurrent assets Assets, Noncurrent Other current liabilities Pension obligation(a) Energy Marketing Contract Liabilities, Noncurrent Other noncurrent liabilities Net Capacity Purchases [Member] Net Capacity Purchases [Member] Power Purchases [Member] Power Purchases [Member] Transmission Rights Purchases [Member] Transmission Rights Purchases [Member] Renewable Energy Including Renewable Energy Credits [Member] Renewable Energy Including Renewable Energy Credits [Member] DSP Program Electric Procurement Contracts [Member] DSP Program Electric Procurement Contracts [Member] Represents the regulatory asset related to an entity's mark-to-market derivative liability position in electric supply procurement contracts. Alternative Energy Credits [Member] Alternative Energy Credits [Member] Curtailment Services [Member] Curtailment Services [Member] CapacityOffsets [Member] CapacityOffsets [Member] CapacityOffsets [Member] Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract] Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract] Operating Leases, Future Minimum Payments Receivable [Abstract] Operating Leases, Future Minimum Payments Receivable [Abstract] Thereafter Operating Leases, Future Minimum Payments Receivable, Thereafter Basis of Presentation (Exelon, Generation, ComEd, PECO and BGE) Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Retirement Benefits (Exelon, Generation, ComEd, PECO and BGE) Pension and Other Postretirement Benefits Disclosure [Text Block]