2.2.0.7 true Capitalization (Details 5) (USD $) 4094 - Disclosure - Capitalization (Details 5) true false In Millions false false 1 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 2 USD true false false false us-gaap_SubsidiariesMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_SubsidiariesMember dei_LegalEntityAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ false 3 USD true false false false us-gaap_SubsidiariesMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_SubsidiariesMember dei_LegalEntityAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ false 4 USD true false false false ceg_NonRegulatedBusinessMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NonRegulatedBusinessMember dei_LegalEntityAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 5 USD true false false false ceg_NonRegulatedBusinessMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NonRegulatedBusinessMember dei_LegalEntityAxis explicitMember false false us-gaap_InterestRateSwapMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_InterestRateSwapMember us-gaap_LongtermDebtTypeAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 6 true false false false ceg_NonRegulatedBusinessMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NonRegulatedBusinessMember dei_LegalEntityAxis explicitMember false false ceg_LoansUnderCreditAgreementsMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi ceg_LoansUnderCreditAgreementsMember us-gaap_LongtermDebtTypeAxis explicitMember Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 false 7 true false false false ceg_NonRegulatedBusinessMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NonRegulatedBusinessMember dei_LegalEntityAxis explicitMember false false ceg_LoansUnderCreditAgreementsMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi ceg_LoansUnderCreditAgreementsMember us-gaap_LongtermDebtTypeAxis explicitMember Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 false 8 true false false false ceg_NonRegulatedBusinessMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NonRegulatedBusinessMember dei_LegalEntityAxis explicitMember false false ceg_TaxExemptDebtMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi ceg_TaxExemptDebtMember us-gaap_LongtermDebtTypeAxis explicitMember Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 false 9 true false false false ceg_NonRegulatedBusinessMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NonRegulatedBusinessMember dei_LegalEntityAxis explicitMember false false ceg_TaxExemptDebtMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi ceg_TaxExemptDebtMember us-gaap_LongtermDebtTypeAxis explicitMember Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 false 10 true false false false ceg_NonRegulatedBusinessMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NonRegulatedBusinessMember dei_LegalEntityAxis explicitMember false false ceg_FixedRateDebtConvertedToFloatingDebtMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi ceg_FixedRateDebtConvertedToFloatingDebtMember us-gaap_LongtermDebtTypeAxis explicitMember Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 false 11 true false false false ceg_NonRegulatedBusinessMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NonRegulatedBusinessMember dei_LegalEntityAxis explicitMember false false ceg_FixedRateDebtConvertedToFloatingDebtMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi ceg_FixedRateDebtConvertedToFloatingDebtMember us-gaap_LongtermDebtTypeAxis explicitMember Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 false 12 USD true false false false ceg_ConsolidatedEntitiesExcludingBGEMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi ceg_ConsolidatedEntitiesExcludingBGEMember dei_LegalEntityAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ 5 Maturities of Long-Term Debt 3 us-gaap_MaturitiesOfLongTermDebtAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false xbrli:stringItemType string No definition available. false 6 2010 4 us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths us-gaap true credit instant No definition available. false false false false false false false false false false false terselabel false 1 true true false false 56900000 56.9 false false false 2 true true false false 56500000 56.5 true false false 3 false false false false 0 0 true false false 4 true true false false 400000 0.4 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false xbrli:monetaryItemType monetary Amount of long-term debt maturing within the next twelve months following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 47 -Paragraph 10 -Subparagraph b false 7 2011 4 us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo us-gaap true credit instant No definition available. false false false false false false false false false false false terselabel false 1 false true false false 81800000 81.8 false false false 2 false true false false 81700000 81.7 true false false 3 false false false false 0 0 true false false 4 false true false false 100000 0.1 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false xbrli:monetaryItemType monetary Amount of long-term debt maturing in year two following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 47 -Paragraph 10 -Subparagraph b false 8 2012 4 us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree us-gaap true credit instant No definition available. false false false false false false false false false false false terselabel false 1 false true false false 923800000 923.8 false false false 2 false true false false 172500000 172.5 true false false 3 false false false false 0 0 true false false 4 false true false false 28700000 28.7 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false true false false 722600000 722.6 true false false xbrli:monetaryItemType monetary Amount of long-term debt maturing in year three following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 47 -Paragraph 10 -Subparagraph b false 9 2013 4 us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour us-gaap true credit instant No definition available. false false false false false false false false false false false terselabel false 1 false true false false 466600000 466.6 false false false 2 false true false false 466600000 466.6 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false xbrli:monetaryItemType monetary Amount of long-term debt maturing in year four following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 47 -Paragraph 10 -Subparagraph b false 10 2014 4 us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive us-gaap true credit instant No definition available. false false false false false false false false false false false terselabel false 1 false true false false 90400000 90.4 false false false 2 false true false false 70400000 70.4 true false false 3 false false false false 0 0 true false false 4 false true false false 20000000 20.0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false xbrli:monetaryItemType monetary Amount of long-term debt maturing in year five following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 47 -Paragraph 10 -Subparagraph b false 11 Thereafter 4 us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive us-gaap true credit instant No definition available. false false false false false false false false false false false terselabel false 1 false true false false 3255400000 3255.4 false false false 2 false true false false 1352400000 1352.4 true false false 3 false false false false 0 0 true false false 4 false true false false 187000000 187.0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false true false false 1716000000 1716.0 true false false xbrli:monetaryItemType monetary Amount of long-term debt maturities after year five following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 47 -Paragraph 10 -Subparagraph b false 12 Total 4 us-gaap_DebtInstrumentCarryingAmount us-gaap true credit instant No definition available. false false false false false false false false false false false totallabel false 1 false true false false 4874900000 4874.9 false false false 2 false true false false 2200100000 2200.1 true false false 3 false false false false 0 0 true false false 4 false true false false 236200000 236.2 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false true false false 2438600000 2438.6 true false false xbrli:monetaryItemType monetary Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date before deducting unamortized discount or premiums (if any). May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number APB14-1 -Paragraph 31 -Subparagraph b Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 true 13 Weighted-Average Interest Rates for Variable Rate Debt 3 ceg_WeightedAverageInterestRatesForVariableRateDebtAbstract ceg false na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false xbrli:stringItemType string No definition available. false 14 Weighted average interest rates for variable rate debt outstanding (in hundredths) 4 us-gaap_DebtInstrumentInterestRateDuringPeriod us-gaap true na duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false true false false 0.0450 0.0450 true false false 7 false true false false 0.0261 0.0261 true false false 8 false true false false 0.0122 0.0122 true false false 9 false true false false 0.0317 0.0317 true false false 10 false true false false 0.0230 0.0230 true false false 11 false true false false 0.0488 0.0488 true false false 12 false false false false 0 0 true false false us-types:percentItemType pure The average effective interest rate during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 false 15 Notional amount of interest rate swaps 4 us-gaap_NotionalAmountOfInterestRateDerivatives us-gaap true debit instant No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false 5 true true false false 400000000 400.0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false xbrli:monetaryItemType monetary Aggregate notional amount of interest rate derivatives, which relates to the currency amount specified in the interest rate derivative instruments. No authoritative reference available. false 16 Dividend Restrictions 3 us-gaap_DisclosureOfRestrictionsOnDividendsLoansAndAdvancesDisclosureAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false xbrli:stringItemType string No definition available. false 17 BGE's minimum equity ratio required after dividend payments as calculated pursuant to the Maryland PSC's ratemaking precedents 4 ceg_EquityRatioAfterDividendPaymentMinimum ceg false na instant This element represents the required equity ratio after dividend payments, as calculated pursuant to the Maryland PSC's... false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 0.48 0.48 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false us-types:percentItemType pure This element represents the required equity ratio after dividend payments, as calculated pursuant to the Maryland PSC's ratemaking precedents, minimum. No authoritative reference available. false 18 Number of major credit rating agencies that would have to rate BGE's senior unsecured credit rating below investment grade for there to be a dividend payment restriction 4 ceg_RequiredMajorCreditRatingAgenciesToRateBelowInvestmentGradeForDividendPaymentRestrictions ceg false na instant This element represents the number of major credit rating agencies that would have to rate BGE's senior unsecured credit... false false false false false false false false false false false terselabel false 1 false true false false 2 2 false false false 2 false false false false 0 0 true false false 3 false true false false 2 2 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false xbrli:integerItemType integer This element represents the number of major credit rating agencies that would have to rate BGE's senior unsecured credit rating below investment grade for there to be a dividend payment restriction. No authoritative reference available. false 19 Number of major credit rating agencies 4 ceg_MajorExternalCreditRatingAgenciesNumber ceg false na instant The major external credit rating agencies, number. false false false false false false false false false false false terselabel false 1 false true false false 3 3 false false false 2 false false false false 0 0 true false false 3 false true false false 3 3 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false xbrli:integerItemType integer The major external credit rating agencies, number. No authoritative reference available. false 12 15 false HundredThousands UnKnown UnKnown false true