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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 false 49 Baltimore Gas and Electric Company | 5.90% Notes, due October 1, 2016 0 na true na na No definition available. false true false false false false false false false false false http://www.constellation.com/role/disclosurecapitalizationdetails false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false false 9 USD true false false false us-gaap_SubsidiariesMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_SubsidiariesMember dei_LegalEntityAxis explicitMember false false ceg_NotesDueOctober2016At5.90PercentMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NotesDueOctober2016At5.90PercentMember us-gaap_LongtermDebtTypeAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ false 10 USD true false false false us-gaap_SubsidiariesMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_SubsidiariesMember dei_LegalEntityAxis explicitMember false false ceg_NotesDueOctober2016At5.90PercentMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NotesDueOctober2016At5.90PercentMember us-gaap_LongtermDebtTypeAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ na No definition available. 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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 false 85 Baltimore Gas and Electric Company | Medium-term notes, Series E 0 na true na na No definition available. false true false false false false false false false false false http://www.constellation.com/role/disclosurecapitalizationdetails false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false false 15 USD true false false false us-gaap_SubsidiariesMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_SubsidiariesMember dei_LegalEntityAxis explicitMember false false us-gaap_MediumTermNotesMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_MediumTermNotesMember us-gaap_LongtermDebtTypeAxis explicitMember Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 16 USD true false false false us-gaap_SubsidiariesMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_SubsidiariesMember dei_LegalEntityAxis explicitMember false false us-gaap_MediumTermNotesMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_MediumTermNotesMember us-gaap_LongtermDebtTypeAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. 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No authoritative reference available. false 97 Nonregulated businesses 0 na true na na No definition available. false true false false false false false false false false false http://www.constellation.com/role/disclosurecapitalizationdetails false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false false 17 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 18 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 $ na No definition available. 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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. 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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. 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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. 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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. 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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. 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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. 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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 false 193 Nonregulated businesses | 5.00% Mortgage note, due June 15, 2010 0 na true na na No definition available. false true false false false false false false false false false http://www.constellation.com/role/disclosurecapitalizationdetails false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false false 30 USD true false false false ceg_NonRegulatedBusinessMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NonRegulatedBusinessMember dei_LegalEntityAxis explicitMember false false ceg_MortgageNoteDueJune2010At5.00PercentMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi ceg_MortgageNoteDueJune2010At5.00PercentMember us-gaap_LongtermDebtTypeAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ false 31 USD true false false false ceg_NonRegulatedBusinessMember dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi ceg_NonRegulatedBusinessMember dei_LegalEntityAxis explicitMember false false ceg_MortgageNoteDueJune2010At5.00PercentMember us-gaap_LongtermDebtTypeAxis xbrldi http://xbrl.org/2006/xbrldi ceg_MortgageNoteDueJune2010At5.00PercentMember us-gaap_LongtermDebtTypeAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 $ na No definition available. 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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. 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