XML 41 R73.htm IDEA: XBRL DOCUMENT v2.4.1.9
Debt and Credit Agreements - Commercial Paper Borrowings Outstanding (Details) (Commercial Paper [Member], USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Exelon Generation Co L L C [Member]    
Short-term Debt [Line Items]    
Commercial paper borrowings $ 0us-gaap_CommercialPaper
/ dei_LegalEntityAxis
= exc_ExelonGenerationCoLLCMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_CommercialPaperMember		 $ 0us-gaap_CommercialPaper
/ dei_LegalEntityAxis
= exc_ExelonGenerationCoLLCMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_CommercialPaperMember
Commonwealth Edison Co [Member]    
Short-term Debt [Line Items]    
Commercial paper borrowings 283us-gaap_CommercialPaper
/ dei_LegalEntityAxis
= exc_CommonwealthEdisonCoMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_CommercialPaperMember		 304us-gaap_CommercialPaper
/ dei_LegalEntityAxis
= exc_CommonwealthEdisonCoMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_CommercialPaperMember
Baltimore Gas and Electric Company [Member]    
Short-term Debt [Line Items]    
Commercial paper borrowings $ 0us-gaap_CommercialPaper
/ dei_LegalEntityAxis
= exc_BaltimoreGasAndElectricCompanyMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_CommercialPaperMember		 $ 120us-gaap_CommercialPaper
/ dei_LegalEntityAxis
= exc_BaltimoreGasAndElectricCompanyMember
/ us-gaap_ShortTermDebtTypeAxis
= us-gaap_CommercialPaperMember