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Fair Value of Financial Assets and Liabilities - Fair Value Measurement of Assets and Liabilities, Recurring (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]      
Derivative, Notional Amount $ 3,481 $ 4,018  
Unrealized Gain (Loss) on Investments (160) 186 $ 0
Market-to-market derivative liabilities, current 18 33  
Derivative Liability, Noncurrent 201 268  
Cash and Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 464 237  
Restricted cash [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 49 39  
Other assets      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 44 53  
Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 524 558  
Assets, Fair Value Disclosure 752 776  
Deferred Compensation Liability, Current and Noncurrent (131) (121)  
Total liabilities (350) (422)  
Fair Value, Net Asset (Liability) 402 354  
Fair Value, Recurring [Member] | Economic Hedging Instrument Liabilites [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Total mark-to-market derivative liabilities (219) (301)  
Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 228 218  
Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 60 59  
Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 60 54  
Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 10 11  
Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 98 94  
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 524 558  
Assets, Fair Value Disclosure 644 671  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 644 671  
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Economic Hedging Instrument Liabilites [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Total mark-to-market derivative liabilities 0 0  
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 120 113  
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 60 59  
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 60 54  
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 71 71  
Deferred Compensation Liability, Current and Noncurrent (131) (121)  
Total liabilities (131) (121)  
Fair Value, Net Asset (Liability) (60) (50)  
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Economic Hedging Instrument Liabilites [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Total mark-to-market derivative liabilities 0 0  
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 71 71  
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 10 11  
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 61 60  
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 37 34  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities (219) (301)  
Fair Value, Net Asset (Liability) (182) (267)  
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Economic Hedging Instrument Liabilites [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Total mark-to-market derivative liabilities (219) (301)  
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 37 34  
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 37 34  
Commonwealth Edison Co [Member]      
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]      
Market-to-market derivative liabilities, current 18 33  
Derivative Liability, Noncurrent 201 268  
Commonwealth Edison Co [Member] | Cash and Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 105 83  
Commonwealth Edison Co [Member] | Restricted cash [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 42 37  
Commonwealth Edison Co [Member] | Other assets      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 43 43  
Commonwealth Edison Co [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 237 285  
Assets, Fair Value Disclosure 237 285  
Total mark-to-market derivative liabilities (219) (301)  
Deferred Compensation Liability, Current and Noncurrent (10) (8)  
Total liabilities (229) (309)  
Fair Value, Net Asset (Liability) 8 (24)  
Commonwealth Edison Co [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Commonwealth Edison Co [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Commonwealth Edison Co [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 237 285  
Assets, Fair Value Disclosure 237 285  
Total mark-to-market derivative liabilities 0 0  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 237 285  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 0 0  
Total mark-to-market derivative liabilities 0 0  
Deferred Compensation Liability, Current and Noncurrent (10) (8)  
Total liabilities (10) (8)  
Fair Value, Net Asset (Liability) (10) (8)  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 3 [Member]      
Footnotes To Fair Value Assets And Liabilities Measured On Recurring Basis [Abstract]      
Market-to-market derivative liabilities, current 18 33  
Derivative Liability, Noncurrent 201 268  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 0 0  
Total mark-to-market derivative liabilities (219) (301)  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities (219) (301)  
Fair Value, Net Asset (Liability) (219) (301)  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Commonwealth Edison Co [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
PECO Energy Co [Member] | Cash and Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 35 18  
PECO Energy Co [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 9 8  
Assets, Fair Value Disclosure 36 30  
Total mark-to-market derivative liabilities 0 0  
Deferred Compensation Liability, Current and Noncurrent (9) (9)  
Total liabilities (9) (9)  
Fair Value, Net Asset (Liability) 27 21  
PECO Energy Co [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 27 22  
PECO Energy Co [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 11 9  
PECO Energy Co [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 16 13  
PECO Energy Co [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 9 8  
Assets, Fair Value Disclosure 20 17  
Total mark-to-market derivative liabilities 0 0  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 20 17  
PECO Energy Co [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 11 9  
PECO Energy Co [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 11 9  
PECO Energy Co [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
PECO Energy Co [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 16 13  
Total mark-to-market derivative liabilities 0 0  
Deferred Compensation Liability, Current and Noncurrent (9) (9)  
Total liabilities (9) (9)  
Fair Value, Net Asset (Liability) 7 4  
PECO Energy Co [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 16 13  
PECO Energy Co [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
PECO Energy Co [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 16 13  
PECO Energy Co [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 0 0  
Total mark-to-market derivative liabilities 0 0  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 0 0  
PECO Energy Co [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
PECO Energy Co [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
PECO Energy Co [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Baltimore Gas and Electric Company [Member] | Cash and Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 51 24  
Baltimore Gas and Electric Company [Member] | Restricted cash [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 4 1  
Baltimore Gas and Electric Company [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 120  
Assets, Fair Value Disclosure 14 130  
Total mark-to-market derivative liabilities 0 0  
Deferred Compensation Liability, Current and Noncurrent (7) (5)  
Total liabilities (7) (5)  
Fair Value, Net Asset (Liability) 7 125  
Baltimore Gas and Electric Company [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 14 10  
Baltimore Gas and Electric Company [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 14 10  
Baltimore Gas and Electric Company [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 120  
Assets, Fair Value Disclosure 14 130  
Total mark-to-market derivative liabilities 0 0  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 14 130  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 14 10  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 14 10  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 0 0  
Total mark-to-market derivative liabilities 0 0  
Deferred Compensation Liability, Current and Noncurrent (7) (5)  
Total liabilities (7) (5)  
Fair Value, Net Asset (Liability) (7) (5)  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 0 0  
Total mark-to-market derivative liabilities 0 0  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 0 0  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Baltimore Gas and Electric Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Pepco Holdings LLC [Member] | Cash and Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 100 74  
Pepco Holdings LLC [Member] | Restricted cash [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 3 0  
Pepco Holdings LLC [Member] | Other assets      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 10  
Pepco Holdings LLC [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 110 86  
Assets, Fair Value Disclosure 255 226  
Deferred Compensation Liability, Current and Noncurrent (18) (17)  
Total liabilities (18) (17)  
Fair Value, Net Asset (Liability) 237 209  
Pepco Holdings LLC [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 145 140  
Pepco Holdings LLC [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 59 55  
Pepco Holdings LLC [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 14 14  
Pepco Holdings LLC [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 10 11  
Pepco Holdings LLC [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 62 60  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 110 86  
Assets, Fair Value Disclosure 183 155  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 183 155  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 73 69  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 59 55  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 14 14  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 37 37  
Deferred Compensation Liability, Current and Noncurrent (18) (17)  
Total liabilities (18) (17)  
Fair Value, Net Asset (Liability) 19 20  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 37 37  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 10 11  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 27 26  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 35 34  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 35 34  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 35 34  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mutual Fund [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Pepco Holdings LLC [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 35 34  
Potomac Electric Power Company [Member] | Cash and Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 34 30  
Potomac Electric Power Company [Member] | Restricted cash [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 3 0  
Potomac Electric Power Company [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 31 35  
Assets, Fair Value Disclosure 151 150  
Deferred Compensation Liability, Current and Noncurrent (2) (2)  
Total liabilities (2) (2)  
Fair Value, Net Asset (Liability) 149 148  
Potomac Electric Power Company [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 120 115  
Potomac Electric Power Company [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 58 53  
Potomac Electric Power Company [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   2  
Potomac Electric Power Company [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 62 60  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 31 35  
Assets, Fair Value Disclosure 89 88  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 89 88  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 58 53  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 58 53  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   0  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 27 28  
Deferred Compensation Liability, Current and Noncurrent (2) (2)  
Total liabilities (2) (2)  
Fair Value, Net Asset (Liability) 25 26  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 27 28  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   2  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 27 26  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 35 34  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 35 34  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 35 34  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   0  
Potomac Electric Power Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 35 34  
Delmarva Power & Light Company [Member] | Cash and Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 28 15  
Delmarva Power & Light Company [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 43 0  
Assets, Fair Value Disclosure 43 0  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 43 0  
Delmarva Power & Light Company [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   0  
Delmarva Power & Light Company [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 43 0  
Assets, Fair Value Disclosure 43 0  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 43 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 0 0  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 0 0  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   0  
Delmarva Power & Light Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Cash and Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 29 17  
Atlantic City Electric Company [Member] | Other assets      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 10  
Atlantic City Electric Company [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 13  
Assets, Fair Value Disclosure 0 13  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 0 13  
Atlantic City Electric Company [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   0  
Atlantic City Electric Company [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 13  
Assets, Fair Value Disclosure 0 13  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 0 13  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 0 0  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 0 0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Cash and Cash Equivalents, Fair Value Disclosure 0 0  
Assets, Fair Value Disclosure 0 0  
Deferred Compensation Liability, Current and Noncurrent 0 0  
Total liabilities 0 0  
Fair Value, Net Asset (Liability) 0 0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure 0 0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure   0  
Atlantic City Electric Company [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]      
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]      
Investments, Fair Value Disclosure $ 0 $ 0