v3.26.1
Fair Value of Financial Assets and Liabilities - Fair Value Measurements of Assets and Liabilities, Recurring and Nonrecurring (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Mark-to-market derivative liabilities $ 23 $ 30
Mark-to-market derivative liabilities (noncurrent liabilities) 105 106
Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 2,026 825
Assets, Fair Value Disclosure 2,320 1,106
Deferred Compensation Liability, Current and Noncurrent (66) (71)
Total liabilities 194 206
Fair Value, Net Asset (Liability) 2,126 900
Fair Value, Recurring [Member] | Mark-to-Market Derivative Liabilities    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total mark-to-market derivative liabilities (128) (131)
Fair Value, Recurring [Member] | Derivatives Designated as Hedging Instruments Liabilities    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total mark-to-market derivative liabilities 0 (4)
Fair Value, Recurring [Member] | Interest Rate Derivative Liabilities    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total mark-to-market derivative liabilities 0 (4)
Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:CashAndCashEquivalentsAtCarryingValue    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 180 180
Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:RestrictedCash    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 224 196
Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:RestrictedCashAndInvestmentsNoncurrent    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 9 50
Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 291 278
Fair Value, Recurring [Member] | Cash Equivalents [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 108 101
Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 77 71
Fair Value, Recurring [Member] | Fixed Income Investments [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 6 6
Fair Value, Recurring [Member] | 6311 Life Insurance [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 100 100
Fair Value, Recurring [Member] | Designated as Hedging Instrument [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total derivative assets 3 3
Fair Value, Recurring [Member] | Interest Rate Derivative Assets    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total derivative assets 3 3
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 2,026 825
Assets, Fair Value Disclosure 2,211 997
Deferred Compensation Liability, Current and Noncurrent 0 0
Total liabilities 0 0
Fair Value, Net Asset (Liability) 2,211 997
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mark-to-Market Derivative Liabilities    
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] | Derivatives Designated as Hedging Instruments Liabilities    
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] | Interest Rate Derivative Liabilities    
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 185 172
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 108 101
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 77 71
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 1 [Member] | Fair Value, Recurring [Member] | Designated as Hedging Instrument [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total derivative assets 0 0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Interest Rate Derivative Assets    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total derivative assets 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 equivalents 0 0
Assets, Fair Value Disclosure 90 88
Deferred Compensation Liability, Current and Noncurrent (66) (71)
Total liabilities 66 75
Fair Value, Net Asset (Liability) 24 13
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mark-to-Market Derivative Liabilities    
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] | Derivatives Designated as Hedging Instruments Liabilities    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total mark-to-market derivative liabilities 0 (4)
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Interest Rate Derivative Liabilities    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total mark-to-market derivative liabilities 0 (4)
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 87 85
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 Funds [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 6 6
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 81 79
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Designated as Hedging Instrument [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total derivative assets 3 3
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Interest Rate Derivative Assets    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total derivative assets 3 3
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 0 0
Assets, Fair Value Disclosure 19 21
Deferred Compensation Liability, Current and Noncurrent 0 0
Total liabilities 128 131
Fair Value, Net Asset (Liability) (109) (110)
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mark-to-Market Derivative Liabilities    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total mark-to-market derivative liabilities (128) (131)
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Derivatives Designated as Hedging Instruments Liabilities    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total mark-to-market derivative liabilities 0 0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Interest Rate Derivative Liabilities    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total mark-to-market derivative liabilities 0 0
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 19 21
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 Funds [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 19 21
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Designated as Hedging Instrument [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total derivative assets 0 0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Interest Rate Derivative Assets    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Total derivative assets 0 0
Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Assets, Fair Value Disclosure 0 0
Total liabilities 0 0
Commonwealth Edison Co    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Mark-to-market derivative liabilities 23 25
Mark-to-market derivative liabilities (noncurrent liabilities) 105 106
Commonwealth Edison Co | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 949 393
Total derivative assets 0  
Assets, Fair Value Disclosure 949 393
Total mark-to-market derivative liabilities (128) (131)
Deferred Compensation Liability, Current and Noncurrent (9) (9)
Total liabilities 137 140
Fair Value, Net Asset (Liability) 812 253
Mark-to-market derivative liabilities 23 25
Mark-to-market derivative liabilities (noncurrent liabilities) 105 106
Commonwealth Edison Co | Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:CashAndCashEquivalentsAtCarryingValue    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 75 77
Commonwealth Edison Co | Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:RestrictedCash    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 222 193
Commonwealth Edison Co | Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:RestrictedCashAndInvestmentsNoncurrent    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 9 50
Commonwealth Edison Co | 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 | Fair Value, Recurring [Member] | Cash Equivalents [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0  
Commonwealth Edison Co | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0 0
Commonwealth Edison Co | 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 | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 949 393
Assets, Fair Value Disclosure 949 393
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) 949 393
Commonwealth Edison Co | 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 | 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  
Commonwealth Edison Co | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0 0
Commonwealth Edison Co | 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 | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 0 0
Assets, Fair Value Disclosure 0 0
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) (9) (9)
Commonwealth Edison Co | 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 | 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  
Commonwealth Edison Co | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0 0
Commonwealth Edison Co | 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 | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 0 0
Assets, Fair Value Disclosure 0 0
Total mark-to-market derivative liabilities (128) (131)
Deferred Compensation Liability, Current and Noncurrent 0 0
Total liabilities 128 131
Fair Value, Net Asset (Liability) (128) (131)
Commonwealth Edison Co | 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 | 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  
Commonwealth Edison Co | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0 0
Commonwealth Edison Co | 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
Commonwealth Edison Co | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Assets, Fair Value Disclosure 0 0
Total liabilities 0 0
PECO Energy Co | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 2 93
Assets, Fair Value Disclosure 43 131
Total mark-to-market derivative liabilities 0 0
Deferred Compensation Liability, Current and Noncurrent (7) (8)
Total liabilities 7 8
Fair Value, Net Asset (Liability) 36 123
PECO Energy Co | Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:CashAndCashEquivalentsAtCarryingValue    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 37 23
PECO Energy Co | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 41 38
PECO Energy Co | Fair Value, Recurring [Member] | Cash Equivalents [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 2  
PECO Energy Co | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 14 13
PECO Energy Co | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 25 25
PECO Energy Co | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 2 93
Assets, Fair Value Disclosure 18 106
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) 18 106
PECO Energy Co | 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 16 13
PECO Energy Co | 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 2  
PECO Energy Co | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 14 13
PECO Energy Co | 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 | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 0 0
Assets, Fair Value Disclosure 25 25
Total mark-to-market derivative liabilities 0 0
Deferred Compensation Liability, Current and Noncurrent (7) (8)
Total liabilities 7 8
Fair Value, Net Asset (Liability) 18 17
PECO Energy Co | 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 25 25
PECO Energy Co | 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  
PECO Energy Co | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0 0
PECO Energy Co | 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 25 25
PECO Energy Co | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 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 | 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 | 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  
PECO Energy Co | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0 0
PECO Energy Co | 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 | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Assets, Fair Value Disclosure 0 0
Total liabilities 0 0
Baltimore Gas and Electric Company | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 1,006 205
Assets, Fair Value Disclosure 1,022 215
Total mark-to-market derivative liabilities 0 0
Deferred Compensation Liability, Current and Noncurrent (4) (4)
Total liabilities 4 4
Fair Value, Net Asset (Liability) 1,018 211
Baltimore Gas and Electric Company | Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:CashAndCashEquivalentsAtCarryingValue    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 8 15
Baltimore Gas and Electric Company | 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 10
Baltimore Gas and Electric Company | Fair Value, Recurring [Member] | Cash Equivalents [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0  
Baltimore Gas and Electric Company | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 16 10
Baltimore Gas and Electric Company | 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 | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 1,006 205
Assets, Fair Value Disclosure 1,022 215
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) 1,022 215
Baltimore Gas and Electric Company | 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 16 10
Baltimore Gas and Electric Company | 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  
Baltimore Gas and Electric Company | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 16 10
Baltimore Gas and Electric Company | 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 | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 0 0
Assets, Fair Value Disclosure 0 0
Total mark-to-market derivative liabilities 0 0
Deferred Compensation Liability, Current and Noncurrent (4) (4)
Total liabilities 4 4
Fair Value, Net Asset (Liability) (4) (4)
Baltimore Gas and Electric Company | 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 | 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  
Baltimore Gas and Electric Company | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0 0
Baltimore Gas and Electric Company | 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 | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 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 | 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 | 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  
Baltimore Gas and Electric Company | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0 0
Baltimore Gas and Electric Company | 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 | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Assets, Fair Value Disclosure 0 0
Total liabilities 0 0
Pepco Holdings LLC | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 34 83
Assets, Fair Value Disclosure 194 240
Deferred Compensation Liability, Current and Noncurrent (8) (9)
Total liabilities 8 9
Fair Value, Net Asset (Liability) 186 231
Pepco Holdings LLC | Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:CashAndCashEquivalentsAtCarryingValue    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 47 56
Pepco Holdings LLC | Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:RestrictedCash    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 2 2
Pepco Holdings LLC | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 160 157
Pepco Holdings LLC | Fair Value, Recurring [Member] | Cash Equivalents [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 103 99
Pepco Holdings LLC | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 9 9
Pepco Holdings LLC | Fair Value, Recurring [Member] | Fixed Income Investments [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 6 6
Pepco Holdings LLC | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 42 43
Pepco Holdings LLC | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 34 83
Assets, Fair Value Disclosure 146 191
Deferred Compensation Liability, Current and Noncurrent 0 0
Total liabilities 0 0
Fair Value, Net Asset (Liability) 146 191
Pepco Holdings LLC | 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 112 108
Pepco Holdings LLC | 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 103 99
Pepco Holdings LLC | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 9 9
Pepco Holdings LLC | 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 | 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 | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 0 0
Assets, Fair Value Disclosure 29 29
Deferred Compensation Liability, Current and Noncurrent (8) (9)
Total liabilities 8 9
Fair Value, Net Asset (Liability) 21 20
Pepco Holdings LLC | 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 29 29
Pepco Holdings LLC | 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 | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0 0
Pepco Holdings LLC | 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 6 6
Pepco Holdings LLC | 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 23 23
Pepco Holdings LLC | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 0 0
Assets, Fair Value Disclosure 19 20
Deferred Compensation Liability, Current and Noncurrent 0 0
Total liabilities 0 0
Fair Value, Net Asset (Liability) 19 20
Pepco Holdings LLC | 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 19 20
Pepco Holdings LLC | 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 | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 0 0
Pepco Holdings LLC | 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 | 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 19 20
Pepco Holdings LLC | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Assets, Fair Value Disclosure 0 0
Total liabilities 0 0
Potomac Electric Power Company | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 32 33
Assets, Fair Value Disclosure 176 174
Deferred Compensation Liability, Current and Noncurrent (1) (1)
Total liabilities 1 1
Fair Value, Net Asset (Liability) 175 173
Potomac Electric Power Company | Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:CashAndCashEquivalentsAtCarryingValue    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 20 22
Potomac Electric Power Company | Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 144 141
Potomac Electric Power Company | Fair Value, Recurring [Member] | Cash Equivalents [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 102 98
Potomac Electric Power Company | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Investments, Fair Value Disclosure 42 43
Potomac Electric Power Company | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 32 33
Assets, Fair Value Disclosure 134 131
Deferred Compensation Liability, Current and Noncurrent 0 0
Total liabilities 0 0
Fair Value, Net Asset (Liability) 134 131
Potomac Electric Power Company | 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 102 98
Potomac Electric Power Company | 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 102 98
Potomac Electric Power Company | 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 | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 0 0
Assets, Fair Value Disclosure 23 23
Deferred Compensation Liability, Current and Noncurrent (1) (1)
Total liabilities 1 1
Fair Value, Net Asset (Liability) 22 22
Potomac Electric Power Company | 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 23 23
Potomac Electric Power Company | 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 | 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 23 23
Potomac Electric Power Company | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 0 0
Assets, Fair Value Disclosure 19 20
Deferred Compensation Liability, Current and Noncurrent 0 0
Total liabilities 0 0
Fair Value, Net Asset (Liability) 19 20
Potomac Electric Power Company | 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 19 20
Potomac Electric Power Company | 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 | 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 19 20
Potomac Electric Power Company | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Assets, Fair Value Disclosure 0 0
Total liabilities 0 0
Delmarva Power and Light Company | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 2 3
Assets, Fair Value Disclosure 2 3
Deferred Compensation Liability, Current and Noncurrent 0 0
Total liabilities 0 0
Fair Value, Net Asset (Liability) 2 3
Delmarva Power and Light Company | Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:CashAndCashEquivalentsAtCarryingValue    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 8 9
Delmarva Power and Light Company | 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 and Light Company | 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 and Light Company | 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 and Light Company | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 2 3
Assets, Fair Value Disclosure 2 3
Deferred Compensation Liability, Current and Noncurrent 0 0
Total liabilities 0 0
Fair Value, Net Asset (Liability) 2 3
Delmarva Power and Light Company | 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 and Light Company | 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 and Light Company | 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 and Light Company | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 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 and Light Company | 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 and Light Company | 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 and Light Company | 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 and Light Company | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 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 and Light Company | 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 and Light Company | 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 and Light Company | 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
Delmarva Power and Light Company | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Assets, Fair Value Disclosure 0 0
Total liabilities 0 0
Atlantic City Electric Company | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 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 | Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:CashAndCashEquivalentsAtCarryingValue    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 13 22
Atlantic City Electric Company | Fair Value, Recurring [Member] | Balance Sheet Location [Axis]: us-gaap:RestrictedCash    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 2 2
Atlantic City Electric Company | 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 | 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 | 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 | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 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 | 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 | 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 | 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 | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 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 | 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 | 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 | 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 | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Cash equivalents 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 | 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 | 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 | 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 | Fair Value Measured at Net Asset Value Per Share [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]    
Assets, Fair Value Disclosure 0 0
Total liabilities $ 0 $ 0