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Fair Value of Financial Assets and Liabilities - Fair Value Measurements of Assets and Liabilities, Recurring and Nonrecurring (Details) - USD ($) $ in Millions | Sep. 30, 2024 | Dec. 31, 2023
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Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Mark-to-market derivative liabilities (current liabilities) | $ 25 | $ 74
Mark-to-market derivative liabilities (noncurrent liabilities) | 180 | 106
Fair Value, Recurring [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 861 | 618
Assets, Fair Value Disclosure | 1,115 | 861
Deferred Compensation Liability, Current and Noncurrent | (75) | (75)
Total liabilities | 279 | 254
Fair Value, Net Asset (Liability) | 836 | 607
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 | (165) | (133)
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 | (39) | (24)
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 | (22)
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 | (39) | (46)
Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 205 | 334
Fair Value, Recurring [Member] | Restricted cash member [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 167 | 149
Fair Value, Recurring [Member] | Other Assets [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 65 | 174
Fair Value, Recurring [Member] | Rabbi Trust Investments [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Investments, Fair Value Disclosure | 254 | 231
Fair Value, Recurring [Member] | Cash Equivalents [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Investments, Fair Value Disclosure | 93 | 67
Fair Value, Recurring [Member] | Mutual Funds [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Investments, Fair Value Disclosure | 62 | 53
Fair Value, Recurring [Member] | Fixed Income Investments [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Investments, Fair Value Disclosure | 7 | 7
Fair Value, Recurring [Member] | 6311 Life Insurance [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Investments, Fair Value Disclosure | 92 | 104
Fair Value, Recurring [Member] | Derivatives Designated as Hedging Instruments |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Total derivative assets | 0 | 11
Fair Value, Recurring [Member] | Economic Hedges |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Total derivative assets | 0 | 1
Fair Value, Recurring [Member] | Interest Rate Derivative Assets |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Total derivative assets | 0 | 12
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 861 | 618
Assets, Fair Value Disclosure | 1,016 | 738
Deferred Compensation Liability, Current and Noncurrent | 0 | 0
Total liabilities | 0 | 0
Fair Value, Net Asset (Liability) | 1,016 | 738
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] | 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] | 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 | 155 | 120
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 | 93 | 67
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 | 62 | 53
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] | Derivatives Designated as Hedging Instruments |  |
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] | Economic Hedges |  |
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 | 77 | 80
Deferred Compensation Liability, Current and Noncurrent | (75) | (75)
Total liabilities | 114 | 121
Fair Value, Net Asset (Liability) | (37) | (41)
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 | (39) | (24)
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 | (22)
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 | (39) | (46)
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 | 77 | 68
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 | 7 | 7
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 | 70 | 61
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Derivatives Designated as Hedging Instruments |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Total derivative assets | 0 | 11
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Economic Hedges |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Total derivative assets | 0 | 1
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 | 0 | 12
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 | 22 | 43
Deferred Compensation Liability, Current and Noncurrent | 0 | 0
Total liabilities | 165 | 133
Fair Value, Net Asset (Liability) | (143) | (90)
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 | (165) | (133)
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] | 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 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 | 22 | 43
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 | 22 | 43
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Derivatives Designated as Hedging Instruments |  |
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] | Economic Hedges |  |
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 (current liabilities) | 25 | 27
Mark-to-market derivative liabilities (noncurrent liabilities) | 140 | 106
Commonwealth Edison Co | Fair Value, Recurring [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 403 | 453
Assets, Fair Value Disclosure | 403 | 453
Total mark-to-market derivative liabilities | (165) | (133)
Deferred Compensation Liability, Current and Noncurrent | (9) | (8)
Total liabilities | 174 | 141
Fair Value, Net Asset (Liability) | 229 | 312
Mark-to-market derivative liabilities (current liabilities) | 25 | 27
Mark-to-market derivative liabilities (noncurrent liabilities) | 140 | 106
Commonwealth Edison Co | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 84 | 86
Commonwealth Edison Co | Fair Value, Recurring [Member] | Restricted cash member [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 167 | 147
Commonwealth Edison Co | Fair Value, Recurring [Member] | Other Assets [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 65 | 174
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] | 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 | 403 | 453
Assets, Fair Value Disclosure | 403 | 453
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) | 403 | 453
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] | 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) | (8)
Total liabilities | 9 | 8
Fair Value, Net Asset (Liability) | (9) | (8)
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] | 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 | (165) | (133)
Deferred Compensation Liability, Current and Noncurrent | 0 | 0
Total liabilities | 165 | 133
Fair Value, Net Asset (Liability) | (165) | (133)
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] | 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 | 18 | 9
Assets, Fair Value Disclosure | 50 | 36
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) | 43 | 28
PECO Energy Co | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 19 | 42
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 | 32 | 27
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 | 11 | 9
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 | 21 | 18
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 | 18 | 9
Assets, Fair Value Disclosure | 29 | 18
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) | 29 | 18
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 | 11 | 9
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 | 11 | 9
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 | 21 | 18
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) | 14 | 10
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 | 21 | 18
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 | 21 | 18
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] | 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 | 313 | 0
Assets, Fair Value Disclosure | 323 | 9
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) | 319 | 5
Baltimore Gas and Electric Company | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 18 | 47
Baltimore Gas and Electric Company | Fair Value, Recurring [Member] | Restricted cash member [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 0 | 1
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 | 10 | 9
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 | 10 | 9
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 | 313 | 0
Assets, Fair Value Disclosure | 323 | 9
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) | 323 | 9
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 | 10 | 9
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 | 10 | 9
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] | 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] | 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 | 74 | 107
Assets, Fair Value Disclosure | 224 | 249
Deferred Compensation Liability, Current and Noncurrent | (11) | (13)
Total liabilities | 11 | 13
Fair Value, Net Asset (Liability) | 213 | 236
Pepco Holdings LLC | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 48 | 96
Pepco Holdings LLC | Fair Value, Recurring [Member] | Restricted cash member [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 0 | 1
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 | 150 | 142
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 | 90 | 64
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 | 7 | 7
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 | 44 | 62
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 | 74 | 107
Assets, Fair Value Disclosure | 173 | 180
Deferred Compensation Liability, Current and Noncurrent | 0 | 0
Total liabilities | 0 | 0
Fair Value, Net Asset (Liability) | 173 | 180
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 | 99 | 73
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 | 90 | 64
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 | 30 | 28
Deferred Compensation Liability, Current and Noncurrent | (11) | (13)
Total liabilities | 11 | 13
Fair Value, Net Asset (Liability) | 19 | 15
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 | 30 | 28
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 | 7 | 7
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 | 21
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 | 21 | 41
Deferred Compensation Liability, Current and Noncurrent | 0 | 0
Total liabilities | 0 | 0
Fair Value, Net Asset (Liability) | 21 | 41
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 | 21 | 41
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 | 21 | 41
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 | 21 | 23
Assets, Fair Value Disclosure | 155 | 148
Deferred Compensation Liability, Current and Noncurrent | (1) | (1)
Total liabilities | 1 | 1
Fair Value, Net Asset (Liability) | 154 | 147
Potomac Electric Power Company | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 19 | 48
Potomac Electric Power Company | Fair Value, Recurring [Member] | Restricted cash member [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 0 | 1
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 | 134 | 125
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 | 90 | 63
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 | 44 | 62
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 | 21 | 23
Assets, Fair Value Disclosure | 111 | 86
Deferred Compensation Liability, Current and Noncurrent | 0 | 0
Total liabilities | 0 | 0
Fair Value, Net Asset (Liability) | 111 | 86
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 | 90 | 63
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 | 90 | 63
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 | 21
Deferred Compensation Liability, Current and Noncurrent | (1) | (1)
Total liabilities | 1 | 1
Fair Value, Net Asset (Liability) | 22 | 20
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 | 21
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 | 21
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 | 21 | 41
Deferred Compensation Liability, Current and Noncurrent | 0 | 0
Total liabilities | 0 | 0
Fair Value, Net Asset (Liability) | 21 | 41
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 | 21 | 41
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 | 21 | 41
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 | 3 | 1
Assets, Fair Value Disclosure | 3 | 1
Deferred Compensation Liability, Current and Noncurrent | 0 | 0
Total liabilities | 0 | 0
Fair Value, Net Asset (Liability) | 3 | 1
Delmarva Power and Light Company | Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 7 | 15
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 | 3 | 1
Assets, Fair Value Disclosure | 3 | 1
Deferred Compensation Liability, Current and Noncurrent | 0 | 0
Total liabilities | 0 | 0
Fair Value, Net Asset (Liability) | 3 | 1
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] | Cash and Cash Equivalents [Member] |  |
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract] |  |
Cash equivalents | 17 | 21
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] |  |
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