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
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]
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