Fair Value of Financial Assets and Liabilities - Fair Value Measurements of Assets and Liabilities, Recurring and Nonrecurring (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Mark-to-market derivative liabilities (current liabilities)	$ 44	$ 8
Derivative Liability, Noncurrent	113	83
Fair Value, Recurring [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents	649	664
Assets, Fair Value Disclosure	921	891
Deferred Compensation Liability, Current and Noncurrent	(69)	(75)
Total liabilities	226	166
Fair Value, Net Asset (Liability)	695	725
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	(134)	(84)
Fair Value, Recurring [Member] | Derivatives Designated as Hedging Instruments Liabilities
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Total mark-to-market derivative liabilities	0	(4)
Fair Value, Recurring [Member] | Economic Hedging Instrument Liabilites [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Total mark-to-market derivative liabilities	(23)	(3)
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	(23)	(7)
Fair Value, Recurring [Member] | Cash and Cash Equivalents [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents	188	345
Fair Value, Recurring [Member] | Restricted cash member [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents	110	81
Fair Value, Recurring [Member] | Other Assets [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents	212	117
Fair Value, Recurring [Member] | Rabbi Trust Investments [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, Fair Value Disclosure	228	216
Fair Value, Recurring [Member] | Cash Equivalents [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, Fair Value Disclosure	66	62
Fair Value, Recurring [Member] | Mutual Funds [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, Fair Value Disclosure	53	49
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	102	98
Fair Value, Recurring [Member] | Designated as Hedging Instrument [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Derivative Asset	41	6
Fair Value, Recurring [Member] | Economic Hedges
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Derivative Asset	3	5
Fair Value, Recurring [Member] | Interest Rate Derivative Assets
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Derivative Asset	44	11
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents	649	664
Assets, Fair Value Disclosure	768	775
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	0	0
Fair Value, Net Asset (Liability)	768	775
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	119	111
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	66	62
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	53	49
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | 6311 Life Insurance [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Designated as Hedging Instrument [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Derivative Asset	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]
Derivative Asset	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]
Derivative Asset	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	111	76
Deferred Compensation Liability, Current and Noncurrent	(69)	(75)
Total liabilities	92	82
Fair Value, Net Asset (Liability)	19	(6)
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mark-to-Market Derivative Liabilities
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Total mark-to-market derivative liabilities	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Derivatives Designated as Hedging Instruments Liabilities
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Total mark-to-market derivative liabilities	0	(4)
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Economic Hedging Instrument Liabilites [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Total mark-to-market derivative liabilities	(23)	(3)
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	(23)	(7)
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	67	65
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	60	58
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Designated as Hedging Instrument [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Derivative Asset	41	6
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Economic Hedges
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Derivative Asset	3	5
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]
Derivative Asset	44	11
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	42	40
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	134	84
Fair Value, Net Asset (Liability)	(92)	(44)
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	(134)	(84)
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	42	40
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	42	40
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Designated as Hedging Instrument [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Derivative Asset	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]
Derivative Asset	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]
Derivative Asset	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)	21	5
Derivative Liability, Noncurrent	113	79
Commonwealth Edison Co | Fair Value, Recurring [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents	491	392
Assets, Fair Value Disclosure	491	392
Total mark-to-market derivative liabilities	(134)	(84)
Deferred Compensation Liability, Current and Noncurrent	(7)	(8)
Total liabilities	141	92
Fair Value, Net Asset (Liability)	350	300
Mark-to-market derivative liabilities (current liabilities)	(21)	5	$ 0
Derivative Liability, Noncurrent	(113)	79	$ (67)
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	55	42
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	105	77
Commonwealth Edison Co | Fair Value, Recurring [Member] | Other Assets [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Cash equivalents	212	117
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	491	392
Assets, Fair Value Disclosure	491	392
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)	491	392
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	(7)	(8)
Total liabilities	7	8
Fair Value, Net Asset (Liability)	(7)	(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	(134)	(84)
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	134	84
Fair Value, Net Asset (Liability)	(134)	(84)
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	29	10
Assets, Fair Value Disclosure	55	32
Total mark-to-market derivative liabilities	0	0
Deferred Compensation Liability, Current and Noncurrent	(8)	(7)
Total liabilities	8	7
Fair Value, Net Asset (Liability)	47	25
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	23	58
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	26	22
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	9	7
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	17	15
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	29	10
Assets, Fair Value Disclosure	38	17
Total mark-to-market derivative liabilities	0	0
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	0	0
Fair Value, Net Asset (Liability)	38	17
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	9	7
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	9	7
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	17	15
Total mark-to-market derivative liabilities	0	0
Deferred Compensation Liability, Current and Noncurrent	(8)	(7)
Total liabilities	8	7
Fair Value, Net Asset (Liability)	9	8
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	17	15
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	17	15
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	2	23
Assets, Fair Value Disclosure	11	30
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)	7	26
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	13	43
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	1	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	9	7
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	9	7
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	2	23
Assets, Fair Value Disclosure	11	30
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)	11	30
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	9	7
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	9	7
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	83	205
Assets, Fair Value Disclosure	224	343
Deferred Compensation Liability, Current and Noncurrent	(13)	(14)
Total liabilities	13	14
Fair Value, Net Asset (Liability)	211	329
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	60	165
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	3	3
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	141	138
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	63	59
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	10	11
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	61	61
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	83	205
Assets, Fair Value Disclosure	156	275
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	0	0
Fair Value, Net Asset (Liability)	156	275
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	73	70
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	63	59
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	10	11
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	28	29
Deferred Compensation Liability, Current and Noncurrent	(13)	(14)
Total liabilities	13	14
Fair Value, Net Asset (Liability)	15	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	28	29
Pepco Holdings LLC | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Cash Equivalents [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, Fair Value Disclosure	0	0
Pepco Holdings LLC | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mutual Funds [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, Fair Value Disclosure	0	0
Pepco Holdings LLC | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Fixed Income Investments [Member]
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Investments, Fair Value Disclosure	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	21	22
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	40	39
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	0	0
Fair Value, Net Asset (Liability)	40	39
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	40	39
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	40	39
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	22	51
Assets, Fair Value Disclosure	145	170
Deferred Compensation Liability, Current and Noncurrent	(1)	(1)
Total liabilities	1	1
Fair Value, Net Asset (Liability)	144	169
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	31	45
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	3	3
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	123	119
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	62	59
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	61	60
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	22	51
Assets, Fair Value Disclosure	84	110
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	0	0
Fair Value, Net Asset (Liability)	84	110
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	62	59
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	62	59
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	21	22
Deferred Compensation Liability, Current and Noncurrent	(1)	(1)
Total liabilities	1	1
Fair Value, Net Asset (Liability)	20	21
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	21	22
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	21	22
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	40	38
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	0	0
Fair Value, Net Asset (Liability)	40	38
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	40	38
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	40	38
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	1	121
Assets, Fair Value Disclosure	1	121
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	0	0
Fair Value, Net Asset (Liability)	1	121
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	5	31
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	1	121
Assets, Fair Value Disclosure	1	121
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	0	0
Fair Value, Net Asset (Liability)	1	121
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	1	1
Assets, Fair Value Disclosure	1	1
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	0	0
Fair Value, Net Asset (Liability)	1	1
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	13	71
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	1	1
Assets, Fair Value Disclosure	1	1
Deferred Compensation Liability, Current and Noncurrent	0	0
Total liabilities	0	0
Fair Value, Net Asset (Liability)	1	1
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