Supplemental Financial Information - Cash Flow (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Depreciation, Amortization and Accretion [Abstract]
Property, plant and equipment			$ 1,370	$ 1,376
Amortization of regulatory assets			352	357
Amortization of intangible assets, net			4	8
Amortization of energy contract assets and liabilities				3
Nuclear fuel				66
ARO accretion			1	44
Depreciation, Amortization and Accretion, Net			1,727	1,854
Other Non-Cash Operating Activities [Abstract]
Pension and non-pension postretirement benefit costs			89	86
Allowance for credit losses			46	96
Other decommissioning-related activity				36
Energy-related options				60
True-up adjustments to decoupling mechanisms and formula rates	$ 126	$ (2)	404	27
Long-term incentive plan			13	40
Amortization of operating ROU asset			19	38
Change in environmental liabilities			37
AFUDC - Equity	(34)	(38)	(71)	(74)
Other Non-Cash Activity
Other Non-Cash Operating Activities [Abstract]
True-up adjustments to decoupling mechanisms and formula rates			(410)	(27)
Return on borrowed funds
Other Non-Cash Operating Activities [Abstract]
AFUDC - Equity			(71)	(74)
Commonwealth Edison Co [Member]
Depreciation, Amortization and Accretion [Abstract]
Property, plant and equipment			540	511
Amortization of regulatory assets			148	138
Amortization of intangible assets, net			0	0
Amortization of energy contract assets and liabilities				0
Nuclear fuel				0
ARO accretion			0	0
Depreciation, Amortization and Accretion, Net			688	649
Other Non-Cash Operating Activities [Abstract]
Pension and non-pension postretirement benefit costs			13	30
Allowance for credit losses			1	29
Other decommissioning-related activity				0
Energy-related options				0
True-up adjustments to decoupling mechanisms and formula rates	118	35	270	75
Long-term incentive plan			0	0
Amortization of operating ROU asset			1	1
Change in environmental liabilities			0
AFUDC - Equity	(7)	(9)	(17)	(17)
Commonwealth Edison Co [Member] | Other Non-Cash Activity
Other Non-Cash Operating Activities [Abstract]
True-up adjustments to decoupling mechanisms and formula rates			(270)	(75)
Commonwealth Edison Co [Member] | Return on borrowed funds
Other Non-Cash Operating Activities [Abstract]
AFUDC - Equity			(17)	(17)
PECO Energy Co [Member]
Depreciation, Amortization and Accretion [Abstract]
Property, plant and equipment			190	177
Amortization of regulatory assets			7	8
Amortization of intangible assets, net			0	0
Amortization of energy contract assets and liabilities				0
Nuclear fuel				0
ARO accretion			0	0
Depreciation, Amortization and Accretion, Net			197	185
Other Non-Cash Operating Activities [Abstract]
Pension and non-pension postretirement benefit costs			(7)	(4)
Allowance for credit losses			19	21
Other decommissioning-related activity				0
Energy-related options				0
True-up adjustments to decoupling mechanisms and formula rates	(5)	0	(10)	6
Long-term incentive plan			0	0
Amortization of operating ROU asset			0	0
Change in environmental liabilities			0
AFUDC - Equity	(6)	(8)	(12)	(15)
PECO Energy Co [Member] | Other Non-Cash Activity
Other Non-Cash Operating Activities [Abstract]
True-up adjustments to decoupling mechanisms and formula rates			10	(6)
PECO Energy Co [Member] | Return on borrowed funds
Other Non-Cash Operating Activities [Abstract]
AFUDC - Equity			(12)	(15)
Baltimore Gas and Electric Company [Member]
Depreciation, Amortization and Accretion [Abstract]
Property, plant and equipment			249	235
Amortization of regulatory assets			76	87
Amortization of intangible assets, net			0	0
Amortization of energy contract assets and liabilities				0
Nuclear fuel				0
ARO accretion			0	0
Depreciation, Amortization and Accretion, Net			325	322
Other Non-Cash Operating Activities [Abstract]
Pension and non-pension postretirement benefit costs			28	22
Allowance for credit losses			4	18
Other decommissioning-related activity				0
Energy-related options				0
True-up adjustments to decoupling mechanisms and formula rates	4	(20)	70	(32)
Long-term incentive plan			0	0
Amortization of operating ROU asset			2	14
Change in environmental liabilities			0
AFUDC - Equity	(4)	(6)	(7)	(12)
Baltimore Gas and Electric Company [Member] | Other Non-Cash Activity
Other Non-Cash Operating Activities [Abstract]
True-up adjustments to decoupling mechanisms and formula rates			(70)	32
Baltimore Gas and Electric Company [Member] | Return on borrowed funds
Other Non-Cash Operating Activities [Abstract]
AFUDC - Equity			(7)	(12)
Pepco Holdings LLC [Member]
Depreciation, Amortization and Accretion [Abstract]
Property, plant and equipment			364	335
Amortization of regulatory assets			120	124
Amortization of intangible assets, net			0	0
Amortization of energy contract assets and liabilities				0
Nuclear fuel				0
ARO accretion			0	0
Depreciation, Amortization and Accretion, Net			484	459
Other Non-Cash Operating Activities [Abstract]
Pension and non-pension postretirement benefit costs			49	26
Allowance for credit losses			22	29
Other decommissioning-related activity				0
Energy-related options				0
True-up adjustments to decoupling mechanisms and formula rates	9	(17)	74	(22)
Long-term incentive plan			0	0
Amortization of operating ROU asset			14	14
Change in environmental liabilities			37
AFUDC - Equity	(17)	(15)	(35)	(30)
Pepco Holdings LLC [Member] | Other Non-Cash Activity
Other Non-Cash Operating Activities [Abstract]
True-up adjustments to decoupling mechanisms and formula rates			(80)	22
Pepco Holdings LLC [Member] | Return on borrowed funds
Other Non-Cash Operating Activities [Abstract]
AFUDC - Equity			(35)	(30)
Potomac Electric Power Company [Member]
Depreciation, Amortization and Accretion [Abstract]
Property, plant and equipment			152	145
Amortization of regulatory assets			64	68
Amortization of intangible assets, net			0	0
Amortization of energy contract assets and liabilities				0
Nuclear fuel				0
ARO accretion			0	0
Depreciation, Amortization and Accretion, Net			216	213
Other Non-Cash Operating Activities [Abstract]
Pension and non-pension postretirement benefit costs			17	4
Allowance for credit losses			13	16
Other decommissioning-related activity				0
Energy-related options				0
True-up adjustments to decoupling mechanisms and formula rates	7	(1)	46	(7)
Long-term incentive plan			0	0
Amortization of operating ROU asset			2	4
Change in environmental liabilities			37
AFUDC - Equity	(13)	(11)	(27)	(22)
Potomac Electric Power Company [Member] | Other Non-Cash Activity
Other Non-Cash Operating Activities [Abstract]
True-up adjustments to decoupling mechanisms and formula rates			(46)	7
Potomac Electric Power Company [Member] | Return on borrowed funds
Other Non-Cash Operating Activities [Abstract]
AFUDC - Equity			(27)	(22)
Delmarva Power and Light Company [Member]
Depreciation, Amortization and Accretion [Abstract]
Property, plant and equipment			104	92
Amortization of regulatory assets			17	21
Amortization of intangible assets, net			0	0
Amortization of energy contract assets and liabilities				0
Nuclear fuel				0
ARO accretion			0	0
Depreciation, Amortization and Accretion, Net			121	113
Other Non-Cash Operating Activities [Abstract]
Pension and non-pension postretirement benefit costs			9	2
Allowance for credit losses			3	6
Other decommissioning-related activity				0
Energy-related options				0
True-up adjustments to decoupling mechanisms and formula rates	3	(2)	12	(3)
Long-term incentive plan			0	0
Amortization of operating ROU asset			4	4
Change in environmental liabilities			0
AFUDC - Equity	(2)	(2)	(4)	(4)
Delmarva Power and Light Company [Member] | Other Non-Cash Activity
Other Non-Cash Operating Activities [Abstract]
True-up adjustments to decoupling mechanisms and formula rates			(15)	3
Delmarva Power and Light Company [Member] | Return on borrowed funds
Other Non-Cash Operating Activities [Abstract]
AFUDC - Equity			(4)	(4)
Atlantic City Electric Company [Member]
Depreciation, Amortization and Accretion [Abstract]
Property, plant and equipment			96	83
Amortization of regulatory assets			39	35
Amortization of intangible assets, net			0	0
Amortization of energy contract assets and liabilities				0
Nuclear fuel				0
ARO accretion			0	0
Depreciation, Amortization and Accretion, Net			135	118
Other Non-Cash Operating Activities [Abstract]
Pension and non-pension postretirement benefit costs			7	6
Allowance for credit losses			6	7
Other decommissioning-related activity				0
Energy-related options				0
True-up adjustments to decoupling mechanisms and formula rates	(1)	(15)	16	(12)
Long-term incentive plan			0	0
Amortization of operating ROU asset			2	2
Change in environmental liabilities			0
AFUDC - Equity	$ (2)	$ (2)	(4)	(4)
Atlantic City Electric Company [Member] | Other Non-Cash Activity
Other Non-Cash Operating Activities [Abstract]
True-up adjustments to decoupling mechanisms and formula rates			(19)	12
Atlantic City Electric Company [Member] | Return on borrowed funds
Other Non-Cash Operating Activities [Abstract]
AFUDC - Equity			$ (4)	$ (4)