Revenue from Contracts with Customers (Tables)

3 Months Ended

Mar. 31, 2021

Contracts with Customers [Line Items]

Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]

The following table shows the amounts of future revenues expected to be recorded in each year for performance obligations that are unsatisfied or partially unsatisfied as of March 31, 2021. This disclosure only includes contracts for which the total consideration is fixed and determinable at contract inception. The average contract term varies by customer type and commodity but ranges from one month to several years.

This disclosure excludes Generation's power and gas sales contracts as they contain variable volumes and/or variable pricing. This disclosure also excludes the Utility Registrants' gas and electric tariff sales contracts and transmission revenue contracts as they generally have an original expected duration of one year or less and, therefore, do not contain any future, unsatisfied performance obligations to be included in this disclosure.

	2021		2022		2023		2024		2025 and thereafter		Total
Exelon	$	233	$	100	$	56	$	41	$	330	$	760
Generation	286		131		56		35		243		751
PHI	7		8		8		6		87		116
Pepco	5		6		6		5		70		92
DPL	1		1		1		—		9		12
ACE	1		1		1		1		8		12

Contract Assets [Member]

Contracts with Customers [Line Items]

Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block]

The following table provides a rollforward of the contract assets reflected in Exelon's and Generation's Consolidated Balance Sheets for the three months ended March 31, 2021 and 2020. The Utility Registrants do not have any contract assets.

	Exelon		Generation
Balance as of December 31, 2020	$	144	$	144
Amounts reclassified to receivables	(16)		(16)
Revenues recognized	13		13
Amounts previously held-for-sale	12		12
Balance as of March 31, 2021	$	153	$	153
	Exelon		Generation
Balance as of December 31, 2019	$	174	$	174
Amounts reclassified to receivables	(19)		(19)
Revenues recognized	17		17
Balance as of March 31, 2020	$	172	$	172

Contract Liabilities [Member]

Contracts with Customers [Line Items]

Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block]

The following table provides a rollforward of the contract liabilities reflected in Exelon's, Generation's, PHI's, Pepco's, DPL's, and ACE's Consolidated Balance Sheets for the three months ended March 31, 2021 and 2020. As of March 31, 2021 and December 31, 2020, ComEd's, PECO's, and BGE's contract liabilities were immaterial.

	Exelon		Generation		PHI		Pepco		DPL		ACE
Balance as of December 31, 2020	$	151	$	84	$	118	$	94	$	12	$	12
Consideration received or due	20		31		—		—		—		—
Revenues recognized	(27)		(64)		(2)		(2)		—		—
Amounts previously held-for-sale	3		3		—		—		—		—
Balance as of March 31, 2021	$	147	$	54	$	116	$	92	$	12	$	12
	Exelon		Generation		PHI		Pepco		DPL		ACE
Balance as of December 31, 2019	$	33	$	71	$	—	$	—	$	—	$	—
Consideration received or due	20		55		—		—		—		—
Revenues recognized	(24)		(70)		—		—		—		—
Balance as of March 31, 2020	$	29	$	56	$	—	$	—	$	—	$	—

The following table reflects revenues recognized in the three months ended March 31, 2021 and 2020, which were included in contract liabilities at December 31, 2020 and 2019, respectively:

	Three Months Ended March 31,
	2021		2020
Exelon	$	17	$	9
Generation	39		19
PHI	2		—
Pepco	2		—