Revenue from Contracts with Customers (Tables)

3 Months Ended

Mar. 31, 2019

Revenue from Contract with Customer [Abstract]

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

The following table provides a rollforward of the contract assets and liabilities reflected in Exelon's and Generation's Consolidated Balance Sheets from January 1, 2018 to March 31, 2019:

	Contract Assets						Contract Liabilities
	Exelon			Generation			Exelon			Generation
Balance as of January 1, 2018	$	283		$	283		$	35		$	35
Increases as a result of changes in the estimate of the stage of completion	50			50			—			—
Increases as a result of additional cash received or due	—			—			179			465
Amounts reclassified into receivables or recognized into revenues	(146		)	(146		)	(187		)	(458		)
Balance at December 31, 2018	187			187			27			42
Increases as a result of changes in the estimate of the stage of completion	26			26			—			—
Increases as a result of additional cash received or due	—			—			21			63
Amounts reclassified into receivables or recognized into revenues	(26		)	(26		)	(23		)	(66		)
Balance at March 31, 2019	$	187		$	187		$	25		$	39

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

	2019		2020		2021		2022		2023 and thereafter		Total
Exelon	$	393	$	273	$	112	$	50	$	142	$	970
Generation	493		331		126		50		142		1,142