Early Plant Retirements (Tables)

3 Months Ended

Mar. 31, 2021

Property, Plant and Equipment [Abstract]

Restructuring and Related Costs [Table Text Block]

As a result of the decision to early retire Byron and Dresden, Exelon and Generation recognized certain one-time charges in the third and fourth quarters of 2020 related to materials and supplies inventory reserve adjustments, employee-related costs including severance benefit costs further discussed below, and construction work-in-progress impairments, among other items. In addition, as a result of the decisions to early retire Byron and Dresden, there are ongoing annual financial impacts stemming from shortening the expected economic useful lives of these nuclear plants primarily related to accelerated depreciation of plant assets (including any ARC), accelerated amortization of nuclear fuel, and changes in ARO accretion expense associated with the changes in decommissioning timing and cost assumptions to reflect an earlier retirement date. The total impact for the three months ended March 31, 2021 on Exelon's and Generation's Consolidated Statements of Operations and Comprehensive Income is summarized in the table below.

Income statement expense (pre-tax)	Three Months Ended March 31, 2021(a)
Depreciation and amortization
Accelerated depreciation(a)	$	620
Accelerated nuclear fuel amortization	54
Operating and maintenance
Other charges	2
Contractual offset(b)	(226)
Total	$	450

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(a)Includes the accelerated depreciation of plant assets including any ARC.

(b)Reflects contractual offset for ARO accretion and ARC depreciation. Based on the regulatory agreement with the ICC, decommissioning-related activities in the first quarter of 2021 have been offset within Exelon's and Generation's Consolidated Statements of Operations and Comprehensive Income. The offset in 2021 resulted in an equal adjustment to the noncurrent payables to ComEd at Generation and an adjustment to the regulatory liabilities at ComEd. See Note 10 - Asset Retirement Obligations of the Exelon 2020 Form 10-K for additional information.

Implications of Potential Early Plant Retirement on Balance Sheet [Table Text Block]

The following table provides the balance sheet amounts as of March 31, 2021 for Exelon's and Generation's significant assets and liabilities associated with the Braidwood and LaSalle nuclear plants. Current depreciation provisions are based on the estimated useful lives of these nuclear generating stations, which reflect the first renewal of the operating licenses.

	Braidwood		LaSalle		Total
Asset Balances
Materials and supplies inventory, net	$	83	$	103	$	186
Nuclear fuel inventory, net	165		264		429
Completed plant, net	1,379		1,566		2,945
Construction work in progress	33		70		103
Liability Balances
Asset retirement obligation	(577)		(964)		(1,541)
NRC License First Renewal Term	2046 (Unit 1)		2042 (Unit 1)
	2047 (Unit 2)		2043 (Unit 2)