Early Plant Retirements (Tables)

6 Months Ended

Jun. 30, 2019

Property, Plant and Equipment [Abstract]

Income statement expense (pre-tax)

As a result of these early nuclear plant retirement decisions, Exelon and Generation recognized incremental non-cash charges to earnings stemming from shortening the expected economic useful lives primarily related to accelerated depreciation of plant assets (including any ARC) and accelerated amortization of nuclear fuel, as well as operating and maintenance expenses. See Note 13 — Nuclear Decommissioning for additional information on changes to the nuclear decommissioning ARO balance. The total impact for the three and six months ended June 30, 2019 and 2018 are summarized in the table below.

	Three Months Ended June 30,				Six Months Ended June 30,
Income statement expense (pre-tax)	2019		2018		2019			2018
Depreciation and amortization(a)
Accelerated depreciation	$	71	$	152	$	145		$	289
Accelerated nuclear fuel amortization	4		19		9			34
Operating and maintenance(b)	—		2		(83		)	28
Total	$	75	$	173	$	71		$	351

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(a) Reflects incremental accelerated depreciation and amortization for TMI for the three and six months ended June 30, 2019. Reflects incremental accelerated depreciation for TMI and Oyster Creek for the three and six months ended June 30, 2018. The Oyster Creek amounts are from February 2, 2018 through June 30, 2018.

(b) In 2019, primarily reflects decrease to estimated decommissioning costs for TMI. See Note 13 — Nuclear Decommissioning for additional information on the first quarter 2019 TMI ARO update. In 2018, primarily reflects materials and supplies inventory reserve adjustments, employee related costs and CWIP impairments associated with the early retirement decisions for TMI and Oyster Creek.

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

The following table provides the balance sheet amounts as of June 30, 2019 for Exelon's and Generation’s significant assets and liabilities associated with the Mystic Units 8 and 9 and Everett Marine Terminal assets that would potentially be impacted by a decision to permanently cease generation operations in the absence of long-term market rule changes.

	June 30, 2019
Asset Balances
Materials and supplies inventory	$	30
Fuel inventory	11
Completed plant, net	896
Construction work in progress	4
Liability Balances
Asset retirement obligation	(1		)