Asset Retirement Obligations

12 Months Ended

Dec. 31, 2023

Asset Retirement Obligation Disclosure [Abstract]

The Company's AROs are primarily related to the environmental obligations for mine reclamation, ash disposal, site closures, fuel storage facilities and future dismantlement of equipment on leased property. In addition, the Company has also identified conditional AROs for asbestos removal and disposal, which are specific to certain power generation operations.

Following the sale of the Company's 44% equity interest in STP on November 1, 2023, the Company no longer has asset retirement obligations related to nuclear decommissioning. Prior to the sale, accretion for the nuclear decommissioning ARO and amortization of the related ARO asset were recorded to the Nuclear Decommissioning Trust Liability and were not included in net income, consistent with regulatory treatment per ASC 980, Regulated Operations.

The following table represents the balance of ARO obligations as of December 31, 2023 and 2022, along with the activity related to the Company's ARO obligations for the year ended December 31, 2023:


(In millions)	Nuclear Decommission		Other(a)		Total
Balance as of December 31, 2022	$	340	$	418	$	758
Revisions in estimates for current obligations	(13)		3		(10)
Additions	—		13		13
Spending for current obligations	—		(42)		(42)
Accretion	16		23		39
Dispositions	(343)		(8)		(351)
Balance as of December 31, 2023	$	—	$	407	$	407

(a)Total accretion expense related to asset retirement obligations included in the consolidated statement of cash flows includes accretion and revisions in estimates for asset retirement liabilities on non-operating plants