Asset Retirement Obligation (Notes)

12 Months Ended

Dec. 31, 2023

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligation Disclosure [Text Block]

ASSET RETIREMENT OBLIGATIONS

The following table presents amounts recognized related to asset retirement obligations for the periods indicated (in millions):

	2023		2022
Balance at January 1	$	757	$	606
Additional liabilities incurred	40		97
Liabilities assumed in acquisition	—		15
Liabilities settled	(14)		(29)
Accretion expense	31		30
Change in estimated cash flows	(35)		35
Other	(1)		3
Balance at December 31	$	778	$	757

The Company's asset retirement obligations include active ash landfills, water treatment basins, and the removal or dismantlement of certain plants and equipment. The Company uses the cost approach to determine the initial value of ARO liabilities, which is estimated by discounting expected cash outflows to their present value using market-based rates at the initial recording of the liabilities. Cash outflows are based on the approximate future disposal costs as determined by market information, historical information or other management estimates. Subsequent downward revisions of ARO liabilities are discounted using the market-based rates that existed when the liability was initially recognized. These inputs to the fair value of the ARO liabilities are considered Level 3 inputs under the fair value hierarchy.

During the year ended December 31, 2023, the Company increased the asset retirement obligations and corresponding assets at AES Clean Energy and AES Indiana by $43 million and $34 million, respectively. This was offset by decreases at Southland Energy and AES Brasil of $51 million and $20 million, respectively. The increase at AES Clean Energy is mostly due to an upward revision of estimated cash flows as a result of a decommissioning study done in the fourth quarter of 2023, which mostly impacted the estimated cash flows related to solar assets.

The increase at AES Indiana is mostly due to additional liabilities incurred due to revised remediation plans for ash ponds at Eagle Valley and AES Indiana's solar projects. The decrease at Southland Energy is mostly due to a downward revision of estimated cash flows as a result of revised quotes from vendors for the demolition of the Southland legacy units. The decrease at AES Brasil is mostly due to a downward revision of estimated cash flows at the Mandacaru, Salinas, and Cubico II wind complexes and AES Brasil solar facilities.

During the year ended December 31, 2022, the Company increased the asset retirement obligations and corresponding assets at Southland Energy, AES Clean Energy, AES Indiana, and AES Brasil by $75 million, $27 million, $27 million, and $16 million, respectively. The increase at Southland Energy is mostly due to additional liabilities incurred related to a demolition obligation at Alamitos. The increase at AES Clean Energy is mostly due to additional liabilities incurred as a result of new development projects. The increase at AES Indiana is primarily due to an upward revision of estimated cash flows at the Petersburg, Eagle Valley, and Harding Street plants. The increase at AES Brasil is primarily due to the initial recognition of asset retirement obligations as a result of the Cubico II acquisition.