Alcoa Corporation has recorded AROs related to legal obligations associated with the standard operation of bauxite mines, alumina refineries, and aluminum smelters. These AROs consist primarily of costs associated with mine reclamation, closure of bauxite residue areas, spent pot lining disposal, and landfill closure. Alcoa Corporation also recognizes AROs for any significant lease restoration obligation, if required by a lease agreement, and for the disposal of regulated waste materials related to the demolition of certain power facilities.

In addition to AROs, certain CAROs related to alumina refineries, aluminum smelters, rolling mills, and energy generation facilities have not been recorded in the Consolidated Financial Statements due to uncertainties surrounding the ultimate settlement date. Such uncertainties exist as a result of the perpetual nature of the structures, maintenance and upgrade programs, and other factors. At the date a reasonable estimate of the ultimate settlement date can be made (e.g., planned demolition), Alcoa Corporation would record an ARO for the removal, treatment, transportation, storage, and/or disposal of various regulated assets and hazardous materials such as asbestos, underground and aboveground storage tanks, PCBs, various process residuals, solid wastes, electronic equipment waste, and various other materials. If Alcoa Corporation was required to demolish all such structures immediately, the estimated CARO as of December 31, 2018 ranges from $3 to $28 per structure (24 structures) in today’s dollars.

The following table details the carrying value of recorded AROs by major category (of which $122 and $108 was classified as a current liability as of December 31, 2018 and 2017, respectively):

December 31,	2018		2017
Mine reclamation	$	198	$	221
Closure of bauxite residue areas		231		238
Spent pot lining disposal		113		125
Demolition*		76		113
Landfill closure		33		27
Other		—		1
	$	651	$	725

^*	In 2018, 2017, and 2016, AROs were recorded as a result of management’s decision to permanently close and demolish certain structures (see Note D).

The following table details the changes in the total carrying value of recorded AROs:

December 31,	2018			2017
Balance at beginning of year	$	725		$	708
Accretion expense		17			17
Payments		(80	)		(69	)
Liabilities incurred		63			70
Reversals of previously recorded liabilities*		(37	)		(27	)
Foreign currency translation and other		(37	)		26
Balance at end of year	$	651		$	725

^*	In 2018 and 2017, Reversals of previously recorded liabilities include $36 and $20 related to the Portovesme (Italy) and Warrick (Indiana) smelters, respectively (see Note D).