13. Supplemental Balance Sheet Information

INVENTORIES

Total inventories consisted of the following:


	As of		As of
	September 30,		December 31,
(millions)	2011		2010

Finished goods and work in progress	$	252	$	227
Raw materials		68		63

Total	$	320	$	290

ASSET RETIREMENT OBLIGATIONS

Changes in the liability for asset retirement obligations consisted of the following:


	Nine Months
	ended September 30,
(millions)	2011			2010

Balance as of January 1	$	103		$	101
Accretion expense		5			5
Liabilities incurred/adjusted (a)		12			(1	)
Liabilities settled		(1	)		(1	)
Asset retirements		(1	)		(1	)
Foreign currency translation		(1	)		—

Balance as of September 30	$	117		$	103


(a)		Liabilities incurred/adjusted for the nine months ended September 30, 2011 include $10 million for the acceleration of the asset retirement obligation related to the decision to permanently close our gypsum quarry and ship loading facility in Windsor, Nova Scotia, Canada.

PROPERTY, PLANT AND EQUIPMENT

As of September 30, 2011, we had $7 million of net property, plant and equipment included in other current assets on the condensed consolidated balance sheet classified as “assets held for sale.” These assets are primarily owned by United States Gypsum Company. Assets held for sale as of December 31, 2010 amounted to $7 million.