SUPPLEMENTAL FINANCIAL STATEMENT INFORMATION

Temporary Investments



In millions	September 30, 2013		December 31, 2012
Temporary investments	$	1,545	$	934

Accounts and Notes Receivable



In millions	September 30, 2013		December 31, 2012
Accounts and notes receivable, net:
Trade	$	3,717	$	3,316
Other	307		246
Total	$	4,024	$	3,562

Inventories



In millions	September 30, 2013		December 31, 2012
Raw materials	$	410	$	360
Finished pulp, paper and packaging	1,792		1,728
Operating supplies	571		588
Other	68		54
Total	$	2,841	$	2,730

Depreciation Expense



	Three Months Ended September 30,				Nine Months Ended September 30,
In millions	2013		2012		2013		2012
Depreciation expense	$	365	$	347	$	1,081	$	1,045

Valuation Accounts

Certain valuation accounts were as follows:



In millions	September 30, 2013		December 31, 2012
Accumulated depreciation	$	19,826	$	18,934
Allowance for doubtful accounts	138		119

During the second quarter of 2013, a reserve of $28 million on $42 million of total receivables from a large envelope company was recorded due to their filing for bankruptcy protection in June 2013. The reserve is based on the Company's estimate of ultimate expected losses associated with the outstanding receivable balance.

There was no material activity related to asset retirement obligations during either of the nine months ended September 30, 2013 or 2012.

Interest

Cash payments related to interest were as follows:



	Nine Months Ended September 30,
In millions	2013		2012
Interest payments	$	537	$	496

Amounts related to interest were as follows:



	Three Months Ended September 30,				Nine Months Ended September 30,
In millions	2013		2012		2013		2012
Interest expense (a)	$	162	$	197	$	520	$	559
Interest income (a)	15		34		41		56
Capitalized interest costs	4		10		12		29


(a)	Interest expense and interest income exclude approximately $11 million and $35 million for the three months and nine months ended September 30, 2013 and $15 million and $35 million for the three months and nine months ended September 30, 2012, respectively, related to investments in and borrowings from variable interest entities for which the Company has a legal right of offset (see Note 13).

Postretirement Benefit Expense

The components of the Company’s postretirement benefit expense were as follows:



	Three Months Ended September 30,						Nine Months Ended September 30,
In millions	2013			2012			2013			2012
Service cost	$	—		$	1		$	1		$	2
Interest cost	4			5			11			15
Actuarial loss	2			3			5			8
Amortization of prior service credit	(6		)	(8		)	(18		)	(22		)
Net postretirement benefit expense	$	—		$	1		$	(1	)	$	3