SUPPLEMENTAL FINANCIAL STATEMENT INFORMATION

Temporary Investments

Temporary investments with an original maturity of three months or less are treated as cash equivalents and are stated at cost. Temporary investments totaled $2.1 billion and $738 million at September 30, 2016 and December 31, 2015, respectively.

Accounts and Notes Receivable



In millions	September 30, 2016		December 31, 2015
Accounts and notes receivable, net:
Trade	$	2,594	$	2,480
Other	213		195
Total	$	2,807	$	2,675

The allowance for doubtful accounts was $72 million and $70 million at September 30, 2016 and December 31, 2015, respectively.

Inventories



In millions	September 30, 2016		December 31, 2015
Raw materials	$	303	$	339
Finished pulp, paper and packaging	1,192		1,248
Operating supplies	609		563
Other	118		78
Total	$	2,222	$	2,228

Depreciation

Accumulated depreciation was $21.5 billion and $20.7 billion at September 30, 2016 and December 31, 2015. Depreciation expense was $294 million and $309 million for the three months ended September 30, 2016 and 2015, respectively, and $845 million and $919 million for the nine months ended September 30, 2016 and 2015, respectively.

Interest

Interest payments made during the nine months ended September 30, 2016 and 2015 were $511 million and $471 million, respectively.

Amounts related to interest were as follows:



	Three Months Ended September 30,				Nine Months Ended September 30,
In millions	2016		2015		2016		2015
Interest expense (a)	$	181	$	158	$	513	$	481
Interest income (a)	49		17		129		59
Capitalized interest costs	7		5		21		19


(a)	Interest expense and interest income exclude approximately $7 million and $25 million for the three months and nine months ended September 30, 2015, related to investments in and borrowings from variable interest entities for which the Company had a legal right of offset (see Note 13).