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 $871 million and $738 million at June 30, 2016 and December 31, 2015, respectively.

Accounts and Notes Receivable



In millions	June 30, 2016		December 31, 2015
Accounts and notes receivable, net:
Trade	$	2,573	$	2,480
Other	264		195
Total	$	2,837	$	2,675

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

Inventories



In millions	June 30, 2016		December 31, 2015
Raw materials	$	312	$	339
Finished pulp, paper and packaging	1,163		1,248
Operating supplies	583		563
Other	107		78
Total	$	2,165	$	2,228

Depreciation

Accumulated depreciation was $21.2 billion and $20.7 billion at June 30, 2016 and December 31, 2015. Depreciation expense was $284 million and $306 million for the three months ended June 30, 2016 and 2015, respectively, and $551 million and $610 million for the six months ended June 30, 2016 and 2015, respectively.

Asset Retirement Obligations

There was no material activity related to asset retirement obligations during either of the six months ended June 30, 2016 or 2015.

Interest

Interest payments made during the six months ended June 30, 2016 and 2015 were $333 million and $349 million, respectively.

Amounts related to interest were as follows:



	Three Months Ended June 30,				Six Months Ended June 30,
In millions	2016		2015		2016		2015
Interest expense (a)	$	172	$	164	$	332	$	323
Interest income (a)	43		20		80		42
Capitalized interest costs	7		7		14		14


(a)	Interest expense and interest income exclude approximately $9 million and $18 million for the three months and six months ended June 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).