OTHER NONCURRENT ASSETS
 12 Months Ended
Dec. 31, 2013
OTHER NONCURRENT ASSETS  
OTHER NONCURRENT ASSETS

9. OTHER NONCURRENT ASSETS

        Other noncurrent assets consisted of the following (dollars in millions):

 
   2013   2012  

Pension assets

   $ 20   $ 1  

Debt issuance costs

     32     29  

Capitalized turnaround costs

     192     127  

Spare parts inventory

     100     93  

Catalyst assets

     26     25  

Deposits

     41     33  

Other

     47     58  
           
​ ​ ​ ​ ​ ​ ​ ​

Total

   $ 458   $ 366  
           
​ ​ ​ ​ ​ ​ ​ ​
​ ​ ​ ​ ​ ​ ​ ​
           

        Amortization expense of catalyst assets for the years ended December 31, 2013, 2012 and 2011 was $12 million, $10 million and $12 million, respectively.