cash settlement value of our open fuel hedge contracts at December 31, 2013 based on their contract settlement dates, assuming the same 10% and 20% changes.  

Interest Rate Risk  

 

Our exposure to market risk from adverse changes in interest rates is primarily associated with our long-term debt obligations. Market risk associated with our fixed and variable rate long-term debt relates to the potential reduction in fair value and negative impact to future earnings, respectively, from an increase in interest rates.  

 

At December 31, 2013 , we had $4.9 billion of fixed-rate long-term debt and $6.3 billion of variable-rate long-term debt. An increase of 100 basis points in average annual interest rates would have decreased the estimated fair value of our fixed-rate long-term debt by $210 million at December 31, 2013 and would have increased the annual interest expense on our variable-rate long-term debt by $44 million, exclusive of the impact of our interest rate hedge contracts.  

 

Foreign Currency Exchange Risk  

 

We are subject to foreign currency exchange rate risk because we have revenue and expense denominated in foreign currencies with our primary exposures being the Japanese yen and Canadian dollar. To manage exchange rate risk, we execute both our international revenue and expense transactions in the same foreign currency to the extent practicable. From time to time, we may also enter into foreign currency option and forward contracts. At December 31, 2013 , we had open foreign currency forward contracts totaling a $257 million asset position. We estimate that a 10% depreciation or appreciation in the price of the Japanese yen and Canadian dollar in relation to the U.S. dollar would change the projected cash settlement value of our open hedge contracts by a $80 million gain or $100 million loss, respectively, for the year ending December 31, 2014.