rates of interest and declining in periods of increasing rates of interest. Based upon quoted market prices and Level 2 inputs, the fair value of our total debt was $8.8 billion as of December 31, 2015. 

Foreign Exchange Risk 

During 2015 , net sales from our International segment accounted for 33% of our consolidated revenues. Net sales and related expenses generated from our internationally-focused websites, and from www.amazon.ca and www.amazon.com.mx (which are included in our North America segment), are primarily denominated in the functional currencies of the corresponding websites and primarily include Euros, Japanese Yen, and British Pounds. The results of operations of, and certain of our intercompany balances associated with, our internationally-focused websites and AWS are exposed to foreign exchange rate fluctuations. Upon consolidation, as foreign exchange rates vary, net sales and other operating results may differ materially from expectations, and we may record significant gains or losses on the remeasurement of intercompany balances. For example, as a result of fluctuations in foreign exchange rates during 2015 , International segment revenues decreased by $5.0 billion in comparison with the prior year. 

We have foreign exchange risk related to foreign-denominated cash, cash equivalents, and marketable securities (“foreign funds”). Based on the balance of foreign funds as of December 31, 2015 , of $7.3 billion , an assumed 5%, 10%, and 20% adverse change to foreign exchange would result in fair value declines of $365 million, $730 million, and $1.5 billion. All investments are classified as “available-for-sale.” Fluctuations in fair value are recorded in “Accumulated other comprehensive loss,” a separate component of stockholders’ equity. 

We have foreign exchange risk related to our intercompany balances denominated in various foreign currencies. Based on the intercompany balances as of December 31, 2015 , an assumed 5%, 10%, and 20% adverse change to foreign exchange would result in losses of $190 million, $405 million, and $905 million, recorded to “Other income (expense), net.” 

See Item 7 of Part II, “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Results of Operations—Effect of Foreign Exchange Rates” for additional information on the effect on reported results of changes in foreign exchange rates. 

Investment Risk 

As of December 31, 2015 , our recorded basis in equity investments was $280 million. These investments primarily relate to equity-method and cost-method investments in private companies. We review our investments for impairment when events and circumstances indicate that the decline in fair value of such assets below the carrying value is other-than-temporary. Our analysis includes a review of recent operating results and trends, recent sales/acquisitions of the investee securities, and other publicly available data. The current global economic climate provides additional uncertainty. Valuations of private companies are inherently more complex due to the lack of readily available market data. As such, we believe that market sensitivities are not practicable.