text: We also manage our exposure to fluctuating interest rates and we have 
  fixed the interest rate on 95.3% of our debt including short-term 
  borrowings at December 31, 2013 (2012 – 100%). 
  All of our Debt Derivatives currently outstanding have been designated 
  as effective hedges against 
  foreign exchange risk for accounting 
  purposes as described below and in note 20 to the consolidated 
  financial statements. 
  
  **Debt Derivatives**
  We use cross currency interest exchange agreements (Debt Derivatives), 
  to hedge the foreign exchange risk on all of the principal and interest 
  obligations of our US dollar denominated senior notes and debentures. 
  At December 31, 2013 we used Debt Derivatives to hedge the foreign 
  exchange risk on 100% of the principal and interest obligations on all 
  our US dollar denominated debt. We use Debt Derivatives for risk 
  management purposes only. 
  Subtotal  US$ 1,000  $ 1,030 
  
  During 2013, we completed Debt Derivatives transactions as follows: 
  (cid:129) entered into new Debt Derivatives to hedge senior notes issued in 
  US$  850  2023  4.10%  4.59%  $  877 
  October 2, 2013  US$  650  2043  5.45%  5.61%  $  671 
  
  US$ 1,500  $ 1,548 