Level 3 – Significant Unobservable Inputs Unobservable (supported by little or no market activity) prices. We include investments in debt securities in Level 3 of the fair value hierarchy because they trade infrequently and  have little price transparency. We review the fair value of these instruments periodically and estimate an impairment  charge based on management’s best estimates, which are unobservable inputs. The fair values of our financial assets and liabilities measured at fair value on a recurring basis at December 31, 2012  and 2011 are summarized in the following table: For our non-financial assets and liabilities measured at fair value on a non-recurring basis, no fair value measurements  were made during the years ended December 31, 2012 or 2011. Generations 131 (Cdn$ in millions)  2012 2011  Level 1   Level 2   Level 3   Total  Level 1   Level 2   Level 3  Total Financial assets Marketable equity securities  $  671  $  –  $  –  $ 671 $ 511 $ – $ – $ 511 Marketable debt securities  –  –  16  16 – – 14 14 Settlements receivable – 705 – 705 – 559 – 559 Derivative instruments – 3 – 3 – 318 – 318 $ 671  $ 708  $  16  $ 1,395 $ 511 $ 877 $ 14 $ 1,402 Financial liabilities Derivative instruments $ – $ 11 $ – $ 11 $ – $ 7 $ – $  7 Settlements payable – 68 – 68 – 35 – 35 $  –  $  79  $  –  $ 79 $ – $ 42 $ – $ 42