The following table summarizes the valuation techniques and significant unobservable inputs used in the fair value measurement  level 3 financial instruments: Relationship of unobservable  input(s) to fair value Significant  unobservable input(s) Valuation technique(s) Type of asset/liability Net asset valuation Investment in common shares  Warrants  Interest of others in  consolidated funds  Black-Scholes model Discounted cash flows • Forward exchange  rates (from  observable forward  exchange rates  at the end of the  reporting period) • Increases (decreases) in the  forward exchange rate would  increase (decrease) fair value • Discount rate • Increases (decreases) in discount rate  will decrease (increase) the fair value • Increases (decreases) in volatility  would increase (decrease) fair value • Volatility • Future cash flows • Increases (decreases) in future cash  flows increase (decrease) fair value • Increases (decreases) in discount rate  will decrease (increase) the fair value • Discount rate • Terminal  capitalization rate • Increases (decreases) in terminal  capitalization rate will decrease  (increase) the fair value • Increases (decreases) in the  investment horizon will increase  (decrease) the fair value • Investment horizon The following table presents the change in the balance of financial assets and liabilities classified as Level 3 as at December 31, 2013  and December 31, 2012: There were no transfers in or out of level 3 financial assets or liabilities in 2013 or 2012. 1.  Includes foreign currency translation 7.  ACCOUNTS RECEIVABLE AND OTHER Financial Assets Financial Liabilities (MILLIONS) 2013 2012 2013 2012 Balance at beginning of year  $ 2,334 $ 1,820 $ 680 $ 618 Fair value changes in net income  (24) 20 (35) (17) Fair value changes in other comprehensive income 1 104 111 36 (21) Additions, net of disposals  315 383 408 100 Balance at end of year  $ 2,729 $ 2,334 $ 1,089 $ 680 (MILLIONS) Note Dec. 31, 2013 Dec. 31, 2012 Accounts receivable  (a) $ 4,299 $ 4,379 Prepaid expenses and other assets  1,490 1,727 Restricted cash  (b) 877 846 Total  $ 6,666 $ 6,952 (MILLIONS) Dec. 31, 2013 Dec. 31, 2012 Current  $ 4,840 $ 4,996 Non-current  1,826 1,956 Total  $ 6,666 $ 6,952 a)  Accounts Receivable The current and non-current balances of accounts receivable and other are as follows: Accounts receivable includes $592 million (2012 – $647 million) of unrealized mark-to-market gains on energy sales contracts and  $764 million (2012 – $994 million) of completed contracts and work-in-progress related to contracted sales from the company’s  112 BROOKFIELD ASSET MANAGEMENT 