level 3 financial assets as of december 2017 decreased compared with december 2016 , primarily reflecting a decrease in level 3 cash instruments . see notes 6 through 8 for further information about level 3 financial assets ( including information about unrealized gains and losses related to level 3 financial assets and financial liabilities , and transfers in and out of level 3 ) . note 6 . cash instruments cash instruments include u.s . government and agency obligations , non-u.s