liquidity monitoring and measurement stress testing liquidity stress testing is performed for each of citi 2019s major entities , operating subsidiaries and/or countries . stress testing and scenario analyses are intended to quantify the potential impact of a liquidity event on the balance sheet and liquidity position , and to identify viable funding alternatives that can be utilized . these scenarios include assumptions about significant changes in key funding sources , market triggers ( such as credit ratings ) , potential uses of funding and political and economic conditions in certain countries . these conditions include expected and stressed market conditions as well as company- specific events . liquidity stress tests are conducted to ascertain potential mismatches between liquidity sources and uses over a variety of time horizons ( overnight , one week , two weeks , one month , three months , one year ) and over a variety of stressed conditions . liquidity limits are set accordingly . to monitor the liquidity of an entity , these stress tests and potential mismatches are calculated with varying frequencies , with several tests performed daily . given the range of potential stresses , citi maintains a series of contingency funding plans on a consolidated basis and for individual entities . these plans specify a wide range of readily available actions for a variety of adverse market conditions or idiosyncratic stresses . short-term liquidity measurement : liquidity coverage ratio ( lcr ) in addition to internal measures that citi has developed for a 30-day stress scenario , citi also monitors its liquidity by reference to the lcr , as calculated pursuant to the u.s . lcr rules . generally , the lcr is designed to ensure that banks maintain an adequate level of hqla to meet liquidity needs under an acute 30-day stress scenario . the lcr is calculated by dividing hqla by estimated net outflows over a stressed 30-day period , with the net outflows determined by applying prescribed outflow factors to various categories of liabilities , such as deposits , unsecured and secured wholesale borrowings , unused lending commitments and derivatives- related exposures , partially offset by inflows from assets maturing within 30 days . banks are required to calculate an add-on to address potential maturity mismatches between contractual cash outflows and inflows within the 30-day period in determining the total amount of net outflows . the minimum lcr requirement is 90% ( 90 % ) effective january 2016 , increasing to 100% ( 100 % ) in january 2017 . the table below sets forth the components of citi 2019s lcr calculation and hqla in excess of net outflows as of the periods indicated : in billions of dollars dec . 31 , sept . 30 , dec . 31 .
what was the difference in billions in hqla from dec . 31 , 2014 to dec . 31 , 2015?
as set forth in the table above , citi 2019s lcr was unchanged both year-over-year and quarter-over-quarter , as the reduction in citi 2019s hqla was offset by a reduction in net outflows , reflecting reductions in citi 2019s long-term debt and short-term borrowings . long-term liquidity measurement : net stable funding ratio ( nsfr ) for 12-month liquidity stress periods , citi uses several measures , including its internal long-term liquidity measure , based on a 12-month scenario assuming deterioration due to a combination of idiosyncratic and market stresses of moderate to high severity . it is broadly defined as the ratio of unencumbered liquidity resources to net stressed cumulative outflows over a 12-month period . in addition , in october 2014 , the basel committee on banking supervision ( basel committee ) issued final standards for the implementation of the basel iii nsfr , with full compliance required by january 1 , 2018 . similar to citi 2019s internal long-term liquidity measure , the nsfr is intended to measure the stability of a banking organization 2019s funding over a one-year time horizon . pursuant to the basel committee 2019s final standards , the nsfr is calculated by dividing the level of a bank 2019s available stable funding by its required stable funding . the ratio is required to be greater than 100% ( 100 % ) . under the basel committee standards , available stable funding primarily includes portions of equity , deposits and long-term debt , while required stable funding primarily includes the portion of long-term assets which are deemed illiquid . the u.s . banking agencies have not yet proposed the u.s . version of the nsfr , although a proposal is expected during 2016. .