agreements associated with the agency securitizations , most sale agreements do not provide for penalties or other remedies if we do not respond timely to investor indemnification or repurchase requests . origination and sale of residential mortgages is an ongoing business activity and , accordingly , management continually assesses the need to recognize indemnification and repurchase liabilities pursuant to the associated investor sale agreements . we establish indemnification and repurchase liabilities for estimated losses on sold first and second-lien mortgages and home equity loans/lines for which indemnification is expected to be provided or for loans that are expected to be repurchased . for the first and second-lien mortgage sold portfolio , we have established an indemnification and repurchase liability pursuant to investor sale agreements based on claims made and our estimate of future claims on a loan by loan basis . these relate primarily to loans originated during 2006-2008 . for the home equity loans/lines sold portfolio , we have established indemnification and repurchase liabilities based upon this same methodology for loans sold during 2005-2007 . indemnification and repurchase liabilities are initially recognized when loans are sold to investors and are subsequently evaluated by management . initial recognition and subsequent adjustments to the indemnification and repurchase liability for the sold residential mortgage portfolio are recognized in residential mortgage revenue on the consolidated income statement . since pnc is no longer engaged in the brokered home equity lending business , only subsequent adjustments are recognized to the home equity loans/lines indemnification and repurchase liability . these adjustments are recognized in other noninterest income on the consolidated income statement . management 2019s subsequent evaluation of these indemnification and repurchase liabilities is based upon trends in indemnification and repurchase requests , actual loss experience , risks in the underlying serviced loan portfolios , and current economic conditions . as part of its evaluation , management considers estimated loss projections over the life of the subject loan portfolio . at december 31 , 2011 and december 31 , 2010 , the total indemnification and repurchase liability for estimated losses on indemnification and repurchase claims totaled $ 130 million and $ 294 million , respectively , and was included in other liabilities on the consolidated balance sheet . an analysis of the changes in this liability during 2011 and 2010 follows : analysis of indemnification and repurchase liability for asserted claims and unasserted claims .
what is the difference in millions between residential mortgages as of jan 1 , 2011 and dec 31 , 2011?
( a ) repurchase obligation associated with sold loan portfolios of $ 121.4 billion and $ 139.8 billion at december 31 , 2011 and december 31 , 2010 , respectively . ( b ) repurchase obligation associated with sold loan portfolios of $ 4.5 billion and $ 6.5 billion at december 31 , 2011 and december 31 , 2010 , respectively . pnc is no longer engaged in the brokered home equity lending business , which was acquired with national city . management believes our indemnification and repurchase liabilities appropriately reflect the estimated probable losses on investor indemnification and repurchase claims at december 31 , 2011 and 2010 . while management seeks to obtain all relevant information in estimating the indemnification and repurchase liability , the estimation process is inherently uncertain and imprecise and , accordingly , it is reasonably possible that future indemnification and repurchase losses could be more or less than our established liability . factors that could affect our estimate include the volume of valid claims driven by investor strategies and behavior , our ability to successfully negotiate claims with investors , housing prices , and other economic conditions . at december 31 , 2011 , we estimate that it is reasonably possible that we could incur additional losses in excess of our indemnification and repurchase liability of up to $ 85 million . this estimate of potential additional losses in excess of our liability is based on assumed higher investor demands , lower claim rescissions , and lower home prices than our current assumptions . reinsurance agreements we have two wholly-owned captive insurance subsidiaries which provide reinsurance to third-party insurers related to insurance sold to our customers . these subsidiaries enter into various types of reinsurance agreements with third-party insurers where the subsidiary assumes the risk of loss through either an excess of loss or quota share agreement up to 100% ( 100 % ) reinsurance . in excess of loss agreements , these subsidiaries assume the risk of loss for an excess layer of coverage up to specified limits , once a defined first loss percentage is met . in quota share agreements , the subsidiaries and third-party insurers share the responsibility for payment of all claims . these subsidiaries provide reinsurance for accidental death & dismemberment , credit life , accident & health , lender placed 200 the pnc financial services group , inc . 2013 form 10-k .