troubled debt restructurings ( tdrs ) a tdr is a loan whose terms have been restructured in a manner that grants a concession to a borrower experiencing financial difficulties . tdrs result from our loss mitigation activities , and include rate reductions , principal forgiveness , postponement/reduction of scheduled amortization , and extensions , which are intended to minimize economic loss and to avoid foreclosure or repossession of collateral . additionally , tdrs also result from borrowers that have been discharged from personal liability through chapter 7 bankruptcy and have not formally reaffirmed their loan obligations to pnc . in those situations where principal is forgiven , the amount of such principal forgiveness is immediately charged off . some tdrs may not ultimately result in the full collection of principal and interest , as restructured , and result in potential incremental losses . these potential incremental losses have been factored into our overall alll estimate . the level of any subsequent defaults will likely be affected by future economic conditions . once a loan becomes a tdr , it will continue to be reported as a tdr until it is ultimately repaid in full , the collateral is foreclosed upon , or it is fully charged off . we held specific reserves in the alll of $ .5 billion and $ .6 billion at december 31 , 2013 and december 31 , 2012 , respectively , for the total tdr portfolio . table 70 : summary of troubled debt restructurings in millions dec . 31 dec . 31 .
what was the change in the balance in millions of nonperforming loans from 2012 to 2013?
( a ) accruing loans have demonstrated a period of at least six months of performance under the restructured terms and are excluded from nonperforming loans . loans where borrowers have been discharged from personal liability through chapter 7 bankruptcy and have not formally reaffirmed their loan obligations to pnc are not returned to accrual status . table 71 quantifies the number of loans that were classified as tdrs as well as the change in the recorded investments as a result of the tdr classification during 2013 , 2012 and 2011 . additionally , the table provides information about the types of tdr concessions . the principal forgiveness tdr category includes principal forgiveness and accrued interest forgiveness . these types of tdrs result in a write down of the recorded investment and a charge-off if such action has not already taken place . the rate reduction tdr category includes reduced interest rate and interest deferral . the tdrs within this category would result in reductions to future interest income . the other tdr category primarily includes consumer borrowers that have been discharged from personal liability through chapter 7 bankruptcy and have not formally reaffirmed their loan obligations to pnc , as well as postponement/reduction of scheduled amortization and contractual extensions for both consumer and commercial borrowers . in some cases , there have been multiple concessions granted on one loan . this is most common within the commercial loan portfolio . when there have been multiple concessions granted in the commercial loan portfolio , the principal forgiveness tdr was prioritized for purposes of determining the inclusion in the table below . for example , if there is principal forgiveness in conjunction with lower interest rate and postponement of amortization , the type of concession will be reported as principal forgiveness . second in priority would be rate reduction . for example , if there is an interest rate reduction in conjunction with postponement of amortization , the type of concession will be reported as a rate reduction . in the event that multiple concessions are granted on a consumer loan , concessions resulting from discharge from personal liability through chapter 7 bankruptcy without formal affirmation of the loan obligations to pnc would be prioritized and included in the other type of concession in the table below . after that , consumer loan concessions would follow the previously discussed priority of concessions for the commercial loan portfolio . 140 the pnc financial services group , inc . 2013 form 10-k .