conditions and changes to regulatory capital requirements under basel iii capital standards . beginning in 2014 , other comprehensive income related to available for sale securities ( as well as pension and other post-retirement plans ) are included in pnc 2019s regulatory capital ( subject to a phase-in schedule ) and , therefore will affect pnc 2019s regulatory capital ratios . for additional information , see the supervision and regulation section in item 1 2013 business and the capital portion of the balance sheet review section in this item 7 of this report . the duration of investment securities was 2.9 years at december 31 , 2013 . we estimate that , at december 31 , 2013 , the effective duration of investment securities was 3.0 years for an immediate 50 basis points parallel increase in interest rates and 2.8 years for an immediate 50 basis points parallel decrease in interest rates . comparable amounts at december 31 , 2012 were 2.3 years and 2.2 years , respectively . we conduct a quarterly comprehensive security-level impairment assessment on all securities . for securities in an unrealized loss position , we determine whether the loss represents otti . for debt securities that we neither intend to sell nor believe we will be required to sell prior to expected recovery , we recognize the credit portion of otti charges in current earnings and include the noncredit portion of otti in net unrealized gains ( losses ) on otti securities on our consolidated statement of comprehensive income and net of tax in accumulated other comprehensive income ( loss ) on our consolidated balance sheet . during 2013 and 2012 we recognized otti credit losses of $ 16 million and $ 111 million , respectively . substantially all of the credit losses related to residential mortgage-backed and asset-backed securities collateralized by non-agency residential loans . if current housing and economic conditions were to deteriorate from current levels , and if market volatility and illiquidity were to deteriorate from current levels , or if market interest rates were to increase or credit spreads were to widen appreciably , the valuation of our investment securities portfolio could be adversely affected and we could incur additional otti credit losses that would impact our consolidated income statement . additional information regarding our investment securities is included in note 8 investment securities and note 9 fair value in the notes to consolidated financial statements included in item 8 of this report . loans held for sale table 15 : loans held for sale in millions december 31 december 31 .

december 312013: commercial mortgages at fair value: 586
commercial mortgages at lower of cost or fair value: 281
total commercial mortgages: 867
residential mortgages at fair value: 1315
residential mortgages at lower of cost or fair value: 41
total residential mortgages: 1356
other: 32
total: 2255
december 312012: commercial mortgages at fair value: 772
commercial mortgages at lower of cost or fair value: 620
total commercial mortgages: 1392
residential mortgages at fair value: 2096
residential mortgages at lower of cost or fair value: 124
total residential mortgages: 2220
other: 81
total: 3693

for commercial mortgages held for sale designated at fair value , we stopped originating these and continue to pursue opportunities to reduce these positions . at december 31 , 2013 , the balance relating to these loans was $ 586 million compared to $ 772 million at december 31 , 2012 . for commercial mortgages held for sale carried at lower of cost or fair value , we sold $ 2.8 billion in 2013 compared to $ 2.2 billion in 2012 . all of these loan sales were to government agencies . total gains of $ 79 million were recognized on the valuation and sale of commercial mortgage loans held for sale , net of hedges , in 2013 , and $ 41 million in 2012 . residential mortgage loan origination volume was $ 15.1 billion in 2013 compared to $ 15.2 billion in 2012 . substantially all such loans were originated under agency or federal housing administration ( fha ) standards . we sold $ 14.7 billion of loans and recognized related gains of $ 568 million in 2013 . the comparable amounts for 2012 were $ 13.8 billion and $ 747 million , respectively . interest income on loans held for sale was $ 157 million in 2013 and $ 168 million in 2012 . these amounts are included in other interest income on our consolidated income statement . additional information regarding our loan sale and servicing activities is included in note 3 loan sales and servicing activities and variable interest entities and note 9 fair value in our notes to consolidated financial statements included in item 8 of this report . goodwill and other intangible assets goodwill and other intangible assets totaled $ 11.3 billion at december 31 , 2013 and $ 10.9 billion at december 31 , 2012 . the increase of $ .4 billion was primarily due to additions to and changes in value of mortgage and other loan servicing rights . see additional information regarding our goodwill and intangible assets in note 10 goodwill and other intangible assets included in the notes to consolidated financial statements in item 8 of this report . 44 the pnc financial services group , inc . 2013 form 10-k .

Questions:
between the years of 2012 and 2013, what was the change in the total of residential mortgages, in millions?
and what was the combined total of those mortgages in the two years, also in millions?

Answers:
-864
3576