3M CO | 2013 | FY | 3


Amortization expense for the years ended December 31 follows:
          
(Millions)  2013  2012  2011
Amortization expense  $236 $233 $235

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(Millions)20132012
Patents  $ 602 $ 596
Other amortizable intangible assets (primarily tradenames and customer related      
 intangibles)    2,445   2,456
Total gross carrying amount  $ 3,047 $ 3,052
        
Accumulated amortization — patents    (458)   (421)
Accumulated amortization — other    (1,030)   (833)
Total accumulated amortization  $ (1,488) $ (1,254)
        
 Total finite-lived intangible assets — net  $ 1,559 $ 1,798
        
Non-amortizable intangible assets (primarily tradenames)   129   127
 Total intangible assets — net $ 1,688 $ 1,925

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   Dec. 31, 2012 2012 Dec. 31, 2013 2013 Dec. 31,
   2011 acquisition translation 2012 acquisition translation  2013
(Millions) Balance activity and other Balance activity and other Balance
Industrial $ 1,972 $ 204 $ (2) $ 2,174 $ 10 $ (18) $ 2,166
Safety and Graphics   1,713   41   (3)   1,751     (11)   1,740
Electronics and Energy   1,608     14   1,622     (10)   1,612
Health Care   1,508   88   2   1,598     (2)   1,596
Consumer   246   6   (12)   240     (9)   231
Total Company  $ 7,047 $ 339 $ (1) $ 7,385 $ 10 $ (50) $ 7,345

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Expected amortization expense for acquired amortizable intangible assets recorded as of December 31, 2013 follows:
                  
           After
(Millions)201420152016201720182018
Amortization expense $ 214 $ 200 $ 186 $ 171 $ 154 $ 634

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