| Amortization expense for the years ended December 31 follows: | |||||||||
| (Millions) | 2013 | 2012 | 2011 | ||||||
| Amortization expense | $ | 236 | $ | 233 | $ | 235 | |||
| (Millions) | 2013 | 2012 | |||||
| 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 | |||
| 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 | ||||||||
| Expected amortization expense for acquired amortizable intangible assets recorded as of December 31, 2013 follows: | ||||||||||||||||||
| After | ||||||||||||||||||
| (Millions) | 2014 | 2015 | 2016 | 2017 | 2018 | 2018 | ||||||||||||
| Amortization expense | $ | 214 | $ | 200 | $ | 186 | $ | 171 | $ | 154 | $ | 634 | ||||||