December 31, | ||||||||||||||
(Millions of dollars) | Useful Lives (Years) | 2013 | 2012 | 2011 | ||||||||||
Land | — | $ | 688 | $ | 723 | $ | 753 | |||||||
Buildings and land improvements | 20-45 | 6,928 | 6,214 | 5,857 | ||||||||||
Machinery, equipment and other | 3-10 | 16,793 | 16,073 | 14,435 | ||||||||||
Equipment leased to others | 1-10 | 5,365 | 4,658 | 4,285 | ||||||||||
Construction-in-process | — | 1,542 | 2,264 | 1,996 | ||||||||||
Total property, plant and equipment, at cost | 31,316 | 29,932 | 27,326 | |||||||||||
Less: Accumulated depreciation | (14,241 | ) | (13,471 | ) | (12,931 | ) | ||||||||
Property, plant and equipment–net | $ | 17,075 | $ | 16,461 | $ | 14,395 | ||||||||