Property, Plant, and Equipment (Tables)

12 Months Ended

Dec. 31, 2012

Property, Plant and Equipment [Abstract]

Property, plant, and equipment

Property, plant, and equipment were composed of the following:

	December 31
Millions of dollars	2012		2011
Land	$	145	$	123
Buildings and property improvements	1,861		1,609
Machinery, equipment, and other	16,307		13,856
Total	18,313		15,588
Less accumulated depreciation	8,056		7,096
Net property, plant, and equipment	$	10,257	$	8,492

Percentages of building and property improvements, and total machinery, and equipment and other, excluding oil and natural gas investments, depreciated over useful lives

Classes of assets, excluding oil and natural gas investments, are depreciated over the following useful lives:

	Buildings and Property Improvements
	2012	2011
1    -   10 years	14%	13%
11    -   20 years	46%	47%
21    -   30 years	14%	13%
31    -   40 years	26%	27%

	Machinery, Equipment, and Other
	2012	2011
1    -    5 years	20%	19%
6    -   10 years	74%	75%
11    -   20 years	6%	6%