Property, Plant, and Equipment (Tables)

12 Months Ended

Dec. 31, 2015

Property, Plant and Equipment [Abstract]

Property, plant, and equipment

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

	December 31
Millions of dollars	2015		2014
Land	$	232	$	217
Buildings and property improvements	3,359		3,311
Machinery, equipment, and other	17,109		19,954
Total	20,700		23,482
Less accumulated depreciation	9,789		11,007
Net property, plant, and equipment	$	10,911	$	12,475

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
	2015	2014
1    -   10 years	12%	12%
11    -   20 years	41%	42%
21    -   30 years	22%	21%
31    -   40 years	25%	25%

	Machinery, Equipment, and Other
	2015	2014
1    -    5 years	23%	23%
6    -   10 years	69%	70%
11    -   20 years	8%	7%