Property, Plant, and Equipment

12 Months Ended

Dec. 31, 2015

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

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%