Property, Plant, and Equipment (Tables)

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

Property, plant, and equipment

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

	December 31
Millions of dollars	2020		2019
Land	$	120	$	202
Buildings and property improvements	1,652		3,167
Machinery, equipment, and other	13,592		16,571
Total	15,364		19,940
Less accumulated depreciation	11,039		12,630
Net property, plant, and equipment	$	4,325	$	7,310

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 are depreciated over the following useful lives:

	Buildings and Property Improvements
	2020	2019
1    -   10 years	13%	12%
11    -   20 years	41%	41%
21    -   30 years	21%	22%
31    -   40 years	25%	25%

	Machinery, Equipment, and Other
	2020	2019
1    -    5 years	49%	43%
6    -   10 years	41%	47%
11    -   20 years	10%	10%