Property, Plant and Equipment

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

PROPERTY, PLANT AND EQUIPMENT

Property, plant and equipment are comprised of the following at December 31:

	Useful Life	2017		2016
Land and improvements (1)	8 - 20 years (1)	$	413	$	130
Buildings, structures and related equipment	5 - 40 years	3,168		1,344
Machinery, equipment and other	2 - 20 years	6,195		2,916
Total cost		9,776		4,390
Less: Accumulated depreciation		2,817		2,065
Property, plant and equipment, less accumulated depreciation		$	6,959	$	2,325

⁽¹⁾  Useful life excludes land.

Depreciation expense relating to property, plant and equipment was $716 million, $311 million and $351 million in 2017, 2016 and 2015, respectively. See "Note 18. Restructuring, impairment and other" for additional information on property, plant and equipment impairments.