Property, Plant and Equipment

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, Plant and Equipment

The components of our property, plant and equipment balance are as follows:

	Estimated Useful Lives in Years	December 31,
Dollars in millions		2019			2018
Land	N/A	$	5		$	5
Buildings and property improvements	1-35	124			122
Equipment and other	1-25	387			349
Total		516			476
Less accumulated depreciation		(386		)	(355		)
Net property, plant and equipment		$	130		$	121

Depreciation expense was $33 million, $31 million, and $27 million for the years ended December 31, 2019, 2018, and 2017, respectively.