Property, Plant and Equipment

6 Months Ended

Jun. 30, 2018

Property, Plant and Equipment

Property, Plant and Equipment

10.Property, Plant and Equipment

	June 30,		December 31,
($ in millions)	2018		2017
Land	$	170	$	172
Buildings		1,318		1,390
Machinery and equipment		5,034		5,282
Construction-in-progress		554		542
		7,076		7,386
Accumulated depreciation		(2,603)		(2,776)
	$	4,473	$	4,610

Property, plant and equipment are stated at historical or acquired cost. Depreciation expense amounted to $129 million and $254 million for the three and six months ended June 30, 2018, respectively, and $153 million and $260 million for the comparable periods in 2017, respectively. During the three months ended June 30, 2017, cumulative catch-up depreciation recorded as a result of changes in the values and useful lives of fixed assets associated with the finalization of the valuation for the Rexam acquisition was $35 million, of which $11 million related to the three months ended March 31, 2017, and $24 million related to the six months ended December 31, 2016.