PROPERTY, PLANT AND EQUIPMENT

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT AND EQUIPMENT

NOTE 11. PROPERTY, PLANT AND EQUIPMENT

		December 31,
	Useful Lives	2018			2017
		($ in millions)
Land and improvements to land	10-20 Years	$	276.9		$	281.7
Buildings and building equipment	10-30 Years	387.6			382.4
Machinery and equipment	3-20 Years	5,252.0			5,028.4
Leasehold improvements		5.2			3.9
Construction in progress		341.4			212.5
Property, plant and equipment		6,263.1			5,908.9
Accumulated depreciation		(2,781.0		)	(2,333.1		)
Property, plant and equipment, net		$	3,482.1		$	3,575.8

The weighted-average useful life of machinery and equipment at December 31, 2018 was 11 years. Depreciation expense was $497.8 million, $465.1 million and $435.7 million for 2018, 2017 and 2016, respectively.  Interest capitalized was $6.0 million, $3.0 million and $1.9 million for 2018, 2017 and 2016, respectively.

The consolidated statements of cash flows for the years ended December 31, 2018, 2017 and 2016, included decreases of $25.5 million, $0.5 million and $29.9 million, respectively, to capital expenditures, with the corresponding change to accounts payable and accrued liabilities, related to purchases of property, plant and equipment included in accounts payable and accrued liabilities at December 31, 2018, 2017 and 2016.

During 2016, we entered into sale/leaseback transactions for railcars that we acquired in connection with the Acquisition. We received proceeds from the sales of $40.4 million for the year ended December 31, 2016.