Income Taxes - Components of deferred tax liabilities and assets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax liabilities:
Depreciation, depletion, and amortization	$ 628.0	$ 919.6
Partially-owned subsidiaries basis difference	117.2	171.5
Convertible debt	93.3	137.4
Total deferred tax liabilities	838.5	1,228.5
Deferred tax assets:
Workers compensation, pensions, and other benefits	23.8	46.7
Warranties and reserves	7.1	12.1
Equity items	32.0	52.6
Tax loss carryforwards and credits	33.7	24.9
Inventory	17.0	29.2
Accrued liabilities and other	10.9	6.5
Total deferred tax assets	124.5	172.0
Net deferred tax liabilities before valuation allowances	714.0	1,056.5
Valuation allowances	12.0	11.7
Net deferred tax liabilities before reserve for uncertain tax positions	726.0	1,068.2
Deferred tax assets included in reserve for uncertain tax positions	(2.1)	(11.2)
Adjusted net deferred tax liabilities	$ 723.9	$ 1,057.0