INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Components of income tax provision

	Years ended December 31,
	2018			2017			2016
Components of Income (Loss) Before Taxes	($ in millions)
Domestic	$	288.0		$	53.3		$	(23.3	)
Foreign	149.3			63.9			(10.9		)
Income (loss) before taxes	$	437.3		$	117.2		$	(34.2	)
Components of Income Tax Provision (Benefit)
Current expense (benefit):
Federal	$	21.7		$	(4.0	)	$	(11.6	)
State	5.1			3.0			0.9
Foreign	48.0			24.1			15.7
	74.8			23.1			5.0
Deferred expense (benefit):
Federal	27.0			(549.6		)	(10.1		)
State	(0.8		)	14.6			(5.1		)
Foreign	8.4			79.6			(20.1		)
	34.6			(455.4		)	(35.3		)
Income tax provision (benefit)	$	109.4		$	(432.3	)	$	(30.3	)

Effective tax rate reconciliation

The following table accounts for the difference between the actual tax provision and the amounts obtained by applying the statutory U.S. federal income tax rate to the income (loss) before taxes.

	Years ended December 31,
Effective Tax Rate Reconciliation (Percent)	2018		2017		2016
Statutory federal tax rate	21.0	%	35.0	%	35.0	%
State income taxes, net	2.0		(1.2	)	8.0
Foreign rate differential	1.8		(7.7	)	(25.1	)
U.S. tax on foreign earnings	1.1		(70.8	)	24.4
Salt depletion	(2.4	)	(16.1	)	45.4
Change in valuation allowance	3.8		76.0		(0.7	)
Remeasurement of U.S. state deferred taxes	(0.6	)	10.2		9.4
Change in tax contingencies	(0.7	)	(7.7	)	(9.7	)
U.S. Tax Cuts and Jobs Act	(0.8	)	(373.5	)	—
Share-based payments	—		(5.7	)	—
Dividends paid to Contributing Employee Ownership Plan	(0.1	)	(0.6	)	2.8
Return to provision	(0.1	)	(0.6	)	5.3
U.S. Federal tax credits	(0.4	)	(4.2	)	0.6
Other, net	0.4		(2.0	)	(6.8	)
Effective tax rate	25.0	%	(368.9	)%	88.6	%

Components of deferred tax assets and liabilities

	December 31,
Components of Deferred Tax Assets and Liabilities	2018			2017
Deferred tax assets:	($ in millions)
Pension and postretirement benefits	$	156.8		$	147.3
Environmental reserves	31.9			33.2
Asset retirement obligations	15.5			14.0
Accrued liabilities	37.0			37.6
Tax credits	19.5			37.1
Net operating losses	50.2			53.3
Capital loss carryforward	2.0			2.1
Other miscellaneous items	23.9			11.2
Total deferred tax assets	336.8			335.8
Valuation allowance	(147.4		)	(121.4		)
Net deferred tax assets	189.4			214.4
Deferred tax liabilities:
Property, plant and equipment	541.8			550.3
Intangible amortization	61.6			67.3
Inventory and prepaids	8.3			1.0
Partnerships	65.2			67.5
Taxes on unremitted earnings	5.1			3.1
Total deferred tax liabilities	682.0			689.2
Net deferred tax liability	$	(492.6	)	$	(474.8	)

Summary of Valuation Allowance

The activity of our deferred income tax valuation allowance was as follows:

	December 31,
	2018			2017
	($ in millions)
Beginning balance	$	121.4		$	29.0
Increases to valuation allowances	31.9			94.5
U.S. Tax Cuts and Jobs Act	—			2.2
Decreases to valuation allowances	(0.9		)	(5.0		)
Currency translation adjustment	(5.0		)	0.7
Ending balance	$	147.4		$	121.4

Unrecognized tax benefits

The amounts of unrecognized tax benefits were as follows:

	December 31,
	2018			2017
	($ in millions)
Beginning balance	$	36.3		$	38.4
Increase for current year tax positions	2.1			2.9
Increase for prior year tax positions	0.3			5.4
Reductions due to statute of limitations	—			(0.1		)
Decrease for prior year tax positions	(4.9		)	(9.2		)
Decrease due to tax settlements	—			(1.1		)
Ending balance	$	33.8		$	36.3

Tax years subject to examination

For our primary tax jurisdictions, the tax years that remain subject to examination are as follows:

	Tax Years
U.S. federal income tax	2013 - 2017
U.S. state income tax	2006 - 2017
Canadian federal income tax	2012 - 2017
Brazil	2014 - 2017
Germany	2015 - 2017
China	2014 - 2017
The Netherlands	2014 - 2017