Guarantor and Non-Guarantor Financial Statements, Comprehensive Income Statements (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Net sales	$ 336.4	$ 338.9	$ 1,075.3	$ 1,018.1
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	267.3	280.4	864.4	838.8
Unrealized losses on derivative instruments	1.7	3.6	7.7	0.0
Depreciation and amortization	8.1	8.0	24.2	23.1
Selling, general, administrative, research and development	21.1	19.0	67.4	61.3
Net periodic postretirement benefit cost relating to Salaried VEBA	0.6	(6.0)	1.8	(17.7)
Gain on removal of Union VEBA net assets	(2.9)	0.0	490.9	0.0
Total selling, general, administrative, research and development	18.8	13.0	560.1	43.6
Total costs and expenses	295.9	306.3	1,456.4	907.0
Other operating charges, net	0.0	1.3	0.0	1.5
Operating (loss) income	40.5	32.6	(381.1)	111.1
Other (expense) income:
Interest expense	(4.9)	(9.7)	(19.9)	(27.7)
Other income (expense), net	(0.9)	2.2	(0.1)	5.9
(Loss) income before income taxes	34.7	25.1	(401.1)	89.3
Income tax (provision) benefit	(12.6)	(9.2)	151.2	(33.1)
Earnings in equity of subsidiaries	0.0	0.0	0.0	0.0
Net income	22.1	15.9	(249.9)	56.2
Comprehensive income	22.2	17.2	(182.5)	60.5
Parent
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Net sales	0.0	0.0	0.0	0.0
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	0.0	0.0	0.0	0.0
Unrealized losses on derivative instruments	0.0	0.0	0.0	0.0
Depreciation and amortization	0.0	0.0	0.0	0.0
Selling, general, administrative, research and development	0.9	0.9	3.3	3.1
Net periodic postretirement benefit cost relating to Salaried VEBA	0.0	0.0	0.0	0.0
Gain on removal of Union VEBA net assets	0.0		0.0
Total selling, general, administrative, research and development	0.9	0.9	3.3	3.1
Total costs and expenses	0.9	0.9	3.3	3.1
Other operating charges, net		0.0		0.0
Operating (loss) income	(0.9)	(0.9)	(3.3)	(3.1)
Other (expense) income:
Interest expense	(4.7)	(9.4)	(19.1)	(28.0)
Other income (expense), net	(0.6)	2.2	(0.6)	3.6
(Loss) income before income taxes	(6.2)	(8.1)	(23.0)	(27.5)
Income tax (provision) benefit	0.0	0.0	0.0	0.0
Earnings in equity of subsidiaries	28.3	24.0	(226.9)	83.7
Net income	22.1	15.9	(249.9)	56.2
Comprehensive income	22.2	17.2	(182.5)	60.5
Guarantor Subsidiaries
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Net sales	329.5	330.3	1,051.2	993.1
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	263.1	274.7	848.9	824.4
Unrealized losses on derivative instruments	1.7	3.6	7.7	0.0
Depreciation and amortization	7.8	7.7	23.3	22.3
Selling, general, administrative, research and development	18.4	17.2	58.6	52.3
Net periodic postretirement benefit cost relating to Salaried VEBA	0.6	(6.0)	1.8	(17.7)
Gain on removal of Union VEBA net assets	(2.9)		490.9
Total selling, general, administrative, research and development	16.1	11.2	551.3	34.6
Total costs and expenses	288.7	298.5	1,431.2	882.8
Other operating charges, net		1.3		1.5
Operating (loss) income	40.8	31.8	(380.0)	110.3
Other (expense) income:
Interest expense	(0.3)	(0.5)	(1.1)	(0.1)
Other income (expense), net	2.2	0.3	3.0	2.3
(Loss) income before income taxes	42.7	31.6	(378.1)	112.5
Income tax (provision) benefit	(15.6)	(11.9)	140.5	(42.3)
Earnings in equity of subsidiaries	(1.0)	1.6	2.2	3.4
Net income	26.1	21.3	(235.4)	73.6
Comprehensive income	26.5	22.5	(167.8)	77.7
Non-Guarantor Subsidiaries
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Net sales	29.4	33.6	97.6	100.7
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	25.3	29.8	85.8	87.9
Unrealized losses on derivative instruments	0.0	0.0	0.0	0.0
Depreciation and amortization	0.3	0.3	0.9	0.8
Selling, general, administrative, research and development	2.4	1.7	7.2	7.9
Net periodic postretirement benefit cost relating to Salaried VEBA	0.0	0.0	0.0	0.0
Gain on removal of Union VEBA net assets	0.0		0.0
Total selling, general, administrative, research and development	2.4	1.7	7.2	7.9
Total costs and expenses	28.0	31.8	93.9	96.6
Other operating charges, net		0.0		0.0
Operating (loss) income	1.4	1.8	3.7	4.1
Other (expense) income:
Interest expense	0.0	0.0	0.0	0.0
Other income (expense), net	(2.4)	(0.1)	(2.2)	0.4
(Loss) income before income taxes	(1.0)	1.7	1.5	4.5
Income tax (provision) benefit	0.8	(0.1)	2.2	(0.9)
Earnings in equity of subsidiaries	0.0	0.0	0.0	0.0
Net income	(0.2)	1.6	3.7	3.6
Comprehensive income	(0.5)	1.7	3.5	3.8
Consolidating Adjustments
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Net sales	(22.5)	(25.0)	(73.5)	(75.7)
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	(21.1)	(24.1)	(70.3)	(73.5)
Unrealized losses on derivative instruments	0.0	0.0	0.0	0.0
Depreciation and amortization	0.0	0.0	0.0	0.0
Selling, general, administrative, research and development	(0.6)	(0.8)	(1.7)	(2.0)
Net periodic postretirement benefit cost relating to Salaried VEBA	0.0	0.0	0.0	0.0
Gain on removal of Union VEBA net assets	0.0		0.0
Total selling, general, administrative, research and development	(0.6)	(0.8)	(1.7)	(2.0)
Total costs and expenses	(21.7)	(24.9)	(72.0)	(75.5)
Other operating charges, net		0.0		0.0
Operating (loss) income	(0.8)	(0.1)	(1.5)	(0.2)
Other (expense) income:
Interest expense	0.1	0.2	0.3	0.4
Other income (expense), net	(0.1)	(0.2)	(0.3)	(0.4)
(Loss) income before income taxes	(0.8)	(0.1)	(1.5)	(0.2)
Income tax (provision) benefit	2.2	2.8	8.5	10.1
Earnings in equity of subsidiaries	(27.3)	(25.6)	224.7	(87.1)
Net income	(25.9)	(22.9)	231.7	(77.2)
Comprehensive income	$ (26.0)	$ (24.2)	$ 164.3	$ (81.5)