Guarantor and Non-Guarantor Financial Statements, Balance Sheets (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 54.3	$ 177.7	$ 174.2	$ 169.5
Short-term investments	30.0	114.0
Receivables:
Trade receivables — net	138.6	129.3
Intercompany receivables	0.0	0.0
Other	5.9	10.9
Inventories	217.3	214.7
Prepaid expenses and other current assets	100.4	178.6
Total current assets	546.5	825.2
Investments in and advances to subsidiaries	0.0	0.0
Property, plant and equipment – net	464.5	454.9
Long-term intercompany receivables	0.0	0.0
Net assets of Union VEBA	0.0	340.1
Deferred tax assets — net	148.7	30.9
Intangible assets – net	31.3	32.1
Goodwill	37.2	37.2
Other assets	23.1	23.3
Total	1,251.3	1,743.7
Current liabilities:
Accounts payable	77.4	81.4
Intercompany payable	0.0	0.0
Accrued salaries, wages and related expenses	34.4	39.6
Other accrued liabilities	51.6	132.8
Current portion of long-term debt	0.0	172.5
Short-term capital leases	0.1	0.1
Total current liabilities	163.5	426.4
Net liabilities of Salaried VEBA	16.4	17.2
Deferred tax liabilities	0.8	0.9
Long-term intercompany payable	0.0	0.0
Long-term liabilities	86.8	58.3
Long-term debt	225.0	225.0
Total liabilities	492.5	727.8
Total stockholders’ equity	758.8	1,015.9
Total	1,251.3	1,743.7
Parent
Current assets:
Cash and cash equivalents	0.0	0.0	5.0	5.0
Short-term investments	0.0	0.0
Receivables:
Trade receivables — net	0.0	0.0
Intercompany receivables	29.2	204.2
Other	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses and other current assets	0.2	85.1
Total current assets	29.4	289.3
Investments in and advances to subsidiaries	1,026.8	1,209.2
Property, plant and equipment – net	0.0	0.0
Long-term intercompany receivables	0.0	0.0
Net assets of Union VEBA		0.0
Deferred tax assets — net	0.0	0.0
Intangible assets – net	0.0	0.0
Goodwill	0.0	0.0
Other assets	4.0	4.4
Total	1,060.2	1,502.9
Current liabilities:
Accounts payable	0.6	1.3
Intercompany payable	74.3	0.0
Accrued salaries, wages and related expenses	0.0	0.0
Other accrued liabilities	1.5	88.2
Current portion of long-term debt		172.5
Short-term capital leases	0.0	0.0
Total current liabilities	76.4	262.0
Net liabilities of Salaried VEBA	0.0	0.0
Deferred tax liabilities	0.0	0.0
Long-term intercompany payable	0.0	0.0
Long-term liabilities	0.0	0.0
Long-term debt	225.0	225.0
Total liabilities	301.4	487.0
Total stockholders’ equity	758.8	1,015.9
Total	1,060.2	1,502.9
Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	49.8	175.3	164.7	157.7
Short-term investments	30.0	114.0
Receivables:
Trade receivables — net	134.7	126.1
Intercompany receivables	78.7	4.0
Other	2.6	5.6
Inventories	212.8	208.0
Prepaid expenses and other current assets	99.8	93.1
Total current assets	608.4	726.1
Investments in and advances to subsidiaries	33.6	32.5
Property, plant and equipment – net	439.5	437.4
Long-term intercompany receivables	0.0	0.0
Net assets of Union VEBA		340.1
Deferred tax assets — net	141.6	23.8
Intangible assets – net	31.3	32.1
Goodwill	37.2	37.2
Other assets	19.0	18.8
Total	1,310.6	1,648.0
Current liabilities:
Accounts payable	67.5	73.8
Intercompany payable	39.5	221.3
Accrued salaries, wages and related expenses	31.5	36.5
Other accrued liabilities	50.1	43.8
Current portion of long-term debt		0.0
Short-term capital leases	0.1	0.1
Total current liabilities	188.7	375.5
Net liabilities of Salaried VEBA	16.4	17.2
Deferred tax liabilities	0.0	0.0
Long-term intercompany payable	10.2	15.9
Long-term liabilities	80.9	50.3
Long-term debt	0.0	0.0
Total liabilities	296.2	458.9
Total stockholders’ equity	1,014.4	1,189.1
Total	1,310.6	1,648.0
Non-Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	4.5	2.4	4.5	6.8
Short-term investments	0.0	0.0
Receivables:
Trade receivables — net	3.9	3.2
Intercompany receivables	1.8	0.9
Other	3.3	5.3
Inventories	6.1	7.6
Prepaid expenses and other current assets	0.4	0.4
Total current assets	20.0	19.8
Investments in and advances to subsidiaries	0.0	0.0
Property, plant and equipment – net	25.0	17.5
Long-term intercompany receivables	10.2	15.9
Net assets of Union VEBA		0.0
Deferred tax assets — net	0.0	0.0
Intangible assets – net	0.0	0.0
Goodwill	0.0	0.0
Other assets	0.1	0.1
Total	55.3	53.3
Current liabilities:
Accounts payable	9.3	6.3
Intercompany payable	3.7	3.3
Accrued salaries, wages and related expenses	2.9	3.1
Other accrued liabilities	0.0	0.8
Current portion of long-term debt		0.0
Short-term capital leases	0.0	0.0
Total current liabilities	15.9	13.5
Net liabilities of Salaried VEBA	0.0	0.0
Deferred tax liabilities	0.8	0.9
Long-term intercompany payable	0.0	0.0
Long-term liabilities	5.9	8.0
Long-term debt	0.0	0.0
Total liabilities	22.6	22.4
Total stockholders’ equity	32.7	30.9
Total	55.3	53.3
Consolidating Adjustments
Current assets:
Cash and cash equivalents	0.0	0.0	$ 0.0	$ 0.0
Short-term investments	0.0	0.0
Receivables:
Trade receivables — net	0.0	0.0
Intercompany receivables	(109.7)	(209.1)
Other	0.0	0.0
Inventories	(1.6)	(0.9)
Prepaid expenses and other current assets	0.0	0.0
Total current assets	(111.3)	(210.0)
Investments in and advances to subsidiaries	(1,060.4)	(1,241.7)
Property, plant and equipment – net	0.0	0.0
Long-term intercompany receivables	(10.2)	(15.9)
Net assets of Union VEBA		0.0
Deferred tax assets — net	7.1	7.1
Intangible assets – net	0.0	0.0
Goodwill	0.0	0.0
Other assets	0.0	0.0
Total	(1,174.8)	(1,460.5)
Current liabilities:
Accounts payable	0.0	0.0
Intercompany payable	(117.5)	(224.6)
Accrued salaries, wages and related expenses	0.0	0.0
Other accrued liabilities	0.0	0.0
Current portion of long-term debt		0.0
Short-term capital leases	0.0	0.0
Total current liabilities	(117.5)	(224.6)
Net liabilities of Salaried VEBA	0.0	0.0
Deferred tax liabilities	0.0	0.0
Long-term intercompany payable	(10.2)	(15.9)
Long-term liabilities	0.0	0.0
Long-term debt	0.0	0.0
Total liabilities	(127.7)	(240.5)
Total stockholders’ equity	(1,047.1)	(1,220.0)
Total	$ (1,174.8)	$ (1,460.5)