Guarantor and Non-Guarantor Financial Statements, Balance Sheets (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 220.9	$ 177.7	$ 185.6	$ 169.5
Short-term investments	30.0	114.0
Receivables:
Trade, less allowance for doubtful receivables	149.7	129.3
Intercompany receivables	0	0
Other	8.8	10.9
Inventories	218.0	214.7
Prepaid expenses and other current assets	195.8	178.6
Total current assets	823.2	825.2
Investments in and advances to subsidiaries	0	0
Property, plant and equipment – net	458.1	454.9
Long-term intercompany receivables	0	0
Net assets of Union VEBA	0	340.1
Deferred tax assets — net	161.7	30.9
Intangible assets – net	31.7	32.1
Goodwill	37.2	37.2
Other assets	23.0	23.3
Total	1,534.9	1,743.7
Current liabilities:
Accounts payable	83.1	81.4
Intercompany payable	0	0
Accrued salaries, wages and related expenses	33.6	39.6
Other accrued liabilities	157.2	132.8
Current portion of long-term debt	175.0	172.5
Short-term capital leases	0	0.1
Total current liabilities	448.9	426.4
Net liabilities of Salaried VEBA	16.8	17.2
Deferred tax liabilities	0.8	0.9
Long-term intercompany payable	0	0
Long-term liabilities	89.1	58.3
Long-term debt	225.0	225.0
Total liabilities	780.6	727.8
Total stockholders’ equity	754.3	1,015.9
Total	1,534.9	1,743.7
Parent
Current assets:
Cash and cash equivalents	0	0	5.0	5.0
Short-term investments	0	0
Receivables:
Trade, less allowance for doubtful receivables	0	0
Intercompany receivables	204.2	204.2
Other	0	0
Inventories	0	0
Prepaid expenses and other current assets	95.0	85.1
Total current assets	299.2	289.3
Investments in and advances to subsidiaries	997.5	1,209.2
Property, plant and equipment – net	0	0
Long-term intercompany receivables	0	0
Net assets of Union VEBA		0
Deferred tax assets — net	0	0
Intangible assets – net	0	0
Goodwill	0	0
Other assets	4.2	4.4
Total	1,300.9	1,502.9
Current liabilities:
Accounts payable	2.3	1.3
Intercompany payable	39.3	0
Accrued salaries, wages and related expenses	0	0
Other accrued liabilities	105.0	88.2
Current portion of long-term debt	175.0	172.5
Short-term capital leases		0
Total current liabilities	321.6	262.0
Net liabilities of Salaried VEBA	0	0
Deferred tax liabilities	0	0
Long-term intercompany payable	0	0
Long-term liabilities	0	0
Long-term debt	225.0	225.0
Total liabilities	546.6	487.0
Total stockholders’ equity	754.3	1,015.9
Total	1,300.9	1,502.9
Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	218.9	175.3	174.3	157.7
Short-term investments	30.0	114.0
Receivables:
Trade, less allowance for doubtful receivables	145.2	126.1
Intercompany receivables	43.5	4.0
Other	4.3	5.6
Inventories	213.3	208.0
Prepaid expenses and other current assets	100.4	93.1
Total current assets	755.6	726.1
Investments in and advances to subsidiaries	33.9	32.5
Property, plant and equipment – net	436.8	437.4
Long-term intercompany receivables	0	0
Net assets of Union VEBA		340.1
Deferred tax assets — net	154.6	23.8
Intangible assets – net	31.7	32.1
Goodwill	37.2	37.2
Other assets	18.7	18.8
Total	1,468.5	1,648.0
Current liabilities:
Accounts payable	74.8	73.8
Intercompany payable	211.3	221.3
Accrued salaries, wages and related expenses	30.6	36.5
Other accrued liabilities	51.9	43.8
Current portion of long-term debt	0	0
Short-term capital leases		0.1
Total current liabilities	368.6	375.5
Net liabilities of Salaried VEBA	16.8	17.2
Deferred tax liabilities	0	0
Long-term intercompany payable	14.0	15.9
Long-term liabilities	81.5	50.3
Long-term debt	0	0
Total liabilities	480.9	458.9
Total stockholders’ equity	987.6	1,189.1
Total	1,468.5	1,648.0
Non-Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	2.0	2.4	6.3	6.8
Short-term investments	0	0
Receivables:
Trade, less allowance for doubtful receivables	4.5	3.2
Intercompany receivables	1.0	0.9
Other	4.5	5.3
Inventories	5.7	7.6
Prepaid expenses and other current assets	0.4	0.4
Total current assets	18.1	19.8
Investments in and advances to subsidiaries	0	0
Property, plant and equipment – net	21.3	17.5
Long-term intercompany receivables	14.0	15.9
Net assets of Union VEBA		0
Deferred tax assets — net	0	0
Intangible assets – net	0	0
Goodwill	0	0
Other assets	0.1	0.1
Total	53.5	53.3
Current liabilities:
Accounts payable	6.0	6.3
Intercompany payable	3.5	3.3
Accrued salaries, wages and related expenses	3.0	3.1
Other accrued liabilities	0.3	0.8
Current portion of long-term debt	0	0
Short-term capital leases		0
Total current liabilities	12.8	13.5
Net liabilities of Salaried VEBA	0	0
Deferred tax liabilities	0.8	0.9
Long-term intercompany payable	0	0
Long-term liabilities	7.6	8.0
Long-term debt	0	0
Total liabilities	21.2	22.4
Total stockholders’ equity	32.3	30.9
Total	53.5	53.3
Consolidating Adjustments
Current assets:
Cash and cash equivalents	0	0	0	0
Short-term investments	0	0
Receivables:
Trade, less allowance for doubtful receivables	0	0
Intercompany receivables	(248.7)	(209.1)
Other	0	0
Inventories	(1.0)	(0.9)
Prepaid expenses and other current assets	0	0
Total current assets	(249.7)	(210.0)
Investments in and advances to subsidiaries	(1,031.4)	(1,241.7)
Property, plant and equipment – net	0	0
Long-term intercompany receivables	(14.0)	(15.9)
Net assets of Union VEBA		0
Deferred tax assets — net	7.1	7.1
Intangible assets – net	0	0
Goodwill	0	0
Other assets	0	0
Total	(1,288.0)	(1,460.5)
Current liabilities:
Accounts payable	0	0
Intercompany payable	(254.1)	(224.6)
Accrued salaries, wages and related expenses	0	0
Other accrued liabilities	0	0
Current portion of long-term debt	0	0
Short-term capital leases		0
Total current liabilities	(254.1)	(224.6)
Net liabilities of Salaried VEBA	0	0
Deferred tax liabilities	0	0
Long-term intercompany payable	(14.0)	(15.9)
Long-term liabilities	0	0
Long-term debt	0	0
Total liabilities	(268.1)	(240.5)
Total stockholders’ equity	(1,019.9)	(1,220.0)
Total	$ (1,288.0)	$ (1,460.5)