Financial Information for Subsidiary and Guarantor Parent (B.S.) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
ASSETS
Cash and cash equivalents	$ 188.4	$ 149.8	$ 197.5	$ 269.5
Accounts receivable, net	454.0	400.3
Intercompany notes receivable	0.0	0.0
Inventories, net	1,078.9	1,271.6
Prepaid expenses and other current assets	40.8	45.9
Total current assets	1,762.1	1,867.6
Property, plant and equipment, net	2,514.4	2,928.2
Goodwill	644.4	651.4
Intercompany notes receivable	0.0	0.0
Investment in subsidiaries	0.0	0.0
Other assets	271.4	304.5
Total assets	5,192.3	5,751.7
LIABILITIES AND EQUITY
Accounts payable	285.2	380.8
Accrued liabilities	310.9	301.8
Intercompany notes payable	0.0	0.0
Short-term debt and current portion of long-term debt	5.4	3.9
Total current liabilities	601.5	686.5
Long-term debt	1,870.4	1,491.8
Intercompany notes payable	0.0	0.0
Accrued postretirement benefits	311.6	359.2
Pension liabilities	708.6	833.8
Deferred income taxes	51.3	75.6
Other long-term liabilities	86.2	108.3
Total liabilities	3,629.6	3,555.2
Redeemable noncontrolling interest	0.0	12.1
Total stockholders’ equity	1,562.7	2,184.4	$ 2,505.5	$ 2,709.3
Total Liabilities and Equity	5,192.3	5,751.7
Reportable Legal Entities \| Parent Company
ASSETS
Cash and cash equivalents	2.3	0.4
Accounts receivable, net	0.1	0.1
Intercompany notes receivable	0.0	0.0
Inventories, net	0.0	0.0
Prepaid expenses and other current assets	3.3	9.3
Total current assets	5.7	9.8
Property, plant and equipment, net	1.5	2.2
Goodwill	0.0	0.0
Intercompany notes receivable	0.0	0.0
Investment in subsidiaries	5,363.3	5,742.5
Other assets	22.1	13.4
Total assets	5,392.6	5,767.9
LIABILITIES AND EQUITY
Accounts payable	3.5	4.8
Accrued liabilities	35.6	42.1
Intercompany notes payable	1,442.1	1,325.4
Short-term debt and current portion of long-term debt	0.7	0.7
Total current liabilities	1,481.9	1,373.0
Long-term debt	1,620.9	1,341.7
Intercompany notes payable	0.0	0.0
Accrued postretirement benefits	0.0	0.0
Pension liabilities	658.9	778.0
Deferred income taxes	51.3	75.6
Other long-term liabilities	16.9	15.2
Total liabilities	3,829.9	3,583.5
Redeemable noncontrolling interest		0.0
Total stockholders’ equity	1,562.7	2,184.4
Total Liabilities and Equity	5,392.6	5,767.9
Reportable Legal Entities \| Subsidiary
ASSETS
Cash and cash equivalents	4.3	2.8
Accounts receivable, net	115.7	100.3
Intercompany notes receivable	0.0	0.0
Inventories, net	137.6	239.9
Prepaid expenses and other current assets	4.9	3.8
Total current assets	262.5	346.8
Property, plant and equipment, net	1,587.7	1,559.9
Goodwill	0.0	0.0
Intercompany notes receivable	0.0	0.0
Investment in subsidiaries	37.7	37.7
Other assets	26.1	23.0
Total assets	1,914.0	1,967.4
LIABILITIES AND EQUITY
Accounts payable	123.9	171.1
Accrued liabilities	91.0	74.0
Intercompany notes payable	1,513.7	1,276.1
Short-term debt and current portion of long-term debt	0.3	0.1
Total current liabilities	1,728.9	1,521.3
Long-term debt	149.9	149.7
Intercompany notes payable	200.0	200.0
Accrued postretirement benefits	245.1	280.0
Pension liabilities	4.7	5.2
Deferred income taxes	0.0	0.0
Other long-term liabilities	18.8	20.7
Total liabilities	2,347.4	2,176.9
Redeemable noncontrolling interest		0.0
Total stockholders’ equity	(433.4)	(209.5)
Total Liabilities and Equity	1,914.0	1,967.4
Reportable Legal Entities \| NonGuarantor Subsidiaries
ASSETS
Cash and cash equivalents	181.8	146.6
Accounts receivable, net	338.2	299.9
Intercompany notes receivable	2,955.8	2,601.5
Inventories, net	941.3	1,031.7
Prepaid expenses and other current assets	32.6	32.8
Total current assets	4,449.7	4,112.5
Property, plant and equipment, net	925.2	1,366.1
Goodwill	644.4	651.4
Intercompany notes receivable	200.0	200.0
Investment in subsidiaries	0.0	0.0
Other assets	223.2	268.1
Total assets	6,442.5	6,598.1
LIABILITIES AND EQUITY
Accounts payable	157.8	204.9
Accrued liabilities	184.3	185.7
Intercompany notes payable	0.0	0.0
Short-term debt and current portion of long-term debt	4.4	3.1
Total current liabilities	346.5	393.7
Long-term debt	99.6	0.4
Intercompany notes payable	0.0	0.0
Accrued postretirement benefits	66.5	79.2
Pension liabilities	45.0	50.6
Deferred income taxes	0.0	0.0
Other long-term liabilities	50.5	72.4
Total liabilities	608.1	596.3
Redeemable noncontrolling interest		12.1
Total stockholders’ equity	5,834.4	5,989.7
Total Liabilities and Equity	6,442.5	6,598.1
Eliminations
ASSETS
Cash and cash equivalents	0.0	0.0
Accounts receivable, net	0.0	0.0
Intercompany notes receivable	(2,955.8)	(2,601.5)
Inventories, net	0.0	0.0
Prepaid expenses and other current assets	0.0	0.0
Total current assets	(2,955.8)	(2,601.5)
Property, plant and equipment, net	0.0	0.0
Goodwill	0.0	0.0
Intercompany notes receivable	(200.0)	(200.0)
Investment in subsidiaries	(5,401.0)	(5,780.2)
Other assets	0.0	0.0
Total assets	(8,556.8)	(8,581.7)
LIABILITIES AND EQUITY
Accounts payable	0.0	0.0
Accrued liabilities	0.0	0.0
Intercompany notes payable	(2,955.8)	(2,601.5)
Short-term debt and current portion of long-term debt	0.0	0.0
Total current liabilities	(2,955.8)	(2,601.5)
Long-term debt	0.0	0.0
Intercompany notes payable	(200.0)	(200.0)
Accrued postretirement benefits	0.0	0.0
Pension liabilities	0.0	0.0
Deferred income taxes	0.0	0.0
Other long-term liabilities	0.0	0.0
Total liabilities	(3,155.8)	(2,801.5)
Redeemable noncontrolling interest		0.0
Total stockholders’ equity	(5,401.0)	(5,780.2)
Total Liabilities and Equity	$ (8,556.8)	$ (8,581.7)

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.