Summary of Significant Accounting Policies - Components of Inventories (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Raw materials	$ 261.9us-gaap_InventoryRawMaterials	$ 212.0us-gaap_InventoryRawMaterials
Work in process	11.3us-gaap_InventoryWorkInProcess	13.9us-gaap_InventoryWorkInProcess
Finished goods	216.3us-gaap_InventoryFinishedGoods	210.0us-gaap_InventoryFinishedGoods
Supplies and materials	175.4us-gaap_OtherInventorySupplies	158.4us-gaap_OtherInventorySupplies
Inventories	$ 664.9us-gaap_InventoryNet	$ 594.3us-gaap_InventoryNet

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Amount before valuation and LIFO reserves of completed merchandise or goods expected to be sold within one year or operating cycle, if longer.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount before valuation and LIFO reserves of raw materials expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount before valuation and LIFO reserves of merchandise or goods in the production process expected to be completed within one year or operating cycle, if longer.

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Amount before valuation and LIFO reserves of other supplies used within the manufacturing or production process expected to be consumed within one year or operating cycle, if longer.

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