Inventories (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Inventory Disclosure [Abstract]
Inventories at FIFO, net of reserves	$ 414.6		$ 533.1
Less: LIFO reserve	(117.7)us-gaap_InventoryLIFOReserve		(115.3)us-gaap_InventoryLIFOReserve
Total inventories at LIFO, net of reserves	296.9us-gaap_InventoryNet		417.8us-gaap_InventoryNet
LIFO expense	$ 2.4	$ 2.8

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.6(a))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 330

-SubTopic 10

-Section 35

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6386567&loc=d3e3927-108312

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6676-107765

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant