Inventories (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Inventory Disclosure [Abstract]
Inventories at FIFO, net of reserves	$ 445.9		$ 445.9		$ 456.7
Less: LIFO reserve	(99.1)		(99.1)		(90.3)
Total inventories at LIFO, net of reserves	346.8		346.8		366.4
LIFO expense	$ 2.2	$ 3.8	$ 8.8	$ 11.0