Inventories (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Inventory Disclosure [Abstract]
Inventories at FIFO, net of reserves	$ 412.2		$ 412.2		$ 488.2
Less: LIFO reserve	(106.1)		(106.1)		(99.0)
Total inventories at LIFO, net of reserves	306.1		306.1		389.2
LIFO expense	$ 4.3	$ 3.7	$ 7.1	$ 6.6