Inventories (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Inventory [Line Items]
Inventories at FIFO, net of reserves	$ 622.8		$ 622.8		$ 524.6
Less: LIFO reserve	(127.2)		(127.2)		(117.2)
Total inventories at LIFO, net of reserves	495.6		495.6		407.4
LIFO expense	3.7	$ 3.3	10.0	$ 9.2
United States
Inventory [Line Items]
Less: LIFO reserve	$ (127.2)		$ (127.2)		$ (117.2)