Property, Plant and Equipment - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Proceeds from disposals			$ 34.2
Gain on sale of property			7.6
Depreciation expense	89.3	103.8	277.3	316.1
Book value of assets held for sale	$ 21.9		$ 21.9		$ 20.2