Property, Plant and Equipment - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Property Plant And Equipment [Line Items]
Depreciation expense	$ 86.4	$ 92.6	$ 174.9	$ 188.0
Book value of assets held for sale	$ 24.1		$ 24.1		$ 19.2