Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 LegalMatter	Dec. 31, 2011
Loss Contingencies [Line Items]
Number Of Lawsuits	1,900
Number Of Claims In Lawsuit	2,300
Liability For claims and contingencies	$ 234.6	$ 0.6
Liability reserve for insurance claims	157.4	0
Environmental Reserve	35.9	1.5
Outstanding Value Of Letters Of Credit	$ 493.2	$ 136.2