Commitments and Contingencies (Details) (USD $)	1 Months Ended		3 Months Ended			5 Months Ended	12 Months Ended
	Oct. 13, 2010 County	May 31, 2007 Company mi	Mar. 31, 2012 Complaint	Sep. 30, 2011	Mar. 31, 2011	Jun. 06, 2008 Well	Dec. 31, 2009 Entity	May 18, 2010
Loss Contingencies [Line Items]
Number of putative class-action complaints			4
Number of complaints filed			4
Commitments and Contingencies (Textual)
Claims against damages, IDOT/Joliet Road lawsuit								$ 40,000,000
Settlement awarded				24,111,000	25,546,000
Number of wells at issue						244
Number of wells at issue as a result of the discovery to date						13
Number of cases in mass tort action	over 100
Number of counties that cases were filed in the mass tort action	17
Complaints in Florida Antitrust Litigation			2
Number of other parties sued in the Lower Passaic River Clean-Up							300
Number of other companies to perform a Remedial Investigation/Feasibility Study related to the Lower Passaic River Clean-Up lawsuit		70
Number of miles of the River used in the Remedial Investigation/Feasibility Study		17
Range of estimated cost, minimum			900,000,000
Range of estimated cost, maximum			$ 2,300,000,000