Basis of Presentation and Significant Accounting Policies (Details 3) (USD $) In Millions, unless otherwise specified	1 Months Ended		3 Months Ended	12 Months Ended
	Jul. 31, 2009	Apr. 30, 2009	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Mar. 31, 2006
Summary of Significant Accounting Policies (Details)
Purchase price for Beacon Resources, LLC							$ 15.6
Provision for contingent consideration							19.1
Contingent consideration paid and charged to goodwill	3.8	12.7
Impairments of oil and gas properties				15.2	63.8	11.4
Impairment of chemical plant			7.2
Impairment of dive vessel			15.3		15.3
Impairment of joint venture						6.5
Future reimbursement of decommissioning liabilities				7.0	32.5
Reduction in decommissioning liabilities for work performed				94.7	88.2	74.6
Oil and gas balancing receivables			2.6	1.0	2.6
Oil and gas balancing payables			$ 5.4	$ 2.6	$ 5.4