Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	1 Months Ended		3 Months Ended										9 Months Ended	12 Months Ended								6 Months Ended	12 Months Ended			3 Months Ended	12 Months Ended														12 Months Ended		3 Months Ended	6 Months Ended	12 Months Ended					3 Months Ended	12 Months Ended
	Jun. 30, 2010 MBbls	Jan. 31, 2010	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Sep. 30, 2009	Jun. 30, 2009	Sep. 30, 2010	Dec. 31, 2011 MMbls	Dec. 31, 2010		Dec. 31, 2009		Dec. 31, 2008	Aug. 31, 2011	Jan. 31, 2009	Jun. 30, 2009 Cal Dive International Inc [Member]	Dec. 31, 2011 ROVs/Vessels [Member]	Dec. 31, 2010 ROVs/Vessels [Member]	Dec. 31, 2009 ROVs/Vessels [Member]	Dec. 31, 2009 ROV Equipment [Member]	Dec. 31, 2011 Equipment In Australia [Member]	Dec. 31, 2011 Gulf Of Mexico Oil And Gas Properties [Member]	Dec. 31, 2010 Non Producing Oil Field [Member]	Dec. 31, 2011 Producing Oil Field [Member]	Dec. 31, 2010 Producing Oil Field [Member]	Dec. 31, 2009 Producing Oil Field [Member]	Dec. 31, 2011 Other Current Assets [Member]	Dec. 31, 2011 Accrued Liabilities [Member]	Dec. 31, 2011 Shell [Member]	Dec. 31, 2010 Shell [Member]	Dec. 31, 2009 Shell [Member]	Dec. 31, 2010 BP Plc [Member]	Dec. 31, 2011 Crude Oil [Member]	Dec. 31, 2011 Natural Gas [Member]	Dec. 31, 2010 Convertible Preferred Stock [Member]	Dec. 31, 2011 Drilling Pipe Inventory [Member]	Dec. 31, 2011 United Kingdom [Member]	Jun. 30, 2010 United Kingdom [Member]	Dec. 31, 2011 United Kingdom [Member]	Dec. 31, 2010 United Kingdom [Member]	Dec. 31, 2009 United Kingdom [Member]	Dec. 31, 2009 Gulf Of Mexico Oil And Gas Properties [Member]	Dec. 31, 2011 3.25% Convertible Senior Notes [Member]	Jun. 30, 2009 Hurricane [Member]	Dec. 31, 2009 Hurricane [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership in CDI reduced														50.00%
Restricted cash			$ 33,741,000				$ 35,339,000							$ 33,741,000	$ 35,339,000
Accruals for capital expenditures														26,100,000	21,900,000		48,900,000
Inventory			18,066,000				25,333,000							18,066,000	25,333,000																											4,600,000
Number of drilling pipes sold, actual			2,500,000											2,500,000
Charges to reduce inventory to its lower cost														2,100,000	0		1,800,000
Repair and maintenance expenses														40,100,000	35,000,000		35,600,000
Capitalized software costs			18,100,000				17,800,000							18,100,000	17,800,000
Amortization of software costs														2,600,000	2,600,000		2,600,000
Impairment of long-lived assets held-for-use																							0	0	0	1,300,000	6,600,000
Assets classified as held for sale			0				0							0	0
Oil and gas impairments			107,500,000	2,400,000	22,700,000	0	9,200,000	900,000	159,900,000	11,100,000	64,600,000	48,200,000		132,603,000	181,083,000		120,550,000											21,700,000	3,500,000	90,900,000	172,600,000	72,400,000												5,000,000	20,000,000	5,000,000				43,800,000	51,500,000
Impairment of unproved properties														8,334,000	6,394,000		20,130,000
Dry hole expense and other														(70,000)	(424,000)		1,237,000
Interest expense capitalized														1,300,000	12,500,000		48,100,000
Goodwill and other indefinite-lived intangible impairments							16,700,000								16,743,000	[1]
Goodwill			62,215,000				62,494,000							62,215,000	62,494,000		78,643,000	[2]	704,300,000
Intangible assets other than goodwill			1,600,000											1,600,000
Intangible asset, net of accumulated amortization			531,000				636,000							531,000	636,000
Amortization expenses for intangible assets														100,000	100,000		2,400,000
Amortization expense 2012														100,000
Amortization expense 2013														100,000
Amortization expense 2014														100,000
Amortization expense 2015														100,000
Amortization expense 2016														100,000
Deferred drydock costs, net			5,381,000				11,086,000							5,381,000	11,086,000
Drydock amortization expense														7,600,000	6,900,000		16,400,000					9,300,000
Cash paid for loss on contracts									5,500,000										7,200,000
Previously accrued loss						200,000							12,000,000		30,000,000		3,700,000
Net imbalance			900,000											900,000																			5,100,000	4,200,000
Unrealized (loss) gain on translation adjustment														(1,000,000)	(10,000,000)
Foreign currency gains (losses)														(1,600,000)	1,700,000		2,200,000
Commodity derivative contracts qualified for hedge accounting (MMbls)	480
Commodity derivative, net liability			19,800,000				24,400,000							19,800,000	24,400,000
Unrealized gains (losses) on commodity derivatives														28,700,000	(6,500,000)		(19,100,000)
Unrealized gains (losses) on commodity derivatives, tax														15,500,000	(3,500,000)		(10,300,000)
Gains (losses) reclassified from accumulated other comprehensive income (loss) to oil and gas revenues														(21,700,000)	25,600,000		17,000,000
Gain (Loss) on Sale of Commodity Contracts															1,088,000		89,485,000
Forward sales contract volume																																							3,800,000	17,000,000,000
Costless collar financial derivative contract														0.1
Floor price			100											100
Ceiling price			120											120
Interest rate swap maximum term in years		two
Interest rate swaps notional amount		200,000,000																		200,000,000
Interest swap contracts assets			100,000											100,000
Interest swap contracts liability			1,900,000											1,900,000
Foreign currency forwards net			100,000				200,000							100,000	200,000
Recorded gains (losses) foreign currency forwards														200,000	(2,600,000)		3,300,000
Preferred stock beneficial conversion charges																	53,439,000
Dividends and related costs														40,000	114,000		54,187,000																								100,000
Revenues from major customers representing 10% or more of revenues																																			49.00%	29.00%	19.00%	17.00%
Subsea services to customers														75
Aggregate fair value of properties			60,600,000				91,500,000							60,600,000	91,500,000																																	36,200,000
Increase in expected asset retirement cost			28,200,000											20,000,000																													15,900,000
Net book value of the affected fields			2,331,327,000				2,527,080,000							2,331,327,000	2,527,080,000		2,863,706,000																										281,430,000		281,430,000	275,012,000	284,637,000
Unamortized debt discount			$ 9,555,000											$ 9,555,000							$ 60,200,000
Conversion price			$ 38.56											$ 38.56																																			$ 32.14
Debt instrument stated percentage																																																	3.25%

[1] Amount reflects full write off of goodwill associated with our WOSEA operations.

[2] Prior to 2009, we fully impaired our oil and gas related goodwill ($704.3 million) as well as the $8.3 million of goodwill associated with our former reservoir consulting business.