Discontinued Operations (Components Of Discontinued Operations) (Details) (USD $)	12 Months Ended						1 Months Ended	3 Months Ended					12 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009		Feb. 28, 2011 Pioneer Tunisia [Member]	Sep. 30, 2010 Gulf Of Mexico Shelf Properties [Member]	Mar. 31, 2011 Gulf Of Mexico Shelf Properties [Member] Pioneer Tunisia [Member]	Mar. 31, 2011 Gulf Of Mexico Shelf Properties [Member] BOEMRE [Member]	Jun. 30, 2010 Gulf Of Mexico Shelf Properties [Member] BOEMRE [Member]	Dec. 31, 2009 Gulf Of Mexico Shelf Properties [Member] BOEMRE [Member]	Dec. 31, 2010 Gulf Of Mexico Shelf Properties [Member] BOEMRE [Member]	Jun. 30, 2010 Canadian [Member]	Dec. 31, 2010 Argentina [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Oil and gas	$ 100,275,000		$ 236,343,000		$ 221,279,000
Interest and other	6,193,000	[1]	49,076,000	[1]	120,062,000	[1]							35,300,000
Gain on disposition of assets, net	645,241,000	[2]	36,000	[2]	17,491,000	[2]
Gains from the disposition of discontinued operations	645,200,000		17,500,000
Total revenues and other income from discontinued operations	751,709,000		285,455,000		358,832,000
Oil and gas production	5,519,000		14,754,000		39,621,000
Production and ad valorem taxes					(27,000)
Depletion, depreciation and amortization	41,916,000	[2]	98,495,000	[2]	91,273,000	[2]
Exploration and abandonments	4,268,000	[2]	15,908,000	[2]	19,240,000	[2]
General and administrative	10,286,000		5,697,000		9,647,000
Accretion of discount on asset retirement obligations	2,686,000	[2]	2,923,000	[2]	3,517,000	[2]
Interest	773,000				8,000
Other	5,159,000		13,898,000		10,310,000
Total costs and expenses from discontinued operations	70,607,000		151,675,000		173,589,000
Income from discontinued operations before income taxes	681,102,000		133,780,000		185,243,000
Current	(43,897,000)		(25,486,000)		(20,057,000)
Deferred	(214,053,000)		25,756,000		(65,470,000)
Income from discontinued operations	423,152,000		134,050,000		99,716,000
Cash proceeds from sale of subsidiaries, net							853,600,000
Recovery of excess royalties												119,300,000
Interest and other	101,960,000		56,972,000		101,589,000				2,800,000	2,000,000	35,300,000
Proceeds from legal settlements								2,800,000
Sales tax refund														$ 2,100,000	$ 3,800,000

[1] Primarily comprised of (i) $119.3 million receivable from the BOEMRE recorded in the fourth quarter of 2009 for the recovery of excess royalties paid by the Company on qualifying deepwater leases in the Gulf of Mexico, (ii) $35.3 million of associated interest on the aforementioned excess royalty payments received from BOEMRE during the second quarter of 2010, (iii) $2.8 million of legal settlements paid to the Company during the third quarter of 2010 on Gulf of Mexico discontinued operations sold during 2006, (iv) $2.1 million of Canadian sales tax refunds paid to the Company during the second quarter of 2010 attributable Canadian discontinued operations sold during 2007, (v) $3.8 million of Argentine value added tax contingency charge reversals recorded during 2010 on Argentine discontinued operations sold during 2006, (vi) $2.0 million of interest received during the first quarter of 2011 associated with the 2010 recovery of excess royalties paid by the Company on qualifying deepwater leases in the Gulf of Mexico and (vii) $2.8 million of interest income associated with Pioneer Tunisia operations recorded during the first quarter of 2011.

[2] Represents the significant noncash components of discontinued operations.