Acquisitions and Divestitures (Components of Discontinued Operations) (Details) (USD $)	12 Months Ended										3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Barnett Shale Field [Member]	Dec. 31, 2013 Discontinued Operations [Member]		Dec. 31, 2012 Discontinued Operations [Member]		Dec. 31, 2011 Discontinued Operations [Member]		Sep. 30, 2012 Discontinued Operations [Member] Pioneer Alaska [Member]	Dec. 31, 2013 Discontinued Operations [Member] Pioneer Alaska [Member]	Dec. 31, 2013 Discontinued Operations [Member] Barnett Shale Field [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Oil and gas	$ 3,155,696,000	$ 2,575,311,000	$ 2,080,215,000		$ 260,503,000		$ 285,542,000		$ 314,124,000
Interest and other	16,961,000	(1,032,000)	29,382,000		38,642,000		29,437,000		45,145,000
Gain on disposition of assets, net	209,021,000	45,898,000	(3,644,000)		8,764,000	[1]	40,735,000	[1]	645,241,000	[1]	12,600,000		8,700,000
Total revenues and other income from discontinued operations					307,909,000		355,714,000		1,004,510,000
Oil and gas production	614,676,000	558,045,000	396,961,000		90,333,000		79,853,000		55,698,000
Production and Ad Valorem Taxes From Discontinued Operations	201,186,000	178,723,000	139,425,000		10,151,000		9,034,000		8,239,000
Depletion, depreciation and amortization	907,077,000	708,270,000	489,579,000		103,787,000	[2]	101,921,000	[2]	130,606,000	[2]
Impairment of oil and gas properties	1,495,242,000	0	354,408,000	532,600,000	729,305,000	[3]	532,589,000	[3]	0	[3]		539,800,000	189,500,000
Exploration Abandonment and Impairment Expense	98,448,000	98,285,000	80,691,000		52,707,000		108,076,000		44,898,000
General and administrative	295,868,000	244,196,000	189,985,000		12,261,000		6,061,000		13,517,000
Accretion of discount on asset retirement obligations	11,862,000	8,677,000	7,506,000		831,000		2,731,000		3,436,000
Interest	183,750,000	204,222,000	181,604,000		0		0		829,000
Other	137,386,000	114,175,000	63,071,000		9,021,000		2,096,000		5,849,000
Costs and expenses, Total	4,281,229,000	2,235,001,000	1,917,179,000		1,008,396,000		842,361,000		263,072,000
Income from discontinued operations before income taxes					(700,487,000)		(486,647,000)		741,438,000
Current	(10,599,000)	(4,259,000)	(6,948,000)		(5,591,000)		(10,387,000)		(46,012,000)
Deferred	222,374,000	(286,229,000)	(181,330,000)		256,473,000		192,824,000		(221,302,000)
Income (loss) from discontinued operations	(449,605,000)	(304,210,000)	474,124,000		(449,605,000)		(304,210,000)		474,124,000
Alaskan Petroleum Production Tax Credit	$ 38,600,000	$ 29,300,000	$ 38,900,000

[1] (a)Primarily comprised of Alaskan Petroleum Production Tax credits on qualifying capital expenditures of $38.6 million, $29.3 million and $38.9 million for the years ended December 31, 2013, 2012 and 2011, respectively.

[2] (b)Represents significant noncash components of discontinued operations.

[3] (c)Represents a noncash impairment charge of $539.8 million on Pioneer Alaska net assets during the year ended December 31, 2013 and noncash impairment charges of $189.5 million and $532.6 million during the years ended December 31, 2013 and 2012, respectively, on the Company's net assets in the Barnett Shale field. See Note D for additional information regarding the noncash impairment charges.