Basis Of Presentation (Narrative) (Details) (USD $)	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Percentage of divest of subsidiaries capital stock				100.00%
Allowance for Doubtful Accounts, Premiums and Other Receivables	$ 1,414,000	$ 3,535,000		$ 1,414,000		$ 3,674,000
Materials and supplies inventories	247,900,000			247,900,000		183,400,000
Commodities	4,100,000			4,100,000		3,900,000
Net materials and supplies inventories reserves	2,500,000			2,500,000		3,600,000
Inventory value classified as other noncurrent assets	17,900,000			17,900,000		13,700,000
Basis points added to variable interest rate				250
Noncontrolling interest in net assets subsidiaries	101,032,000			101,032,000		105,442,000
Net income attributable to the noncontrolling interests	20,123,000		21,113,000	15,333,000	36,465,000
Allocated stock-based compensation expense	13,800,000		10,500,000	26,400,000	20,600,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		three
Restricted stock awards unvested shares at balance sheet date				536,775		825,796
Restricted stock awards liability				21,600,000
Unrecognized compensation expense	93,100,000			93,100,000
Restricted Stock Equity Awards [Member]
Amount of liabilities attributable to liability awards included in accounts payable				3,900,000
Limited Partner Interest [Member] | Pioneer Southwest [Member]
Partnerships interest of oil and gas	61.90%			61.90%
General Partner Interest [Member] | Subsidiaries [Member]
Partnerships interest of oil and gas	0.10%			0.10%
EFS Midstream [Member]
Percent of interest owned				50.10%
Pioneer Southwest [Member]
Net income attributable to the noncontrolling interests	20,100,000		21,100,000	15,300,000	36,500,000
Tunisian Subsidiaries [Member]
Inventories classified as discontinued operations held for sale						13,600,000
BOEMRE [Member]
Interest and other				$ 2,000,000	$ 35,300,000