Long-Term Debt (Components Of Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified								12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2008	Dec. 31, 2011 Pioneer Credit Facility [Member]	Dec. 31, 2010 Pioneer Credit Facility [Member]	Dec. 31, 2011 Pioneer Southwest Credit Facility [Member]	Dec. 31, 2010 Pioneer Southwest Credit Facility [Member]	Dec. 31, 2011 5.875% Senior Notes Due 2016 [Member]	Dec. 31, 2010 5.875% Senior Notes Due 2016 [Member]	Dec. 31, 2011 6.65% Senior Notes Due 2017 [Member]	Dec. 31, 2010 6.65% Senior Notes Due 2017 [Member]	Dec. 31, 2011 6.875% Senior Notes Due 2018 [Member]	Dec. 31, 2010 6.875% Senior Notes Due 2018 [Member]	Dec. 31, 2011 7.500% Senior Notes Due 2020 [Member]	Dec. 31, 2010 7.500% Senior Notes Due 2020 [Member]	Dec. 31, 2011 7.20% Senior Notes Due 2028 [Member]	Dec. 31, 2010 7.20% Senior Notes Due 2028 [Member]	Dec. 31, 2011 2.875% Convertible Senior Notes Due 2038 [Member]	Dec. 31, 2010 2.875% Convertible Senior Notes Due 2038 [Member]
Debt Instrument [Line Items]
Outstanding borrowing					$ 49,000	$ 32,000	$ 81,200
Issuance of senior notes								455,385	455,385	485,100	485,100	449,500	449,500	450,000	450,000	250,000	250,000
Convertible debt																		479,930	480,000
Outstanding debt principal balances, gross	2,601,915	2,700,185
Issuance discounts and premiums, net	(71,301)	(96,515)
Net deferred fair value hedge losses	(1,709)	(2,000)
Total long-term debt	$ 2,528,905	$ 2,601,670
Senior notes, interest rate			2.875%					5.875%		6.65%		6.875%		7.50%		7.20%		2.875%
Senior note maturity date								2016		2017		2018		2020		2028		2038