Income Taxes (Schedule Of Income Tax (Provision) Benefit Allocation) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Taxes [Abstract]
Income from continuing operations	$ (197,644)	$ (269,627)	$ 83,195
Income from discontinued operations	(257,950)	270	(85,527)
Changes in goodwill - tax benefits related to stock-based compensation	40	453	124
Net deferred hedge gains	8,407	23,648	50,059
Tax benefits related to stock-based compensation	31,087	(153)	1
Tax on Pioneer Southwest common units sold by the Company on December 12, 2011	$ (15,381)

Tax effect allocated to a disposal group that is classified as a component of the entity reported as a separate component of income before extraordinary items. Includes the tax effects of the following: income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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+ Details

- Definition

The tax effects of employee stock option transactions that are recognized differently for financial reporting and tax purposes, occurring during the period and charged or credited directly to shareholders' equity.

+ References+ Details

- Definition

The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

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- Definition

Tax effect on the change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

+ References+ Details