Summary Of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Summary Of Significant Accounting Policies [Abstract]

Allowance For Doubtful Accounts

	Year Ended December 31,
	2011			2010
	(in thousands)
Beginning allowance for doubtful accounts balance	$	3,674		$	14,299
Amount credited to costs and expenses, net		(1,693	)		(442	)
Other net decreases		(835	)		(10,183	)
Ending allowance for doubtful accounts balance	$	1,146		$	3,674

Effects Of Changes In The Company's Ownership Interest

	Year Ended December 31,
	2011		2010		2009
	(in thousands)
Net income (loss) attributable to common stockholders	$	834,489	$	605,208	$	(52,106	)
Transfers from the noncontrolling interest in consolidated subsidiaries:
Increase in additional paid in capital for Pioneer Southwest offering of 3.1 million common units issued on November 16, 2009		—		—		33,388
Increase in additional paid in capital for the sale of 1.8 million Pioneer Southwest common units on December 12, 2011, net of tax of $15.4 million		26,915		—		—
Increase in additional paid in capital for Pioneer Southwest offering of 2.6 million common units issued on December 12, 2011, net of tax of $23.7 million		8,104		—		—
Net transfers from noncontrolling interest		35,019		—		33,388
Net income (loss) attributable to common stockholders and transfers from noncontrolling interest	$	869,508	$	605,208	$	(18,718	)

Oil Entitlement Liabilities And Gas Entitlement Assets And Liabilities

	December 31,
	2011				2010
	Amount		Volume		Amount		Volume
	(dollars in millions)
Oil entitlement liabilities (volumes in MBbls)	$	—		—	$	1.2		13
Gas entitlement assets (volumes in MMcf)	$	7.6		3,024	$	7.6		3,015
Gas entitlement liabilities (volumes in MMcf)	$	2.6		650	$	1.6		439