Summary Of Significant Accounting Policies (Changes of Ownership Interest) (Details) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net Income (loss) attributable to common stockholders	$ (838,414,000)	$ 192,285,000	$ 834,489,000
Pioneer Southwest noncontrolling interest transferred to APIC	0
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering		(49,072,000)
Deferred tax benefit associated with the Pioneer Southwest merger	200,091,000
Pioneer Southwest merger transaction costs	(3,880,000)
Net transfers from noncontrolling interest	364,896,000	(49,072,000)	35,019,000
Net income (loss) attributable to common stockholders and transfers from noncontrolling interest	(473,518,000)	143,213,000	869,508,000
Units Issued, Tax		23,700,000
Sale of Common Units	9.5	1.8
Sale of Units, Tax		15,400,000
Pioneer Southwest [Member]
Sale of Pioneer Southwest common units, net of tax			35,091,000
Issuance of Pioneer Southwest common units, net of tax			48,792,000
Issued Common Units		2.6
Additional Paid-In Capital [Member]
Pioneer Southwest noncontrolling interest transferred to APIC	(168,685,000)
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering		(49,072,000)
Deferred tax benefit associated with the Pioneer Southwest merger	200,091,000
Pioneer Southwest merger transaction costs	(3,880,000)
Additional Paid-In Capital [Member] | Pioneer Southwest [Member]
Sale of Pioneer Southwest common units, net of tax	0	0	26,915,000
Issuance of Pioneer Southwest common units, net of tax	0	0	8,104,000
Pioneer Southwest noncontrolling interest transferred to APIC	(168,685,000)	0	0
Deferred tax provision attributable to 2008 Pioneer Southwest initial public offering	0	(49,072,000)	0
Deferred tax benefit associated with the Pioneer Southwest merger	200,091,000	0	0
Pioneer Southwest merger transaction costs	$ (3,880,000)	$ 0	$ 0