Asset Retirement Obligations 3 Narrative (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2010 Panhandle [Member]	Dec. 31, 2011 Hurricane Ike [Member]	Dec. 31, 2009 Hurricane Ike [Member]	Dec. 31, 2008 Hurricane Ike [Member]
ARO [Line Items]
Asset Retirement Obligation, Liabilities Incurred	$ 1,162	$ 29,872	$ 10,770	$ 28,600		$ 8,300	$ 33,800
Asset Retirement Obligation, Revision of Estimate	(412)	(11,395)	(3,246)	11,400
Asset Retirement Obligation, Liabilities Settled	$ (16,836)	$ (19,858)	$ (1,557)	$ 19,700	$ 16,600

Amount of the Increase or Decrease in the amount of the asset retirement obligation during the current period for changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 143

-Paragraph 22

-Subparagraph c(4)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)(4)

-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Name:	us-gaap_AssetRetirementObligationRevisionOfEstimate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration