Segment Information Schedule of Unconsoldiated Affiliate Assets Related to Balance Sheet (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Segment Reporting Information
Investment in unconsolidated affiliates	$ 2,224	$ 2,214
Gathering and Processing
Segment Reporting Information
Investment in unconsolidated affiliates	36	35
Corporate Joint Venture
Segment Reporting Information
Investment in unconsolidated affiliates	1,201	1,231
Contract Treating
Segment Reporting Information
Investment in unconsolidated affiliates	$ 987	$ 948

Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.12)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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