Gains (Losses) on Sales and Impairment of Fixed Assets and Other Gains (Losses) on Sales or Impairments of Fixed Assets and Other Narrative (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Significant Acquisitions and Disposals [Line Items]
Asset Impairment Charges	$ 26
Rigs
Significant Acquisitions and Disposals [Line Items]
Number Of Drilling Rigs Leased	25
Lease Termination Costs	25
Oilfield Services
Significant Acquisitions and Disposals [Line Items]
Lease Termination Costs	25
Oilfield Services | Rigs
Significant Acquisitions and Disposals [Line Items]
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment	61
Midstream
Significant Acquisitions and Disposals [Line Items]
Asset Impairment Charges	6	43	21
Barnett Shale
Significant Acquisitions and Disposals [Line Items]
Asset Impairment Charges	26
Pipelines
Significant Acquisitions and Disposals [Line Items]
Impairment of Long-Lived Assets to be Disposed of	9
Land and Building | Other Operations
Significant Acquisitions and Disposals [Line Items]
Impairment of Long-Lived Assets to be Disposed of	$ 248	$ 3