Contingent Liabilities and Commitments (Details Textual) (USD $)								1 Months Ended
	Dec. 31, 2012	Dec. 31, 2012 Gas Pipeline	Dec. 31, 2012 Former Operations	Dec. 31, 2012 Natural gas underground storage facilities	Dec. 31, 2011 Gulf Liquids	Dec. 31, 2008 Gulf Liquids	Dec. 31, 2006 Gulf Liquids	Jan. 28, 2008 Gulf Liquids Gulsby-Bay	Jan. 28, 2008 Gulf Liquids Gulsby	Feb. 28, 2011 Pending or Threatened Litigation
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities	$ 46,000,000	$ 10,000,000	$ 29,000,000	$ 7,000,000
Estimated exposure for actual damages							68,000,000
Potential interest in addition to actual damages							20,000,000
Possible utlimate judgement in excess of accrual							199,000,000
Litigation award against Gulf Liquids, Damages								4,000,000	11,000,000
Loss contingency accrual reduction					33,000,000	43,000,000
Loss contingency accrued interest reduction					14,000,000	11,000,000
Assertion of Counterclaim										200,000,000
Loss Contingency, Range of Possible Loss	32,000,000
Commitments for construction and acquisition of property, plant and equipment	$ 1,300,000,000