Contingent Liabilities and Commitments (Details Textual) (USD $) In Millions, unless otherwise specified								1 Months Ended
	Jun. 30, 2013	Jun. 30, 2013 Gas Pipeline	Jun. 30, 2013 Former Operations	Jun. 30, 2013 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	$ 48	$ 11	$ 28	$ 9
Estimated exposure for actual damages							68
Potential interest in addition to actual damages							20
Possible utlimate judgement in excess of accrual							199
Litigation award against Gulf Liquids, Damages								4	11
Loss contingency accrual reduction					33	43
Loss contingency accrued interest reduction					14	11
Assertion of Counterclaim										200
Loss Contingency, Range of Possible Loss	$ 32