Contingent Liabilities and Commitments (Details Textual) (USD $) In Millions, unless otherwise specified			1 Months Ended				1 Months Ended
	Sep. 30, 2013	Dec. 31, 2006	Jan. 31, 2008 Gulsby-Bay	Jan. 31, 2008 Gulsby	Sep. 30, 2013 Northwest Pipeline LLC [Member]	Sep. 30, 2013 Former Operations	Feb. 28, 2011 Natural gas underground storage facilities	Sep. 30, 2013 Natural gas underground storage facilities	Dec. 31, 2011 Gulf Liquids	Dec. 31, 2008 Gulf Liquids	Dec. 31, 2006 Gulf Liquids
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities	$ 45				$ 11	$ 27		$ 7
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