Derivative Assets And Liabilities Partnership's Derivative Assets And Liabilities, Amount Of Gain/(Loss) Reclassified From AOCI Into Income (Effective Portion) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Amount of Gain/(Loss) Recognized in Income Representing Hedge Ineffectiveness and Amount Excluded from the Assessment of Effectiveness	$ 6	$ 21	$ 2	$ 17
Amount of Gain/(Loss) Recognized in Income on Derivatives	(2)	(140)	5	(214)
Losses on interest rate derivatives	(25)	(81)	(20)	(151)
Commodity Derivatives - Trading [Member]
Amount of Gain/(Loss) Recognized in Income on Derivatives	15	(7)	26	(16)
Commodity derivatives
Amount of Gain/(Loss) Recognized in Income Representing Hedge Ineffectiveness and Amount Excluded from the Assessment of Effectiveness	6	21	2	17
Amount of Gain/(Loss) Recognized in Income on Derivatives	8	(48)	(2)	(43)
Other Income (Expenses) [Member] | Embedded Derivatives in Preferred Units [Member]
Amount of Gain/(Loss) Recognized in Income on Derivatives	$ 0	$ (4)	$ 1	$ (4)