Membership Interests (Schedule Of Distributions Paid) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Dividends Payable [Line Items]
Amount	$ 165	$ 110
Payment One FY 2015 [Member]
Dividends Payable [Line Items]
Declaration Date	Feb. 25, 2015
Payment Date	Feb. 26, 2015
Amount	$ 100
Payment Two FY 2015 [Member]
Dividends Payable [Line Items]
Declaration Date	Apr. 29, 2015
Payment Date	May 15, 2015
Amount	$ 65