Valuation And Qualifying Accounts And Reserves (Schedule Of Valuation And Qualifying Accounts) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation and Qualifying Accounts [Abstract]
Balance at Beginning of Year	$ 81	$ 81	$ 87
Additions	24	37	35
Deductions	(32)	(32)	(39)
Other	(3)	(5)	(2)
Balance at End of Year	$ 70	$ 81	$ 81